T 0122/84 (Metallic paint coating) of 29.7.1986

European Case Law Identifier: ECLI:EP:BA:1986:T012284.19860729
Date of decision: 29 July 1986
Case number: T 0122/84
Application number: 80103580.9
IPC class: C09D 5/38
Language of proceedings: DE
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Documentation of the appeal procedure can be found in the Register
Bibliographic information is available in: DE | EN | FR
Versions: OJ
Title of application: -
Applicant name: Hoechst
Opponent name: -
Board: 3.3.01
Headnote: If an opponent only claims that an invention cannot be carried out as required by Articles 83 and 100(b) EPC after the opposition period has expired, the submission may, applying the principle of examination by the European Patent Office of its own motion as set out in Article 114(1) EPC, be disregarded under Article 114(2) EPC. The decision of whether or not to take account of the submission is a matter for the discretion of the department concerned and requires no reasoned justification (Reasons for the Decision 9 - 14).
Relevant legal provisions:
European Patent Convention 1973 Art 100(b)
European Patent Convention 1973 Art 114
European Patent Convention 1973 Art 56
Keywords: Non-reproducibility as ground for opposition
Late submission
Examination by the European Patent Office of its own motion
Inventive step (accepted)
Stroke of luck


Cited decisions:
Citing decisions:
J 0005/11
J 0006/11
T 0476/88
T 0446/89
T 0669/89
T 0803/90
T 0931/91
T 0951/91
T 0011/92
T 0201/92
T 0986/93
T 0356/94
T 0891/94
T 0611/95
T 0476/98
T 0997/99
T 0496/02
T 2920/18
T 2295/19

Summary of Facts and Submissions

I. European patent No. 21 414 was granted on 23 June 1982 on the basis of European patent application No. 80 103 580.9 filed on 25 June 1980 claiming the priority of a previous application (DE 2 926 584) of 30 June 1979. It has nine claims, Claims 1 and 6 being as follows:

"1. A water-dilutable binder composition for the preparation of a metallic primer, characterised in that it contains as a base (a) a water-soluble condensation product derived from (a) saturated or unsaturated oil-free polyesters containing OH groups and prepared from at least one polycarboxylic acid and at least one polyhydric alcohol, (b) a polycarboxylic acid mixture derived from and containing trimellitic acid, (c) at least one epoxidised oil, (d) basic compounds, (b) a metal powder, (c) water-miscible solvents, (d) other pigments and/or dyestuffs (optional), (e) further conventional additives (optional), the weight ratio of solids in component (a) to those in (b) being between 50:50 and 90:10.

6. Use of the binder composition as claimed in one or more of Claims 1 to 5 in water-based paints to produce a two-layer metallic coating consisting of a prime coat and a top coat."

II. The opponents filed opposition to the European patent on 16 March 1983 based on various citations, requesting that it be revoked on grounds of lack of inventive step.

III. In a decision of 30 March 1984 the Opposition Division rejected the opposition, stating essentially that the citations gave no cause to question the novelty or inventiveness of the patent's subject-matter. While DD-PS 55 099 (1) did describe water-soluble binders based on polyesters obtained from dicarboxylic acids, monocarboxylic acids, polyhydric alcohols and epoxidised fatty acid esters, the binders of the contested patent additionally contained metal powder and were prepared without monocarboxylic acids. It was therefore unlikely that the known binders could be used for the metallic coating. Moreover DE-A-2 707 018 (2) was concerned with mixtures of the components (a), (b) and (c) in the contested patent which were not comparable to the condensation product in (1). Consequently, this teaching could not be combined in conjunction with that of (1).

IV. The opponents appealed against the decision on 23 May 1984, at the same time paying the appropriate fee. On 2 August 1984 they submitted a statement of grounds in which they maintained that the properties resulting from modification of a polyester with monocarboxylic acids were known to a skilled person and that to dispense with such modification involved no inventive step. Nor could it be said that inventiveness was involved in establishing that a known binder was suitable for metallic paints. Even if (2) described only mixtures, condensing binder components was nonetheless an expedient obvious to the paint specialist.

