CABINET CHAILLOT

T1541/19

Inventive step, technical problem, experimental data

T 1541/19
The appeal of the opponent lies against the interlocutory decision of the opposition division concerning maintenance of European Patent number 2 785 803 in amended form.
Claim 1 of the main request of the respondent in appeal read as follows:
"1. A curable film-forming composition for mitigating ice build-up on a substrate, comprising:
(a) a resinous component comprising:
(i) a polyepoxide;
(ii) a polysiloxane; and
(iii) an organooxysilane;
(b) a polyamine and/or an aminosilane;
(c) at least one additional polysiloxane different from the polysiloxane of (ii) above, and
(d) optionally a catalyst; wherein
the polyepoxide (i) comprises a non-aromatic hydrogenated resin which contains more than one glycidyl ether or ester group per molecule."
D1 is the closest prior art for the subject-matter of claim 1 and claim 1 differs from example 3 of D1 in that the polyepoxide is a non-aromatic hydrogenated resin containing more than one glycidyl ether or ester group per molecule (instead of an aromatic polyepoxide: "Epon 862").
According to the respondent, the additional experimental evidence D10 shows that a coating composition according to present claim 1 is characterised by a reduction of the ice adhesion after weathering compared to a coating composition comprising an aromatic polyepoxide. Therefore the objective problem to be solved over D1 should be formulated as the provision of a coating composition providing reduced ice adhesion.
The Board agrees with the appellant that it is not credible that the compositions according to present claim 1 provide any advantage over example 3 of D1 for the following reasons:
(a) According to established case law, if comparative tests are chosen to demonstrate an inventive step on the basis of an improved effect, the nature of the comparison with the closest state of the art must be such that the alleged advantage or effect is convincingly shown to have its origin in the distinguishing feature of the invention compared with the closest state of the art.
In the present case, the respondent provided test report D10 as evidence for an alleged effect related to the presence of a non-aromatic hydrogenated polyepoxide instead of an aromatic polyepoxide.
In order to conclude that any effect shown in D10 has its origin in the nature of the polyepoxide, the Board should be able to rule out the influence of any other aspect of the composition.
While it may be derived from D10 that a hydrogenated resin was replaced by EPON 828 corresponding to an aromatic polyepoxide, D10 does not mention the amount of the various components or the nature of all components present. Therefore, on the basis of D10 alone, the Board and the appellant are not able to evaluate whether the technical effects shown in D10 result from the above distinguishing feature alone or from any other possible difference.
For these reasons, the experimental data presented in D10 are not sufficient to make it credible that there is a technical effect related to the epoxy resin as distinguishing feature.
(b) The appellant further criticised that it would not be credible that the alleged advantage was achieved over the whole scope of claim 1.
According to established case law, if the inventive step of a claimed invention is based on a given technical effect, the latter should, in principle, be achievable over the whole area claimed. Furthermore, if the proprietor of a patent alleges the fact that the claimed invention improves a technical effect, then the burden of proof for that fact rests upon him.
As noted previously, the experimental data submitted in D10 are not considered sufficient to show an effect of the alleged invention.
Present claim 1 covers a large number of embodiments with no limitation as to the amount of the various components. The Board is not convinced that the formulations submitted in the patent are sufficient to make it credible that an alleged technical effect is obtained over the whole scope of claim 1.
For these reasons, the objective problem to be solved must be reformulated as the provision of an alternative curable coating composition that mitigates ice build-up on a substrate.
For the Board, it remains to be evaluated whether it was obvious for a skilled person wishing to provide an alternative to the ice-mitigating composition of example 3 of D1 to replace the aromatic epoxy resin by a non-aromatic hydrogenated epoxy resin as defined in present claim 1.
D1 discloses that the epoxy resin may be selected from a list including the polyglycidyl ether of 2,2-bis(4-hydroxy cyclohexyl) propane corresponding to a non-aromatic hydrogenated epoxide as defined in claim 1. While the said resin may not be the preferred one, it is nevertheless a clear alternative to the aromatic epoxy resin used in example 3 of D1.
It is therefore an obvious option for the skilled person wishing to provide an alternative ice-mitigating coating composition to replace the aromatic epoxide of example 3 of D1 with the polyglycidyl ether of 2,2-bis(4-hydroxy cyclohexyl) propane as suggested by D1. The subject-matter of present claim 1 therefore lacks an inventive step over D1 alone.
The patent is revoked.

 

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