Summary of Facts and Submissions
I. European patent No. 7081 containing ten claims was granted on 11 November 1981 on the basis of European patent application No. 79 102 315.3 filed on 9 July 1979 claiming priority of the earlier application of 13 July 1978 (DE-2 830 787). Claims 1, 4, 5 and 6 read as follows:
"1. A process for the manufacture of a nitrogen-containing crystalline metal silicate having a zeolite structure from silicon dioxide and metal oxides and/or metal hydroxides, characterized in that the crystallization is carried out in the absence of an alkali metal, in an aqueous solution of hexamethylenediamine.
4. An aluminum silicate zeolite manufactured as claimed in claims 1 to 3.
5. A borosilicate zeolite manufactured as claimed in claims 1 to 3.
6. A metal silicate zeolite manufactured by calcining the amine- containing form of a zeolite as claimed in claim 4 or 5."
II. The opponents filed opposition to the grant of the European patent on 11 August 1982, requesting that the patent be revoked owing to lack of novelty. The grounds referred among other things to new citations.
III. The Opposition Division rejected the opposition on 13 October 1983, arguing essentially that the subject-matter of Claim 1 differed in two important respects from the relevant state of the art, i.e. DE-A-2 442 240 (1) and US-A-4 016 245 (6), and was therefore new. Nor did the state of the art suggest any obvious reason for using hexamethylenediamine in the preparation of zeolites. It was surprising that an alkali-free zeolite could be prepared direct by the process according to the contested patent. The other citations had been published in the priority period and, since the claim to priority was valid, had to be disregarded; priority was not forfeited merely because the results of the analyses in the patent specification examples and in the priority documents were not identical. The application on which priority was based did not need to be identical in its wording with the subsequent application. The patent was maintained as amended with Claim 1 as follows still valid:
"1. A process for the manufacture of a nitrogen-containing crystalline silicate of trivalent metals having a zeolite structure from silicon dioxide and metal oxides and/or metal hydroxides, characterized in that the crystallization is carried out in the absence of an alkali metal, in an aqueous solution of hexamethylenediamine."
IV. The opponents filed an appeal against this decision on 12 December 1983, submitting grounds on 12 February 1984. Following a communication from the Board dated 11 February 1985 questioning the substantive allowability of Claims 4 to 6 and of Claims 7 to 10 (use claims), oral proceedings were held on 26 November 1985.
V. The appellants' submission may be summarised approximately as follows: (a) A patent could not be valid if the essence of what was claimed conflicted with the relevant part of the description in as much as the claim required the absence of alkali, whereas the examples demonstrated the presence of alkali. This was borne out by the rest of the description, where the use of chemicals with a low sodium content, i.e. containing sodium, was recommended for the preparation of zeolites and it was stated that traces of sodium accelerate crystallisation. (b) In particular, the patent proprietors had reduced by a whole power of ten the sodium values in the examples in the contested patent, i.e. the values on which priority was based, compared with those in the prior application. This was not a matter of correcting typing errors, but of making a significant correction to the technical content which was not supported by the disclosure in the prior application; a chemical application always included embodiments illustrating the subject-matter of the patent, which in this case were incorrect and could not be corrected subsequently. The contested patent could not therefore validly claim priority. (c) Clear and readily comprehensible terms used in the claim ruled out a different interpretation based on other definitions in the specification. Accordingly, the claimed subject-matter could not be reproduced and the patent did not disclose a teaching which could be implemented by the skilled person. (d) The loss of priority meant that DE-A-2 817 576 (2) and DE-A-2 817 577 (3), which expressly mentioned the use of hexamethylenediamine, prejudiced the novelty of the contested patent. Moreover the claimed process and the products did not involve an inventive step because they did not bring about a substantial improvement compared with the results according to (1). An extrapolation from the information given in the examples in (1) would have pointed to a further reduction in the alkali content below 0.01% by weight if the amine content were increased. (e) In view of the uncertainty about the actual alkali content in the zeolites in the examples, the advantages of the results set out in them were dubious and ought not to be taken into consideration. Although it was known that a reduction in the alkali content of zeolites by ion exchange and calcination resulted in an asymptotic approximation to an extreme value ("plateau"), it was denied that the products in the contested patent with a low alkali content could not also be obtained by conventional methods.