V. In their grounds for appeal the appellants (opponents) claimed for the first time that a skilled person could not reproduce the invention described in the contested patent using only the information contained therein. Example 1 described how the invention - a binder composition for making paints - was prepared using a condensation product said to be in everyday commercial use. Certain details of the properties of this starting product are given in the description. However, the opponents were unaware of any such condensation product in everyday commercial use. They had made a number of attempts to reproduce the invention with a product constituted as described and were submitting a report showing that the result was a solid resin unsuitable for use as a binder. In the absence of any identification of the condensation product in everyday commercial use, therefore, the alleged invention was not disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.

VI. The respondents argue that to dispense with modification of the polyesters using monocarboxylic acids was not an obvious procedure because among other things it affected both the physical drying process and rheological properties, particularly important in the case of metallic paints. Even were it possible to combine teachings of (1) and (2), the subject-matter of the contested patent would still not lack inventive step. It had been unexpected, indeed utterly surprising to find that it was possible using components (a) to (e) to produce a metallic primer which was not only easy to apply, gave an optimum metallic effect combined with excellent intercoat adhesion and weather- and light-resistance, but was also water-soluble at a pH value of about 7, dried rapidly and had good rheological properties for metallic primers.

VII. Answering the appeal the respondents (patent proprietors) did not deal with the objection that the invention could not be carried out.

VIII. At the oral proceedings on 29 July 1986 the appellants further claimed that component A of the binder composition of the contested patent was known from the patent proprietors' provisional leaflet "RESHYDROL VWA 1283" (3) issued in February 1979, in which it was recommended for use in a water-soluble stoving enamel. That was to be seen as an invitation to the skilled person to try the binder for two-layer metallic coatings. At these oral proceedings the appellants also returned to their objection that the invention could not be carried out. The results of the tests adequately and convincingly supported this objection and the Board of Appeal should now of its own motion establish whether the invention was disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art as required by Articles 83 and 100(b) EPC.

IX. The respondents deny that it was obvious to try the binder described in (3) for two-layer metallic coatings, claiming that the special characteristics of metallic paint make it impossible to pronounce in advance on the suitability therefor of the at least 50 to 60 water-dilutable binders on the market.

X. The appellants (opponents) request that the contested decision be set aside and the patent revoked. The respondents (patent proprietors) request that the appeal be dismissed.

Reasons for the Decision

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

2. The invention relates to a binder composition for two-layer metallic coatings. The parties agree that both the "wet-on-wet" method of applying the two-layer metallic coating and the binder composition used as described in the contested patent (page 1, lines 1-18) belong to the state of the art. There is also no dispute as to the fact that excellent quality metallic coatings can be obtained by this process and with the binder solution used hitherto. However, the conventional process is unsatisfactory in that the high proportion (about 85%) of solvent in the prime coat represents a considerable threat to the environment expensive to eliminate.

3. The technical problem was therefore to devise for the "wet-on-wet" process non-polluting primers which maintain the high quality of the metallic coating hitherto achieved. This problem is solved according to the contested patent by using a water-dilutable binder composition to make metallic primers having the constituents detailed in the claim. The Board accepts that this problem has been solved. As Example 1 demonstrates, only minor quantities of water-soluble organic solvents are required to prepare the primer, the paints do not run when sprayed onto a surface and they dry quickly, the result being a flawless high-gloss metallic coating.

4. None of the citations describes a binder composition having all the characteristics of the binder composition as claimed in Claim 1. The closest citation (3) really describes only component A of the binder composition of the contested patent. The question of the novelty of the subject-matter of the contested patent need not be gone into further here since this is not in dispute.

