T 0427/14 18-10-2017

1. Main request - claim 1 - inventive step

1.1 Claim 1 is directed to a method of preparing a blocked isocyanate solution by one of two reaction routes:

- reaction of a polymeric isocyanato compound and propylene glycol or

- reaction of a polymeric primary or secondary amine and propyl carbonate

to provide a beta-hydroxypropyl urethane polymer.

The resulting product is combined with propylene glycol monomethyl ether to provide a "pourable" solution.

1.2 Interpretation of the claim

The claim is unambiguous in that the product is a urethane polymer wherein the urethane groups are blocked with beta-hydroxypropyl groups.

The first of the indicated methods, i.e. reaction of a polymeric isocyanato compound and propylene glycol, is uncontroversial, since this would clearly lead to a polymeric product. Indeed this is demonstrated by the examples of the patent in suit.

Regarding the second embodiment there are two aspects which are problematic.

The term "propyl carbonate" whilst denoting a known compound is manifestly erroneous in the context of the patent since reaction with this compound would not yield the stated product. The question was discussed in the (written) proceedings whether the skilled person would realise that the correct term was "propylene carbonate", as mentioned in paragraph [0017] of the patent, and furthermore whether this could be corrected. The Board is satisfied that the skilled reader of the patent would make this notional correction when reading claim 1 of the main request, and this understanding will be employed in the following analysis of inventive step. As this reading is in favour of the appellant and even with this notional correction the conclusion is reached that the claim lacks an inventive step, no deeper analysis is required on this issue.

With regard to the term "polymeric primary or secondary amine" this term is clear to the extent that it denotes a polymeric compound, i.e. one with a plurality of repeating units (of some kind) which bears primary or secondary amine functionality.

The fact that the corresponding part of the description - also paragraph [0017] - appears to define as "polymeric" compounds such as ethylene diamine or diethylenetriamine, which compounds are not in fact polymeric but are polyamines, constitutes an unclarity within the meaning of Article 84 EPC, since there is an inconsistency between the description and the claims. This matter however cannot be addressed in the scope of the present opposition appeal proceedings since the defect existed in the granted patent (following G 3/14). On the other hand, this inconsistency cannot justify a reading of the undoubtedly clear term "polyamine" in claim 1 which is contrary to the usual understanding of the skilled person.

1.3 Closest prior art

According to the decision under appeal the closest prior art was represented by D5 and in particular example 2 thereof. Both parties also relied on this document in their submissions on inventive step. The Board sees not reason to take a different approach from that of the parties.

D5 relates to a process for curing an active hydrogen-containing material employing a curing agent which is the product of a polyfunctional amine and an organic carbonate (claim 1; page 2, lines 12-21). Example 2 of D5 relates in the first part to the preparation of a curing agent by reaction of 2.68 mols m-xylylene diamine with 5.4 moles of propylene carbonate. Following the reaction ethylene glycol monobutyl ether is added to the product to provide a solution with 73.9 wt% solids. It is reported that in the final product only a trace amount of propylene carbonate was detected whereas an amine content of 0.335 milliequivalents was measured.

As a result of the stoichiometry and confirmed by the analytical reports the resulting product will be the m-xylylene diamine wherein each amine is substituted with one propylene carbonate unit, i.e. a m-xylylene diamine substituted with two beta-hydroxypropyl urethane units.

1.4 Distinguishing feature(s)

Claim 1 specifies that the product is the result either of reaction between a polymeric isocyanate compound and propylene glycol or of reaction between a polymeric primary or secondary amine and propylene carbonate and that the product is a beta-hydroxypropyl urethane polymer.

The amine employed in the example of D5 - m-xylylene diamine - is a monomeric compound. This is not a matter of dispute.

The respondent considered that the resulting product, as a consequence of having two beta-hydroxypropylene urethane groupings, each of which could be considered a mer unit fell within the terms of "polymer".

The Board disagrees. A polymer is by definition a molecule built up of repeating units. A difunctionalised diamine as in D5 does not meet this definition since there is only a single diamine unit present and no polymerisation reaction has taken place - this being precluded by the stoichiometry employed. Consequently no repeating mer units, the prerequisite for presence of a polymer, can be identified in the structure of the product of D2, example 5.

