T 0093/89 (Polyvinyl ester dispersion) of 15.11.1990

European Case Law Identifier: ECLI:EP:BA:1990:T009389.19901115
Date of decision: 15 November 1990
Case number: T 0093/89
Application number: 83106782.2
IPC class: C08F 18/06
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: Henkel
Board: 3.3.03
Headnote: 1. If an alleged prior public use is not adequately substantiated, it is immaterial and, if not submitted in due time, may be disregarded under Article 114(2) EPC.
2. Prior public use is only adequately substantiated if specific details are given of what was made available to the public where, when, how and by whom.
3. If the composition of a commercially available product can be established only by a chemical analysis, the ingredients of the product have not been made available to the public unless there was reason for experts to investigate it.
Relevant legal provisions:
European Patent Convention 1973 Art 54
European Patent Convention 1973 Art 56
Keywords: Novelty (yes)
Prior public use not substantiated and not claimed in due time
Prior public use of a commercially available chemical
Commercially available product, grounds for chemical analysis
Inventive step (confirmed)


Cited decisions:
Citing decisions:
G 0001/92
T 0595/89
T 0953/90
T 0221/91
T 0441/91
T 0083/92
T 0097/92
T 0952/92
T 1002/92
T 0169/93
T 0097/94
T 0301/94
T 0575/94
T 0003/95
T 0633/95
T 1069/96
T 0037/98
T 0176/98
T 0240/99
T 0526/99
T 0864/99
T 0947/99
T 0837/02
T 1134/06
T 2043/07

Summary of Facts and Submissions

I. European Patent No. 100 892 with three claims was granted on 12 March 1986 in response to European patent application No. 83 106 782.2, filed on 11 July 1983 and claiming priority from a previous application of 16 July 1982 (DE 3 226 681).

Claim 1 of the first set of claims for the Contracting States CH, DE, GB and LI was worded as follows:

"An aqueous polyvinyl ester dispersion having a solids content of between 35 and 65 weight%, characterised in that between 3 and 60 weight% of the dispersed particles have a diameter of below 1 µm and consist of an amount between 95 and 100 weight% of polyvinyl acetate or a vinyl acetate copolymer and of an amount between 0 and 5 weight% of native starch; between 40 and 97 weight% of the dispersed particles have a diameter of between 1 and 40 µm and consist of an amount between 20 and 95 weight% of polyvinyl acetate or a vinyl acetate copolymer and of an amount between 5 and 80 weight% of native starch; and the dispersion contains between 3 and 12 weight%, relative to the total amount of the dispersed particles, of polyvinyl alcohol."

Claim 1 of the second set of claims for the Contracting State AT was formulated as a process for the manufacture of an aqueous polyvinyl ester dispersion having a solids content of between 35 and 65 weight%.

II. On 11 December 1986 the opponents filed opposition against the grant of the European patent and requested that it be revoked on the grounds of a lack of inventive step. In support of their submission the opponents cited the following documents

(1) German patent application S 39 673 IV a/22i

(2) US-A-2 996 462

as well as several other documents referred to later.

III. By a decision dated 23 November 1988, posted on 19 December 1988, the Opposition Division decided that the patent could be maintained as amended. ...

IV. The opponent's (appellants), having lost their case, appealed against the Opposition Division's decision on 4 February 1989, at the same time paying the prescribed fee, and filed a statement of grounds on 14 April 1989. ...

V. In their subsequent submissions and particularly in the oral proceedings on 15 November 1990 the appellants claimed prior public use by reason of their own commercially available products and submitted a statutory declaration to that effect; this claim had first been hinted at in their submission of 15 March 1988, over 15 months after expiry of the period for opposition. ...

VI. ... The respondents contested the existence of prior public use, referring to the results of their own analyses.

VII. The appellants request that the contested decision be set aside and the patent revoked.

The respondents 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 contested patent relates to an aqueous polyvinyl ester dispersion, a process for its preparation and its use. A dispersion of the same kind is used in the process of (1), which the Board regards as the closest prior art and which describes a process for bonding wooden floors onto concrete beds using a glue consisting of between 33 and 95% polyvinyl acetate dispersion, between 2.5 and 33% polyvinyl alcohol solution and between 2.5 and 33% fillers and auxiliaries (Claim 1). Numerous finely ground industrial meals as well as organic and inorganic products are quoted as being suitable fillers; useful auxiliaries are softeners, precipitating agents, and organic and inorganic compounds which are intended to impart specific properties to the parquet glue (p. 2, lines 45 - 76). Although the final bond strength of the bonded joints is very high with this parquet glue, and although it enables thin parquet mosaic to be glued onto concrete (p. 2, lines 77 - 85), this high level of strength is achieved only after 1 to 4 hours, which is a disadvantage for the use of the adhesive in mechanical operations.

The problem on which the contested patent is based can therefore be seen as the provision of an aqueous polyvinyl ester dispersion with which a high bonding strength is achieved in a shorter space of time without impairing the final bond strength.

To solve this problem, the contested patent suggests (in simplified terms) an aqueous polyvinyl ester dispersion having a solids content of between 35 and 65 weight%, wherein the dispersed particles, having a bimodal size distribution, consist of polyvinyl acetate and native starch, and contain also between 3 and 12 weight% of polyvinyl alcohol with specific characteristics (ester number and viscosity).

4. After examining the citations referred to above, the Board has come to the conclusion that the proposed solution claimed is novel with respect to the prior art of these citations. As novelty is undisputed in this respect, there is no need for further explanations.

5. There remains the question of whether the aqueous polyvinyl ester dispersion of Claim 1 in the first set of claims is based on an inventive step. ...