5. What therefore has to be established is whether a skilled person faced with the problem of producing non-polluting primers of equivalent high quality would have found it obvious to suggest using the water-dilutable binder compositions of the contested patent. As already mentioned, the industry has, through the cited leaflet (3), been made aware of and offered a water-based binder which indisputably falls within the definition of component A of the primer described in the contested patent. According to this leaflet, (r) Reshydrol VWA 1283 is a hydrosol which contains no emulsifier, is completely soluble in water at a pH of about 8 and includes no organic solvents. It readily absorbs non-electrolytic, inert pigments and fillers, is hardened by heat and is recommended for use as sole binder in the manufacture of stoving enamels. This information is not sufficient for a skilled person to realise that the binder can be used to make a metallic primer. The Board was convinced by the respondent's statement at the oral proceedings that a paint of this kind has to fulfil a whole series of conditions to be suitable for the "wet-on-wet" process and to give the high-quality metallic coating the invention set out to achieve. A particularly crucial factor here is the paint's rheological properties, which must be such as to permit a perfect application without running on vertical surfaces. At the same time, the paint must be able to be applied as a relatively thin, quick-drying coat so as to ensure that the metal particles it contains are fixed rapidly and parallel to the base, since only then will an optimum metallic gloss be obtained. Finally, the coat needs to adhere well to the still moist prime coating, which must not merge into it. In view of these very specific requirements - which have not been exhaustively listed - and the ambitious aim of maintaining the acknowledged high standard of metallic coating, the somewhat vague reference in (3) to the use of the commercial product Reshydrol with its high pigment absorbency for stoving enamels cannot be taken as a suggestion that this binder be tested as to its suitability for metallic primers for two-layer application. The Board is aware that, lacking as he did definite information as to the relationship between the chemical structure of such paints and the properties required of them, a skilled person would have been obliged to experiment. It also has to be conceded that one aspect of the problem, namely the ecological acceptability of the primers, would in fact have suggested that water be substituted for polluting organic solvents. Indeed it emerged in the course of oral proceedings that the industry has tried, albeit in vain, to devise a solution along these very lines. Precisely because of that failure a skilled person would not have seen the proposal to use yet another water-based binder, accompanied by the barest reference to its suitability as a stoving enamel with high pigment absorbency, as a reason for testing it for the metallic paint in question. Moreover, as the parties agree, at least 50 to 60 commercial products in everyday use were already available for the purpose, so that with no prospect of success in view there was no reason to give preference to Reshydrol in particular. Also, random experimentation would have thrown up an impossible number of chemical modifications to known water-based binders. A stroke of luck was, therefore, certainly needed in order to pick out from the large number of alternatives the very binder designated as component A in the contested patent for use in the metallic primer. Indeed, the search can only be regarded as a lottery.

6. Since at the oral proceedings neither the parties nor the Board attached any great importance to the other citations and accordingly made no further reference to them, they require no discussion. It must therefore be concluded that the water- dilutable binder composition as claimed in Claim 1 of the contested patent was not obvious to a person skilled in the art and hence involved an inventive step.

7. Despite its dependence on the substance claim, Claim 6, which is use-directed, must be viewed as a parallel claim because of its different category. It claims the use of the metallic primer defined in Claim 1 to produce a two-layer metallic coating consisting of a prime coat and a top coat, in other words the complete "wet-on-wet" process. Since production of the metallic primer already involves an inventive step and the two-layer process is unthinkable without the paint, the process is patentable along with the subject-matter of Claim 1.

8. The same conclusions must also apply to Claims 2 to 5 and 7 to 9, which are dependent on Claims 1 and 6 respectively and are concerned with specific, particularly suitable embodiments.

9. Since therefore the grounds for opposition as filed do not prejudice maintenance of the European patent (cf. Article 102 EPC), the question is whether the contested patent must be revoked on the grounds - only advanced by the opponents in their appeal - that the invention cannot be carried out as required by Articles 83 and 100(b) EPC. The answer depends first of all upon whether the Board of Appeal is obliged to clarify the question of the invention's reproducibility under Article 114(1) EPC "Examination by the European Patent Office of its own motion" or whether it can disregard the opponents' submission under Article 114(2).

