T 0291/85 (Catalyst) of 23.7.1987

Summary of Facts and Submissions

I. European patent No. 11 184 was granted on 11 May 1983 on the basis of European patent application No. 79 104 244.3, filed on 31 October 1979 claiming a German priority of 11 November 1978. It had ten claims, independent Claims 1, 9 and 10 of which read as follows: "1. A catalyst consisting of: A) a rare earth carboxylate having the formula R1 M R2 - C - C02 (1) R3 3 B) an aluminium alkyl Al(R4)3 and/or (R4)2AlH and C) a further Lewis acid. In the formulae M is a trivalent rare earth element with an atomic number between 57 and 71, R1, R2 and R3 are identical or different alkyl radicals with 1 to 10 carbon atoms, the sum of all the C atoms in the substituents being between 6 and 20, and R4 is an alkyl radical with 1 to 10 carbon atoms, with the exception of a catalyst which contains a reaction product of component A of formula 1 in which the sum of all the Catoms in the substituents is between 6 and 19, with a proportion of component B, when B is aluminium trialkyl.

9. A process for the polymerisation of conjugated dienes in homogeneous solution, wherein a catalyst as claimed in Claims 1 to 8 is used.

10. A process for producing a catalyst as claimed in Claims 1 to 8, wherein a) a rare earth carboxylate having the formula R1 M R2 - C - C02 R3 3 b) an aluminium alkyl Al(R4)3 and/or (R4)2AlH and c) a Lewis acid are mixed in any sequence in an inert organic solvent at temperatures of -30 to +80°C."

II. The present appellants filed opposition to the patent on 10 February 1984 on the grounds of lack of novelty and inventive step, citing a number of documents of which ultimately only (1b) GB-A- 1 294 725 remained under discussion.

III. After the opponents had withdrawn their alternative request for oral proceedings on 18 June 1985 the opposition was rejected in written proceedings by a decision dated 8 October 1985. The decision recognises the subject-matter of the patent as novel on the grounds that none of the citations disclosed a catalyst system in which one of the components was a salt of a rare earth with a tertiary monocarboxylic acid, nor the preparation or use of such a catalyst. The subject-matter of the patent also involved inventive step. ...

IV. The opponents appealed against this decision on 4 December 1985, paying the prescribed fee at the same time, and filed a statement of grounds on 7 February 1986. ... They maintained that the patent in suit was not clearly delimited vis-à-vis (1b), in which it was already stated that freshly prepared catalysts are often more active than those which have undergone ageing.

V. The respondents countered by drawing a distinction in the disclosure of (1b) between the statement of the prior art, where salts of rare earths containing tertiary monocarboxylic acids are not mentioned, and the description of the invention which included mention of the ageing of the catalyst in the presence of a conjugated diene, which was not referred to in the patent in suit. The mere fact that ageing was not a factor justified regarding the subject-matter of the patent as novel and involving inventive step. ...

VI. In oral proceedings on 23 July 1987 the respondents defended their patent only in a limited scope. While Claims 2 to 9 remained unchanged, the beginning of Claim 1 no longer read "A catalyst consisting of ..." but "A catalyst which is homogeneously soluble in solvents for diene polymerisation and obtained by adding and mixing the catalyst components to the polymerisation formulation, consisting of ..."; and in Claim 10 the word "mixed" is replaced by the words "added to the polymerisation formulation". As they confirmed orally when requested, the respondents thereby restricted themselves to catalysts prepared in situ (Claims 1 to 8), processes for their preparation (Claim 10) and polymerisation processes using catalysts thus prepared (Claim 9).

Reasons for the Decision

5. The contested patent relates to a catalyst (Claims 1 to 8), a polymerisation process in which the said catalyst is used (Claim 9) and a process for preparing it (Claim 10). Since if the catalyst itself is novel and involves an inventive step the same will certainly apply to the processes for its preparation and use - though the converse is of course not necessarily the case - the Board will first consider only the catalyst per se.

6. The closest and - certainly once (8) has been eliminated - only relevant prior art is (1b). It describes a catalyst for diene polymerisation, taking as its starting-point a previous prior art to which reference is made but whose source is not identified and which will be discussed further below. The catalyst has the following components (cf. Claim 1): (a) an organoaluminium compound with Al-C bond(s), such as triethylaluminium (page 2, line 29) or diethylaluminium hydride (page 2, lines 9 to 10); (b) a metal co-ordination compound whose metal is in particular a rare earth (atomic No. between 57 and 71), such as cerium neodecanoate and neodymium neodecanoate (page 2, lines 108 and 112), being one of the salts of rare earths with tertiary monocarboxylic acids (more precisely with trialkyl acetic acids); (c) a compound with one or more "halidions", e.g. diethyl aluminium bromide (page 3, lines 14 to 15); and, as an essential component, (d) a product obtained by advance preparation and ageing of the above system in the presence of smallish quantities of a conjugated diene (page 7, lines 36 to 41).

