CABINET CHAILLOT
PATENTS TRADEMARKS DESIGNS
French Patent & Trademark Attorneys - European Patent Attorneys - Representatives before EUIPO
ISO 9001 CERTIFIED
This decision concerns the appeal filed by the opponent (appellant) against the opposition division's decision to reject the opposition against European patent No. 1 834 524 (patent).
Claim 1 as filed essentially relates to a coating composition comprising a microencapsulated biocide and a free (i.e. not microencapsulated) isothiazolone biocide or antifouling agent.
Of particular interest in the present case is the feature which relates to the upper concentration limit of the free isothiazolone biocide or antifouling agent. This upper limit is defined functionally in terms of a result to be achieved ("up to a concentration that does not reduce the glass transition temperature of the film forming polymer by more than 20 °C").
The application as filed identifies 4,5-dichloro-2-n-octyl-3(2H)-isothiazolone (DCOIT) as an important biocide for marine antifoulant paints. However, its plasticising effect, i.e. lowering the glass transition temperature (Tg) of polymeric binders, is considered a disadvantage, as it leads to a reduction in the integrity of the paint film and often to an increase in the drying time of the antifoulant paint.
Against this background, it must be concluded that the functionally defined upper limit of the concentration range for the free isothiazolone biocide is set out as being necessary for solving the technical problems addressed by the application as filed, namely maintaining the integrity of the paint film and avoiding prolongation of the drying time of the coating composition. This means that this functional feature is disclosed in the application as filed as an essential feature of the invention.
In claim 1 of the main request, the functionally defined upper limit of the concentration range for the free isothiazolone biocide from claim 1 as filed has been deleted. The upper limit is now defined numerically ("the concentration of free isothiazolone biocide is from 0.25 percent to 15 percent of the weight of the film forming polymer or binder solids ").
According to established case law, deleting from an independent claim a feature which the application as filed consistently presented as being an essential feature of the invention results in an extension of the claimed subject-matter beyond the content of the application as filed under Article 123(2) or Article 100(c) EPC. As set out above, the functional feature deleted in claim 1 of the main request is essential in the context of the application as filed.
The respondent argued that the functional feature of claim 1 as filed had in fact not been deleted but replaced by the numerical upper limit. The application as filed disclosed the plasticising effect of DCOIT. Therefore, it was clear that the only quantitative teaching in the application as filed relating to DCOIT, stating that "[i]n one embodiment, the free DCOIT is added in an amount of from 0.25% to 15% of the weight of the film forming polymer or the binder solids", was meant to address this plasticisation problem and the reduction in Tg and was applicable to the invention of claim 1 as filed.
The board does not agree with this analysis. The application as filed does not disclose that the numerical upper limit of 15% is meant to be the same as the functionally defined upper limit of claim 1 as filed or that the latter is always complied with when the concentration of the free isothiazolone biocide is <= 15%. It is very readily conceivable that claim 1 of the main request encompasses film forming polymers for which amounts of free isothiazolone biocides close or identical to the numerical upper limit of 15% actually reduce the glass transition temperature by more than 20 °C, contrary to claim 1 as filed.
The respondent also argued that the functional feature in claim 1 as filed could not be meaningfully interpreted by the skilled person as defining a boundary. The replacement of the functional feature in claim 1 as filed by the numerical upper limit in claim 1 of the main request was made to address the examining division's objections in this respect under Articles 83 and 84 EPC and should be considered allowable.
The board cannot agree with this contention. It is already clear from the wording of the functional feature that it is intended to define an upper limit for the concentration of the free isothiazolone biocide in the coating composition. The fact that claim 1 as filed does not define an exact numerical upper limit may be due to the fact that the actual upper limit depends on the composition under consideration. However, any unclarity that may arise from an ambiguity in an application as filed is to the detriment of a patent proprietor, who is ultimately responsible for the drafting of the application as filed and its claims. The fact that a feature in the application as filed is unclear cannot therefore justify or excuse the complete deletion of the unclear feature or its replacement by another feature if this results in an extension beyond the content of the application as filed. In fact, what prompted a patent proprietor to make a particular amendment to the claims (in this case to address the examining division's objections) cannot have any influence on the outcome of the assessment of the ground for opposition under Article 100(c) EPC.
The respondent did not put forward any arguments as to from where in the application as filed the combination of features of claim 1 of the main request might be directly and unambiguously derivable.
Hence, the subject-matter of claim 1 of the main request extends beyond the content of the application as filed and the ground for opposition of Article 100(c) EPC prejudices the maintenance of the patent as granted.
The patent is revoked.