Moelnlycke Health Care AB v Brightwake Ltd (t/a Advancis Medical)

In this action the claimant, Mölnlycke Health Care AB (“Mölnlycke”), claims that the defendant, Brightwake Limited (“Brightwake”), has infringed Mölnlycke’s patent number EP 0 633 757 entitled “A method and an arrangement for manufacturing wound dressings, and a wound dressing manufactured in accordance with the method.” The priority date is 30^th March 1992. The inventor is Tomas Fabo. The products alleged to infringe are Brightwake’s EPISIL and EPISIL ABSORBENT wound dressings. Brightwake denies infringement and contends that the patent is invalid. Brightwake contends that the relevant claims lack novelty and are obvious in the light of two prior documents, European Patent Application EP 0 251 810 A2 (“Brassington”) and United States patent 4,921,704 (“Fabo”).

Brightwake contends claims 6 to 10 are invalid and does not attack the validity of claims 1 to 5. The claims Mölnlycke contends are independently valid and infringed are claims 6, 7 and 10. The invalidity case pressed in closing was that Brassington anticipates claims 6 and 7 and renders all three claims obvious. The case over Fabo was obviousness only, certainly against claim 6 and as I understood it against claims 7 and 10 too.

Mr Iain Purvis QC and Miss Anna Edwards-Stuart appeared for Mölnlycke instructed by Mayer Brown International LLP. Dr Justin Turner QC and Mr Miles Copeland appeared for Brightwake instructed by Wragge & Co. LLP.

Mölnlycke’s first expert witness was Tomas Fabo. Mr Fabo is currently the Manager for Concept Development for the Wound Care Division of Mölnlycke. He obtained a Masters of Science degree in Chemical Technology from Chalmers University in Göteborg. In 1983 Mr Fabo joined Mölnlycke Hospital Products as a product developer/designer in the company’s wound care team. Since then he has worked full time for Mölnlycke. Mr Fabo is the inventor of the patent in suit and of one of the cited items of prior art.

Brightwake drew attention to his employment for Mölnlycke and his status as inventor of the patent and the prior art and to his involvement in United States interference proceedings in relation to the other item of prior art – Brassington. Mr Fabo did not know whether his involvement with lawyers in the interference proceedings had coloured his view of Brassington. Brightwake submitted Mr Fabo was poorly placed to assist the court as a result of this. They submitted he was too close to matters to express an opinion in some respects – such as obviousness over his own prior art patent. Mr Fabo’s personal relationship with the various documents and products in this case and his employment status are factors I must take into account in assessing his evidence. They do not disqualify him from being able to assist the court on the technical matters arising in this trial and in my judgment Mr Fabo did so.

Brightwake submitted Mr Fabo was notably evasive and uncomfortable when being cross-examined in relation to the arrangements for taking the electron micrographs in the case. In my judgment Mr Fabo was not at all evasive but he was uncomfortable. He had difficulty remembering what micrographs he had seen and when he saw them and he had difficulty remembering when he met Dr Eklund, the person who took the images. In my judgment his discomfort arose from his inability to remember precisely the details surrounding the electron micrographs when the events took place a matter of a few months ago. He was slightly embarrassed at not being able to remember these details, probably because they did not seem important to him at the time.

Some of Mr Fabo’s evidence on other issues in the case relates to development work he carried out nearly 20 years ago. Essentially no documents now remain from that work and Mr Fabo’s memory is the primary source of the evidence. I will deal with that in its proper context.

In summary Mr Fabo was a good witness. He gave his evidence entirely fairly.

Prof Clarson was called by Mölnlycke to address silicone. With a BA and D. Phil in chemistry from York, Prof Clarson is currently Professor of Chemical and Materials Engineering at the University of Cincinnati. He has five books on silicon/siloxane chemistry to his name as well as a number of patents. In 2000 Prof Clarson was elected a Fellow of the Royal Society of Chemistry. He has acted as an expert witness on silicon/siloxane chemistry in “dozens” of cases both in the USA and UK. He was a good witness.

Dr Dillingham is President and Chief Scientist of Brighton Technologies Group Inc., a materials research, development and testing laboratory in Cincinnati. He has a BS degree in biology, and an MSc and PhD in materials science. He gave brief evidence by video link relating to the experiments he carried out. He gave his evidence entirely fairly.

Prof Richard White was called by Brightwake. He is Professor of Tissue Viability at the Institute of Health and Society at the University of Worcester. He has over 35 years experience in dermatology and wound care and has published widely in those fields. He has a PhD in dermatological studies from Liverpool University. Following his PhD and post-doctoral work in the 1980s carried out in association with the Royal Liverpool Hospital, Prof White joined Squibb Pharmaceuticals as a section leader with responsibility for skin and wound healing. Then in the later 1980s he moved to ConvaTec and worked there in the development of wound dressings. Prof White left ConvaTec in 1999 and set up a consultancy. In 2004 he was a Senior Research Fellow in the Department of Tissue Viability at Aberdeen Royal Infirmary and in 2007 he took up his post at the University of Worcester. In the past 8 years Prof White has conducted consultancy work for Mölnlycke, Brightwake and Smith & Nephew.

Mölnlycke submitted that Prof White was clearly trying to help the court in his answers and was very knowledgeable about the clinical aspects of wound care however Mölnlycke submitted that care was needed with his direct evidence on infringement and validity. In relation to Brassington Mölnlycke submitted he had not read it with real care, particularly in relation to the way the word “coating” was used in the document. Prof. White distinguished between “coating” a substrate in which the silicone does not penetrate the surface and “encapsulation” when it does. He frankly admitted to an omission in that his definition could not apply to the examples and he agreed that the distinction needed revision. In my judgment the Professor was without doubt seeking to help the court and gave his evidence entirely fairly. However I have borne in mind that the elements of his written report which derive from the distinction he drew between “coating” and “encapsulation” required revision and cannot stand as they are.

Prof White’s report exhibited a fairly extensive collection of wound dressings and materials which was extremely useful. The cross-examination showed that part of his report relating to the materials used to make Brightwake’s product must have been prepared before he had been provided with a sample of one of Brightwake’s starting materials (MBPU with acrylic backing and release liner). However this did not undermine Prof White about the materials he was referring to in the report.

Prof White had not reconsidered his opinion on infringement in relation to the older Brightwake products after he had seen Mr Fabo’s evidence. He clearly understood that Brightwake’s other expert Dr Meirowitz was going to address that issue (which did not in fact happen). Mölnlycke criticised Prof White for that. In my judgment although it was unfortunate, it did not undermine the Professor’s evidence. It simply meant he had not addressed something.

Mölnlycke also submitted that Prof White’s views on the meaning of the word “carrier” were eccentric and took a point on his evidence about silicone gels and elastomers. I will address those in context.

Overall I have no doubt Prof White was a fair witness, helping the court. The specific points above are not trivial but in no sense did they vitiate his overall evidence. I will take the points into account in their context.

Brightwake also called Dr Meirowitz, a surface and advanced materials scientist. He has a PhD in chemistry from Boston University and is a Fellow of the Royal Society of Chemistry. After his PhD, Dr Meirowitz worked as a post-doc at the US Army Materials and Mechanics Research Centre and then in 1984 worked for Albany International Research Company (ALRESCO). Much of his work involved surface interactions, webs (including paper) and fabrics. He carried out experiments using silicone. In 1988 Dr Meirowitz went to Kimberly-Clark in Neenah, Wisconsin in its Research and Development Department. His work included basic and applied research on fluid flow through porous media, coating and other things. Silicone, its release behaviour and its skin interaction were topics he worked on. Dr Meirowitz also worked with melt-blown and spun bonded materials used in products like disposable personal care products and gowns. In 1994 Dr Meirowitz moved to Waters Corporation and in 1997 he moved to Nextec Applications, a company specialising in polymer encapsulation technology for a range of industries. From 1997 his work was almost exclusively focussed on silicones. In 2004 Dr Meirowitz formed his own company RnD Technical Solutions. This is a consultancy in the field of surface science. Dr Meirowitz has 18 US patents to his name.

Mölnlycke submitted Dr Meirowitz was “extremely inventive” as if that disqualifies him from giving evidence. It does not. Mölnlycke drew attention to Dr Meirowitz’s acceptance in cross-examination that his silicone expertise was not at the level of Prof Clarson. That point was not worth making. It was an answer demonstrating the witness’s combination of candour and modesty in his own achievements. Prof Clarson is in effect a professor of silicone chemistry, nevertheless Dr Meirowitz plainly had appropriate expertise in order to help the court in this case.

Mölnlycke also levelled a criticism of Dr Meirowitz which was the same coating/encapsulation point as was made concerning Prof White. However in my judgment whatever the position of Prof White, Dr Meirowitz’s evidence in his report (paragraph 48) was not open to this criticism. In summary Dr Meirowitz was a good witness.

Mr Cotton is the Development Director at Brightwake. His witness statement dealt with the Product Description and the changes in Brightwake’s process over time. He gave his evidence fairly in the witness box. Mölnlycke raised a point about the correspondence relating to Brightwake’s process which I will deal with in context.

Mr Jones, Brightwake’s patent attorney from Adamson Jones IP Ltd provided a witness statement dealing with what happened at the repeats of the experiments. He was not cross-examined.

A wound is a break in the skin. Dressings are applied to a wound in order to promote healing and prevent further injury. The dressings may have holes or perforations in order to allow for wound exudate to seep away from the wound. Wound dressings are sometimes called primary dressings to distinguish them from secondary dressings which are not in direct contact with the wound surface. Secondary dressings may absorb exudates from the wound or act as a barrier to infection or perform other functions.

Gauze, generally produced from woven yarn of cotton, viscose or a mixture has been widely used as a wound dressing. However as the skin surface cells grow across the healing wound (re-epithelialisation) the tissue growth encapsulates the gauze. Removing the gauze then causes severe pain and damages the wound. To address this problem a wound dressing known as tulle gras was developed in the First World War. This consists of simple gauze fabric impregnated with soft paraffin. The paraffin creates a greasy hydrophobic wound contact surface to reduce dressing adherence. Tulle gras type dressings are in use today. Smith & Nephew have a product called JELONET which Prof White exhibited. The dressing consists of a fabric net soaked in a greasy material. The fabric net is an approximately 2mm square grid of strands. The JELONET dressing itself is supplied in between two sheets of what feels like fairly thick grease proof paper. The grease proof paper is removed in use.

By the 1970s wound dressings consisting of clear polyurethane plastic films were available. These had an adhesive on the skin contacting side. These also remain in use today and the example exhibited by Prof White was a Smith & Nephew product called OPSITE FLEXIGRID. The OPSITE dressing consists of a thin plastic sheet, sticky on one side due to the adhesive and non-sticky on the other. The sticky side is the wound contact side. The OPSITE dressing is supplied mounted between a sheet of waxy release paper and a plastic sheet. Both the waxy paper and plastic sheet are removed in use.

Another kind of wound dressing from the 1970s and still in use today consists of a perforated plastic film and an absorbent pad. Prof White’s examples of this are MELOLIN and RELEASE. These are multilayered dressings. In MELOLIN there is a perforated plastic film which contacts the wound surface and an absorbent pad is fixed to the reverse side of the plastic film. RELEASE is a product of Johnson & Johnson in which the perforated plastic film surrounds the absorbent pad altogether. RELEASE is a sort of flattened tube of perforated plastic film with a pad inside. The pad is loose save for the seam made by the opposite edges of the plastic film holding it in place.

Other kinds of wound dressings in use before 1992 include the following:

This case is concerned with the use of silicone materials in wound dressings and since there was at least at one stage a dispute about what was and was not common general knowledge on that score I will address the point below.

The patent starts with the following:-

The present invention relates to a method and to an arrangement of apparatus for manufacturing wound dressings of the kind which comprise a perforated carrier material and a layer of hydrophobic silicone gel which lies against the wound, or sore when the dressing is worn. The invention also relates to a wound dressing manufactured in accordance with the inventive method.

Next, at Col 1 line 11 the patent states that “a wound dressing of this kind” is known from EP-A-0 261 167. That is in effect a reference to the Fabo prior art document relied on by Brightwake. The paragraph summarises the Fabo prior art product and how it is made. The carrier material is fully enclosed by the silicone gel. Its manufacturing involves guiding the material in a relatively complicated path.

Then at col 1 line 24-27 Brassington is mentioned. The patent states that Brassington discloses the features of the pre-amble of claims 1, 4 and 6.

At col 1 line 28 the patent states the object of the present invention as being to provide a method which will enable such wound dressings to be manufactured at a high production rate and in a simple and reliable manner. The patent does not here assert that the prior art dressings cannot be made at all, merely that there is a need for high production rates and simple and reliable manufacture. The patent continues (Col 1 ln 32) by stating that: “The invention also relates to apparatus for carrying out the method to a wound dressing suitable for manufacture by means of the inventive method.” I suspect, although nothing turns on it, that the word “and” is missing from between “the method” and “to a wound dressing”.

The document then continues with three paragraphs which are in effect consistory clauses:

Exemplifying embodiments of the invention are then described by reference to Figures 1, 2 and 3. This section runs from col 2 line 7 until col 4 line 55. There is then a general section relating to the invention which runs until the claims. In a number of places the document refers to a “wound or sore”. Nothing turns on any distinction between a dressing for a wound or a sore.

Figure 1 illustrates part of an arrangement for manufacturing an inventive wound dressing and figure 2 illustrates the air flow through the perforations in the carrier material when the method is in use. Most of the details of the arrangement are not important for the present case but some points did arise.

The method involves coating a perforated carrier material (col 2 line 29-31) with a thermosetting silicone mixture which includes components which, when cured, form a chemically cross-linked sticky silicone gel. Example of such a gel is given and one (from Dow Corning) is said to be the gel specified in the earlier Fabo patent application EP-A-0 261 167. This cross-reference was argued to have a bearing on a point of claim construction (the tacky point) which I will address below.

The particular arrangement in figure 1 uses two air blowing units (4 and 5), one after the other. The carrier material carrying the uncured silicone mixture – which is a thick viscous fluid – first passes over unit 4. This blows cold air on the underside so that the air passes through the holes and prevents clogging. Blower unit 5 then blows hot air onto the underside with a view to begin the curing of the regions around the perforations (col 3 line 3-5). After the second air blower unit, the carrier material is passed into a curing oven to cure the silicone.

In the paragraph starting at col 3 line 16 the patent explains why the carrier material needs to be more or less impervious to air and fluid as follows:-

In order to prevent the silicone mixture from being blown from the carrier material, it is essential that the carrier material is impervious to air, or at least so impervious that essentially all air will flow through the perforations. However, material which permits air to diffuse therethrough can be used beneficially when practicing the invention. The carrier material shall also be impervious to fluid, or at least have a fluid-permeability which is so low that the thick-viscous fluid, i.e. the silicone mixture prior to curing, is unable to run therethrough.

Thus the carrier material needs to be sufficiently impervious to air such that when the air is being blown on the underside, the air flow will be through the perforations rather than through the carrier material itself. However the carrier material can be “breathable” – i.e. allow air to diffuse through to the wound when in use. The material also has to be sufficiently impermeable to fluid that the uncured or partially cured silicone mixture does not just run through.

The paragraph at col 3 line 26-29 gives examples of a number of suitable carrier materials. They are relatively soft plastic sheets and examples include polyurethane film and silicone film.

Next the specification turns to how to ensure good adhesion between the silicone gel and the carrier material. To achieve this the plastic sheet may be microporous so as to present a large surface area (col 3 line 29-33) and/or a silicone primer may be used (col 3 line 34-36). The specification continues:

Another method of ensuring good adherence between silicone gel and carrier material is to use a perforated two-ply material as the carrier material. This two-ply material may, for instance, consist of a laminate which comprises a plastic sheet and a layer of non-woven or textile material which can be laminated with the aid of heat or a binding agent. The two-layer material may also be comprised of a coated fibre material having a plastic film moulded on one side thereof. (Col 3 line 37-45)

This passage was focussed upon by both sides and I will return to it below. At this stage it is sufficient to note that the idea mentioned in the passage is that the uncured silicone will be applied to the non-woven or textile side of the two-ply laminate so that the silicone sticks better.

At col 3 line 46 the specification turns to consider the side of the carrier material which is not coated with silicone gel. This is another paragraph subjected to close analysis by the parties. It reads:-

That side of the carrier material which is not coated with silicone gel will preferably have a uniform and smooth surface, so as to have low adherence to any dried wound fluid which may have exuded through the perforations as the dressing is worn. This is particularly important when the dressing is used together with an overlying absorbent body or pad, since it must be possible to remove the absorbent body without the dressing being disturbed as a result of wound fluid that has dried on the absorbent body adhering to the carrier material and entraining the material in the initial stages of removing the absorbent body.

One of the points being made here is that because the outside of the carrier material is not coated with silicone gel, it needs to have a uniform and smooth surface in order to give it a low adherence to exudate coming through the perforations so that an absorbent pad placed on top can be readily removed.

Figure 3 (and col 3 line 58 to col 4 line 17) is then referred to which illustrates a variant of the perforated carrier material with cup shaped projections around the holes. These are said to reduce the risk of uncured silicone running into the perforations (amongst other things). The specification states that using this carrier material therefore obviates or greatly reduces the need for blowing hot air onto the carrier before it passes to the oven. A point was taken at one stage that this passage was an express example of making a wound dressing without using the air blowing method at all – and cup shaped projections were mandatory. However this passage is not concerned with an example which avoids air blowing altogether. It is only the second, hot air blower, which may be dispensed with (see fig 1 item 5).

The paragraph at col 4 line 18 compares the method of the invention to the one used in the Fabo prior art. The method of the invention allows the carrier material to be transported at higher speed than before and allows the conveyor path to be guided much more easily.

A variant of the method is mentioned at col 4 line 32-39 in which the carrier material stays put and the nozzles and air blowers move and various other modifications to the machinery are set out from lines 40-55.

In the next part of the specification the patent moves on from the embodiments in the figures and deals with other general matters. At col 4 line 56 the specification takes stock as follows:-

This invention thus provides a simple and effective method of manufacturing a wound dressing having a layer of hydrophobic silicone gel which is intended to lie against the wound or sore, and a layer of carrier material which when the dressing is worn faces outwardly and which is not sticky and will not adhere to clothing and the like. As in the case of the aforesaid known dressing, the layer of hydrophobic silicone gel which lies against the wound or sore is soft and adheres to dry skin, and the inventive dressing will therewith facilitate healing of the wound in the same beneficial fashion as the known dressing. According to the present invention, the silicone gel is comprised of chemically cross-linked, two-component addition-curing silicone gel.

