T 1154/16 - The broader, general, field of polyurethanes in dynamic mechanical applications

Key points

• In this opposition appeal, one of the questions under inventive step is whether the skilled person would have consulted the secondary documents D9 and D19.
• “The patent proprietor has argued that the skilled person would not consider documents D9 or D19 as they do not relate to the same technical field as the contested patent, i.e. shoe press belts for papermaking and do not address the same technical problem.”
• “The opponent has argued that the skilled person would have been aware of documents D9 and D19 and would consider their disclosure as they form part of the state of the art in a non-specific general field [...]”
• “ The Board finds that the disclosures of D9 and D19 in the present case cannot be considered to be in a neighbouring field to that of shoe press belts for papermaking, but that they do form part of a broader, general field, relating to the general use of polyurethanes in dynamic mechanical applications solving similar problems to the current case. Therefore the skilled person would consider the disclosure of both documents.”
• The Board considers the claims to be inventive even in view of D9 and D19.

EPO T 1154/16 -  link

3.2 Objective technical problem

3.2.1 A shoe press belt for papermaking is known from document D8 which by common consent represents the closest prior art.

3.2.2 Both parties agree that the subject-matter of claim 1 differs from the known belt of D8 in that the urethane prepolymer (A) is obtained by reacting an isocyanate compound (a) comprising 55 to 100 molar % of a p-phenylene-diisocyanate (PPDI) compound.

3.2.3 The objective technical problem was regarded by the opposition division in the contested decision (see page 12) as being to provide an improved shoe press belt which has good mechanical properties in crack resistance, flexural fatigue resistance and wear resistance.

The patent proprietor has argued (statement of grounds of appeal, page 6, third paragraph) that the objective technical problem should be reformulated as providing flexural resistance (in the sense of resistance to crack development and growth under repetitive flexing) whilst maintaining or improving hardness values of press shoe belts.

In the opinion of the opponent, however, the maintenance or improvement of the hardness of the polyurethane layer does not form part of the objective technical problem as it is a mere bonus effect.

3.2.4 The established case law (Case Law of the Boards of Appeal, supra, I.D.4.3.2) indicates that an objective definition of the technical problem to be solved should normally start from the problem described in the contested patent, unless the problem has not been solved. In the present case the opposition division used the problem as defined in paragraph [0012] of the contested patent. They reasoned that considering the examples given in the patent and the additional examples provided by the proprietor in document D15 the invention involved an advantageous technical effect related to the technical problem of providing a shoe press belt having improved crack resistance, flexural fatigue resistance and wear resistance over the whole range of claim 1.

The Board sees no reason to depart from the technical problem formulated in the contested patent.

3.3 Technical fields

The patent proprietor has argued that the skilled person would not consider documents D9 or D19 as they do not relate to the same technical field as the contested patent, i.e. shoe press belts for papermaking and do not address the same technical problem.

The opponent has argued that the skilled person would have been aware of documents D9 and D19 and would consider their disclosure as they form part of the state of the art in a non-specific general field and show general improvements in dynamic properties related to the use of a PPDI/PTMG/BDO polyurethane (see submission of 9 July 2020, points 2.1 and 2.2, pages 5-9).

The patent proprietor responded (submission of 7 August 2020, points 2.1 and 2.2, pages 5-7) by arguing that technical fields cannot be neighbouring if they relate to substantially different purposes and applications, and that documents D9 and D19 relate to different technical problems than the objective technical problem of the patent.

The Board finds that the disclosures of D9 and D19 in the present case cannot be considered to be in a neighbouring field to that of shoe press belts for papermaking, but that they do form part of a broader, general field, relating to the general use of polyurethanes in dynamic mechanical applications solving similar problems to the current case. Therefore the skilled person would consider the disclosure of both documents.

[...]

Therefore, even if the skilled person were to be prompted by the disclosure of D9 and D19 to replace TDI/MDI urethane prepolymers in the shoe press belt of D8 with PPDI prepolymers, D9 and D19 clearly teach the use of PPDI prepolymers in combination with BDO as the curing agent. The skilled person, when starting from the teaching of D8, with the desire to improve crack resistance, and without knowledge of the invention, would see no reason to replace the curing agent which D8 teaches as being precisely the component which improves crack inhibition.

This already suffices to acknowledge that the claimed subject-matter involves an inventive step.

3.5 The patent proprietor has therefore convincingly shown that the contested decision was incorrect and that the patent may be maintained as granted.

Order

For these reasons it is decided that:

1. The appeal of the opponent is dismissed.

2. The decision under appeal is set aside.

3. The patent is maintained as granted.