T 0014/97 11-02-2000

Summary of Facts and Submissions

I. The appellant (opponent) lodged an appeal against the decision of the Opposition Division rejecting the opposition against the patent No. 0 431 439.

II. An Opposition was filed against the grant of claims 1 to 3 of the patent and based on Article 100(a) EPC. The Opposition Division held that the grounds for opposition cited in the Article 100(a) EPC did not prejudice the maintenance of the patent as granted.

III. The following documents were cited in the notice of opposition:

D1: DE-A 35 35 272;

D2: US-A 4 749 613;

D3: US-A 4 158 557.

IV. The appellant requested that the decision under appeal be set aside and the patent revoked because the method claimed in claims 1 to 3 of the patent did not involve an inventive step with regard to the prior art as disclosed in documents D1 and D3.

V. The respondent (proprietor) requested that the appeal be dismissed.

VI. In the Notice of Appeal the appellant requested oral proceedings as an auxiliary request.

With letter of 13 May 1997 the respondent requested oral proceedings in the event that the Board of Appeal is not prepared to reject the appeal without oral proceedings.

With telefax dated 5 January 2000 the Board communicated its intention to summon the parties to attend oral proceedings on 11 April 2000.

With a letter of 14 January 2000, received on 18. January 2000, the appellant communicated to the Board that he will not attend the oral proceedings scheduled for 11 April 2000 and asked for a decision on the file as it stands.

With a communication dated 1 February 2000 the parties were informed of the cancellation of the oral proceedings.

VII. The wording of independent claim 1 of the patent in suit reads as follows:

Method of manufacturing glass fiber mats (19), composed of a non-oriented fiber layer (13) shaked down onto a conveyor means (10) and a layer of bundles of uni-directional fibers (15), which fiber layers are laminated one upon the other on the conveyor means (10,11) and are needled to form the glass fiber mat, characterized in that,

the bundles (12) of non-oriented glass fibers first are shaked down onto conveyor means (10) to form the non-oriented fiber layer (13) which is dried thereafter, that the bundles (15) of uni-directional fibers are supplied onto the dried non-oriented fiber layer (13) to laminate a uni-directional fiber layer onto the dried non-oriented fiber layer (13), the bundles of uni-directional fibers (15) being guided in parallel to each other at regular intervals in widthwise direction of the conveyor means (10,11), and that the thus formed laminate of uni-directional and non-oriented fiber layers is needled to form the glass fiber mat (19).

VIII. The opposition division rejected the opposition particularly for the following reasons:

Document D1, which was regarded as the closest prior art, describes, cf. example 2, a process wherein oriented fibres were supplied onto a non-oriented glass fibre mat to form a laminate and the laminate was thereafter needled.

The essential difference between the subject-matter of claim 1 and the method described in example 2 of D1 was seen in the provision of a drying step after shaking down the bundles of non-oriented fibers but before the uni-directional fibers are supplied.

The method claimed in claim 1 of the patent in suit comprising said feature was found not to be obvious, because, firstly, it had been recognized that blown air in the drying step would disturb the orientation of the unidirectional oriented fibers which would result in a loss of quality of the final fiber, and, secondly, the skilled person would not find any suggestion in the prior art documents whereby the additional drying step should be provided to avoid the problem caused by the disturbance of the orientation, because document D2 does not describe a method comprising a drying step and document D3 does not use uni-directional oriented fibers, the orientation of which may be disturbed.

IX. The appellant argued essentially as follows:

Document D1, which represents the closest prior art, describes, as example 2, a process wherein uni-directional fibres are supplied onto a non-oriented, probably dry, glass fibre mat. The claimed process differs from the known process by the implementation of the drying step.

However, if wet non-oriented fibres were used, then the laminate would have to be dried, as known from document D3. It was emphasized that the person skilled in the art knew about the hydrolysis and foam forming problems arising from the use of wet fibers and, accordingly, the necessity of drying the fibers.

Thus, when starting from the method described in D1, example 2, and provided that wet fibers were used, then there were only two options to implement a drying step, namely option (a) before and option (b) after the supply of the oriented fibres. The person skilled in the art would select the first mentioned option a), because this would be easier and the person skilled in the art would take into consideration that the orientation of the oriented fibres might be disturbed by the hot air applied for drying.

X. The proprietor referred to the arguments presented in the decision under appeal.

He further noted that the cited documents were silent about any reasons for drying and any drawbacks thereof and that the hydrolysis and foam forming problems were mentioned only in the description of the patent in suit.

Furthermore, the two alternatives (a) and (b) mentioned by the appellant were not the only ones, as could be seen from the state of the art shown in Figure 13 of the patent in suit, which described the option (b) but with the deposition of the fibers in reverse order, and documents D1 and D2, which described methods without any drying step.

The assertions of the appellant were thus the result of an inadmissible ex post facto analysis.