T 0639/92 (Detergent Composition/PROCTER & GAMBLE) 28-02-1996

1. The appeal is admissible.

2. The Board is satisfied that the sets of claims according to the main and the auxiliary request meet the requirements of Article 123(2) and (3) EPC. Since the appeal had to be dismissed for another reason, it is not necessary to give reasons for this finding. Nevertheless, the Board observes that the deletion of one of two definitions of "n" which were both disclosed in the application as filed does not infringe Article 123(2) EPC. Respondents I did not dispute that the definition now retained was that already used in Claim 1 as filed and in the part of the description reciting the wording of that claim (see the description as filed, from page 2, line 22, to page 3, line 2, from the bottom). The deletion from the description of the alternative definition was thus no more than the removal of an inconsistency between the claims and the description.

3. Main request

3.1. The clarity of Claim 1 as amended during oral proceedings has not been disputed by the Respondents. In particular, Respondents I did not maintain their objection to the reliability of the "turbidity method" described in the patent in suit (see page 3, lines 49 to 54. of the description). However, it was in dispute whether the description disclosed a polymer satisfying the definition of component (b)(i) of the claimed detergent composition, because polymer "PC4" (described on page 10, lines 34 and 35, of the description of the patent in suit), while having the required magnesium building capacity, was said to have a number of acrylic acid derived units (corresponding to the number "n" in formula I) below that required by Claim 1. Although Respondents I were prepared to accept the Appellant's submission that the average molecular weight of about 15 500 given for this product on page 10 of the description of the patent in suit related to the polymer in the acid form, the Board has doubts about whether this interpretation of the disclosure of the patent in suit is correct. The reason for this is that in formula I the number "n" defines the number of the acrylic acid derived units wherein M may be an alcali metal. The value of "n" must be calculated from the weight average molecular weight, which should relate to the indicated product, hence the sodium salt in the case of the products "PC1" to "PC5" mentioned on page 10 of the description of the patent in suit. On that basis, it is rather doubtful whether the present Claim 1, the subject-matter of which is inter alia defined by the magnesium building capacity, would be sufficiently supported by the description of the patent in suit, in the absence of any indication as to which available products are meant by this definition. However, similar considerations apply in respect of the requirement of sufficiency of disclosure (see also decision T 409/91, OJ EPO 1994, 653, points 3.3 to 3.5 of the reasons). Since the decision under appeal was also based on the finding that the compositions defined by Claim 1 underlying this decision were not sufficiently disclosed, the Board need not take a decision on the issue of sufficient support by the description of Claim 1 under Article 84 EPC. It has decided to proceed, instead, to the examination of the issue of sufficiency of disclosure.

3.2. In the Boards judgment, the requirements of Article 83 or 100(b) EPC are only met if the invention as defined in the amended Claim 1 can be performed by a person skilled in the art in the whole area claimed without undue burden, using common general knowledge and having regard to the examples and the further information given in the patent in suit.

Contrary to the view expressed by the Appellant, the Respondents disputed that it was possible to obtain a polycarboxylate polymer having the structure defined by formula I in Claim 1 and a magnesium building capacity as defined in that claim without undue burden, and argued that, in these circumstances, the claimed invention could not be carried out.

In respect of the disclosure in the application as filed or the description of the patent in suit and common general knowledge, the following facts were established during the oral proceedings:

3.2.1. The Appellant did not dispute that, after Respondents I had failed to obtain a sample of a polymer of formula I, in which Y is a maleic acid derived unit, p is from 0.1 to 1.9 and n averages from 120 to 400, having the required magnesium building capacity, he was unable to provide them with a sample of such a product. The Appellant further admitted during oral proceedings that the magnesium building capacity was not a usual parameter for characterising polycarboxylate polymers which was normally determined and made publicly available for commercial products of this type. In addition, the Appellant did not dispute that the application as filed or the patent in suit failed to provide a reliable method for obtaining suitable products, and admitted that there was no explicit indication of the magnesium building capacity of the polymers used in the examples.