VI. The respondents disagree. The skilled person undoubtedly interpreted "absence" of alkali as meaning "essentially free" of such ions; after all, it was not technically feasible to exclude sodium entirely owing to its widespread presence as an impurity in the environment and therefore in the natural starting materials for the preparation of zeolites. This interpretation was also indicated by the description, in which "absence of" was defined in effect as "essentially free of" (p. 3, lines 11-12). This meant that the skilled person was simply expected to use chemicals containing as little alkali as possible (p. 3, lines 19-20). That interpretation had also been recognised by a court in the United States. Accordingly, the process was practicable and resulted in substantially improved products which could not be obtained by known methods.
VII. The appellants request that the contested decision be set aside and the European patent revoked. They request in the alternative that the following points of law be referred to the Enlarged Board of Appeal:
1. Is a claim postulating a specific technical requirement (in this case, absence of alkali) valid if the description gives contradictory technical instructions throughout (in this case, presence of alkali or sodium), in other words clearly does not support the claim?
2. Is a basic technical point which is essential to the claim (in the characterising portion of the main claim) still covered by the priority of the original application if this basic point has been substantially amended vis-à-vis the original application (in this case, by a power of ten)?
VIII. The respondents (patent proprietors) request that the appeal be dismissed and the patent maintained with Claims 1 to 5 as maintained by the Opposition Division subject to the first sentence of the description on page 3, paragraph 3, lines 27 to 28, being replaced by the following paragraph: "The zeolites manufactured according to the invention are suitable as catalysts for the conversion of hydrocarbons, e.g. in cracking and in isomerization and alkylation reactions, and for converting methanol and/or dimethylether into unsaturated hydrocarbons by splitting at a high temperature."
They request in the alternative that the patent be maintained with the further limitation that Claims 4 and 5 be deleted.
Reasons for the Decision
1. The appeal complies with Articles 106 to 108 and Rule 64 EPC and is therefore admissible.
2. The objection that the main claim is unclear is without substance; the proposal according to the patent that the process be carried out in the absence of alkali is addressed to the skilled person, who does not rely solely on the literal meaning of the text but is quite well aware that chemicals used for technical purposes are never entirely sodium-free. Accordingly, the teaching of Claim 1 considered objectively can only be taken to mean that in the preparation of zeolites it is necessary to exclude alkali as far as possible by keeping to a minimum the amount of alkali impurities in the starting materials used. The Board takes the view that any skilled person would interpret the technical teaching of the claims in this way, so there was no need to clarify the wording.
3. Any doubts that might nonetheless occur to the mind of a skilled person would be removed by the description. Here it is stated that "alkali-free" as used in relation to the invention means "essentially free from sodium ions" (cf. page 3, lines 11-12). It is expressly pointed out in this connection that the residual alkali content in the resulting zeolites is caused solely by impurities in the chemicals used as starting materials and that chemicals with a low Na content are generally preferred (cf. page 3, lines 12-21). The fact that Na traces can also accelerate zeolite crystallisation (cf. page 3, lines 17-18) does not conflict with this recommendation since the intention is as far as possible to allow only traces of Na. The Board considers that the teaching according to Claim 1 of the contested patent is not inconsistent with the description and that the interpretation which would naturally suggest itself to the skilled person is that the two readily complement each other. Consequently, the first point of law raised by the appellants is devoid of any basis. Under these circumstances, since the availability of such "alkali- free", i.e. largely alkali-free, chemicals is beyond doubt, the feasibility of the process is beyond doubt too (cf. the description, page 3, lines 14-24). The invention is therefore disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.
