T 0490/07 06-07-2009

1. The appeal is admissible

2. Main request

2.1 Art 123(2) EPC

2.1.1 As explained in section III above, claim 1 of the main request (i.e. corresponding to the fifth auxiliary request considered by the opposition division) defines the diol component in the following terms: "(b) from 20 to 80 mole percent of a diol component consisting of diethylene glycol and, optionally other low molecular weight diols of the formula…".

2.1.2 Independent claim 1 (product) and independent claim 15 (process) of the application as filed (reference being made to the PCT publication) specify the aliphatic diol by means of a generic formula, but do not define any specific compounds. Similarly dependent claim 4 specifies that the diol is diethylene glycol (emphasis of the Board), but the terms of this claim do not specify the presence of any other diol(s).

2.1.3 In the section of the application entitled "Aliphatic Diols" (commencing at page 11 line 18 and continuing onto page 12) various specific aliphatic diols including diethylene glycol "or any combination thereof" are listed. Thus diethylene glycol is mentioned twice, once at page 12 line 7 as one of the "Examples of suitable aliphatic diols" and once at page 12 line 15 where it is stated that "Preferred aliphatic diols are neopentyl glycol and diethylene glycol". Further all the examples employ - as the sole diol - diethylene glycol.

2.1.4 Whilst it is true, as argued by the respondent/patent proprietor that diethylene glycol was especially preferred (see section VI.(b) and IX.(a) above) - Board's emphasis - and that combinations of aliphatic diols from the list referred to above might be used, there is nothing in the list to suggest that any combination thereof must necessarily include DEG, and there is nothing in the specifically subsequently mentioned association of DEG and neopentyl glycol (which latter compound is not mentioned in the said list) to suggest that such an association could be extended to another group of diols, such as those in the list. Hence there is no disclosure of the specific selection of DEG in combination with the generality of "other low molecular weight diols of the formula …" etc, in the documents of the application as filed. Accordingly there is no explicit disclosure in either the claims or the description of the application that diethylene glycol optionally in combination with other diols may be employed as the diol component.

2.1.5 This conclusion cannot be altered by the argument of the respondent/patent proprietor that the specification of DEG in claim 1 of the main request did not amount to a selection. It is the further step of combining the DEG with other aliphatic diols and making this explicit which constitutes the selection.

2.1.6 In this connection, the expression of a preference does not render an embodiment mandatory or inevitable - it merely suggests to the skilled reader that this embodiment may exhibit particularly advantageous properties, i.e. make it obvious to employ this embodiment.

2.1.7 Whilst the respondent/patent proprietor suggested that the Board's citation of T 823/96 lacked relevance (see sections VII.(a), VIII and IX.(a), above) since it was not specifically concerned with the allowability of amendments, the point of this decision is that it deals with the question of what might be considered to be disclosed in a document even if not explicitly described therein - i.e. what might be the implicit disclosure of said document. This was not to be construed as meaning matter that did not belong to the content of the technical information provided by a document but might be rendered obvious on the basis of that content (emphasis of the decision cited). Rather in order for subject-matter that was not explicitly disclosed in a document to be considered nevertheless to belong to the technical information provided by that document, i.e. to be "implicitly disclosed" therein it was required that such matter be a clear and unambiguous consequence of that which was explicitly mentioned. The question of what might be rendered obvious by a disclosure in the light of common general knowledge was not relevant to the assessment of what was implied by the disclosure of said document. These two questions had to be strictly separated. Thus the disclosure of a number of aliphatic diols on page 12, even if stated explicitly to be preferred, at most renders it obvious to employ a particular combination of said diols. The respondent/patent proprietor has however identified no disclosure in the application as filed of which the clear and unambiguous consequence is that one or other of these diols has mandatorily to be present, regardless of which other diols are present. Thus the respondent/proprietor has failed to demonstrate that the application as filed contains an implicit disclosure equivalent to the scope of the subject-matter of feature (b) of operative claim 1. Accordingly it is concluded that there is no disclosure - implicit or explicit - in the application as filed of the feature "diethylene glycol and optionally other diols". Accordingly this feature extends beyond the content of the application as originally filed, contrary to the requirements of Art. 123(2) EPC.

