T 0037/01 18-06-2003

Reasons for the Decision

1. The appeal is admissible.

Main request

2. Article 123(2) EPC

2.1. Claim 1 differs from Claim 1 as originally filed by the incorporation of the feature (i) that the semi-aromatic polyamide used as second polyamide (b) is different from the first polyamide (a), and of the feature (ii) that the first polyamide (a) is crystalline or partially crystalline.

2.2. Although feature (i) has no explicit basis in the application as originally filed, it is however implicit from the expression "first polyamide" and "second polyamide" used for qualifying respectively the polyamide (a) and the polyamide (b) that these polyamide resins must be different. Thus, in the Board's view, the incorporation of the term "different" merely emphasizes this fact and does not provide a technical contribution to the subject-matter of the claimed invention.

2.3. Amendment (ii) finds its support on page 3, lines 15 to 16 of the application as originally filed.

2.4. Claims 2 to 20 correspond to Claims 2 to 20 as originally filed.

2.5. Thus, it follows from the above that Claims 1 to 20 meet the requirements of Article 123(2) EPC.

3. Article 123(3) EPC

3.1. Claims 1 to 20 differ from Claims 1 to 20 as granted only by the fact that the feature (ii) as indicated in paragraph 2.1. above has been incorporated in Claim 1.

3.2. Since the incorporation of this feature amounts to a limitation of the claimed subject-matter in comparison to that of the granted patent, no objection under Article 123(3) EPC arises in respect of Claims 1 to 20.

4. Clarity

4.1. When amendments are made to a patent during an opposition, Article 102(3) EPC requires consideration as to whether the amendments introduce any contravention of any requirement of the Convention, including Article 84 EPC. However, Article 102(3) EPC does not allow objections to be based upon Article 84. EPC, if such objections do not arise out of the amendments made (cf. also T 301/87; OJ EPO 1990, 335).

4.2. In the present case the only amendment made in the course of the opposition was the incorporation of the expression "crystalline or partially crystalline" before the term "first polyamide" in Claim 1 as granted.

4.3. Thus, the question boils down as to whether this expression introduces unclarity in Claim 1.

4.4. The introduction of the term "crystalline" was not disputed by the Parties and the Board sees no objection of lack of clarity arising from the introduction of this term in Claim 1.

4.5. At the oral proceedings the Appellant submitted that the feature "partially crystalline" introduced unclarity since, in its opinion, no clear distinction could be made between an amorphous polyamide and a partially crystalline polyamide. In its view, the relative term "partially" did not define a lower limit of crystallinity, and such a vague term could not be used for distinguishing the claimed subject-matter from document D6, which in particular referred to copolyamides having the same starting components as the first polyamide according to the patent in suit, but being presented as amorphous in D6 (cf. D6, column 5, lines 4 to 17).

4.6. In the Board's view, this argument is not convincing for the following reasons:

4.6.1. The argument of the Appellant is essentially based on document D6, which, however, refers to compositions comprising a semicrystalline polyamide and an amorphous polyamide (cf. D6, column 4, lines 6 to 18).

4.6.2. Thus, the disclosure of D6 itself evidently presupposes, that a clear distinction can be made between a semicrystalline polyamide and an amorphous polyamide.

4.6.3. In that respect, D6 discloses that the term "amorphous polyamide" is well known to those skilled in the art and the characteristic lack of crystallinity in amorphous polyamides can be shown by a conventional method such as differential scanning calorimetry (cf. D6, column 4, lines 19 to 25).

4.6.4. Thus, document D6, on the basis of which the objection of lack of clarity was raised, establishes, on the contrary, that it is clear for the skilled person where and how the borderline between a semicrystalline polyamide and an amorphous polyamide is to be found.

4.6.5. Since the terms "semicrystalline" and "partially crystalline" are indeed synonyms, it follows from the above that no objection of lack of clarity arises from the incorporation of the term "partially crystalline" in Claim 1.

4.7. Thus, the amendment to the claims do not introduce any unclarities. Accordingly the requirements of Article 84 EPC are complied with.

5. Sufficiency of disclosure

5.1. In the Board's view, there can be no doubt that the polyamide (a) used in the examples of the patent in suit is a copolyamide obtained from hexamethylene diamine, 2-methyl pentamethylene diamine, and terephthalic acid, since the nomenclature used in the patent in suit for designating this polyamide (i.e. 50/50% 6T/DT) unambiguously corresponds to the one used in the art for copolyamides. This is also further evident from the fact that a similar nomenclature 55/45% 66/6T has been used for characterizing the product Arlen C2000 of Mitsui Japan which is known as a copolyamide of hexamethylene diamine, adipic acid, and terephthalic acid (page 7, line 31). It thus follows that the skilled person is clearly taught to use a copolyamide as component (a) for carrying out the claimed invention.