4. Nor is there any substance to the objection that the present patent does not qualify for the claimed right of priority. The appellants' view that correcting by a power of ten the sodium content of the zeolites prepared in accordance with some of the examples in the prior application must result in loss of priority disregards the fact that the priority for alkali-free zeolite preparation is based in the present case not on these examples but on the broader disclosure in Claim 1 and on page 6 of the prior application. However, even if the extent to which the zeolites are free of alkali were a decisive factor, the Board sees no reason for questioning the values corrected vis-à-vis the prior application; after all, the process inevitably producing the given result has remained unchanged. Moreover the opponents and appellants, with whom the onus of proof rests, have neither claimed nor shown convincingly that the corrected values are not in fact obtained. The examples called into question do not therefore go beyond the scope of the original disclosure, but have merely been corrected - and this cannot at present be refuted - in respect of a single value measured on the product of the process. This means that the patent in question enjoys the priority claimed in all those of its embodiments relevant in the present context. It should perhaps be noted in passing that, although the Na20 value has been corrected by a power of ten, the corrected values (0.002 or 0.0035%) are not substantially below the unchanged sodium content of 0.004% by weight from Example 1 in the European patent application, which is identical in content with that in the prior application.
5. Given this clear-cut situation it was not possible to accede to the appellants' request that the second point of law raised by them, concerning priority, be submitted to the Enlarged Board of Appeal.
6. Of the two citations published before the priority date of the contested patent, (1) is closest to the subject-matter of the patent. This document describes a process for preparing crystalline, nitrogen-containing zeolites in the presence of primary amines such as propylamine. The synthetic zeolites prepared in this way are already meant to have a reduced alkali content of not more than 0.2%. Although the operation is carried out in the presence of substantial quantities of sodium (up to one third in relation to the silicon dioxide used, see Examples 1, 13, 15 and 23), the best results with N-propylamine fluctuate between 0.01 and 0.07% of Na20 (occasionally with "less" than 0.01% in the case of isopropylamine and ethylamine, see the figures for Examples 8 and 12 in Tables I, page 16, and II, page 17). With higher amines the alkali content increases (Table II, Examples 13 to 26). It must be possible to use the products "direct as a catalyst without intermediate precalcination or cation exchange" (page 3, lines 17-19). However, the only relevant example of use merely concerns the use of a zeolite previously subjected to ion exchange with ammonium chloride and then calcined (page 17, last paragraph, and page 18, lines 1-4).
7. Given this state of the art, the technical problem consisted in providing a process for preparing zeolites with a yet lower alkali content in one stage, i.e. without complex ion exchange. To solve this problem it is proposed that crystallisation of the zeolite be carried out (essentially) without alkali in an aqueous solution of hexamethylenediamine. Without ion exchange, the subsequent products obtained by calcination have a sodium content of 0.002 to 0.004% by weight when aluminosilicate is added (Examples 5 and 1) and of 0.0035 to 0.008% by weight when borosilicate or arsenic silicate is added (Examples 7 and 9 respectively). These results suggest that the problem is indeed solved.
8. Neither of the two proposed features of the solution is disclosed in the relevant citations. The subject-matter of Claim 1 is thus new.
9. It therefore has to be established whether the proposed solution involves an inventive step.
9.1 It is significant that the state of the art describes the use of considerable quantities of Na20, for example in the form of sodium aluminate or sodium silicate, in order to dissolve the SiO2 and promote crystallisation. For example, citation (1) uses quantities of Na2O amounting to up to one third of the quantities of SiO2 in every example. Citation (6), too, adopts this method of preparation, which emulates the formation of zeolites under natural circumstances. The appellants do not dispute this characteristic, which is found throughout the state of the art. By contrast, the procedure according to the patent in question represents a departure from the known method of zeolite preparation as practised on a large scale and without any change in this respect for many decades. This involved a risk in so far as, at the least, it was uncertain whether and under what circumstances it was possible to dispense with sodium oxide acting as a solubiliser for the zeolite-forming oxides and at the same time as a crystallisation accelerator.
