T 2121/19 08-03-2023

1. Article 123(2) EPC

Features 1.4a and 1.4b were added to claim 1 of the patent as granted during opposition proceedings.

The opponent argued that these features of claim 1 now included undisclosed embodiments wherein there was no spacing between the lamellas. The claimed subject-matter thus related to an undisclosed intermediate generalisation.

In assessing the question of added subject-matter it is established case law at the EPO Boards of Appeal that amendments can only be made within the limits of what a skilled person would derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing from the application as originally filed (Case Law of the Boards of Appeal, 10th edition, 2022, II.E.1.3.1.).

In the present case, the skilled person would understand that the lamellas were not arranged perfectly regularly as shown in Fig. 4 but rather somewhat erratically, as explained in the application p. 11, 2**(nd) paragraph. This is also what the skilled person would expect as the flow through the nozzle is unlikely to be perfectly laminar.

The skilled person would therefore realise that a spacing of zero was indeed included in the disclosure of the application because it was inevitable from the manufacturing process that some lamellas would touch. Hence, the skilled person would consider that zero spacing was included in the disclosure of the application as originally filed.

It is correct that Figure 4 shows lamellas which are all spaced apart from each other. However, as set out on page 11, 2**(nd) paragraph, this figure represents an idealised and simplified illustration of the diffusion barrier layer. Moreover, the 3**(rd) paragraph on page 11, to which the appellant referred, is a description of Figure 4 and hence also describes an idealised situation and not the actual distribution of the lamellas within the diffusion barrier layer.

Hence, the subject-matter of claim 1 does not extend beyond the content of the application as originally filed.

2. Article 84 EPC

Features 1.4a) and 1.4b) were taken from the description and may thus be examined for clarity (G 3/14).

It is correct that in feature 1.4a) the term "plane" is used and in feature 1.4b) the term "sheet plane" is used. The skilled person reading the claim would however immediately realise that these refer to the same item. Thus, there is no lack of clarity introduced by the modifications in this respect.

The appellant further argued that configurations with lamellas spaced in such a way that they did not provide a barrier effect were covered by the amended claim which would stand in contradiction with the description as originally filed p. 11, first paragraph which requires diffusion resistance or rather diffusion impermeability.

The Board does not find this convincing. Feature 1.3 requires a diffusion-resistant diffusion barrier portion forming at least partly a diffusion barrier. Thus, any embodiment of the diffusion barrier portion where the lamellas did not act as a diffusion barrier would not fall under the scope of the claim. Hence, there is no contradiction between claim and description.

Moreover, the objection against the term "diffusion resistance" is not due to the amendment because feature 1.3 of the granted claim already referred to "diffusion-resistant". Any possible lack of clarity was thus already in the granted claim and cannot be examined.

Claim 1 therefore fulfills the requirements of Article 84 EPC.

3. Sufficiency of disclosure

The patent discloses the materials used and the process of extruding through a slit (paragraph [0062]). It does not give temperatures, speeds, or exact material compositions. The skilled person however knows what result is to be achieved and has the starting points. They would therefore use routine trial and error to arrive at the result required. Such routine experimentation is well within the capabilities of the skilled person.

The invention is therefore sufficiently disclosed.

4. Novelty with respect to D1 and D2

D1 discloses a spacer profile where a substance which usually contains lamellas is added to the polymer material, e.g. talc ("Talkum") or mica ("Glimmer"), see D1, col. 3, l. 40 to 45. D2 also discloses a spacer profile in which flaky ("plattchenförmig") particles are added. These particles can be made of wollastonite, mica or talc (see D2, p. 3, l. 25 to 27).

However neither D1 nor D2 give any details of the process used to extrude the profiles. There is no mention, as in the attacked patent, paragraph [0062], of an extrusion nozzle in the form of a slit which generates a laminar flow. Therefore, despite the similar starting materials used in D1 and D2, there is no evidence that the lamellas are orientated as claimed, consequently features 1.4a and 1.4b are not known from D1 or D2.

The subject-matter of claim 1 is thus new with respect to D1 and D2.

5. Inventive step

5.1 D1 or D2 in combination with the knowledge of the skilled person

The subject-matter of claim 1 differs from the disclosure of D1 and D2 by features 1.4a and 1.4b.

The problem to be solved is to improve the barrier properties of the spacer.

