Stretchline Intellectual Properties Ltd v H & M Hennes & Mauritz UK Ltd

The Claimant ("Stretchline") is the owner of UK Patent GB 2 309 038 ("the Patent"). The Patent was filed on 18 April 1996 and is entitled "Tubular fabric and method of making the same". The Patent is concerned, in particular, with tubular fabric in underwired garments such as brassieres.

In 2010 Stretchline brought a claim for infringement of the Patent against the defendant (“H&M”), alleging certain brassieres sold by H&M fell within the claims of the Patent. H&M denied infringement of the Patent and counterclaimed for revocation. Those proceedings, including the counterclaim, were settled following a mediation and an agreement dated 3 October 2011 was entered into between Stretchline and (amongst others) H&M ("the Settlement Agreement").

On the 28 March 2013 Stretchline commenced these proceedings, alleging that H&M was again selling brassieres that fell within the claims of the Patent. Initially, Stretchline alleged breach of contract and infringement of patent. H&M asserted in its defence that the garments did not fall within any claims the Patent and also claimed in its defence and counterclaim that the Patent was invalid.

In October 2014, H&M's invalidity defence and counterclaim were struck out by Sales J (as he then was) on the basis that the Settlement Agreement precluded H&M from raising the issue of invalidity in these proceedings. This decision was affirmed on appeal; Stretchline Intellectual Properties Ltd v H&M Hennes & Mauritz [2015] EWCA Civ 516. Following the Court of Appeal judgment Stretchline discontinued its claim for infringement and only pursues its claim for breach of the Settlement Agreement.

The Settlement Agreement contains the following recitals:

“A.

Proceedings have been commenced by the Claimant against the Defendants by way of High Court Claim No. HC10C00278 filed on 30 July 2010 in the High Court of Justice (the “UK Proceedings”) arising out of the Claimant's claim for infringement of United Kingdom Patent Number GB 2,309,038 (the “UK Patent”) by the UK Defendant (the “UK Dispute”) and US Civil Action no. 2:10-CV-371 (EDVA) filed on July 20 2010 in The United States District Court for the Eastern District of Virginia (the “US Proceedings”) again arising out of the Claimant's claim for infringement of U.S. Patent Number 6,071,578 (the “US Patent”) by the US Defendant (the “US Dispute”). In both the UK and US dispute the Defendants have denied all claims and liability.

B.

Following mediation between the Parties on 31 May 2011, pursuant to a Mediation Agreement dated the same date, the Parties agree to compromise the UK and US Proceedings on the terms set out in this Settlement Agreement.

C.

The Parties intend that this Agreement bring finality to this dispute worldwide with respect to the claims asserted or those that could have been asserted with regard to the products at issue.”

Clause 1 of the Settlement Agreement includes the following definitions:

“1.1

“Claims” shall mean any claim made in either the UK Proceedings or the US Proceedings (including any claim for damages, interest and costs) and any other potential claims in relation to the subject matter of those proceedings elsewhere in the World.

1.2

“H&M Low Volume Fabric” shall mean any wire casing product with a volume of fusible yarn of approximately 0.3–0.7% of the total volume of yarn in any tubular fabric component, including but not limited to the samples provided the Defendant to the Claimant under cover of a letter of 16 May 2011 from Shoosmiths Solicitors to the Claimant c/o Potter Clarkson.

1.3

“Accused Product” shall mean:

1.3.1

any product which falls within any of the claims of any of the Patents;

but does not include the H&M Low Volume Fabric.

1.4

“Patents” shall mean:

1.4.1

United Kingdom Patent Number GB 2,309,038;

…

1.6

“Prohibited Acts” shall mean:

Making, disposing of, offering to dispose of, using, importing or keeping (whether for disposal or otherwise) in any of the Prohibited Jurisdictions any Accused Product; during the duration of the terms of the Patents in their respective jurisdictions so long as each Patent remains enforceable in that jurisdiction;

1.7

“Prohibited Jurisdictions” shall mean the United Kingdom, the United States of America, Germany, France, Belgium, and/or Italy.

1.8

“Sell-Through Period” shall mean the period from the date of this agreement until 31 December 2011.

…

1.13

“UK Proceedings” has the meaning set out in paragraph A of the Background to this Settlement Agreement.”

Clause 3 of the Settlement Agreement provides, amongst other things, that:

“3.1

In consideration of the Claimant agreeing to compromise the Claims against the UK Defendant and the US Defendant (together the “Defendants”) the Defendants each agree:”

3.1.1

between them to pay, by way of costs, to the Claimant the sum of £235,000 (the “Settlement Sum”) in full and final settlement worldwide of all Claims present and future made by the Claimant and/or its subsidiaries/associate companies;

3.1.2

not now, or at any time in the future to do, or procure or authorise the commission by any third party to do any of the Prohibited Acts, nor collude with any company within the same group of companies in relation to the commission of any of the Prohibited Acts, whether by their directors, officers, servants or agents or any of them or otherwise whatsoever.

3.1.3

to ensure that by the date of the expiry of the Sell-Through Period no H&M retail stores in the United Kingdom, the United States of America, Belgium, Germany, France and Italy will at that time or in the future dispose or, offer to dispose of, use, or keep (whether for disposal or otherwise) any Accused Product.

…

3.3

If after the sell-through period has expired, the Claimant does discover a product in an H&M Store within the territory referred to in 3.1.3 above which it believes to be a violation of this Agreement, the Claimant will promptly bring such product to the attention of the UK and US Defendants who shall promptly investigate matters and thereafter the Parties hereto shall, without prejudice to the Claimant's rights as set out in this Agreement or generally, work together to resolve the situation to each other's satisfaction.”

So, in summary, H&M agreed not to deal in any product which fell within any of the claims of the Patent and paid an agreed sum by way of costs to Stretchline. It was allowed a sell-through period and was entitled to continue to sell “H&M Low Volume Fabric”, which meant any wire casing product with a volume of fusible yarn of approximately 0.3–0.7%. On this basis, the parties settled their differences and entered into the Settlement Agreement.