2.2 For the foregoing reasons, the main request does not meet the requirements of Art. 123(2) EPC.

2.3 The main request is therefore refused.

3. First and second auxiliary requests

3.1 Art. 123(2) EPC These requests employ the same definition of the diol component (b) as the main request and consequently suffer form the same defect. This conclusion was not challenged by the respondent/patent proprietor on the occasion of the oral proceedings (see section IX.(a) above).

3.2 The first auxiliary request and second auxiliary request are therefore refused.

4. Third auxiliary request

4.1 Art. 123(2) EPC Compared to the main request, feature (b) of the third auxiliary request is restricted to diethylene glycol as the diol (see section VI above). The appellant/opponent did not raise any objection to this request pursuant to Art. 123(2) EPC (see section IX.(a) above), nor has the Board any objections of its own in this respect. As noted above, diethylene glycol is explicitly disclosed on page 12 of the application as filed as one of the diols. The effect of this amendment is to eliminate alternatives but does not generate any new combination of subject-matter (cf T 615/95, of 16 December 1997, not published in the OJ EPO, Reasons 6). The claims of the third auxiliary request therefore meet the requirements of Art. 123(2) EPC.

4.2 Art. 83/100(b) EPC The objections raised under this ground of opposition were withdrawn by the appellant/opponent (see section IX.(b) above). The Board has no objections of its own pursuant to this ground. The third auxiliary request therefore meets the requirements of Art. 83 EPC.

4.3 Art. 54 EPC Objections under this ground of opposition were not raised in the appeal procedure (see sections V.(d) and IX.(c) above), nor has the Board any objections of its own. The subject-matter of the claims of the third auxiliary request therefore meets the requirements of Art. 52(1) EPC in combination with Art. 54 EPC.

4.4 Art. 56 EPC

4.4.1 The patent in suit, the technical problem The patent in suit relates according to paragraph [0001] and claim 1 to low viscosity aromatic polyester polyols having an average functionality of about two formed by inter-esterification of a phthalic acid based material with diethylene glycol, a higher functional polyol and a hydrophobic material. It is explained that aromatic polyols are widely used in the manufacture of polyurethane and polyurethane-polyisocyanurate foams and resins. Aromatic polyester polyols are attractive since they tend to be low in cost yet can be used to produce a wide variety of cellular foams having excellent properties and adaptable for many end use applications. One class of commercially successful polyester polyols is produced by esterification of phthalic acid or phthalic acid anhydride with an aliphatic polyhydric alcohol. Such a polyester polyol is somewhat viscous and is capable of reacting with organic isocyanates to produce Coatings, Adhesives, Sealants and Elastomers ("CASE" products), that can have excellent characteristics such as tensile strength, adhesion and abrasion resistance (patent in suit, paragraphs [0002] and [0003]). One problem with aromatic polyester polyols is that they have high dynamic viscosity, making handling very difficult. They often have to be diluted or dissolved in a solvent for use (paragraph [0004]). Ideally an aromatic polyester polyol would have a dynamic viscosity that is sufficiently low to allow ease of pumping and mixing without the use of solvents or other viscosity modifiers (patent in suit paragraph [0005]). Accordingly there is a need for low viscosity aromatic polyester polyols having an average functionality of about two, that are economical to produce and can be converted into cellular foams and other CASE materials having excellent properties (patent in suit paragraph [0008]). According to the summary of the invention in paragraph [0009] of the patent in suit the invention further relates to cellular foams made from the polyester polyols. It is taught that the polyester polyols may be utilised with a wide variety of blowing agents inter alia chlorofluorocarbons. The examples of the patent in suit relate to polyester polyols having dynamic viscosities ranging from 3700 cps @ 25ºC (example 1) to 8400 cps @ RT (example 3). None of the examples in the patent in suit demonstrates the reaction product of said polyols with an organic isocyanate. Such evidence was however provided with the letter of the respondent/patent proprietor dated 4 December 2006 (see section II above). This evidence related to three polyester polyols. "Polyol A" was prepared according to example 2 of the patent in suit and had an average functionality of 2.0. "Polyol B", having an average functionality of 1.8, was prepared by modifying "Polyol A" by reaction with soybean oil to yield a polyester polyol. "Polyol C", with an average functionality of 2.2 was prepared by modifying "Polyol A" with "Voranol" (propoxylated glycerine cf paragraph [0044] of the patent in suit). Elastomers were prepared from these three polyols by reaction with diphenylmethane diisocyanate (MDI). The results, presented in the form of a graph showed that an optimum balance between tensile strength and elongation was obtained at a functionality of 2:

FORMULA/TABLE/GRAPHIC

In the light of this evidence it can be concluded that the problem as set out in paragraph [0008] of the patent in suit has been effectively solved by the claimed measures.

