Zusammenfassung von EPC2000 Art 056 für die Entscheidung T1994/20 vom 24.11.2023

In T 1994/20 the appeal lay against the decision of the opposition division to reject the opposition. It was an object of the invention to provide an improved polyolefin composition suitable for the production of a pressure pipe with improved pressure resistance as well as impact properties. D3 related to pressure pipe multimodal polyethylene compositions and material D - which the board took as the closest prior art - was therein described as having good non-sagging properties, as well as excellent physical properties. The parties took differing positions as to which problem could be considered to be successfully solved by the subject-matter of operative claim 1 and comparative tests were offered by the respondent in support of its position. The board found the material used in the comparative example of the specification differed in many aspects from the material of the closest prior art. This in itself did not invalidate the respondent's arguments based on the comparison made in the specification, since the possibility of using a comparison made with a variant of the closest prior art has been recognised by the Boards of Appeal as early as in T 35/85. However, since the question to be answered concerned the problem successfully solved over the closest prior art by the claimed subject-matter, the board held it was per se not sufficient to demonstrate that an effect or advantage resulting from the distinguishing feature was observed in the context of a variant of the closest prior art used as reference example in the comparative test. It had to additionally be credible that the same effect or advantage took place in the context of the closest prior art, i.e. irrespective of the modification of the closest prior art operated to prepare the reference example of the comparative test. Concerning the present case, in the absence of any technical explanation for the technical effects resulting from the use of a LMW fraction having a lower MFR2 of not more than 100 g/10 min. in the context of the comparative example of the patent in suit, there was no apparent reason to expect that the same effects were also obtained in the context of the closest prior art, which substantially differed therefrom. Consequently, the respondent had not presented any corroborating evidence or explanations rendering it credible that the purported technical effect was actually achieved. Accordingly, any such advantage of the claimed polyethylene composition over the closest prior art could not be taken into account for the purpose of assessing inventive step. Thus, the board held the problem underlying the claimed invention had to be reformulated as the mere provision of a further polyethylene composition for use in pressure pipes.