9.2 But even assuming that the skilled person intent on reducing the alkali content in the zeolites had thought of effecting this reduction in the starting materials themselves and had dismissed the grave misgiving about the dual role of the alkali, the state of the art would not have suggested the simultaneous use of hexamethylenediamine prescribed in the contested patent; no hint at this is contained in the state of the art. Although it was known that zeolites could be prepared in the presence of amines in a general form (albeit in the presence of substantial quantities of alkali), there could have been no predicting the advantages which indisputably occur when hexamethylenediamine is used and which the solution to the problem in question was meant to provide. Citation (1) shows that extension of the methylene chain impairs the results (cf. Examples 13-26 in conjunction with Table II, page 17). Citation (6) uses ethylenediamine, giving a content of over 0.02% by weight of sodium (equivalent to 0.01 mol% of Na2O relative to Al2O3 in accordance with Table 2A, column 11, as can be seen by comparing column 9, lines 18 and 22). The values with this diamine are thus much worse than with the corresponding monoamine in Example 12 of (1). Accordingly, the skilled person had no reason to expect better results than those in (1) by using diamines with a longer chain.
9.3 The subject-matter of Claim 1 and of the dependent Sub-claims 2 and 3 therefore involves an inventive step.
10. The direct products of the claimed process contain hexamethylenediamine incorporated in the intracrystalline pores (page 3, lines 41-42). Two specific variants, aluminosilicate and borosilicate zeolites, are expressly claimed (Claims 4 and 5). They are therefore new, together with the processes used to prepare them according to Claim 1. Defining them by product-by- process parameters is justified because the precise structure of these zeolites is unknown. Such claims, however, have to be interpreted in an absolute sense, i.e. independently of the process. If, as in the present case, their subject-matters as such are new, they still do not involve an inventive step merely because the process for their preparation does so (cf. "Claim Categories/IFF" T 150/82, OJ 7/1984, p. 309 and Decision T 248/85 of 21 January 1986 to be published); in order to be patentable, the claimed product as such must be a solution to a separate technical problem which is not obvious in the light of the state of the art.
11. The closest state of the art with regard to the zeolites in Claims 4 and 5 is again (1), which discloses crystalline, nitrogen-containing zeolites with a reduced alkali content which can be used as catalysts after calcination. The technical problem vis-à-vis this state of the art consists in providing primary products, further improved with regard to their alkali content, for such catalysts. This problem is solved according to the two substance claims by producing new precursors for calcined zeolites. These precursors differ from the products according to (1) not only in the type of incorporated amines but particularly in respect of their alkali content.
12. The respondents stated that zeolites known as catalysts or precursors thereof had not so far been available in this quality, i.e. with such a low alkali content (cf. the patent specification, page 2, lines 22-25). They further drew attention to their unsuccessful attempts to remove residual alkali from known zeolites with a higher alkali content by repeated ion exchange followed by calcination. Nor did either the general knowledge of the skilled person or the relevant literature point to any known method of obtaining such low alkali values as those in the contested patent. The appellants have conceded that the usual methods, i.e. ion exchange and calcination, result only asymptotically in a "plateau", i.e. an extreme sodium content value (cf. (1), page 7, lines 17-21). Although they nevertheless dispute the contention that there was no way of removing the residual alkali they have not been able to indicate a specific method suited to this purpose or even to suggest the bare outlines of such a method. The Board is unable on the strength of its own specialised knowledge to espouse the assertions of either the appellants or the respondents. It is more inclined to take the respondents' view, however, for if the state of the art had been capable of delivering zeolites with such a low alkali content as those obtained according to the teaching of the contested patent, this fact would certainly have been reflected in the technical literature or in technical knowledge in some other form capable of being substantiated. This not being the case, the Board believes that the teaching according to European patent No. 7 081 made it possible for the first time to prepare zeolites of the required quality. Regardless of that, however, it is not sufficient in opposition proceedings for the opponent to impugn a granted patent with an assertion which cannot be substantiated. It is true that under Article 114(1) EPC the European Patent Office, in proceedings before it, examines the facts of its own motion and is not restricted in this examination to the facts, evidence and arguments provided by the parties and the relief sought. But if the European Patent Office is unable to establish the facts of its own motion, it is the party whose argument rests on these alleged facts who loses thereby. This is the situation here. The two parties have made contrary assertions concerning the desired elimination of alkali. In such cases the ruling goes against the opponent as appellant if he is unable to substantiate an assertion which could disprove the existence of an inventive step. It was up to the opponents to name a method in the state of the art whereby it was possible prior to the filing date to prepare by other means zeolites free of alkali to the same degree as those in the patent in question. The opponents were unable to name any such method; nor is the Board aware of one. Accordingly, the opponents' assertion can only be treated as an unproven supposition which cannot counter the assumption that the granted European patent involves an inventive step.
