T 0024/99 05-12-2002

I. The grant of European patent No. 0 394 487 in respect of European patent application No. 89 911 605.7, based on International patent application No. PCT/JP89/01067, which had been filed on 18 October 1989, was announced on 27 March 1996 (Bulletin 1996/13) on the basis of 13. claims.

Claims 1, 6, 9 and 13 as granted read as follows:

"1. Use of a polyoxyalkylene polyol having an[.] oxypropylene group content of at least 70 % by weight, a terminal oxyethylene group content of at least 5 % by weight, a number of hydroxyl groups of from 2 to 8, hydroxyl value (X mgKOH/g) of from 5. to 38 and a total unsaturation degree (Y meq/g) of not more than 0.04, provided that when X is from 32.5 to 38, Y satisfies the formula Y =< 0.9/(X-10), for the manufacture of a polyurethane flexible foam, having an impact resilience of the core of at least 70 % (measured in accordance with JIS K 6401) and a resonant frequency of not higher than 3.5 Hz (measured in accordance with JAS 0. B407-82), said manufacture comprising reacting at least one high molecular weight polyol selected from the group consisting of said polyoxyalkylene polyol and a polymer-dispersed polyol containing said polyoxyalkylene polyol as the matrix, a crosslinking agent having a molecular weight not higher than 600 and possessing at least 2. isocyanate-reactive groups and a polyisocyanate compound in the presence of assisting agents such as a catalyst, a foaming agent and a foam stabilizer."

"6. The use according to Claim 1, wherein the crosslinking agent is a polyol having a molecular weight of not higher than 600 per hydroxyl group and having from 2 to 8 hydroxyl groups."

"9. Use of a polyoxyalkylene polyol having an oxypropylene group content of at least 70 % by weight, a terminal oxyethylene group content of at least 5 % by weight, a number of hydroxyl groups of from 2 to 8, a hydroxyl value (X mgKOH/g) of from 5 to 38 and a total unsaturation degree (Y meq/g) of not more than 0.07, with X and Y being in the following relation: Y =< 0.9/(X-10) with the proviso that the formula is applicable in a range of x > 10 for the manufacture of a polyurethane flexible foam, having an impact resilience of the core of at least 70 % (measured in accordance with JIS K 6401) and a resonant frequency of not higher than 3.5 Hz (measured in accordance with JAS 0 B407-82), said manufacture comprising reacting a polymer-dispersed polyol wherein the matrix is the above-mentioned polyoxyalkylene polyol and fine polymer particles are dispersed stably in the matrix, from 0.2 to 10 parts by weight, per 100 parts by weight of the polymer-dispersed polyol, of a crosslinking agent having a molecular weight not higher than 600 and possessing at least 2 isocyanate-reactive groups and an aromatic polyisocyanate in an amount of from 0.8 to 1.3 equivalent of the total amount of the polymer-dispersed polyol, the crosslinking agent and water when a foaming agent contains water, in the presence of a catalyst, a foaming agent and a foam stabilizer."

"13. The use according to Claim 9, wherein the crosslinking agent is a polyoxyalkylene polyol having a molecular weight of not higher than 300 per hydroxyl group and a number of hydroxyl groups of from 3 to 8."

The remaining dependent claims 2 to 5, 7, 8 and 10 to 12 related to specific embodiments of the subject-matter of the independent Claims 1 and 9, respectively.

II. In this decision, each reference to the "application" is intended to mean the "application documents as originally filed".

III. On 16 December 1996 and 27 December 1996, respectively, Notices of Opposition were filed by two Opponents in which revocation of the patent in its entirety was requested. Both Opponents raised objections under Article 100(c) EPC and disputed the patentability of the claimed subject-matter under Articles 54 and 56 EPC on the basis of initially seven, later nine documents (Article 100(a) EPC) including

D3: US-A-4 687 851,

D5: US-A-4 098 729,

D6: US-A-3 925 266 and

D7: "Proceedings of the Fourth International Pacific Conference on Automotive Engineering", Melbourne (Australia) November 8 to 14, 1987, pages 299.1 to 299.8.

A further objection under Article 100(b) EPC was raised by Opponent I.

In oral proceedings before the Opposition Division held on 14 October 1998, the Patent Proprietor submitted two auxiliary requests. As the main request, rejection of the oppositions was requested.

