T 0817/11 13-02-2014

1. The appeal is admissible.

Main request (patent as granted)

2. Sufficiency of disclosure

2.1 In order to meet the requirements of Art. 83 EPC, an invention has to be disclosed in a manner sufficiently clear and complete for it to be carried out by the skilled person in the whole area claimed without undue burden, on the basis of the information provided in the patent specification and, if necessary, using common general knowledge. This means in the present case that the skilled person should be capable, inter alia, to prepare without undue burden cured coatings according to granted claim 1.

2.2 Granted claim 1 is directed to cured coatings having a higher concentration of particles at the air/coating interface than in the bulk of the coating, those domains being specified in the claims as the "surface region" and "bulk region", respectively; they are also defined in paragraphs [0021] and [0023]-[0025] of the patent in suit. That characteristic is referred to hereinafter as "surface enrichment".

2.2.1 According to paragraphs [0023]-[0025] of the patent in suit, the surface enrichment may be defined in different ways and determined either by surface analysis techniques or by visual inspection using microscopy techniques. In the patent in suit and throughout the proceedings, the appellant consistently referred to visual inspection, in particular in order to conclude that the coatings illustrated in Figures 1, 4 and 7-10 of the patent in suit showed surface enrichment whereas that of Figure 2 did not. According to that interpretation, surface enrichment is considered to be present if the cured coating presents a uniform increase in particle concentration at the air/interface of the coating ("surface region" according to claim 1) as compared to within the coating ("bulk region" according to claim 1). That reading of the feature "surface enrichment" is in line with the interpretation of Figures 1 to 4 provided in paragraphs [0265] to [0268] of the patent in suit and is similar to the phenomenon of "flooding" defined in D8 (page 10, section V) and D9 (paragraph bridging pages 197 and 198) in relation to pigment mixtures in coatings.

2.2.2 The respondents' argument according to which, due to the wording "a" concentration, "a" surface region, and "a" bulk region, granted claim 1 encompassed coatings in which surface enrichment was only present at a single location does not make sense technically and is also not in line with the patent specification as a whole. Therefore, that reading of claim 1 cannot be followed.

2.3 Granted claim 1 is defined both in terms of its components a) to c) (film forming material having reactive functional group(s), particles and surface active agent) as well as by the use of a feature related to surface enrichment, which constitutes a limitation of the claimed subject-matter in terms of the result to be achieved. However, as the definition of components a) to c) is very broad, the subject-matter defined in granted claim 1 encompasses a huge variety of possible combinations. That all those possible combinations of components a) to c) according to granted claim 1, in any amount, necessarily lead to surface enrichment is neither credible, nor was it ever argued during the proceedings and during the oral proceedings before the Board the appellant even agreed that such was not the case. Therefore, it has to be assessed whether the patent in suit discloses a technical concept fit for generalisation that makes available to the skilled person the specific combinations out of the many possibilities encompassed by the subject-matter of claim 1 that do lead to surface enrichment. In other words, whether the skilled person finds sufficient guidance for an appropriate selection of components a) to c) in order to prepare, with a good chance of success, a cured coating exhibiting surface enrichment (see Case Law of the Boards of Appeal of the EPO, 7th edition, 2013, section II.C.4.2 and 4.4).

2.4 According to the patent specification, the coatings according to granted claim 1 may be prepared by curing compositions comprising different components defined as follows:

(a) film forming material(s) having at least one reactive functional group (feature a) of granted claims 1 and 27-29; paragraphs [0136]-[0158]);

(b) particles (feature b) of granted claims 1 and 14-26; paragraphs [0032]-[0074]);

(c) surface active agent(s) (feature c) of granted claims 1 and 3-13; paragraphs [0075]-[0134]);

(d) optionally reactant(s) (granted claims 2 and 30-42; paragraphs [0135] and [0159]-[0203]). In that respect, it is specified in paragraph [0135] that a "reactant" is a material comprising a functional group that is reactive with at least one functional group selected from at least one functional group of the at least one polysiloxane and at least one functional group of the (film forming) material;

(e) optionally catalyst(s) (granted claims 43-48; paragraphs [0206]-[0207]);

(f) optionally further components (paragraph [0208]).