13. The Board did not inform the parties in accordance with Rule 58(4) EPC. Under that provision, which by virtue of Rule 66(1) EPC is applicable to appeal proceedings mutatis mutandis, the Board of Appeal must, before deciding on the maintenance of the European patent in the amended form, inform the parties that it intends to maintain the patent as amended and invite them to state their observations within a period of one month if they disapprove of the text in which it is intended to maintain the patent. The Board maintained the patent with Claims 1 to 5 and with two minor amendments in the description, whereas the Opposition Division had maintained it with Claims 1 to 10. If the wording of Rule 58(4) EPC were taken literally, it would no doubt have been necessary to follow the procedure in accordance with Rule 58 EPC since the extent of the patent had been altered by the deletion of Claims 6 to 10 (one substance claim and all the use claims) and by an amendment - albeit minor - to the description.
14. However, the Board takes the view that it is as much the intent and purpose as the literal wording of Rule 58(4) that have to be observed in opposition appeal proceedings. The Board in fact doubts whether Rule 58(4) EPC always applies when oral proceedings have taken place before it. In the Board's view, Rule 58(4) EPC is intended to ensure that due account is taken in opposition proceedings of the principles of due process set out in Article 113 EPC. The Board recognises the general justification of Rule 58(4) EPC where no oral proceedings have taken place and it is intended that the patent be maintained in the amended form by the written procedure. Generally speaking, the Board considers it necessary in the written procedure to inform the parties in writing of the intention to maintain the patent in the amended form. By contrast, this obvious need to inform the parties under Rule 58(4) EPC does not apply to the same extent in a case involving oral proceedings since the subject-matter is discussed in detail with the parties anyway. Oral proceedings therefore represent the best way of ensuring that decisions are based on grounds or evidence on which the parties concerned have had an opportunity to present their comments. If oral proceedings are not held, other guarantees must be provided to ensure that this requirement is adequately catered for. In the written procedure, the guarantee consists in the fact that the parties are always informed in accordance with Rule 58(4) EPC. As regards the written procedure, therefore, the need for the parties to be informed in accordance with Rule 58(4) EPC is incontrovertible and mandatory.
15. Oral proceedings, on the other hand, generally afford the parties an adequate opportunity to comment on a proposal to maintain the European patent in the amended form. Only when the parties cannot reasonably be expected to state their definitive observations on maintenance in the amended form during oral proceedings - for example, because the amendments are so fundamental or numerous that their significance cannot immediately be appreciated - would it be necessary even after oral proceedings to inform the parties in accordance with Rule 58(4) EPC in order to ensure that the principles governing the basis of decisions are properly observed. If, on the other hand, the amendments are such that the party or his professional representative can appreciate their significance - if necessary, after the oral proceedings have been interrupted so that the parties can confer among themselves - there will be no need to inform the parties in accordance with Rule 58(4) EPC. The same applies if the intended amendment, although very far-reaching or extensive, has been made known to the parties by the Board under an interim order prior to the oral proceedings. The Board considers it unnecessary in all these cases to inform the parties in accordance with Rule 58(4) EPC because due regard has already been had to the intent and purpose of this provision.
