T 0273/84 (Silico-Aluminate) of 21.3.1986

Summary of Facts and Submissions

I. European patent application No. 79 400 119.8 was filed on 27 February 1979, claiming the priority of a French application of 2 March 1978, and European Patent No. 0 004 225 was granted on 14 July 1982 on the basis of the following four claims:

1. A process for the production of an alkali-metal silico-aluminate of type 4A by hot mixing at least one source containing silica and alumina with an alkali-metal hydroxide and water, one at least of the reactants being fed in in solid form, and at least partial crystallisation occurring simultaneously with the mixing step, characterised in that the reactants are mixed in proportions such that the initial medium is of the following composition, expressed in molar ratios:

SiO2/Al203 from 1.5 to 2.5

Na20/Si02 from 0.8 to 1.20

H20/Na20 from 7 to 15

and takes on the appearance of a solid mixture, said solid mixture then being left to develop until it re-disperses in the form of a suspension of silico-aluminate, which is filtered, washed and dried.

2. A process as claimed in claim 1, characterised in that the operating conditions are so controlled as to produce the state of a solid mixture in from 1 minute to 30 minutes.

3. A process as claimed in claim 1 or 2, characterised in that one reactant is introduced during the mixing and crystallisation operation.

4. A process for producing a silico-aluminate of type Na-P by hot mixing at least one source containing silica and alumina with an alkali-metal hydroxide and water, one at least of the reactants being supplied in solid form, characterised in that the reactants are mixed in proportions such that the initial medium is of the following composition, expressed in molar ratios:

SiO2/Al203 from 2.5 to 5

Na20/Si02 from 0.6 to 1

H20/Na20 from 12 to 30

and takes on the appearance of a solid mixture, at least partial crystallisation occurring simultaneously with the mixing step, said solid mixture then being left to develop in a hot state until re- dispersion thereof in the form of a suspension of silico-aluminate, which is filtered, washed and dried.

II. The appellants (opponents) filed a notice of opposition to the European patent by telex of 13 April 1983, confirmed by letter received on 15 April 1983, and requested that it be revoked on the grounds of lack of inventive step. The grounds for opposition were based on DE-C-1 038 017 (1) and were aimed exclusively at Claim 1 of the opposed patent.

III. The Opposition Division rejected the opposition by decision of 24 September 1984 on the grounds that the process forming the subject-matter of Claim 1 differed substantially from the cited prior art in that the very narrow ranges of molar ratios were within those indicated in citation (1) and at least one of the reactants was fed directly into the reactor in solid form. Since the teaching of citation (1) was not such as to suggest to a skilled person the operating conditions claimed in the opposed patent, the Opposition Division concluded that Claim 1 met the requirements of novelty and inventive step.

IV. The appellants (opponents) filed an appeal against this decision, at the same time paying the appropriate fee. The notice of appeal and the statement of grounds were received on 20 November 1984.

V. The appellants (opponents) requested revocation of the opposed patent on grounds of lack of novelty and inventive step in the case both of Claims 1 to 3 and of independent Claim 4. They cited four new documents in support of their arguments, although the first, corresponding to FR-E-83 942, had already been taken into account during examination. The citations were: (2) DE-A-1 467 051 (3) DE-B-2 725 496 (4) FR-A-1 213 628 (5) US-A-3 008 803

VI. The respondents (patent proprietors) filed observations received on 11 March 1985 rebutting the arguments set out in the appellants' statement of grounds and drawing attention to the characteristic features of the process claimed, namely the solid appearance of the mixture, the fact that one reactant was fed in in solid form, and the restriction regarding molar ratios. The respondents requested that the appeal as a whole be rejected, hence that the patent be maintained without amendment.

Reasons for the Decision

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

2. Under Rule 66(1) EPC, and unless otherwise provided, the Boards of Appeal consider an appeal by applying the provisions relating to proceedings before the department which took the decision appealed against. Under Rule 55(c) EPC a notice of opposition must contain a statement of the extent to which the European patent is opposed and of the grounds on which the opposition is based as well as an indication of the facts, evidence and arguments presented in support of these grounds. The period for opposition is nine months (Article 99(1) EPC). In this case, however, the appellant cited four new supporting documents in the statement of grounds for appeal against the decision of the Opposition Division, hence after the period for opposition had expired. The question therefore arising is whether in appeal proceedings following opposition a Board of Appeal may allow new documents to be introduced or whether it must consider the periods for opposition laid down in Article 99 EPC as applying. Article 114(2) EPC states that the European Patent Office may disregard facts or evidence which are not submitted in due time by the parties concerned. However, this discretionary power is given to departments of the EPO clearly only in order to ensure that proceedings run smoothly and to forestall tactical abuse. The Guidelines for Examination in the EPO stress the promptness with which documents in support of an opposition must be submitted and the time limits for doing so (Guidelines D-IV, 1.2.2.1(f), last paragraph, D-V, 2; E-VI, 2; and OJ (EPO) 9/1985, pp. 272, 277, 278). Nonetheless, Article 114(1) EPC enunciates a principle which must be adhered to by a department of the EPO in all proceedings before it, namely examination by the EPO of its own motion; "In proceedings before it, the European Patent Office shall examine the facts of its own motion; it shall not be restricted in this examination to the facts, evidence and arguments provided by the parties and the relief sought." It follows from this Article that the examination is not restricted to, but must include, the evidence furnished by the parties. Furthermore this obligation on the EPO to examine of its own motion applies in all proceedings. In the present case citation (3) cannot be ignored, since it raises doubts as to the novelty of the patent's subject-matter and thus as to the soundness of the impugned decision. The department of first instance must decide at its discretion whether the other three new documents are admissible.

