T 0091/18 05-05-2021

Main request

1. Admittance

1.1 D30 is an excerpt of a textbook about polyurethanes providing, according to the appellant, information on the relation between the open cells of the polyurethane and the control of the urethane reaction (statement setting out the grounds of appeal, section I.3, page 3). It appears that D30 was filed in direct reply to the reasoning of the opposition division regarding the absence of a link between the urethane reaction and the open cells content in the resulting polyurethane in point iii) bridging pages 17 and 18 of the contested decision. In view of that and taking into account that the admittance of D30 was not contested by the respondent, the Board finds it appropriate to admit D30 into the proceedings.

1.2 Two sets of supplementary examples were provided by the respondent in appeal, the first set with the reply to the statement setting out the grounds of appeal (examples 4 and 5) and the second set with letter of 28 November 2018 (examples 6-8). The admittance of these two sets of examples was contested in the written phase of the appeal by the appellant but that objection was withdrawn at the oral proceedings before the Board. Since the two sets of examples can be seen as having been filed in reply of the argument of lack of inventive step made in the statement setting out the grounds of appeal (point II.2.8 on page 6 and point V.2.12 on page 37) and taking into account that the admittance was no longer contested by the appellant, the Board finds it appropriate to admit the two sets of examples into the proceedings.

1.3 The statement of grounds of appeal contained an objection of lack of inventive step against claim 1 of the main request in view of D1 as the closest prior art. The admittance into the proceedings of that objection was contested on the grounds that it had not been part of the proceedings up to its filing with the statement setting out the grounds of appeal.

1.3.1 In that regard, it was not contested that that objection had not been raised in the written proceedings before the opposition division. While the minutes of the oral proceedings before the opposition division indicate that the opponent mentioned that in principle D1 could be considered as the closest prior art (section 7.1), there is no indication that the parties were heard on an objection of lack of inventive step starting from document D1, nor that its admittance into the proceedings was even requested and discussed at the oral proceedings. On that basis, the Board cannot conclude that the objection of lack of inventive step starting from D1 was admitted into the proceedings by the opposition division at the oral proceedings. This is supported by the fact that the objection of lack of inventive step in view of D1 is not addressed in the decision under appeal and was not decided upon.

1.3.2 It follows therefrom that the admittance of the objection of lack of inventive step starting from D1 is subject to the Board's discretion under Article 12(4) RPBA 2007 (which applies by virtue of Article 25(2) RPBA 2020). In this respect the Board considers that, if the opponent intended to attack the patent on that basis, they should have raised the objection in full in the opposition phase since D1 was submitted at the outset of the opposition proceedings and the objection of lack of inventive step in view of D1 was not shown to result from a later change in the opposition proceedings. In the absence for a justification to file the new objection in appeal, the Board finds it appropriate to exercise its discretion pursuant to Article 12(4) RPBA 2007 by not admitting the objection of lack of inventive step starting from D1 into the proceedings.

2. Sufficiency of disclosure

2.1 Sufficiency of disclosure in appeal was objected in view of the definitions, in claim 1, of the metals derived from a composite metal cyanide complex catalyst, of the phosphoric acid compound and of the polyether polyol which allegedly created uncertainties as to how the presence of metals and the phosphoric acid compound could be ensured and measured during the preparation of the polyurethane foam.

2.2 With regard to the questions raised by the appellant concerning the operation of the process, since they were not based on verifiable facts, they are not sufficient to establish that a skilled person would have had serious doubts as to how the process according to operative claim 1 could be performed using the common general knowledge in the field of polyurethane foams.

2.3 As to the presence, in a claim, of vague terms, it is a well-established principle laid down by the case law that a non-specific definition in a claim should be given its broadest technically sensible meaning (Case Law of the Boards of Appeal, 9th Edition, July 2019, I.C.4.1, page 113, fourth paragraph). A vague or unspecific term used in the definition of essential features in a claim is however not in itself a sign of lack of sufficiency.

