T 1408/23 - A commercially available polymer

Key points

• "In Example 1 of D1 [the closest prior art], the [pressure-sensitive adhesive (PSA)]  polymer in layer 3 is a polyisobutylene (PIB) and the PSA polymer in intermediate layer 2 is Duro-Tak 87-2852 (paragraphs [0108] and [0109]). The parties did not dispute that Duro-Tak 87-2852 was a well-known and commercially available crosslinked polyacrylate generally used in TTS. This was confirmed by D12, which discloses a selection of commercially available PSA polymers for use in TTS."
• G 1/23 is not mentioned, but this reasoning is consistent with it. G 1/23 was issued a couple of weeks before the (oral) decision in the present case.
  
  
• On the objective technical problem
  " the examples in the patent show that a TTS in accordance with claim 1 retains its adhesive properties during storage. This technical effect has not been compared with the TTS of the closest prior art, but there is no reason to believe that the TTS of claim 1 is superior to or substantially different from the one in Example 1 of D1: as stated in paragraph [0090] of the patent, the maintenance of the adhesive strength during storage is attributed to the fact that the TTS has two PSA layers, a feature that is also present in the TTS of the closest prior art. Consequently, it cannot be concluded that the distinguishing features produce any technical effect over the TTS of the closest prior art."
•  "In the absence of a technical effect over the closest prior art, the objective technical problem has to be defined as the provision of an alternative TTS."
• "The respondent [proprietor] argued that, even if no technical effect has been demonstrated in comparison with the closest prior art, the technical effect shown in the patent has to be considered in the definition of the objective technical problem."
• "In the Board's view, the technical effect shown in the patent is implicitly considered when the objective technical problem is defined as an alternative. As set out above (point 1.4), it can be expected that the TTS in Example 1 of D1 also maintains its adhesive strength during a certain period of storage. This seems reasonable on its own, given that TTS are not prepared in situ and must retain their adhesive strength for at least a period extending from preparation to commercialisation and application by the final user. Thus, whether the objective technical problem is defined as an alternative or as an alternative which maintains adhesive strength during a period of storage does not change the situation."
  
  
• Commerical products as combination prior art
• "Considering that the essential function of PIB in Example 1 of D1 is to provide good adhesion to skin, the skilled person looking for an alternative would turn to the common PSA polymers used in TTS and select in the first place those providing the highest adhesiveness. Such PSA polymers are disclosed in D12 and, in line with the alternative proposed in paragraph [0097] of D1, are all polyacrylates with the exception of Duro-Tak 87-6908, which is a PIB (last entry of the table in D12). In D12, the most adhesive polymers appear to be non-crosslinked polyacrylates, Duro-Tak 87-2051 clearly being the product with the highest adhesiveness. Therefore, in the light of the teaching in D1 and D12, the skilled person would replace the PIB in Example 1 of D1 with Duro-Tak 87-2051. This appears also to be the non-crosslinked polyacrylate used as the second PSA in the patent examples."
• D12 is "DURO-TAK and GELVA Transdermal Pressure Sensitive Adhesives - Product Selection Guide, Henkel,"
• Whether the skilled person could make "Duro-Tak 87-2051" was not relevant to the decision, entirely in line with G 1/23. 
• "Consequently, the skilled person willing to provide an alternative TTS to the one in Example 1 of D1 would arrive at the subject-matter of claim 1 of auxiliary request 3 in an obvious manner in view of D12."

EPO 

The link to the decision can be found after the jump.

https://www.epo.org/en/boards-of-appeal/decisions/t231408eu1