Many embodiments of each of those components are exemplified in the passages of the patent specification cited above. However, all the information provided in those passages is given in very general terms, most features being with the indication that they are "non limiting" examples and/or "embodiments". In particular, the patent specification does not contain any information that could serve as a guidance for the skilled person in order to identify e.g. which combinations of components and/or which amounts thereof should be used or which process steps should be applied in order to obtain cured coatings having surface enrichment according to granted claim 1. In the present case, it was not shown that the skilled person could rely on his general knowledge in order to compensate for that lack of information. On the contrary, not only would the skilled person be aware that not all possible combinations of components automatically provide the surface enrichment specified in the claims, but it is also known in the art that surface enrichment is very sensitive and highly depends on the nature of the components, e.g. solvent, particle nature and size, additives and/or the preparation process (D9: page 198: lines 4-9 and bottom paragraph; top of page 200; last paragraph on page 201). Although D9 is primarily directed to pigment mixtures in coatings, the conclusions drawn therein are considered to be relevant for the cured coating defined in granted claim 1 in view of the similarity of the components present in both systems and of the broadness of the definition of components a) to c).

2.5 The only further information given in the patent in suit to prepare the claimed cured coatings resides in the examples.

In the present case, many examples of the application as filed had been deleted during the examination proceedings and are not present anymore in the patent in suit. As a result, a number of inconsistencies are present in the examples of the patent in suit, such as reference being made to components that are not specified elsewhere in the patent in suit. This is in particular relevant in respect of examples 1A, 1B and 2A, which will be considered below (examples 1A and 1C refer to the catalyst of non-existing example 12 and example 1B to the acrylic polyol of non-existing Example 23A; example 2A refers to non-existing Example 23C). Those inconsistencies render the examples unintelligible without making reference to the original application. Therefore, the examples of the patent in suit are read hereinafter, when necessary, in the light of the information provided in the application as filed.

2.5.1 Example 1A of the patent in suit is directed to a cured coating prepared from a composition comprising an acrylic polyol, colloidal silica and a polysiloxane polyol as components a), b) and c), respectively. according to granted claim 1, whereby the silica and the polysiloxane were added as separate components (page 31, lines 1-2 of the patent in suit). As indicated in paragraph [0265] of the patent in suit, Figure 1 shows that the cured coating prepared in example 1A exhibits surface enrichment.

2.5.2 Example 1C of the patent in suit is directed to a cured coating prepared from a composition comprising an acrylic polyol, colloidal silica and a polysiloxane polyol as components a), b) and c), respectively. according to granted claim 1, whereby the silica and the polysiloxane were added as a predispersion (page 31, lines 3-6 of the patent in suit).

Although Figure 4 of the patent in suit is indicated to be a TEM picture of a cured coating prepared using a predispersion of silica and polysiloxane (paragraph [0268]), it contains no indication that Figure 4 actually illustrates the coating prepared in Example 1C, which was not contested by the appellant. Since example 1C is indicated in the patent in suit as illustrative of the invention and in the absence of any evidence to the contrary, it is nevertheless credible that the cured coating prepared in Example 1C exhibits surface enrichment.

2.5.3 Further cured coatings were prepared in examples 2A, 3B-G (Figures 7-10), and 4-6 of the patent in suit, all using an acrylic polyol film-forming material, colloidal silica particles and polysiloxane polyol surface active agents (only in example 5 a polysiloxane polyol that differed from the other ones one was used). Those examples are indicated as being according to the invention (paragraphs [0247]-[0254]). Moreover, silicone oils are known in the art to be very effective in improving surface enrichment (D8: page 10, section V). Therefore, and in the absence of any evidence to the contrary, it can be accepted that the cured coatings prepared in those examples exhibit surface enrichment.

2.5.4 However, all the examples of the patent in suit illustrating the subject-matter of granted claim 1 were performed using only a single kind of film forming material (acrylic polyol), a single kind of particles (colloidal silica) and a single kind of surface active agent (polysiloxane polyol), the positive effect of which on surface enrichment is known.

2.5.5 There is no evidence on file that the other surface active agents encompassed by the claims and cited in the patent in suit as suitable compounds have the same effect. In that respect, Example 1B of the patent in suit describes a cured coating prepared from a composition comprising an acrylic polyol, colloidal silica and polybutylacrylate. Example 1B is indicated as a comparative example. It was made without polysiloxane surface active agent (paragraph [0257]) but the curable composition prepared therein does contain polybutylacrylate, which is a surface active agent in the sense of the patent in suit as explicitly stated in paragraph [0085]. The curable composition prepared in Example 1B is therefore a curable composition within the terms of granted claim 1. Whether or not polybutylacrylate was used as a surface active agent or as a flow additive, as argued by the appellant, is, in the absence of any indication in that respect in the patent in suit, irrelevant. Considering that the cured coatings prepared in example 1B do not exhibit surface enrichment, as shown in Figure 2 and explained in paragraph [0266] of the patent in suit, the patent itself shows that merely following the teaching of the patent specification is not sufficient to prepare a cured coating exhibiting surface enrichment according to granted claim 1. This leads to the conclusion that not all combinations of the components a) to c) listed in the patent in suit necessarily lead to surface enrichment. Also, it cannot be derived from the patent specification what should be changed in example 1B in order to obtain surface enrichment. Hence, although the examples of the patent in suit show that some cured coatings according to granted claim 1 may be prepared, they do not provide sufficient information on how to proceed in order to prepare, in a reliable way, cured coatings having surface enrichment according to granted claim 1 that comprise different combinations of components than those actually used in the specific examples of the patent in suit, but fall within the definition of components a), b) and c) of claim 1. In that light, the appellant's argument that the patent as whole provided sufficient teaching in order to carry out the invention cannot be followed.

