CASELAW-EPO - reviews of EPO Boards of Appeal decisions

T 664/20 – Use mentioned in a product claim – "Cascading" claims

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The patent relates to an adhesive composition based on ethylene copolymers, useful for extrusion coating and extrusion lamination on a variety of supports.

Brief outline of the procedure

See the corresponding publication in the present blog.

In this discussion, the question of onus of proof of the proprietor when a use is mentioned in a product claim and the interpretation of cascading claims are touchd upon.

Specific use of a product mentioned in the product claim

The proprietor’s point of view

The proprietor argued that D6=GB-A-991 568 does not disclose the use of the composition obtained in Example 3 in an extrusion-coating process. The indication of use for an extrusion-coating or extrusion-lamination process in claim 1 of the patent as granted confers N on the claimed composition in relation to D6.

The use feature in claim 1 implies a number of implicit features which are not disclosed for the composition of the prior art, in particular in terms of molecular weight, average molecular weight distribution and crystallinity, and that in the absence of disclosure of these properties, it could not be concluded that the composition of Example 3 of D6 is necessarily usable in such a process.

The board’s decision

The failure to disclose the properties of prior art compositions having all the structural features required by the claimed compositions does not prove that the prior art compositions are not suitable for use in an extrusion-coating or extrusion-lamination process, especially since this composition is prepared according to the process of claim 8 of the patent as granted.

In addition, the patent as granted does not contain any information relating to the molecular weight, average molecular weight distribution or crystallinity of the copolymers required by ethylene copolymers for use in an extrusion-coating or extrusion-lamination process. These properties are also not indicated for the copolymers prepared in the patent in suit.

The board concluded that, where a proprietor amends a product claim by stating that the product is intended for a particular use, then the burden of proof rests with him to show that the prior art products cited against novelty and satisfying all the other features of the claim are unfit for the use in question.

The proprietor having the onus of proof, it has not refuted the lack of N based on Example 3 of D6. 

“Cascading” of claims

At stake is claim 1 of AR3.

Claim 1 of AR 3 has been amended to state that the functional copolymer is maleic anhydride.

The limitation to 1% by weight of functional copolymers required by the claims of the patent as granted therefore now applies only to maleic anhydride.

The proprietor’s point of view

The proprietor argued that the catchword of T 999/10 indicates that cascading wording in an open claim, “comprising”, that is, retaining in an amended claim the broad definition of claim 1 and adding, by means of the phrase “and in which…”, an additional restriction, avoids the situation envisaged by decision T 2017/07 where an amendment initially made with the intention of restricting a claim in fact extended the protection conferred by that claim.

Claim 1 of AR3 is drafted in the same way as that discussed in T 999/10, which concluded that there was no extension of the protection conferred by the patent as granted.

The board’s decision

The composition of claim 1 of AR 3, by virtue of being defined as being open to the presence of optional compounds, can thus comprise acrylic acid in a proportion greater than 1% by weight, which was not covered by the claims as granted, because acrylic acid being a functional comonomer, its amount therein is limited to 1%, see T 2017/07; Reasons 2.3 to 2.10.

Therefore, the amendment made in claim 1 of AR 3 extends the protection of the patent beyond that conferred by the patent as granted, cf. Art 123(3).

This restrictive interpretation of the scope of the claim was adopted in T 262/13, Reasons 3.3.1; T 1063/15, Reasons 1.3.2 and T 2215/18, Reasons 4.3.

The board noted that this restrictive interpretation was not followed in T 514/14, Reasons 4.1 to 4.3; T 881/11, Reasons 2.8 and 2; T 52/13, Reasons 4.3, 4.31 and 4.3.2; T 865/13, Reasons 2.4 and T 287/11, Reasons 2.8.2. In the latter decision, it was held that the scope of protection is an objective criterion which must be assessed on the basis of the meaning of the technical features present in the claim and not in the light of the intention of the drafter of the claim, since intention is a subjective criterion.

The Board endorsed the considerations set out in Reasons 2.8.2 of T 287/11 and rejected the argument based on the intentions of the drafter of a claim.

The board also agreed with the considerations in T 514/14, Reasons 2, to the effect that an amendment to a claim must not lead to ambiguity, all the more so if the amendment opens the way to a technically sensible interpretation which, if adopted, renders the claim contestable on the ground that it extends the scope of protection conferred by the patent as granted.

A so-called “cascading” formulation of features is likely to lead to ambiguity of the claim. Where a claim is defined as including a generic class of compounds present in a weight range and the claim is amended ‘cascade’ to indicate that the generic class is a specific compound, then the weight range applies to that specific compound, and no longer to the generic class


Use mentioned in a product claim

In a product claim the mention of a use, “for”, is prima facie not limiting, unless it necessarily implies specific features/proprieties. A claim to a patch “for” treating wrinkles is substantially different from a patch “for” alleviationg pain.

If the known product is in a form in which it is in fact suitable for the stated use, though it has never been described for that use, it deprives the claim of N, see also Guidelines F-IV, 4.13. The proprietor claiming N by virtue of the use, had thus clearly the onus to proof that the composition of example 3 of D6 was unsuitable for the envisaged use. The proprietor failed to provide this proof.

“Cascading” claims

In the current wording, the interpretation that the 1% rate applies to all comonomers would require giving two different meanings to the term “functional comonomer”, which would refer to maleic anyhydride, except as regards the quantitative aspect. This is the ambiguity which has been raised by the board.

As a claim has to be clear on its own, such an ambiguity is to be avoided, but this should not be left to possible intentions of the drafter of the claim.

In view of the divergent case law, it could be useful if, eventually, the EBA would clarify the situation.

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