(i) Both independent claims according to the first auxiliary request, a set of Claims 1 to 13, differed from the respective corresponding Claims 1 and 9 of the granted version only in that the definition of the crosslinking agent had been amended to read:

"a crosslinking agent having a molecular weight not higher than 600 per isocyanate-reactive group and possessing at least 2 isocyanate-reactive groups"

(ii) The second auxiliary request, a set of Claims 1 to 11, differed from the version as granted only in that the definition of the crosslinking agent in each of the above independent claims had been replaced, respectively, by the corresponding definitions in Claims 6 and 13 as granted (section I, above) which latter claims had then been deleted. As a consequence, Claims 7 to 12 were renumbered "6" to "11", and the dependencies in renumbered Claims 9 to 11 were corrected accordingly.

Hence, this amendment resulted in a definition of the crosslinking agent in Claim 1 to read as follows:

"a crosslinking agent which is a polyol having a molecular weight of not higher than 600 per hydroxyl group and having from 2 to 8 hydroxyl groups".

In Claim 8, as renumbered and amended, the respective passage read:

"a crosslinking agent which is a polyoxyalkylene polyol having a molecular weight of not higher than 300 per hydroxyl group and a number of hydroxyl groups of from 3 to 8".

IV. By decision announced at the end of the above oral proceedings and issued in writing on 2 November 1998, the Opposition Division revoked the patent.

In substance, it was held that the subject-matter according to the main request, i.e. the patent as granted, extended beyond the content of the application as filed (Article 100(c) EPC), that the first auxiliary request contravened Article 123(3) EPC and that the second auxiliary request lacked inventive step (Article 56 EPC) in view of a combination of D3 and D7.

In view of these findings, the Opposition Division concluded that there was no need to consider the further ground for opposition under Article 100(b) EPC raised by Opponent I in its Notice of Opposition.

V. On 22 December 1998, an appeal was lodged by the Appellant (Proprietor). In the Statement of Grounds of Appeal, received on 12 March 1999, the Appellant requested that the decision be set aside and the patent be maintained with the set of claims submitted as first auxiliary request in the opposition proceedings (main request; section III.i), above) or, alternatively, with the set of claims filed as second auxiliary request in those proceedings (first auxiliary request; section III.ii), above).

As in the opposition proceedings, where the validity of D7 as prior art had already been in dispute, the Appellant maintained its argument to the invalidity of this document as state of the art.

The Appellant argued that the amendments in both Claims 1 and 9 of the above main request would be admissible in view the embodiments of Claims 6 and 13, because these claims were appendant to Claims 1 and 9, respectively, and related to embodiments which, by referring back to Claim 1 and 9, were elements within the broader scope of those claims. Therefore the Claims 1 and 9 as granted would be understood by the skilled person as spelled out in the corrected version of these claims.

As regards the questions of patentability in view of the citations, the Appellant disputed the conclusions drawn by the Opposition Division.

VI. In their counterstatements dated 29 July 1999 and 21. September 1999, respectively, both Respondents supported the decision under appeal with respect to the question of Article 123(2) EPC and inventive step and requested that the appeal be dismissed. Additionally Respondent II (Opponent II) further pursued its novelty objection, and filed evidence to support its argument that D7 was prior art. D7 was suggested to be considered as the closest state of the art.

Both Respondents also objected to the wording of the new main and first auxiliary requests under Article 123(3) EPC. The insertion of "per isocyanate-reactive group" in Claims 1 and 9 of the main request broadened the scope of these claims considerably due to the fact that the fixed upper limit of the range of molecular weights of the crosslinking agent of "not higher than 600" was extended to at least 1200 when taking into account the minimum number of at least 2 such groups in the compound. With respect to the first auxiliary request, it was argued that a dependent claim could not be broader than the independent claim to which it was appendant and, consequently, its incorporation into the independent claim could not serve in a proper way to broaden the scope of protection of the patent in suit. In support of these arguments, reference was made to Decision G 1/93 (OJ EPO 1994, 541, in particular, point 13 of the reasons).

There was a clear inconsistency between the definition of the crosslinking agent in the granted version of Claims 1 and 6. However, the most a reader could derive from the patent specification was the conclusion that there was an error in one of its claims. However, the error could not be regarded as having been plainly obvious to the reader of the specification, because it had not been noted by any participant in the opposition proceedings, neither by the Opponents nor the Representatives of the Proprietor nor the Opposition Division, up to the oral proceedings of 14 October 1998.

The reader would have been entitled to take it that the main claim had been drafted with care, whereas less attention might well have been paid to the sub-claims. It was further argued that it was not so uncommon for there to be a failure to carry through amendments to a main claim thoroughly in making consequential amendments in the remainder of the description and claims. Hence, the reader was fully justified in supposing that Claim 1 meant what it said and, when noting the mistake, that Claim 6 as granted was erroneous.

