T 0668/07 19-03-2009

1. The appeal is admissible.

2. Rule 57a EPC 1973

Rule 57a EPC 1973 (Rule 80 EPC 2000) allows amendment of a European patent provided that the amendment is occasioned by a ground of opposition specified in Article 100 EPC, even if the respective ground has not been invoked by the opponent.

Claim 1 of the granted patent defines a " Stab-resistant material made from at least two woven fabrics joined together via a polymer film…". During the opposition procedure, this claim was amended to specify that the "stab-resistant material is made from at least one laminate consisting of two woven fabrics laminated together with a polymer film such that the two woven fabrics are joined via the polymer film…". The Appellant considers that the amendment is not occasioned by one of the grounds of opposition given in Article 100 EPC and hence is contrary to Rule 57a EPC 1973.

The amendment was put forward by the Respondents/Patent proprietors in their reply to the notice of opposition, arguing that, although D3 discloses a material made up of layers, each one consisting of a woven fabric and a polymer film, the amended claim 1 is distinguished from D3 in that it is limited to layer(s) of laminate(s) consisting of two woven fabrics joined by a polymer film.

The amendment was therefore made in response to the allegation that the subject-matter of the granted claim lacked novelty over D3. Since lack of novelty is a ground for opposition under Article 100(a), there is no objection under Rule 57a EPC 1973 to the amendment.

3. Article 123 EPC

The Appellant argues that the application as originally filed and the granted patent specification disclose a stab-resistant material that functions as such when just two fabrics are joined by a single polymer film. The amendment to claim 1 now means that this requirement is no longer necessary, as something made from the laminate is defined as being stab-resistant rather than the laminate itself. The amendment is thus said to fall foul of Article 123(2) EPC as there is no basis in the original application for a laminate that is not stab-resistant. In addition, the amended claim covers stab-resistant material made from a number of non-stab resistant laminates, and hence the scope of the claim has been broadened contrary to Article 123(3) EPC.

Claim 1 of the original PCT application (WO-A-00/08411) defines a stab-resistant material made from at least two woven fabrics joined together via a polymer film. Dependent claim 2 and the paragraph bridging pages 4 and 5 of the PCT application disclose lamination of the two fabrics with a polymer film and the making of a material from various numbers of laminates. The features of the amendment can thus be derived from the application as originally filed, in accordance with Article 123(2) EPC.

The present claim 1 requires the material to be made from at least one laminate, ie it includes a single laminate, and a single laminate consists of two fabrics joined via the polymer film, as is defined in granted claim 1. On this basis there is no increase in the scope of the claim contrary to Article 123(3) EPC.

There is no basis for the distinction that two fabrics joined by a polymer film is stab-resistant, whereas a laminate made of the same layers is not, as was suggested by the Appellant.

The amendment therefore meets the requirements of Article 123 EPC.

4. Novelty (Article 54 EPC)

4.1 The Appellant submits that the claimed subject-matter lacks novelty over D3. Document D3 is directed to ballistic resistant fabric articles, which are also said to have penetration resistance against a threat such as a knife or an ice pick (column 3, lines 16 to 18). Although the Respondents argue that stab resistance implies a resistance to cutting in addition to penetration, it is clear from the above citation that D3 concerns material that is intended to be stab-resistant, even if it is not expressly mentioned as such.

4.2 Claim 1 requires that the stab-resistant material is made from at least one laminate consisting of two woven fabrics laminated together with a polymer film such that the fabrics are joined via the polymer film.

The embodiment shown in Figure 2 of D3 has alternate layers of fibrous and polymer material, which according to the Appellant meets the requirement of claim 1. The relevant passage in the description (column 3, lines 45 to 46) reads "Layers 12a includes two layers fibrous layers 14a and polymeric layer 16a, …". This sentence is not written clearly, but when read in combination with Figure 2, which shows only one layer as 14a, only one layer as 16a and only one pair as 12a, it is apparent that the sentence should be understood as meaning "layer 12a includes two layers, fibrous layer 14a and polymeric layer 16a".

The paragraph goes on (column 3, lines 52 to 53) to say that "layer 12 includes at least one layer 14 and one layer 16", which the Appellant submits is disclosure of the claimed laminate. However, the wording of D3 is once again not clear, in that it is not certain if "at least" refers just to layer 14 or to both layers 14 and 16. Given the disclosure of Figure 2 in combination with column 3, lines 45 to 46, as discussed above, the latter interpretation is the better of the two.