Therefore as a first distinguishing feature is that the product of D5, example 2 is not polymeric.

A second distinguishing feature is provided by the fact that a different solvent to that specified in the claims is present (ethylene glycol monobutyl ether instead of propylene glycol monomethyl ether).

1.5 Technical effects and objective problem to be solved

The evidence of the patent in suit relates to polymeric materials, obtained by reaction of a urethane polymer with propylene glycol. The structure of the resulting compound will be the same as that which could be obtained by the polymeric amine/propylene carbonate route. Consequently, potential effects arising from differences in by-products notwithstanding, the examples are relevant for both routes defined in claim 1.

There are however no data relating to the teaching of D5, i.e. monomeric difunctional compounds.

Regarding the solvent, the patent does include in table 1 examples showing different solvents, however the solvent of D5 is not here exemplified.

Accordingly there is no evidence which is suitable to demonstrate a technical effect arising from the distinguishing features of the claimed subject-matter - either singly or in combination - with respect to the teaching of D5.

In view of the available evidence the only technical problem that can be formulated is the provision of further methods for preparing solutions of blocked isocyanates.

1.6 Obviousness

D5 lists on page 3 starting at line 4 possible compounds which can be employed as the polyfunctional amine. Among these compounds are polymeric amines, namely polyoxypropylene polyamines identified by the commercial designation "Jeffamine 405" and an adduct of a polyepoxide and polyalkylene polyamine (page 3, line 13-19).

Consequently D5 itself proposes that polymeric amines can be employed in the preparation of the target curing agent, making this feature of operative claim 1 obvious when seeking further methods according to the indicated problem.

Regarding the solvent, D5 states on page 5, lines 9-11: "Examples of useful solvents are toluene, xylene, acetone, ethylene glycol monoethyl ether and the like".

This disclosure teaches generally solvents which are analogues of that as defined in operative claim 1, making it obvious to select also further analogues, including that now defined in the claim. Furthermore in the second part of example 2 of D5 in which a curable composition is prepared "Dowanol PM" is employed which is a commercial name for propylene glycol monomethyl ether (see table on pages 17 and 18), the solvent specified in operative claim 1.

Consequently D5 also renders the selection of a different - analogous - solvent to that specifically employed in example 2 thereof obvious when looking for further methods according to the stated problem and even includes - indirectly - a suggestion as to which solvent could be employed.

The conclusion is therefore that the subject-matter of operative claim 1 represents an obvious solution to the objective problem with respect to D5 with the consequence that an inventive step cannot be recognised.

1.7 The main request does not therefore meet the requirements of Article 56 EPC.

2. Auxiliary requests

2.1 Auxiliary requests 1, 3 and 5

In claim 1 of these requests, the term "propyl carbonate" has been replaced by "propylene carbonate".

In view of the reading of claim 1 of the main request mentioned above (point 1.2) in which propyl carbonate was already understood as meaning propylene carbonate, the same analysis of inventive step applies as outlined for the main request with the consequence that claim 1 of these requests lacks an inventive step.

2.2 Auxiliary requests 2 and 4

Claim 1 of these requests is identical to that of the main request meaning that the same conclusions apply.

2.3 Auxiliary requests 6 to 11

Claim 1 of these requests differs from claim 1 of the main request in that the solids content of the solution is defined as being more than 50% by weight. In addition in auxiliary requests 7, 9 and 11 the term "propylene carbonate" was introduced.

These amendments do not introduce any additional distinguishing feature with respect to the closest prior art because Example 2 of D5 reports a solids content of 73.9 %.

As a consequence the same conclusions in respect of inventive step apply as for the main request.

2.4 Auxiliary requests 12 and 13 - admittance.

These requests were filed in the Appellant's second letter of the appeal proceedings, namely almost two years after the rejoinder of the respondent to the statement of grounds of appeal.

Claim 7 of these requests differs from claim 7 of the patent as granted in that it is directed to the use of the solution of claim 4 for the preparation of a waterborne coating composition rather than to the waterborne coating composition itself (see section X.(b), above).