VII. The opposition was transferred from original Respondent I to another company with effect of 28. October 1999, followed by a change of name of this Respondent (letter of confirmation dated 10 March 2001 by the transcription service of the EPO).

VIII. Oral proceedings were held on 5 December 2002. Before opening the floor to the parties, the Board initially made some provisional, preliminary remarks:

Whilst Claims 1 and 9 as granted required that the molecular weight of the crosslinking agent did not exceed 600, their new wording according to the main request included compounds having a molecular weight of 1200 or even more, because the presence of at least two isocyanate-reactive groups was required. Hence, the proposed amendment appeared to contravene Article 123(3) EPC).

With respect to the dispute whether D7 had been made available in due time to be considered as part of the prior art, it would have appeared from the message issued by the British Library dated 25 June 1999, which had been filed by Respondent II with its letter dated 21. September 1999, that D7 had been available to the public since 7 September 1988.

IX. The additional arguments presented by the Appellant during the oral proceedings to complement its written submissions can be summarised as follows:

An error had occurred in Claims 1 and 9 as granted. The error was obvious in view of the definitions of the molecular weight of the crosslinking agent in the main claim and in Claim 6 as granted, which were inconsistent with each other and led the reader of the patent in suit to rely on all the available material including the specification in its entirety and the contents of the file. The fact that there was an error had not been disputed by the Respondents as could be seen from their initial counterstatements to the Statement of Grounds of Appeal. The correction of the error would, however, and contrary to the statements of the Respondents, not constitute an amendment of the content of the claim, but only be of declaratory nature, to reinstate what had been the original intention of the applicant. It could not, therefore, contravene the two requirements of Article 123(2) and (3) EPC (G 3/89; OJ EPO 1993, 117).

Despite a number of theoretically and formally conceivable further variants, only one way was possible for the reader skilled in this art to carry out the correction, ie the one based on page 10, lines 16 to 18 (under the heading "Crosslinking agent"), where the molecular weight was clearly defined "as not higher than 600 per isocyanate-reactive group" rather than as an absolute limit of up to 600. Moreover, Claim 6 could only be subsumed under Claim 1, if Claim 1 was read and interpreted as suggested by the wording according to the main request. The same would be true for Claim 13 and Claim 9. Therefore Claims 6 and 13 as granted gave the instruction how to read Claims 1 and 9, respectively.

Essentially, the above arguments were also presented with respect to the first auxiliary request. Additionally, it was argued that the protection conferred by a European patent was defined by the wording of the claims, rather than only by a particular claim.

An applicant would have the right to word each claim in an independent or dependent form. Consequently, each claim could be considered as an independent claim, irrespective of whether it referred back to a previous claim.

Thus, Claim 1, as suggested in the first auxiliary request, should be regarded as having initially included two alternative statements, the one as defined in the claim as granted and the other derived from Claim 6 as granted, and the first of these alternatives as having then been deleted from the claim. This would have resulted in dropping/eliminating the narrower range of a molecular weight of not higher than 600, but maintaining the second range as provided by Claim 6. The same would also apply to Claim 8, which was derived from Claims 9 and 13 as granted.

In the course of the oral proceedings, the Appellant submitted a further set of claims as second auxiliary request. As in the first auxiliary request, claims 6 and 13 of the granted version were deleted, resulting in a consequential renumbering and adaptation of the wording of the previous Claims 7 to 12 (see sections V and III. (ii) , above). The amendments made in these claims were based on the detailed description of the crosslinking agents on pages 10 and 11 of the application (page 4 of the patent specification). The necessity of a further auxiliary request had become apparent to the Appellant only in view of the discussion during the oral proceedings.

