Prior use infringement defence at the LD Munich: the UPC puts its German hat on (UPC_CFI_114/2024; UPC_CFI_448/2024)

Due to the lack of specific provisions in the EPGÜ, national law must be referred to in order to answer the question of the binding effect of a final judgment dismissing the national action for annulment under Art. 24.1(e) EPGÜ.

Relevance of the decision

The Munich Local Division UPC decision of 10 October 2025 (Heraeus v Vibrantz, EP 3 215 288 B1) shows that before the UPC the prior use defence is not a unitary concept but a country‑by‑country defence imported from each national law via Article 28 UPCA.

The court held that Vibrantz’s sintering paste literally and directly infringed the patent as amended. As an aside, it is interesting that direct infringement was found at all as Vibrantz was distributing the paste but not using it for “solid joining” as required by the claims. This seems to be another example of a relatively broad approach to direct infringement taken by the UPC, as discussed here. 

Manufacture and distribution of the relevant products in Germany were undisputed. But the court still concluded that there was no enforceable infringement because of a successful prior use defence for Germany and lack of proof of infringing acts in other states.

Prior use defence as applied by the UPC

Article 28 UPCA provides that any person who would have had a prior use (or possession) right if a national patent had been granted in a Contracting Member State enjoys the same rights before the UPC in that State but does not define what “prior use” is.

The court treated Article 28 as a “referral rule": the content, conditions and scope of the prior use defence are entirely determined by the law of the particular state for which the defence is invoked, and the defence only operates territorially in that state.

For Germany, the court applied German prior use principles (mirroring § 12 PatG), requiring that before the priority date the defendant had already begun using the invention or made the necessary preparations for such use in Germany. 

The burden of proof lay on Vibrantz, who produced detailed evidence of consistent manufacture and sale of the sintering pastes before the priority date. 

The court held it was not necessary that Vibrantz had recognised the products’ technical parameters (here: the mathematical product of tapped density, and specific surface area, of the metal particles of component (A) in the range of 50000 to 80000 cm⁻¹) at that time: it was enough that the product inherently met them and that the intended technical effect (solid joining) was achieved. 

As a result, Vibrantz was entitled to continue those acts in Germany.

The court found that Heraeus had not substantiated actual infringing acts in other UPC states (alleged marketing to France and Italy was not proven), so no infringement was found.

This decision shows that before the UPC the prior use defence is not a unitary concept but a country‑by‑country defence imported from each national law via Article 28 UPCA. As national law regarding prior use still significantly differs regarding requirements, scope, transferability etc., outcomes may diverge between UPC states even within a single case. 

Claim 1 (amended form)

1. Use of a metal sintering preparation for the solid joining of components, wherein the metal sintering preparation comprises 

(A) 50 to 90 wt% silver in the form of particles, wherein the metal particles are in the form of flakes or an irregular shape, wherein the metal particles have a coating comprising at least one organic compound selected from the group consisting of free fatty acids, fatty acid salts and fatty acid esters, and 

(B) 6 to 50 wt% of one or more organic solvents selected from the group consisting of terpineols, N-methyl-2-pyrrolidone, ethylene glycol, dimethylacetamide, 1-tridecanol, 2-tridecanol, 3-tridecanol, 4-tridecanol, 5-tridecanol, 6-tridecanol, isotridecanol, unsubstituted 1-hydroxy-C16-C20 alkanes with the exception of a methyl substitution at the penultimate carbon atom. comprising dibasic esters, glycerol, diethylene glycol, triethylene glycol and aliphatic hydrocarbons with 5 to 32 carbon atoms, characterized in that the mathematical product of tapped density, determined according to DIN EN ISO 787-11 : 1995-10, and specific surface area, determined according to DIN ISO 9277 : 2014-01, of the metal particles of component (A) is in the range of 50000 to 80000 cm⁻¹.