In T 169/96
the examining division was of the opinion that in the case before it such a single general inventive concept was not present, since the structural alternatives comprised by formula A, which had a common property, did not share a common significant structural element, and, according to the EPO Guidelines C-III, 7.4a, which referred to the text of R. 30 EPC 1973 (old version as in force until 31.5.1991), a common new use of known and novel chemical compounds was not in itself sufficient to establish a common inventive concept within the meaning of Art. 82 EPC 1973
. The board noted that the fact that one claim also comprised a known compound, not covered by another claim 2, was of no relevance to the question of unity, because R. 30(b) EPC 1973 (old version as in force until 31.5.91; also under the version in force thereafter) did not require that there must be a common concept unifying different "means" according to it. In other words, it was not relevant in these circumstances that the three different classes of chemical compounds identified by the examining division comprised completely different chemical structures of a residue. The board observed that the above-mentioned Chapter of the Guidelines, as well as Annex B, Part 1(f) of the PCT Administrative Instructions (this corresponds to Annex B, paragraph (f) of the PCT Administrative Instructions, as in force from 1.7.2008) concerning the examination of unity of invention of so‑called Markush‑type claims rightly stated that the said significant structural element might consist of a combination of individual components linked together. It was not stated there that the combination of individual structural elements had to be novel per se, nor did such a requirement follow from Art. 82 EPC 1973
. Rather it followed from that guideline that this expression meant that in relation to the said common property or activity there had to be a common part of the chemical structure which distinguished the claimed compounds from known compounds having the same property or activity. In the present case no state of the art was cited which related to chemical compounds which were known to be useful for the production of polymeric compositions of enhanced oxidative stability. The combination of the peroxide group and the residue "An" which was responsible for conferring the oxidative stability, however, distinguished the compounds of claim 2 from all chemical compounds conventionally used as antioxidants in polymeric compositions, on the one hand, and from all compounds conventionally used as polymerisation initiators, on the other hand.