10.1 The principle of "examination by the European Patent Office of its own motion" (Article 114(1) EPC) continues to apply even after a patent has been granted, in proceedings before the Opposition Division and the Board of Appeal. This is made clear both by the terms of that provision and by Article 102(1) to (3) EPC, which stipulates that decisions concerning oppositions hinge upon the Opposition Division's opinion with regard to patentability (Article 52 et seq. EPC) and other requirements of the Convention. In forming its opinion it is not in any way bound by the facts, evidence and arguments provided by the parties (cf. Article 114(1) EPC). The same applies, according to Article 111(1), second sentence, and Rule 66(1) EPC to appeal proceedings.

10.2 That the principle of examination by the Office of its own motion even after a patent has been granted, i.e., in opposition applies proceedings before the departments of first and second instance, is confirmed and elucidated in the travaux préparatoires to the EPC. Article 114 originated in a provision proposed specifically (by the Chairman of the EC Patent Working Party on 29 May 1961) with appeal proceedings in mind and identical in its wording to Article 114 as it now stands. The comments made on this proposal on 28 July 1961 include the statement that a patent must be examined in its entirety irrespective of the facts, evidence and arguments advanced by the parties and the relief sought. In a second paragraph identical to Article 114(2) EPC it was proposed that the Board of Appeal be entitled to disregard facts not submitted in good time, the purpose being "to prevent appeal proceedings from being dragged out unnecessarily by malicious or negligent appellants". This proposal was discussed and accepted by the Working Party (EC Doc. IV/6514/61 of 13 November 1961, p. 4). The minutes of the meeting state among other things that the Board of Appeal may make up its own mind whether or not to take account of new facts (as referred to in paragraph 2) and accordingly is not obliged to incorporate such facts in its decision. This idea was also taken over by the Luxembourg Inter-Governmental Conference for a corresponding Article 113 in its "First Preliminary Draft" of the EPC of 1970 (see "Reports" thereon, p. 25, point 137). Paragraph 2 "serves to prevent appeal proceedings being excessively delayed by negligent or intentionally dilatory applicants".

10.3 The principle of examination by the Office of its own motion during opposition proceedings, i.e. even after a patent has been granted, is explicitly confirmed in the travaux préparatoires (BR/87/71 dated 28 February 1971). An Article 101b relating to opposition proceedings, whose text corresponded to the above- mentioned Article 113 for appeal proceedings, was included in the "Second Preliminary Draft" of the EPC of 1971 (see also "Reports" thereon, p. 31, point 68). Paragraph 2 of that article reads: "The Opposition Division may disregard fresh facts or evidence submitted by the parties concerned".

10.4 The provisions relating to examination by the European Patent Office of its own motion in examination, opposition and appeal proceedings were then combined in Article 113 of the draft EPC of 1972. The Office's discretion in deciding whether or not to disregard new facts and evidence was no longer linked to specific omissions such as failure to observe time limits for filing statements of grounds or comments, and instead the unspecific egal term "not submitted in due time" was adopted. The new provision became Article 114 EPC "Examination by the European Patent Office of its own motion".

11. The interpretation of Article 114 EPC poses the question of the relation paragraphs 1 and 2 bear to one another. Paragraph 1 requires the European Patent Office to examine the facts of its own motion, while paragraph 2 allows the Office to disregard facts or evidence not submitted in due time. This problem was already recognised in the travaux préparatoires (see BR/12/69 dated 18 December 1969, p. 23, point 50, and BR/125/71 dated 7 July 1971, p. 33, point 66 and p. 35, point 70). However, a solution seen as not conflicting with the principle of examination by the Office of its own motion was that of leaving the department concerned to decide whether facts or evidence not submitted in due time should be examined instead of ruling out that possibility - an alternative also considered. In adopting this solution it was assumed that sparing use would be made of the option of disregarding facts or evidence, whose purpose was to prevent the parties from improperly dragging out opposition proceedings (see BR/12/69, loc. cit.).

