T 1642/13 09-09-2016

Main request

1. Admissibility

1.1 The operative main request was filed as auxiliary request 2 with letter of 9 August 2016, i.e. one month before the oral proceedings before the Board and after the communication of the Board setting out its preliminary view of the case had been received. Therefore it represents an amendment to a party's case and its admission to the proceedings undergoes the stipulations of Articles 13(1) and 13(3) RPBA.

1.2 As can be seen from the file history, the patent proprietor's first main request in appeal was to maintain the patent as granted. Then the main request was amended with the response to the rejoinders of opponents 1 and 2 by inserting the subject-matter of granted claim 20 into claim 1. This has been indicated to be in reply to the criticism by opponent 1 that the parameter "moisture content" was not sufficiently disclosed. Following the Board's preliminary written opinion the patent proprietor reverted to the main request submitted with the statement of grounds of appeal. It is credible that it was made in view of the Board's own remark that the insertion of the expression "surface moisture level" contained in granted claim 20 alongside the expression "total surface moisture level" already present in claim 1 could give rise to new issues that needed to be discussed for the first time on appeal. This constitutes, in the Board's view, a proper justification for deleting the amendment made and therefore reverting in a first step to the main request submitted with the statement of grounds of appeal, i.e. the patent as granted.

1.3 The operative main request is based on granted claims 1 and 4-20 (the other two granted dependent claims 2 and 3 were deleted). Considering that the patent proprietor's main request submitted together with the statement of grounds of appeal was the maintenance of the patent as granted, which was also the main request defended before the opposition division, the opponents have had ample time during the proceedings to deal with the other claims of the operative main request, as can be seen e.g. from the arguments put forward in the opponents' rejoinders to the statement of grounds of appeal in the light of their earlier submissions. Consequently, the admission to the proceedings of the operative main request may not raise issues which the other parties or the Board cannot reasonably be expected to deal without adjournment of the oral proceedings. Since the main request was further filed one month before the oral proceedings before the Board, the opponents had ample time to prepare their case. Therefore, there was no reason for the Board not to

admit the main request pursuant to

Article 13(3) RPBA.

1.4 It is correct that, as argued by the opponents, the patent proprietor could have filed the operative main request earlier in the proceedings e.g. together with the statement of grounds of appeal (in particular considering the objection of lack of sufficient disclosure retained by the opposition division against the then pending auxiliary request 5), in reply to the opponents' rejoinders to the statement of grounds of appeal (in which objections of lack of sufficiently were raised against granted claims 2-3), or in reply to the Board's first communication dated 4 December 2015 (asking the parties to file any submissions as soon as possible to allow the Board to take them into account). However, there is no evidence of a deliberate abuse of procedure by the patent proprietor. The deletion of dependent claims 2 and 3 as granted is an appropriate answer to the objection of insufficient disclosure raised by the opponents, which can neither be held to be against procedural economy nor to raise complex issues. In addition, considering the amendment to claim 1, the patent proprietor had argued in writing that the Karl Fischer method mentioned in granted claim 20 was a method used to measure the total surface moisture content, from which can be inferred that the patent proprietor considered the expressions "surface moisture level" determined by Karl Fischer as indicated in granted claim 20 and "total surface moisture level" mentioned in granted claim 1 as to correspond to the same technical feature. Therefore, it could not be concluded that the insertion (or the deletion) of granted claim 20 into granted claim 1 changed the scope of debates i.e. ran counter procedural economy.

1.5 Decision T 122/10, which was relied upon by opponent 1, dealt with the admission to the proceedings of requests filed for the first time during the oral proceedings before the Board (see e.g sections 3.4 and 3.9 of the reasons), which is a different factual situation as the present one in which the operative main request was submitted one month before the oral proceedings. Also, the Board held in decision T 122/10 that "the framework of the appeal would have been altered completely if the new requests were admitted" (section 3.6 of the reasons), which is not the case here, as explained in section 1.4 above. Finally, as can be derived from the preceding sections, the present decision does not deviate from T 122/10 (section 3.7 of the reasons) since the admission of a late filed request is subject to the Board's discretion pursuant to Article 13(1) RPBA.

1.6 In view of the above, the Board considers that the filing of the operative main request as auxiliary request 2 with letter of 9 August 2016 constituted a bona fide reply to the issues identified in the Board's communication of 22 July 2016 regarding inter alia the admission to the proceedings of the then pending main request or the issue of sufficiency of granted claims 2-3 (see sections 6.2 and 7.5 of said communication).

