T 0123/85 (Incrustation inhibitors) of 23.2.1988

Summary of Facts and Submissions

I. European patent 25 551 was granted on 22 September 1982 on the basis of European patent application 80 105 230.9 filed on 3 September 1980 claiming priority from 13 September 1979. The sole claim read as follows: Use of copolymers which - relative to the weight of the polymers - contain 40 to 90% acrylic or methacrylic acid and 60 to 10% maleic acid as copolymerised units, or their alkali metal or ammonium salts as incrustation inhibitors in detergents.

II. The respondents filed an opposition to the patent, requesting that it be revoked on the grounds set out in Articles 52 to 57 EPC and citing a number of literature references. The appellants then filed a new claim along with further documents. The new claim was worded as follows: Use of copolymers which - relative to the weight of the polymers - contain 40 to 90% acrylic or methacrylic acid and 60 to 10% maleic acid as copolymerised units and which have a K value in their unsaponified state of 10 to 40, or their alkali metal or ammonium salts, as incrustation inhibitors for textile washing processes for phosphate-free or low-phosphate detergents with less than 27 parts by weight of a phosphate in an amount - relative to the dry matter - of 0.5 to 10%. The claim according to the subsidiary request, filed at the same time, differed only in that the claimed ranges for the copolymerised units "acrylic or methacrylic acid and maleic acid" were numerically narrower.

III. In its decision of 23 January 1985, posted on 27 February 1985, the Opposition Division revoked the patent on the basis of Articles 83, 84 and 123(3) EPC; the reasons given were substantially as follows: The appellants had admitted in the oral proceedings on 21 January 1985 that the expression at issue "... low-phosphate detergents with less than 27 parts by weight of a phosphate ..." in the claims according to the main and subsidiary requests should read "... 27% by weight ...". This was not supported by the description or, more precisely, by test detergent A which was used as a reference and only contained 99 parts. This attempt to clarify the position ex post facto therefore - assuming the new form of words was the text henceforth valid - had to be regarded as an infringement of Article 123(3) EPC. The claims were thus not allowable. Furthermore, it was not clear how the K values for the copolymers in their unsaponified state should be determined. Products containing 40 to 90% acrylic or methacrylic acid and 60 to 10% maleic acid as copolymerised units were, it was true, not soluble in methyl ethyl ketone (MEK), the solvent prescribed for the determination. Nor was any particular production method stipulated in the claim. The information in the description, according to which the copolymers could be obtained by reaction of maleic anhydride with acrylic or methacrylic acid and subsequent saponification did not provide an explanation. It would also have to be possible to carry out the invention with a copolymer obtained in any way, i.e. without using maleic anhydride (Article 84 EPC). The Fikentscher method of determining the K value could only be used in the light of the information in the description and the literature it cited, Cellulosechemie 13, 58 ff. from the year 1932. However, viscosity measurements on copolymers of the type in question were not mentioned in that article. In order to obtain the results interpreted by the appellants - concerning the correlation between K values and molecular weights inter alia - it was now clear that further documents would have had to be studied and tests not specifically prescribed would have had to be carried out. That was demanding too much of the public. The subject-matter of the patent had not therefore been disclosed clearly and completely enough for a skilled person to be able to carry it out (Article 83 EPC). The same considerations applied to the claim according to the subsidiary request. The subject-matter of the patent had not been examined for novelty and inventive step because it had not been established what K values and therefore what molecular weights the acrylic maleic acid copolymers actually to be used would have had to have and a comparison of the molecular weights of these products with those of the prior art would not be possible without a degree of doubt.

IV. The unsuccessful patent proprietors and present appellants appealed against this decision in a submission received on 27 April 1985 and paid the prescribed fee. The written Statement of Grounds was received within the prescribed time limit on 29 June 1985. ...

V. ... The claim most recently filed as main request in the oral proceedings was worded as follows: Use of copolymers which - relative to the weight of the polymers - contain 40 to 90% by weight acrylic or methacrylic acid and 60 to 10% by weight maleic acid as copolymerised units, or their alkali metal or ammonium salts, as incrustation inhibitors for textile washing processes for phosphate-free or low-phosphate detergents in an amount - relative to the dry matter - of 0.05 to 10% by weight. ...

Reasons for the Decision

1. The appeal complies with the requirements of Articles 106 to 108 and Rule 64 EPC and is therefore admissible.

2. According to the sole claim (main request) submitted in the oral proceedings on 23 February 1988 the contested patent relates to use of specific copolymers as incrustation inhibitors in detergent formulations. They are intended to replace conventional polyphosphates in respect of this property, the latter's use being increasingly prohibited for reasons of water conservation. Incrustation is understood to mean the deposition of inorganic, salt-like residues on textiles during the washing process.

3. The contested patent was revoked on the grounds that it infringed Articles 123(3), 84 and 83 EPC.

3.1 The claim as it now stands no longer contains the insertion "less than 27 parts by weight of a phosphate" to which the Opposition Division objected, so that revocation under Article 123(3) EPC no longer arises. The existing claim makes it abundantly clear that the claimed incrustation inhibitors are to be used in textile washing processes for low-phosphate or phosphate-free detergents and in a quantity limited in weight. The protection conferred by the claim according to the contested patent has thus been further limited and not extended in compliance with Article 123(3) EPC. As the newly added features shown in bold print were disclosed from the start, the amendments made to do not add subject-matter which extends beyond the content of the application as filed so the requirements of Article 123(2) EPC are also satisfied.