4.4.2 The prior art Only D1 was invoked in the statement of grounds of appeal (see section V.(e) above). D1 is directed according to claim 1 to a process for preparing a high aromatic content low acid number self compatibilised phthalate polyester polyol blend. This blend is prepared according to the claim by producing a liquid reaction product of:

- (a): at least one phthalic acid material with

- (b): at least one aliphatic diol and

- (c): at least one hydrophobic material.

The liquid reaction product is admixed with:

- (d): at least one nonionic propoxylate ethoxylate compound.

According to the section entitled "Background of the Invention" the aim of D1 is to produce polyols useful in formulating prepolymer blends for reaction with organic isocyanates to produce polyurethane and/or polyurethane-polyisocyanurate cellular polymers and in particular in the field of phthalate polyester polyols which self-compatibilize with fluorocarbon blowing agents. It is explained in the section entitled "2. Prior Art" that aromatic polyester polyols are attractive in particular in order to produce rigid cellular polymers (D1, col. 1 lines 15-20). A known commercial product has low viscosity, a high aromatic content and low acid number. Even though such product typically has a reactive hydrogen functionality of less than about 3 it catalytically reacts well with organic isocyanates to produce rigid cellular polymers having excellent properties such as compressive strength, tumble friability and burn char (D1 col. 1 lines 25-35). One problem with aromatic polyester polyols is that these are poorly compatible with fluorocarbon compounds of the type conventionally used as blowing agents to make cellular polymers (D1, col. 1 lines 36-40). Although this problem had been addressed by including a compatibilizing agent (D1, col. 1 lines 41-44) it is explained that this is however undesirable in terms of cost incurred through the additional process step required and due to the cost of the additive itself (col. 1 line 56 to col. 2 line 5). Accordingly the aim of D1 was to provide phthalate polyester polyols which were self compatibilizing with fluorocarbon blowing agents and had a combination of low viscosity, low reactive hydroxyl functionality (i.e. less than 3) and high aromatic ring content (col. 3 lines 29-37). The polyester polyols of D1 are the reaction products of the three components (a), (b) and (c) specified in claim 1 thereof. A propoxylate ethoxylate compound (d) can be dissolved in the phthalate polyester polyol blend, without causing gelation upon addition of fluorocarbon and without the need for also adding a further agent. The mixture is stated to display excellent fluorocarbon compatibility characteristics (col. 4 line 56 to col. 5 line 12). These hydrophobic compound modified phthalate polyester polyol blends form when catalytically reacted with organic isocyanates cellular foams of superior tumble friability and also superior uniform small sized cell structure (col. 5 lines 13-20). With respect to the hydrophobic compound it is taught that after formation of the polyester polyol a blend thereof can be prepared with a nonionic surfactant of the propoxylate ethoxylate type (col. 7 line 44-col. 8 line 21). Such compounds are exemplified in examples D and E of D1, namely alkoxylated glycerine and alkoxylated sucrose. Hence, as noted in the decision under appeal (see section III.(d) above) and submitted by the appellant/opponent (see section V.(e) above) these compounds correspond to those specified according to feature (c) of operative claim 1. According to the passage commencing at column 8 line 22 of D1 optionally the starting mixture (i.e. prior to reaction) can, in addition to reaction components (a), (b) and (c), contain minor amounts of other reactive components such as polyhydroxylated and polycarboxylated compounds, i.e. compounds having three or more functional hydroxyl and/or carboxyl groups. Such compounds, include inter alia 1,1,1-trimethylolpropane - TMP - which is employed in example 27 of D1 (see section III.(c), above).

