Zusammenfassung von EPC2000 Art 056 für die Entscheidung T1750/19 vom 21.09.2022

In T 1750/19 the board found that D4 was a suitable starting point for the assessment of inventive step. The appellant, on obviousness, argued that the skilled person knew from D8 that basically any low molecular weight compound having two functional groups that react with isocyanate may be used as a chain extender, and that as the lactic acid-ethylene glycol dimer in Example 17 of D1 was a diol, the skilled person would have considered it to be an alternative to the chain extender in D4 1,4- butenediol. The board disagreed, finding that D4 could only be combined with Example 17 of D1 with hindsight; the skilled person had no motivation to replace the chain extender in Example 2 of D4 with the lactic acid-ethylene glycol dimer in Example 17 of D1. The board stated it was apparent that the teaching of D4 and the teaching of D1 were incompatible and that the skilled person starting from D4 and seeking an alternative polyurethane had different options for modifying the original polymer, one of which was replacing the chain extender with an alternative chain extender. Should the skilled person select this option, they would certainly not turn to D1. They would look for compounds already known as polyurethane chain extenders rather than selecting a compound having a different function in a document containing teaching that is incompatible with the starting point. The common general knowledge disclosed in D8 did not change this conclusion; D8 would not give the skilled person any incentive to select a compound from D1, which did not contain any teaching relating to chain extenders, just because the compound contained two hydroxyl groups. The board found that the subject-matter of claim 1 was inventive and met the requirements of Art. 56 EPC. This was also the case for the other independent claims of the main request.