The Patent is concerned, in particular, with tubular fabric used to encase underwires in garments such as brassieres. The Description states that there was a known problem with such fabric tubing at the priority date (page 1 lines 12-19):

“A considerable problem with known fabric tubing for underwires is that the ends of the underwires can penetrate the tubing, either during the course of garment manufacture or in use by a wearer.

At present, a significant proportion of brassiere (bra) manufacturers (sic) products are returned because of protrusion of the underwire through the fabric tubing.”

The Patent proposes to solve this problem by inclusion of a fusible yarn which, on melting, strengthens the tubular fabric.

Claim 1 of the Patent is a process claim which provides for:

“a method for making a tubular fabric comprising providing a support yarn and an elastomeric yarn; characterised in that a fusible yarn is also provided and in that the yarns are formed into a tubular fabric whereby the fusible yarn is arranged within the fabric tube so that it is capable of forming a penetration barrier.”

The dispute between the parties concerns the correct interpretation of the final words of the claim and in particular whether the garments allegedly sold in breach of the Settlement Agreement contain “a penetration barrier”.

In summary, Stretchline contends that a penetration barrier is created by incorporating (in particular by weaving) a fusible yarn into the tubular fabric and heating it. A fusible yarn acts, in effect, as an adhesive. When heated during the fabric dyeing process, the adhesive melts and the fusible yarn ceases to exist. The adhesive spreads itself over the surrounding fibres in the fabric to form points of adhesion or bonding between those fibres. Stretchline submits that this is what is meant by “a penetration barrier”. The Patent is claiming a structure that, by reason of bonding of the fibres, is better able to resist penetration (for example by wire) than would be the case if the fusible yarn had not been used.

H&M contends that the Patent requires that the fusible yarn must an identifiable, layer-like barrier or lining. On this basis, points of adhesion are not sufficient. H&M argues that the Patent describes and claims fusible yarn which, on melting, forms a substantially continuous liner which provides the required penetration barrier. It denies that it is possible to equate increased resistance to penetration with the presence of a barrier.

H&M also argues that, on Stretchline’s interpretation, the Patent would be clearly invalid in the light of common general knowledge at the priority date. It submits that a skilled reader, aware of the common general knowledge, would reject an interpretation so broad that it would clearly lead to invalidity. He/she (hereafter “he”) would realise that this would be a foolish result, which could not have been intended by the draftsman of the Patent.

The starting point is, of course, the decision of the House of Lords in Kirin-Amgen Inc and Others v Hoescht Marion Roussel and Others [2005] RPC 9, and in particular the exposition by Lord Hoffman of the correct approach to claim construction under the Protocol to Article 69 of the European Patent Convention. As he stated at [34]:

““Purposive construction” does not mean that one is extending or going beyond the definition of the technical matter for which the Patentee seeks protection in the claims. The question is always what the person skilled in the art would have understood the Patentee to be using the language of the claim to mean. ”

The Protocol rejected what was regarded as the “literalist” approach, whereby the description and drawings were only referred to in order to resolve an ambiguity in the language of the claims. It also rejected a broad approach, where the claims were treated merely as a guideline. In the context of the present case, it is important to bear in mind Lord Hoffman’s explanation of why the literalist approach was rejected at [29] – [30]:

“These rules, if remorselessly applied, meant that unless the court could find some ambiguity in the language, it might be obliged to construe the document in a sense which a reasonable reader, aware of its context and background, would not have thought the author intended. Such a rule, adopted in the interests of certainty at an early stage in the development of English law, was capable of causing considerable injustice and occasionally did so. The fact that it did not do so more often was because judges were generally astute to find the necessary “ambiguity” which enabled them to interpret the document in its proper context. Indeed, the attempt to treat the words of the claim as having meanings “in themselves” and without regard to the context in which or the purpose for which they were used was always a highly artificial exercise.

It seems to me clear that the Protocol, with its reference to “resolving an ambiguity”, was intended to reject these artificial English rules for the construction of patent claims. As it happens, though, by the time the Protocol was signed, the English courts had already begun to abandon them, not only for patent claims, but for commercial documents generally. The speeches of Lord Wilberforce in Prenn v Simmonds [1971] 1 WLR 1381 and Reardon Smith Line Ltd. v Yngvar Hansen-Tangen [1976] 1 WLR 989 are milestones along this road. It came to be recognised that the author of a document such as a contract or patent specification is using language to make a communication for a practical purpose and that a rule of construction which gives his language a meaning different from the way it would have been understood by the people to whom it was actually addressed is liable to defeat his intentions.”

Relevant principles of patent constructions were summarised by the Court of Appeal in the subsequent case of Virgin Atlantic Airways v Premium Aircraft Interiors UK [2010] R.P.C. 8 at [5]. It is unnecessary for me to set out those principles in this Judgment, but I shall have regard to them when deciding the issue of interpretation raised by this case.

Mr. Burkill QC, who appeared on behalf of H&M, submitted that a construction of the claim which reads onto the prior art acknowledged in the Patent, or onto the common general knowledge, is to be avoided unless the specification unequivocally requires it. He referred to the well-known explanation of Jacob J in Beloit v Valmet (No. 2) [1995] RPC 255 at 270:

“I believe Article 69 of the EPC does not legitimately allow courts to construe claims using the prior art either to widen them or narrow them. There is normally no reason to suppose the Patentee when he set the limits of his monopoly knew of a particular piece of prior art which is therefore irrelevant in deciding what those limits are. Of course the position is different if the prior art is specifically acknowledged in the Patent. The purposive construction would lead to a construction of a claim which did not cover that acknowledged prior art: it can hardly have been the inventor’s purpose to cover that which he expressly recognises was old.”