2.4 In particular, the lack of specification of the nature of the metals in "metals derived from a composite metal cyanide complex catalyst" only means that any metal of a DMC catalyst falls under the definition provided in claim 1. Metals of composite metal cyanide complex catalysts are known in the art and can also be identified in paragraph 24 of the patent in suit. The lack of specificity of claim 1 in that regard does not lead to the conclusion of a lack of sufficiency of disclosure.

2.5 As to the phosphoric acid compound, the limitation in claim 1 is that it is present in an amount of 0.5 to 100 ppmw during the blowing reaction. While consumption of the phosphoric acid compound prior to the blowing reaction is not excluded from the process of operative claim 1, it is also not excluded that its amount can be adjusted to be 0.5 to 100 ppmw during the blowing reaction. In that regard, it has not been shown that consumption of the phosphoric acid compound prior to blowing could not be accounted for by a skilled person with help of the common general knowledge.

2.6 As to the objection regarding the lack of a measurement method of the amounts of metals and phosphoric acid compound in the patent in suit, the respondent pointed at several general methods that are part of the common general knowledge (rejoinder, passage bridging pages 3 and 4). While these measurement methods may not have the same accuracy, it was not shown that a possible lack of accuracy would have prevented the skilled person from performing the process of operative claim 1. In that regard, if there was a lack of accuracy of the determination of the amounts of metals and phosphoric acid compound, that would at most amount to a lack of clarity but not to a lack of sufficiency of disclosure.

2.7 With regard to the definition of operative claim 1 by reference to one polyether polyol only, it is recalled that a claim must be read based on its wording and how this is understood by the skilled person. In the present case the formulation chosen clearly means that one polyether polyol must satisfy the conditions laid out for the process. While the presence of other polyether polyols is not excluded, the requirement is that at least one of these polyether polyols is such that the conditions set out in operative claim 1 are fulfilled.

2.8 As to the question about the lack of a method to remove any composite metal cyanide complex catalyst from the polyether polyol used in operative claim 1, it must be emphasized that the preparation of the polyether polyol is not part of operative claim 1. It is thus irrelevant for the process claimed how the polyether polyol was prepared.

2.9 Under these circumstances, the Board concludes that the claims of the main request are sufficiently disclosed.

3. Novelty

3.1 The main request submitted with the reply to the statement setting out the grounds of appeal is based on the claims of the patent as granted in which claims 8 and 9 were deleted. It follows that the objections of lack of novelty of claims 8 and 9 raised in the statement of grounds are not relevant to the present set of claims as acknowledged by the appellant in their letter of 13 March 2019 (page 3, point II). There are no further objections against novelty of the claims of the main request.

4. Inventive step

4.1 The appellant considered in the statement setting out the grounds of appeal that any of D2, D14a or D21 could be seen as representing the closest prior art (as to D1 as the closest prior art see the conclusion on admittance of the objection in point 1.4.2, above).

4.2 D21

4.2.1 D21 was seen by both parties as a relevant document to be taken as the closest prior art for operative claim 1. D21 relates to a process for producing a flexible polyurethane foam which comprises reacting a polyol mixture comprising polyols (A) and (B) with a polyisocyanate compound in the presence of a urethane-forming catalyst and a blowing agent (claim 1). D21 discloses in paragraph 12 that the flexible polyurethane foams obtained by that process have, among other properties, excellent air flow and no irregular cell structure, which was accepted by both parties as being a display of their good open cell structure in the sense of the patent in suit. The Board thus agrees with the parties that D21 is a reasonable document to be taken as the closest prior art for operative claim 1.

4.2.2 The process of examples 1-3 of D21 was chosen as the most relevant starting point within D21. These examples, which are summarized in Table 1 on page 16, disclose the preparations of polyurethane foams from a polyisocyanate and a mixture of polyols of type (A) and (B), whereby the polyol mixtures contain metals from a DMC catalyst in total amounts of 2.1 ppm (Example 1), 10 ppm (Example 2) and 2.73 ppm (Example 3) originating from polyols A1 (paragraph 88) and A2 (paragraph 89). The presence of a phosphoric acid compound during the reaction of the polyisocyanate and the polyol mixture is not disclosed in D21.

