The German Federal Patent Court has revoked Zeon’s patent EP 3 800 714 in its entirety, citing insufficient disclosure and added matter. This decision effectively stalls the ongoing patent infringement litigation between Japan-based Zeon and Dutch competitor Arlanxeo, a subsidiary of Aramco, concerning synthetic rubber materials used in rechargeable battery cathodes.
Revocation of EP 714 and the Impact on Infringement Litigation
The 3rd Senate of the Federal Patent Court, presided over by judge Walter Scharamm, confirmed a preliminary opinion issued in July 2025. The court found that the technical teaching within the patent was not sufficiently reproducible, leading to the total revocation of the patent rights. This ruling directly impacts the infringement case previously filed by Zeon at the Munich Regional Court (case ID: 21 O 9713/24) in August 2024.
Following the patent court’s nullity action (case ID: 3 Ni 1/25), the Munich Regional Court had already stayed the infringement proceedings. With the patent now revoked, the future of the infringement claim remains uncertain, pending potential appeals. The litigation in Munich has seen a shift in judicial oversight, with presiding judge Hubertus Schacht taking over the case following the transfer of judge Georg Werner to the Unified Patent Court.
Did you know?
In patent law, “insufficient disclosure” occurs when a patent application fails to provide enough information for a person skilled in the relevant technical field to reproduce the invention without undue burden. This is a common ground for nullity actions in German patent courts.
Legal Representation and Strategic Maneuvers
The legal battle has featured high-profile firms handling complex technical and litigation strategies. Zeon relied on a dual-firm approach: patent attorney firm df-mp managed the technical aspects and nullity proceedings, with partners Elisabeth Greiner and Holger Schimmel leading the effort. For the infringement proceedings at the Munich Regional Court, Zeon retained Alexander Ritter and Moritz Sutterer from Morgan Lewis & Bockius.
Arlanxeo took a collaborative approach, utilizing a mixed team from Mitscherlich. Litigator Markus Bölling and patent attorney Sebastian Strych spearheaded the nullity action and represented Arlanxeo in the Munich infringement hearings. They worked in coordination with Arlanxeo’s in-house legal team, led by Global Head of IP Thiemo Marx and senior IP counsel Lars Müller.
Future Trends in Battery Material Patent Litigation
Frequently Asked Questions
- Why was Zeon’s patent revoked? The Federal Patent Court revoked EP 714 due to insufficient disclosure and added matter, meaning the invention could not be reliably reproduced based on the provided documentation.
- What happens to the infringement proceedings? The Munich Regional Court had already stayed the proceedings pending the nullity outcome. With the patent revoked, the claim is currently stalled.
- Can the decision be appealed? Yes, the decision of the Federal Patent Court is subject to appeal.
- Who represented the parties? Zeon was represented by df-mp (patent attorneys) and Morgan Lewis & Bockius (litigation). Arlanxeo was represented by a mixed team from Mitscherlich.
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