4.4.3 The relationship between the patent in suit and D1 Whilst the general teaching of D1 relates, as explained above, to a reaction product of three components (a), (b) and (c) to which a fourth component (d) - corresponding to component (c) of operative claim 1 - may be added after completion of the reaction, example 27 of D1 (the final example) differs in that a fourth component - trimethylol propane as mentioned above - is present prior to the reaction forming the product. This is stated in example 27 of D1 to illustrate that triols in controlled amounts can be incorporated in a starting mixture with phthalic anhydride, diol and hydrophobic compound without producing gelation and also that the product has improved Freon solubility compared with the same product without any hydrophobic compound. Thus, whilst the subject-matter of operative claim 1 differs from that of example 27 of D1, which has been held in the decision under appeal to disclose an aliphatic polyol having a functionality of "about 2" since it was held to be novelty destroying for the subject-matter of claim 1 of the fourth auxiliary request considered by the opposition division (see section III, above), by the definition of component (c), the subject matter of operative claim 1 also differs from the general teaching of D1 in that the polyester polyols are formed by the polymerisation mandatorily of the four components recited. Although all four such components are also disclosed in D1, that corresponding to component (c) of the operative claims, i.e. the higher functional polyol (component (d) - see examples D and E of D1) is not employed as a co-reactant but is blended with the reaction product of the other 3, as explained in section 4.4.2 above.

4.4.4 The objective technical problem

(a) The evidence provided by the comparative data filed with the letter of 4 December 2006 does not correspond to the teaching of D1 since it relates to polyester polyols which are the copolymerisation product of the four components specified in operative claim 1 and specifically demonstrates polyester polyols having a functionality of around two, i.e. 1.8, 2.0 and 2.2. This comparison however lies closer to the claimed subject-matter than the disclosure of D1. This comparison demonstrates that by maintaining a functionality of about 2 it is possible to optimise the properties of the isocyanate/polyester polyol reaction product.

(b) According to Art. 56 EPC, as applied in T 35/85 of 16 December 1986 (not published in the OJ EPO) an applicant or patent proprietor can discharge the onus of proof by voluntarily submitting comparative tests with newly prepared variants of the closest state of the art making identical the features common with the invention in order to have a variant lying closer to the invention so that the advantageous effect attributable to the distinguishing features of the invention is thereby more clearly demonstrated (T 35/85 Reasons 4).

(c) The comparative examples submitted with the letter of 4 December 2006 correspond to the construction considered in T 35/85 to the extent that CASE materials produced using a polyol according to the invention of the patent in suit (Polyol A - average functionality 2.0) are shown to have improved properties compared to those having a functionality below 2.0, i.e. 1.8 (Polyol B) or above 2.0, i.e. 2.2 (Polyol C). This proves in the Board's view that in the context of the aliphatic polyols claimed, i.e. derived from the specified four components a functionality adjusted to "about" 2 results in a relevant beneficial effect in the resulting CASE material.

4.4.5 The argument of the appellant/opponent that there was no evidence for an effect associated with the restriction of the definition of component (c) which had been effected to provide a distinction over example 27 of D1 (which represented the closest state of the art with which the respondent/patent proprietor would have been obliged to provide a comparison, thus effectively transferring to him the burden of proof) has to be seen in the light of the experimental data referred to in section 4.4.4(c) above), and in view of the considerations which follow:

(a) It is the burden of the party challenging the decision of the first instance - here the appellant/opponent - to prove its case (T 667/94 of 16 October 1997, not published in the OJ EPO, reasons, 3). This would indicate, in the present case that the burden of proof, which in opposition proceedings initially always lies with the opposing party or parties, remains with the appellant/opponent.

(b) It is true in the special circumstances of the present case where the feature restricted compared with D1 (the definition of Component (c)) is not the same as the feature varied in the comparative tests supplied by the respondent/patent proprietor with the letter of 4 December 2006 (the functionality of the resulting polyol) that the Board might have concluded that the failure of either party to provide a comparison with the closest state of the art, Example 27 of D1, left a "residual burden" of proof on the respondent/patent proprietor to fill this gap with further evidence of its own. In this connection, however, it has to be borne in mind that the subject-matter of operative claim 1, both before and after amendment, has been restricted to a polyol composition which is the reaction product of the four components (a), (b), (c) and (d), whereas the general teaching of D1 is that the component (d), corresponding to component (c) of operative claim 1 should not be added as a reactant but only as an additive to the formed product (of (a), (b) and (c)), the functionality of the product of (a), (b) and (c) furthermore not being required to be other than "less than 3" (see section 4.4.2, above). Thus, the distinction of the subject matter of operative claim 1 over example 27 of D1 has to be seen as the replacement, as a reactant, of trimethylol propane by a substance corresponding to post-reaction additive (d) of D1, now as a reactant, with simultaneous maintenance of the overall functionality of the product at "about 2" (see section 4.4.3, above). Consequently the amendment restricting the choice of the reactant component (c) merely emphasised a constellation of subject matter, different from the disclosure of D1, which was present all along.

