T 1006/04 09-01-2009

Reasons for the Decision

1. The appeal is admissible

Novelty over document (1)

2. The patent had been opposed under Article 100(a) EPC solely on the ground that the claims lacked an inventive step in view in particular of document (1). In the appeal proceedings, the Appellants have raised an objection for lack of novelty in view of that document. This objection had been raised before the opposition division after expiry of the time limit laid down in Article 99(1) EPC. Regardless of whether the ground of lack of novelty based upon Articles 52(1) and 54 EPC should be considered to have been admitted into the proceedings by the opposition division or should be considered as a fresh ground for opposition which accordingly could not be introduced into the appeal proceedings without the agreement of the patentee (see G 1/95 and G 7/95 (OJ 1996, 615 and 626)), the allegation that the claims lack novelty in view of the closest prior art document, i.e. in the present case document (1) as shown hereinafter, will be considered in the context of deciding upon the ground of lack of inventive step (see G 7/95 (OJ 1996, 626)).

Inventive step

Closest prior art

3. Document (1) which is described in paragraphs [0004] and [0005] of the patent in suit as starting point for the present invention is considered by both parties to represent the closest prior art and starting point for the assessment of inventive step for the claimed ink compositions. Like the patent in suit, it relates to heatset intaglio printing inks suitable for printing of currency. The inks employed in document (1) and those claimed in the patent under dispute contain the same components a) to d). The parties agreed that if the claimed ink compositions are distinguished from those described in document (1), then solely by the nature of the curing agent e). Thus, the Board too is satisfied that document (1) represents the closest prior art.

Novelty over the closest prior art

4. The curing agent component of document (1) is defined in claim 1 to be an amine curing agent, preferably a diamine according to column 4, line 10. Preferred compounds are according to column 4, lines 11 to 14 and claim 12, selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, dimethylaminopropylamine and mixtures thereof. The examples of document (1) exclusively use the diethylenetriamine as curing agent. Hence, contrary to the appellants' opinion, the curing agent defined in present claim 1 cannot be seen as a selection of the curing agents employed in document (1), because the disclosure of document (1) does not leave any room for interpretation by a skilled person that the amine curing agent of document (1) could encompass an adduct of an amine. Hence, the Appellants' line of argumentation which starts from the premise that the claimed compositions would constitute a selection within those disclosed in document (1) cannot succeed. The Board is furthermore satisfied that the features defining the amine-adduct curing agents of present claim 1, among others the reaction product of an epoxy resin with an amine comprising the compound of the general formula R1R2N-X-NH2, whereby said reaction product is further reacted with phenolic resins and polyhydric phenol compounds are not disclosed in document (1). Thus, the appellants' objection that the claimed subject-matter lacks novelty over the closest prior art must be rejected.

Problem solved

5. In view of this state of the art both parties agreed, making reference to the examples of the patent in suit, that the claimed ink compositions cured at lower temperature, thereby minimizing the yellowing and concurrently maximizing the flexibility of the paper substrate, while at the same time meeting the following properties (a) to (g):

(a) correct rheological properties in respect to transfer of the ink to the printing cylinder and transfer therefrom to the substrate;

(b) ability of the excess ink to be easily and quantitatively removed from the non-image areas of the die surface by the wiping cylinder (wipeability);

(c) ease of cleaning the wiping cylinder by means of a dilute aqueous caustic soda solution containing about 1% of NaOH and 0.5% sulfonated castor oil or other surfactants;

(d) stability of the ink on the printing rollers; i.e. control of the evaporation of volatile materials during the printing process;

(e) film-forming characteristics allowing handling of the webs carrying printed films of up to 200 mµ thickness immediately after printing;

(f) proper drying properties when printing at speeds of up to 200 m/min with engravings of up to 200 mµ thickness;

(g) outstanding chemical and mechanical resistance of the printed document pursuant to specifications established by INTERPOL at the 5th International Conference on Currency and Counterfeiting in 1969 and by the U.S. Bureau of Engraving and Printing in BEP 88-214 (TN) §M5.

6. According to paragraph [0023] of the patent under dispute, the inks dry rapidly. Typically the imprinted substrate will be cured in ovens of 5-6 meters in length at temperatures of 80 to 180ºC and a residence time of 0.1 to 2 seconds. Thus, a second colour may be printed almost instantaneously upon a previously-printed colour.

