T 1375/06 06-05-2008

I. Appellant I (patentee) and appellants II and III (opponents 01 and 02) lodged appeals against the interlocutory decision of the Opposition Division maintaining European patent No. 1 022 115 in amended form.

II. The Opposition Division did not admit a main request and was of the opinion that the subject-matter of claim 1 of auxiliary requests 1 to 6 did not involve an inventive step. The patent in suit was maintained in accordance with auxiliary request 7 of appellant I.

III. Oral Proceedings were held before the Board of Appeal on 6 May 2008.

IV. Appellant I requested that the decision under appeal be set aside and the patent in suit be maintained on the basis of the following documents:

(i) Main request: claims 1 to 14 filed as "Requête principale" on 31 August 2007; or

(ii) Auxiliary request: claims 1 to 5 filed as "Requête subsidiaire 1" during the oral proceedings.

Appellants II and III requested that the decision under appeal be set aside and that the European Patent No. 1 022 115 be revoked.

V. Claims 1, 7 and 11 of the main request read as follows:

"1. An extruded polymeric article comprising a polymeric matrix and polymeric particles which are substantially spherical, highly crosslinked, have a mean particle size of 25-55 micrometers and have a particle size distribution between 10-110 micrometers, wherein the article has a frosted and surface textured finish,

wherein the frosted appearance is achieved through the mismatch of the refractive indices of the polymeric particles and polymeric matrix by greater than 0.02, and

wherein the polymer used as the polymeric matrix is an acrylic polymer and the polymeric particles comprise 10-50% styrene, 90-50% methyl methacrylate and 0.1-2.5% crosslinking agent."

"7. An extrudable resin comprising

a) 20-90% polymethyl methacrylate based matrix;

b) 5-50% modifiers; and

c) 5-30% highly crosslinked spherical beads comprising

10-50% styrene;

90-50% methyl methacrylate; and

0.1-2.5% crosslinking agent,

wherein the beads have a mean particle size of 25-55 micrometers, and a particle size distribution of between 10-110 micrometers,

wherein there is a mismatch of refractive indices of the highly crosslinked spherical beads and polymethyl methacrylate based matrix by greater than 0.02."

"11. An extrudable resin comprising

a) 70-85% polymethyl methacrylate based matrix; and

b) 15-30% highly crosslinked spherical beads comprising

15-35% styrene;

65-85% methyl methacrylate; and

0.5-1.5% allyl methacrylate,

wherein the beads have a mean particle size of 25-55 micrometers, and a particle size distribution of between 10-110 micrometers, wherein there is a mismatch of refractive indices of the highly crosslinked spherical beads and polymethyl methacrylate based matrix by greater than 0.02."

Claims 1 and 5 of the auxiliary request differ from claims 7 and 11 respectively of the main request in that the term "weight" is introduced before "mean particle size".

VI. The following documents are referred to in the present decision:

D53: Reworking of Example 2A of the patent in suit

D53a: Affidavit of Dr. Schwarz-Barac, concerning reworking of Example 2A

D53b: Affidavit of Mr. Schnabel, concerning reworking of Example 2A

D54: Particle size distribution of sample 16405/50

D55: Reworking of Example 2B of the patent in suit

D55a: Affidavit of Dr. Schwarz-Barac, concerning reworking of Example 2B

D55b: Affidavit of Mr. Schnabel, concerning reworking of Example 2B

D56: Report No. A060026403

VII. The arguments of appellant I in the written and oral proceedings can be summarised as follows:

The invention as defined in claim 1 of the main request can be carried out by the person skilled in the art in the light of the description. In particular, it is possible to produce particles having the specified mean particle size of 25-55 micrometers and the specified particle size distribution of between 10-110 micrometers.

As indicated in paragraph [0030] of the patent in suit, the mean particle size is a weight mean. The particle size distribution refers to a substantially Gaussian distribution of the particles between 10-110 micrometers. It is possible that a small amount of the particles falls outside the specified range.

Such a distribution is obtained when carrying out the Examples of the patent in suit. In the event that a different distribution is obtained, it would be possible to separate out particles having the desired particle size.

VIII. The arguments of appellants II and III in the written and oral proceedings can be summarised as follows:

The patent in suit does not provide a disclosure which would enable the person skilled in the art to carry out the invention as defined in claim 1 of the main request.

In particular, no process is disclosed which would result in the production of particles having the specified mean particle size of 25-55 micrometers and the specified particle size distribution of between 10-110 micrometers.

When producing particles by an emulsion process, as suggested in paragraph [0022] of the patent in suit, it is impossible to exclude the formation of particles falling outside the specified particle size distribution. As stated at paragraph [0033] of the patent in suit, "agitation speed, and composition and level of the suspending agent are critical factors in determining the particle size distribution". There is, however, no indication as to what parameters should be used in the manufacture of the particles. As stated at page 5, line 1, "the typical particle size from suspension is about 10-1000 micrometers".

The process of Example 2A results in a weight mean of 20-30 micrometers, and that of Example 2B results in a weight mean of 35-60 micrometers. These examples thus fall outside the range specified in claim 1.

Documents D53 to 56 demonstrate that reworking of Examples 2A and 2B of the patent in suit gives rise to a product having a mean particle size greater than that specified in claim 1 and a particle size distribution falling outside the specified range.