4.2.3 In view of this it was acknowledged by the parties in appeal and it is shared by the Board that the process according to operative claim 1 differs from the process of examples 1-3 of D21 in the presence of 0.5-100 ppmw of a phosphoric acid compound in the course of the polymerization of the polyisocyanate with the polyol(s).

4.2.4 Starting from examples 1-3 of D21, it has to be determined whether the evidence made available in appeal, including the examples of the patent in suit and the supplementary examples 4-8 provided with the rejoinder of the respondent and with their letter dated 28 November 2018, allowed a fair comparison with the process of D21 such that it could be established that an effect was causally linked to the distinguishing feature of the process of operative claim 1.

4.2.5 The process of the examples of the patent in suit and that of examples 1-3 of D21 are however not comparable because they are based on different polyols. The polyol used in the process of the patent in suit that was also used in the supplementary examples 4-8 is disclosed in paragraphs 59-65 of the patent. That polyol, named polyol X, is obtained by polymerization, in the presence of a DMC catalyst and glycerol as an initiator, of ethylene oxide and propylene oxide (paragraph 61). The polyol used in the process of examples 1-3 of D21 differs from polyol X of the patent in suit in that it is a mixture of distinct polyols (A1) or (A2) with (B1) and (B2) all polyols being based on propylene oxide only and obtained with a different catalyst and initiator (paragraphs 88, 89, 95 and 96). That difference is meaningful as D21 teaches in its paragraph 58 that the air flow of the produced foams depends on the proportion of the polyols (A) and (B) in the polyol mixture. Since none of the examples or comparative examples put forward by the respondent discloses a process relying on a polyol according to D21, the evidence provided cannot establish that the open cell content of the foams produced by the process according to operative claim 1 was improved over that in D21.

4.2.6 The evidence made available however shows that all other process parameters being equal, the use of 0.5-100 ppmw of phosphoric acid compound has an effect on the open cell content of the produced foams, as seen by the decreasing porosity values in mm EtOH with increasing amounts of phosphoric acid compound present (Table in paragraph 70 of the patent in suit and Table of the supplementary examples). While an improvement in absolute terms with respect to D21 cannot be acknowledged, it must be recognised that the addition of a phosphoric acid compound provides an alternative way to obtain high open cell content.

4.2.7 The problem that can be formulated in view of that evidence and of D21 is thus the provision of an alternative way of providing polyurethane foams with a high open cell content.

4.2.8 With regard to obviousness and the submissions of the appellant in this respect, the question is whether D1 or D2 read in the context of the common general knowledge represented by D30, suggests the use of 0.5-100 ppmw of a phosphoric acid compound as a possible means for providing polyurethane foams having high open cell contents.

4.2.9 D30 is a textbook on polyurethanes and can be accepted to represent the common general knowledge in the field of polyurethanes. In particular it concerns the preparation of polyurethane foams by a process in which a polyether polyol and a polyisocyanate are reacted (the urethanization reaction) in the presence of a blowing agent (sections III and IV of D30). Section IV and in particular the part on pages 249-253 of D30 teaches that the catalysts used in the reaction can influence the ratio of open to closed cells in the foam. The second paragraph on page 252 in particular teaches that closed cells can be reduced by reducing the amount of tin catalyst that is involved in the isocyanate-hydroxyl reaction or that the open cell content can be increased by increasing the tin catalyst or reducing the amine catalyst. That teaching however is specific to the amine and tin catalysts. While this teaching could have been applied to the corresponding amine and tin catalysts that are already present in the process of examples 1-3 of D21 (catalyst a in Table 1 is the amine catalyst of paragraph 106 and catalyst d is the tin catalyst of paragraph 107), it provides no reason to consider the use of a phosphoric acid compound, which is not even mentioned in that document. In particular there is no indication in D30 of how the addition of a phosphoric acid compound would influence the formation of cells in a process involving amine and tin catalysts.