Mr Burkill referred to Terrell para 9-107, which, after citing the above passage, explains as follows:

“The overall principle is therefore that a construction which leads to a foolish result should, if possible, be rejected as being without the intention of the patentee, for a construction which does not lead to an absurd result is to be preferred. However a finding of invalidity cannot of itself be regarded as an absurd result, unless the relevant piece of prior art is specifically acknowledged and sought to be distinguished in the Patent, or unless the invention would to the knowledge of the ordinary reader then be obvious simply in the light of the common general knowledge””

Mr Burkill pointed out that this is no more than the application of the well known principle that:

“…if possible, a specification should be construed to as not to lead to a foolish result or one which the Patentee could not have contemplated”

(per Lord Russell in Electric & Musical Industries v. Lissen (1936) 56 RPC 23 at 39).

Mr Caddick QC, who appeared on behalf of Stretchline, noted that the principle that the court should eschew a construction that would lead to a finding of obviousness over common general knowledge has been expressly considered by the Court of Appeal in Adaptive Spectrum v British Telecommunications [2014] EWCA Civ 1462. Having referred to Beloit v Valmet, and to the passage from Terrell which I have set out above, Floyd LJ said at [111]:

“As with any canon of construction, one must be wary of treating it as a rigid rule. Moreover as soon as one departs from documents specifically acknowledged in the specification, the skilled reader has no basis for assuming that the patentee was aware of the document in question. Still further, where the objection is one of obviousness rather than lack of novelty, a value judgment is involved on which widely differing views are possible. It is true that if the document is said to form part of the common general knowledge, it might be said to be more likely that the patentee is aware of it. But a patentee may have been isolated from the common general knowledge, or may, despite the later finding of obviousness, have genuinely believed that he had made an invention over it.”

There is no real dispute about the person to whom the Patent is addressed. He would have undergone technical education and training in the field of textile technology, and would have an understanding of how to incorporate different yarns into a woven structure. He would have knowledge and experience of the techniques of textile manufacture and weaving, and weaving in the context of narrow fabrics. He would also have a knowledge and understanding of the chemical properties and behaviour of co-polymers and how, when incorporated in fibre form into the structures of a woven fabric, a polymer would behave when heated.

Following cross-examination, both sides attacked the witnesses called by the opposite party. I will deal with this fairly briefly, as I do not accept these criticisms. Prof. Roshan Shishoo gave expert evidence on behalf of Stretchline. He worked as Professor in Fibre Technology at Chalmers University of Technology from 1990 to 2002 and in 1992 was appointed Director of Research and subsequently Managing Director of the Swedish Institute for Fibre and Polymer Research, a post that he held until February 2003. It was alleged on behalf of H&M that he was an academic with little industry experience, that his appreciation of the common general knowledge was incomplete, and that his answers were rambling and off-point. I reject these submissions. English was not Prof. Shishoo’s first language, and at points he struggled to convey his exact meaning. However, he overcame this difficulty and I consider that he was an excellent teacher in the relevant field, and a very good expert witness.

Mr Robert Glenn is one of the named inventors of the Patent who gave evidence of fact on behalf of Stretchline. It was alleged that he was a thoroughly unsatisfactory witness in that he concealed the truth about his role as head of IP for Stretchline, although the motivation for such concealment was not explained. Mr Glenn gave evidence about some tests that had been done on behalf of Stretchline before commencement of these proceedings in order to see which, if any, of the brassieres purchased from H&M contained more than the maximum limit of 0.7% for H&M Low Volume Fabric. Initially, it was alleged that these tests did not take place and the results were a fabrication. However, this allegation was not pursued by the end of the trial. Instead, it was alleged that Mr Glenn’s evidence about these initial tests was inconsistent with that of another witness of fact called on behalf of Stretchline, a Mr Weerawansa. I do not accept these criticisms. Whilst it was unclear what had become of certain of the documents which evidenced the initial tests, these tests were, at best, of peripheral relevance. They were not the subject of a Notice of Experiments and so could not be relied on by Stretchline in these proceedings. Furthermore, it was common ground that the fusible material in all of the garments the subject of this claim exceeded the maximum limit for H&M Low Volume Fabric. I consider that Mr Glenn was an honest witness with very considerable experience in the industry, who was doing his best to assist the court.

Prof. Julian Ellis gave expert evidence on behalf of H&M. He is a Chartered Textile Technologist working as a consultant in areas of textile manufacture, with a particular interest in the field of stitching and fabric forming technologies. Before becoming a consultant in 1984 he worked for W Ribbons Ltd where he was Research and Development Manager working with narrow fabrics (which are textiles that are no more than 300mm in width). He was criticised on behalf of Stretchline on the basis that he had verified the PPD and SPPD even though he knew that they were incomplete. This is a fair point, and I consider that Prof. Ellis did not appreciate the importance of the PPDs, as distinct from his expert reports. This is unfortunate, but, as discussed in more detail below, I do not think that it is appropriate to criticise Prof. Ellis personally for this. Overall, I thought that he gave fair answers during cross-examination, and was trying to assist the court. He agreed with more of Prof. Shishoo’s evidence than was apparent from his written reports.

The expert reports include various topics which may have been common general knowledge at the priority date, but which are unnecessary for me to consider when resolving the issue of construction raised by this case. I will discuss relevant aspects of common general knowledge (a) when analysing the disclosure of the Patent and (b) when considering H&M's submission as to obviousness in the light of common general knowledge, if Stretchline’s construction is accepted.

There are two aspects of common general knowledge that are of particular importance when considering the disclosure of the Patent.

First, fusible yarns were well-known for many years before the filing date. Prof. Ellis explained that fusible yarn was also known as “binding yarn”, “bonding yarn” and “barrier yarn”. These names are descriptive of its purpose. Its normal function is, on melting and cooling, to bond fibres together within a fabric in order, for example, to strengthen the material. It was known to act as an adhesive, for example, at points of contact between weft and warp. Prof. Ellis explained this at [27] of his first Report:

“The degree to which the addition of fusible fibres makes a difference to its performance depends on the density of fusible fibres used. If a small amount of fusible yarn is used it will only attach itself to the neighbouring yarns, whether these are in the adjoining weft or warp, where they touch or closely overlap. The points of adhesion of fairly random but mean that the yarns are overall more tightly bonded together. Typically this would prevent the unraveling of the fabric.”

