Zusammenfassung von EPC2000 Art 123(2) für die Entscheidung T1099/21 vom 15.03.2023

In T 1099/21, claim 1 of the application as originally filed essentially related to a coating composition comprising a microencapsulated biocide and a free (i.e. not microencapsulated) isothiazolone biocide or antifouling agent. The feature relating to the upper concentration limit of the free isothiazolone biocide or antifouling agent was 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 board concluded that the functionally defined upper limit of the concentration range for the free isothiazolone biocide was 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. Thus, as correctly pointed out by the appellant, this functional feature was disclosed in the application as filed as an essential feature of the invention and did not merely relate to a preferred embodiment thereof. Claim 1 of the main request was amended by deleting the functionally defined upper limit of the concentration range for the free isothiazolone biocide from claim 1 as filed. As a result, the upper limit was defined numerically ("to 15% by weight of the film forming polymer or binder solids"). The board explained that, 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 resulted in an extension of the claimed subject-matter beyond the content of the application as filed. The respondent argued that the functional feature of claim 1 as filed had not been deleted but replaced by the numerical upper limit. The board did not agree. It was very readily conceivable, and this was acknowledged by the respondent at the oral proceedings, that claim 1 of the main request encompassed film forming polymers for which amounts of free isothiazolone biocides close or identical to the numerical upper limit of 15% actually reduced the glass transition temperature by more than 20°C, contrary to claim 1 as filed. The respondent also submitted that the plasticising effect of certain biocides on film forming polymers was well-known to the skilled person. The wording of claim 1 of the main request stated the concentration of the free isothiazolone biocide in relation to the weight of the film forming or binder solids. This was a pointer to the skilled person that the coating composition of claim 1 of the main request should not contain too much free isothiazolone biocide, depending on the film forming polymer actually used. For this reason, compositions in which, for example, concentrations of 15% of free isothiazolone biocide caused a Tg reduction of more than 20°C did not actually fall within the subject-matter of claim 1. The board disagreed. The subject-matter of a claim was determined by its wording, which in the present case provided for an explicit upper limit of 15% for any film forming polymer. Thirdly, the respondent 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 Art. 83 and 84 EPC. The board did not agree with this contention. It was already clear from the wording of the functional feature that it was 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 did not define an exact numerical upper limit might be due to the fact that the actual upper limit depended on the composition under consideration. However, any lack of clarity that might arise from an ambiguity in an application as filed was to the detriment of a patent proprietor, who was ultimately responsible for the drafting of the application as filed and its claims. The fact that a feature in the application as filed was unclear could not therefore justify or excuse the complete deletion of the unclear feature or its replacement by another feature if this resulted 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) could not have any influence on the outcome of the assessment of the ground for opposition under Art. 100(c) EPC. The board explained that the above reasoning for claim 1 of the main request applied to all the auxiliary requests. None of the auxiliary requests were allowable because the subject-matter of claim 1 of each of the auxiliary requests extended beyond the content of the application as filed.