Thus the carrier material when worn faces outwardly and is not sticky and not adherent to clothing. Obviously this is because the sticky hydrophobic silicone gel is only on the wound contacting side.

Next in the paragraph at col 5 line 11 the specification mentions that the carrier material will preferably have 0.5-200 perforations per cm² which will be preferably 0.1 – 2mm in diameter. These ranges are not incorporated into any of the claims. Advantages of the inventive method are mentioned, in particular that the method allows for smaller sized perforations to be used without them clogging during manufacture.

The properties of the silicone gels to be used are discussed in the passage from col 5 line 21 until the claims at col 6 line 50. The gels are soft and will adhere to dry skin but not to the wound (col 5 line 22-23). This “extremely low or weak adhesion to wounds” as compared to other “so called non-adhesive” dressings is apparently due to the gel having low surface tension and surface chemistry which gives rise to types of adhesion forces on the wound surface which are different from those arising using other polymeric materials. The gel also retains its original form when handled normally and does not undergo plastic deformation when the dressing lies against the wound, when the dressing is removed or when protective strips are peeled off (col 5 line 34-37). The strength at which the silicone gels adhere to dry skin is much lower than the adhesives on self adhesive tapes used to secure wound dressings and so the skin will not be damaged or injured by the adhesive silicone gel when the inventive dressing is removed.

The other matters mentioned in this part of the specification are: a method for determining the adhesive strength of the silicone gel onto dry skin; methods for measuring the hardness, penetrability and tensile strength of the silicone gel and finally a method for estimating the adhesive strength of the gel on dry skin by sticking the gel on a steel plate.

The patent has 10 claims. The independent claims are claims 1, 4 and 6, being claims to a method for making a wound dressing (1), an arrangement for making a dressing (4) and a wound dressing (6). Claims 1 and 4 are not alleged to be infringed and not attacked by Brightwake. As well as claim 6, Mölnlycke rely on claims 7 and 10 as claims which are said to be infringed and independently valid.

Claims 1 and 4 are as follows:

1.

A method of manufacturing wound dressings including the step of applying a coating of curable silicone mixture (3) to the upper surface of a perforated carrier material (2) and then applying heat to the silicone mixture until it has cured, characterized by blowing cold air onto the underside of the coated carrier material so that the silicone mixture is blown away from the perforations in the carrier material so as to form through penetrating perforations and prevent clogging of the perforations in the carrier material before the applying of heat.

4.

An arrangement for manufacturing a wound dressing which comprises a perforated carrier material (2) and a layer of hydrophobic silicone gel (3), which arrangement includes means (1) for coating the upper surface of the carrier material with a mixture of components which when cured by means (5) for delivering heat to the component mixture applied to the upper surface of the carrier material form a silicone gel, characterized in that the arrangement includes an air-blowing unit (4) which functions to blow cold air onto the underside of the carrier material so that the silicone mixture is blown away from the perforations in the carrier material so as to form through penetrating perforations and prevent clogging of the perforations in the carrier material and which is placed opposite the coating means

Claim 6 is the main claim in this case. Divided into suitable integers it provides for:

The relevant dependent claims are claims 7 and 10, as follows:-

7 A wound dressing according to claim 6, characterized in that the carrier material (2) is comprised of a relatively soft plastic film.

10 A wound dressing according to any one of claims 7 - 9, characterized in that the carrier material is comprised of a two-ply material, including a plastic layer and a layer of fibre material.

The only other claim with any significance at all was claim 9 which calls for a silicone primer. It is mentioned here only to dispose of the point. At one stage it was submitted that claim 10 incorporated all the features of claim 7 because of the interlocking claim dependencies but that is not right because claim 10 via claim 9 can be read through to claim 6 without claim 7. However since Brightwake do not use a silicone primer, the point was of no significance and can be ignored.

A patent specification is addressed to those likely to have a practical interest in the subject matter of the invention, and such persons are those with practical knowledge and experience of the kind of work in which the invention is intended to be used. The addressee comes to a reading of the specification with the common general knowledge of persons skilled in the relevant art, and he reads it knowing that its purpose is to describe and demarcate an invention. He is unimaginative and has no inventive capacity.

The patent is directed to a person or team interested in developing wound dressings. Such people will have previous experience of developing such dressings. Making changes or adapting dressings or making new dressings will be part of that team’s day to day business. That does not mean that the skilled team is inventive in nature, which would be wrong in principle. However it does reflect the reality of the kind of tasks they would be called upon to perform in this field. A degree of adaptation and change is routine in this art.

The major dispute between the parties was whether a person familiar with coating silicone (a “silicone specialist”) was part of the skilled team. Brightwake submitted that the team would include an individual accustomed to working with silicone and familiar with coating techniques. Mölnlycke submitted to the contrary. It submitted that wound dressing manufacturers did not employ silicone specialists at that time, based on the fact that Mölnlycke itself did not employ such a specialist in 1992. It had Mr Fabo. By 1992 Mr Fabo had been working with silicone on wound dressings for at least two years following his work which led to the Fabo prior art patent. Although he was not quite a silicone specialist, by 1992 Mr Fabo was someone sufficiently familiar with silicones and their use in wound dressings for Mölnlycke to develop dressings using them. However Mölnlycke submitted that the ordinary range of products produced by manufacturers in 1992 was pretty basic and required no more than general engineering and manufacturing skills.

In my judgment a silicone specialist would be a member of the team for all relevant purposes. Although I can quite see that a team concerned with wound dressings in general would not include a silicone specialist, the team for this case would immediately seek and acquire such a specialist at the point at which they wanted to seriously contemplate employing silicone. I say this for three reasons.

First, such people plainly existed. There were in 1992 people with expertise in silicones and in coating silicones generally. Both sides called witnesses (Prof Clarson and Dr Meirowitz) with experience of that kind. The silicone specialist may no doubt not have coated a wound dressing before but they would be familiar with handling silicones and the various possible techniques available for coating substrates using them.

Second the patent requires the use of silicone. From the point of view of putting the patent into practice, a team which started without a silicone specialist would obviously be entitled to ask for help from such a person. A team trying to make the wound dressing of claim 6 who failed without asking a silicone specialist would not in my judgment have tried hard enough. It would be unfair to the inventor to regard that failure as a serious effort to put the invention into practice.

Third the cited prior art also requires the use of silicone. If silicone had been a feature of the claimed invention which was not mentioned in the cited prior art then it could be very unfair to put a silicone specialist in the skilled team but that is not this case. When the prior art document relied on expressly calls for silicone coating, in my judgment a team or person in this art considering such a teaching would plainly consult someone with relevant knowledge and experience about it.

The position of Mölnlycke themselves in 1992 does not counteract these factors. Mr Fabo, although not an expert in silicones at that time was not a novice either. He had already developed one silicone coated product (called Mepitel) which is the subject of the Fabo prior art. That fact that Mölnlycke chose not to go beyond Mr Fabo’s knowledge and experience is more likely to be a testament to Mr Fabo’s personal qualities than it is evidence of what the notional skilled team would comprise. Johnson & Johnson were at that time selling a silicone coated dressing (Silicone NA) and there was no evidence one way or the other whether they employed silicone specialists.

The law as to what constitutes common general knowledge is set out in the decisions of the Court of Appeal in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457 at 482-483 and Beloit Technologies Inc v Valmet Paper Machinery Inc [1997] RPC 489 at 494-495.

The common general knowledge will include all the matters set out above in the Technical Background section, which are not controversial.

Two textbooks were referred to in the evidence. In 1990 an edition of Wound Management and Dressings by Thomas had been published. It was described as the “bible” for wound dressings. It was common ground that it represented the common general knowledge in that respect. The other book was a Formulary of Wound Management Products by Morgan. In the end nothing turned on its status.

Two particular points on common general knowledge which bear consideration are silicones in general and their use in wound dressings in 1992.

Silicon is a group 4 element in the periodic table like carbon. Its chemical symbol is Si and its atomic number is 14. It is very common. It occurs commonly in combination with oxygen in silica (SiO₂) in the form of sand or quartz. Silicon is well known as the basis for integrated circuits in the computer industry.

Silicon forms compounds analogous in some ways to the compounds of carbon. Silanes are a class of compounds containing silicon and other elements such as hydrogen, carbon and chlorine. Prof Clarson explained that the simplest silane, also confusingly called just silane (SiH₄), is the silicon analogue of methane (CH₄).

Silicones are synthetic polymers. They are a diverse family of liquid, semisolid and solid polymers with a linear repeating silicon-oxygen backbone and organic side groups attached to the silicon atoms by carbon-silicon bonds. The most common form of silicone is polydimethylsiloxane (PDMS), a repeating silicon-oxygen backbone with methyl side groups attached to the silicon atoms. The nature of the side groups and the structure of the backbone chain can be altered to create silicone based materials with a range of properties from oils to stiff rubbers. The chain lengths can vary over a wide range and molecular mass. The chains can be linear or circular.

In some cases the organic groups can be used to link two or more silicone polymers. This is called cross-linking or curing. It is often conducted in the presence of a suitable catalyst. In some cases (addition curing) a platinum catalyst is used. Addition cure precursor kits (commonly called A/B kits) come as two containers of liquid silicone precursors, one of which contains the platinum catalyst. The precursors are mixed and applied to a substrate. The precursors then cure to a solid or semi-solid silicone product, depending on parameters such as composition, cure temperature and cure time. A different kind of curing reaction (condensation curing) is used for example to make bathroom sealants. When those products cure the condensation reaction produces acetic acid, which explains why a newly sealed bath smells of vinegar.

The nature and extent of this cross-linking reaction and the wide range of starting materials means that what Prof Clarson described as an almost infinite number of silicone products can be synthesised. Silicone products have a vast range of physical and chemical properties. They include oily fluids, gels, elastomers and resins. They find uses as greases, adhesives, sealants, coatings, lubricants and emulsions and they are used in all kinds of fields including the biomedical and pharmaceutical industries, food processing, cosmetics, personal care, automotive and packaging fields.

One class of two component silicone systems are the Room Temperature Vulcanisates or RTVs. The two components start with a relatively low viscosity but begin to cross-link when mixed and undergo curing. Ultimately, depending on the cross-linking, the product can have gel-like, elastomeric or resin like properties.

Rubber is the paradigm example of an elastomer. Elastomers are solids which can be deformed elastically but will spring back into shape. A gel is a semi-solid material. As compared to an elastomer, the silicones in a gel have not been fully cross-linked. In general silicone elastomers tend not to be tacky to touch whereas gels are tacky. This is not surprising because just as the difference between gels and elastomers is down (in part) to cross-linking, so also tackiness is determined by the degree of cross-linking amongst other things. The distinction between gels and elastomers and between tacky and non-tacky products is an issue to which I will return.

In 1992 many types of silicone were commercially available from companies like Dow Corning and Wacker. They produced silicones and would customise silicone formulations to suit a customer’s requirements. At that time (and today) silicones were a very commonly used coating material because they have a low surface tension, low adherence but can be formulated to be tacky, are relatively easy to work with, fairly soft and have a good temperature range for flexibility. Silicone coatings were commonly applied to a wide range of substrates.

There were many well known techniques for applying silicone to a substrate. These included various forms of knife coating in which a silicone is applied to the substrate and a blade or knife scrapes the silicone over the substrate. The height angle and type of blade dictate the characteristics of the coating. Using a “doctor blade” is a form of knife coating. A “bird film applicator” functions by a form of knife coating. Spraying on the silicone is another form of coating forming part of the common general knowledge. There were many other techniques generally available too but these are sufficient for the purpose of this case.

The need to employ an element of trial and error was part of the skilled person’s common general knowledge in respect of the application of silicones. This is not the same thing as saying the skilled person was inventive, which they are not by definition. In the relevant field, there were many parameters to vary both in terms of the silicones themselves and the coating techniques. The skilled person was very familiar with the empirical nature of the field and knew to vary the parameters in order to aim for success in a given task.

In 1992 silicone gel sheets were used in the related field of the prevention of burn scars and to minimise tissue overgrowth associated with hypertrophic scarring. A product called Silastic Foam was used in which the two components were mixed in situ on the wound and formed a foam. Both the gel sheets and the foam were part of the common general knowledge of a wound dressing manufacturer. Neither is an example of a wound dressing involving a substrate coated with silicone.

More relevant were products known as Mepitel and Silicone N-A. Mepitel was Mölnlycke’s own product (invented by Mr Fabo) which comprised a mesh completely encapsulated with a tacky silicone gel. Although it ultimately became a successful product neither side contended that Mepitel had become common general knowledge by 1992.

At the opening of the trial Mölnlycke were agnostic as to whether Johnson & Johnson’s Silicone N-A product had reached the status of common general knowledge by 1992. However by the closing submissions Mölnlycke accepted that Silicone NA was common general knowledge by the priority date. Silicone N-A (also known today as N-A Ultra) was what Prof White described as a non-tacky siliconised mesh dressing. It had been available since 1990 and was used for ulcers and granulating wounds. Silicone N-A feels smooth to the touch. The silicone is not soft and not tacky.

Silicone was used in breast implants and there had been bad press and litigation arising from that use. However the skilled person knew that silicone had a role to play in wound dressings.

In Kirin Amgen Inc v Hoechst Marion Roussel [2004] UKHL 46, [2005] RPC 9 the House of Lords comprehensively reviewed the principles applicable to patent construction under the 1977 Act bearing in mind Article 69 of the European Patent Convention and the Protocol on the Interpretation of Article 69. Construction of a patent claim is purposive in nature and the question is always to work out what the person skilled in the art would have understood the patentee to be using the language of the claim to mean (see Lord Hoffmann at paragraph 34).

In Virgin v Premium Aircraft [2009] EWCA Civ 1062, [2010] RPC 8 the Court of Appeal (Jacob and Patten LJJ and Kitchin J) set out the correct general approach at paragraphs 5 and 6 of the judgment of the court. There is no need to lengthen this judgment any further by setting it out.

The Court of Appeal’s judgment went on to address three specific points of principle concerning the extent to which the skilled person is supposed to take knowledge of the patent system into account. Two of those points (numerals and divisionals) are not germane to the present case. The other issue is the approach of a skilled reader to a claim cast in “pre-characterising” and “characterising” parts. Two extracts from the judgment are pertinent. First in general the Court considered Kirin Amgen:

12.

First in Kirin-Amgen itself Lord Hoffmann said that the skilled reader:

[33] … reads the specification on the assumption that its purpose is to both describe and demarcate an invention – a practical idea which the patentee has had for a new product or process.

And:

[34] … it must be recognised that the patentee is trying to describe something which, at any rate in his opinion, is new ..

13.

So the skilled reader is taken to suppose that the patentee knew some patent law – that his claim is for the purpose of defining the monopoly and that it should be for something new. Knowledge of that may well affect how the claim is read – for instance one would not expect the patentee to have used language which covered what he expressly acknowledged was old.

Then on the particular point about pre-characterising and characterising parts of claims the court held:

20.

From this [certain EPO cases] Mr Vanhegan invited us to conclude that the skilled reader would have no, or at the very least only a slight presumption, that the pre-characterising portion of a claim was describing what the patentee considered to be old. He particularly emphasised the Board's statement that it is "primarily relevant to the patent grant procedure." Mr Meade on the other hand submitted that when the skilled man sees a pre-characterising clause he will strongly incline to the view that the skilled man saw that as being old. And that inclination will be reinforced (perhaps steepened is a better word) where the clause concerned is clearly said by the patentee to be based on prior art which he specifically acknowledges.

21.

We accept Mr Meade's contention. Even without a two-part claim structure, because the skilled reader knows that the patentee is trying to claim something which he, the patentee, considers to be new, he will be strongly averse to ascribe to the claim a meaning which covers that which the patentee acknowledges is old. And if the patentee not only acknowledges that a particular piece of prior art is old but then has a pre-characterising clause which is fairly obviously based on it, the skilled reader will be even more strongly inclined to read that clause as intended to describe that old art.

These aspects of Virgin v Premium Aircraft have a bearing on the present case not just because claim 6 is drafted in a characterising form but also because the patent at col 1 line 23-27 states that the Brassington prior art discloses the preamble of claim 6 (and claims 1 and 4 for that matter). In fact both items of prior art cited in this case (Fabo and Brassington) are referred to in the specification. Brightwake press a case that claim 6 covers what is disclosed in Brassington and therefore lacks novelty. Mölnlycke contend that the claims are novel. Although in argument Mr Purvis did not seek to pray in aid the point made in Virgin v Premium Aircraft (that one would not expect the patentee to have used language which covered what he expressly acknowledged was old), nevertheless it seems to me that I should not ignore this principle when dealing with the issues.

A final general point on construction to bear in mind is the observation of Pumfrey J in Halliburton v Smith International cited above in Virgin v Premium Aircraft that over-meticulousness in verbal analysis is not to be equated with carefulness. Care in working out what the patentee was aiming at when he chose the words he used is absolutely necessary.

During the cross-examination of the experts Mr Purvis objected to various lines of questioning by Dr Turner which, Mr Purvis submitted, infringed the rule about the admissibility of the evidence of experts on the meaning of words. I did not disallow any of the questions at the time and the cross-examination proceeded. The parties resumed their dispute about the admissibility of such evidence in their closing submissions.

Dr Turner relied on a passage from the judgment of Aldous LJ in Hoechst Celanese v BP Chemicals [1999] FSR 319. The passage bridges p326-327 as follows:

Mr Watson, Q.C., who appeared for the plaintiffs, submitted that the judge was right to hold that prima facie the word “dimension” should, appearing as it does in a patent specification, be given its scientific meaning. He submitted that there was a rebuttable presumption that when a word was contained in a technical document, such as a patent specification, it was used as a technical word.

Despite being referred to authority which suggests that technical words in technical documents should prima facie be given the technical meaning, I do not believe that there is a rebuttable presumption that words in a patent specification that can have a technical meaning do have that technical meaning. The court is entitled to hear evidence as to the meaning of technical words and thereafter must decide the meaning from the context in which they are used. A patent specification is a technical document to be construed by the court with the advantage of the knowledge of the notional skilled man in the art. Where, as in this case, the dispute between the parties turns upon whether the word “dimension” is used to denote diameter or volume, it would be wrong to start the task of construction with any preconceived idea. Having obtained the knowledge of the notional skilled man, the specification must be read as a whole to ascertain its meaning and from that the court has to decide the ambit of the monopoly claimed using the guidance in the Protocol.