1.7 For those reasons, the main request was admitted to the proceedings pursuant to Article 13(1) RPBA.

2. Sufficiency of disclosure

2.1 In order to meet the requirements of sufficient disclosure, an invention has to be disclosed in a manner sufficiently clear and complete for it to be carried out by the skilled person, without undue burden, on the basis of the information provided in the patent specification, if needed in combination with the skilled person's common general knowledge. This means in the present case that the skilled person should be in particular able to carry out a method according to claim 1.

2.2 Total surface moisture level

The method according to operative claim 1 comprises three steps (a) to (c) and, in order to carry out step (b), the skilled person has to be able to prepare an appropriate filler as defined in step (a), which is in particular defined in that it is produced by treating particles of an inorganic filler with a surface treatment agent under conditions such that it has a "total surface moisture level" comprising moisture adsorbed on the particles and trapped within the hydrophobic coating thereon of not greater than 0.1% by weight based on the dry weight of the inorganic particulate material". In that respect the patent in suit teaches that such a moisture level may be obtained by using an inorganic filler having a very low level of moisture and coating said inorganic filler with a specific class of hydrophobic compound while taking care not to introduce moisture during said treatment (paragraphs 40 to 46 of the patent in suit).

2.2.1 The opponents argued that the information provided by the patent to determine the "total surface moisture level" specified in claim 1 was not sufficient to prepare reliably a filler according to step (a) and, thus, to carry out the invention.

2.2.2 The parties in particular disputed how the term "total surface moisture level" was to be read and the opponents argued that that term was so ambiguous as to amount to insufficiency in the sense of Article 83 EPC.

a) In that respect, it was not contested by the patent proprietor that no definition of that term is provided in the patent in suit. Nor was it shown to have an accepted definition in the art. Also, from the wording of the claim itself, it is not clear whether or not the "total surface moisture level" is limited to the moisture "adsorbed on the particles and trapped within the hydrophobic coating" as indicated in claim 1. In that respect, the presence of the term "comprising" in claim 1 does not seem to support the latter interpretation and it was disputed by the parties if e.g. crystallisation water was comprised in the "total surface moisture level".

According to standard practice, in opposition proceedings, when a claim contains a feature which has an ambiguous meaning, as in the present case for the reasons indicated in the preceding paragraph, the wording of that claim should be read in a technically sensible way and taking into account the whole disclosure of the patent specification.

In that respect, various terms are used in the patent in suit in respect of moisture level, such as "total surface moisture level", "surface moisture level", "adsorbed water"/"adsorbed water content", "moisture adsorbed on the particles" or "adhered surface moisture" (see e.g. paragraphs 11, 13, 20, 21, 29, 40, 42, 43, 45, 48, 53, 84, 86, 87, 92; Table 2; Fig. 2). However, the gist of the invention is, as may in particular be derived from page 3, lines 18-23 and page 5, lines 11-17 of the patent in suit, to minimise the amount of water evolving from the surface treated inorganic filler prepared according to step (a) according to claim 1 during the production of breathable films according to step (c) of claim 1 in order to reduce the amount of defects (macroscopic voids) in the films so produced. In view of that problem, the skilled person would understand that the critical water content is the amount of water evolving from the particulate filler upon compounding to a film.

With that in mind, it is further noted that the invention is in particular illustrated in the patent in suit by various samples of example 1 in which the amount of "adsorbed water" is measured by Karl Fischer titration and heating the samples at 195 °C (paragraph 86; Table 2). Further, according to paragraph 53 of the patent specification a Karl Fischer titration apparatus may be used to determine the "surface moisture level" of a filler. Also, the conclusion drawn in paragraph 91 indicates that the wording "surface moisture level" and "adsorbed water" are used as equivalent in the patent in suit and further makes a direct correlation between the minimisation of the "surface moisture level"/"adsorbed water" and the reduction of voids in the films produced using the coated fillers. In view of those passages of the patent specification, it may further be concluded that the terms "total surface moisture level" (claim 1), "surface moisture level" (claim 18) and "adsorbed water" (example 1, samples 1-11) are used interchangeably i.e. those terms have the same meaning in the patent in suit. Besides, it is also taught that that moisture level may be determined by e.g. Karl Fischer titration and heating the samples at 195 °C.

In view of the above, the Board came to the conclusion that the "total surface moisture level" according to claim 1 is to be read as the amount of water evolving from the particulate filler upon compounding to a film, which may be achieved by heating the samples at 195 °C in order to simulate the temperature conditions encountered during preparation of a film and measuring by Karl Fischer titrimetry the amount of water evolved.

