Court of Appeal affirms interpretation of product-by-process features in claims, and clarifies applicable law pre-June 2023

Knaus Tabbert AG v Yellow Sphere Innovations GmbH

UPC-CoA-365/2025, UPC-CoA-367/2025, decision of 17 August 2026

The Court of Appeal has upheld the first instance decision¹ of the LD Düsseldorf finding the patent EP 3356109, belonging to Yellow Sphere Innovations GmbH and another, valid and infringed by Knaus Tabbert AG.

Product-by-process features

A key issue in the case was the interpretation of a “product-by-process” feature in a claim.  The patent EP 3356109 relates to a frame for a vehicle having a structural part which according to claim 1 must be "produced as a cast part in a mould", formed by a self-swelling foam resin, and at least partially coated on the outside with a protective layer. Knaus Tabbert asserted that their process involves the use of two moulds – one to form the inner foam resin portion, and a further one to apply the protective layer.

The Court of Appeal agreed with the LD Düsseldorf that the inclusion of a specific manufacturing process in a product claim does not alter the fact that it is a product claim, with the process features serving merely to provide an indirect, more detailed description of the product.  The claim is limited to products actually produced by the specified process only if the specific characteristics of the product can only be achieved by means of the specified manufacturing process.

In this case, the Court of Appeal considered that the limitation "produced as a cast part in a mould" should be understood only to exclude structural parts produced by extrusion, and that the three-dimensional shape of the structural component is essentially defined by cast foam, without discernible post-processing with regard to the three-dimensional shape, such as milling or grinding.  It was not necessary for the structural part to be actually manufactured using just one mould.

Accordingly, the Court of Appeal agreed with the LD Düsseldorf that the product-by-process feature was satisfied.

Jurisdiction

The Court of Appeal rejected the assertion of Knaus Tabbert that the UPC does not have jurisdiction over claims arising from acts of infringement committed prior to the entry into force of the UPC Agreement.  It emphasised that the question of jurisdiction is separate from that of applicable law.  The Court stated that for reasons of legal certainty, the court must be in a position to decide whether it has jurisdiction on the basis of the UPCA and the Brussels Ia Regulation alone, without having to enter into an examination of the merits.

Applicable law

The Court of Appeal considered at length what should be the law applicable to facts occurring before 1 June 2023, noting that rules of substantive law must be interpreted as applying to circumstances that arose prior to their entry into force only in so far as it is clear from their wording, their purpose or their structure that they are intended to have such an effect.  It concluded that the applicable law differed depending on the legal remedy sought.

In respect of an injunction, the Court considered that the set of facts is only concluded upon the final and genuine cessation of the infringement.  Therefore, where the infringer has not definitively ceased the infringing acts before 1 June 2023, the prohibition on retroactive effect does not preclude application of the UPC Agreement and in particular Article 63 thereof.  The same logic applies to remedies under Article 64(2)(b), (c), (d) and (e) UPCA (recall and destruction).

However, for damages, each individual patent infringement gives rise to a claim for damages, so the facts of the case are concluded once the individual act has ceased.  Therefore, acts that were completed before 1 June 2023 must be assessed under national law.

Meanwhile, for provisional protection (compensation for acts carried out after publication of the application but before grant), national law applies, irrespective of the date.  Noting that this is “contrary to the view held by some”, the Court observed that the UPC Agreement does not provide a substantive legal basis for such claims: Article 32 (1)(f) UPCA merely allocates jurisdiction in this respect, while Article 67 EPC allows contracting states a margin of discretion in how such protection is assessed.

The Court went on to say however that for remedies provided by the Enforcement Directive, it can be assumed that national law corresponds to that set out in the Directive.  In any case, if national law is to be invoked, the burden of proof regarding national law lies with the party invoking the provision of national law.

Outcome

Applying these principles the Court of Appeal rejected the appeal with respect to the finding of infringement.  The appeal relating to the validity of the patent was also dismissed.