An important argument presented by the Appellant is that when the layers of D3 are bonded or laminated together, it is inevitable that two fabric layers will be laminated together with a polymer layer. In support of this submission, the Appellant refers to column 4, lines 44 to 49: "Fibrous layer 14 may be laminated or bonded to polymeric layer 16 by the polymer in polymeric layer 16 or through the use of an adhesive or the like. In addition to bonding, polymeric layer 16 and fibrous layer 14 may be secured together using conventional securing means as described above." The "conventional securing means" are cited at column 3, lines 58 to 64 as being "bolts, rivets, adhesive, staples, stitches and the like". There is no doubt that the cited passage discloses a fibrous layer laminated to a polymer layer, but there is no clear indication that further lamination takes place such that a polymer layer would be laminated to two fibrous layers. Additional securing means may be used, but this is mentioned in the context of bonding one fibrous layer to one polymer layer. The overall material is then obtained by securing together layers, each consisting of a fibrous layer and a polymer layer, by "bolts, rivets, adhesive, staples, stitches and the like" (column 3, lines 58 to 64).

An illustration of how the material of D3 is made is given in Example 2 (columns 23 and 24), which explains that each fabric layer is laminated to a Caprolan® Nylon 6 film. Five fabric layers at a time, separated by release layers, are then laminated; the use of release layers makes it clear that no further bonding between fabric and polymer layers takes place.

Throughout D3 it is apparent that one fibrous layer must be bonded to one polymer layer, but it cannot be said that two fibrous layers laminated via a polymer film is unambiguously disclosed.

4.3 According to claim 1, the fabrics comprise yarns with a tensile strength of at least 900 MPa. D3 discloses (column 6, lines 26 to 52) fibres having a tensile strength of at least 5 g/denier, preferably higher. Since 7 g/denier is equated to 900 MPa (see D1, page 2, lines 9 to 11) it is clear that D3 concerns fibres having the strength defined in claim 1, and indeed, this was not disputed by the parties.

Claim 1 requires that the polymer film has a tensile strength of at least 10 MPa and a flexural modulus of 1500 to 4500 MPa. A modulus is discussed at column 13, lines 37 to 40, but given the ambiguous nature of the exact meaning of the modulus being discussed, as highlighted by the parties (see VI(c) above), nothing meaningful can be derived from this passage. However, example 2 of D3 employs a polymer layer of Caprolan® Nylon 6. According to the data sheets of D5, the yield tensile strength of nylon 6 is 85 MPa and the flexural modulus is 2825 MPa. The tensile strength and flexural modulus according to both the contested patent and D5 are determined by ASTM tests D-638 and D-790 respectively. It can thus be concluded that the polymer film used in example 2 of D3 has the mechanical properties required by claim 1.

4.4 In summary, the stab resistant material of claim 1 differs from that disclosed in D3 only in terms of the structure of the laminate, which consists of two fabric layers joined via the polymer layer.

5. Inventive Step (Article 56 EPC)

5.1 Document D3 describes a material that is stab-resistant (see paragraph 4.1 above), and hence provides an appropriate starting point for the assessment of inventive step.

5.2 Starting from D3, the problem facing the skilled person is to improve the effectiveness of the stab-resistant material and the wearing comfort of clothes made from such material (see paragraph [0003] of the contested patent).

5.3 The proposed solution is to arrange the layers so that two woven fabric layers are laminated together via a polymer layer.

5.4 It is well known (see D1, page 1, lines 18 to 23 and page 2, lines 18 to 29) that the polymer in the material contributes little to ballistic or stab resistance, but has the function of holding the strong fibres in place in order to prevent them from being pushed aside by a sharp or pointed object. This is the approach adopted in both D3 and D1, in which the fibres are bonded with a polymer layer.

Knowing that the stab resistance derives primarily from the fibre materials, the tendency of the skilled person reading D3 alone, and faced with the problem of increasing stab-resistance, would be to increase the number of layers of fibre/polymer laminates. However, this would lead to a less comfortable garment; the skilled person must either select from the large number of materials presented in D3 those that are both light and strong or strike a balance between protection and comfort. There is no hint in D3 to laminate fibre layers either side of the polymer layer.

D1 has basically the same approach as D3, in that a high-tenacity fibrous layer is bonded with a polymer layer, but according to D1 the polymer must have specific mechanical properties (see D1, page 2, lines 3 to 6). In addition, D1 states (page 5, lines 23 to 29) that "the polymeric continuum can be suitably applied as a layer in the composition by being bonded at one side or at both sides to a fiber-containing layer, depending on application, and, in more practical terms, on the availability of the appropriate manufacturing process. In a preferred embodiment of the invention, the fiber-containing layer is embedded in the polymeric continuum in order to immobilize the fibers, resulting in an extremely strong composition". According to the Appellant, this provides the skilled person with a clear teaching to bond fibre layers to both sides of the polymer.

It is true that this is an option for the skilled person, but the more important question to be answered is whether there is any teaching that this would provide a solution to the problem of increasing both stab-resistance and comfort.

D1 provides no explanation as to why two fabric layers should be joined via a polymer layer, merely saying that it depends on "application and availability of appropriate manufacturing process". There is certainly no indication that this would lead to an increase in both stab-resistance and comfort; on the contrary, according to the preferred embodiment of D1, an extremely strong composition is obtained when the fibres are embedded in the polymer, which is completely different from having fibres either side of the polymer.