The appellant argued that the skilled person would from their general knowledge extrude the spacer profile as known from D1 or D2 in such a way as to arrive at the claimed subject-matter in order to improve the barrier properties by forming a laminar structure.

This is not persuasive because there is no evidence that such a manner of extruding spacer profiles in order to achieve a laminar flow was generally known and used prior to the attacked patent. It cannot thus be regarded as being part of the common general knowledge.

5.2 D1 or D2 in combination with D7, D9, D11 - D18, D20, D21 or D23

The appellant also referred to documents D7, D9, D11 - D18, D20, D21 or D23 as support for their view that this formed part of the common general knowledge.

These documents disclose:

D7: discloses using silicate layers in a nylon 6-clay hybrid (p. 458, 3**(rd) paragraph). These improve the gas "barrierability" (impermeability) of the film.

D9: relates to the use of sheet silicates in barrier films and discloses in paragraph [0022] that a labyrinth structure formed by stratified silicate can provide a gas barrier layer.

D11: discloses a food container such as a cup, tub or tray with a coat forming a barrier layer, see paragraph [0001].

D12: relates to improving the permeation resistance of thin-walled articles such as film or containers (col. 3, l. 23 - 30). The platelets are disposed parallel to the broad face of the film. It is not disclosed how many lamella layers there are and consequently features 1.4a) and b), which require a plurality of layers, are not known from this document.

D13: discloses a film, see p. 1, l. 13 - 18, but not the structure of the sheet silicate.

D14: discloses a coating composition, see col. 4, l. 7 - 11. Sheet silicates are disclosed, see col. 5, l. 18 - 25, but not their structure.

D15: discloses a method for producing a multi-layered silicate but there is no teaching that would lead the skilled person to combine it with D1 or D2 in a window spacer.

D16: discloses a moisture proof paper sheet and stacks of sheets (p. 2, 1**(st) para.).

D17: discloses a vapour barrier including a crystalline platelet barrier, p. 2, 1**(st) para.

D18: relates to a moisture vapour barrier for paper and paperboard, see claim 1.

D20: mica-flake paper for electroluminescent lights, see claim 1.

D21: discloses a diffusion barrier for a plastic composite isolator, see claim 1.

D23: discloses a photovoltaic device with a barrier layer.

It is correct, as argued by the appellant, that the above documents demonstrate that the use of silicates to provide a barrier was well known before the priority date of the attacked patent. However, the documents cited are not related to spacer profiles but are related to films, foils or paper. The appellant has not shown that the relevant skilled person, i.e. the skilled person tasked with solving the objective technical problem related to the spacer, would combine D1 or D2 with the teaching of documents related to different fields. Thus, it would not have been obvious for the skilled person to apply the teaching of these documents to the spacer profiles known from D1 or D2.

The subject-matter of claim 1 involves an inventive step with regard to either D1 or D2 as closest prior art.

5.3 D3 or D25 as closest prior art

D3 discloses a spacer profile according to the preamble of claim 1 (see Fig. 2). This spacer has a diffusion barrier made of metal (see paragraph [0026]) and gaps to reduce heat conductivity. These gaps reduce the effectiveness of the diffusion barrier.

D25 also discloses a spacer profile according to the preamble of claim 1, see claim 1 of D25. This profile has a one-piece diffusion barrier film 30. The film 30 is preferably metallic (see paragraph [0073]).

The problem to be solved is therefore to provide a spacer which has a best possible barrier resistance without increasing the thermal conductivity.

The appellant argued that the skilled person would know that metal was a good conductor of heat and would therefore replace the metal barrier with a material with lower thermal conductivity. The appellant further argued that the skilled person would have considered D1, D2 or D7, D9, D11 - D18, D20, D21, D23 and would have thereby arrived at the subject-matter of claim 1.

This is not however convincing because, as discussed above, D1 and D2 do not disclose the features 1.4a) and 1.4b) of claim 1.

Moreover, as discussed above with respect to D1 and D2 as closest prior art, the skilled person would not have applied features from unrelated technical fields such as those addressed in D7, D9, D11 - D18, D20, D21 or D23 to a spacer profile for a door or window or facade elements. In this respect, the appellant has not identified specific teachings in these documents that would indicate their suitability for the use in a spacer profile for a door or window or facade elements.

The subject-matter of claim 1 thus involves an inventive step with respect to either D3 or D25 as closest prior art.