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Court of Appeal overturns IPEC's decision finding that detergent resistant washbowl patent is invalid

Posted on 25 September 2023

Earlier this year, we wrote an article about a case (Vernacare v Moulded Fibre Products (MFP)) concerning the validity and infringement of two UK patents relating to the shape and composition of disposable moulded paper pulp washbowls, which are detergent resistant, meaning they can be used by healthcare professionals to hygienically clean patients (GB 2446793 (the "793 Patent") and GB 2439947 (the “947 Patent”)).

The decision of the Intellectual Property Enterprise Court (IPEC) was particularly interesting as it was the first time that the "Formstein defence" had been applied in UK proceedings. As a result, the 793 Patent was found valid, albeit not infringed.

The Defendant, MFP, had admitted that, if the 947 Patent was valid, it was infringed as its washbowl fell within the relevant claims. However, it argued that the 947 Patent was invalid for being obvious over two Japanese patent applications that included the use of fluorocarbons to make pulp food containers resistant to oil and water.

The IPEC determined that there was nothing in the prior art that would make it obvious to the skilled person to add a fluorocarbon to the pulp mixture of a disposable paper pulp washbowl and held that the 947 Patent was valid. MFP has now successfully appealed this finding on the basis that the trial judge had incorrectly identified the inventive concept of Claim 1 of the 947 Patent and also wrongly found Claim 9 to be independently valid.

The Appeal

MFP argued that Claims 1 and 9 of the 947 Patent were invalid for being obvious over an earlier patent application (Shimooka) for single use food containers, which contained fluorocarbons to enhance their oil, water and grease resistance. Shimooka disclosed a wide range of shaped articles, including tableware.

Claim 1

Claim 1 of the 947 Patent refers to an open-topped washbowl that is manufactured from a mouldable paper pulp composition, which includes a detergent resistant binding agent, comprising a fluorocarbon. MFP argued that the IPEC judge wrongly determined the inventive concept of Claim 1, by introducing an illegitimate purpose-based element, i.e., that a detergent resistant washbowl can be made using a fluorocarbon agent. The trial judge had construed the inventive concept as being an appreciation that a fluorocarbon could be added to a composition of mouldable paper pulp to make a disposable washbowl detergent resistant. Construing the claim in this way, however, excluded a detergent resistant washbowl that was made without the purpose of being detergent resistant. The Court of Appeal agreed with MFP that this purpose-based construction was incorrect. In fact, the inventive concept of claim 1 was simply a washbowl made from a paper pulp composition that included a fluorocarbon.

The Court of Appeal went on to conclude that Shimooka made it obvious to a person skilled in the art to make an article, i.e. a bowl, that met the requirements of Claim 1. It did not matter that Shimooka did not specify the additional benefit of being detergent resistant. Further, the cup-shaped food container in Shimooka had the same characteristics as a washbowl, namely that it could hold enough water to wash a patient, albeit not a full bed wash.

In reaching its conclusion on this part of the appeal, the Court of Appeal took into account the decision in Hallen v Brabantia, a case about bonus effects for inventions, which determines that if an invention is obvious for one purpose (i.e., here, making a washbowl using a paper pulp composition that included a fluorocarbon, which is resistant to oil, water and grease), an additional unexpected benefit for another purpose (i.e., being detergent resistant) does not make it inventive. Claim 1 was therefore invalid for obviousness.

Claim 9

The IPEC judge had found that Claim 9 of the 947 Patent was independently valid. The claim added a requirement for an amount (of which a wide range was provided) of fluorocarbon to be present in the mouldable paper pulp composition.

The Court of Appeal concluded that the IPEC had not considered the expert evidence regarding imparting detergent resistance and also did not consider the obviousness of claim 9 on the basis of MFP's inventive concept. For these reasons, the Court of Appeal was entitled to re-evaluate the obviousness of Claim 9.

The Court of Appeal considered that, although using fluorocarbons to produce detergent resistance was not part of the common general knowledge, the judge had found as a fact that the skilled person would, when a formulation issue arose, consult a specialist. When seeking specialist advice, the outcome that the skilled person was seeking to achieve by adding the fluorocarbon to the formulation did not matter.

Further, it was also common ground that products made according to the teaching in Shimooka would in fact be detergent resistant (even though detergent resistance was not specified in Shimooka). This demonstrated that it was unlikely that a different amount of fluorocarbon was needed to achieve detergent resistance when compared with oil, water and grease resistance. Accordingly, although the expert evidence was given on the basis of achieving detergent resistance and not the other purposes, this did not matter as the amount of fluorocarbon was not different for the two purposes. Therefore, the expert's evidence that the wide range of relative volumes of carrier in Claim 9 would be obvious ones to try was fatal and the claim was invalid.


It is noteworthy that Hallen v Brabantia was not cited to the IPEC, as the principle from this case (which is that an invention may be rendered obvious by a prior disclosure even if it does not articulate all the benefits of the claimed invention) was key to the Court of Appeal finding that the relevant claims of the 947 Patent were invalid. Indeed, the Court of Appeal judge commented that it was "unfortunate" that the IPEC judge had not been referred to it.

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