3. The opposed patent relates to a process for producing an alkali-metal silico-aluminate by hot mixing at least one source containing silica and alumina with an alkali-metal hydroxide and water, one at least of the reactants being fed in in solid form, and the evolution of the mixture until it becomes a suspension of silico-aluminate which is then filtered, washed and dried. The type of silico-aluminate obtained is either 4A or Na-P, depending on the proportions of the reactants in the mixture. In the first case (Claim 1) the initial medium must be of the following composition, expressed in molar ratios:

SiO2/Al203 1.5 to 2.5

Na20/Si02 0.8 to 1.2

H20/Na20 7 to 15

In the second case (Claim 4) composition of the initial medium must be:

SiO2/Al203 2.5 to 5

Na20/Si02 0.6 to 1

H20/Na20 12 to 30

4. Of the various documents cited by the appellants (opponents), citation (3) is held by the Board to be the closest prior art. It describes a single-stage process for the preparation of zeolite A in which metakaolin is added to soda and water in a mixer so as to obtain a molar ratio of H20/Na20 of between 15 and 100. Examples 1 to 13 in citation (3) all involve the use of metakaolin, and hence constant molar ratios of Na20/Si02 and Si02/Al203 lying within the ranges claimed in the opposed patent. The constituents are mixed at a high temperature (85° C) and filtered, the filtrate then being washed and dried. According to this citation it is possible by the process described to obtain zeolite A of 90% or even 95% purity (see the claim, column 1, lines 44 to 47 and 62 to 68; column 2, lines 4 to 9 and 31 to 35; Example 1 and the table in columns 3 and 4).

5. In their observations filed subsequently to the statement of grounds the respondents (patent proprietors) acknowledged the prior disclosure of a H20/Na20 molar ratio of 15, but considered the process described in citation (3) to be contrary to the teaching of the opposed patent in which the components are mixed in solid form, and consequently held Claim 1 to be novel. This argument is open to question. Claim 1 of the opposed patent states merely that at least one of the reactants is fed in in solid form. But this is also the case of citation (3) (see Example 1). Furthermore, a delimitation vis-à-vis citation (3), though apparently quite feasible on the basis of a limit value for the molar ratio H20/Na20, would not dispel the doubts as to the inventive step involved in the subject-matter of Claim 1.

6. It is immediately clear from this newly established closest prior art, with no further consideration of the case being necessary, that the impugned decision of the department of first instance cannot stand. Examination as to patentability needs to be resumed on a new basis and the technical problem to be solved by the invention determined in the light of a new citation. That is primarily the task of the department of first instance. Were the Board itself to undertake this examination on the new basis and taking into account the state of the art as newly established, this would necessarily have the effect of bypassing one level of jurisdiction, which in turn would be contrary to the principle of equity followed by the Board. However, thus allowing the introduction of documents submitted after the period for opposition has expired could lead to abuses difficult to control. The Board accepts that to allow such documents necessarily means considerably lengthening the procedure and that certain limits must be set. In the Board's opinion those limits were not exceeded in the present case, for the reasons given in points 2, 4 and 5 above, since the inconvenience resulting from the lengthened procedure is here offset by the obligation imposed by Article 114(1) EPC on all departments of the EPO to conduct an examination of their own motion.

7. The Board must therefore set aside the decision of the department of first instance, without reference to the validity of its grounds. In so doing, the Board is availing itself of its power under Article 111(1) EPC in order to refer the matter back to the Opposition Division for renewed examination of Claims 1 to 4 of the opposed patent as to novelty and inventive step.

ORDER

For these reasons, it is decided that:

1. The impugned decision is set aside.

2. The case is referred back to the Opposition Division for consideration of the opposition to be resumed, with particular attention being paid to the new citation (3) filed with the statement of grounds on 20 November 1984.