Second, Prof. Shishoo explained that the skilled person would have known in 1996 that it was impossible to form a continuous, discrete layer or liner from fusible yarn in a tubular fabric, particularly in the case of woven fabric as described and shown in Figure 1 of the Patent. He referred to “Grilon”, a preferred fusible yarn referred to in the Patent, and explained that molten Grilon has a high viscosity. He stated at [26] of his second report:

“A high viscosity is needed because a lower viscosity would mean that the molten polymer would simply leak out of the fabric structure. This would be particularly problematic for a tubular fabric; instead of fusing the yarns of fabric together the polymer would cause the inner surfaces of the tube to stick together defeating the object of having a tubular fabric. Therefore a high viscosity is required. However, with a polymer of higher viscosity, the woven structure of the fabric will impede the polymer flow to the extent that it simply would not form a continuous layer of the polymer. In fact, I do not think it would be possible to include enough fusible yarn within the fabric to create a continuous layer and certainly not if one uses the preferred quantities of fusing yarn referred to in the Patent (namely 5% to15%). Indeed it would make no commercial sense to try. In my opinion these facts would have been apparent to the skilled reader.”

Prof. Ellis estimated that 50% of fusible yarn within the fabric would be required to form a discrete layer or liner, because the fusible yarn was too viscous to spread widely and its flow would be impeded by the main yarns in the fabric structure. He accepted during cross-examination that he would not expect the fusible material to form a full layer (T3/434/14-436/10).

There is very little dispute on this issue between the experts, but insofar as there is a difference of opinion, I accept the view of Prof. Shishoo. There was no suggestion that Prof. Ellis had actually tried to form a discrete layer in woven fabric using any particular proportion of fusible yarn. I find that skilled person would have known at the priority date that it would not be practical to form a discrete layer from fusible yarn in a woven fabric. Prof. Ellis thought that fusible yarn was about 10 times as expensive as the other yarns used in the invention. Because of the additional cost of such material, it would not make commercial sense to try to form a layer of such material, given that simply including a small quantity as adhesive within the structure would increase the resistance to penetration, and there was no reason to believe that a discrete layer would be any better.

I have referred above to the problem addressed by Patent. The description explains at page 1 lines 20-26 that:

“Underwire protrusion through the tubing is perhaps most commonly the result of washing the garment such as a bra in a washing machine. Whilst such washing is not presently recommended by garment manufacturers, it is commonplace. Clearly, product failure as a result of underwire protrusion is costly and can have a deterious (sic) effect on customer satisfaction. The present invention seeks to avoid these and other problems of the prior art.”

It follows that the object of the invention is to render the tubular fabric more resistant to penetration, in order to solve the problem of, for example, underwire protusion. After the consistory clause, the description states that fusible yarn is a very important feature of the invention.

Page 2 lines 6 to 11 states that:

“By “fusible yarn” we include the meaning that the yarn can be melted at a predetermined temperature and cooled to adhere to the support yarn. Advantageously, the fusible yarn melts at less than 100°C, especially 90°C or less, and can be cooled to produce a material having a higher melting point than the predetermined temperature and preferably more than 100°C.”

That passage contemplates that, on melting and cooling, the fusible yarn will “adhere to the support yarn”. In my judgment this is describing the normal function of fusible yarn as an adhesive, which sticks to fibres in the fabric on melting and cooling, and this is how the skilled person would understand the description from his common general knowledge.

The description identifies a polyamide yarn sold by EMS-CHEMIE AG under the Trade Mark GRILON as the most preferred fusible yarn for use in the invention. I have accepted the evidence of Prof. Shishoo that the skilled person would know that Grilon was too viscous to form a discrete layer on melting and cooling, particularly in woven fabric.

The description continues at pages 2 line 38 page 3 line 1:

“Preferably, the fusible yarn is treated by heating whereby it melts and spreads over the interior surface of the tubular fabric. On cooling, the fusible yarn adheres to the other yarns of the fabric to produce a tubular fabric have a durable inner lining of the melted fusible yarn.”

It is clear from this passage that the fusible yarn is not intended to form a barrier which is discrete from the rest of the yarns of the fabric. On the contrary, the disclosure is that the fusible yarn will adhere to the other yarns in the fabric on melting, thereby rendering the tubular fabric as a whole more durable. The reference to “durable inner lining” is to the composite of yarns with points of adhesion following melting and cooling of the fusible yarn. Prof. Ellis considered that “the use of fusible yarn in order to bond fibres together to improve fabric durability” was common general knowledge at the priority date (Ellis 1 [32]). The Patent is describing a particular application of fusible yarn, to improve the penetration resistance of tubular fabric.

This disclosure is reinforced at page 3 lines 19-25, which states that the fusible yarn of the invention is intended to include:

“any yarn which can melt at a predetermined temperature, preferably 75 to 90° C, and adhere to other yarns of the fabric to form a penetration barrier.”

Accordingly, it is the composite of fused yarn, together with the other yarns of the fabric which forms the penetration barrier. The fusible yarn is not expected to achieve this on its own.

Page 5 lines 6-11 explains that it is preferred that the yarns are formed into a tubular fabric by a weaving process. I have found that the skilled person would know that it was not practical to form a discrete layer from fusible yarn in woven fabric.

Page 6 line 28- page 7 line 3 states that:

“in the finished fabric weight the percentages of the different yarns are preferably in the ranges:-

(i)

fusible yarn 5-15%, especially approximately 8%

(ii)

Elastomeric yarn 0.5-10%, especially 1-2%

(iii)

catch thread less than 1%

(iv)

support yarn – balance to give 100%”

I have referred to the evidence of Prof. Ellis that it would not be possible to form a layer from fusible yarn unless about 50% of such yarn was included in the fabric, and according to the evidence of Prof. Shishoo that this would not be possible at all with woven fabric. On the evidence of both experts, if H&M's interpretation was correct, the preferred weight ranges would be impractical and it would not be possible to make this preferred embodiment. The skilled person would know this from his common general knowledge, and this is a clear indication that H&M’s interpretation is incorrect.