12. In the case of an opponent, the Board of Appeal considers that facts or evidence have not been submitted in due time in the meaning of Article 114(2) EPC if grounds for opposition under Article 100 EPC originally not mentioned at all are submitted for the first time after the opposition period has expired. This is particularly obvious if - as in the present case - the grounds for opposition under Article 100(b) EPC are submitted only after the opponents have failed in their original opposition before the department of first instance. Where opposition documents filed subsequently not only contain additions to, and evidence in respect of, those filed originally, but incorporate changes or further reasons for revocation, it would definitely be the Board's view that they have not been submitted in due time under Article 114(2) EPC. Otherwise, the obligation under Articles 99 and 100 EPC to submit grounds for opposition within the opposition period would be meaningless. This is also confirmed by the predecessor to Article 114(2) EPC, namely Article 101b of the Second Preliminary Draft of the EPC dated 1971. This leaves it to the Opposition Division to decide whether it will disregard fresh facts or evidence not included in the statement of grounds for opposition.

13. A discretionary decision carries with it an unquestionable obligation properly to exercise that discretion. However, the European Patent Office does not owe the parties any explanation concerning its examination of the facts of its own motion and therefore need not justify its decision if facts or evidence are not submitted in due time. On the other hand, material which has been submitted in due time or has been introduced as a result of an examination by the Office of its own motion must, where it is considered relevant by the European Patent Office or by one of the parties, be dealt with in the Reasons for the Decision, either by the Opposition Division under Rule 68(2) or by the Board of Appeal under Rule 66(1)(g) EPC. Misuse of the discretion allowed by Article 114(2) EPC will be recognisable even if no reasons are given for the decision. In line with Article 114(1) and (2) EPC, misuse is considered to have taken place only if (a) it is clearly proven that facts or evidence were not submitted in due time; if (b) the patent proprietors have already had adequate opportunity to present their comments in accordance with Article 113(1) EPC or can still be given this opportunity without unduly delaying the proceedings; and if (c) the decision in question obviously ought not to be taken when the facts or evidence submitted late are taken into account.

14.1 While according to Article 114(2) EPC equal treament must in principle be accorded to the most widely differing grounds for opposition not submitted in due time, such as a new state of the art (Article 100(a) EPC), non-reproducibility of the invention (Article 100(b) EPC) or inadmissible additions (Article 100(c) EPC), it is clear from the above that in practice the situation is liable to vary. It will often not take long to grasp the substance of a new citation not submitted in due time but not over-long and to determine its relevance to a decision. An opponent's assertion that the contested patent "extends ... beyond the content of the earlier application as filed" within the meaning of Articles 123(2) and 100(c) EPC can always be checked quickly by reference to the file. The Office must therefore take it into account of its own motion when applying Article 102(1) to (3) EPC, as in the case of decision T 285/84 of 29 April 1986 (unpublished).

14.2 If an opponent does not make the claim that the invention cannot be carried out in accordance with Articles 83 and 100(b) EPC in due time, even the presentation of test results will not as a rule suffice as definitive evidence of the validity of the argument against maintaining the patent. This is especially true if, as in the present case, the patent specification cites examples of how the invention can be carried out. With chemical processes in particular, the desired result is often not obtained under all the conditions apparently possible in the light of the description. Even a well-intentioned opponent may, when reproducing a chemical process, meet with failures which can only be overcome by additional experiments that he could reasonably be expected to perform. The revocation of a process patent in the field of chemistry solely on the grounds that it cannot be carried out can hardly be justified without the patent proprietor having been given an opportunity to check the opponent's experiments and to confirm by means of new tests of his own that the invention is in fact reproducible. If the objection as to non-reproducibility is submitted late, it is natural in opposition proceedings for the Opposition Division to consider it more desirable to conclude the proceedings rapidly rather than embarking on a lengthy process of fact-finding of uncertain outcome. In contexts such as this, examination by the Office of its own motion within the meaning of Article 114 EPC is circumscribed by other procedural principles deriving in the main from the nature of opposition proceedings as a summary, hence rapid, procedure, from the general principle that proceedings should be kept as brief as possible, or from the fact that the burden of proof lies with the opponent. A situation of the latter kind arose in the case of decision T 219/83 "Zeolites/BASF" (OJ EPO 7/1986, p. 211). Here the opponents questioned the existence of an inventive step, arguing that the results achieved by the invention were not surprising since they were already achievable by conventional methods. The Board was unable on the basis of its own expertise to concur with either this assertion or the contrary standpoint of the patent proprietors. As the Board did not see itself able to establish the relevant facts through an examination of its own motion, the patent proprietors were given the benefit of the doubt (loc. cit., Headnote I and Reasons 12).