2.5.6 That conclusion is not changed by D15 and D16 which show that it is possible to prepare some coatings according to claim 1. In the present case, in view of the broad scope of the claimed subject-matter, it is not enough that the patent in suit provides at least one way of carrying out the invention or that some combinations will achieve the required surface enrichment. The issue is that it should provide a clear guidance how to prepare successfully and without undue burden cured coatings exhibiting surface enrichment according to claim 1, also using components different from the few used in the examples.

2.6 The appellant argued that Example 1C, compared to Example 1A, showed that better surface enrichment was obtained by using a predispersion of the particles in the surface active agent. However, the components and the amounts thereof used in Examples 1A and 1C differ in several ways (see the Tables of paragraphs [0259] and [0261]: amounts of methyl amyl ketone and silica; nature and amount of acrylic polyol; amount of polysiloxane polyol; amount of catalyst; different Desmodur reactants). Therefore those examples do not provide a proper comparison and it cannot be concluded on that basis that the use of a predispersion of colloidal silica in polysiloxane leads to an improvement in surface enrichment. Besides, since Example 1C was also performed using components as identified in section 2.5.4 above, it does not change the above conclusion regarding the lack of guidance.

2.7 Under these circumstances, the skilled person wanting to prepare a coating according to granted claim 1 is left with the task of performing an elaborate program in order to find out which combination of a) film forming materials, b) particles, c) surface active agent and which preparation conditions should be used. In other words, the skilled person can only establish by trial and error whether or not his particular choice out of the numerous possibilities will provide the surface enrichment required by claim 1, which is contrary to the requirements of Art. 83 EPC.

2.8 The above conclusion is in line with e.g. T 1121/03 and T 369/05 since the patent in suit does not provide a technical concept fit for generalisation over the whole scope of the claims for preparing, without undue burden, cured coatings exhibiting surface enrichment.

2.9 In view of the above, it is not necessary to consider D14, relied upon by the respondents, or Examples 22F and 22H of the original application, relied upon by the opposition division.

2.10 For these reasons, the main request does not meet the requirements of sufficiency of disclosure (Art. 83 EPC) and has to be refused.

2.11 Under these circumstances, the question whether the skilled person is in a position unambiguously to determine whether he is working inside or outside the claims would be related to a lack of sufficiency (Art. 83 EPC) or would rather be a clarity issue (Art. 84 EPC), needs not be addressed.

Auxiliary requests

3. The admission to the proceedings of each of auxiliary requests 1 to 8, which were all filed in reply to the communication of the Board accompanying the summons to oral proceedings, is subject to the Board's discretion (Art. 13(1) and (3) RPBA).

Auxiliary requests 1 and 2

4. Since claim 1 of each of auxiliary requests 1 and 2 is identical to claim 1 of the main request, the same reasoning regarding sufficiency of disclosure applies, thus rendering auxiliary requests 1 and 2 not clearly allowable. Therefore, auxiliary requests 1 and 2 are not admitted to the proceedings.

Auxiliary requests 3 and 4

5. Auxiliary requests 3 and 4 both contain an identical claim 1, which corresponds to granted claim 1 amended by specifying that the surface active agent c) is selected "from at least one polysiloxane and at least one fluoropolymer".

5.1 The amendment made to claim 1 aims in particular at excluding the subject-matter of example 1B of the patent in suit, wherein a coating that does not show surface enrichment is prepared (see section 2.5.5 above). The relevance of example 1B in respect of the issue of lack of sufficiency had been on file from the beginning of the opposition proceedings (page 6 of opponent's 02 notice of opposition) and was also addressed in the contested decision (paragraph bridging pages 6 and 7). Nevertheless, a claim directed to the subject-matter now being defined was neither submitted during the opposition proceedings nor with the statement of grounds of the appeal. In fact, the nature of the surface active agent had never been in the focus until the filing of the (then) first auxiliary request with letter of 20 June 2012. Such a late filing contravenes the requirements of Art. 12(2) RPBA according to which the statement of grounds of appeal shall contain a party's complete case.