5.5 Seeing as there is no clear teaching in D1 that lamination of two fibre layers via a polymer film will provide improved stab-resistance and result in more comfortable clothing, the solution can only be recognised in D1 once the skilled person is made aware of the subject-matter of claim 1. Thus, the claimed material has an inventive step in light of D3 alone or in combination with D1.

5.6 Starting from D1

Although the parties considered D3 to provide the most promising starting point for the assessment of inventive step, the Opposition Division viewed D1 as being the closest prior art, since it corresponds to the preamble of claim 1. The material of claim 1 differs from that of D1 in that the polymer film has a greater flexural modulus, defined as 1500 to 4500 MPa, compared with 42 to 1000 MPa as disclosed in D1.

Starting from D1, the objective problem is, as set out in the introduction to the contested patent, the improvement in stab-resistance and wearing comfort. The proposed solution is to employ a polymeric layer made from a polymer having a higher flexural modulus than that of D1. This means that fewer layers are required to make a lighter garment that provides comparable stab protection; any loss in flexibility is offset by having fewer layers.

D1 discloses (page 5, lines 3 to 12) that a polymer with a flexural modulus greater than 1000 MPa is too stiff to effectively withstand puncture or be worn comfortably. The skilled person only aware of D1 therefore has no reason to go against this teaching. Since D1 teaches away from the proposed solution, the conclusion of the Opposition Division that the claimed subject-matter has an inventive step when starting from D1 is sound.

5.7 Scope of Claim 1

The Appellant submits that the definition given in claim 1 is so broad that it includes materials that do not have the required properties, such that the inventive step is not present across the entire scope of the claim. Polystyrene, a brittle polymer, is cited as an example that meets the requirements of claim 1, but would fail to provide any stab-resistance; polycarbonate also falls within the claim, but is so rigid that any garment made from it would be most uncomfortable to wear.

However, the Appellant has not provided any convincing evidence of laminates that do not show some stab-resistance and that cannot be worn as a garment. Stab-resistance is primarily derived from the fibre layers, so even if polystyrene were to be used as the polymer film, the resulting material would exhibit some resistance to stabbing. Likewise, there is no evidence that a stab-resistant garment cannot be made from a laminate incorporating a thin film of polycarbonate as the polymer. For these reasons the Board does not agree with the Appellant's submission.

6. Lack of Sufficiency of Disclosure (Article 100(b) EPC)

6.1 Lack of sufficiency of disclosure was cited as a ground of opposition in the notice of opposition on the basis of the alleged inability to determine the flexural modulus of the polymer film (see paragraphs 1 to 6 of the notice of opposition). It appears from the letter of the Appellant/Opponent dated 3 October 2006 (paragraph 4) that during the opposition proceedings this objection under Article 100(b) EPC was not maintained. The ground was nevertheless considered by the Opposition Division in its decision (see paragraph 2 on page 4 of the decision), and because it forms part of the contested decision, the ground per se is also a part of the appeal proceedings.

6.2 However, in the grounds of appeal the Appellant raised the objection under Article 100(b) EPC using a completely different set of arguments than those put forward in opposition proceedings. It is therefore first of all necessary to decide whether or not to admit the Appellant's submissions into the appeal proceedings. In exercising its discretion, the Board has to consider why this argument was not put forward in the proceedings before the Opposition Division (as it ought to have been), and whether such material is prima facie likely to prejudice the maintenance of the patent (see T 1002/92, point 3.4).

6.3 The reason put forward by the Appellant for the tardiness of the argument is that it had only been thought of at a late stage, and given its relevance and the interest of the public not to have invalid patents in force, it should be admitted into the proceedings.

6.4 The Appellant's submission itself involves two arguments. Firstly, the claim covers a situation where the polymer film and the yarns may be of the same material and one is not distinguishable from the other, hence it is not possible for skilled persons to know whether or not they are working within the scope of the claim. Secondly, the patent does not teach how to make products of the required stab resistance from the broad range of component materials disclosed in the patent specification, and hence over the whole area claimed.

The second argument relates more to inventive step in that the technical effect should be present across all subject-matter claimed (Articles 100(a) and 56 EPC), and this has been dealt with in paragraph 5.7 above. The first argument relates more to the issue of clarity of the scope of protection (Article 84 EPC). Article 100(b) EPC simply requires that the invention be described so that it can be carried out in practice, and in this case the patent specification (paragraphs [0020] and [0021]) provides specific examples that demonstrate how to obtain materials in accordance with the invention. Since neither of the arguments appear at first sight to prejudice the maintenance of the patent, the Board sees no reason to admit the Appellant's late-filed submissions into the proceedings.

7. Summary

None of the cited objections prejudices the maintenance of the patent on the basis of the claims of the main request.