7. Hence, the proper drying properties (f) as defined in paragraph [0006] of the patent in suit mean that the claimed inks dry rapidly, such as to allow the printing of a second colour almost instantaneously upon a previously-printed colour. This statement is supported by the process exemplified in paragraphs [0030] and [0031] of the patent under dispute. The Board cannot find any support in the patent in suit that the time required for a complete cure of the claimed inks should take place within 0.1 to 2 seconds, as this curing time is not indicated to be met by all claimed compositions, but is only indicated as typical in the context of specific process conditions.

8. The Appellants cited documents (2), (3), (7) and (8) as evidence for the contention that some curing agents falling within the definition of compound (e) would not allow the claimed inks to dry rapidly.

8.1 Document (2) relates to the curing agent used in the examples of the patent in suit, namely Ancamine 2014FG and describes its use for metal-to-metal, plastic-to-plastic bonding and solvent free laminating applications. On the basis of the indication in document (2) that Ancamine 2014AS, i.e. a curing agent of type (e) according to the patent in suit, exhibits a lower reactivity than Ancamine 2014FG, the Appellants alleged that inks according to the patent in suit which contain Ancamine 2014AS would not dry rapidly and thus would not solve the problem formulated above. According to paragraph [0021] of the patent in suit, which is confirmed by document (2) itself, Ancamine 2014AS and Ancamine 2014FG differ from one another only in their particle size and not in their chemical nature. The mere indication in document (2) that Ancamine 2014AS is described, in the context of epoxy compositions for metal-to-metal, plastic-to-plastic bonding and solvent free laminating applications, to exhibit a lower reactivity than Ancamine 2014FG cannot serve as evidence that Ancamine 2014AS when used in a different context and with a different type of resin composition, would not provide a curing fast enough to allow the printing of a second colour almost instantaneously upon a previously-printed colour. The passage relied on by the appellants is inconclusive, as these less reactive curing agents, even if they might be expected to need a longer curing time, may still give a curing time which is fast enough for the purpose of the present invention, namely allowing printing of a second colour almost instantaneously upon a previously-printed colour. Thus, it cannot be deduced from document (2) that the problem mentioned above is not solved for compositions comprising Ancamine 2014AS as curing agent.

8.2 Document (7), which relates to one-part epoxy compositions systems employed in coating operations, was cited in order to show that Ancamine 2014 AS would provide a latency period of up to several hours at temperature comprised between 120º and 270ºF (i.e. 49 and 132ºC) (column 1, lines 59-64 and column 3, line 56). The latency period of the compositions taught in document (7) is according to column 3, line 40 and claim 1 of document (7) about 30 minutes at those temperatures. The Appellants' argumentation, however, ignores the fact that the latency period addressed in document (7) does not result from the use of ANCAMINE 2014AS, but rather from dicyandiamine or dicyandiamide-aromatic amine adducts used as latent curing agent, as shown in claim 1 and column 3, lines 26-48. ANCAMINE 2014AS is merely described in document (7) as an agent which for some unspecified applications might provide an adequate latency and at the same time be able to accelerate the curing process (column 3, lines 49-58). The mere indication that for some applications, ANCAMINE 2014AS might provide the required latency, which however is not further specified, is insufficient to allow any conclusions as to whether under the specific conditions and compositions used in the patent in suit, ANCAMINE 2014AS would or would not allow the printing of a second colour almost instantaneously upon a previously-printed colour. Therefore, reliance on document (7) cannot be considered as adequate evidence that the problem addressed above is not solved, when Ancamine 2014AS is employed as curing agent.

8.3 As acknowledged in paragraph [0021] of the patent in suit document (3) describes the preparation of compounds (e) defined in present claim 1. This document does not relate to printing inks, but to adhesives for structural materials (column 1, lines 12-16, lines 18-20 and lines 51-59), in line with the measurements of the tensile strength on the exemplified cured products (see Tables 1 to 9). The nature of the resins cured in the examples of document (3) and the type of applications envisaged, are however so different from those concerned in the patent in suit, that it is impossible, solely based on the knowledge of the curing time employed in document (3), to draw any conclusions concerning the curing time that would be required for the presently claimed compositions in printing ink applications.

8.4 Document (8) concerns intaglio printing inks of types other than the type employed in the patent in suit. It does not concern a printing ink containing a resin a) as defined in present claim 1, nor does it disclose the use of the curing agents of type e). Document (8) does not provide, therefore, any indication on the curing time typically obtained with the presently claimed compositions.

8.5 Hence, none of the documents cited by the Appellants provides any evidence that the curing agents falling within the definition of compound (e) would not allow the claimed inks to dry rapidly enough to allow the printing of a second colour almost instantaneously upon a previously-printed colour.