In response Mr Purvis relied on Scanvaegt v Pelcombe [1998] FSR 786 at p795 -796 where Aldous LJ cited a famous passage from the House of Lords in British Celanese v Courtaulds:

The respondents also submitted that the construction now advanced by the appellants was contrary to the evidence. So what? The words under consideration did not have their technical meaning in statistics and none of the witnesses were experts on construction of patent specifications and therefore could not give any worthwhile evidence as to their meaning. In those circumstances construction of the claim is for the court. The words of Lord Tomlin in British Celanese Limited v. Courtaulds Limited (1935) 52 R.P.C. 171 at 195 are still apt:

The proceedings in the Trial Court provide an illustration of the licence which in these days in cases of this kind is enjoyed by expert witnesses and by Counsel examining them.

In my judgment the time has come to curtail that licence whatever be the difficulties involved in doing so.

The area of the territory in which in cases of this kind an expert witness may legitimately move is not doubtful. He is entitled to give evidence as to the state of the art at any given time. He is entitled to explain the meaning of any technical terms used in the art. He is entitled to say whether in his opinion that which is described in the specification on a given hypothesis as to its meaning is capable of being carried into effect by a skilled worker. He is entitled to say what at a given time to him as skilled in the art a given piece of apparatus or a given sentence on any given hypothesis as to its meaning would have taught or suggested to him. He is entitled to say whether in his opinion a particular operation in connection with the art could be carried out and generally to give any explanation required as to facts of a scientific kind.

He is not entitled to say nor is Counsel entitled to ask him what the specification means, nor does the question become any more admissible if it takes the form of asking him what it means to him as an engineer or as a chemist. Nor is he entitled to say whether any given step or alteration is obvious, that being a question for the Court.

What Lord Tomlin said in 1935 is particularly applicable today when a witness's evidence is contained in a Witness Statement. Inadmissible evidence should not be included. It would normally be appropriate to take that into account when deciding who should pay costs.

Of course what Lord Tomlin said about obviousness has not been the law or practice in England at least since Mölnlycke v Procter & Gamble [1994] RPC 49.

The law is clear enough albeit not always easy to apply in the midst of cross-examination for all kinds of reasons. For one thing it is often necessary to make sure everyone knows what the witness understands a word to mean in order to understand their answer and one example of this point arose in relation to the word “disingenuous” in the cross-examination of Mr Cotton. The law is that experts can properly explain the meaning of any technical terms. That evidence is admissible. But they are not experts in the construction of patent specifications and evidence along those lines is not admissible. A word may have a technical meaning but the court may conclude that the word is not being used in that sense in the patent. So far so good, but the debate about admissibility can end up chasing its own tail because one side contends the word has a special technical meaning which differs from its meaning in a dictionary because their expert has given it such a different meaning. The other side says the evidence is not admissible because the word does not have a technical meaning, and round the argument goes. I will deal with any technical terminology in the claims as they arise.

Dr Turner also relied on the reference in Scanvaegt v Pelcombe (above) to a lie detector calibrated in Pinnochio units. This goes to the proposition that although lack of clarity is not a ground of invalidity of a claim, an ambiguous claim may be so unclear that the patentee cannot establish infringement (Aldous LJ p797). The real point as I understand it is this principle shows that it is not mandatory to arrive at a concluded unambiguous construction of every term in a patent claim. It may in a proper case turn out that the process of claim construction ends with a claim which is just ambiguous in certain respects.

The terms in claim 6 which fall to be considered are:-

On the basis of an answer from Prof White given in cross-examination Brightwake submitted that carrier material may be a term of art, i.e. a term with a technical meaning. This was on the basis that Prof White said it would not be a term of art in his own field as a wound care clinician but he suggested it would be a term of art in the field of wound care development. He explained that colleagues of his in that field would be talking about carrier materials in dressings they were developing and so he himself was familiar with the term. In my judgment that evidence does not make “carrier material” a technical term on which evidence is admissible as to its meaning. No technical dictionary was produced in evidence which included this expression. I have no difficulty whatever in accepting Prof White’s evidence that he became familiar with the expression having heard it being used by technical people in the field of wound care development but that does not make the term a technical term with a special meaning in this art which differs from its meaning as a matter of ordinary English.

Mölnlycke had submitted that Prof White’s meaning for the term was eccentric. I do not need to resolve that. Eccentric or not Prof White’s evidence on the meaning of that term was not relevant.

The true construction of the term carrier material in the patent is an issue which seems straightforward at first sight. The patent acknowledges that a wound dressing comprising a perforated carrier material and silicone gel were known. The patent expressly refers to the Fabo prior art in this context (see col 1 line 11 referring back to col 1 line 3-8) and cites Brassington as disclosing the pre-amble for the independent claims. The term perforated carrier material is in the pre-amble of all three claims 1, 4 and 6. In the patent the uncured silicone is poured onto the perforated carrier material, the air is blown through the perforations in the carrier material and the cured silicone ends up coated on only one side of the carrier material because the uncured material does not flow through the holes in the carrier material nor does it seep through the impermeable carrier material. As a result when the dressing is worn the carrier material which faces outwardly is not sticky and will not adhere to clothing.

However construction of the term is more complicated than it might appear because the patent discloses and claims processes (i.e. methods) as well as products. Claim 1 is to the air blowing method (and claim 4 to a machine for doing it). However claim 6 (and its dependent claims) is not limited to the method of claim 1. Claim 6 claims a wound dressing however made. Looking ahead, this aspect of claim 6 is vital for Mölnlycke because it is common ground that Brightwake does not use the method of the patent. The perforations are made after the silicone is cured by punching out holes. No air flow is involved. I will return to that subject below.

This distinction between processes and products means that care needs to be taken when construing the terms in the claims in the context of the specification as a whole (see paragraph 27 of the judgment of Lord Neuberger MR in Fabio Perini v LPC and PCMC [2010] EWCA 525). When claim 1 refers to a perforated carrier material it is referring to the material onto which the curable silicone mixture is coated during the manufacturing process. It is the underside of that material onto which the air is blown and it is through the perforations in it that the air flows. The same goes for the parts of the specification which describe the process. However claim 6 relates to a wound dressing which need not have had any perforations in it when the uncured silicone was applied.

The matter is not helped by the title of the patent. This refers only to a “wound dressing manufactured in accordance with the method”. There is no doubt that despite the title, claim 6 is not so limited. Also the consistory clause at col 2 line 1-6, although obviously corresponding to claim 6 in general terms actually differs from the claim in a similar way. The pre-amble at col 2 line 2-3 before the words “characterised in that” states that the wound dressing is one which is “suited for manufacture by means of the aforesaid method”. By contrast the pre-amble to claim 6 says nothing about suitability for being manufactured by the method.

Important parts of the patent are clearly only concerned with a wound dressing made by the method described. The title is one such. So also is the general statement of the object of the invention (at col 1 line 28-31) to provide a method which enables “such wound dressings” (i.e. the prior art dressings of Fabo and Brassington) to be made at high production rate and in a simple and reliable manner. The skilled reader would understand the passage at col 1 line 28 onwards to be a teaching that the invention is a method. It is a better way of making perforated wound dressings just as were found in the prior art. The invention also related to wound dressings themselves but those were wound dressings “manufactured in accordance with the inventive method” (see the very first paragraph at col 1 line 8-9).

The skilled person, reading the document as a whole, would see clearly that whatever the inconsistencies, as it stands the claim to a wound dressing is not limited to wound dressings made by the method nor to wound dressings suitable for being made by the method. Thus although “carrier material” in claim 6 would (one might think) be given the same meaning as “carrier material” in claim 1, the reader would appreciate that care is required. The term “carrier material” appears both in the context of the method and in the context of the final product, but it is important not to lose sight of the context within the document of the particular passage being considered.

For example although the perforated carrier material has the uncured silicone poured onto it in the method, claim 6 does not require that the carrier material had to have perforations in it when the uncured silicone was applied. Thus the words “coated with” in the phrase in claim 6 feature (v) “the carrier material is coated with silicone gel” are not referring to the method at all. The words describe the wound dressing as it stands and not how it came to get there. In claim 1 the stage in the process described is prior to the application of heat. What is applied is a “coating of curable silicone”. So the carrier material in claim 1 carries the uncured silicone mixture. However in claim 6 the silicone is cured. It is a silicone gel.

In my judgment claim 6 would cover a product made in the following way. A gauze coated with silicone gel on both sides (such as Mepitel) is fixed to uncoated impermeable polyurethane film. Perforations are punched in the structure. The wound dressing has all the features of claim 6 and plainly so. The point of this example is to distinguish between the process and the product. In my judgment deciding what is a carrier material within claim 6 is not a question of what layers may or may not have had silicone applied to them during manufacturing because claim 6 is not a process claim (nor is it a product by process claim).

The carrier material in claim 6 is just the material in the actual wound dressing which carries the silicone gel. It is the part with the silicone on one side. How uncured silicone was applied and to what is not relevant.

The patent takes for granted that the skilled reader knows why one might wish to have perforations in the carrier material and does not rehearse the reasons for perforations. It was part of the skilled person’s common general knowledge that perforations were used in wound dressings in order to allow for wound exudate to seep away from the wound. At col 3 line 29 the patent explains that the plastic sheets which are suitable carrier materials may be microporous. That is a different concept. The pores are not “perforations”, they are present to assist adhesion between the silicone and the plastic sheet.

Again although method claim 1 requires the carrier material to already be perforated before the uncured silicone is applied to it, there is no such requirement in claim 6. The carrier material has to be perforated but it does not matter when that took place.

Claim 6 mentioned silicone gel twice. The claim requires a layer of hydrophobic silicone gel which lies against the wound surface when the dressing is worn and the claim also requires that the carrier material is coated with silicone gel on only one side. Thus one needs to know what “silicone gel” is both in order to ensure there is the correct layer lying against the wound surface but also to ensure that one does not have the wrong substance on the outer surface of the carrier material. As it turns out in this case the latter point is of more significance than the former.

It is clear that as a matter of common general knowledge the skilled person can and will distinguish between a silicone gel and a silicone elastomer or rubber. It is also clear that whether the material is tacky or not is an important factor in that respect. I was struck by Mr Fabo’s reaction in cross-examination when the Silicone N-A (aka Ultra N-A) product was put to him. It consists of a mesh coated all over with silicone. It is not tacky. Mr Fabo said instantly “But that is not a gel”.

Brightwake submitted that the silicone gel referred to in the patent (and in claim 6 in particular) was a tacky material and submitted that the skilled person would construe the claim in that way. They relied on Dr Meirowitz’s evidence that in his view the term “silicone gel” was being used in the patent primarily to refer to cured tacky softer silicones.

Mr Purvis submitted that “gel” was not a term of art and evidence of this kind fell foul of the observations of Lord Tomlin referred to in Scanvaegt (above). In my judgment the term “silicone gel” is a technical expression and evidence is admissible from the experts in order to resolve that meaning. However it does not follow that the skilled reader would understand the patentee in this patent to have used the term in a strict technical sense. That is another matter.

On the evidence, although tackiness is probably the most significant characteristic which those skilled in the art take into account if asked whether a given silicone material is a gel or an elastomer, it is not the only characteristic. I accept the evidence of Dr Meirowitz that a silicone gel is a state between the uncured fluid starting material and a fully cross-linked elastomer. Mr Fabo explained that the Silicone N-A product was not a gel because “it is not a gel-like feeling and it is not soft and it is not tacky also”. He also said “it really feels like an elastomeric silicone”. Brightwake also relied on Mr Fabo’s acceptance that his own Mepitel product (which is tacky) is a gel. Moreover Brightwake put to Mr Fabo and he accepted that a gel is essentially a polymer network suspended in a liquid.

Prof White had given evidence about gels and elastomers but admitted in cross-examination that it was not his area. I will not take his evidence on that into account.

In my judgment the technical meaning of “silicone gel” is a silicone material comprising a polymer network suspended in a liquid. It is a state intermediate between uncured fluid and a fully cross-linked elastomer. Although the boundaries are fuzzy, the skilled person regards gels, elastomers and resins as generally different things. Those skilled in the art understand that although silicone gels are usually tacky and elastomers are usually not tacky, the line between tackiness and non-tackiness is not necessarily co-extensive with the distinction between gels and elastomers. A skilled person might well regard it as unusual to encounter an elastomer which was tacky but that encounter would not falsify the skilled person’s understanding of the difference between a gel and an elastomer. Equally in some cases the usage of the terms overlaps so that some products could be described both as a gel and as an elastomer. However, no skilled person would be surprised to see someone in the art assuming that gels are tacky and elastomers are not.

I will now turn to consider the patent. There is no doubt the patent is drafted on the basis that the silicone gel is likely to be sticky. This can be seen from col 2 line 31 (“a chemically cross-linked sticky silicone gel”). The passage at col 5 line 21-23 is important. Here the patent states that “the silicone gels used in accordance with the present invention are soft and will adhere to dry skin but not to the wound or sore.” So, submits Brightwake, the patent says in terms that the silicone gels used in the invention adhere to dry skin (which means they are tacky) and so that property must be read into the claims by means of interpreting the term “silicone gel”. The only gels mentioned in the patent are tacky gels and the claim must be referring to those tacky gels when it calls for “silicone gel”.

This argument is very similar to the argument which carried the day in Kirin-Amgen. In that case the claim referred to a “host cell”. The only host cells in the patent in question were ones with a particular characteristic – they were hosts to exogenous erythropoietin DNA. Thus “host cell” was held to mean a host to exogenous erythropoietin DNA and did not include host cells which were hosts to other DNA but not exogenous erythropoietin DNA. By contrast in Fabio Perini v LPC and PCMC [2010] EWCA 525 the Court of Appeal rejected a submission that the term “slit” in claim 16 of the patent in question should be interpreted as being “an opening formed by a pair of inclined plates forming the tip of a nozzle through which glue flows”, even though such an opening was indeed the only slit described in the specification. At paragraph 25 -26 of his judgement Lord Neuberger MR said :-

25.

Looking at the immediate documentary context, reading claim 16 on its own does not provide any support for the conclusion that one should give the term "a slit" the rather artificially narrow meaning which PCMC suggests. Indeed, unless there is any other persuasive reason to the contrary, it would seem almost perverse to attribute to the patentee an intention to use the word "slit" in a rather artificially narrow sense. It involves attributing to the patentee a desire to limit unnecessarily the scope of the claim, and, therefore, the extent of his monopoly. (It is fair to say that if PCMC's insufficiency argument, discussed in the passage at paragraphs 51-55 below, had been correct, that might provide a sound reason for its case on the meaning of "slit", but, for reasons given in that passage, the insufficiency argument is bad.)

26.

PCMC also argues that if one refers to certain passages in the specification of the 929 Patent, they justify the narrow interpretation of "a slit" for which it contends. The two primary passages on which PCMC relies are quoted in the judgment below at [2009] EWHC 1929 (Pat), paragraphs 51-52, and constitute descriptions of specific apparatus. But the fact that a particular type of slit in specific apparatus is called "a slit" in a document which includes a description of that apparatus, cannot justify the notion that, whenever the document uses the term "a slit", it must have the same limited and specific meaning. As Perini says in its skeleton argument, just because "the word 'slit' is used when describing the gap between the plates of a nozzle … it does not follow that 'slit' is therefore used to mean that."

In some cases it can be seen that the invention would be understood on a particular basis (e.g. host cell being a host to exogenous erythropoietin DNA) and the claims must be understood on that basis too. Other cases it is clear that the language of the claims was not used in such a way as to import a limitation. Each case must be decided on its own facts.

The factors in favour of Mölnlycke’s submission that tackiness should not be read into claim 6 could be summarised as the following. First, the skilled reader would know that (as I have found) gels are usually tacky, elastomers are usually not tacky but the gel/elastomer boundary is not, as a matter of technical necessity, the same as the tacky/nontacky boundary. Second the passage at col 2 line 31 which mentions a “tacky silicone gel” shows that the draftsman was quite capable of calling the gel tacky if they wanted to. Third tackiness itself is a vague quality and the skilled person knows that. The skilled person would see that the draftsman has chosen not to make the claim boundary potentially uncertain by incorporating an uncertain term. Fourth the specification includes a test for the degree of adherence to dry skin at col 5 line 46 – col 6 line 5. The test ends with a statement that the adherency measured this way “shall lie within the range 5-200g … in order to provide satisfactory adhesion and dressing peelability”. However this dry skin test is not in the claims and the skilled reader would see that the draftsman chose deliberately not to put it there. Brightwake did not submit that this test should be imported into the claim but it seems to me that the logic of Brightwake’s reliance on the passage at col 5 line 21 which states that the silicone gels used in the invention will adhere to dry skin would lead in that direction. The description of the adherence test follows directly from the passage Brightwake relies on. Fifth, the specification includes a further adherence test – on steel plate (see col 6 line 35 et seq). That test is not incorporated either. It ends with the words “a silicone gel suitable for use with an inventive dressing will have an adhesive force within the range of 0.5-10 N/mm” measured by the test. The presence of this test reinforces the fourth point. If a requirement for adherence or tackiness is to be read into the claim, which test does one choose?

The factors in favour of Brightwake are the following. Undoubtedly the patent refers to the silicone gel as sticky (col 2 ln 31), states in terms that the silicone gel “will” adhere to dry skin and states in terms that a silicone gel suitable for use with an inventive dressing “will” have an adhesive force (as measured by the steel plate method) within a certain range. Moreover for the dry skin adherence test the adherence measured “shall” lie in a certain range in order to be satisfactory. A different point is that the Fabo prior art referred to in the patent as being concerned with “silicone gel” is in fact about tacky silicone gels, so perhaps “tacky” is to be taken as read. Finally the point of coating only one side of the carrier material with silicone gel is to keep the sticky side against the wound and make sure the outer face is not sticky.

Weighing up these factors, I am reminded that the words of the claim are paramount. I do not accept that this patent should be construed in such a way that a concept which is not mentioned in the claim (tackiness) should be read in as if it were. In my judgment the skilled reader would understand that the patentee had used the term “silicone gel” to refer to the material itself. The skilled reader would understand that the patentee had not intended to import into the claim any particular level of tackiness or adherence to dry skin.