5.2. The Appellant has further argued that the patent in suit contains no indication as to how to prepare a component (a) from aromatic dicarboxylic acids other than isophthalic and terephthalic acid so that the skilled person would not know how to prepare such a component (a).

5.3. In that respect it is noted by the Board that the patent in suit contains a very detailed description of a process for making a copolyamide (a) while using isophthalic or terephthalic acids as aromatic dicarboxylic acids (cf. page 3, lines 34 to 49), so that it is credible to the Board that the skilled person, using common technical knowledge, would, without undue burden, know how to adapt this process to other aromatic dicarboxylic acids (analogy process).

5.4. The Appellant has further questioned the feasibility of the preparation of the claimed composition by arguing that transamidation would occur and would prevent that a blend of the two polyamide components be obtained.

5.5. Even if, as admitted by the Respondent, some degree of transamidation could occur, the issue raised by the Appellant is an issue which would normally be decided in the light of relevant experimental evidence, showing that the level of transamidation is such that no blend of the two polyamides can be obtained. No such evidence has, however, been submitted by the Respondent, although the Respondent has the onus of the proof of its allegation (cf. T 182/89, OJ EPO 1991, 391).

5.6. Thus, it has not been shown to the satisfaction of the Board that there is a deficiency in the patent in suit in the sense of Article 100(b) EPC. Consequently, the ground of opposition under Article 100(b) EPC cannot succeed.

6. Novelty

6.1. Documents D4 and D6 have been cited by the Appellant in support of its objection of lack of novelty against Claim 1 of the patent in suit.

6.2. Document D4 has been published on 3 August 1995 i.e. after the filing date of the patent in suit (i.e. 28 April 1994), but D4 claims the priority of the JP patent application 94/006937 of 26 January 1994, i.e. a priority date between the filing dates of the two US patent applications (i.e. 30 April 1993 and 19 April 1994), the priority of which is claimed by the patent in suit. It is thus necessary prior to assessment of novelty in view of D4 to determine (i) whether D4 is entitled to its priority, and, in the affirmative, (ii) to which extent the patent in suit is entitled to the priority date of the first US patent application (D2).

6.2.1. The Respondent has not contested that document D4 is entitled to the priority of the JP 94/006937. It is also evident in view of the comparison between Claims 1 to 6 of the JP-A-07216223 i.e. the Japanese patent corresponding to the Japanese patent application JP94/006937 (cf. D5 pages 1 and 2) and Claims 1 to 6 of D4, that D4 is entitled to the priority of this Japanese patent application.

6.2.2. Priority document D2 relates to compositions comprising a first crystalline or partially crystalline polyamide prepared from terephthalic or mixtures thereof with isophthalic acid, hexamethylene diamine and 2-methyl pentamethylene diamine, and an aliphatic polyamide and a mineral filler (cf. D2, page 3, lines 8 to 34).

6.2.3. While Claim 1 of the patent in suit is directed to compositions in which the first copolyamide is not restricted to those obtained from terephthalic acid or mixtures thereof with isophthalic acid and while it further relates to compositions in which the second polyamide may be a semiaromatic polyamide, it nevertheless enjoys the priority of D2 for the part of the claimed subject-matter also disclosed in D2, i.e. the compositions mentioned in paragraph 6.2.2 above (Article 88(2) EPC).

6.2.4. It thus follows that document D4 belongs to the state of the art according to Article 54(3)(4) for the patent in suit only in respect of the subject-matter not disclosed in D2, i.e. the compositions according to Claim 1 of the patent in suit based on a first polyamide obtained from an aromatic dicarboxylic acid other than terephthalic acid or mixture thereof with isophthalic acid, and the compositions comprising a semi aromatic polyamide as second polyamide (cf. also T 352/97 of 24 October 2000, not published in OJ EPO).

6.2.5. Document D4, however, relates only to polyamide resin compositions comprising (A) 30-90 weight percent, based on components (A) and (B), of a polyamide resin containing (i) 10-99 weight percent, based on components (i) and (ii) of an aromatic polyamide containing a carboxylic acid component derived from terephthalic acid or a mixture of terephthalic and isophthalic acid in which the isophthalic acid constitutes 40. mole percent or less of the mixture, and an aliphatic diamine component derived from a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine; and (ii) 1-90 weight percent, based on components (i) and (ii), of an aliphatic polyamide resin and (B) 10-70 weight percent, based on components (A) and (B), of an inorganic filler (cf. D4, Claim 1). Consequently, D4 cannot destroy the novelty of Claim 1 of the patent in suit.

