T 1146/17 (Sealing composition/Bona) 06-03-2019

Main request

1. Sufficiency of disclosure

1.1 The claimed invention relates to a sealing composition, its method of preparation and its use. The sealing composition is defined as comprising components (a), (b), (d) and (f), optionally, also (c) and (e). The respondents' objections, inter alia, concern component (d), defined as silane functional polymer with a molecular weight in the range of 500 to 20000 g/mol.

The application as filed neither specifies whether the molecular weight is, for example, the number or weight average. Nor does it describe the associated measuring method. It is undisputed that different molecular weight definitions and measuring methods may lead to different results.

However, in the present case, this is a question of clarity rather than sufficiency of disclosure. There is no indication that the skilled person would have needed to determine the molecular weight using a specific method to provide the claimed sealing composition. There is also no indication that precise control of the molecular weight would have been necessary to carry out the invention.

The present case therefore differs from T 541/09 cited by respondent 2, where the absence of a measuring method for the weight average molecular weight had the consequence that the claimed process could not be controlled to result in a molecular weight within the required, narrow range.

Moreover, the skilled person is taught in the granted patent that functional polymers, having the required molecular weight, are commercially available from various suppliers (see paragraph [0029] of the patent specification). While the commercial materials are referred to by their trademarks, there is no indication that the reproduction of the invention would have depended on the use of a specific proprietary product. Hence, the question whether the composition or availability of such a proprietary product might change over time is not relevant in the present case.

Thus, the skilled person would have been able to provide component (d).

1.2 The other components defined in claim 1 are also commercial materials and thus would have been readily available to the skilled person (paragraphs [0030], [0033], [0035], [0036], and [0038] of the patent specification).

1.3 Even without a specific working example illustrating the claimed composition, there can be no doubt that the skilled person would have been able to combine, for example, mix, the individual components to provide the claimed composition.

1.4 It was argued with reference to D5P that the invention could not have been carried out across the entire scope of the claim. Specifically, D5P was said to show that the use of methoxysilanes as component (a) was unsuitable for carrying out the invention but that this had not been disclosed on the filing date.

However, the invention as presently claimed is limited to compositions comprising an alkyltriethoxysilane as component (a).

Moreover, D5P was filed in support of arguments relating to inventive step and aims to show beneficial effects, in terms of improved rheological properties, associated with the selection of a specific component (a).

Whether such beneficial effects are obtained may be an issue of inventive step. However, in the present case, it is not relevant for sufficiency of disclosure of the claimed composition. This also applies to whether a certain beneficial effect, or the role of a specific component for such an effect, was foreshadowed in the application as filed. The claimed composition is merely required to be a sealing composition.

The examples of D5P therefore do not constitute any evidence that it may not have been possible to carry out the invention across the entire scope of claim 1. To the contrary, the examples of D5P which relate to a composition of present claim 1, including an alkyltriethoxysilane, rather support the conclusion that the claimed sealing composition could have been provided and that the invention could have been carried out.

1.5 While claim 1 does encompass a huge number of possible compositions, there is consequently no indication or proof that the invention could not have been carried out across the entire scope of the claim and that the skilled person would have needed to conduct a research programme to provide the sealing compositions of claim 1 or would have been faced with other undue burden.

1.6 Respondent 2 has also argued that the burden of proof had shifted to the appellant to show that the invention had been sufficiently disclosed. In this respect, it relied on T 30/15. Additionally, the respondent stressed that D5P constituted a verifiable fact demonstrating lack of sufficiency of disclosure.

T 30/15 deals in the first place with an appellant's obligations to present its complete case in the statement of grounds of appeal and to set out all the reasons why the decision under appeal should be reversed (Article 12(2) RPBA). In the present case, the appellant has complied with these obligations. Even assuming that, nevertheless, the question of burden of proof arose, there were no substantive argument or verifiable fact that would justify its shift to the appellant. Experimental report D5P - as outlined above - does not support the alleged conclusion of lack of sufficiency of disclosure (see point 1.4).

1.7 For the reasons indicated, the skilled person would have been able to provide the sealing compositions according to claim 1 based on the disclosure of the application as filed and common general knowledge.

1.8 There have been no objections specific to the method of claim 6 or the use defined in claim 12. There is no apparent reason why the skilled person would not have been able to carry out the method of claim 6 or use the claimed sealing composition in accordance with claim 12 or the subject-matter defined in the dependent claims.

1.9 Thus, the invention has been sufficiently disclosed (Article 83 EPC).

Reimbursement of the appeal fee

2. Alleged procedural violation

2.1 It is undisputed that the issue of sufficiency of disclosure had been discussed during opposition oral proceedings. What the appellant criticised was that key arguments of the opposition division's reasoning, in its opinion, had not been discussed. These arguments were considered crucial because they had led the opposition division to deviate from their provisional opinion. The appellant therefore sees its right to be heard violated and requests a refund of the appeal fee.

2.2 The appellant's objection concerned specifically the part of the reasoning referring to the vast number of experiments necessary, representing an undue burden in the opposition division's view, as set out on page 11 of the opposition division's decision, last two paragraphs, and page 12, first paragraph.

2.3 The minutes of oral proceedings before the opposition division ("minutes") show that sufficiency of disclosure has been extensively discussed. Whether the skilled person would be faced with an undue burden was addressed (see page 4 of the minutes, lines 24-26). The central aspects in this regard were alleged difficulties linked to the identification of suitable silane functional polymers for use as component (d). Reference was also made to the enormous number of possibilities of this component (see page 4 of the minutes, lines 16-17).

2.4 The criticised part of the decision under appeal refers to the need for over 500,000 experiments and takes into consideration the number of choices linked to the multi-component nature of the composition.

2.5 The board agrees that the criticised part of the decision under appeal thus involves a shift of focus to the multi-component nature of the composition, of which component (d) is merely one component. However, the essence remains the same, namely, that a high number of experiments is necessary, which is considered an undue burden. The difficulties linked to the identification of a suitable component (d) remain an essential element of the reasoning, see item 2 of the decision under appeal. The specific reference to 500,000 experiments merely serves to illustrate the "enormous number of possibilities".

Therefore, no substantial procedural violation has occurred which would justify a reimbursement of the appeal fee.| |

Remittal of the case

3. The appealed decision solely concerned arguments with regard to sufficiency of disclosure. To give the parties the opportunity to present their case before two instances, the board exercises its discretion according to Article 111(1) EPC and remits the case to the opposition division for continuation of the procedure, as requested by the appellant.