5.4 To summarise, documents (1) and (2) cannot lead the skilled person to a solution of the aforementioned problem; the subject- matter of the contested patent as set out in Claim 1 therefore involves an inventive step.

8. The appellants claim prior public use, i.e. that in advance of the priority date of the patent they were marketing polyvinyl acetate dispersion adhesives containing (native) starch as defined by the contested patent. The Board decided to disregard that claim on the grounds that it was not submitted in due time (Article 114(2) EPC).

The appellants made this claim without further substantiation for the first time in their pleadings of 14 March 1988, i.e. over 15 months after expiry of the opposition period. According to the record of the oral proceedings before the Opposition Division, the appellants did not repeat their claim at the oral proceedings on 23 November 1988; the contested decision does not therefore discuss the claim. Even in their statement of grounds of 12 April 1989 the appellants do not devote a single word to the alleged prior public use. Only in their pleadings of 29 August 1989 do they return, in the appeal proceedings, to the prior public use hinted at in their pleadings of 14 March 1988, maintaining that they referred to it in the oral proceedings before the Opposition Division, but that the public nature of this prior use was not discussed. Anyone who claims a prior public use, merely in passing, after expiry of the opposition period and who fails to provide further details until well into the appeal proceedings must be deemed not to have submitted in due time (Article 114(2) EPC), especially where the prior use is by the appellants themselves, as in the present case.

If a submission is not made in due time, according to the established practice of the Boards of Appeal (T 156/84, OJ EPO 1988, 372) it can be disregarded only if the Board considers its substance immaterial. The Board came to this conclusion on the basis of the oral proceedings and, in particular, the appellants' behaviour in the opposition and appeal proceedings.

8.1 The prior use claimed is use by the appellants themselves. If, by its nature, this use had actually been a bar to the grant of the European patent in question, in the normal course of events the appellants could have been expected to base their opposition on these grounds from the outset. The fact that the appellants merely mentioned prior use by themselves in the proceedings at first instance without further substantiation and, even in the appeal proceedings, did not refer to it in their statement of grounds, leads the Board to conclude that they clearly did not attach great importance to this alleged use; otherwise they would have claimed use by themselves when filing opposition.

The Board's conclusion is reinforced by the incompleteness of the submission claiming prior use. Prior public use is adequately substantiated only if sufficiently specific details are given of what was made available to the public where, when, how and by whom (T 300/86 dated 28 August 1989, point 2.7, quoted in the 1989 annual report, supplement to OJ EPO 6/1990, p. 25; T 194/86 dated 17 May 1988, point 2, Rechtsprechungskartei Gewerblicher Rechtsschutz "EPU 54 No. 73"). An adequate submission must therefore contain details of the manner, place and time of the alleged use with a specific description of the subject-matter and particulars of its availability to the public with the possibility of subsequent use by other experts.

Even the indication that the period of prior use was "as long ago as 1979" is so vague that it does not qualify as a clear statement of the time of the prior use.

8.2 Furthermore, there are no specific details to support the allegation that the claimed prior use was public. The appellants merely submitted that, on the basis of the closest prior art, i.e. reference (1), it must have been obvious to the skilled person that the appellants' product "Ponal express" should be investigated, in which case the skilled person would have found that it contains substantial quantities of both polyvinyl alcohol and native starch. By this submission the appellants make it clear that they did not themselves inform the public of the composition of their product; that is only natural as, to protect its own commercial interests, a business enterprise is not in the habit of divulging such information to its competitors. A skilled person cannot tell the composition of the product itself, an adhesive, just by looking at it; a chemical analysis would be required for that purpose, but in the Board's view there were no grounds for such an analysis.

The mere fact that a company launches a new commercially available product is not necessarily sufficient reason for its competitors to test the product to determine its ingredients. There is no evidence to suggest that companies test all their competitors' new products, at least as far as the chemical composition of new commercially available products is concerned. There would need to be a specific reason to justify such an analysis, which after all costs money. In the present case the Board can see no such reason. Of course competitors are interested in comparing new products with their own, but a chemical analysis is not absolutely necessary for this purpose. Initially it is sufficient to establish the properties of the new product, in this case a new adhesive whose properties can be determined without analysis. The appellants did not submit that their new commercially available product "Ponal express" had such special properties that a competitor would have had reason to carry out a chemical analysis. The Board does not therefore see the mere appearance of a new commercially available product as grounds for a chemical analysis.

According to the appellants, reference (1), as the closest prior art, was an obvious reason for the skilled person to investigate the appellants' product. In the Board's opinion, this train of thought is based on an unrealistic view of the way competitors behave. Competitors look at the market from the commercial angle, not with patent specifications clutched in their hands. Only when a product is of interest because of its special properties and is then tested and analysed on those grounds might attention turn to the prior art to discover whether imitation is allowed.

Even if an expert had analysed the appellants' commercially available product, he would by no means have been certain of finding native starch as an ingredient since, as the appellants themselves have testified, their product was made partly with and partly without native starch. This means that a chemical analysis of the commercially available product would have provided evidence of the presence of starch only by chance, and this might well be the logical explanation for the absence of starch in the analytical results obtained by the respondents (cf. pleadings of 14 February 1990), who tested samples of the commercially available product manufactured prior to 1979 and now.

8.3 For all these reasons the alleged prior use is of no significance for the contested patent; since the prior use claim was not submitted in due time, there is therefore nothing to prevent it from being disregarded, and so it is not taken into account when assessing the patentability of the contested patent.


For these reasons it is decided that:

The appeal is dismissed.

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