T 0016/87 (Catalyst) of 24.7.1990

Summary of Facts and Submissions

I. The respondents are the proprietors of European patent No. 0 027 069 filed on 18 September 1980 (application No. 80 401 328.2) and claiming the priority of French patent application No. 7 924 675 of 4 October 1979.

II. The appellants gave notice of opposition to that patent and asked that it be revoked in its entirety on the grounds that its subject-matter was not new having regard to document DE-A-2 928 249 (D1), which was published between the priority date and the date of the European filing, and did not involve the required inventive step having regard, in particular, to documents DE-A-2 747 373 (D2) and DE-A-2 637 198 (D8).

III. In an interlocutory decision under Article 106(3) EPC, the Opposition Division noted that none of the grounds for opposition referred to in Article 100 EPC prejudiced the maintenance of the patent, as amended on the basis of the documents cited in the communication pursuant to Rule 58(4) EPC issued on 10 January 1986.

IV. The appellants appealed against that decision.

V. At the conclusion of oral proceedings, the appellants (opponents) asked that the contested decision be set aside and the patent revoked. The respondents (patent proprietors), for their part, requested that the appeal be rejected and the patent maintained on the basis of Claims 1 to 12, submitted during the oral proceedings as their main request, and an amended description as indicated in the communication pursuant to Rule 58(4) EPC issued by the Opposition Division on 10 January 1986 (main request).

Claims 1 and 12, the only independent claims in this set of claims, read as follows:

"1. Catalyst for the treatment of the exhaust gases from internal combustion engines, characterised in that it comprises: a support based on a refractory oxide and an active phase consisting of cerium, iron, at least one metal chosen from among platinum and palladium and at least one metal chosen from among iridium and rhodium, the content of platinum and/or palladium being between 0.04 and 0.5% by weight relative to the support, the content of iridium and/or rhodium being between 0.002 and 0.1% by weight relative to the support, the ratio of the weight of platinum and/or palladium to the weight of iridium and/or rhodium being between 4 and 40 and preferably between 7 and 20, the content of iron being between 0.1 and 3.5% by weight relative to the support, and the content of cerium being between 0.3 and 4.4% by weight relative to the support.

12. Process for the treatment of the exhaust gases from internal combustion engines, which, in particular, makes it possible to eliminate the greater part of the carbon monoxide, of the unburnt hydrocarbons and of the nitrogen oxides present in these gases, characterised in that the catalyst according to any one of Claims 1 to 11 is used."

Claims 2 to 11 are dependent on independent Claim 1. The respondents requested in the alternative that the patent be maintained on the basis of Claims 1 to 10 submitted during the oral proceedings as their subsidiary request, and on the basis of a description to be amended (alternative request). Claim 1 of the subsidiary request differs from Claim 1 of the main request in that it is limited to a support based on alumina, heat-stabilised by introducing into it an alkaline-earth metal, silica and/or a trivalent rare earth.

VI. The arguments advanced by the appellants in support of their request for revocation of the patent can be summarised as follows:

(a) In the first place, the patent does not sufficiently disclose the invention to which it relates. In particular, it gives no examples of the active-phase composition of a catalyst containing the noble metals iridium or palladium and, as regards the other elements, the examples given in no way cover the full range of compositions claimed. As a result, it is not certain whether the alleged invention can be carried out throughout the field covered by the claims.

(b) The subject-matter of Claim 1 according to the respondents' main request is not new having regard to document D1, which discloses examples of a catalyst with the claimed composition. That document, published on 24 January 1980, is prejudicial to the validity of the contested patent, which has a later filing date and cannot be accorded the claimed priority date of 4 October 1979 since the French application whose priority is claimed did not limit current Claim 1, according to which the ratio of the weight of platinum and/or palladium to the weight of iridium and/or rhodium is between 4 and 40 and preferably between 7 and 20.

In this connection, it would not be fair to allow an applicant to introduce - after an application's priority date - arbitrary limitations not supported by that application to avoid it being anticipated by a prior art document (in the present case, document D8), whilst retaining the priority date. (c) (...)

VII. This viewpoint was contested by the respondents, who argued, inter alia, as follows:

(a) The invention satisfies the disclosure requirement laid down in Article 83 EPC because, firstly, a person skilled in the art is perfectly capable of reproducing a catalyst corresponding to the definition in Claim 1 using the full range of compositions claimed, even if the description part of the patent discloses only a certain number of specific examples. Secondly, the object of the invention, which is to improve the behaviour of multifunctional catalysts at low temperature, is achieved across the full range claimed, even if to a greater extent for the specific examples described.

(b) Whilst it is true that the ratio of the weight of platinum and/or palladium to the weight of iridium and/or rhodium defined in Claim 1 did not appear in the priority document, that feature was included in the claim simply to delimit it better from a prior national right. The patentability of Claim 1 is not, however, based on that additional feature but derives from the other features of the claim. Since these other features were all disclosed in the priority document, they must benefit from the priority claimed at the time of filing and should not therefore be considered in the light of document D1.

(c) (...)

Reasons for the Decision

1. (...)

2. (...)

3. (...)

4. Sufficient disclosure of the invention (Article 100(b) EPC) The appellants voiced doubts about whether the invention was disclosed sufficiently in the description part of the patent in suit since no examples had been given of the active-phase composition of a catalyst containing iridium or palladium and the examples that were given did not cover the full range of compositions claimed. The Board would point out in this connection that Rule 27(1)(f) EPC requires only one way of carrying out the invention, using examples where appropriate, to be described in detail. (See, for example, Decision T 87/86 dated 18 May 1988, not published in the EPO Official Journal). In the present case, several examples were given and the appellants themselves carried out comparative tests, which shows they had no difficulty reproducing the subject-matter of the invention on the basis of what was disclosed in the description, i.e. the invention was disclosed sufficiently for it to be carried out by the skilled person.