Feature (iv) of claim 6 provides that:

These words really relate to two features – one about air and the other about fluid. The purposes are explained in the specification at col 3 line 16 onwards.

The point of being impervious or only slightly permeable to air is to allow the air blowing method to work during manufacture. Imperviousness is concerned with air flowing through the material and is different from mere air diffusion. During manufacturing the air must blow through the holes and not through the material itself otherwise the uncured silicone may be blown off.

The skilled person would see that the patentee used the words “or only slightly impermeable” to make it clear that total imperviousness to air was not necessary. The material has to be impervious enough to work. “Working” in this context means being sufficiently impermeable to air so that the air will flow through the holes. Of course this concept is only actually relevant if the product is made by the process of claim 1. It is of no relevance if the holes do not even exist until after the silicone has cured in place. However just because the limitation may seem to be unnecessary does not mean it can be ignored.

The point of being impervious or only slightly permeable to fluid is to make sure the uncured silicone mixture is unable “to run therethrough”. Again this relates to the process of manufacture. As with air permeability, the skilled person would see that the patentee used the words “or only slightly impermeable” to make it clear that total imperviousness to fluid was not necessary. The material has to be impervious enough to work. “Working” in this context means being sufficiently impermeable to the silicone mixture prior to curing so that it is unable to run therethrough.

However the fact that the skilled reader would understand that both aspects of feature (iv) only make sense in the context of the manufacturing process would not deflect the reader from their clear understanding that the draftsman did not write claim 6 as a claim to a product defined by how it was made (a form of product-by-process claim). It is entirely clear that claim 6 claims a wound dressing as a product itself. The draftsman can be seen to have chosen to claim broadly by separating the defined product from its method of manufacture. The reader can see that the draftsman has done that quite consciously in order to encompass wound dressings made in ways the patent does not describe or contemplate.

Brightwake submitted that these features (air and fluid) each rendered the claim so ambiguous as to be uninfringeable following Scanvaegt. The problem with the air feature was said to be that unless the skilled person built a machine in accordance with claim 1, they could not tell whether the material satisfied that feature. However no skilled person would understand the patentee to have used those words to mean that a machine along the lines of the apparatus described in the patent had to be built to test this property. There is no evidence before me of any real difficulty in assessing whether a given carrier material has the relevant property. Dr Turner in the course of his submissions demonstrated that a sheet of MBPU alone could be held up in front of his face and blown through. It would fail the test. Equally it is perfectly obvious that other materials in this case satisfy the test and Brightwake did not contend otherwise. No doubt in theory at least there is a grey area in which it might be difficult to tell and if such a case arose then the Scanvaegt principle might apply and infringement by that product may not be provable. But such a case is not before me.

The problem with the fluid feature is more serious. The first question Brightwake pose is to identify the fluid concerned. Since different fluids will have different properties and may interact with a given material in different ways one does need to know what sort of fluid the claim is referring to. The purpose of the feature relates to the behaviour of uncured silicone mixture and while their properties vary as well, since the wound dressing of claim 6 comprises a silicone gel, so the fluid must presumably be the particular uncured silicone mixture which when cured makes up the gel.

However the limits of permeability by an uncured silicone mixture depend on the curing time. For RTVs the curing time can vary from seconds to days. It will also depend on temperature. No criteria for this are set in the patent. Mr Fabo’s evidence was that for a high speed commercial machine curing would take place in a short time. A curing period of 5 minutes would make the process very expensive to run and Mr Fabo could not imagine a process that slow. In his view normal commercial machines would involve curing in less than a minute or even less than 15 seconds depending on temperature. However as Brightwake point out the patent is not limited to a process running at high speed.

The permeability will also depend on the pressure applied and this pressure may derive simply from the amount of uncured silicone loaded onto the material. This point became apparent from the submissions of Mölnlycke to deal with a point arising from its experiments aiming to prove that Brightwake’s material satisfied this part of the claim.

Mölnlycke’s experiment poured uncured silicone onto a sheet of the material said to be the relevant carrier material (MBPU and acrylic adhesive). Mölnlycke says none came through and so the claim is satisfied. Brightwake says in fact some silicone could be seen to get through on the repeats. Mölnlycke maintains its primary case that not enough silicone to matter came through the material. However Mölnlycke also contends as follows:-

The issue is the true interpretation of claim 6. Mölnlycke’s case is that the claim can be judged based on criteria derived from the manufacturing process by which the product has actually been made. The submission has a seductive appeal but in my judgment it should be rejected. By drafting a product claim the patentee is making it clear that the process by which the wound dressing is made is irrelevant. The monopoly conferred by a product claim is absolute. Although in this case we happen to know how Brightwake actually make the product because their facility is in the UK and they are the manufacturer, that is happenstance. The seller of a product will infringe if the product is within the claim. Why should they care how it was made? The seller may have no means of finding out even if they wanted to. This divorcing of the process from the product is the key reason why product claims are put in patents. Process claims already confer on the patentee the ability to restrain products obtained directly by means of that process (s60(1)(c) 1977 Act and Art 64 EPC). The point of a product claim is to confer a broader monopoly.

As it happens Brightwake use a technique in which the uncured silicone precursor kit is poured onto a substrate as part of their process. That allows for the points above to be made. If they did not do that then Mölnlycke’s points would not get off the ground but claim 6 would still have to be satisfied. Prof Clarson explained that there are other specialist techniques for applying silicones involving plasma vapour deposition and chemical vapour deposition and do not involve the precursor kits. There is nothing in claim 6 which demands that only products made in a certain way are covered.

In any event if consideration of these difficulties in interpretation of claim 6 drives one to a conclusion that the process by which the wound dressing is made must be relevant then the only tenable outcome of that approach would be that the process to be used is the one described in the patent which involves coating a perforated carrier material and blowing air through the perforations to keep them unclogged. That is the true context in which the features of air and fluid permeability are disclosed in the patent. That would not be the right construction of claim 6 but an even less legitimate construction would be an intermediate one with some process elements but not others.

My conclusion on the fluid aspect of feature (iv) is the same as my conclusion on the air aspect. The evidence before me shows that a skilled person would have little difficulty in assessing the permeability to uncured silicone of many materials. The test in Mölnlycke’s Notice of Experiments on this is not complex. Plainly MBPU itself is not at all “impervious or slightly permeable” to fluid. Brightwake’s experiment shows the fluid pouring through. Equally plainly many materials are thoroughly impervious to fluid. Neither side suggested that the PU film used on the outer face of Episil was anything other than impervious. So assessing impermeability is not intrinsically unworkable. There is obviously a grey area in between which may or may not be one in which the skilled person can be satisfied about the qualities of a given material. That would be a matter of evidence. If the material cannot be shown to be impermeable to silicone to the relevant extent then it is not within the claim.

The skilled reader would see that the patent expressly makes the point that the known wound dressing of the Fabo prior art (EP-A-0 261 167) has silicone gel uniformly distributed on both sides of the carrier material (col 1 line 20). Coating silicone gel on one side is one of the characterising features of claim 6. It is important.

The reason for coating with silicone gel on only one side is explained in the passage from col 4 line 56 to col 5 line 10. The reason given here for coating gel on one side only is concerned with adherence or lack of it. The layer of silicone gel which lies against the wound is soft and adheres to dry skin (col 5 line 4-5) whereas, because that adherent gel is not on the outer side of the carrier material, that side is not sticky and will not adhere to clothing and the like (col 5 line 1-3).

Although in my judgment “tackiness” cannot be read into claim 6, the skilled reader would understand that the description works on the basis that the silicone gel it is talking about is soft and adheres to dry skin, i.e. is tacky. Thus the explanation for coating on only one side make sense. Silicone gel is not wanted on the outer surface because silicone gel is likely to be tacky and stick to things like clothing.

Thus claim 6 includes what could be called a negative feature. There is a place (the other side of the carrier material) which must not be coated with silicone gel.

As part of their case on infringement, Mölnlycke submits that if they can find a subset of the layers of a laminate coated with silicone gel which subset satisfies the requirements of carrying the silicone gel, being sufficiently impermeable to air and fluid, being perforated and being coated on only one side, then those layers are a relevant carrier material within claim 6 and the wound dressing would infringe regardless of the state of the other parts of the laminate. To some extent Brightwake made a similar submission in that they contend that a different subset of layers in the laminate (the MBPU layer alone), which does not satisfy the requirement for imperviousness, is the carrier material and takes their product out of infringement.

In my judgment both of these approaches are wrong as a matter of construction of claim 6 for the same reason. The carrier material referred to in claim 6 is the material in the wound dressing which carries the silicone gel. The “one side only” requirement makes no sense if the “carrier material” can be a sub-set of layers within a multilayer laminate. The patent is not concerned with avoiding silicone gel in the interior of the structure. An interior notional “side” of a subset of the layers would not risk adhering to clothing if it was coated with tacky silicone gel. In the case of a multilayer laminate, that laminate is the material which carries the silicone gel on the wound contacting side and therefore it is the outer face of the carrier material laminate which needs to be free of silicone gel too.

Imagine a perforated polyethylene sheet impermeable to air and silicone fluid which has been painted with silicone gel on only one side. It could be a wound dressing and all other things being equal would fall within claim 6. Now imagine another plastic sheet in all respects identical to the first one. It may or may not be made of a different plastic, e.g. polyurethane. It too would fall within claim 6 (all other things being equal). Now what happens if the skilled person glued the two sheets together by their uncoated faces? There would now be a laminate material. Mölnlycke’s construction of claim 6 would mean that this structure would satisfy the claim even though it had silicone gel on both sides. The argument would say that the carrier material for one layer of silicone was the polyethylene sheet. What that sheet is stuck to would be argued to be irrelevant. The polythene sheet is coated on only one side regardless of what it is stuck to. The skilled person would not approach the claim in that way.

Before leaving claim 6 there is a point I must address pulling together the consequences of the various elements of construction. The Brassington prior art is cited in the patent as the preamble to claim 6. One might assume therefore that the patent as a matter of construction has to be construed in such a way as to be novel over Brassington (see above and see also Beloit v Valmet [1995] RPC 705 at 720 and Ultraframe v Eurocell [2005] RPC 36 at para 47). After all a skilled reader conversant with patent practice would know that the characterising features of claim 6 are meant to distinguish the claim from the prior art.

However it is not the law that a patent cannot be anticipated by prior art acknowledged in the specification. The characterising part of claim 6 has two features – the impermeability point and coating on only one side. Are they both to be understood as a matter of construction as distinctions over Brassington? The impermeability point certainly excludes the gauze type embodiments of Brassington. That gets rid of all the examples of Brassington.

The three examples in Brassington also refer to the silicone coated on both side of the material as gel. It may be that claim 6 can be explained on the basis that the draftsman of the patent regarded Brassington as a disclosure limited to silicone gel on both sides. However there is an argument about Brassington’s use of language and apart from the examples, elsewhere Brassington clearly refers to coating one side with “tacky silicone gel” and the other side with “non-tacky silicone elastomer”. How does that affect the construction of claim 6? Might it mean that silicone gel in claim 6 actually has to include all the silicones in Brassington whether they are gels or elastomers, tacky or non-tacky because otherwise claim 6 might cover Brassington?

In their opening skeleton (paragraph 87) Mölnlycke characterised Brassington as being concerned with a substrate “fully coated (on both sides) with silicone” and as a teaching in which “the substrate is fully sealed by the silicone”. Note here no reference to “gel”. So to some extent Mölnlycke do seem to have contended that anything with silicone on both sides is outside claim 6. However this is wrong because the patent contemplates that silicone can be on both surfaces of the carrier material. Silicone film is an expressly contemplated carrier material – col 3 line 28. When coated on only one side with silicone gel, there will be silicone gel on one side and silicone film on the other. So claim 6 cannot be read as excluding something with silicone on both sides.

There is no indication in the patent in suit that the draftsman even noticed the reference to plastic films in Brassington or regarded it as important. After all Mölnlycke submit it was a throw away line. Points like this proliferate endlessly once one embarks on trying to construe the patent in suit by reference to its own terse back reference to Brassington. How much patent law and practice does one credit the skilled reader with? Does one take into account that draftsmen of all documents sometimes realise that they may have no alternative but to leave a point unclear in order to give one scope to argue in the future?

A close analysis of Brassington cannot have a bearing on the construction of claim 6 even though Brassington is cited in the patent. The canon of construction which involves reading a claim to avoid cited prior art cannot be taken that far. It only works when it is clear what specifically the patentee was referring to in the prior document and when it is clear what distinction the patentee was drawing. Those things are not clear in this case.

A point on construction arose in relation to claim 7 about the ambit of the word “plastic”. Brightwake submitted that the word “plastic” in “plastic film” meant the same as the word “plastic” in “plastic deformation”. In my judgment “plastic film” means a film made of plastic, i.e. the material it is made of; whereas plastic deformation refers to the particular property of a substance (such as mild steel) which can be deformed and keeps its shape once the force has been removed. Plastic deformation is distinguished from elastic deformation, which springs back once the force has been removed (see e.g. rubber). I doubt “plastic film” is a term of art at all although the concept of “plastic deformation” is a technical one. In case terms of art are involved I should record that Mr Fabo did not accept Brightwake’s point when it was put to him.

In my judgment claim 7 is referring to films made of plastics. The patent gives examples at col 3 line 26: polyethylene, polyamide, polyurethane and silicone. The characteristic being referred to is the material from which the film is made. It is not concerned with plastic deformation.

A point did arise on claim 10 which may have a bearing on the issue whether a subsets of layers can be a carrier material.

Claim 10 calls for the carrier material to be comprised of a two-ply material, including a plastic layer and a layer of fibre material. The relevant passage in the specification is the paragraph at col 3 line 37. This explains that in order to ensure good adherence between the silicone gel and the carrier material, a two ply carrier may be used e.g. a layer of plastic sheet and a layer of textile laminated together. The uncured silicone is obviously supposed to be applied to the textile side (although claim 10 does not say so) because that way adherence will be improved as the silicone keys into the textile. Brightwake points out that the lamination can be achieved using a binding agent. Brightwake draws a comparison between this arrangement and its (new) product. Its product has a fibrous layer, a binding agent and a plastic sheet. However Brightwake points out that despite this three layer structure, Mölnlycke argues that Brightwake’s carrier material is just the fibrous layer and binding agent and not the plastic sheet. Brightwake replies that when the three layer structure is described in the patent, the carrier material from the point of view of claim 10 is the fibre layer plus the plastic layer, and so it submits that this should be true for the Brightwake product as well.

The binding agent mentioned in the specification is not explained in any detail. However it can be said that the patent is indifferent to the properties of the binding agent. Whether it actually ends up covering the whole surface of the plastic sheet is irrelevant. It does not matter whether the binding agent happens to stop uncured silicone gel seeping as far as the plastic sheet during manufacture or whether the “carrier material” can only include the plastic sheet if some uncured silicone reaches as far as the plastic sheet, past the binding agent and stops there. These considerations have nothing to do with identifying the carrier material in the patent. To this extent the passage provides some support for the idea that the carrier material is not identified by focussing on a subset of layers in a laminate.

There are four Brightwake products alleged to infringe, the old and new forms of Episil and Episil Absorbent. They are all made in a similar way which I will explain first and then deal with the differences.

Brightwake’s manufacturing method starts with a sheet which is a laminate of MBPU (melt blown polyurethane), acrylic adhesive and a release liner. It buys this product in from third parties. The laminate is coated with uncured silicone. At this stage it is unperforated and so there is no question that Brightwake make no use of the patented method of claim 1, nor the apparatus of claim 4. There is no need for either. Once the uncured silicone has been laid down a further sheet of polyethylene is placed on top of the silicone and the product is wound onto a roll and allowed to rest. After Brightwake’s silicone is cured, holes are punched in the material. It is the sandwich of polyethylene, silicone, MBPU, acrylic adhesive and release liner into which 5mm diameter holes are cut.

After cutting the holes the sheets on both faces of the sandwich are changed. The polyethylene sheet in contact with the silicone is removed and replaced with a two part polyethylene release liner. This two part polyethylene release liner remains in place until use. When the dressing is to be applied to a patient the two part release liner is removed to expose the silicone gel.

During manufacture, once the holes have been cut, the release liner in contact with the acrylic adhesive is removed and replaced with a polyurethane (PU) backing film. This PU backing film remains in place in use. It is part of the wound dressing. It is permeable to air and allows the wound to breathe at least to some extent but it has no holes. Mölnlycke does not contend it is perforated.

The description above relates to the Episil product. The other relevant product is called Episil Absorbent. The difference between the two is that Episil Absorbent has an absorbent pad in between the acrylic adhesive layer and the PU film. For a given wound dressing the pad is smaller in area than the whole wound dressing so that around the edge of the dressing, beyond the pad, the PU film is stuck on the acrylic adhesive just as in Episil. The pad is not removable from the dressing, it is an integral part of it. Just as in Episil the PU film is unperforated.

The process by which Brightwake makes its products has changed over time. In the past heat was applied by an infrared pre-heater unit which was capable of raising the local temperature of the MBPU to well over 120°C. This heating process produced what I refer to as the old products (it applies to both Episil and Episil Absorbent). The new products are the ones which are without the heating step. Broadly the difference between the old and new products can be seen by simple visual inspection of the dressings. The new ones have a more cloudy appearance whereas the old ones are somewhat less cloudy (although not wholly transparent).

Mölnlycke contend that the heating step in the old process melted the MBPU fibres and led to their forming a continuous layer. On the evidence it is clear that melting took place and it is clear that the MBPU fibres in old products do not appear to be a fibrous mat to the same extent the new ones do. The old product has more of a continuous layer as compared to the new. Mr Cotton for Brightwake accepted as much. So there is undoubtedly a distinction between the new and the old products. I will still use the term MBPU to refer to the layer which started as MBPU even though the fibres have melted.

The Brightwake products alleged to infringe are all made from multi-layer laminates which, in use, do not have holes running all the way from the wound side to the outside. The PU film has no perforations, the holes are only in the silicone/MBPU/acrylic region.

To fall within claim 6 a wound dressing must comprise a perforated carrier material which material satisfies the claimed requirements of imperviousness to air and fluid and which is coated on only one side (the wound side) with silicone gel. Three candidates for the carrier material in Episil were identified in argument. They are (a) the MBPU, acrylic and the PU film together (and including the absorbent pad in Episil Absorbent), (b) the MBPU layer alone, and (c) the MBPU layer and the acrylic adhesive layer. Brightwake contend the carrier material is (a) or (b), Mölnlycke contend it is (c).