The independent claims of this request read as follows:

"1. Use of a polyoxyalkylene polyol having an[.] oxypropylene group content of at least 70 % by weight, a terminal oxyethylene group content of at least 5 % by weight, a number of hydroxyl groups of from 2 to 8, hydroxyl value (X mgKOH/g) of from 5. to 38 and a total unsaturation degree (Y meq/g) of not more than 0.04, provided that when X is from 32.5 to 38, Y satisfies the formula Y =< 0.9/(X-10), for the manufacture of a polyurethane flexible foam, having an impact resilience of the core of at least 70 % (measured in accordance with JIS K 6401) and a resonant frequency of not higher than 3.5 Hz (measured in accordance with JAS 0 B407-82), said manufacture comprising reacting at least one high molecular weight polyol selected from the group consisting of said polyoxyalkylene polyol and a polymer-dispersed polyol containing said polyoxyalkylene polyol as the matrix, a crosslinking agent and a polyisocyanate compound in the presence of assisting agents such as a catalyst, a foaming agent and a foam stabilizer, wherein the crosslinking agent is a polyfunctional compound having two isocyanate reactive groups and having a molecular weight of not higher than 300 per isocyanate-reactive group or glycerol, diethanolamine, triethanolamine[,] t-butyltolylen[e]diamine, diethyltolylenediamine or chlorodiaminobenzene."

"8. Use of a polyoxyalkylene polyol having an oxypropylene group content of at least 70 % by weight, a terminal oxyethylene group content of at least 5 % by weight, a number of hydroxyl groups of from 2 to 8, a hydroxyl value (X mgKOH/g) of from 5 to 38 and a total unsaturation degree (Y meq/g) of not more than 0.07, with X and Y being in the following relation: Y =< 0.9/(X-10) with the proviso that the formula is applicable in a range of x > 10 for the manufacture of a polyurethane flexible foam, having an impact resilience of the core of at least 70 % (measured in accordance with JIS K 6401) and a resonant frequency of not higher than 3.5 Hz (measured in accordance with JAS 0 B407-82), said manufacture comprising reacting a polymer-dispersed polyol wherein the matrix is the above-mentioned polyoxyalkylene polyol and fine polymer particles are dispersed stably in the matrix, from 0.2 to 10 parts by weight, per 100 parts by weight of the polymer-dispersed polyol, of a crosslinking agent and an aromatic polyisocyanate in an amount of from 0.8 to 1.3 equivalent of the total amount of the polymer-dispersed polyol, the crosslinking agent and water when a foaming agent contains water, in the presence of a catalyst, a foaming agent and a foam stabilizer, wherein the crosslinking agent is a polyfunctional compound having two isocyanate reactive groups and having a molecular weight of not higher than 300 per isocyanate-reactive group or glycerol, diethanolamine, triethanolamine[,] t-butyltolylen[e]diamine, diethyltolylenediamine or chlorodiaminobenzene."

Claims 2 to 7 and 9 to 11 are dependent claims.

X. The additional arguments presented by the Respondents in the oral proceedings may be summarised as follows:

The second auxiliary request should not be admitted because of the late submission. The objections under Article 123(2) and (3) had been raised by the Opponents/Respondents a long time ago, so that any requests dealing therewith should have been provided earlier than only during the oral proceedings.

While it had been evident that the patent as granted had contained an error of some kind, the nature thereof had not been clear. Thus, the limitation of Claims 1 and 9 could have been fully intentional, whilst the adaptation of Claims 6 and 13 to the new wording of the independent claims might have been inadvertently omitted. Having regard to the statement of the invention on page 2 of the specification, the passage further explaining the crosslinking agent on page 4 of the specification (page 10 of the application) which originally referred only to an optional feature might have been erroneous. Moreover, the wording of Claims 1 and 9 as granted had been crystal clear and did not give rise to any questions as to whether it might have been erroneous. Therefore, there was no need for the reader to look in the file itself. Furthermore, the limitation of the molecular weight to 600 was not evidently wrong in view of D5 (column 8, lines 50 to 53) or D6.

Rule 88 EPC required that a correction in the patent specification had to be such that it was evident that nothing else would have been intended than that what was offered as the correction. This requirement was not fulfilled by the amendments in the claims of the main and the first auxiliary requests.

XI. In view of the claims according to the second auxiliary request, both Respondents maintained expressis verbis all their respective objections raised during the opposition proceedings, ie those of lack of novelty and inventive step and, in addition, the objection under Article 100(b) EPC, which had been raised by Respondent I and which had not yet been dealt with by the Opposition Division.

XII. The Appellant requested that the decision under appeal be set aside and that the patent be maintained on the basis of the set of claims submitted as first auxiliary request in the opposition proceedings (main request) or on the basis of the set of claims filed as second auxiliary request in those proceedings (first auxiliary request) or, in the alternative, that the case be remitted to the Opposition Division for further prosecution on the basis of Claims 1 to 11 submitted at the oral proceedings of 5 December 2002 (second auxiliary request).

The Respondents requested that the appeal be dismissed. Respondent I requested in the alternative that the case be remitted to the Opposition Division for further prosecution.