Page 7 lines 5 et seq. refers to spreading of the fusible yarn on melting. This is consistent with either interpretation, as, on melting, the fusible yarn will inevitably spread. The description continues at page 7 lines 9 -13:

“Preferably, the method of the invention comprises a further step of treating the tubular fabric by heating to melt the fusible yarn so that it spreads over the tubular fabric and is capable of forming a penetration barrier. On cooling, the melting yarn adheres to the other yarns of the fabric to form a durable inner tube liner.”

This passage is relied on by both parties. On the one hand, it is capable of meaning that the penetration barrier must be formed from the fusible yarn on its own. On the other hand, it is capable of meaning that the penetration barrier is formed by adherence of the melted yarn to other yarns in the fabric, the effect of which is to strengthen the fabric tube. Having regard to the common general knowledge, and to the entire disclosure of the Patent, in my judgment the latter interpretation is correct.

Page 8 line 6 to 9 states that:

“The fabric tubing produced in accordance with the invention has a durable inner lining of fusible yarn which is extremely resistant to penetration by underwires.”

This is similar to a passage at page 12 lines 10-13, which refers to “a durable inner lining of fused polyamide on the interior surface of the fabric tubing”. Read literally, these passages indicate that the fused yarn, on its own, must form a durable inner liner. Read in context, and with the benefit of common general knowledge, they are referring to the increased resistance to penetration of the fabric tubing as a result of adherence of the melted yarn to other yarns of the fabric.

Page 8 lines 10 -17 refer to the advantageous resistance to penetration of the fabric tubing of the invention, as compared to known fabric tube. This is a property of the fabric tubing as a whole, rather than a particular layer within it.

Figure 1 of the invention shows a fabric tape produced in accordance with a preferred weaving method of the invention. For the reasons explained above, if H&M is correct in its construction, it would not be practical to produce this preferred embodiment.

Page 14 lines 9 to page 15 line 8 disclose the results of tests on an “L + M Sewability Tester with a 90’s medium ball needle to represent an underwire”. H&M submitted that this test is more appropriate for detection of an identifiable layer within the fabric, rather than for detection of increased resistance to penetration. However, it appears from the evidence that this was the only available method at the priority date for testing increased resistance to penetration. In any event, the Patent explains that the purpose of the tests is to “demonstrate the increased resistance to penetration afforded by the tubular fabric of the invention compared to known fabric tube for receiving underwires”; (page 14 lines 9-11). It is of significance that it is the tubular fabric of the invention, as opposed to a discrete part of it, which achieves increased resistance to penetration.

Claim 1 of the Patent may now be read in the light of the description and drawings, and having regard to common general knowledge:

“a method for making a tubular fabric comprising providing a support yarn and an elastomeric yarn; characterised in that a fusible yarn is also provided and in that the yarns are formed into a tubular fabric whereby the fusible yarn is arranged within the fabric tube so that it is capable of forming a penetration barrier.”

As a matter of grammar, the pronoun “it” would naturally be read as referring to the fusible yarn. This is consistent with independent claim 19, which is a product claim:

“A tubular fabric comprising a support yarn and an elastomeric yarn; and characterised in that a fusible yarn is arranged so that it is capable of forming a penetration barrier within the fabric tube, and in that it is obtainable by the method of anyone of claims 1 to 16.”

There are several references in the description to an “inner lining”. H&M submits that these are all consistent with the language of the claims, which requires that the fusible yarn is capable of forming, and forms, the penetration barrier as a discrete layer.

However, as the passage which I have cited from Kirin-Amgen makes clear, the question is what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. I bear in mind that the patentee is using language to make a communication for a practical purpose and that an interpretation which gives his language a meaning different from the way it would have been understood by the people to whom it was actually addressed is liable to defeat his intentions.

Mr Caddick submits, and I accept, that fusible (bonding) yarn functions to fuse other yarns and filaments together. It does not function as a covering or as a layer. On melting and cooling it fuses the remaining (non-fusible) fibres and yarns together, like mortar bonds the bricks of a brick wall. Like mortar, it is this fusing that gives strength to the structure. No-one would think of creating a barrier of just mortar and by itself it would provide little strength. That is not its function. Its function is to bond other materials. The skilled person would appreciate that this is the function of the fusible yarn in the invention when reading the Patent.

Following cross-examination, I consider that Stretchline’s interpretation is supported by the evidence of both experts. Prof. Shishoo repeatedly explained that no skilled person would consider that the Patent was referring to a discrete layer of fused material. Mr Burkill submitted that Prof. Ellis’s evidence suggested that if Stretchline was correct, experiments would be required in order to construe the claim, which would fail to provide reasonable certainty for the public. He referred to Prof. Ellis’s cross-examination at T3/435-6:

Q. Therefore a high viscosity is required ... (reads to the words) ... In my opinion these facts would have been apparent to the skilled addressee." I am assuming you would disagree with the end of that, would you?

A. I would have tried it to see what happened. I would have done it by experiment.

Q. Given that fusible yarn has a high viscosity, and is very unlikely to form a continuous layer, does that not indicate to the skilled addressee that that is not what this patent is trying to achieve?

A. That is not what it says.

Q. Does the patent talk about ----

A. We are coming back to the construction of the patent as opposed to the wording.

Q. Yes.

A. No, I would not expect it to make a full layer, but that is not what the patent says.

Q. So, you would say that a skilled addressee, even though he knows that fusing yarn has a high viscosity, it is very unlikely to form a continuous layer. You say he is nevertheless going to read this as what the patentee means by it?

A. I would have expected the patentee -- when I read this patent the very first time, I would have expected it at first consideration to form a layer.

Q. Even though you know that is not how fusing yarn works?

A. When working on this later, I would have realised there is not enough to form a continuous layer.

I understood Prof. Ellis to say that on reading the Patent for the very first time he gained the impression that it required such a discrete layer formed from fusible yarn. However, on further consideration, he realised that there was not enough fusible yarn to form such a layer. Again, this indicates that H&M’s construction is incorrect.