2.2.3 During the proceedings, the opponents contested that the Karl Fischer titration method mentioned in the patent in suit was sufficiently disclosed.

a) In that respect, it is correct that the information regarding the Karl Fischer titration method and how to carry it out provided in paragraphs 54-57 of the patent in suit teaches that "the sample is added to a pyridine-methanol solution" and no reference to any temperature is given. However, that expression is to be found in paragraph 55 that merely explain in general terms the Karl Fischer titration, as can be seen from the wording "In coulometric Karl Fischer titration, the sample is added to a pyridine-methanol solution", the rest of the sentence explaining the chemistry of the titration.

b) Considering that the Karl Fischer titration method is intended to be used to determine the amount of moisture that evolves from a coated filler during the production of a thermoplastic film, which requires that the sample to be tested is heated at 195 °C (see above), it is obvious for the skilled reader that Karl Fischer titration cannot be performed at room temperature directly on the coated particles before the heating step necessary to have moisture evolving from the coated particles has been carried out.

c) Moreover, regarding the issue of the temperature, it was indicated by the patent proprietor, in particular during the oral proceedings before the Board, that the method indicated in paragraphs 55-57 of the patent in suit, which comprises placing a sample in a pyridine-methanol solution obviously cannot be performed at 195 °C in view of the use of those organic solvents. The Board is convinced, as explained by the patent proprietor, that the skilled person considering the goal of the measurement, i.e. determining the amount of water evolving at 195 °C from the coated particles and the principle and chemistry of the well known Karl Fischer titration as briefly explained in paragraph 55 of the patent in suit, would understand that the water vapour evolving from the heated coated particles would have to be transferred as a "sample" (using the wording of paragraph 55 of the patent in suit) to the measuring Karl Fischer unit, for example by known means such as a nitrogen stream. Furthermore, no evidence has been submitted by the opponents to refute that argument put forward by the patent proprietor both during the oral proceedings before the Board and during the opposition proceedings (see minutes of the oral proceedings before the opposition division: page 2, end of the second paragraph). Consequently, the opponents have not discharged their burden of proof that the skilled person would not be in a position to determine the "total surface moisture level" according to step (a) of claim 1 on the basis of the information provided in the patent specification in respect of the Karl Fischer titration method in combination with the skilled person's common general knowledge.

2.2.4 Although the opponents argued that different ways of performing a Karl Fischer titration could be contemplated, they neither showed that such methods would lead to significantly different results in terms of "total surface moisture level" nor why that alleged ambiguity would amount to a lack of sufficiency of disclosure. Under such circumstances, said objection can at most be related to an alleged lack of clarity pursuant to Article 84 EPC, which is not a ground of opposition and which may not be raised at the present stage of the proceedings (appeal on an opposition) since that parameter is present in the granted claims (G 3/14).

2.2.5 Should water of crystallisation be present in the filler, as argued by the opponents, there is no evidence on file that it would not be taken into account after heating the sample and measurement by a Karl Fischer titration method as taught in the patent in suit. Therefore, that argument did not convince.

2.2.6 For those reasons, the opponents' objections regarding a lack of sufficient disclosure related to the term "total surface moisture level" in claim 1 is rejected.

2.3 Alleged lack of technical guidance

2.3.1 The opponents argued that the patent in suit did not provide sufficient technical guidance in order reliably to carry out the method according to claim 1.

2.3.2 However, information in respect of the working conditions to be used in the methods claimed e.g. drying temperature, time period, humidity to prepare the required reduced moisture level is provided in paragraphs 33-52 of the patent in suit.

2.3.3 In paragraphs 37-38 of the patent in suit it is in particular indicated that when a wet grinding process is employed to produce the filler of the invention, the amount of hydrophilic dispersant should be controlled.

2.3.4 It is further explained in paragraphs 40-46 of the patent in suit that the filler may be dried in one or two heating steps, whereby the first heating step may be by direct or indirect heating means while the second heating step may suitably carried out by indirect heating means (end of paragraph 40). As may be derived from paragraph 45, direct heating systems can add to the moisture content of the filler and is, therefore, less preferred.

