T 0773/12 - Product and inventive step

Key points

• Claim 1 of the Second Auxiliary Request in this opposition appeal is for a process for making a dispersion. The description explains that the dispersion can be used advantageously  for making paper coatings. However, this does not contribute to inventive step, according to the Board. The Board seems to require, for inventive step based on the use, that a " specific technical feature of claim 1 [] links its subject-matter exclusively to the use for paper coating" (emphasis added). 
• " The respondent [patent proprietor] argued that the "formulation itself" represents the solution to the problem as defined in [the description]. According to the respondent the intended particular use renders the novel formulation/composition, which is the direct result of the claimed process, allowable. The respondent has stressed the advantages of high solids contents for paper coating. The respondent has however not provided any arguments which specific technical feature of claim 1 of the second auxiliary request links its subject-matter exclusively to the use for paper coating. Also, the board can see no such link. Consequently, the board comes to the conclusion that the subject-matter of claim 1 of the second auxiliary request is not restricted to the technical field of paper coating."

EPO T 0773/12 - link

Inventive step

3.1 The subject-matter of the patent in suit are dispersions of polymer particles having high-solids contents and low high-shear viscosities (paragraph [0001]). When used in paper coatings said formulations exhibit high water retention and good runability during application with a device such as a blade coater (paragraphs [0003]-[0007]). Additional applications, such as paints, impregnants and adhesive compositions are foreseen (paragraph [0023]).

Claim 1 of the second auxiliary request defines a process for the preparation of an aqueous bimodal dispersion of polymer particles having certain particle sizes, i.e. 13 to 50 nm for the smaller particles and 90 to 140 nm for the larger particles, and a certain particle size distribution, weight ratio of the small particles to the large particles of from 10/90 to 40/60, combined with a solids contents of higher than 55 percent. The process includes a step of generating the small particles in the presence of the large particles during the emulsion polymerisation of the desired monomers. The dispersions resulting from the process of claim 1 have high-solids contents and low high-shear viscosities.

3.2 The appellant [opponent] has, inter alia, identified document (4) as closest prior art document. The respondent [patent proprietor] has discussed the disclosure of document (4), but has not commented on its choice as closest prior art document.

Document (4) relates to latex media for coating compositions, such as paper-coating compositions, paint compositions, textile compositions, wood-coating compositions, adhesive compositions, pressure-sensitive adhesive compositions or coating compositions for cement mortar (page 1, lines 2 to 15). It aims at providing latex media having an advantageous compromise between bulk properties and surface properties (page 2, lines 7 to 10). Consequently, document (4) concerns the same technical fields and addresses similar problems as the patent in suit. Thus, the board considers that document (4) represents the closest prior art.

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3.5 The board notes that claim 1 of the second auxiliary request defines a process for the preparation of a dispersion. As can be seen from document (4), bimodal dispersions having the required particle sizes and particle size distributions are suitable for several applications. Document (4) describes several of these applications. Paper coating is listed, but so are several other, different, applications (page 1, lines 2 to 15). The board has addressed the issue of a possible restriction of claim 1 to a certain application in its communication pursuant to Article 15(1) RPBA.

The respondent [patent proprietor] argued that the "formulation itself" represents the solution to the problem as defined in paragraph [0007] (confer letter dated 4 August 2016, page 1, paragraph 5). According to the respondent the intended particular use renders the novel formulation/composition, which is the direct result of the claimed process, allowable. The respondent has stressed the advantages of high solids contents for paper coating. The respondent has however not provided any arguments which specific technical feature of claim 1 of the second auxiliary request links its subject-matter exclusively to the use for paper coating. Also, the board can see no such link. Consequently, the board comes to the conclusion that the subject-matter of claim 1 of the second auxiliary request is not restricted to the technical field of paper coating.

The problem to be solved has thus to be formulated in a general way, taking into account the whole scope of claim 1 and cannot be restricted to a certain application such as paper coating.

3.6 The problem to be solved lies in the provision of a process for the preparation of an aqueous bimodal dispersion of polymer particles which allows for high solids contents while having manageable viscosity properties.

[] The subject-matter of claim 1 of the second auxiliary request is thus obvious in view of the combination of documents (4) and (1).

3.9 The respondent's arguments in support of inventive step do not hold for the following reasons:

The respondent has focused his line of argumentation on the provision of a process to prepare paper coating formulations with high water retention and good runability. However, the subject-matter of claim 1 of the second auxiliary request is not limited to a process [for preparing a product] to be used solely in the technical field of paper coating (see point 3.5 above). Comparative example 3, cited by the respondent for effects linked to particle sizes, is not relevant for the present evaluation, since the closest prior art in the form of document (4) does not differ in respect to the particle sizes.

3.10 Consequently, the second auxiliary request is rejected for lack of inventive step of the subject-matter of claim 1.