Therefore, the sole specific information relating to the required magnesium building capacity of the polycarboxylate polymers made available by the application as filed or the patent in suit concerned the method for determining it.

3.2.2. During the opposition proceedings, the Appellant has submitted, in Appendix I to the letter received on 15. November 1989, the magnesium building capacities (determined by him according to the method disclosed in the description of the patent in suit, page 3, lines 47 to 54) of some commercially available polymers of formula I, wherein X is CH2, Y is a comonomer or comonomer mixture, R1 and R2 are bleach and alkali-stable polymer-end groups, R3 is H or C1-4 alkyl, M is H, alkali metal, alkaline earth metal, ammonium or substituted ammonium, p is from 0 to 2, and n is at least 10. Among other products, this list contains the maleic/acrylic copolymer "Alcosperse 175", having a magnesium building capacity of 2,75, i.e. outside the range specified in Claim 1. The Appellant did not dispute the Respondents' submission that this product is a product of formula I, in which Y is a maleic acid derived unit, p is 0.43 and n is 208 (see Annex 2 to the minutes of the oral proceedings before the Opposition Division).

It follows that there is no correlation between the above structural parameters and the magnesium building capacity. This was not disputed by the Appellant. Moreover, having regard to the uncertainty as to whether the sole product specifically disclosed in the application as filed and the patent in suit that turned out to have the required magnesium building capacity - according to the Appellant's submission during the opposition proceedings -, meets the structural requirements of Claim 1, it is even questionable whether one single product had been disclosed which would satisfy all requirements set out in Claim 1.

3.2.3. The Appellant has not provided any evidence in support of his allegation that the number of products comprised by this definition, which would have to be tested for their magnesium building capacity, was in fact small. The Respondents' submission that the above definition of component (b)(i) comprises a host of products which may or may not possess the required magnesium building capacity being prima facie credible, having regard to the range of n-values and monomer ratios to be considered (see point VI above), the Board concludes that the number of possible components b)(i) to be synthesised and tested is indeed very large.

3.3. In these circumstances, the Board cannot accept the Appellant's submission that it would not amount to an undue burden for a person skilled in the art to synthesise all products of formula I in which Y is a maleic acid derived unit, p is from 0.1 to 1.9 and n averages from 120 to 400, and to determine their magnesium building capacity. On the contrary, in the absence of any indication of a suitable product in the description of the patent in suit (see point 3.2.1 above) and without any guidance as to how to synthesise such a product with an adequate statistical rate of success, the Board comes to the conviction that it would require an extended experimental search with quite an uncertain expectation of success to find suitable products of formula I in which Y is a maleic acid derived unit, p is from 0.1 to 1.9 and n averages from 120 to 400, and which have a magnesium building capacity of at least 3.0 moles/kg at both 25 C and 90 C (see decision T 226/85, OJ EPO 1988, 336, reasons points 7 and 8; and decision T 435/91, OJ EPO 1995, 188, reasons point 3.2).

On the basis of the available evidence, the Board is thus not satisfied that the patent in suit discloses the subject-matter of the present Claim 1 in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art, as required by Article 83 EPC.

3.4. For this reason, the main request must fail.

4. Auxiliary request

4.1. Claim 1 of the auxiliary request differs from Claim 1 of the main request only by a more restricted definition of the polymer component b(i). However, this definition still comprises the products of formula I in which Y is a maleic acid derived unit, p is from 0.1 to 1.9 and n averages from 120 to 400, and which have a magnesium building capacity of at least 3.0 moles/kg at both 25 C and 90 C. Therefore, the facts established under point 3.2 above in respect of the compositions defined in Claim 1 of the main request apply equally here, although the group of compositions defined by Claim 1 of the auxiliary request is certainly narrower than that defined in Claim 1 of the main request.

4.2. Consequently, the auxiliary request must fail for substantially the same reasons as those set out, under point 3.3 above, in respect of Claim 1 of the main request.