5.2 Apart from their late filing, auxiliary requests 3 and 4 further raise prima facie concerns, e.g. in relation to:

(a) Art. 83 EPC: the amendment made does not appear to remove the objection of lack of sufficiency raised against the main request since claim 1 is still directed to a multitude of film forming materials and particles. Regarding the surface active agents, the patent in suit does not provide any information regarding the fluoropolymers to be used and the examples only illustrate one kind of polysiloxane, namely polysiloxane polyol, which comprises reactive functional groups;

(b) Art. 123(2) EPC: claim 43 of the application as filed was directed to feature a) of claim 1 but only in combination with a "reactant" (through its dependency on original claims 42 and 35), which is not reflected in claim 1. In addition, if a basis for each feature a) to c) specified in claim 1 may be found in the application as filed, it is always in passages directed to specific embodiments (page 9, paragraph 1: particles; page 31, line 2 to page 47, first full paragraph: polysiloxanes; page 47, last paragraph: film forming material optionally having a reactive functional group). In that respect, it is further indicated on page 28, lines 2-3, that the surface active agent can be amphiphilic. Since that feature is not reflected in claim 1, it raises further concerns whether or not a further selection within the ambit of the application as filed is required in order to arrive at the subject-matter now being claimed. Under these circumstances it is questionable whether the specific combination of technical features according to claim 1 is directly and unambiguously disclosed in the application as filed (Art. 123(2) EPC).

5.3 Considering their late filing and the fact that they are not clearly allowable, auxiliary requests 3 and 4 are not admitted to the proceedings.

Auxiliary requests 5 and 6

6. Auxiliary requests 5 and 6 contain identical claims 1 which correspond to granted claim 1 amended by replacing features b) and c) by the new feature "b) a dispersion of colloidal particles in a polysiloxane surface active agent containing reactive functional groups."

6.1 For the same reasons as indicated above in respect of auxiliary requests 3 and 4 (section 5.1), there is no reason justifying the filing of auxiliary requests 5 and 6 at such a late stage of the proceedings.

In addition, the first time during the whole of the proceedings that a coating prepared using a specific predispersion appears in the claims is with claim 1 of auxiliary request 2 filed with letter of 20 June 2012 (i.e. after the statement of grounds of appeal was filed). Therefore, the same considerations apply as for auxiliary requests 3 and 4 (section 5.1 above).

6.2 Auxiliary requests 5 and 6 further raise prima facie concerns, e.g. in relation to:

(a) Art. 123(2) EPC: even if the argument of the appellant according to which new feature b) was based on page 26, first paragraph of the application as filed, was to be followed, it appears questionable whether the specific combination of features defining the subject-matter now being claimed, at this degree of generality, would be directly and unambiguously derivable from the application as filed, in particular from the combination of said passage on page 46 and that at the bottom of page 47. In that respect, the first paragraph on page 26 in particular is explicitly not limited to the use of polysiloxanes containing reactive functional groups;

(b) Art. 84 EPC: feature b) of claim 1 was not present in the granted claims so that it would have to be assessed whether it fulfils the requirements of Art. 84 EPC. Said feature b) requires that the curable coating composition comprises simultaneously a film forming material and a dispersion of colloidal particles "in a polysiloxane". However, it does not appear possible to identify in the curable composition comprising all its components whether or not the colloidal particles are present as a dispersion in the polysiloxane. The argument of the appellant that feature b) was directed to the starting material is not reflected in the wording of the claim.

6.3 Under these circumstances auxiliary requests 5 and 6 are both late filed and not clearly allowable and, consequently, not admitted to the proceedings.

Auxiliary requests 7 and 8

7. Auxiliary requests 7 and 8 contain identical claims 1, which correspond to claim 1 of auxiliary request 5 further amended by limiting the nature of the particles in feature b).

7.1 Each of auxiliary requests 7 and 8 presents the same deficiencies as auxiliary requests 5 and 6 in respect of their late filing and the fact that they are not clearly allowable in respect of Art. 123(2) EPC and Art. 84 EPC.

7.2 Therefore, auxiliary requests 7 and 8 are not admitted to the proceedings.

8. Since the main request of the appellant (patent proprietor) is not allowable and none of auxiliary requests 1 to 8 is admissible, the appeal has to be dismissed.