2.3.5 The teaching of the description in respect of the amount of hydrophilic dispersant and direct/indirect heating is further confirmed by example 1 of the patent in suit. In that example, 11 samples of stearic acid coated calcium carbonate were prepared under various conditions. Sample 5, which is the sole example having an amount of adsorbed water according to claim 1 (Table 2) was wet ground with zero residual dispersant, flash dried and indirectly heated and coated (Table 1). All other samples, which were either carried out with an amount of hydrophilic dispersant not according to the preferred teaching of the patent in suit (samples 1-4, 6-8 and 11; paragraph 38; Tables 1-2) and/or with direct heating (samples 6-10; Table 1), did not exhibit an amount of adsorbed water according to claim 1 (Table 2). In paragraphs 91 and 93 of the patent in suit it is further explicitly concluded that those results show that there is a good correlation between reducing both the dispersant level and surface moisture level.

2.3.6 In view of the above, it is concluded that the patent in suit provides sufficient guidance regarding the method to be used to prepare reliably a coated filler having a "total surface moisture level" of not greater than 0.1 % by weight as indicated in claim 1, in particular regarding the fact that it may be important to control both the amount of residual hydrophilic dispersant and the manner of heating the filler in step (a) of the method defined in claim 1.

2.3.7 For those reasons, the opponents' objections regarding a lack of technical guidance is rejected.

2.4 Hydrophobic coating

2.4.1 The opponents argued that the patent in suit was insufficiently disclosed because it did not define when a coating was "hydrophobic".

2.4.2 However, it is specified in claim 1 that the coating is produced "by reaction with a hydrophobising surface treatment agent comprising one or more aliphatic carboxylic acids having at least 10 chain carbon atoms" and it is indicated in paragraphs 31-32 of the patent in suit that such a surface treatment is known in the art, which was not contested by the opponents. Further information in that respect, in particular regarding the treatment method and the nature of the hydrophobic agents, is also provided in paragraphs 31-32 and 47-48 of the patent in suit.

2.4.3 Hydrophobicity is known in the art as being the property of a material to repel or fail to mix with water (in opposition to hydrophilicity). This is also the meaning in the patent in suit as can be derived e.g. from paragraph 48. In that respect, it is noted that it is also opponent 1's understanding of that term, as is derivable from the conclusion drawn in D24 (last two sentences on page 3) according to which a coating was not "hydrophobic" because it was completely wetted by water droplets. In view of the above, the opponents' objection can only be related to the question if the skilled person knows when a coating is or is not "hydrophobic", i.e. if he is working within or outside the scope of the claims, which is, in the present circumstances of the case, at most an issue of clarity pursuant to Article 84 EPC but not of sufficiency of disclosure.

2.4.4 The question whether or not sufficient hydrophobicity is necessary "for the purpose of the invention", as argued by the opponents, is at most related to the question of which technical problem can be considered to be solved over the whole scope of the claims, e.g. also for small amounts of treatment agent, which is an issue of inventive step pursuant to Article 56 EPC, not of sufficiency in the sense of Article 83 EPC.

2.5 Under those circumstance, the objections of lack of sufficient disclosure submitted by the opponents against claim 1 of the main request did not succeed.

2.6 In view of the conclusion drawn in section 2.2.3.a above, the Board is further satisfied that also claim 18 of the main request is sufficiently disclosed.

3. Novelty

3.1 The opponents objected that the subject-matter of operative claim 1 was not novel over example 1 of D17, as well as over D3 and D1.

3.2 Example 1 of D17, respectively of WO 98/02610

3.2.1 D17 is a Canadian patent application published in 2006 and is not a valid prior art pursuant to Article 54 EPC. However, as can be seen from the third page of D17, that Canadian application is a copy of international application WO 98/02610, which was published on 22 January 1998 and which is a valid prior art according to Article 54(2) EPC. Therefore, the following analysis, although it is based on D17, would be valid when referring to WO 98/02610. That conclusion was adhered to by the patent proprietor during the oral proceedings before the Board.

3.2.2 Example 1 of D17 deals with the preparation of a breathable film made from a thermoplastic composition of two polyethylenes comprising as filler "English China Supercoat**(TM) calcium carbonate (CaCO3) coated with 1% stearic acid and obtained from ECCA Calcium Products, Inc. in Sylacauga, Alabama, a division of ECC International" (D17: page 25, lines 11-15).

3.2.3 The sole issue in dispute between the parties was whether or not the specific calcium carbonate disclosed in example 1 of D17, namely Supercoat, exhibits a total surface moisture level of not greater than 0.1 % by weight as specified in operative claim 1.