I have reached the conclusion that the skilled person would understand that it is the fabric tube that must resist penetration and the fusible yarn is only effective when it bonds with other yarns to increase the tensile strength of the fabric tube. The claims require that the fusible yarn is (or is capable of being) the cause, or trigger, for formation of the penetration barrier, which comprises the remaining yarns as a composite structure. The claims do not require the fusible yarn to form a discrete, continuous layer, which the skilled person would know was impractical. Furthermore, it is clear from the description, and from common general knowledge, that an absolute barrier to penetration is not required. Fusible yarn is used to achieve a higher resistance to penetration than would be the case in conventional tubular fabric, in order to address the problem of underwire protrusion.

Furthermore, the claims use general language to define the invention. The specification refers to a fabric made in accordance with the invention being “two or three times more resistant to penetration”. That may well be true of the preferred embodiment, but it is not a limitation which is contained within the claims. The claims require a material increase of resistance to penetration, having regard to the problem that the Patent addresses, but do not set a minimum limit for resistance. Nor do they include the L+M sewability test as a feature of any claim. In this regard Floyd J (as he then was) stated in Nokia v Ipcom [2009] EWHC 3482 at [41] that:

“Where a patentee has used general language in a claim, but has described the invention by reference to a specific embodiment, it is not normally legitimate to write limitations into the claim corresponding to details of the specific embodiment, if the patentee has chosen not to do so.”

H&M contends that, on Stretchline’s construction, the skilled person would appreciate that the invention would be invalid in the light of common general knowledge, as bonding yarn would be used for its well-known purpose of bonding. This, it is contended, would be a foolish reading, and should be rejected.

I do not accept this argument for the following reasons. First, I have referred to the judgment of the Court of Appeal in this case that that the Settlement Agreement precluded H&M from raising the issue of invalidity. It is clear from the judgment of Kitchin LJ at [25] - [34], [46] and [52] that H&M is precluded from raising, in its defence, a squeeze between non-infringement and invalidity. As the argument developed, and attractively as it was put by Mr. Burkill, it appeared to me that this was another attempt to introduce a squeeze between non-infringement and invalidity, rather than an issue of real relevance to construction.

Second, I have reached a clear view as the correct interpretation of the claims of the Patent. Had validity been in issue, and had this interpretation led to a finding of invalidity, I would still been of the same view. The consequence would have been, on this hypothesis, that the Patent would have been invalid for lack of inventive step; in this respect see Adaptive Spectrum (supra). However, this argument was not open to H&M.

Third, I have reached the conclusion that even if the argument had been open to H&M, the alleged squeeze between non-infringement and obviousness on the basis of common general knowledge would have failed on the evidence.

H&M relied on the following in support of its common general knowledge attack:

The law in relation to common general knowledge was reviewed by Arnold J in KCI Licensing v Smith & Nephew [2010] FSR 31 at [105] - [115] and this was approved by the Court of Appeal at [2011] FSR 8 at [6].

In relation to the Tortora book, this was a US academic publication and Prof. Shishoo explained that, despite his extensive academic background and frequent visits to US universities, he never heard of it. Prof. Ellis was unaware of this publication at the priority date and only purchased it about four years ago. I am not satisfied that its contents were common general knowledge at the priority date.

In any event, Prof. Shishoo explained that the passage in Tortora relied on by H&M did not concern fusible yarn to be incorporated into a fabric. The passage relates to thermoplastic fibres. Prof. Shishoo stated that these are short fibres which require pressure to bond. In contrast, fusible yarns melt and cool and do not require pressure to bond. Prof. Ellis accepted that the publication was dealing with a different technology.

As to promotion by EMS-Chemie, there was no evidence of general marketing or promotion before the priority date of this particular use of its products to strengthen tubular fabric.

H&M also relied upon two EMS-Chemie sample documents which show the use of fusible yarn in tubular fabric for a brassiere. Neither of the Professors knew anything about these documents and it was conceded that their contents did not form part of the common general knowledge at the priority date. It may be that these documents were produced for a particular customer and were never progressed – the position is unclear. Given that they do not represent common general knowledge, they are of no relevance to the argument advanced by H&M, based as it is on such common general knowledge. H&M suggested that their contents would not have been surprising to the skilled reader at the priority date. Prof. Shishoo disagreed with this suggestion, and I accept his evidence.

Prof. Ellis accepted that the problem referred to in the Patent was a known problem at the priority date and the Patent disclosed a good solution to it (T3/398 and 408). Mr Glenn explained that in 1993 Marks & Spencer “challenged the market” to find a solution to that problem and it took his firm three years to work out a solution. That history is inconsistent with a conclusion that the invention was obvious based on common general knowledge. Indeed, I did not consider that Prof. Ellis was saying that the Patent was obvious on the basis of common general knowledge. See for example his cross-examination at T3/398/21-25:

“Q. So they [M&S] challenged the industry to find a solution to a problem to which you say there was an obvious answer already there?

A.

No, I have not said there was an obvious answer. I said this was an answer.”

In my judgment, whilst the evidence established that fusible yarn was well-known at the priority date, it did not establish that its use to increase penetration resistance in tubular fabric was common general knowledge at that date. On the contrary, this appeared to be a new use of a known material to solve a long-standing problem.

Given that, in a marketed brassiere, the fusible yarn will have melted and cooled, it is difficult to establish the percentage by weight of such fusible yarn. Ideally, one would have samples of fabric, supplied by the manufacturers who made the allegedly infringing items and made to the same weave patterns. Samples containing fusible material could be disassembled, and a simple weighing exercise could identify the percentage of fusible yarn in the material. Comparative tests on samples without fusible yarn and the alleged infringements could identify any increase in resistance to penetration.

