Patent infringement: H&M v Stretchline
Stretchline Intellectual Properties Limited v. H&M Hennes & Mauritz Limited  EWCA Civ 199.
The Court of Appeal recently dismissed an appeal made by H&M that they had breached the terms of a Settlement Agreement previously entered into with Stretchline. The judgments at first instance and on appeal considered, in detail, the construction of a patent and the concept of common general knowledge was highlighted as a prevailing factor. H&M's construction was ultimately rejected on the basis that it did not reflect the common general knowledge and consequently the appeal made was dismissed.
In 2010, Stretchline brought proceedings against H&M for infringement of a patent. The patent in question concerned tubular fabric which has particular use in underwiring, most commonly in bras ("the Patent"). The two parties entered into a Settlement Agreement in which H&M agreed not to deal in any product which fell within any claims of the Patent. However, on 28 March 2013, Stretchline brought a further action against H&M and it was alleged that the clothing brand were selling bras which fell within the Patent. It was further alleged that H&M had breached the terms of the Settlement Agreement. H&M counterclaimed its position by stating that the Patent was invalid. This however was struck out on the basis that the terms of the Settlement Agreement prevented H&M from raising future claims in respect of the Patent's validity. Stretchline decided to discontinue the infringement claim and proceeded only to pursue H&M for the breach of the Settlement Agreement.
The Patent itself aimed to provide a solution to the issue to fabric tubing used for underwire in garments such as bras. The first claim of the Patent was a process claim which specified "a method for making a tubular fabric comprising providing a support yarn and elastomeric yarn; characterised in that a fusible yarn is also provided and in that the yarns are formed into tubular fabric whereby the fusible yarn is arranged within the fabric tube so that it is capacity of forming a penetration barrier".
It was not intended however for the fusible yarn to only be used in underwiring for bras but rather for all tubular fabric. The Patent specification makes reference to a "durable inner lining" and it was this aspect of the specification that H&M relied on in support of their construction of the Patent. However the Patent specification also describes the process for making the tubular fabric which involved incorporating the fusible and elastomeric yarns. H&M's position was that the invention created a separate inner lining whereas Stretchline maintained that the tubular fabric was a woven blend of both materials.
It is well established that the approach to construction of patent specifications is to determine what the skilled person would understand the patentee to be using the language of the claim to mean. In his judgement, Henry Carr J considered the concept of common general knowledge; firstly by considering the properties of a fusible yarn and that the normal function of a fusible yarn is, on melting and cooling, to bond fibres together in order to strengthen a material. The second consideration was whether a skilled person would have known as part of his common general knowledge that it was impossible to form a continuous, discrete layer of fusible yarn in a tubular fabric. The judge concluded in favour of Stretchline, that the specification was to be construed as the creation of a combined and bonded barrier rather than a discrete lining.
On upholding Stretchline's construction of the Patent, Henry Carr J conclude that the product being sold by H&M fell within the Patent claims and therefore H&M were in breach of the Settlement Agreement.
H&M appealed the decision and counsel on behalf of H&M submitted that it was wrong to look at the principal claims of the Patent as though they were limited to a tubular fabric in an underwired bra. It was further asserted that the judge had gone too far in saying that the skilled person knew from his or her common general knowledge that it was impossible to make a distinct layer. Counsel on behalf of Stretchline supported the judge's conclusions at first instance and reiterated that, in regard to the common general knowledge, only Stretchline's construction of the Patent specification made sense in that it was not possible to form a fully separate lining, particularly in consideration of the volume of fusible yarn that was detailed in the specification (5-20%).
The appeal judge was satisfied with the conclusions made at first instance by Henry Carr J, namely that the skilled person would know as a matter of their common general knowledge that it was not practical to form a discrete layer from fusible yarn in a woven fabric without about 50% of fusible yarn being used. The judge considered arguments in favour of both parties and that the construction of the Patent specification could suggest a separate continuous membrane, as suggested by H&M or a woven fabric, as suggested by Stretchline but, in consideration of the common general knowledge, concluded that the Patent specification did not allude to a continuous separate layer particularly in light of the quantities of fusible yarn being incorporated into the fabric.
The judgment in this case highlights the importance of approaching the construction of a patent specification from the viewpoint of a skilled person and most notably the common general knowledge.
If you would like further information on this issue, or have concerns regarding patent infringement, then please contact Blake Morgan's Intellectual Property Team.