If the carrier material is (a) then given that the 5mm diameter holes in the silicone gel /acrylic layer do not extend to the PU film, the carrier material on this basis is not perforated. If the carrier material is (b) then Brightwake argue it is not impermeable as required by claim 6 and so does not infringe. At least for the new Episil product Mölnlycke agree, there is though an issue about the old Episil product. For candidate (c), Mölnlycke submit that the silicone gel and acrylic together are impermeable to air and silicone in the relevant sense and are perforated and so, they contend there is a carrier material in the Brightwake product which satisfies the features of claim 6.

In my judgment approaches (b) and (c) are both wrong. As a matter of construction the carrier material of the wound dressing of claim 6 is not identified by looking at a subset of the layers in a laminate. The relevant carrier material from the point of view of claim 6 is identified by finding the material in the wound dressing which carries the silicone gel. The material in all the Episil/Episil Absorbent wound dressings which carries the silicone gel is the whole laminate (approach (a)). That carrier material is not perforated and neither Episil nor Episil Absorbent (new or old) infringes.

Another way of looking at the matter is the following. If Brightwake painted silicone gel on the outer face of their PU film in Episil, on Mölnlycke’s case Episil would still infringe because the “carrier material” is only the MBPU plus the acrylic adhesive – which would still have no silicone gel on one side of it. This would be bizarre and wrong.

Mölnlycke also submit that counting the top layer of PU film as part of the carrier is nonsensical because the silicone is not applied to the PU film in the manufacturing process. It is applied to the MBPU/acrylic laminate and then cured in place. The PU film comes later. They argue that the MBPU/acrylic does not then cease to be a carrier layer. It is doing precisely the same job as it did before. In my judgment Mölnlycke’s argument mixes up the disclosure of the process in the patent with the fact that claim 6 clearly claims a wound dressing however it is made. Claim 6 is not concerned with how the wound dressing came to be made, it is concerned with a product in its state as a wound dressing.

In fact the argument oversimplifies the Brightwake process. The material to which the uncured silicone is applied is not just MBPU and acrylic, it is the bought in laminate of MBPU, acrylic and release liner. So the carrier material during this stage of the process is really the whole laminate. But that whole laminate does not exist in the final product. That does not mean there is no carrier material at all from the point of view of claim 6, it simply serves to emphasise that claim 6 is not concerned with the process by which a given wound dressing has been made; it is concerned with the product.

Finally Mölnlycke rely on the passage in the patent which mentions an absorbent pad at col 3 line 45-57. They say that this passage shows that the patent contemplates placing additional layers on top of the carrier layer which are not perforated. It contends that this is exactly what is found in the Brightwake products. It argues that Episil Absorbent follows precisely the teaching of this passage in the patent with an absorbent pad on top of the plastic layer (by which Mölnlycke means the acrylic adhesive) which has perforations in it. The PU backing is only placed as a final layer.

It can also be said that when the absorbent pad referred to at col 3 line 45-57 is in place, the surface which claim 6 requires to be free of silicone gel is then a sort of interior surface in the overall structure, just like Episil Absorbent.

It would indeed be surprising if the claims did not cover what is described at col 3 line 50-52. I accept Mölnlycke’s submission that the claim would be expected to cover this embodiment. The construction I have reached in this judgment does that however. The fallacy in the argument is to equate the passage in the patent with the Brightwake product. Crucially the absorbent pad referred to in the patent must be removable. It is placed on the outer surface of the carrier material and then taken off again. The passage in the patent is not concerned with wound dressings which have built in absorbent pads which one cannot remove without removing the whole dressing. The patent is concerned with a situation in which “it must be possible to remove the absorbent body” without the wound dressing being disturbed.

Mölnlycke’s submission based on col 3 line 50 is that the patent contemplates placing additional layers “on top of the carrier layer” (sic) which are not perforated and are not treated as part of the carrier material. For one thing the claim does not refer to a carrier “layer”. More importantly the submission is only true to the extent that the only additional “layer” mentioned in the patent is a removable absorbent pad. That is not part of the carrier material in that example not least because it is not part of the dressing of the invention at all. It is an extra thing which can be used with it. Apart from anything else the passage Mölnlycke relies on is clearly written on the basis that the pad is not the same thing as the dressing (see line 51 “the dressing is used together with an overlying absorbent body or pad” and line 53 “it must be possible to remove the absorbent body without the dressing being disturbed”). No other additional layer is mentioned in the specification.

It is striking that the perforations which undoubtedly exist in the Episil products reach from the wound to the absorbent pad in the Episil Absorbent product and in that sense correspond to the perforations referred to at col 3 line 49 and perform the same function. However this is only part of the issue. Episil Absorbent is an integral product which is not described in the specification. Therefore there is no reason as a matter of construction of the specification why claim 6 “must” cover it. The carrier material in Episil Absorbent is still the whole composite because in the wound dressing as used and sold, the material which carries the silicone gel is the whole thing. If one asks where is the place in an Episil Absorbent type product which should not be coated with silicone gel to be within claim 6 the answer is the same as the answer for Episil. It is the surface of the PU film. That is the place which would get stuck to clothing if it had sticky silicone gel on it. That is the surface on which a coating of silicone gel is to be avoided. That is the top of the carrier material.

It is true that claim 6, by using the word “comprising”, allows for the possibility that the claimed wound dressing may have more to it than a perforated carrier material and a layer of hydrophobic silicone gel but that does not advance Mölnlycke’s point. If “comprising” was replaced by “consists of” then the claim would be very restrictive indeed. It would be simple to avoid infringement by adding a further structure - say adhesive tabs on the edges of the carrier material. The use of the word “comprising” prevents that. A wound dressing otherwise within claim 6 with adhesive tabs on the edges would still infringe.

However “comprising” in claim 6 does not allow for the claim to be interpreted as if particular further elements such as an integral absorbent pad or even an extra unperforated layer have been disclosed in the specification and demand inclusion within the claim.

On that basis the products do not infringe any of claims 6, 7 or 10.

In deference to the arguments before me and in case the matter goes further, I will deal with the facts which need to be found if my approach to construction is wrong and either approach (b) or (c) to the carrier material point was the right one.

If the MBPU alone is the relevant carrier material then there is no doubt the unheated MBPU of the new product is outside claim 6. The thin fibrous material lets uncured silicone pour through it. Mölnlycke did not dispute that. Dr Turner held up a sheet in court to show that it is also easy to blow through and so does not satisfy claim 6 as far as air is concerned. There is no dispute about that either. Thus on approach (b) neither new Episil nor new Episil Absorbent infringes.

However the old Episil (and Episil Absorbent) is a different matter. Mölnlycke submit the melting of the fibres by the old heating process produces a film of melted polyurethane fibres which is sufficiently continuous that it is impermeable to uncured silicone and impermeable to air. Their case on this was based primarily on the electron micrographs taken by Dr Eklund which they had served under a notice of photographs in December 2010, which ought to have been subject to a notice of experiments but which I admitted in evidence in my judgment on the morning of trial (Mölnlycke Health Care AB v Brightwake Ltd (t/a Advancis Medical) [2011] EWHC 140 (Pat)). A notice should have been served but on the other hand Brightwake had not engaged with the question of whether the old products infringed at all and a repeat did not appear at that stage to be necessary. I stated (paragraph 48) that:

the question of a lack of repeat will go to weight and I shall make it absolutely clear that that is a serious matter. It means that the parties need to be aware that it is possible that if it turns out, having heard the evidence, that a repeat really would have answered various questions, then the court may give these experiments no weight at all.

Dr Turner cross-examined Mr Fabo on these experiments and submitted on the strength of the answers Mr Fabo was able to give (and in some cases not able to give) that the experiments should be given no weight at all.

Dr Turner made the following submissions about Mr Fabo’s evidence on this:

There is considerable force in Dr Turner’s submissions. The evidence as it emerged from Mr Fabo showed that while pictures can look beguilingly simple at first sight, in fact serious questions arise when they are considered carefully. There is no doubt that repeats would have shed significant light on the matter. Crucially repeats would shed light on the extent to which the regions being shown in the pictures are representative across other parts of the samples. One might say Brightwake could themselves have carried out their own electron microscopy but Dr Turner explained that they are not a large multinational business and do not have access to in house electron microscopy expertise. They are an “SME”. I should record that Mölnlycke too do not have in house electron microscopy expertise. They used Dr Eklund of Swerea.

However to give the electron micrographs no weight at all is going too far in my judgment. Where they are corroborated by other evidence then it seems to me they can be relied on without difficulty. So Mr Cotton’s acceptance in evidence that the MBPU fibres effectively melt in the old process is corroborative of the electron micrographs which do indeed appear to show that the fibres have melted. Images of the new products clearly show a speckled region which is obviously the unmelted MBPU fibres as compared to images of the old product which have no speckled region, consistent with the fibres having melted. (Compare images 3 and 4 at bundle B/22 p4 with images 1 and 2 at B/22 p3. I will not include the images in this judgment since it is not necessary to do so.)

However in my judgment the absence of repeats means that the images cannot be given any weight when they stand alone. Mölnlycke contend that the micrographs show that the MBPU in the old product (and for that matter the MBPU/Acrylic in the new product) acts as barrier to the silicone. This is part of their case on permeability. However the micrographs show the presence of silicon atoms inside the acrylic layer of both the old and new products. (Compare image 4 at B/22 p4 and elemental analysis image 24 at B/22 p10 and also image 6 at B/22 p5 and the elemental analysis image 32 B/22 p12. Again annexing these images is unnecessary) In this context the presence of silicon atoms is likely to be due to the presence of silicone. But Mölnlycke’s case is that the melted MBPU and the acrylic adhesive are impermeable to silicone so there should not be silicone in the acrylic. Recognising this Mölnlycke contended that the inconvenient silicone was likely due to contamination when Dr Eklund used the scalpel to cut the material. Cutting through the silicone carried a bit of silicone down onto the acrylic.

This is exactly the kind of thing repeats of the experiments might have helped to address but there are none. For example repeats might have helped to show whether the blobs of silicon(e) were common or a rare occurrence consistent with a bit of contamination. Without a repeat the reasoning is circular. The experiment is supposed to show that no silicone passes through the melted MBPU and/or the acrylic. That is the hypothesis to be tested. But it is falsified by the presence of silicone in the acrylic. So a further ad hoc hypothesis is added – that the silicone is from contamination. But if ad hoc hypotheses can be added to explain a result which falsifies the original hypothesis, the experiment cannot ever prove the hypothesis. Either the original hypothesis is wrong or more experiments are needed. To assert that the original hypothesis is proved is not scientific.

In my judgment the electron micrographs cannot be given weight on the question of whether uncured silicone does or does not pass through the MBPU in either the old or new process. As they stand the unrepeated experiments either falsify that hypothesis or calls for more experiments.

A different point was the presence of silicon atoms in the PU film. There are clearly atoms of silicon in the PU film and Mr Fabo did not know why. They could be due to silica filler in the PU film or perhaps from silicone coated release paper used in the manufacturing process. These explanations may well be sensible ones as Mr Purvis submitted but in the end the issue of silicon in the PU film is a side show. It is hard to see how it has anything to do with the question of whether uncured silicone passes through the MBPU or acrylic because the PU film is not in place at that stage of the process. The PU film is only put on after the silicone has cured.

Apart from the micrographs, there is no evidence that the MBPU layer alone is impermeable to fluid (to the relevant extent) even though the fibres have clearly melted. It has not been tested. Mölnlycke submitted the melted MBPU was a coherent impermeable film. However Mr Fabo’s evidence was that the melted MBPU was permeable not impermeable. It was permeable because of the presence of holes (indeed a hole in the MBPU did appear to be visible in image 6). He maintained that the laminate as a whole was impermeable due to the acrylic but that is a different point. That comes back to approach (c) to the construction of carrier material.

My conclusion on the facts is that if the MBPU alone in either the old or new products is the relevant carrier material, then it is permeable to uncured silicone. It does not satisfy the requirement of claim 6 in relation to fluid permeability (feature (iv)).

I have dealt with the electron micrographs above. I will place no weight on them in respect of permeability to silicone. The experiment designed to prove that the MBPU and acrylic layers together would satisfy claim 6 in relation to feature (iv) (fluid permeability) is Mölnlycke’s Second Notice of Experiments dated 25^th November 2010. A quantity of silicone was poured onto a sample of Brightwake material (MBPU and acrylic adhesive). In one test the sample was held acrylic adhesive side up and the silicone was poured on top of the acrylic. In the other test the sample was held MBPU side up and silicone poured on the MBPU. The report attached as Annex 1 to the notice states that after 10 minutes of having the silicone in place, there was no visible trace of silicone having come through the film. Thus the material appears to be impervious to silicone and satisfies claim 6.

However when the experiments were repeated in the presence of Brightwake’s representatives something different happened. In the case in which silicone was poured on top of the acrylic, silicone was visible on the other (MBPU) side. It was visible because the silicone had wetted the MBPU fibres and the wetted parts look less cloudy than unwetted fibres and therefore show up. The silicone which had passed through the material was also visible as a residue on the scales which were used to weight the sample. So on the face of it the experiment had succeeded in proving the opposite. Silicone passes through the material. Mr Jones for Brightwake exhibited photographs showing this result.

Now Mölnlycke makes a number of points about this. First it points out that the quantity of silicone passing through is small. What are visible are “spots” of silicone. It is clear that the quantity is small but it is also clearly a sufficient quantity for there to be no doubt about its presence. Second it points out that the experiment which more closely resembles real life is the other one in which silicone is poured on the MBPU side. That is because that is the face presented to the silicone in Brightwake’s process. Mr Fabo gave clear evidence that he could not see any silicone on the reverse side in that test and he looked very closely. Brightwake replies that there is no plausible reason why, if silicone can go through one way, it cannot go the other way. The wetting effect which makes the silicone visible can only apply when the MBPU fibres are underneath. Silicone on the acrylic side would be much less easy to see. Finally it points out that the surface of acrylic adhesive which might have had silicone on it was not placed on the scales and so one could not tell if a silicone residue was present by that means.

However Mölnlycke’s main submission on this issue is a broader one: that permeability can only sensibly by judged by reference to Brightwake’s actual manufacturing process. I summarised this part of Mölnlycke’s case above when considering construction. The point is that the depth of silicone and therefore the pressure pushing the silicone through the material is 100 times less in practice at Brightwake than was used in the experiments. So even if the experiments show some permeability, loaded as they are with a sufficient depth of silicone to force it through the membrane, nevertheless the material infringes because in the conditions used by Brightwake, no silicone passes through. For the latter point Mölnlycke rely on Mr Cotton. He was quite clear in his evidence that silicone passing through Brightwake’s material during manufacturing was not a problem. He saw odd spots. Nothing more.

I have already found as a matter of construction that it is not the right approach to interpreting claim 6 to look at the actual process used. Apart from anything else, although the approach happens to make a degree of sense in relation to fluid, it makes no sense at all in relation to the closely related air permeability feature since no air is blown at the material in Brightwake’s actual process. What if someone coated an open mesh through which air could flow freely and then, once the silicone was cured, bonded it to an impermeable PU film and only then cut perforations? Such a wound dressing would infringe claim 6 but asking whether the layer to which uncured silicone was applied in practice was permeable or impermeable to air or silicone during the manufacturing process makes little sense.

Moreover I am not prepared to ignore the patentee’s own Notice of Experiments which were put forward to show that the material satisfies claim 6. The tests are relatively simple sorts of test of precisely the kind which a skilled person would produce in order to test this part of the claim.

The MBPU-acrylic adhesive material tested is clearly not impervious to fluid but is its permeability to be regarded as only slight such that it is still within claim 6? In my judgment an appreciable amount of silicone has passed through the material in the test. The patent explains that the permeability has to be so low that the thick-viscous fluid, i.e. the silicone mixture prior to curing, is unable to run therethrough. In my judgment Mölnlycke’s test shows the opposite. Silicone is able to run through the material. I am aware of no plausible reason why, if it will run one way, it cannot run the other way. The fact that no silicone could be seen that way round may well be because it was less visible for the reasons mentioned already. It is on the margin but I am not satisfied that the MBPU –acrylic tested is within claim 6.

The material tested was the fibrous MBPU based laminate which is part of the new Episil / Episil Absorbent product. For the old products Mölnlycke point out that the melted fibres must make their position stronger. I agree. Mr Fabo thought that this old material would be impermeable. There are no tests on it. Although the legal onus to prove infringement is on Mölnlycke, in my judgment the evidential onus on this product has been shifted to Brightwake. They called no evidence on the point at all. Neither of their experts expressed an opinion on it. I find that the old form of MBPU/acrylic adhesive would satisfy claim 6.

On approach (b) claim 7 goes with claim 6 but separately claim 10 could not be infringed in any event because the carrier material is just MBPU alone.

On approach (c) Mölnlycke contends that the acrylic adhesive layer is a soft plastic film within claim 7. Brightwake submits that acrylic adhesive deformed in a rubbery elastic fashion and did not deform plastically. Thus it was not plastic film. I have rejected this construction of the claim. I do not doubt that acrylic adhesive is rubbery. That is irrelevant. Mr Fabo gave evidence that both MBPU and acrylic were plastics. I accept that evidence. Claim 7 and claim 10 would be infringed by the old Episil/Episil Absorbent products if rejected approach (c) was the right one.

Mr Purvis cross-examined Mr Cotton on the correspondence which arose between the solicitors concerning the old and new Brightwake processes and the Product Description. The original product and process description (PPD) only described the new process and did not mention its predecessor in which the MBPU fibres melt due to heat being applied.

On 24^th September Mayer Brown for Mölnlycke wrote to Wragge & Co for Brightwake enclosing an electron micrograph of Brightwake’s product. Mölnlycke had been told in the original PPD that MBPU was used but they could not identify an MBPU layer in the micrograph. The PPD and micrograph appeared to be inconsistent. The point was that MBPU is fibrous but there were no fibres in the micrograph.

Wragge & Co replied on 29th September 2010. The letter stated “we believe that our client’s Product Description for its Episil and Episil Absorbent products are accurate. At this stage we are unable to offer your any assistance in relation to the micrograph”.