4.2.10 D1 in its turn discloses the preparation of polyether polyols by ring opening polymerization of an alkylene oxide in the presence of a DMC catalyst (paragraph 12) and the subsequent preparation of a polyurethane (paragraph 13) by reaction of that polyether polyol with a polyisocyanate in the presence of 0.5-100 ppmw of a phosphoric acid. D1 teaches in paragraphs 15, 37 and 47/48 that, while control of the reaction is difficult due to the presence of metal residues from the DMC catalyst, the addition of 0.5-100 ppmw phosphoric acid, which acts as an inhibitor, permits to control the reaction rate of the urethanization reaction and produce a polyurethane having high storage stability. D1 however does not concern the production of foams so that it is unclear to which extent the teaching of D1 could have been applicable to the preparation of polyurethane foams. In particular, there is in D1 no indication that the addition of a phosphoric acid compound as an inhibitor of DMC catalysts in polyols would be compatible with the process for the production of polyurethane foams of D21, which is performed in the presence of further catalysts such as an amine and a tin catalyst, and suitable to provide high open cell contents. A different conclusion cannot be reached also when considering the teaching of D1 in the light of D30, as, even having in mind the effect of the tin and amine catalyst contents on the open cell rate as taught in D30, the skilled person would have no reason to employ a phosphoric acid compound as inhibitor of the DMC catalyst according to the teaching of D1 in the expectation of obtaining a similar effect on the open cell formation. D1 therefore does not lead to the subject-matter of operative claim 1 also taking into account the teaching of D30.

4.2.11 D2 is a collection of several technical publications concerning Acclaim polyols. The second article in particular concerns the role of acidification in urethane prepolymers. That article pertains to specific polyols Acclaim DP4220 and DP6320, which are said to have such a high reactivity that their use to produce prepolymers requires the addition of a e.g. 20 ppm phosphoric acid (second page of D2, third column). There is however no apparent reason why the skilled person would have applied that teaching which concerns the production of prepolymers to the production of polyurethane foams and the control of cell opening of these foams. Therefore also D2 does not lead to the subject-matter of operative claim 1.

4.2.12 In view of these reasons the board comes to the conclusion that the process of operative claim 1 involves an inventive step when starting from document D21 as the closest prior art.

4.3 Referral to the Enlarged Board of Appeal

4.3.1 In the context of the analysis of inventive step with respect to document D21, the appellant requested a referral of a question to the Enlarged Board of Appeal should the Board conclude that the data forming the basis of the discussion of inventive step show an improvement in view of the closest prior art. The question related to the formulation of the technical problem in a specific situation of the patent in suit in view of the closest prior art and the evidence of an effect on file.

4.3.2 In particular, the question was to determine whether, in case an applicant or patent proprietor in order to establish inventive step over the closest prior art relied on a technical effect that was also achieved in the prior art but by other means that were not excluded by the application or the patent in suit, comparative examples had to reflect the closest prior art (then using the other means) or it was sufficient to provide comparative examples which did not make use of the proposed solution of the closest prior art.

4.3.3 According to Article 112(1)(a) EPC, a Board of Appeal shall refer a question to the Enlarged Board of Appeal if a decision is required in order to ensure uniform application of the law or if an important point of law arises. The answer to the referred question should not be merely of theoretical or general interest, but has to be essential to reach a decision on the appeal in question (see, for example, G 3/98, OJ EPO 2001, 62, Reasons No. 1.2.3).

4.3.4 In the present case, the Board came to the conclusion that an inventive step could be acknowledged even if the comparative examples made available for the discussion of inventive step did not reflect the relevant starting point in the closest prior art and the presence of an improvement over that closest prior art was not acknowledged. It follows that the outcome of the present appeal does not depend on the answer to the questions formulated by the appellant. That question consequently need not be referred to the Enlarged Board of Appel.

