## Facts

- A patent owner held a European patent covering laundry detergent compositions containing surfactant, a peroxygen bleach capable of yielding hydrogen peroxide, and specified bleach activators, with a defined molar ratio between peroxide and activator.
- The application was initially refused, but a prior appeal during examination resulted in an order to grant the patent.
- After grant, an opponent filed an opposition alleging lack of novelty and lack of inventive step based on cited prior art relating to bleaching detergent compositions.
- The Opposition Division revoked the patent, finding the granted main claim anticipated by prior art and concluding the owner’s fallback claims lacked inventive step.
- On appeal, the patent owner argued that the earlier examination appeal decision conclusively settled novelty and inventive step and barred re-litigation in opposition.

## Issues

1. Whether a Board of Appeal decision issued in ex parte examination proceedings has binding (res judicata) effect in later inter partes opposition proceedings involving a new party.
2. Whether the patent’s main claim was novel over the cited prior art.
3. Whether the patent owner’s auxiliary (amended) claims involved an inventive step over the closest prior art.

## Decision

- The Board held that an examination-appeal decision has no binding (res judicata) effect in subsequent opposition proceedings or appeals from them.
- The Board affirmed that the main request lacked novelty over the cited prior art and could not be maintained.
- The Board held the auxiliary request involved an inventive step as a non-obvious alternative to the closest prior art.
- The appeal was allowed in part, and the patent was maintained in amended form on the basis of the auxiliary request.

## Legal Principles

- Decisions in ex parte examination proceedings do not bind later inter partes opposition proceedings; a new opponent is entitled to a fresh review of patentability.
- Res judicata does not apply across distinct procedural frameworks where party identity and procedural context differ.
- Novelty fails when prior art directly and unambiguously discloses the claimed subject matter to the skilled person.
- Inventive step is assessed using a closest-prior-art analysis that identifies distinguishing features, defines an objective technical problem, and asks whether the solution would have been obvious to the skilled person.
- A patent may be rejected on a broad main claim yet maintained on narrower auxiliary claims that add non-obvious limitations.

## Conclusion

The Board rejected claim-preclusion arguments based on an earlier examination appeal, upheld revocation of the patent’s main claim for lack of novelty, and preserved the patent in amended form because the auxiliary claims constituted a non-obvious alternative over the closest prior art.


Procter & Gamble Co. v. Unilever PLC, No. T 167/93 (EPO Tech. Bd. App. May 3, 1996)