Mr Cotton remembered Mayer Brown’s letter with the micrograph and admitted that it was apparent to him from the micrograph that Mölnlycke must have had a sample of one of the old products with molten MBPU. He had authorised Wragge & Co’s letter of 29th September. Mr Purvis put to him that the letter was disingenuous and Mr Cotton said yes. In re-examination Dr Turner asked Mr Cotton what he understood Mr Purvis to mean by disingenuous. His answer was “was it correct”. I understood Mr Cotton’s evidence in re-examination was that he thought Mr Purvis was asking him whether the Wragge & Co letter was correct and he was accepting the letter was wrong.

It is not necessary to decide whether the letter was or was not disingenuous. In his witness statement Mr Cotton had accepted that the original PPD had not made things clear. He said it was not a deliberate attempt to mislead Mölnlycke and he apologised for the error. Although the matter was eventually sorted out within a relatively short time frame of a few weeks, nevertheless Brightwake did not come out of it with much credit. Mr Cotton clearly knew why it was that Mölnlycke could not see any fibres and yet Mölnlycke had to press hard to obtain the explanation which finally emerged and were only able to get it by sticking to their guns and because they happened to have a sample which was inconsistent with the PPD.

To be valid an invention must be new, which means it must not form part of the state of the art (s1(1)(a) and s2(1) of the 1977 Act). The state of the art includes all matter made available to the public before the priority date (s2(2) of the 1977 Act).

The House of Lords in Synthon BV v SmithKline Beecham plc [2005] UKHL 59, [2006] RPC 10, held that for an item of prior art to deprive a claim of novelty, two requirements must be satisfied: disclosure and enablement. First, the prior art must disclose subject matter which, if performed, would necessarily infringe that claim. As it was put by the Court of Appeal in General Tire and Rubber Co v Firestone Tyre and Rubber Co Ltd [1972] RPC 457 at 486, "[t]he prior inventor must be shown to have planted his flag at the precise destination before the patentee". Second, the prior art must disclose that subject matter sufficiently to enable the skilled addressee to perform it. Mölnlycke submit that Brassington does not disclose anything within claims 6 and 7 and they also submit that even if it does, Brassington does not enable the skilled addressee to produce it. Many of the issues arising on novelty arise again in relation to obviousness but they are distinct and I will treat them separately.

Brassington is a European patent application EP-A- 0 251 810 published on 7^th January 1988 of Johnson & Johnson. The inventor was Nigel Brassington. The document is entitled “Wound dressing” and on the front page the abstract states as follows:-

A wound dressing comprises, in one embodiment, a layer of apertured material, such as a cotton gauze, coated with a tacky silicone gel or a non-tacky silicone elastomer. In an alternative embodiment, the dressing has a tacky silicone gel on one surface and a non-tacky silicone elastomer on the other surface. The gel and elastomer may be formed by crosslinking a mixture of a vinyl-substituted poly(dimethylsiloxane) and a hydride-containing poly(dimethylsiloxane).

Then the first paragraph of the description states:-

This invention relates to dressings such as wound dressings, and more particularly to dressings having a cross-linked silicone coating on a skin-contacting surface thereof.

The text goes on to refer to the range of silicones available from oils to highly cross-linked rigid solids and:

Intermediate in physical properties between these two extremes are silicone elastomers such as gels and rubbers.

Brassington mentions certain previous uses or proposed uses for silicone preparations in wound care and then states at col 1 line 37 -40:-

According to the present invention there is provided a liquid permeable dressing comprising one or more sheets of apertured material coated with a cross-linked silicone

One embodiment is described in which the cross-linked silicone is a “tacky gel” and this dressing is apparently an excellent substitute for tulle gras dressings. The advantages and disadvantages of tulle gras dressings are discussed at length. Advantages include their high degree of conformability and deformability and their tackiness, making the dressing easy to apply because it stays in place due to adhesion to the patients’ skin. Disadvantages include the fact that although the dressing was non-adherent to the wound initially, it becomes “dry”, loses the paraffin coating and adheres to the wound. Another disadvantage is that fibres from the gauze may become incorporated into the wound. After reviewing tulle gras, Brassington continues:

It has now been found that by the use of tacky silicone gels the disadvantages of conventional tulle gras dressings are avoided, while their advantages are retained. In particular, tacky silicone gels provide a coating which is exceptionally non-adherent to wounds, but which is significantly self-adherent. Moreover, such gels are entirely immobile and unaffected by heat or body exudates. This means that dressings according to the invention retain their non-adherent properties even after they have been in place for a substantial period of time, for example several days. Moreover, the fibres of the gauze are effectively encapsulated by the silicone gel, so that fibre loss into the wound is virtually eliminated.

Then an alternative to using tacky silicones is presented:

Dressings according to the present invention may have a cross linked silicone coating which is non-tacky. Such dressings offer an effective alternative to dressings currently available with non-adherent plastics wound contacting layers. In common with dressings containing tacky silicone gels, the non-tacky dressings according to the present invention are highly conformable and flexible, highly non-adherent, relatively inexpensive, unaffected by wound exudate and are virtually Incapable of shedding fibres

It can be seen that Brassington proposes dressings using tacky silicone gels as an alternative to tulle gras and dressings using non-tacky silicone as an alternative to dressing with non-adherent plastic wound contact layers.

Brassington moves on to discuss the silicones which are used to coat the dressings proposed. Tacky gels (for the tulle gras substitutes) are discussed at col 2 line 20 et seq. The non-tacky silicones are discussed at col 2 line 32 onwards. This latter passage states that the non-tacky silicones may be silicone rubbers and refers to the non-tacky silicones as silicone gels too. The discussion of silicones continues until the end of col 4.

At the top of col 5 Brassington describes how to make the dressing. It is formed by coating a sheet of apertured material with a non-crosslinked silicone material and then causing it to cross-link. Various parameters are given relating to curing of the silicones and coating weights for “tacky gels” and “non-tacky crosslinked silicones” are set out.

Next at col 5 line 28 Brassington states:-

The apertured material which forms the substrate for the silicone coating may, if desired, be an apertured plastics film. Alternatively, it may, for example, be a woven or non-woven or knitted mesh, such as a cotton gauze. The effectiveness with which silicone elastomers can encapsulate the fibres of a fabric means that low quality, inexpensive fabrics may be used without sacrificing the quality of the resultant dressing. Moreover, the effectiveness of encapsulation by silicone elastomers means that the apertured material may be printed or dyed with decorative or informative matter with little danger of the ink or dye being released into the wound to which the dressing is applied.

This reference to apertured plastics film forms a key part of Brightwake’s case, to which I will return below.

Brassington continues in the next paragraph to discuss fabric weights and then moves on to discuss the apertures in the material, stating that the size and shape of the apertures are not critical but the apertures should be such that the material can be coated with the silicone gel without them becoming occluded. The apertures preferably have an average diameter of from 0.5 to 4 mm.

Brassington turns at col 5 line 62 to an alternative aspect in which a “tacky gel” is coated on one surface and a “non-tacky elastomer” on the other surface. This dressing:

has the advantage of being convenient to use, in that it will readily remain in position while being secured with a bandage, and it has the further advantage of being non-tacky on the surface which may come into contact with the wearer's clothing.

Brassington describes how to make this dressing by coating one side of gauze with non-tacky silicone elastomer, curing it, then applying a coating of tacky silicone gel to the other side. Alternatively the dressing is made by coating two sheets of support material separately, one with tacky silicone gel and the other with non tacky silicone elastomer. The two sheets can then be glued together.

Brassington mentions some further matters which are not important for present purposes (e.g. using absorbent pads, sterilising with gamma radiation (which Mr Fabo said was not realistic)) and then turns to three examples. Example 1 involves cotton fabric “coated on both surfaces” with a silicone mixture. When cured “the resultant gel was tacky to touch but remained firmly attached to the gauze”. Example 1 is proposed to replace tulle gras. Example 2 coats the same fabric in the same way but with a mixture in different proportions. Once cured the “gel was dry and non-tacky to the touch” and “admirably suited to be used in place of a conventional non-adherent dressing”. Example 3 involves the same gauze as example 1. It is coated on one surface with the silicone mix of example 2 and after curing the other surface is coated with the silicone mix of example 1. After curing the dressing had one tacky and one non-tacky surface.

Prof White had described these examples in his report using the term “gel” for example 1 and the tacky silicone but “elastomer” for the non-tacky silicone. The examples are not written that way. When questioned about it Prof White accepted that differences between gels and elastomers were not his area of expertise.

Finally Brassington includes a number of claims. Claim 10 is a claim to a dressing comprising one or more layers of support material having “a tacky silicone gel coating on one surface thereof and a non-tacky silicone elastomer coating on the other surface”

It is not in dispute that Brassington discloses a wound dressing comprising a perforated carrier material and a layer of hydrophobic silicone gel which lies against the wound surface when the dressing is worn. This is the preamble to claim 6 of the patent in suit and the patent states that such is disclosed in Brassington.

However there are three questions which need to be considered in order to resolve the issues of novelty in terms of disclosure:-

Questions (i) and (iii) relate to the reference to the substrate being an apertured plastics film. It is not in dispute before me that the other substrate materials mentioned in Brassington (such as cotton gauze) cannot satisfy these aspects of claim 6 or claim 7.

Mölnlycke submitted that the reference to apertured plastics film was a throw away line. I will address that in relation to obviousness. For present purposes the fact is that the passage is part of the Brassington disclosure. In my judgment Brassington plainly discloses using an apertured plastics film as the substrate for the wound dressing being discussed.

On issue (i), Mölnlycke submitted that there was no disclosure of a film with the necessary impermeability to satisfy claim 6. It is true of course that Brassington says nothing on that score. Mölnlycke relied on a sentence in Mr Fabo’s first report (paragraph 135) in which he said that while cotton gauze would not be impermeable “however, I would expect most apertured plastics films to have those properties”. Novelty is strict and therefore in my judgment this point alone gives claim 6 novelty. The fact that most films would have the right properties is not sufficient to satisfy the test for anticipation.

On issue (iii) Mölnlycke did not press a submission that the plastics film would not be relatively soft within the meaning of claim 7. Plainly in the context of wound dressings and given the vagueness and wide scope of the expression “relatively soft”, that point was not going to succeed. If claim 6 lacks novelty, so does claim 7.

The real issue in relation to Brassington is whether it discloses a carrier material coated with silicone gel on only one side thereof (issue (ii)). Brightwake submitted that it did precisely that in the very first paragraph of the specification, which simply refers to coating silicone on the skin contacting surface of the dressing. Mölnlycke submitted the document did not disclose coating on one side only, and they refer to various parts of the description and all three examples.

However putting the issue this way disguises the fact that there are two distinct points. A wound dressing with tacky silicone gel on the wound side and non-tacky silicone which is not a silicone gel on the other side is a dressing which would comply with claim 6 (subject to the carrier material being suitably impermeable). So in fact issue (ii) can be addressed in two stages. Does Brassington disclose coating silicone (of any kind) on only one side? In any case, how do the tacky/non-tacky disclosures of Brassington stand with respect to claim 6?

Considering Brassington carefully and in particular considering it as a whole, I believe Mölnlycke are right that Brassington does not disclose coating on one side only. The document as a whole always contemplates coating both sides of the wound dressing with silicone. This can be seen very clearly in all the examples and also from the passage from col 5 line 62 to col 6 line 26. Nowhere does Brassington state in terms that the non-wound contacting face of the dressing need not be coated with silicone.

The high points of Brightwake’s case are the first paragraph which refers to a coating on the wound contacting side and the top of col 5 which refers to “coating a sheet of apertured material” without saying coating both sides. In my judgment it is only with hindsight that one reads either of these passages as a disclosure of a dressing coated only on one side. A skilled reader reading Brassington when it was published (in 1988) or at the priority date (1992) would not be taught to leave one side of the dressing uncoated with silicone.

Brassington plainly discloses a wound dressing which has silicones with different properties in either face. Tacky on one side and non-tacky on the other. This can be seen in the abstract (2nd sentence), at col 5 line 62 – col 6 line 26, Example 3 and claim 10. In two places gauze is mentioned as the substrate (col 6 line 9 and example 3) but otherwise the disclosures are general. That takes one to col 5 line 28 – 32 in which the substrates proposed are apertured plastics film or alternatively woven or non-woven or knitted mesh such as cotton gauze.

At this point I bear in mind the approach to novelty set out by the Court of Appeal in Dr Reddy's Laboratories (UK) Ltd v Eli Lilly & Company Ltd [2009] EWCA Civ 1362 noting that the general does not disclose the particular and that what is required for disclosure is an individualised description. A skilled reader would see that in terms of what Brassington teaches them to do, all three general kinds of coating which are disclosed – tacky both sides, non-tacky both sides and tacky/non-tacky on opposite sides - are equally applicable to a substrate of apertured plastics film as they are to the alternatives such as gauze. In my judgment a two sided tacky/non-tacky wound dressing in which the substrate is an apertured plastic film is disclosed by Brassington.

Would such a structure satisfy feature (v) of claim 6 (silicone gel on only one side)? There is no doubt that Brassington frequently refers to the non-tacky silicone coating as an elastomer in a way which is plainly intended to draw a distinction between elastomer and gel. That can be seen in the abstract, at col 5 line 62 – col 6 line 26 and in claim 10. However it is also the case that in other places Brassington refers to the non-tacky silicone as a gel - see example 2, col 3 line 35 and col 4 line 23. One can perhaps see why this has happened given the sentence in Brassington at col 1 line 13 quoted above which gives gels and rubbers both as examples of silicone elastomers with intermediate physical properties between the extremes of oils and rigid solids.

However although one might expect the words to have the same meaning in both documents, it is not necessarily the case that Brassington’s use of the term gel is co-extensive with the scope of “gel” in claim 6. I must decide what (if anything) Brassington discloses as a matter of fact. Once that is done, the thing disclosed is either within the claim or it is not, regardless of what Brassington called it. The matter is further complicated by the fact that the patent in suit refers back to Brassington but I have dealt with that above in the section on construction.

In my judgment Brassington would be understood by a skilled reader at the relevant time as a document which was not concerned with the niceties of whether certain silicones are strictly to be called gels, elastomers or rubbers. The distinction Brassington was concerned about was the distinction between tacky and non-tacky silicones. So when Brassington wanted to emphasise the difference he referred to tacky silicone gels as opposed to non-tacky silicone elastomers. That distinction would be familiar to the skilled person because gels are usually tacky and elastomers are usually not tacky although there is a degree of overlap.

In my judgment the skilled reader would understand that Brassington recognised the difference between materials which are gels and are normally tacky but may not be and other forms of silicone which are normally non-tacky and are not gels. Brassington often mentions the term “cross-linked” in the particular context of the non-tacky silicones. This reflects the skilled person’s understanding that a gel is a state in between an uncured fluid and a fully cross-linked elastomer. It would be clear to the skilled reader that the tacky materials and the non-tacky materials proposed by Brassington are at points in the continuum between uncured fluid and fully cross-linked elastomer. The terminology is not exact but the concepts are clear.

The thrust of this aspect of Brassington’s disclosure is to employ tacky silicone gels on one side and non-tacky materials on the other side. In my judgment Brassington can be regarded as disclosing a continuum of non-tacky silicones ranging from gels to more cross-linked silicone elastomers, which Brassington calls silicone rubbers and which are not gels on any view. Although the skilled person would not be aware of claim 6 of course, in fact the tacky gel on the wound contact side would be a “silicone gel” in claim 6 while a more cross-linked non-tacky silicone rubber would not be a silicone gel as referred to in claim 6. However bearing in mind Dr Reddy's v Eli Lilly (above) in my judgment an individualised disclosure of a combination of plastic film as the substrate, tacky silicone gel on the wound side and non-tacky silicone rubber (and not gel) on the other side is not in Brassington.

In summary, Brassington discloses a wound dressing with features (i), (ii) and (iii) of claim 6. The relevant wound dressing is one with an apertured plastics film carrier material, tacky silicone gel on the wound contacting side and non-tacky silicone on the other. Features (iv) and (v) are not disclosed in combination with the others and thus claim 6 is novel. Nevertheless in deference to the arguments I will address the issues of enablement in any event before turning to obviousness.

A key aspect of Mölnlycke’s case about Brassington is that the teaching concerned with coating apertured plastic films is not enabling. There was no difficulty coating gauze with silicone in such a way that the whole thing is coated and the fibres are encapsulated with silicone. However Mölnlycke submitted that coating an apertured plastics film and still keeping the holes unclogged with silicone was more difficult. Mölnlycke submitted that Mr Fabo could not manage it until he invented the clever air blowing method of claim 1 of the patent in suit. Mölnlycke performed experiments to show that Brassington was non-enabling. This consisted of a Notice of Experiments annexing a report of Dr Dillingham and a partial repeat conducted at Imperial College by Clementine Walker under the supervision of Prof Alford.

In Synthon Lord Hoffmann explained that enablement means that the ordinary skilled person would have been able to perform the invention disclosed. He pointed out that the concept of enablement is also used in the context of the law of sufficiency of disclosure and cited the judgment of Buckley LJ in Valensi v British Radio Corp [1973] RPC 337 and the judgment of Lloyd LJ in Mentor v Hollister [1993] RPC 7. Lord Hoffmann held that the tests for enablement and sufficiency are the same albeit that there may be differences in their application to the facts given the differing circumstances.

There is no pithy summary of the test for sufficiency of disclosure no doubt because it would be impossible to cater for the variety of factual situations which may arise. The skilled person is not expected to exercise any degree of invention nor any prolonged research, inquiry or experiment (Valensi, cited in Synthon). He must be prepared to display a reasonable degree of skill and common knowledge in the art in making trials. The use of the term “routine trials” by Aldous J at first instance in Mentor v Hollister was criticised by counsel in the Court of Appeal but Lloyd LJ rejected that criticism and stated that it may provide a surer text than the negative test proposed in Valensi of an absence of prolonged research, enquiry or experiment. However in Halliburton [2006] EWCA 1715 (paragraphs 17 and 18) the Court of Appeal made the point that the setting of a gigantic project, even if merely routine, did not satisfy the test.