3.1.1 Opponent 02 believes that the appellants cannot delete the feature "less than 27 parts by weight of a phosphate", which they added to the claim in the proceedings at first instance, because they were bound to it "under general principles of procedural law" by having surrendered the appropriate part of the patent. The Board cannot agree with that argument. The European Patent Convention makes no provision for patentees to surrender their patents during opposition proceedings. They can neither surrender the patent as a whole and thus end the proceedings (T 73/84 -

3.2.1, OJ EPO 1985, 241, under point 4; T 186/84 - 3.3.1, OJ EPO 1986, 79) nor surrender part of the patent so as to limit it. A patent may be limited retrospectively solely on the basis of a decision of the Boards of Appeal of the European Patent Office. In opposition proceedings a patentee may only request that his patent be amended; in fact, he himself can file an opposition for this purpose (G 01/84, OJ EPO 1985, 299). Under Article 113(2) EPC the European Patent Office must decide upon the patent in the text submitted or agreed by the patentee. It does not follow from this, though, that the patentee is bound by a request involving revocation or limitation once he has made it. If the patentee himself has filed opposition requesting that his patent be revoked there can be no doubt that he is free to withdraw or amend that request at any time. Exactly the same applies if the opponent is not the patentee but a third party. In requesting that his patent be maintained in a limited form the patentee is merely trying to delimit his patent to meet objections expressed by the European Patent Office or the opponents. However, the patentee does not, by virtue of such limitation, irrevocably surrender subject-matter covered by the patent as granted but not by the request as thus limited. In any case, as explained above, the patentee has no legal means for surrendering part of the patent as granted in this way. A patentee is thus quite entitled to amend his request after it has been made. He can make amendments to subject-matter limited at his request and can thus also reinstate his patent in the form in which it was granted.

3.1.2 However, the Board has one reservation about the admissibility of amendments to the patentee's request in opposition proceedings. Such amendments must not constitute an abuse of procedural law (cf. also T 64/85 - 3.4.1 dated 19 January 1988 under 2.6). The Board believes that there could be cases in which the patentee might be refused the right to abandon his previous request for maintenance in limited form and to reinstate the text of his patent as granted. If a request for amendment constitutes venire contra factum proprium it is inadmissible.

3.1.3 There is no evidence to support such an assumption in the present case. In its communication of 20 September 1984 the Opposition Division requested the appellants (the patentees) to define the term "low-phosphate" to mean a detergent with less than 27 parts by weight of a phosphate. In their response to his communication the appellants filed a new claim by letter dated 13 December 1984 which complied with the Opposition Division's request. In the contested decision the Opposition Division identifies precisely this feature as an inadmissible extension which would lead, inter alia, to revocation of the patent. In these circumstances the appellants are perfectly within their rights in deleting in the appeal proceedings the feature which they inserted at the instance of the Opposition Division but which was then objected to by that Division as an inadmissible extension, and thus to reinstate their patent in the form in which it was granted.

3.1.4 The Board's opinion in the present decision is in line with decision T 64/85 - 3.4.1 of 19 January 1988. In that case the patentee had submitted limited claims of his own accord, without being asked to do so by the Opposition Division, as a concession to the opponent. The submission of the limited text was adjudged as not binding on the patentee but rather as a proposal designed to bring about an amicable accommodation with the opponent at the earliest opportunity. Board 3.4.1 accordingly, like the present Board, concluded that the patentee should be allowed to reinstate his patent in the form as granted despite having earlier submitted a limited text.

3.1.5 Nor could the opponents invoke Decisions J 15/85, OJ EPO 1986, 395 or T 61/85 - 3.3.2 dated 30 September 1987 in support of their case. In Decision J 15/85, given in ex parte proceedings, the filing of claims declared allowable by the Examining Division together with a statement that the other claims should be deleted was judged to be surrender of the deleted claims with the result that a divisional application could not later be filed in respect of their subject-matter. In decision T 61/85 - 3.3.2 surrender was assumed where the applicant had expressly surrendered specific features and deleted the claim and the corresponding parts of the description accordingly. On the basis of these decisions, both of which were given in ex parte proceedings, an applicant may surrender specific parts of his patent application before the patent is granted. This case law is not transposable to the opposition procedure because in the latter it is no longer the application but a granted patent that is at issue, and - as explained above - a granted patent cannot be surrendered in whole or in part by means of a declaration vis-à-vis the European Patent Office.

3.2 The passage relating to the K value for the unsaponified copolymer in the claim forming the basis of the contested decision has been omitted from the new claim so the objection raised under Article 84 EPC can be regarded as having been met. In any case, infringement of Article 84 EPC does not, according to Article 100 EPC, constitute grounds for revoking the patent. ...

5. The discussions concerning the novelty and inventive step of the subject-matter of the contested patent have not yet been concluded....

ORDER

For these reasons, it is decided that:

1. The contested decision is set aside.

2. The case is remitted to the Opposition Division for continuation of the proceedings with the main request submitted in the oral proceedings.