9. In view of the processes exemplified in the patent in suit (see Test Results in paragraphs [0030] to [0032] and Table I), it has been rendered credible that the claimed ink compositions cured at lower temperature, thereby minimizing the yellowing and concurrently maximizing the flexibility of the paper substrate, while at the same time meeting the above listed properties (a) to (g), in particular a drying time allowing the printing of a second colour almost instantaneously upon a previously-printed colour. Therefore, the burden of proof for the allegation that the claimed ink compositions would not exhibit a drying time which allows the printing of a second colour almost instantaneously upon a previously-printed colour rests upon the Appellants. It is noted in this context that the Appellants, who had complained that the opposition division had not given them the opportunity to provide the necessary experimental evidence in support of their argument, did not avail themselves of the opportunity to present in the appeal proceedings experimental evidence for their contention. In the absence of such experimental evidence, the Board therefore considers the Appellants' allegation, that the claimed compositions would not allow for some curing agent (e) a drying time which allows the printing of a second colour almost instantaneously upon a previously-printed colour, as mere speculation, which therefore is disregarded. Summing up, the Board is satisfied that the solution provided by the patent under dispute successfully solves the problem underlying the invention as defined in point 5 above.

Obviousness

10. It remains to be decided whether or not the skilled person starting from document (1) and wishing to solve the above defined problem would have been guided by the available prior art to the claimed solution, namely the use of curing agent (e) while keeping components (a) to (d) identical.

10.1 Contrary to the Appellants' opinion, the disclosure of document (1) does not leave any room for interpretation by a skilled person that the amine curing agent of document (1) could encompass an adduct of an amine (see point 4. above). Hence, the closest prior art itself contains no pointer which would lead the skilled person to the claimed solution.

10.2 The Appellants also argued that it would have been obvious to follow the teaching of documents (2), (3) and (7), which showed that the curing agent (e) defined in the present claims cured at lower temperature. The question to be answered is however not whether documents (2), (3) and (7) teach that curing agents of type (e) provide lower curing temperatures, but whether they suggest that this type of curing agent would allow to meet properties (a) to (g) as defined in point 5 above. Documents (2), (3) and (7) do not relate to intaglio printing inks, but to different applications where other expectations concerning the properties of the epoxy resins exist. These documents are silent as to the properties sought to be obtained in the patent under dispute. Furthermore, the curing agents disclosed in documents (2), (3) or (7), as they are reaction products of amines with an epoxy resin and at least one compound consisting of phenolic resins and polyhydric phenol compounds, are structurally not closely related to those used in document (1). Moreover, the properties of the inks of document (1) other than the curing time also depend on the nature of the curing agent utilized, which in the patent under dispute can be contained in an amount of 0.1 to 5 wt% compared to the 10 to 50 wt% of the resin. The mere information that the curing agent (e) may be reactive at lower temperature, which at most might lead the skilled person to consider this curing agent as a potential candidate among other curing agents, also reactive at lower temperatures, for solving a part of the addressed problem, namely avoiding yellowing of the paper, does not make it obvious, that the curing time required would be sufficiently low to avoid yellowing and that at the same time properties (a) to (g) could be obtained, as no relationship between the curing temperature and properties (a) to (g) has been demonstrated to exist. Thus, documents (2), (3) and (7) do not lead to the claimed solution in an obvious manner.

10.3 The other documents cited by the Appellants do no disclose the curing agent used in the present invention and therefore cannot lead to the claimed composition.

10.4 Therefore, there is no case made out that the skilled person in view of the prior teaching available would have arrived at the subject-matter of present claim 1 in an obvious manner.

11. Consequently, the subject-matter of present claim 1 and by the same token that of dependent claims 2 to 10 meets the requirements of Article 56 EPC.

Procedural matters

12. In accordance with Article 1(5) of the Decision of the Administrative Council of 28 June 2001 on the transitional provisions under Article 7 of the Act revising the European Patent Convention of 29 November 2000 ("Revision Act"), Rule 67 EPC 1973, first sentence remains applicable to considering the request for re-imbursement of the appeal fee in this case, since the time limit for making such request had expired before the Revision Act entered into force.

13. Rule 67 EPC 1973, first sentence, provides for the refund of the appeal fee where the Board of Appeal deems an appeal to be allowable and such a reimbursement is equitable by reason of a substantial procedural violation. In the present case the Board cannot find any procedural violation in the conduct of procedure by the opposition division. There is however no need to provide any details on this matter, as the appeal of the patent proprietor has not been allowed, and therefore reimbursement of the appeal fee cannot be ordered for this reason alone.