7. The catalyst of the patent in suit whose sole components A, B and C (as witness the words "consisting of" in Claim 1) are largely similar, even if not identical, to the components (b), (a) and (c) of the catalyst of (1b) - cf. the general formula (1) in Claim 1 and the mention of triethylaluminium (page 4, line 29) and diethylaluminium hydride (page 4, line 38) and of the Lewis acid diethylaluminium bromide (page 4, line 57) - nonetheless differs from that described in (1b) at least in the absence of component (d), or - put otherwise - in that the catalyst of the patent in suit is prepared by adding and mixing its components (A, B and C) to the polymerisation formulation, hence without advance preparation or ageing in the presence of diene. If therefore the teaching of the patent in suit is compared solely with the development by (1b) of the prior art referred to without indication of source therein, the teaching may be said to be novel in the light of the difference referred to.

8. The appellants, however, have pointed out that (1b) also refers to a prior art in which an appropriate catalyst system may consist of (a') a trialkyl aluminium or alkyl aluminium hydride, (b') a compound of a metal of Group IIIB in the periodic table, and (c') an alkyl aluminium halide. The citation thus discloses (cf. page 1, lines 22 to 29) a catalyst system which, like that described in the patent in suit, consists of only three components, components (a') and (c') in the prior art referred to in (1b) clearly corresponding to components (a) and (c) in the development of that prior art described in (1b) and to components B and C in the patent in suit. The appellants hold that, since the teaching in (1b) is a development of the prior art referred to therein and described above, the specific statements for example on page 2, lines 105 to 116 must be read in conjunction with the general account of the prior art referred to in (1b), page 1, lines 22 to 29, as an overall disclosure which would then anticipate the subject-matter of the contested patent.

9. The Board does not share this view.

9.1 Firstly the Board would point out - though not directly relevant - that the account of the prior art referred to in (1b), page 1, lines 22 to 29, does not mention whether the catalyst in question is prepared in advance or in situ. Even if the combination desired by the appellants were permissible it would still be doubtful whether it would prejudice the novelty of the subject-matter of the patent in suit; this would, after all, require the inclusion of the disclosure on page 3, lines 64 to 73, of (1b). However, this question may be left aside for the following reasons:

9.2 It goes without saying that disclosure in a prior publication -in this case (1b) - always includes not only what it presents as the teaching of the invention but also what it refers to as the prior art - which in this case are the statements on page 1, lines 22 to 29. However, when examining for novelty to read into an account of the state of the art couched in very general terms -as here in the case of (b') - specific details of the inventive teaching of the same document is permissible only where a person skilled in the art would when reading this document in fact have made this combination.

9.3 This would, for instance, be the case were a source to be cited for the prior art described and a specific, relevant disclosure to be derived from the original document or were the description of the prior art to refer directly to the appropriate passage in the description of the invention; such a combining of a specific feature from the description with the general description of the prior art could in certain circumstances be obvious to a skilled person merely in the light of his general technical knowledge. In the absence of such or similar circumstances, however, one cannot assume that a skilled person would necessarily have derived from the document a teaching based on a combination of this kind.

9.4 In summary therefore: if a citation gives detailed information about a further development of a prior art described only in very general terms without quoting a specific source, it is not permissible in examining for novelty to combine these general statements with the specific statements made solely in order to explain the said development unless a person skilled in the art would have made the combination when reading the citation.

9.5 In the present case the definition of component (b') on page 1, lines 26 to 28, of (1b) is extremely broad, covering any of a range of widely differing compounds of a variety of metals. There is no indication of source as referred to in the first half of the first sentence of point 9.3. Nor have the appellants explained why, in the light of his general knowledge or in any other way, a skilled person reading (1b) would have understood the reference in connection with the prior art to "compounds" of metals of Group IIIB as meaning precisely salts of rare earths with tertiary monocarboxylic acids or specifically with the neodecanoic acid mentioned in another context on page 2, line 94. Nor is the use in catalysts for diene polymerisation of trialkyl acetic acids or of their salts with rare earths mentioned anywhere in the remainder of the prior art which is not discussed in detail. The Board therefore fails to see how a skilled person should have deduced from (1b) three-component diene polymerisation catalysts containing salts of rare earths specifically with trialkyl acetic acids.

9.6 Even taking into account the appellants' arguments set out in section 8, therefore, the subject-matter of the patent in suit must be regarded as novel. ...

ORDER

For these reasons, it is decided that:

1. The contested decision is set aside.

2. The matter is remitted to the department of first instance with the order that European patent No. 11 184 be maintained on the basis of the documents handed over during the oral proceedings.