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EPO - Arkema France v/ Evonik Römh GmbH

Date de la décision


N° de la décision

T2553/12 – 3.3.03

Type de jurisprudence



EPO - Board of Appeal


Arkema France v/ Evonik Römh GmbH

The patentee, Arkema France, was represented by Véronique CREST, European patent attorney. The decision of the Board of Appeal is favorable to the patentee and maintains the patent as amended, according to the main request.

The opposition was directed against the European patent EP 1 910 464 in the name of Arkema France on the basis of inadmissible extension of the subject-matter, lack of sufficiency, lack of novelty and lack of inventive step.

The invention relates to a acrylic multilayer composition comprising from the outside in :

  • - an outer layer comprising an acrylic polymer matrix and from 5 to 60% by weight of a hard-core core/shell impact modifier, having at least three layers, having an average particle size of less than 225 nm , wherein said hard-core has a Tg of greater than 0°C, and
  • - an inner layer comprising a thermoplastic acrylic polymer matrix and from 4 to 60% by weight of an impact modifier having an average particle size greater than or equal to 225 nm.

The object of the invention is to provide a material having good weather resistance, good chemical resistance, good abrasion resistance and especially gloss retention after thermoforming.

According to a preferred embodiment, the acrylic multilayer composition may be used for example for shower walls. A thermoforming step is needed to give a particular shape to the product. One of the aims of the invention is to retain the gloss properties of the material after thermoforming.

In its decision, the Opposition Division maintained the patent according to the main request. The opponent lodged an appeal against that decision.

The reasons for the decision relative to sufficiency are interesting. Indeed, the patent had several weaknesses relative to sufficiency.

First, the first attack of the opponent concerns the size of the impact modifiers. The opponent asked whether this particle size means the size of the particle as a reagent, that is, before it is incorporated into the polymer matrix, or whether it means the size of the particle, once it is incorporated into the matrix. However, according to the examples of the patent, the last layer of the impact modifier could be of the same material as the material of the matrix, the last layer of the impact modifier is thus melt into the matrix. This leads to an ambiguity on the claimed value of the size of the impact modifier.

It should be noted that the Opposition Division considered this value of the size of the impact modifiers as a matter of clarity, and invoking the ambiguity of the boundary defining the parameter.

The Board of Appeal did not consider the definition of the parameters from the point of view of clarity but under the ground of sufficiency.
In addition, the Board notes that the claim also includes characteristics of the impact modifier particles as well as the Tg of the hard-core of the impact modifier and the amount of particles.

The Board recognizes the difficulties that the person skilled in the art will have in implementing the claimed object. According to the Board, a person skilled in the art will immediately recognize the lack of practicality and the difficulties associated with any measurement of the size of the impact modifier when embedded in the film. According to the Board, the parameters of claim 1 cannot be understood to define results of measurements carried out on the multilayer composition, but rather simply the proportions of the ingredients and the nature of the impact modifiers to be employed for preparing the multilayer product .

Furthermore, the Board notes that impact modifiers are conventional ingredients in the art at the date of filing of the patent and that one skilled in the art knows perfectly how to prepare the claimed multilayer composition, as he knows the blending techniques for preparing the various mixtures of impact modifiers and matrix polymer.

Therefore, the Board concluded that the claimed invention was sufficiently described. In this decision, those skilled in the art are perfectly familiar with the products to be used and recognize that the claimed parameters were those of the reagents and not those of the final product.

Moreover, concerning the inventive step, the invention was considered inventive, as none of the cited documents states the problem of gloss retention after thermoforming.