3.2.4 In that respect, it was agreed by the parties that D17 makes no reference to that parameter.

3.2.5 It was not contested by the patent proprietor that D18, which bears no publication date, was a valid prior under Article 54(2) EPC, as may be derived from D18A (published in 1993 and which contains further passages of the same book as D18).

3.2.6 D18 contains information about the product Supercoat Calcium Carbonate of ECC America Inc.. It is in particular indicated therein that Supercoat is a coated material and two tables entitled "Typical Physical Characteristics" and "Typical Chemical Analysis" are given. The following indication is in particular given in the Table "Typical Chemical Analysis": "Moisture: 0.1 max.". The issue in dispute between the parties was whether said moisture level is related to the coated or the uncoated filler.

a) In that respect, it is noted that the Table "Typical Chemical Analysis" of D18 makes no reference at all to stearic acid, which is however, according to D17, used as surface treatment agent in an amount of 1 wt.%. It is also noted that all components listed in said Table add up to make 99.6 wt.%. It does not appear plausible that a typical chemical analysis, given with a precision of up to two decimals for certain components, would not mention a component present in an amount of 1 wt.%.

b) The opponents' argument according to which it is usual to eliminate the coating before doing the chemical analysis of a filler is not supported by any evidence and cannot be retained by the Board. Nor does it appear convincing that a chemical analysis made after elimination of said coating could indicate the water content of the coated filler as it is unknown whether the step of removing the coating would remove or add any water to the uncoated filler.

c) In view of the above, it cannot be concluded in the light of D18 alone that the moisture level mentioned in D18 mandatorily refers to the coated filler.

3.2.7 The opponents' argumentation was further based on D31, the admission into the proceedings of which was contested by the patent proprietor.

a) D31 was filed with opponent 2's rejoinder to the statement of grounds of appeal, i.e. pursuant to Article 12(2) RPBA. It was further filed in support of opponent 2's argumentation in respect of novelty and in reply to the arguments put forward in the patent proprietor's statement of grounds of appeal. Under such circumstances, there is no reason for the Board not to admit D31 to the proceedings pursuant to Article 12(4) RPBA.

b) D31 is a telefax from the company VIE Americas, Inc. to opponent 2 comprising a specification for a material "calcium carbonate Supercoat". Said specification comprises among others two tables entitled "Typical Physical Characteristics" and "Typical Chemical Analysis", both of which contain exactly the same data as those listed in the corresponding tables of D18. However, in D31, several data listed in the Table "Typical Physical Characteristics" are explicitly indicated (with a "*") to refer to the properties before surface treatment, i.e. to the properties of the uncoated material, indicating that some of the properties indicated in D31 are not necessarily those of the coated material. Considering that the values of the typical physical characteristics and the typical chemical analysis indicated in D18 and D31 are identical, it cannot be concluded in view of the indication in D31 that some of the values refer to the uncoated filler that the values provided in D18 refer to the contrary to those of the coated filler.

c) The fact that for another filler, namely Kotamite, it is explicitly indicated elsewhere in the same book (D18A: page 154) that the pH of the slurry is that for uncoated material is not sufficient to provide an unambiguous indication that the other data should be considered to be those of the coated filler, and therefore that it would be the case for the coated filler disclosed in either D18 or D31.

d) The fact that telefax D31 contains a mention indicating that the datasheet contained therein is a product specification of Supercoat which is known to be a coated filler is, in the Board's view, also not sufficient to remove the doubts arising from the direct comparison of the properties of Supercoat contained in D18 and D31.

e) In view of the above, the comparison of D18 and D31, even when taking D18A into account, does not allow to conclude that the moisture level mentioned in D18 mandatorily refers to the coated filler.

3.2.8 During the oral proceedings before the Board, opponent 1 drew the attention of the Board to the fact that ECC America Inc., which is the company indicated in D18 in reference to Supercoat, is in fact opponent 1's former company name and that opponent 1 confirmed that the chemical analysis given in D18 was that of the coated material.

However, that statement is not supported by any corroborating evidence and is, thus, insufficient to convince the Board.

3.2.9 In view of the above and considering the information contained in D18, D18A and D31, it cannot be concluded that the moisture content disclosed in either D18 or D31 is related to the coated filler. Under such circumstances, it was not shown that the filler Supercoat used in example 1 mandatorily has a moisture content of "not greater than 0.1 wt.%" according to operative claim 1.