Although Mölnlycke had put forward experiments to prove the negative, they submitted that in fact the onus of proof was on the person attacking validity - i.e. Brightwake. Mölnlycke pointed out that Brightwake had performed no experiment to prove that Brassington was enabling. In response Brightwake relied on the judgment of Laddie J in Evans Medical Ltd’s Patent [1998] RPC 517 at 533 line 5-11. That case was in fact about priority but both sides before me agreed that as long as one got the parties the right way round, the distinction was irrelevant. The passage from Laddie J with amendments to make it fit with the present case is:-

Although the onus is on [Brightwake], in a normal case the court will proceed on the basis that the technical results set out in the [prior art] document can be achieved as asserted. It is enough if [Brightwake] asserts that the instructions in the [prior art] document work to produce the results claimed for them. A claim to [lack of novelty] is, implicitly, such an assertion of enablement. If that is not effectively challenged then [Brightwake] has done enough.

It follows that [Mölnlycke] should do more than merely issue a challenge to [anticipation]. He must explain the manner in which he says there is failure to enable. This should be set out in his pleadings. He will have to support his assertions by evidence. The court should be able to proceed on the basis that the experimental data in the [prior art] document is not only right but reasonably repeatable. Although the onus remains on [Brightwake], the evidential burden shifts to [Mölnlycke]. In some cases he may not be able to discharge it without supporting experiments.

Mr Purvis submitted that this was referring to a case in which the document states that an experiment or procedure of some kind has actually been carried out and particular results or data have been in fact been achieved. Therefore while it might apply to the examples in Brassington it has no application to the other parts of the disclosure. Mr Purvis is right about what Laddie J was referring to on the facts of the case before him but it seems to me the principle is wider than Mr Purvis submits. Each case will need to be decided on its own facts. Evans Medical was about complex protein purification techniques in which the protein being purified was described as adenylate cyclase but in fact was something else. It was actually pertactin. The misdescription was found in the end to throw the skilled reader off the scent if they tried to repeat the work.

Brassington is concerned with coating substrates with silicone. There is no indication in Brassington that this is especially problematic. The document specifically teaches that the sizes and shapes of the apertures are not critical and should be such that the material can be coated without occluding them. Bearing in mind the nature of the technology and the way in which Brassington expresses itself on the issue, in my judgment Brassington can be taken as an assertion that the products proposed in the document can indeed be made. In this case therefore the evidential onus shifts to Mölnlycke to challenge enablement. I will decide this issue based on the evidence before me. If I need to have recourse to the evidential or legal onus to resolve the matter I will return to it after reviewing the evidence.

The evidence relating to enablement was:-

Mölnlycke relied principally on Mr Fabo’s experience and the report of Dr Dillingham. Brightwake pointed out that Mölnlycke did not place much reliance on the repeats by Ms Walker and Prof Alford. Brightwake submitted that those individuals had been airbrushed out of the case altogether. Brightwake submitted that in fact the repeats had proved the opposite of what Mölnlycke intended. They showed that even very rough and ready techniques could coat silicone on a plastic film without clogging the holes. Brightwake also took various points on Mr Fabo’s evidence and Mölnlycke’s experimental evidence. Brightwake’s positive case that Brassington was enabling was based on the evidence of Dr Meirowitz that there were many techniques available. His opinion was that a skilled person would be able to carry out the coating without clogging.

I will deal with each piece of evidence in turn.

Mr Fabo first came up with the idea of using silicone on a wound dressing in the 1980s. He wanted a wound contact layer which would not adhere to the wound bed. After trying both silicone and PTFE he gave up but then found a cup of sticky messy material in the room of a colleague who was retiring. It turned out to be a silicone gel made from a Dow Corning kit. When testing the material Mr Fabo found that it had a low adhesion to wounds and wound exudate but adhered to dry skin enough to hold the dressing in place whilst a pad or bandage was put on. The gel was not strong enough on its own so Mr Fabo coated it on a textile mesh. The mesh had perforations to allow wound exudate to pass through and the silicone gel could adhere to itself through the fibres. This led to the Fabo prior art patent and to Mölnlycke’s Mepitel product.

During the final stages of development of Mepitel (it was launched in Sweden in 1990) Mr Fabo decided to create what he called “the perfect unitary wound dressing using silicone gel”. He wanted something which would adhere to dry skin and which was tackier than the Mepitel product so that it would remain in place in use but be easily removable. He developed prototypes using a gel supplied by Wacker. Apparently he encountered a problem with affixing a barrier layer on the silicone gel which was on top of the product and this led him to the desire to coat only the wound contact side with silicone gel. This reasoning is not recorded in the patent nor is the idea that the dressing described in the patent could be used as a component in a unitary wound dressing with a barrier layer.

In any event when Mr Fabo tried coating the film on one side he said either the perforations clogged up or the silicone spread to the other side or (as happened nearly always) both. Mr Fabo also tried coating an unperforated film and then making holes but that did not work. I will return to that work later below. Eventually he developed a process which did work, i.e. the air blowing method of claim 1.

Mr Fabo did make notes when he performed this work nearly 20 years ago but they have not survived. Brightwake criticised the way in which Mölnlycke’s solicitors had handled this aspect of disclosure and it is fair to say that with the benefit of hearing Mr Fabo in the witness box, it is clear that Mayer Brown’s assertion that there never were any laboratory notebooks was not as careful as it could have been since Mr Fabo confirmed he had kept loose leaf laboratory notes. However there is nothing sinister in the fact that such documents have not survived to this day. It does mean however that all Mr Fabo has to go on is his own recollection. There is one contemporary document – the formal report of invention document from December 1991 – but that does not record the failures, only the success.

In cross-examination when asked about his memory of the failures Mr Fabo maintained that he had a memory of “some of” his failures and successes. Dr Turner submitted that his evidence about what he did 20 years ago needed to be treated with caution in that light. I have no difficulty in accepting Mr Fabo’s general evidence that he tried to make a perforated polyurethane film coated on one side with tacky silicone gel and had genuine difficulties in doing so. However in my judgment his evidence cannot be taken much further than that. He was not trying to put Brassington into practice. For example Brassington specifically teaches that the size and shape of the apertures is not critical and they should be chosen to ensure coating without occlusion (col 5 line 49-53). Mr Fabo never mentions changing the size and shape of the apertures he had. There is no evidence Mr Fabo even wanted to change the apertures or felt he could do so.

In November 2009 Dr Dillingham produced a report which recorded his efforts to coat perforated urethane sheets using the descriptions in Brassington. He was picking up specifically the passage in Brassington from col 5 line 62 to col 6 line 26. His conclusions included a statement that it was not possible to coat only one side because the silicone ran through and covered the entire urethane surface and it was not possible to prevent occlusion of the majority of the perforations in any experiment. So Mölnlycke submit Dr Dillingham’s report provides evidence that Brassington is non-enabling.

The report had not been prepared for the purpose of this litigation but had been prepared for other purposes. It was the subject of Mölnlycke’s first notice of experiments. However when repeats came to be organised Mölnlycke did not attempt to repeat precisely what Dr Dillingham had done. The repeats did not purport to repeat some parts of Dr Dillingham’s work at all and in other respects carried out steps in a different way. I will deal with that later. The repeats were to be performed in accordance with a repeat protocol served on 8^th October 2010. Once the repeats had been completed Brightwake applied to Arnold J on 29^th November 2011 for an order debarring Mölnlycke from relying on the unrepeated parts of the notice (i.e. the unrepeated parts of the Dillingham report). Arnold J understood from Mölnlycke that notwithstanding the notice, the unrepeated aspects were really in the nature of background experiments or workup experiments leading to the key experiments which are the experiments which were repeated. Understandably in the circumstances if I may say so, Arnold J did not rule out the unrepeated evidence. He did however emphasise that there was room for argument as to weight and an unrepeated experiment might be given considerable weight, some weight or no weight whatsoever in the circumstances.

In the course of getting to the judgment of Arnold J the parties had been in correspondence about the notice and the Dillingham report. In the course of that correspondence and in a witness statement of Mr Ian Wood, their solicitor, Mölnlycke had made it clear that it did not rely at all on some parts of Dillingham. This was not a matter in which Arnold J had to rule.

Thus before me at trial I have a report of Dr Dillingham which contains (a) material on which Mölnlycke stated in correspondence they would not be relying on at all, (b) material which was not offered for repetition but is relied on and (c) material which was repeated albeit with modifications. In case there was any doubt I checked with counsel that these three categories existed (Day 5/533). Category (a) includes spraying work and certain viscosity measurements. Neither of these are relied on by Mölnlycke (see Ian Wood’s witness statement paragraphs 18 and 25). Category (b) apparently includes calculations and experiments on areal density. I think this must be the material in bundle B/11 page 11 under the heading “calibration of areal density” and including a figure 6. I say that based on the transcript before Arnold J on 29^th November 2010. In category (c) is the work using a coater called a bird film applicator. When Prof Alford and Ms Walker came to apply the coat they used a ruler to spread the silicone instead.

Mölnlycke made no submission to me relying on areal density calculations of experiments and I will place no weight on them.

The real point is that Mölnlycke rely on Dr Dillingham’s bird film applicator experiments and his conclusion that the work failed. It was not repeated at Imperial because there a somewhat different approach was taken, but the evidence is admissible and the lack of a repeat goes to weight. I am bound to say the way in which Mölnlycke relied on this Dillingham bird film applicator work before me did not make them “work up” or “background” experiments at all. They were at the forefront of Mölnlycke’s case at trial.

Brightwake submitted that Dr Dillingham’s experiments were “litigation experiments in the derogatory sense”. This is a reference to criticism of contrived experiments by Jacob LJ in SKB v Apotex [2005] FSR 23 at para 77-81 (and also SKB’s Patent (No 2) [2003] RPC 33).

There is no suggestion that Dr Dillingham’s report is not a faithful and reliable statement of what happened when he did what he did. However that is not the issue. The question is whether Dr Dillingham’s report is evidence of what a skilled person would do to put Brassington into practice. As to this the sequence of events was as follows:

The degree of involvement of the lawyers, the fact that experiments had gone on before the protocol was fixed, and the fact that Dr Dillingham’s efforts were constrained in relation to the perforations (which is the one thing Brassington specifically refers to in relation to clogging as being a parameter which is not critical and can therefore be changed), when taken together lead to the conclusion that I cannot place reliance on Dr Dillingham’s experiments as representative of what a skilled person would do to put Brassington into practice. To rely on the experiments I would have to be satisfied that they were not contrived. I am not satisfied.

Under the supervision of Prof Alford, Clementine Walker a postgraduate student carried out the repeats on 15^th November 2010. Brightwake’s patent attorney Mr Jones exhibited a video of the occasion and certain stills from the video were put in the X bundle. Dr Meirowitz criticised these experiments:-

Prof Clarson for Mölnlycke had been shown Dr Dillingham’s report and gave evidence about that, but he was not aware of the repeated experiments at all and gave no evidence about them. Dr Meirowitz was not cross-examined on his evidence about the repeats and I accept it. I find that the repeated experiments are too crude to be representative of what a skilled person would do if they were seeking to put Brassington into practice. They do not show that Brassington cannot be made to work.

However Brightwake submit that in fact despite their crude nature, the repeats actually demonstrated that Brassington is enabling. Brightwake’s best point is experiment 9 of the repeats. In this test a film of Mölnlycke PU (polyurethane) with 1mm circular perforations was coated with silicone “mixture 2” by being “fully supported”. Fully supported means the film was not suspended but was placed in full contact with an acrylic sheet. Mixtures 1 and 2 consisted of different relative amounts of a two-part silicone (A plus B). Mixture 1 is described in the repeat protocol as “The ‘tacky silicone gel’ described in Brassington”. It consisted of 70% B and 30% A. Mixture 2 is described in the repeat protocol as “The ‘non-tacky silicone elastomer’ rubber obtained by blending equal parts by weight of the two components”.

So experiment 9 is non-tacky silicone elastomer rubber applied to one side of perforated PU film and was put forward by Mölnlycke as relevant to the question of putting Brassington into practice. Brightwake point out that the perforations in this material were unclogged (only one clogged hole in 120 holes) and also that although some silicone did spill out on the reverse side around the holes, it remained in the form of islands around the holes and did not join up to form a continuous layer. They submitted that this shows that coating on only one side with silicone can be done by a skilled person putting Brassington into practice even very crudely. The carrier material is perforated. One clogged hole cannot matter. The silicone is coated only on one side.

Mr Purvis submitted that in this instance the silicone coating was on both sides of the film. I am bound to say that the degree of coverage of the surface by the islands of silicone visible on the reverse side of the film here resembles the “spots” of silicone found to have leaked through the MBPU –acrylic material which Mölnlycke tested in their infringement experiments to show that it was impermeable to silicone fluid. In my judgment, in neither case is the quantity of silicone on the reverse side trivial.

I doubt that the islands of silicone would be a coating as required by claim 6. It is not necessary to resolve that issue because I am not concerned at this stage with a skilled person aiming to produce a wound dressing coated with silicone only on one side in the light of Brassington. In my judgment regardless of whether the silicone islands are to be regarded as a coating in their own right, the fact that an effort as crude as this gets as far as it has done is supportive of a conclusion that Brassington overall is an enabling disclosure.

I asked Mr Purvis what his position was as to whether the non-tacky silicone used in his client’s experiment 9 was a silicone gel within claim 6. A note was going to be sent after the trial. When the confidential draft judgment was given to the parties’ representatives on 22^nd February 2011 the draft stated that no note (so far) had been received but that I did not think it mattered. In fact the court had received a note on 16^th February explaining Mölnlycke’s position. As a result of an administrative oversight I had not seen the note. I saw it on 24^th February 2011. Mölnlycke’s position essentially is that it relies on Dr Dillingham’s evidence that this was the most likely formulation to produce a non-tacky elastomer as described by Brassington. Mölnlycke do not admit the silicone is a gel within claim 6 and contend that Brightwake did not discharge the burden on it to prove that it was. The note does not cause me to alter my judgment.

Prof Clarson’s opinion in his report was that a silicone specialist would not have been able to coat an apertured plastics film on only one side. He did not think it could be done (without invention) without avoiding the silicone precursor spreading onto the other side or occluding the perforations. Much of his report was based on Dr Dillingham’s report which he said reinforced his initial view. My conclusions about that report involve no criticism of Prof Clarson but they do mean that much of his evidence becomes of little value.

Absent the Dillingham report, Prof Clarson’s view was that the silicone precursor mixture described in Brassington was very flowable and could not be contained on one side of the film. He also expected that apertures of the size referred to in Brassington – up to 4mm – would become occluded at the loading densities specified in Brassington. However although shown the Dillingham report, Prof Clarson had not been shown the results of Mölnlycke’s repeat experiments. These are the ones Brightwake contend show that, despite their crude nature, Brassington is enabling. Experiment 9 does indeed show that the 1mm holes in the polyurethane sheet in question was not occluded by mixture 2. There is some silicone on the reverse side but not a great deal. Mixture 2 was the non-tacky silicone rubber precursor. Prof Clarson’s opinion that Brassington would not work did not distinguish between the different precursors and in my judgment Mölnlycke’s repeats do undermine his opinion. It would have been much better if Mölnlycke had shown their expert witness this material for him to comment. But they did not.

In cross-examination Prof Clarson’s evidence was that if someone had brought Brassington to him he would have said that some trial and error was needed to find out what coating technologies were appropriate. There were various parameters for a skilled person to adjust including the A/B ratio in the precursor, viscosity (to some extent), loading, the type of plastic substrate and the sizes of the apertures. The Professor maintained the view that the skilled person would not have any certainty in advance of testing that he could get a product with unoccluded apertures.

Dr Meirowitz gave evidence of numerous techniques for coating silicone which were common general knowledge. His opinion was that knife coating and spraying the silicone were techniques which would be used to coat silicone on plastics film in the present context. If the apertures were occluded their size would be adjusted. The skilled person would also consider adjusting the viscosity. Dr Meirowitz accepted that he had not tried to coat silicone on a film with apertures of the size described in Brassington although he had coated other plastics films with silicone.

Dr Meirowitz also gave evidence about the use of a vacuum system but Prof Clarson thought that would cause problems. I will not place reliance on the vacuum proposal.

The high point of Mr Purvis’s cross-examination of Dr Meirowitz was an interchange relating to Dr Dillingham’s report as follows:

Q. So you have never tried to apply it to a film such as Brassington describes, with apertures of that size, correct?

A. With apertures of that size, no.

Q. So you cannot say from your own experience whether the problems that Dr. Dillingham experienced are problems that would be generally experienced by anyone who was trying to do it or not, can you?

A. Yes, actually I think I can, in that when I looked at the report there was one attempt made with 1 mm holes with one type of RTV at one viscosity, using a bird feeder applicator on a non-secured film, which would pretty much be all things that could be rectified. So before I would look at that and say this cannot be done, there are many variables that are non-inventive.

Q. But you did not actually try any of them, did you?

A. I was not asked to.

Q. We will never know, will we? The only person who has ever actually tried it failed. Correct?

A.

Yes.

[Day 4/500]

Mölnlycke laid great emphasis on the answer at the end of this passage. However it is based on Dr Dillingham’s report, which I do not regard as reliable evidence of the skilled person actually trying Brassington.

There was also a point about spraying. One of the particular techniques Dr Meirowitz thought would be employed was spraying the silicone precursor. Dr Dillingham’s report had mentioned in a single sentence that a spraying technique had been tried initially but atomisation was poor and areal density was not controllable. However well before the trial Mölnlycke had made clear that they were not relying on the spraying aspect of Dr Dillingham’s report.

In cross-examination Dr Dillingham was asked by Brightwake’s counsel Dr Turner why he had chosen the doctor blade technique in the bird film applicator to apply the silicone. He replied that his initial thought had been to spray but he and his team were unable to find a set of conditions or apparatus that would apply silicone properly. Counsel continued, pointing out to Dr Dillingham that the spray work must have been done before the draft protocol was arrived at and putting to Dr Dillingham that there were numerous other coating techniques which could have been arrived at as well as spraying and the doctor blade approach. Dr Dillingham agreed. On this basis Mr Purvis put Dr Dillingham’s spraying evidence to Dr Meirowitz in cross-examination despite Mölnlycke having indicated they were not relying on it. No objection was taken until the point was raised in closing. Dr Meirowitz did not feel he could comment given the lack of detail about this in Dr Dillingham’s report.

The evidence that Dr Dillingham tried spraying and did not succeed is in the case for what it is worth. I have no doubt the statement about it is a faithful record of what was done but I will not rely on it as evidence of putting Brassington into practice for the same reason as the rest of the report. In any event it is not described in sufficient detail for it to undermine Dr Meirowitz’s opinion that spraying would be likely to produce suitable application results.

