T 0658/13 - Sufficiency by product-by-process feature

Key point

• The present decision illustrates how a product-by-process feature may provide for sufficiency of disclosure.

T 0658/13 - link


Summary of Facts and Submissions

XIV. Opponent 1 and opponent 2's arguments, as far as relevant to the present decision, were essentially as follows:

(a) According to the Guidelines for Examination at the EPO, the product-by-process formulation of claim 1 was meaningless. The subject-matter of claim 1 was to be read as being directed to the compositions per se i.e. compositions "obtainable by using" a catalyst system as defined in claim 1, which did not exclude that those compositions could be prepared using a different catalyst system. The only catalyst system which was shown to possibly lead to the combination of features specified in claim 1 was that of paragraph 41 of the patent in suit, which was the same as that used in examples 1-4 of the patent in suit. Considering that the patent in suit did not teach how to produce the compositions of claim 1 when using a different catalyst system than that mentioned in claim 1, the requirements of Art. 83 EPC were not met. In that respect, the argument put forward in respect of other requests dealt with at the oral proceedings and based on example 15 of D5 was also valid.

Reasons for the Decision

1. Sufficiency of disclosure

1.1 In order to meet the requirements of Art. 83 EPC, an invention has to be disclosed in a manner sufficiently clear and complete for it to be carried out by the skilled person, without undue burden, on the basis of the information provided in the patent specification, if needed in combination with the skilled person's common general knowledge. This means in the present case that the skilled person should be able to prepare a bimodal polyethylene polymer composition according to any of claims 1-6 and/or to make a pipe according to claim 7.

1.2 The bimodal polyethylene polymer composition of claim 1 is defined by

- the combination of five parameters as defined in features (a) to (c) as well as in terms of tensile stress at break and PENT failure time under a load of 3.8 MPa (hereinafter "high-stress PENT" which, as indicated in paragraph 57 of the patent specification is a lab-scale test for determining the resistance to slow crack growth);
- the requirement that it comprises less than 1 weight percent of total non-polymeric additives
- the product-by-process feature directed to a catalyst system "wherein the composition is produced using a catalyst composition comprising A and B (...) with sulfated alumina as the activator-support and with tri-isobutylaluminum as the cocatalyst".

1.2.1 During the oral proceedings before the Board it was disputed by the parties whether or not the product-by-process feature identified above was a limiting feature of claim 1 or not.

1.2.2 During the oral proceedings before the Board, the patent proprietor argued that it would not be technically possible to completely eliminate from a polyethylene composition according to claim 1 any trace of the catalyst system that has been used to prepare it, either in the form of the catalyst itself or of its derivated products (should it be e.g. deactivated as argued by opponent 2), even if the composition was to be submitted to a purification step to wash out the catalyst. That argument was not contested by the opponents.

Besides, it is accepted in the art that the catalyst system has an impact on the chemical structure of the polymer composition prepared therewith (e.g. chain length, (co)monomer distribution) and, therefore on the properties of those polymers. In the present case, it is in particular noted that it was not shown that a bimodal polyethylene composition satisfying the five parameters of claim 1, in particular a density higher than 0.952, a TNDR according to feature (c) and a high-stress PENT of higher than 7000 hours could be obtained using a different catalytic system. Therefore, it appears credible that, as argued by the patent proprietor, the use of the catalyst system according to operative claim 1 effectively leads to polyethylene compositions having a very specific structure (e.g. in terms of chain arrangement and monomer distribution) which can only be obtained with the catalyst system defined in claim 1.

1.2.3 The opponents' argument according to which the product-by-process feature was meaningless (i.e. non limiting) is based on section F.IV.15.4.12 of the Guidelines for Examination in the EPO (November 2015), in which it is stated that a claim defining a product in terms of a process is to be construed as a claim to the product as such.

However, it cannot be agreed that said section of the Guidelines implies that a product-by-process formulation as such can only be meaningless. Rather, as is explicitly indicated in the paragraph of the Guidelines cited above related to T 205/83, when novelty of a claim defined using a product-by-process formulation is to be assessed, the question is to be answered whether the product so defined may be distinguished from other known products i.e. it has to be clarified if the "by-process" element of that claim effectively characterises the subject-matter being claimed. 

In the Board's view, this is the case for the polyethylene compositions according to present claim 1 for the reasons indicated in section 1.2.2 above. Besides, in the Board's view, the same conclusion is also to be drawn independently of whether the product-by-process feature of claim 1 reads "produced using a catalyst composition ..." or "obtainable using a catalyst composition ..." (as proposed by opponent 1 during the oral proceedings before the Board) since in both cases the catalyst is mandatorily present in the claimed composition and has to be used in order to obtain a composition meeting the parametric definition set out in claim 1.

Therefore, the opponents' objection based on the argument that the subject-matter of claim 1 encompassed compositions obtained using a different catalyst system than that specified in that claim did not convince.

1.3 [...] Therefore, examples 1 and 4 are held to illustrate the subject-matter of operative claim 1 and to exemplify specific ways to carry out the invention.

1.4 According to EPO case law an objection of insufficient disclosure presupposes that there are serious doubts, substantiated by verifiable facts and the burden of proof is primarily on the opponent(s) (Case Law of the Boards of Appeal of the EPO, 8th. Ed., 2016, II.C.8).

1.4.1 In the present case, the opponents' assertions that it would not be possible to prepare the claimed compositions with either an homopolymer, with other comonomer(s) than 1-hexene or with different amounts thereof are not supported by any evidence. Therefore, the opponents have not discharged their burden of proof and their objection has to be rejected.

1.4.2 During the oral proceedings before the Board and in the first instance proceedings, example 15 of D5 was addressed in respect of sufficiency of disclosure.

Example 15 of D5 deals with the production of bimodal polyethylene compositions using as catalyst system []. Such a catalyst system corresponds to that indicated in paragraph 36 of the patent in suit []. The polyethylene prepared in example 15 of D5 exhibits a PENT under a load of 2.4 MPa of 613 h, which implies that it would have a high-stress PENT (i.e. under a load of 3.8 MPa) outside the range defined in operative claim 1, as agreed by the patent proprietor during the oral proceedings before the Board. However, although the catalyst composition used in said example 15 falls under the general disclosure of the patent as granted, it does not correspond to the catalyst composition now indicated in claim 1 (and corresponding to that disclosed in paragraph 41 of the patent in suit and used in the examples of the patent in suit) because it neither comprises metallocene catalyst A nor tri-isobutylaluminum. Considering the conclusion drawn in section 1.2 above, example 15 of D5 does not constitute evidence that operative claim 1 lacks a sufficient disclosure.

1.5 In the Board's view, the patent proprietor has in the present case overcome the sufficiency objections put forward by the opponents by amending the claims, thereby changing the "invention" referred to in Art. 83 EPC so that it no longer encompasses the insufficiently disclosed previously claimed aspects (Case Law of the Boards of Appeal of the EPO, 8th Ed., 2016, II.C.1).

1.6 For those reasons, the main request meets the requirements of sufficiency of disclosure pursuant to Art. 83 EPC.