As H&M did not manufacture the allegedly infringing bras, it did not know the information as to their composition which would be required to prepare a PPD. Nonetheless, H&M agreed to provide a PPD containing a written description of the products alleged to infringe together with other details such as the process by which the fusible yarn contained within such products was produced, the composition of fusible yarn within such products, all of the processes by which such products were treated, and drawings of the products and their manufacturing processes. The requirement for this PPD was contained at paragraph 9.1 of the Order of Sales J made on 23rd of October 2013. Paragraph 9.2 of that Order required that the PPD should be accompanied by a signed written statement:

“(a)

that the person making the statement was personally acquainted with the facts to which the statement related;

(b)

verifying that the statement was a true and complete description of the products and the processes used in their production;

(c)

containing an acknowledgement that the person making the statement may be required to attend court in order to be cross-examined on the contents of the description.”

Prof. Ellis was given the unenviable task of verifying that the PPD was true and complete. He did so, but made clear that this was based on information provided by the manufacturers of the tubular fabric as to the quantity of fusible yarn contained in the products, which allegedly corresponded with what he had seen from his inspection. The PPD that was originally provided was inaccurate. Following a lengthy series of complaints by Stretchline, a supplemental PPD was served, accompanied by a second witness statement of Prof Ellis, correcting some inaccuracies in the first PPD.

During his cross-examination it emerged that Prof. Ellis did not consider that either of the PPD's was complete and he had not checked the data that had been provided to him. It was clear that he had not appreciated the importance of the PPDs and so had not corrected them when more information came to his attention. This was most unfortunate, but I do not consider that it is fair to make personal criticisms of Prof Ellis for this omission. He was placed in a most difficult position by being required to verify information of which he had no knowledge and he thought (mistakenly) that the preparation of his expert reports was a more important task. In future, the significance of a PPD should be explained with care to the witness who undertakes the task of verifying its accuracy.

One reason for the inaccuracies in the PPDs was because the suppliers of the garments, and in particular Devsel and Rimteks, were asked by Yucel Esra on behalf of H&M, as recorded in an email dated 14 February 2013, "if they can prove that they have not infringed stretchlines (sic) patent." So the suppliers tried to come up with reasons for non-infringement. The information that was provided by the suppliers was then included in the PPDs. As set out below, the percentages of fusible yarn in the tubular fabrics alleged to infringe were understated by the suppliers.

In fact, H&M had obtained samples of tubular fabric, with and without fusible yarn from Devsel, Rimteks and Takefast. In a witness statement dated 28^th August 2015, it was explained by Mr John Hill, H&M’s solicitor, that such samples had been received from Devsel and Rimteks in about October 2013 and from Takefast in February 2014.

On the first day of the trial Mr Caddick complained that these samples had not been disclosed. He was particularly concerned about the Devsel samples with fusible yarn, as the PPDs claimed that the percentage of fusible yarn in the Devsel bras was 1%, significantly lower than the percentages of fusible yarn in the Rimteks and Takefast bras. The Devsel samples were disclosed and disassembled by Stretchline overnight. The results were verified in the witness statement of Mr Pugh, who was not challenged in cross-examination. This exercise showed that the correct percentage of fusible yarn in the Devsel samples was about 5%, approximately five times that stated in the PPDs.

Both sides blamed the other for this regrettable situation. Stretchline initially criticised Mr Hill for a failure to comply with the obligation of disclosure. I did not think that this criticism was justified, not least because the effect of service of a PPD is to relieve the defendant from the obligation to disclose documents relating to infringement. The criticism was withdrawn by Mr Caddick. Mr Burkill suggested that Stretchline should have asked for the samples much earlier, since samples without fusible yarn were referred to in H&M's Notice of Experiments, although no mention was made of samples with fusible yarn. Further, all samples had been referred to in Mr Hill’s statement, served a few months before the trial. Stretchline’s response was that by the end of August 2015 a great deal of time and money had been spent by Stretchline on its own experiments and on pursuing inaccuracies in the PPDs, which would have been saved if the samples had been disclosed at an early stage. In my judgment, both sides made mistakes, and mistakes happen in litigation.

Where a defendant elects to serve a PPD instead of providing disclosure, the courts have stated on a number of occasions that it is essential that it provides true information, sufficient to enable all issues of infringement to be resolved. The must be complete in all relevant areas. This was emphasised most recently by Birss J in Vringo v ZTE [2015] EWHC 818 at [19]-[22]. He adopted the observations of Pumfrey J (as he then was) in Taylor v Ishida [2000] FSR 225 at [22]:

“The criticism to which I subjected the product description, in my judgment, is severe. I wish to repeat that the function of a product description is in all respects equivalent to that of disclosure. The duties of all parties, both the professionals and of the parties themselves, in relation to a product description, are the same as they would be in relation to disclosure.”

The facts of this case show, yet again, the importance of adherence to this duty. I accept that H&M, as a retailer, did not know the relevant facts about the composition of the alleged infringements. However, if a defendant does not admit infringement and elects to pursue a positive case of non-infringement, for example by performing its own experiments, as H&M did in the present case, it needs to find out the relevant facts. It was sensible to request and obtain samples of the allegedly infringing material, with and without fusible yarn. Such samples should have been disclosed at an early stage in the proceedings. A PPD would then have been unnecessary, or limited to information relevant to infringement which could not have been ascertained from the samples.

A similar problem has arisen in relation to declarations of non-infringement made pursuant to section 71(1) of the Patents Act 1977. The section requires that the applicant for a declaration has furnished the patentee with “full particulars in writing of the act in question.” In a number of cases, arguments have arisen about the adequacy of the written particulars. In Minnesota Mining & Manufacturing Co.’s (Suspension Aerosol Formulation) Patent [1999] RPC 135 at 153, Pumfrey J (as he then was) said:

“There is always a risk that the adequacy of a description will be affected by the construction which is placed upon the claim and it is always preferable, in any case of an application for a declaration of non-infringement, to aid the description furnished to the patentee by a sample of the alleged infringement, or by drawings, or whatever.”