The question of whether Brassington is enabling in relation to the coating of apertured plastics films is borderline in my judgment. Mr Fabo had some difficulty in making a plastic film coated with silicone on one side. Applying silicone to apertured plastics film substrates like those proposed by Brassington will almost certainly not work well first time. However it is the kind of task which persons skilled in the art with experience of silicone are familiar with. In this art, if something does not work first time, some trial and error will be employed. This involves only standard techniques in the art: knife/doctor blade coating and/or spraying. The parameters to adjust would be familiar ones to a skilled person. I doubt it would be a prolonged exercise and it would not be the kind of work usually characterised as research. The fact that even the crude experiments at Imperial produced a film which was not occluded, supports the proposition that Brassington can be put into practice. However a satisfactory test has not been done. In terms of the opinions of the experts, I prefer the evidence of Dr Meirowitz on the issue of enablement.

On balance in my judgment Brassington is an enabling disclosure of what it discloses, namely a wound dressing made by coating an apertured plastics film with tacky silicone gel on the wound contacting side and non-tacky silicone on the other.

Section 3 of the 1977 Act provides that an invention shall be taken to involve an inventive step if it is not obvious to a person skilled in the art having regard to any matter which forms part of the state of the art by virtue of s2(2) of the 1977 Act. A structured approach to the assessment of obviousness was set out by the Court of Appeal in Windsurfing International Inc v Tabur Marine [1985] RPC 59 and was adjusted somewhat by Jacob LJ in Pozzoli v BDMO [2007] EWCA Civ 588, [2007] FSR 37. It is:

Mr Purvis submitted that this case was a kind of “obvious to try” case and therefore the defendant has to prove that “it is more or less self evident that what is being tested ought to work” per Jacob LJ in Saint-Gobain [2005] EWCA 177 at para 28. In Conor v Angiotech [2008] UKHL 49, [2008] RPC 28 the House of Lords considered the issue of an need for an expectation of success in the context of arguments about things being “obvious to try”. There Lord Hoffmann (with whom the others of their Lordships agreed) approved the following statement of Kitchin J made in Generics v Lundbeck [2007] RPC 32:

The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success.

In Synthon the House of Lords took care to distinguish between the concepts of disclosure and enablement from the point of view of novelty. A similar distinction can arise in relation to obviousness in the sense that there may be a thing which is obvious to think of but which may turn out to require an inventive step to make. In that case the claim would not be obvious. Otherwise a lower standard would be required for inventive step than for novelty.

There is a difference in principle between the following two cases, both of which start with a disclosure in a document. The disclosure may or may not be an enabling one in the sense that the person skilled in the art is able to put the disclosure into practice without undue effort. If it is enabling then a later claim to that thing will lack novelty. But even if the disclosure is not enabling, it may or may not require an inventive step on the part of the skilled person to put the disclosure into practice. If putting the disclosure into practice does not involve an inventive step, then a later claim may or may not be novel but it will be invalid for obviousness. Although in very many cases these two concepts will be very similar and will inevitably involve very similar factual considerations, they are not the same.

In the context of inventive step, the cases on enablement and sufficiency which discuss how much effort a skilled person should put into the task before a document ceases to be an enabling disclosure need to be kept in their proper place. Their proper place is in the context of novelty and sufficiency of disclosure. They are not concerned with obviousness.

I have addressed the person skilled in the art and common general knowledge above. I have construed claim 6. This is not a case in which there is any need to abstract out some separate inventive concept. The differences between claim 6 and Brassington are features (iv) and (v).

One of the points in relation to Brassington is whether it makes coating silicone on one side obvious. I will deal with that after I have considered whether Brassington renders claims 6, 7 and 10 obvious in any event.

The general thrust of Brassington is to produce a wound dressing comprising a layer of apertured material, such as cotton gauze, coated with tacky silicone gel or non-tacky silicone elastomer. The document expressly contemplates coating one side with tacky silicone gel and the other side with non-tacky silicone elastomer. The tacky gel goes on the wound contacting side.

The passage at col 5 line 28 states that the substrate may be an apertured plastics film. Mölnlycke submitted that this statement would be regarded by a skilled reader as a “throw away line”. Although irrelevant for novelty (if it is disclosed it is disclosed, throw away line or not) the point can have a bearing on inventive step and needs to be considered.

A reader would not regard the statement as speculative. Apertured plastics films were used in wound dressings already and formed part of the common general knowledge (e.g. Melolin). Plastics films without apertures were also used in wound dressings already as part of the common general knowledge (e.g. OPSITE). Brassington expressly mentioned dressings with plastic wound contacting layers at col 2 line 58. It is perfectly true that examples 1 to 3 use cotton fabric/gauze, and gauze is mentioned elsewhere too but the skilled reader would see the relevant part of the document as a clear teaching about the kind of materials which can be used as the substrate for the wound dressing described. It would be understood to be equally applicable to all of the three arrangements of silicone described in Brassington – tacky silicone gel on both sides, non-tacky silicone on both sides, and tacky/non tacky on opposite sides.

The sorts of plastics films which would be obvious to use as a substrate would be films such as the kind used in the products which were common general knowledge e.g. OPSITE, Melolin and Release. Polyurethane film would be obvious. These films will in fact be impermeable to air and fluid within the requirements of claim 6.

Brassington clearly proposes using silicones in a wound dressing and is a document emanating from a major health care company Johnson & Johnson. It is a serious proposal. Although the skilled person probably would have been aware of the silicone breast implant litigation in the USA it would not be a relevant deterrent.

The tacky silicone gel to be used on the wound contact side would satisfy claim 6 (“silicone gel”).

What kind of silicone would be used on the outside of the dressing? Brassington expressly gives the skilled reader a solid motivation to coat only the wound facing side with tacky silicone gel and put non-tacky silicone on the outside (col 6 lines 2-7). When considering the disclosure of Brassington in the novelty section I held that Brassington can be regarded as disclosing a continuum of non-tacky silicones from gels to more cross-linked silicone elastomers which are not within the compass of silicone gel in claim 6 on any view. Brassington emphasises that the silicones used to form the non-tacky dressings are preferably rather more robust than the tacky gels and may for example be silicone rubbers (col 3 line 32). The skilled team’s common general knowledge tells them that, in general, the degree of cross-linking affects the tackiness of silicone and whether a product has gel like, elastomeric or resin properties depends on the degree of cross-linking too. Cross-linking is not the only parameter by any means but this reinforces the tendency to go for a more cross-linked silicone elastomer rubber rather than a gel in order to make a non-tacky product. Moreover the silicone N-A product was part of the common general knowledge as at 1992. This wound dressing employs a non-tacky silicone which is not a gel.

In my judgment employing a silicone rubber as the non-tacky silicone in the tacky/non-tacky dressing would be entirely obvious. It is really no more than putting the relevant part of Brassington into practice. Such a silicone would not be a silicone gel within claim 6. I do not doubt that another obvious way forward over Brassington would be to use a non-tacky silicone gel, after all Brassington says as much as well. However that does not detract from the obviousness of employing a silicone rubber for the non-tacky component.

Accordingly in my judgment it would be obvious for a skilled team to propose making a wound dressing with tacky silicone gel on the wound side, a different non-tacky silicone on the outer face which would not be a silicone gel and a carrier material made of an apertured plastic film like polyurethane. This proposed product would satisfy claim 6. This is akin to a finding that such a product would be “obvious to try” in the sense of being obvious to try to make and so two further factors need to be considered. First would there be sufficient doubt that such a product could be made to put off a skilled team from even trying and secondly, even if they thought it was worth making, would the skilled team in fact succeed without invention?

The skilled team would not be put off from proposing such a product because of any a priori doubt about being able to make it. Prof Clarson’s evidence was that if a person came to him with an apertured plastic film and a silicone kit he would not say “this cannot be done”. He would need to do some tests. In my judgment that reflects the position of the skilled person (or team). There is nothing intrinsically difficult about the proposed product which would mean the skilled team would disregard the proposal as untenable before even embarking on making it. They would have every prospect that the product would be readily produced.

So the product is obvious to conceive but it would remain a mere proposal unless the skilled team can actually make it without the exercise of invention.

Brightwake submit that even if problems were encountered of the kind discussed in the enablement section above in dealing with novelty, the skilled person would have no trouble making the product by coating the plastic first and then cut the apertures second.

Mölnlycke point out that Brassington specifically states that the dressings are formed by coating a sheet of apertured material with uncured silicone and then cross-linking (col 5 line 1-3). For this reason the expedient of cutting holes in a plastics film already coated with silicone has formed no part of my judgment on novelty. I agree with Mölnlycke that the only techniques disclosed in Brassington itself involve apertures first, coating second. To do anything else is to go beyond the disclosure of the document at least to some extent. On inventive step this point is a factor to take into account but it is not determinative.

Mr Fabo, in his work before he made the invention of the air blowing process, had tried making holes after the silicone had cured but did not succeed to his satisfaction. He tried using a punch, using a punch-like biopsy tool and using hot needles. With punches the chads kept sticking to the surface of the dressing, blocking the tool and with needles the silicone gel would flow back once the needle was removed. However in the absence of documents relating to this work all I have to go on is Mr Fabo’s memory for the events nearly 20 years ago. I have no doubt he tried this and did not succeed. I have no doubt it involved the equipment he mentioned. However I am not satisfied that there is sufficient detail available today in order to place any further weight on Mr Fabo’s memory. For example I am not satisfied as to the extent of this part of the work, how much time and effort it involved, precisely what was tried, what constraints Mr Fabo was working under (including for example whether the aperture size was a given) and when in the process Mr Fabo came up with his air blowing method and therefore did not need an alternative.

Dr Meirowitz thought it would be obvious to make holes in the coated plastic film after the silicone had cured and mentioned a nip roll as a common device for perforating substrates. If tacky silicone sticking to the roll was a problem then a temporary liner placed on the silicone could be employed. Brightwake make their products by using a temporary liner on the silicone and punching out the holes after the silicone has cured. Mr Fabo himself did not think there was anything innovative in Brightwake’s method of manufacture. I bear in mind that he was asked that question having regard to his own patent in suit but even so that does not make his answer irrelevant. The only method in the patent is a quite different air blowing method.

Prof Clarson’s opinion was that he did not think a needle could be used to make the holes but he did not address the matter more widely than that in any detail. When Brightwake’s manufacturing method was put to him he too agreed that there was nothing conceptually clever about putting something over the silicone and punching holes in it.

There was some evidence about lasers or electron beams but I was not satisfied that those proposals were obvious.

In my judgment it would be perfectly obvious in the light of Brassington to make the wound dressing by coating the plastics film first and then cutting holes in it. It is a simple technique which the skilled team would expect to work and which would work.

Mr Purvis submitted that Brightwake’s argument was the familiar impermissible step by step approach deprecated in Technograph. In my judgment this reasoning is not vulnerable to a “Technograph” submission. It would be wrong and unfair to inventors to find an invention obvious in hindsight and particularly if it was only arrived at after a series of steps which involve the cumulative application of that hindsight. In some cases success at each step is a necessary predicate for the next one and it is only the knowledge of the invention as the target which could motivate a skilled person to take each step without knowledge about the next one. That is not this case.

All that a skilled team is doing in carrying out the exercise above is putting into effect what is taught expressly by Brassington in an obvious way. The various choices (choosing a plastic film which is in fact impervious, choosing a silicone rubber for the non-tacky silicone) are not tainted with hindsight, they are soundly based on Brassington and the common general knowledge. The choices of materials are choices which present themselves when the skilled person reads the document. In effect the choices operate in parallel whereas the impermissible steps of Technograph form a series.

The one aspect of the matter which follows from the earlier choices is the “step” of making the wound dressing. But a skilled team would be well motivated to make one and would have every expectation that it could be done. No doubt coating an apertured plastics film is a potentially ticklish exercise but in my judgment letting the silicone cure first and then cutting the perforations afterwards is obvious. Claim 6 lacks inventive step.

If claim 6 is obvious so is claim 7. Using soft plastic films in wound dressings was part of the common general knowledge. It is not a further step over claim 6 because the skilled person has to select a plastics film to make the wound dressing. Two obvious plastic films to use were films like the ones in the OPSITE and Melolin products which were relatively soft plastic films on any view.

The point of claim 10 is to use a composite material including a plastic layer and a fibre layer. The point is to improve adherence between the silicone gel and the carrier by increasing the contact surface area between the silicone and the film. Dr Meirowitz’s view was that if adherence was a problem there were a number of options which would immediately be considered. They were changing the silicone or film; using a silicone primer or increasing the contact surface area either by roughening the surface or applying the silicone to a fibrous or highly porous structure and then laminating it to the surface of the film. Mr Fabo was not sure that increasing the surface area would be obvious but he agreed it would be on the list of things to test. I did not have my attention drawn to anything said by Prof Clarson on this topic.

Mölnlycke submitted that Brightwake’s case on this point was also an impermissible step by step approach. I do not agree. The point of claim 10 is to achieve good adherence. Adherence between the silicone and the plastic film is something which will be considered by the skilled team. It is not a step beyond the exercise of applying silicone to the film. If the skilled team wants good adherence between the silicone and the plastic film they are coating, then it is the role of the silicone specialist to address that issue. All of Dr Meirowitz’s options are obvious ways of doing it. If claim 6 is obvious so to is claim 10.

Much of the argument and evidence on obviousness at trial related to whether it was obvious to coat only one side of the plastics film with silicone. Clearly if it is obvious to coat silicone gel on the wound contacting side with no silicone of any kind on the other side, then claim 6 is invalid regardless of the gel/elastomer/rubber point.

The strongest evidence in support of the obviousness of coating on only one side was the following. Mr Fabo explained the benefits of coating only one side as being (a) making the dressing easier to handle, because the dressing is less likely to stick to itself or the user’s gloves, (b) avoiding the dressing sticking to clothes and bedding once in place, and (c) cost (silicone gel is expensive). He accepted in cross-examination that it would be obvious to the skilled person in 1992 that if he put tacky silicone gel on both sides of the dressing then these matters would arise. I understood him to mean that he accepted that the drawbacks which are the converse of these benefits would be obvious if tacky gel was placed on both sides.

However Mr Fabo did not think it was obvious to coat on only one side for the very simple reason that he thought Brassington tells the reader to coat both sides.

Brightwake also submitted that the advantages of tacky silicone which Mr Fabo agreed would be apparent from his own patent would also be apparent from Brassington. Although the documents are different documents and one has to be careful with a submission of that kind, in this case I agree that in terms of the advantages of using tacky silicone gel on the wound contacting side of a wound dressing the teaching of Brassington is just as positive as the teaching of the patent in suit. In this case the fact it is obvious from the patent to use silicone in dressings other than the dressings precisely disclosed is some faint evidence that it is also obvious to use silicone in dressings other than the dressings precisely disclosed in Brassington.

Prof White’s opinion was that applying silicone to only one side was obvious. His view expressed in his report was that there was no obvious clinical reason for a skilled person to coat with silicone on both sides although that was qualified in cross-examination (see below). He thought the skilled person would appreciate that what was important was the character of the wound contacting surface. He noted that Brassington refers specifically to having silicone on the skin-contacting surface in its first paragraph. He thought the skilled person would understand that the non-tacky silicone used on the non-wound contacting surface in examples 2 and 3, may reduce adherence to clothing or bed linen but the skilled person would not consider this necessary.

Mölnlycke submitted that Prof White’s views about this aspect of Brassington were based on an erroneous construction of the word “coating” on the basis that he thought Brassington differentiated between coating and encapsulation. Prof White accepted that he was wrong about this and that this part of his report needed revision. I agree.

Dr Meirowitz also gave evidence about the obviousness of coating with only one side but in my judgment the silicone specialist’s role in the skilled team would not be to make a decision of that kind. The impetus for deciding what sort of wound dressing to make comes from team members skilled in the art of wound dressings exemplified by Mr Fabo or Prof White. The silicone specialist’s role would be to address silicones and how to employ them once a decision to work with silicone was already being actively considered.

Starting from Brassington and taking the step of coating with silicone on only one side is the kind of step which looks obvious in retrospect. However in my judgment it was not obvious, viewed without hindsight. It is not contemplated in the document itself and does not form part of the common general knowledge. The silicone coated wound dressing in the common general knowledge in 1992 (Silicone N-A) was coated on both sides. Coating on one side only is a simple step to take but that is entirely different from saying it was an obvious step to take.

I should end this topic by recording that I do not regard the evidence about the handling and sticking advantages of coating on only one side as helpful to Mölnlycke’s case. Mr Fabo’s report gives handling and avoiding sticking to bedding and clothing as advantages of his invention. Prof White was cross-examined and accepted that reducing adherence to bedding and clothing was a perfectly good clinical reason for coating with both sides and therefore was a feature of the prior art. The point of course was that Mr Fabo was talking about the advantage of silicone gel being on one side and was clearly working on the basis that silicone gel is tacky. Whereas the answer elicited in cross-examination from Prof White was about the purpose of putting “non-tacky gel” on the upper side of the dressing. It is entirely obvious to put the tacky silicone gel only on the wound contacting side. Brassington tells the reader to do just that and the advantage obtained is the same as the one in the patent. That is why Brassington puts the non-tacky silicone on the upper surface.

I can deal with the Fabo prior art very briefly. In effect the document corresponds to example 1 of Brassington. Fabo discloses a wound dressing which employs silicone gel. The dressing is a knitted network encapsulated by the gel. Unlike Brassington there is no reference to making a dressing by coating a plastic film with gel. Unlike Brassington there is no reference to putting non-tacky silicone on the outside and tacky gel on the wound contact side. For what it is worth Fabo goes somewhat further than Brassington in explaining the benefits of silicone gel in a wound dressing but that makes no difference.

Claim 6 is not obvious over the Fabo prior art. The tacky/non tacky approach I have addressed over Brassington does not arise over the Fabo prior art. If coating only one side with silicone is not obvious over Brassington, it is not obvious over this Fabo prior art.

None of the Episil or Episil Absorbent products infringe claims 6, 7 or 10 of the patent.

The claims include within their scope a wound dressing comprising an apertured plastics film with silicone gel only on the wound contacting side and non-tacky silicone elastomer (not gel) on the other side. Such a wound dressing is obvious over Brassington. Claims 6 to 10 are invalid.