T 0409/10 08-10-2013

1. The appeal is admissible.

Main request:

2. Extension beyond the earlier application, Article 76(1) EPC:

Claim 1 of the main request contains the feature "low molecular weight polyethylene as a rheological additive for making the slurry thixotropic".

2.1 It has not been contested by the appellant that the only reference to the feature "low molecular weight polyethylene" in the parent application EP 96 928 033.8 (published as WO 97/05989) can be found on page 8, line 14-16, and reads:

"An additive which imparts the rheological properties to the slurry is low molecular weight polyethylene Allied Signal AC-9."

2.2 It has been, however, a point of dispute between the parties whether this passage provided a basis for the feature "low molecular weight polyethylene", without any further restriction, as in claim 1 of the main request.

The appellant argued that the skilled person, when reading the above quoted paragraph, would extract the information that any low molecular weight polyethylene was suitable for carrying out the invention. Furthermore, said paragraph mentioned "an additive", not "the additive", which clearly indicated that other possibilities apart from the one explicitly mentioned existed.

The board is, however, of the opinion that the passage on page 8 of the description of the parent application quoted above discloses one suitable additive, namely Allied Signal AC-9, but fails to disclose, in general, every low molecular weight polyethylene. Whether the skilled reader would contemplate, as alleged by the appellant, other low molecular weight polyethylene as alternatives is a matter of obviousness, not of disclosure. The feature "low molecular weight polyethylene" in the main request represents an unallowable generalisation of the embodiment disclosed in the parent application (that is, "low molecular weight polyethylene Allied Signal AC-9"), for which no basis can be found in the parent application.

For this reason, it is concluded that the subject-matter of claim 1 of the main request extends beyond the content of the earlier application as filed, with the consequence that the main request is not allowable.

Auxiliary requests 1 and 2:

3. Clarity, Article 84 EPC:

3.1 The appellant argued that the feature "Allied Signal AC-9" was already present in dependent claim 3 as granted. According to the jurisprudence of the Boards of Appeal the board could not examine this feature with regards to Article 84 EPC, as clarity was not a ground for opposition.

According to the established jurisprudence of the Boards of Appeal, see for example in T 459/09 (not published in the Official Journal of the EPO, see headnote), any amendment that can be qualified as being of a substantial nature would in principle justify an unrestricted exercise of the examination power derivable from Article 101(3) EPC, including the examination of clarity, independently of whether the amendment arises from the incorporation of a feature from the description or from the combination of claims of the granted patent.

In addition, claim 1 does not result, as alleged by the appellant, from the mere combination of the subject-matter of granted claims. The feature "low molecular weight polyethylene Allied Signal AC-9" was present in claim 3 as granted. However, this claim indicated that the slurry was polyethylene Allied Signal AC-9, whereas claim 1 of the auxiliary requests 1 and 2 requires that this component is the rheological additive of the slurry, and not the slurry itself.

Since the feature "low molecular weight polyethylene Allied Signal AC-9" represents a substantial amendment of the subject-matter claimed the board is entitled to examine it with respect to its clarity in order to decide whether, taking into account the amendments made, the patent meets the requirements of the EPC as required by Article 101(3).

3.2 The appellant has argued that the meaning of Allied Signal AC-9 was clear at the date of filing of the patent in suit and any change of composition at a later point of time was irrelevant for the clarity of the claim.

In contrast to other articles of the EPC such as Article 54, Article 84 does not include any reference to any point of time. Hence, the board cannot find this request to satisfy the requirements of Article 84 EPC merely because it is asserted that there was a point in the past at which a term used in the claim would have been clear.

This argument of the appellant is, thus, dismissed.

3.3 Article 84 in connection with Rule 43(1) EPC requires that the claims shall be clear and define the matter for which protection is sought in terms of the technical features of the invention. This requirement ensures that the public is not left in any doubt as to which subject-matter is covered by a particular patent and which is not. It follows from the requirement of legal certainty that a claim cannot be considered clear in the sense of Article 84 EPC if it comprises an unclear technical feature for which no unequivocal generally accepted meaning exists in the relevant art.

Claim 1 of the auxiliary requests 1 and 2 contains the feature "low molecular weight polyethylene Allied Signal AC-9". It is established jurisprudence of the Boards of Appeal that the use of a trade mark in a claim results in a lack of clarity of said claim since it is uncertain whether the meaning of such a trade mark would remain unaltered up to the end of the patent term (see for example T 762/90, point 4.1.1 of the reasons, not published in the OJ EPO). Since, in the present case, there is no evidence on file on the contrary, it is concluded that the blend marketed under the name Allied Signal AC-9 could have changed, or could change, in composition during the patent term, with the consequence that claim 1 of the first and second auxiliary requests are not clear.