14.3 Moreover, it is not possible here either to invoke the reasons which, where documents are filed late, make the delay appear excusable. Experiments which cast doubt on whether an invention can be carried out are not the result of chance but performed with a specific purpose in mind. Moreover, an opponent must conduct such experiments before filing his opposition and not wait until the opposition proceedings show that the grounds he has submitted under Article 100(a) EPC - thus primarily the assessment of lack of inventive step - do not carry the necessary weight.

15. In the light of these general considerations and particularly of those concerning the inability of an invention to be carried out, the Board concludes as follows: If an opponent only claims that an invention cannot be carried out as required by Articles 83 and 100(b) EPC after the opposition period has expired, the submission may, applying the principle of examination by the European Patent Office of its own motion as set out in Article 114(1) EPC, be disregarded under Article 114(2) EPC. The decision of whether or not to take account of the submission is a matter for the discretion of the department concerned and requires no reasoned justification. The Board therefore chooses to disregard the opponents' assertion that the invention cannot be carried out contained in their grounds for appeal.

16. The Board has considered referring the legal questions discussed above to the Enlarged Board of Appeal under Article 112 EPC. However, it felt that such a step was premature for the time being and that interested parties should first be given an opportunity to comment on the decision. It also considers it desirable to await the decisions of other Boards of Appeal in identical and similar cases.

17. The Board has also compared its finding, in the light only of European law, with the legal position in the Federal Republic of Germany. This would seem justified because this particular Contracting State has a similar form of opposition procedure. The Board found that its conclusions accord with the principles laid down by the Federal Court of Justice in its "Gleichstromfern speisung" decision of 2 June 1977 (GRUR 1978, p. 99, Bl. f. PMZ 1977, p. 277). Also relevant is Schulte, Kommentar zum deutschen Patentgesetz, 3rd edition, 59, points 56, 57 and 61, and other decisions cited therein.

18. Furthermore the Board has reviewed its own decisions on similar matters of procedure and found there to be no inconsistencies between them and the present decision.

18.1 In Decision T 01/80 "Carbonless copying paper" of 6 April 1981 (OJ EPO 7/1981, p. 206) the results of experiments are regarded as having been submitted in due time within the meaning of Article 114(2) EPC if those results justify a restatement of the problem, a possibility still open in appeal proceedings. In Decision T 129/82 of 14 February 1984 (unpublished) the Board took account of experiments as having been submitted in due time although they had only been filed as a result of an unfavourable communication from the Board.

18.2 Decision T 183/83 of 13 December 1984 (unpublished) takes account of the results of experiments which the opponents only submitted with their statement of grounds for appeal and which were intended to demonstrate that the invention could not be carried out as required by Article 100(b) EPC. This case differs from the present one in two respects. Firstly the relevant ground for opposition was stated when the opposition was filed, albeit without experimental evidence to back it. Secondly the results of experiments - only submitted when the appeal was under way - were clearly not such as to cast doubt on the reproducibility of the invention described in the contested patent. The Board was able to assess them without delaying the proceedings at all, which benefited the patent proprietors. The opponents, whose case was rejected, were given every opportunity to present their comments.

18.3 In Decision T 273/84 of 21 March 1986 (OJ EPO 10/1986, p. 346) the Board introduced into the proceedings as indispensable one of three citations which had not been submitted in due time. There was no question of granting the patent proprietors the opportunity to present their comments in full, if only because the case was referred back to the department of first instance for re- examination. Decision T 271/84 of 18 March 1986 (to be published), draws attention to the importance of weighing the disadvantages of a delay in the proceedings against the relevance of the submission.

18.4 All these decisions involve the exercise of the discretion allowed by Article 114(2) EPC. They also demonstrate that there is no need to justify the exercise of discretion to the parties.


For these reasons, it is decided that:

The appeal is dismissed.

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