A claim of this category had never been in the proceedings prior to said submission of the appellant.

In the proceedings before the opposition division claim 7 of the patent as granted was held to contravene the requirements of Article 56 EPC (section 3.1.1.3 of the reasons of the decision). During the course of the oral proceedings before the opposition division the patent proprietor filed two auxiliary requests (6 and 7) in which the claim corresponding to claim 7 of the main request had been amended into a claims of the "method" category. These claims were considered to contravene the requirements of Article 123(2) and (3) EPC (minutes of the oral proceedings sections 6.2 and 6.3, decision sections 6.2 and 6.3).

Consequently it was apparent from the decision that the opposition division considered that there was a problem with claim 7 of the patent as granted and that the approaches taken by the patent proprietor to address this were unsuccessful.

It would have been incumbent on the patent proprietor, if it was wished to pursue this approach, to provide appropriate requests at the earliest possible stage, i.e. with the statement of grounds of appeal and not only later.

In addition claim 1 of auxiliary request 12 is identical to claim 1 of the main request and therefore does not address the critical issues of the previous requests and claim 1 of auxiliary request 13 contains inter alia a definition of the term "pourable" which does not correspond to the definition in the description and potentially raises new issues under Articles 123(2) and 84 EPC.

The presentation of these claims a long time after the commencement of the appeal proceedings, introducing a new category of claims never before present in either the first or second instance proceedings while introducing amendments which potentially gave rise to further issues (auxiliary request 13) represented a change of case of the appellant. It is recalled that according to Article 12(2) RPBA it is required that the statement of grounds of appeal contain the complete case and that according to Article 13(1) RPBA it is a matter for discretion of the Board whether to admit amendments to a party's case.

There were no developments solely within the scope of the appeal proceedings which can be considered to have given rise to the need to file said requests. Indeed, as indicated above, the problems were already apparent during the opposition proceedings. Moreover, the requests either do not address the outstanding issues or raise further potential problems.

Accordingly the Board in exercise of the discretion allowed pursuant to Article 13(1) RPBA does not admit auxiliary requests 12 and 13 to the proceedings.

3. Auxiliary request 14 - admittance

This request was filed at the end of the oral proceedings before the Board, i.e. at the very last moment of the whole procedure.

As explained in section X.(c), above claim 1 of this request differs from claim 1 of the main request by:

- eliminating the embodiment "polymeric primary or secondary amine and propyl carbonate" and

- defining the nature of the isocyanato compound.

This form of claim had never previously been presented in either the opposition or the appeal proceedings.

The Board in its communication had indicated that there appeared to be a problem with the definition of the polymeric primary or secondary amine embodiment due to the disclosure in the description according to which polyamines were considered to be polymeric amines. Consequently at the latest at this stage of the proceedings, well in advance of the oral proceedings, the appellant was made aware that there might be a difficulty with this aspect of the subject-matter claimed and had the opportunity to take steps to address this, e.g. by filing appropriate amendments.

Accordingly there was no justification, arising solely from developments in the course of the oral proceedings before the Board which can be considered - for the first time - to indicate the existence of some potential problem with the "polymeric amine" embodiment of claim 1.

Furthermore the representative of the respondent indicated that in order to deal with this - unforeseeable - development in the proceedings it would be necessary to contact the client to obtain instructions.

The Board is satisfied that the position of the respondent is appropriate and reasonable. At no point in the written proceedings had there been any indication from the appellant that deletion of the polymeric amine/propylene carbonate embodiment of claim 1 was being considered, meaning that neither the Board nor the other party had any reason to expect or to make provision fur such a development.

To deal with this newly filed request would have necessitated adjourning the oral proceedings to a later date. This however would be contrary to the stipulations of Article 13(3) RPBA.

For these reasons auxiliary request 14 is not admitted to the proceedings.

4. Request for reimbursement of the appeal fee

The conclusion to be drawn from the foregoing is that the appeal of the patent proprietor is not allowable. Consequently the request for reimbursement of the appeal fee must be refused (Rule 103(a) EPC).