T 1474/14 07-03-2018

I. The appeal lies from the interlocutory decision of the opposition division posted on 15 May 2014 according to which European patent No. 1 832 627 as amended according to the documents of the main request (claims as submitted with letter of 22 January 2014 and an amended description thereto) met the requirements of the EPC. Two notices of opposition had been filed requesting revocation of the patent in its entirety.

II. Claim 1 of that request read as follows:

"Use of a curable composition in a seam where the ratio of the displacement width to the average width is 15% or greater, or use of a curable composition as a motor vehicle panel adhesive, wherein for either use said composition comprises:

a polyoxyalkylene polymer (A1) having one or more silicon-containing functional groups capable of cross-linking by forming siloxane bonds in which the one or more silicon-containing functional groups capable of cross-linking by forming siloxane bonds are silicon-containing functional groups each having three or more hydrolyzable groups on one or more silicon atoms thereof; and

a condensate of a tetraalkoxysilane (B)."

Claims 2 to 11 were dependent claims of claim 1.

III. During opposition proceedings, the following documents inter alia were cited:

D1: EP 0 918 062 A1

D4: JP 8-127724 A

D5: JP 2001-72855 A

D9: "Building joint movement monitoring and development of laboratory stimulation rigs" by Hutchinson et al., Durability of Building sealants (1999), edited by A.T. Wolf, pages 99-116

D10: "Elastic bonding - The basic principles of adhesive technology and a guide to its cost-effective use in industry" by Burchardt et al., High-Tech Industrial Adhesives, Technical fundamentals and industrial applications, Verlag moderne Industrie, pages 5-71.

IV. According to the reasons for the decision, the requirements of Article 123(2) EPC were fulfilled. The feature defining that "the ratio of the displacement width to the average width is 15% or greater" was originally present in use claim 12 as granted and accordingly the introduction of this feature into claim 1 as granted could not justify the examination of that claim under Article 84 EPC. Novelty was accepted over D4 and D5, since the compositions described therein were not disclosed to be employed for the specific uses defined in amended claim 1. An inventive step was acknowledged, as there was no incentive to choose a polymer with trifunctional silicon groups and to use such a polymer in D4 for making elastic sealants with good creep and recovery properties.

V. Opponent 2 (appellant) lodged an appeal against that decision and filed a statement of grounds of appeal in which objections under Articles 56 and 84 were maintained against the main request. In spite of a request for oral proceedings at that stage the appellant indicated with letter of 14 December 2017 that they would not attend the oral proceedings.

VI. Opponent 1 (party as of right pursuant to Article 107 EPC, second sentence) indicated with letter of 7 August 2017 that they would not attend the oral proceedings.

VII. Following the Board's communication sent in preparation of the oral proceedings the patent proprietor (respondent) announced with letter of 26 February 2018 that they also would not attend the oral proceedings.

VIII. Oral proceedings were held on 7 March 2018 in the announced absence of the parties (Rule 115(2) EPC and Article 15(3) RPBA).

IX. As far as relevant to the present decision, the appellant's arguments can be summarised as follows:

(a) Having regard to decision T 0459/09, it was justified to examine clarity of the feature "where the ratio of the displacement width to the average width is 15% or greater" present in claim 12 of the patent as granted, because this feature had been incorporated in claim 1, which represented an amendment of a substantial nature to overcome a ground for opposition. As this definition lacked clarity, because it was not specified under which conditions that parameter was to be determined, claim 1 did not comply with the requirements of Article 84 EPC.

(b) D4, which represented a suitable starting point for assessing inventive step, described a curable composition comprising as essential components an organic polymer (A) with at least a reactive silyl group in the molecule and a polymer (B) being a multifunctional hydrolyzable silane compound. According to paragraph [0046] this curable composition could be used as an elastic sealant, because the cured material showed rubber elasticity. Accordingly, this material had to have good creep and recovery properties. A polymer of tetraethoxysilane was disclosed in paragraph [0035] and examples 1 to 5 as preferred polymer (B). The preferred polymer (A) was a polyoxyalkylene polymer with at least one reactive silyl group, which preferably contained two or three alkoxy groups as described in paragraphs [0012], [0013], [0015] and [0016]. The mere selection of one of the preferred alternatives described in D4 for the reactive silyl group did not involve an inventive step. The experimental results submitted by the patent proprietor, which allegedly demonstrated that the use of trimethoxysilyl end groups brought about better recovery properties and creep resistance than end methyldimethoxysilyl groups, were not surprising and constituted for the skilled person a well-known phenomenon. Indeed, a higher number of cross-linking groups would inevitably lead to better recovery properties as was also shown in D5. The skilled person faced with the problem of improving recovery properties and creep resistance would definitely have relied on the systems disclosed in D4 for which the reactive silyl groups had three hydrolysable groups.

(c) The specific use of the curable composition in a seam where the ratio of the displacement width to the average width is 15% or greater could not be taken into consideration for assessing inventive step and therefore could not justify the existence of an inventive step, because the parametric definition of the seam in accordance with claim 1 could not constitute a distinguishing feature having regard to the unclear definition of the ratio of the displacement width to the average width being 15% or greater and to the fact that such values were not untypical as shown in D9. Moreover, the use in construction of seam materials on the basis of silane modified polymers was quite typical and could not justify an inventive step. Also the use of elastic adhesives and seam materials for motor vehicles was common practice as demonstrated by D10 (page 7, lines 1-3).

(d) Accordingly, the subject-matter of claim 1 lacked an inventive step.

X. As far as relevant to the present decision, the respondent's arguments can be summarised as follows:

(a) No clarity issue had been created which did not exist in the patent as granted. Accordingly, there was no basis for allowing a clarity objection into the proceedings. In any event variations of joint width in the construction area, for example due to variations of weather conditions or seismic activity, was a phenomenon well known in the art as shown in D9 and the skilled person was aware of the joint width extension which could be expected for a specific building.

(b) As to inventive step, the key problem addressed by D4, as set out in paragraphs [0003] and [0047], as well as in the working example, was to reduce fouling by surface staining/dust adhesion. Despite the mention of the terms "sealant" and "rubber elasticity" in paragraph [0046] of D4, there was no indication that the material described in D4 should act as a bridge between two heavy substrates. Furthermore, as shown by D9 it was not true that amplitudes of displacement would generally exceed 15%. In fact the ratio of the displacement width to the average width of at least 15% was only observed in certain types of joints and materials. Moreover, the material used in D4 was not limited to polyoxyalkylenes, and contrary to the appellant's allegation, a person skilled in the art had no basis for considering that curable compositions comprising organic polymers with trifunctional silyl groups would show excellent recovery properties and creep resistance. This argument remained a mere assertion in the absence of evidence showing the knowledge of the skilled person in this respect. In addition the prior art cited did not suggest that the use of condensation products of tetraalkoxysilanes would lead to improved recovery properties and creep resistance as demonstrated with examples 8 and 10 of the patent in suit. In D5 the use of tetraalkoxysilanes was merely to improve the storage stability of silyl group-bearing organic polymers. An inventive step was therefore to be acknowledged.

XI. The party as of right did not submit any argument and only requested a decision based on the content of the file.

XII. The appellant requested that the decision under appeal be set aside and the patent be revoked.

XIII. The respondent requested that the appeal be dismissed, or alternatively that the decision under appeal be set aside and the patent be maintained on the basis of any of the first to seventh auxiliary requests, all submitted with letter of 22 January 2014.