(c) In the present case, furthermore, the respondent/patent proprietor has already provided evidence of its own with the submission of the experimental report of 4 December 2006 (see section 4.4.4(c) above), which illustrates in a comparison lying closer to the claimed subject-matter than the closest state of the art (Example 27 of D1) and emphasising the distinction with respect to said closest state of the art, that a polyol composition having been prepared by reaction of the four components specified in claim 1 is able to produce a CASE material the combination of relevant properties of which is optimised as the functionality approaches 2, whether from above or below. This already refutes the main contention of the appellant/opponent that the combination claimed is based on an arbitrary selection. Furthermore, since the nature of the comparative data supplied by the respondent/patent proprietor on 4 December 2006 is closer than a comparison with D1 would have been in view of the principles established in T 35/85 (see section 4.4.4(b) above), the Board is obliged, even in the case that the burden of proof would have transferred from the appellant/opponent to the respondent/patent proprietor, to regard this data, in the absence of contrary data of the appellant/opponent, as discharging that burden.

(d) Finally, since the accuracy of the data of 4 December 2006 has not been challenged, the Board is also obliged to recognise this as evidence that the objective technical problem corresponds to that set out in paragraph [0008] of the patent in suit (see section 4.4.1, above) and that this problem has been credibly solved by the claimed subject-matter.

4.4.6 Obviousness

(a) D1 does not disclose either a general requirement for a functionality of about 2, nor does it contain any indication that any advantage would generally be attained by employing polyester polyols having a functionality of about two.

(b) Nor does D1 disclose that the polyester polyols thereof are the reaction product of the four components specified in the operative claims, as explained above. Although all four components are disclosed in D1 the teaching thereof is that those identified as (a), (b) and (d) in the operative claims are to be reacted and the resulting product may optionally be blended with a compound corresponding to that identified as (c) in the operative claims. It is neither explicitly disclosed nor even suggested that this compound might instead be reacted with the other co-reactants.

(c) Finally it is also apparent that the problem which D1 sets out to address is not the same as that underlying the patent in suit, although related thereto. Specifically D1 aims to improve the compatibility of the polyester polyols with blowing agents thus avoiding the need for compatibilisers, in order to produce rigid foams having high rigidity, friability resistance and burn char (see section 4.4.2 above). In contrast thereto the aim of the patent in suit, as explained in section 4.4.1 above is to provide low viscosity polyester polyols giving rise to CASE materials having optimised mechanical properties (see also section 4.4.4, above). Further, as regards the properties of the final products, certain of those, specifically tensile strength and adhesion discussed in the patent in suit (paragraph [0003]) are not addressed in D1.

(d) Hence D1 does not suggest the specific modifications which would be necessary to arrive at the claimed subject-matter for any reason, let alone to achieve an optimisation of CASE materials properties since D1 does not address these properties. Accordingly D1 does not render the subject-matter claimed according to the third auxiliary request obvious.

4.5 Request to consider D2 and D4 At the oral proceedings before the Board the appellant/opponent sought to refer to D2 and D4 in support of its submissions with respect to inventive step (see section IX.(e) above). Neither of these documents had been relied upon in the argumentation presented in the statement of grounds of appeal, although both documents were referred to in the list of documents cited in the procedure (see section V.(a) above). As held by this Board in a different composition (T 561/05 of 5 December 2007, not published in the OJ EPO, reasons 4.1 and 4.2) the requirement of Art. 10(a)2 of the Rules of Procedure of the Boards of Appeal then in force (corresponding to Art. 12(2) of the version which entered into force together with the revised version of the EPC), that the statement of grounds of appeal shall contain a party's complete case and in particular the requirement that this should specify expressly all the facts, arguments and evidence relied upon is not satisfied merely by a general reference to a document, or a general reference to submissions made in the opposition proceedings in the absence of the setting out of any pertinent facts or arguments with respect to the elements thereof on which it is intended to rely. The conclusion is that the attempt to introduce arguments based on the teachings of D2 and D4 at the oral proceedings before the Board, i.e. on the last possible day, constituted - inadmissibly - a change to the case presented in the statement of grounds of appeal. Accordingly the Board did not permit submissions with respect to these documents.

4.6 In view of the foregoing it is concluded that the claims of the third auxiliary request meet the requirements of the EPC.