3.2.10 Whereas the patent proprietor requested that D23, which had not been admitted to the proceedings by the opposition division, be admitted to the proceedings by the Board, opponent 2 specifically requested during the oral proceedings before the Board that D23 should not be admitted to the proceedings. However, considering that it was neither shown nor argued by the opponents that D23 contained any information that would refute the conclusion drawn above in the light of D18, D18A and D31, D23 is not relevant for the present decision and was not admitted into the proceedings by the Board (Article 12(4) RPBA).

3.3 Document D3

3.3.1 D3 discloses films comprising a microporous core layer containing at least a thermoplastic polymer and a particulate filler (claim 1, layer B).

3.3.2 The particulate fillers which may suitably be used to make the micropores are listed from page 12, line 11 to page 13, line 10, of which calcium carbonate is indicated as the preferred material (last sentence of the above passage). No mention is made in that section of coated particulate fillers.

3.3.3 The formation of micropores is explained on pages 18-19 of D3, in which it is taught that the amount of water and/or volatiles in the material to be processed should be reduced in order to avoid foaming or large holes in the films (page 18, lines 25-29). Regarding water, it is further mentioned that it is known that the thermoplastic resins used for making the films are usually hydrophobic and do not release water upon processing but that this is not the case for hydrophilic particulate fillers such as calcium carbonate (page 18, line 31 to page 19, line 3). Regarding volatiles, it is further indicated that a known source is the coating typically present on particulate filler such as stearic acid which is typically used to coat calcium carbonate (page 19, lines 8-11). In that case, D3 discloses that the amount of volatiles released from the coating may be controlled by degassing the mineral during compounding. Such a methodology is indeed known in the art as indicated in paragraph 10 of the patent in suit. However, such a method is a post-treatment of the coated filler during the film production and does not correspond to the sequence of process steps (a) and (b) according to operative claim 1, which define that the inorganic filler is first coated under conditions such as to achieve a moisture level of not greater than 0.1 wt.% and subsequently mixed to the thermoplastic polymer.

3.3.4 On page 19, lines 17-22 and 25-34 of D3 it is further explained that the amount of water and/or volatiles in the starting materials should be sufficiently low to prevent the formation of large holes and that it should suitably be between 100 ppm and 500 ppm. However, said passage is not specifically directed to coated fillers, in particular not to the calcium carbonate coated with stearic acid mentioned earlier at page 19, lines 8-16 of D3. In that respect it is noted that the fillers listed in D3 (see section 3.3.2 above) and used in the examples of D3 (page 23, line 5) are not specifically surface coated. Besides, the indication "a suitable total volatile content for the particulate filler has been found to be between about 100 ppm and about 500 ppm" (page 19, lines 30-33), although it may be held as indicating a preferred embodiment of D3, it does not constitute a mandatory feature which must apply to all embodiments of D3. In particular, it cannot be concluded that the teaching of D3 in its whole imposes a maximum amount of 500 ppm volatiles and/or water for any embodiment illustrative of the invention of D3. Therefore, it cannot be concluded that D3 directly and unambiguously discloses the combination of said range of 100-500 ppm water and/or volatiles for the calcium carbonate surface coated with stearic acid disclosed on page 19, lines 8-16 of D3.

3.3.5 For those reasons, D3 fails to disclose directly and unambiguously the combination of features according to steps (a) and (b) of the method according to operative claim 1.

3.4 Document D1

3.4.1 a) D1 is an "E" document (priority older than the priorities of the patent in suit but published after the international filing date). Therefore, D1 can only be taken into account for novelty if the novelty destroying subject-matter is supported by the priority document of D1. In the present case, the sole subject-matter susceptible to be novelty destroying consists in the examples in which a film is made. However, said subject-matter is not supported by the priority of D1. D1 may not anticipate the subject-matter being claimed.

3.4.2 Besides, it was not shown by the opponents that D1 explicitly discloses the "total surface moisture level" feature according to operative claim 1. Nor was it indicated which subject-matter of D1 was held to disclose directly and unambiguously the specific combination of features according to operative claim 1 (at least 10 carbon atoms; thermoplastic polymer; breathable film).

3.4.3 Those conclusions, which were already drawn in the Board's communication, were not contested by the opponents, in particular not during the oral proceedings before the Board.

3.5 In view of the above, the opponents' novelty objections in respect of each of D17, D3 and D1 are rejected.

4. Remittal

The issue of inventive step was not addressed in the contested decision. Further considering that all parties requested remittal to the first instance, it is appropriate to remit the case to the department of first instance for further prosecution (Article 111(1) EPC).