6.3. Document D6 belongs to the state of the art according to Article 54(2) EPC. It discloses compositions consisting essentially of about 50 to about 95 percent by weight of an ethylene vinyl alcohol copolymer having a copolymerized ethylene content of about 20 to about 60 mole percent and a degree of saponification of at least about 90 %, and about 5 to about 50 percent by weight of a polyamide blend consisting essentially of about 30 to about 90 percent by weight of at least one amorphous polyamide characterized by the lack of an endothermic crystalline melting peak as measured by differential scanning calorimetry and further characterized by a glass transition temperature of up to about 160°C, and about 10. to about 70 percent by weight of at least one semicrystalline polyamide which is miscible with the ethylene vinyl alcohol copolymer. The amorphous polyamide may be a copolymer of hexamethylene diamine and 2-methylpentamethylene diamine with iso- or terephthalic acids, or mixtures of these acids, and the semicrystalline polymer is an aliphatic polyamide selected from polyamides prepared from lactams or amino acids, polyamides obtained by condensation of aliphatic diacid with aliphatic diamines or copolymers thereof. D6 further mentions that fillers may be added to the compositions (cf. D6, Claims 1, 4; column 5, lines 46 to 60; column 7, lines 56 to 59).

6.4. Firstly, the copolyamide of hexamethylene diamine and 2-methylpentamethylene diamine with iso- or terephthalic acids used in the composition of D6 is amorphous instead of being crystalline or partially crystalline as required by Claim 1 of the patent in suit, and, secondly, D6 is totally silent on the nature of the filler used (i.e. mineral or organic). Thus, it is evident that D6 does not disclose a composition according to Claim 1 of the patent in suit.

6.5. The further argument of the Appellant that the fact that D6 teaches to not use crystalline polyamides implicitly informed the skilled person that the possibility existed that component (a) could be crystalline or at least partially crystalline is not convincing either. A document can only be novelty destroying provided it discloses directly and unambiguously the claimed invention. This unambiguous disclosure does not encompass such hypothetical embodiments which are contrary to the teaching of this prior art document, and which, consequently, the skilled person would have no technical motive to consider (cf. decision T 943/93; of 30 August 1994, not published in OJ EPO).

6.6. Consequently, D6 does not destroy the novelty of the subject-matter of Claim 1 of the patent in suit.

6.7. It thus follows from the above that the subject of Claim 1 is novel over the cited prior art. The same conclusion applies to the subject matter of dependent Claims 2 to 17 and to the subject matter of Claims 18, and 19 to 20 which relate to a fiber or a moulded product made from a composition according to Claim 1, respectively (Article 54 EPC).

7. The patent in suit, the technical problem

7.1. The patent in suit is concerned with semiaromatic polyamide compositions comprising mineral filler.

7.2. Such compositions are known from document D8 which the Board, in common with the Parties and the Opposition Division, regards as the closest state of the art.

7.3. Document D8 relates to compositions comprising partially crystalline copolyamides formed from an aromatic carboxylic acid and a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine. The aromatic carboxylic acid is terephthalic acid or a mixture of terephthalic acid and isophthalic acid. The copolyamides have a melting point of greater than 280°C and less than 330°C, especially greater than 300°C. The copolyamides may be blended with stabilizers, flame retardants, smoke depressants, plasticizers, conductive and/or anti-static agents, lubricants and mould release agents, nucleating agents, dyes and pigments, fillers including glass fibres, minerals, toughening and other modifying agents, and other additives that may be used in polyamide compositions. A wide range of fillers may be used e.g. in amounts of 0.5-200 parts of filler per 100 parts of copolyamide. Examples of such fillers included silica, metasilicates, alumina, talc, diatomaceous earth, clay, kaolin, quartz, glass, mica, titanium dioxide, molybdenum disulphide, gypsum, iron oxide, zinc oxide, fibres (e.g. glass, ceramic fibres). The compositions may be used in the manufacture of products using melt processing techniques, especially products intended for use at temperatures that are higher than those typically used with other polyamides e.g. parts requiring resistance to temperatures of 260°C or above. Alternatively, they may be spun into fibres (cf. D8, Claims 1, 5, 6, 19, 20; page 6, lines 5 to 26).

