T 1401/14 - Comparative test results

Key points

• The Boar comments on comparative tests results filed by opponent which differed in key features from the examples of the closest prior art D1. "The board agrees with the [proprietor] that the tests carried out by the [opponents] cannot provide any indication as to whether the claimed coating compositions exhibit better or worse properties than the coating compositions of D1. Indeed, the coating composition used in D25 has not been prepared in accordance with example 13 of D1 because, as admitted by [opponent] 01 itself, several components have been replaced for legal, health and/or availability reasons. " 

EPO T 1401/14 - link

1.4.6 According to established jurisprudence, if comparative tests are chosen to demonstrate 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 (see Case Law of the Boards of Appeal of the EPO, 8th Edition 2016, Chapter I.D.10.9).

1.4.7 The board agrees with the [proprietor] that the tests carried out by the [opponents] cannot provide any indication as to whether the claimed coating compositions exhibit better or worse properties than the coating compositions of D1.

Indeed, the coating composition used in D25 has not been prepared in accordance with example 13 of D1 because, as admitted by [opponent] 01 itself, several components have been replaced for legal, health and/or availability reasons. In particular, the replacement of the "acrylic polymer from example 4" of D1 by Degalan**(®) LP 64/12 results in a coating that no longer reproduces the teaching of D1. 

As indicated in point 1.3.2 above, the key feature of the coating composition of D1 is precisely the use of "an epoxy functionalized stabilizer comprising a monomeric unit derived from a glycidyl ester of an alpha,beta unsaturated acid, or an anhydride thereof" (claim 1 of D1, emphasis by the board) and this polymer has been replaced by a quite different polymer, namely Degalan**(®) LP 64/12 (a bead polymer based on methacrylates, see D26, page 1, line 3). It follows that the comparative results in D25 are not suitable to demonstrate the presence or absence of an improvement of the compositions of claim 1 over those of D1.

Similar considerations apply to the comparative experiments in D28/D29. In this case the over-coat comprised, inter alia, "a carboxyl functional (meth)acrylic (co)polymer" (see D28, page 1, 5th paragraph) that again is not a glycidyl ester of an alpha,beta unsaturated acid as required by claim 1 of D1. Consequently, no valid information can be obtained from the comparisons in D28/D29 because they have not been made using coatings like those of D1.

1.4.8 Unlike the experiments in D25 and D28/D29, the coatings used in the [patent proprietor]'s evidence D27 have indeed been made using a copolymer according to claim 1 of D1. They contain an oxirane-functional (meth)acrylic (co)polymer (see table on page 2 of D27, referring back to examples 16 and 17 of the patent in suit and paragraph [0157] of the patent). These experiments thus do support the achievement of superior adhesion than in D1.

Furthermore, in view of the results in the patent, the board concurs with the [patent proprietor] that the corrosion resistance of the claimed coating is excellent.

1.4.9 The [opponents] argued that the examples of the [proprietor] differed in terms of the overall coating thickness and should therefore be disregarded because the improvement observed was due to the different overall thickness of the two-layer coating compared to the one layer coating, rather than to the presence of the polyester under-coat.

The board does not agree. The distinguishing feature of the claimed coatings over those of D1 is the presence of an extra coating (the polyester under-coat) and this further coating needs to have a given thickness. So, the difference in overall thickness in the [proprietor]'s experiments and comparative experiments does not invalidate its finding that the presence of the polyester under-coat leads to excellent corrosion resistance and improves adhesion.

1.4.10 To summarise, in view of the explanations above the board concludes that the experiments in D27 in conjunction with the results in the patent show an excellent corrosion resistance and a significant improvement of the claimed coatings in adhesion over those of D1. This finding is not called into question by the experiments in either D25 or D28/D29, because the comparative coatings used in these documents do not represent the teaching of D1.

1.4.11 The [opponents] argued further that D25 and D28/D29 showed at least that the problem of providing excellent corrosion resistance and superior adhesion had not been credibly solved over the entire scope of the claim because, even if they did not represent the teaching of D1, they at least showed that the use of a polyester under-coat did not necessarily improve the adhesion of the polyvinyl chloride coatings.

The board cannot accept this argument either. Since the experiments in these documents do not represent the teaching of D1, they give no information about whether or not an improvement over D1 can be achieved.

1.4.12 For these reasons, the board is satisfied that the above problem of providing a coating for foodstuff containers which are suitable for storing acidic foodstuffs and beverages, where the coating exhibits excellent corrosion resistance as well as superior adhesion during container fabrication, has been credibly solved over the whole scope claimed.