16. The Board therefore believes the parties should be informed in accordance with Rule 58(4) EPC if they would not otherwise have an adequate opportunity to present their comments. Accordingly, it has to be considered in each individual case whether or not the parties ought to be informed in accordance with Rule 58(4) EPC. Great care needs to be exercised in considering this question as it is a matter of due process and hence fundamental to equitable proceedings. Under the European Patent Convention the Board is particularly well equipped for this purpose because, unlike the Opposition Division which decides on the case at first instance, at least one legally qualified member always sits on the bench of the Board of Appeal (cf. Articles 19(2) and 21(4) EPC). This composition guarantees as far as possible that the parties have an adequate opportunity to present their comments in opposition appeal proceedings. The difference in the memberships of Opposition Division and Board of Appeal thus justifies applying Rule 58(4) EPC in different ways. Before the European patent is maintained in the amended form in proceedings before the Opposition Division, therefore, the parties should always be informed in accordance with Rule 58(4) EPC even if oral proceedings have been held; whereas in opposition appeal proceedings the Board decides from case to case whether or not this is necessary. When in doubt, the Board too will always favour informing the parties in accordance with Rule 58(4) to ensure that they have an adequate opportunity to present their comments. This differing application of Rule 58(4) EPC before Opposition Division and Board of Appeal is also in line with the text of the Convention: Rule 66(1) EPC stipulates not that Rule 58(4) EPC has to be applied in appeal proceedings, but that the provisions relating to proceedings before the department of first instance are applicable to appeal proceedings "mutatis mutandis". This means that, when the same procedural provisions are applied, the above-mentioned differences in the memberships of the deciding bodies are to be taken into account.
17. Applying the principles elucidated above to the present case, the Board was able to dispense with informing the parties in accordance with Rule 58(4) EPC. The extent of the patent was amended only in so far as Claims 6 to 10 were deleted completely, the essential content of the Use Claims 7 to 10 being incorporated almost verbatim into the description. The effects of this amendment on the scope of the protection afforded by the patent are very easy to perceive, so that a discussion during oral proceedings was quite sufficient to ensure that the parties had adequate opportunity to present their comments. The parties gave no indication during the oral proceedings that they needed more time - for instance, an interruption of the oral proceedings or even a period in which to present their comments - in order to examine this amendment. Nor did the Board see any such need. The Board's decision not to inform the parties under Rule 58(4) EPC was therefore correct.
18. Under Article 112(1) EPC the Board of Appeal refers any question to the Enlarged Board of Appeal of its own motion or at the request of a party if it considers the Enlarged Board's decision necessary. As already explained in some detail under 3. to 5. above, the Board sees no need for a decision by the Enlarged Board of Appeal with regard to the questions formulated by the appellants. Quite apart from that the general prerequisities for a referral to the Enlarged Board of Appeal are not fulfilled, given that questions may only be referred to the Enlarged Board in order to ensure uniform application of the law or if an important point of law arises. Neither of these requirements is met in the present case since the law is applied within the framework of existing case law concerning the understanding of the average skilled person. The Board is not departing from the case law laid down by another Board nor is it deciding an important point of law whose resolution would be of general interest for the future. The Board is merely applying proven principles of law to an individual case. There is therefore no question of referring the matter to the Enlarged Board of Appeal.
ORDER
For these reasons, it is decided that:
1. The contested decision is set aside.
2. The patent is maintained with Claims 1 to 5, as requested, and with the following amendments: (a) In the description, the first sentence of paragraph 3 on page 3, lines 27 - 28, is to be deleted and replaced by the paragraph indicated under VIII. (b) On page 3, paragraph 4, line 43, "(calcination)" is to be added after "burning".
3. The request that the points of law submitted by the appellants be referred to the Enlarged Board of Appeal is refused.