4.3.5 The request for referral to the Enlarged Board of Appeal is therefore refused.

4.4 D14a

4.4.1 D14a (as an English translation of prior art document D14; reference in what follows in always made to D14a according to the submissions of both parties) was also considered as a relevant document to be taken as the closest prior art for claim 1 of the main request. D14a concerns the preparation of cold curing high-resilience foam plastics based on a reaction of polyether polyol with an isocyanate (claim 1) and aims at improving the open-cell rate of these foams (Specification, page 2/5, last paragraph). This problem is similar to the one addressed in the patent in suit (paragraph 6). On that basis, D14a is, objectively seen, a reasonable starting point for an assessment of inventive step of claim 1 of the main request.

4.4.2 The disclosure within D14a that comes closer to the process of operative claim 1 is that of embodiment 1, which concerns a process for the preparation of polyurethane foams in two steps. The first step of that process concerns the preparation of a modified MDI (called component B) during which 10ppm of phosphoric acid is present as a polymerization inhibitor. The first step is followed by a second step being the reaction of that component B with a high-resilience compound material (component A). Since it cannot be derived from D14a that the whole phosphoric acid present is fully consumed in the first step, it is reasonable to assume that some phosphoric acid may be present in the second step of embodiment 1, albeit in an amount that is not further disclosed in D14a. Annex D was referred to by the appellant in this respect . However, the calculations made in that annex are based on the assumption that the phosphoric acid present in the first step is present in the same amount in the second step, which is not derivable from D14a. No mention is made in D14a of the presence of metals in the reacting system.

4.4.3 It follows that the process of operative claim 1 differs from the process of embodiment 1 of D14a in i) the presence of from 1 to 30 ppmw, based on the polyether polyol, of metals derived from a composite metal cyanide complex catalyst; and in ii) the presence of from 0.5 to 100 ppmw, based on the polyether polyol, of a phosphoric acid compound comprising a phosphoric acid selected from orthophosphoric acid, polyphosphoric acid and polymetaphosphoric acid, and/or a partial ester of such a phosphoric acid.

4.4.4 There is no comparative examples in the patent in suit or in the supplementary examples provided in appeal which can be taken as representative of the process of embodiment 1 of D14a. Moreover no relevance was given by the respondent to the presence of metals for the formulation of a technical problem. In view of the same considerations as detailed in the analysis starting from document D21 (see point 4.2.5 to 4.2.7, above), the problem remains the provision of an alternative way of providing polyurethane foams with a high open cell content.

4.4.5 Regarding the presence of a phosphoric acid compound in the process, the situation starting from D14a is the same as the one starting from D21. Taking into consideration the disclosures of D1 and D2 also in the light of D30, an inventive step must be acknowledged for the same reasons as detailed above (see points 4.2.8 to 4.2.12). As an inventive step is already acknowledged in view of the feature relating to the phosphoric acid compound, there is no need to analyse the further distinguishing feature.

4.5 D2

4.5.1 D2 was also considered by the appellant as a suitable document to be taken as the closest prior art.

4.5.2 D2 concerns the commercially available Acclaim polyols and in particular Acclaim DP4220 and Acclaim DP6320 for which amounts of phosphoric acid and residual catalyst were derived. While D2 briefly mentions on page 1 (first column, first paragraph) that Acclaim polyols were used to prepare polyurethanes, that document does not concern a process for the preparation of polyurethane foams. In fact, D2 does not even explicitly disclose any process to produce polyurethanes from Acclaim DP4220 and Acclaim DP6320 specifically. In that regard, D2 discusses the properties of polyols, which represent nothing more than a single component of the reaction system of the process of claim 1 of the main request, without addressing the subject of the patent in suit which is the production of polyurethane foams. Therefore D2 is not a reasonable starting point for the skilled person aiming at developing a process for preparing a polymer foam and cannot lead already for this reasons to the subject-matter of claim 1 of the main request.

4.6 The Board concludes from the above that claim 1 of the main request involves an inventive step over the prior art cited.

5. As all of the objections of the appellant against the main request of the respondent fail, the patent is to be maintained in that form.