7.4. According to the patent in suit semiaromatic, semi- crystalline polyamide compositions, while exhibiting a high temperature resistance (high HDT), tend to crystallize very slowly, require high mould temperatures and are often unsuitable for applications requiring a glossy surface (cf page 1, line 17 to page 2, line 5).

7.5. Starting from D8, the technical problem may thus be seen in the provision of semiaromatic polyamide compositions having improved mouldability and crystallization properties (reflected by a low Tcc), i.e. allowing the use of lower mould temperature, while exhibiting high temperature resistance (reflected by a high Tg and a high HDT)) and good surface properties (glossy surface) (cf. page 2, line 6 to 13; page 3, lines 1 to 2).

7.6. The solution proposed according to Claim 1 of the patent in suit is to add an aliphatic polyamide resin or a different semiaromatic polyamide to the composition comprising the crystalline or partially crystalline semiaromatic polyamide.

7.7. While the compositions of Examples 1 to 15, and 17 of the patent in suit exhibit a low Tcc, high Tg and HDT, and a glossy surface, it is true, as submitted by the Appellant, that the composition of Example 16 results in a matte surface appearance. It is, however, noted by the Board that the composition of Example 17, which differs from that of Example 16. only by the incorporation of glass fibres in the composition exhibits a glossy surface, although glass fibres are generally known to degrade the surface appearance. Thus, in the Board's view, this occasional lack of success cannot impair the credibility of the solution proposed by the patent in suit. It thus follows that the Board is satisfied that the technical problem is effectively solved by the claimed measures.

8. Inventive step

8.1. It remains to be decided whether the solution of the technical problem was obvious to a person skilled in the art having regard to the relevant prior art.

8.2. Although D8 discloses a long list of additives which might be used in the compositions (cf. point 7.3 above), it is totally silent on the incorporation of further polyamides such as aliphatic polyamides or semiaromatic polyamides. Furthermore, it teaches to add nucleating agent in order to improve the crystallization rate of the compositions (cf. page 15, lines 20 to 22). Thus, document D8 itself cannot suggest the solution of the technical problem.

8.3. Document D7 relates to compositions comprising a polyamide obtained from terephthalic acid, hexamethylene diamine, 2- methyl pentamethylene diamine and optionally 2-ethyl pentamethylene diamine, and a filler such as talc, mica, glass fibres or asbestos fibres. While the aim of D7 presents some similarity to that of the patent in suit i.e. in providing compositions having a high HDT of at least 240°C and high crystallization rate allowing the use of low mould temperatures, D7 firstly solves this problem by using a specific amount of hexamethylene diamine i.e. from 40 to 90% by mole in the diamine component of the single polyamide and, secondly, gives no indication of the surface appearance of the moulded parts obtained (cf. D7; page 2, line 29 to page 4, line 28). Thus, D7 cannot lead to the solution of the technical problem.

8.4. Documents D9, D11 and the late filed document D12 which relate to compositions comprising a semiaromatic polyamide and a mineral filler, all teach to modify the starting components of the semi aromatic polyamide, i.e. the dicarboxylic acid component and/or the diamine component in order to improve the mouldability of such compositions while maintaining good thermomechanical properties (cf. D9, column 2, line 48 to column 3, line 61; cf. D11, Claim 1; column 1, lines 29 to 64; column 5, lines 7 to 37; cf. D12, page 3, line 31 to page 4, line 14).

8.4.1. The reference to the possibility of adding other polyamides, such as nylon 12, nylon 11, nylon 69, nylon 610 or nylon 66 which are aliphatic polyamides (cf. D11, column 5, lines 43 to 60) is mentioned in passing and in particular is not associated with any suggestion of what the effect of such addition might be, let alone that it would contribute to the solution of the technical problem.

8.4.2. Hence, neither of these documents would offer to the skilled person a hint to the solution of the technical problem.

8.5. The information contained in documents D10 and D6 is even less relevant, since D10 refers only to compositions based on amorphous polyamides, and since document D6 aims to provide thermoformable ethylene vinyl acetate compositions by adding therein a polyamide blend.

8.6. In other words, it follows from the above that the solution of the technical problem does not arise in an obvious way from the state of the art.

8.7. Consequently, the subject-matter of Claim 1, and by the same token that of dependent Claims 2 to 17 involves an inventive step. Furthermore, the subject-matter of Claims 18, and 19 to 20, which are respectively directed to a fibre and a moulded product obtained from a composition according to Claim 1 also involves an inventive step (Article 56 EPC).