What the appellants are in fact objecting to is that the respondents had not proved that the claimed catalyst was active for all combinations and percentages mentioned in Claim 1. However, as pointed out above, the patent proprietor is not required to furnish such proof. It is enough for it to appear plausible to the skilled person - given the described method of carrying out the invention and any examples furnished - that the invention can be carried out with the combinations mentioned and across the range of combinations given. Under Rule 55(c) EPC, it is for the opponent who invokes the partial invalidity of a patent on the ground that the invention cannot be carried out for certain compositions or ranges of composition to indicate the facts, evidence and arguments presented in support of that ground; in other words, he must, for example, furnish the results of tests proving that the catalyst is not active. The appellants have not done this in the present case: they have merely expressed doubts. Under these circumstances, the Board is unable to accept this ground for revoking the patent.

5. Validity of the priority claimed (Article 88(3) EPC) The appellants argued that the priority of French patent application No. 7 924 675 had not been validly claimed, because Claim 1 of the European patent contained a feature relating to the ratio of the weight of platinum and/or palladium to the weight of iridium and/or rhodium not disclosed in the French patent application.

Article 88(3) EPC states that the right of priority covers only those elements of the European patent application which are included in the application whose priority is claimed. It therefore follows, in the present case, that the priority of the French application was validly claimed for all the features of Claim 1 other than the added feature, considered separately. That added feature, however, does not represent an essential element of the subject-matter of Claim 1 which would have altered its nature in such a way that the invention was new compared with that to which the French application relates. Instead, it represents simply a voluntary limitation of the scope of that claim (cf. Decision T 73/88 - 3.3.1 dated 7 November 1989, point 2 of the Reasons, not published in the EPO Official Journal). Under these circumstances, the Board is unable to agree with the appellants' arguments on this point and consequently considers that document D1, published after the priority date and invoked by the appellants against all the features of the contested patent's Claim 1, does not form part of the state of the art as defined in Article 54 EPC and does not therefore need to be considered.

6. Interpretation of Claim 1 (Article 69 EPC) In the course of the appeal proceedings the correct interpretation to be given to Claim 1 and in particular to the feature relating to the claimed catalyst's cerium content was discussed on a number of occasions. According to the respondents, the quantity of cerium indicated in Claim 1 related only to the cerium that actually played an active part in the conversion of exhaust gases and did not include any small amounts of cerium introduced into the support to improve its thermal stability (point VII(c) above, not published). The appellants, on the other hand, claimed that thermal stabilisation and conversion of the cerium were indissociable, so that the cerium content specified in Claim 1 also covered quantities of cerium introduced primarily to improve the thermal stability of the support's surface (point VI(c) above, not published).

The provision in Article 69(1) EPC stipulating that the description and drawings (if any) be used to interpret the claims also applies during opposition proceedings when an objective assessment of the content of a claim has to be made to judge whether its subject-matter is novel and not obvious. The Board considers that an examination of the wording of Claim 1 reveals a clear distinction between the support based on a refractory oxide, on the one hand, and the active phase on the other, the cerium content being included only in the active phase. Dependent Claim 8 and the description (page 3, line 64, to page 4, line 2) show that the support itself could have been treated in such a way as to give it good thermal stability with the passage of time by introducing into it an alkaline-earth metal, silica and/or a trivalent rare earth. The description also refers, by way of example, to a support based on a refractory oxide within the meaning of Claim 1, which already includes - that is, independently of the active phase - cerium oxide (one such trivalent rare earth) together with alumina (page 2, lines 44 to 47).

The Board is consequently of the opinion that Claim 1, interpreted in conjunction with the description pursuant to Article 69(1) EPC, defines a catalyst in which a quantity of cerium of between 2.5 and 4.4 % by weight relative to the support actually contributes to the conversion activity of the catalyst in its active phase, it being possible to incorporate any additional amounts of cerium not included in that quantity of between 2.5 and 4.4%, in the same way as other stabilisation elements, into the support structure based on a refractory oxide in order to improve its thermal stability.

Since the function actually performed by cerium is closely linked to its oxidation state and the latter can be determined by spectroscopic methods, as the respondents convincingly put forward, the inclusion of a specific amount of cerium either in the support or in the active phase as defined above is an objectively recognisable technical feature of all catalysts. Consequently, the interpretation adopted does not detract from the clarity of the definition of subject-matter according to Claim 1.

7. Novelty (...)

8. Inventive step (...)

9. For these reasons and taking into consideration the amendments made by the respondents according to their main request, the patent and the invention to which it relates meet the requirements of the Convention, so that the patent as amended may be maintained (Article 102(3) EPC). Respondents' alternative request

10. Under these circumstances, since the respondents' main request can be allowed it is not necessary to examine their alternative request.

ORDER

For these reasons it is decided that:

1. The contested decision is set aside.

2. The case is remitted to the department of first instance with the order to maintain the patent as amended, on the basis of the following documents:

- Claims 1 to 12 submitted during oral proceedings on 24 July 1990 as the main request;

- description page 2, line 1, to page 8, line 42, accompanying the communication pursuant to Rule 58(4) EPC issued on 10 January 1986.