In my judgment, this will apply, in many cases, to PPDs. Of course, there will be some cases where the provision of a sample is uninformative, or where there may be doubts about whether that which is provided is in fact a sample of the alleged infringement. However, this case illustrates that, had samples been provided at an early stage, much time and money spent arguing about the adequacy of the PPD would have been saved.

In addition to the Devsel samples, Prof. Ellis was cross-examined about the percentages of fusible yarn specified in the PPDs, based on certain weave diagrams provided to H&M by the suppliers. My conclusions in relation to these percentages are as follows:

On one view, these percentages are not of great importance. Stretchline points out, correctly, that none of the claims of the Patent specify a minimum percentage of fusible yarn. On the other hand, the percentages in the allegedly infringing garments are close to, or within, the preferred range specified in the description. This is relevant to the argument, advanced on behalf of H&M, that it has not been proven that this quantity of fusible material results in the formation of a penetration barrier, within the meaning of the claims of the Patent. It defeats any argument that the percentage of fusible yarn in the alleged infringements is de minimis.

In its opening skeleton, Stretchline accepted that the fusible yarn in the Devsel, Rimteks and Takefast bras did not form a continuous or semi-continuous layer or liner on the inner surface of the tubular fabric. This concession followed from Stretchline’s evidence that the formation of such a liner from fusible yarn was not practical in woven tubular fabric. Accordingly, Stretchline accepted that, on H&M’s construction, none of the products fell within the claims of the Patent.

On the other hand, on Stretchline's construction, which I have accepted, it seems to me that on the basis of the evidence of both Prof. Shishoo and Prof. Ellis, the Devsel, Rimteks and Takefast bras all fall within the claims of the Patent, on a balance of probabilities. In particular, Prof Ellis emphasised in his report that the inclusion of a fusible yarn will operate to bond a fabric together more tightly (Ellis [26], [27] and [32]). It is not disputed that the allegedly infringing garments contain fusible yarn woven into the weft, as shown in Figure 1 of the Patent. I have found that the percentages of fusible yarn in the alleged infringements are significant. It follows that after heating and cooling, the fusible yarn will most likely operate to bond other filaments and yarns across the full width of the fabric, which will increase resistance of the fabric to penetration, and form a penetration barrier within the meaning of claim 1.

This conclusion is reinforced by the fact that, as Prof. Shishoo explained in his first report, the only purpose of inclusion of fusible yarn in the weft is to increase the fabric’s resistance to penetration. Fusible yarn is expensive, and its inclusion in the weft uses far more of the material than would be required merely to create a fused edge to the fabric. No explanation was offered as to why fusible yarn was woven into the weft of all the alleged infringements, other for the purpose of increasing resistance to penetration of the tubular fabric by the underwire.

Stretchline has performed various experiments in order to establish infringement. It relies on a number of SEM images which, it claims, show the presence of fused yarn in the tubular fabric of the garments in issue, which has melted and cooled to form adhesive bonds within the fabric structure. In my judgment, certain SEM images do show such adhesive bonds. This is only to be expected. It is common ground that the fusible yarn is in every weft yarn of the tubular fabric of the alleged infringements. There are about 40 fusible yarn threads stretching across the width of the fabrics in every centimetre of the tubular portions. After melting, these threads fuse around the weft yarns and form bonds between the weft and the warp.

H&M points out that there are a number of images when no fusing is visible. However, many of these images were of the surface of the tubular fabric where fusing cannot be seen as it is hidden by the yarn filaments. This also explains why it was difficult to obtain SEM images which show the relevant bonding.

H&M also submits that, even if there are some isolated fragments where there is adhesive bonding, they are not representative of the tubular fabric as a whole, and do not show that a penetration barrier has been formed, even on Stretchline’s construction. I reject this submission. A significant amount of fusible yarn has been included in all of the alleged infringements. The purpose of such inclusion is to increase the resistance to penetration by the underwire of the tubular fabric. In my judgment, this purpose has been achieved in all bras which are alleged to fall within the claims of the Patent, and this conclusion is consistent with the evidence of both experts.

Stretchline has also performed pin penetration tests to evaluate whether the inclusion of fusible yarn in the alleged infringements has resulted in increased resistance to penetration. The test used is known as the M&S pin penetration test. This is now a standard test used in the industry for this purpose. H&M objects that this is not the test that is referred to in the Patent for determining increased resistance to penetration. This is unsurprising as the M&S test was developed subsequent to the date of filing of the Patent. I do not consider that this is a reason to disregard the results of the M&S test. There is nothing in the body of the specification or in the claims to suggest that the L+M sewability test must be used. The purpose of the M&S test is to show, as a matter of fact, that resistance to penetration has increased as compared with conventional fabric, and in my judgment any conventional industry test could be used to establish this fact.

The evidence of Mr Glenn, who was in part responsible for development of the M&S test, is that tubular fabric without fusible yarn would achieve a penetration resistance of about 11 kgf or less. I have rejected the attack on the veracity of Mr Glenn. I accept his evidence as to the usual force required to achieve penetration of conventional tubular fabric in the M&S test.

There is a helpful table in Prof. Ellis's evidence which shows the results of the M&S pin penetration tests on the alleged infringements. The Rimteks bras were in the range 16.3-20.5 kgf; the Devsel bras were in the range 18.3-22.05 kgf; and the Takefast bras were in the range 20.3-31.2 kgf. These results are consistent with the fact that the Rimteks bras contain the lowest percentage of fusible yarn, the Takefast bras contain the highest percentage, and the Devsel bras are in the middle. These results are considerably higher than the 11 kgf figure for conventional fabric, and indicate considerable increased resistance to penetration as a result of adhesive bonding of yarn and filaments on melting and cooling of the fusible yarn. The results are to be expected, given the evidence of the experts that even a small quantity of fusible yarn will increase a fabric’s resistance to penetration.

For the reasons set out above, I conclude that each of the Devsel, Rimteks and Takefast bras which are the subject of this action fall within the claims of the Patent. The sale of such bras by H&M was made in breach of the Settlement Agreement.