T 0020/94 (Amorphous TPM/ENICHEM) 04-11-1998

Reasons for the Decision

1. The appeal is admissible.

2. Parties to the appeal

The Respondent 2's declaration to withdraw his opposition is to be understood as withdrawal from the appeal proceedings. Thus, he ceases to be a party to appeal proceedings as far as the substantive issues are concerned (see decision T 789/89, OJ EPO 1994, 482, points 2.3 and 2.6. of the reasons). The Respondent 3 declared at the start of the appeal proceedings that he would not proceed with the appeal procedure. The Board interprets this declaration as a request to cease to be a party to the proceedings. The Board's conclusion, after having been communicated to him, was not contested by the Respondent 3.

3. Late-filed evidence (Article 114(2) EPC)

3.1. Documents (13), (13a) and (14) are new evidence submitted with Respondent 1's letter on 1 August 1994 for the first time. The Appellant has objected to their introduction into the appeal proceedings since they were not prepublished.

The document (13) forms part of the December issue 1986 of a scientific journal and the abstract (13a) thereof was published in 1987. The priority date of all the claims of the patent in suit being 25 July 1986, both documents are postpublished and unable to be relevant in the assessment either of novelty or of inventive step. Thus, these late filed documents are not admitted into the proceedings (Article 114(2) EPC). Document (14), which identifies the structure of the commercial product used in document (13), could only be admitted if the latter were admitted; therefore document (14) is not admitted into the proceedings.

3.2. The indication of the purity of the commercially available products Irganox and Sunnox is a new fact and the HPLC spectra thereof are new evidence submitted for the first time on 28 September 1998 by the Appellant during appeal proceedings. No reason has been given for this late filing, nor can the Board see any such reasons. These facts and evidence are intended to support novelty of the process claims of the patent in suit; the claims, however, are already novel for other reasons as set out below (cf. point 6. below). Therefore, these facts and evidence lack relevance for the decision to be taken and are not admitted into the proceedings (Article 114(2) EPC).

3.3. The Appellant's experimental report, repeating some experiments of document (12), is new evidence submitted for the first time on 28 September 1998 during appeal proceedings. No reason has been given for this late filing. This evidence is intended to support inventive step of the claimed process in view of that document. However, the teaching of document (12) is not relevant in the assessment of inventive step (cf. point 7 below). Therefore, the evidence based thereon lacks relevance for the decison to be taken either, and is not admitted into the proceedings (Article 114(2) EPC).

Main Request

4. Amendments (Article 123(3) EPC)

4.1. The patent in suit in the form as granted comprised exclusively process claims for preparing amorphous tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane. The patent in suit in the form as amended now comprises a product claim relating to this amorphous product per se (see point V. A above).

4.2. There are basically two different types of claim, namely a claim to a physical entity, e.g. a product, and a claim to a physical activity, e.g. a process for preparing a product (see decisions G 2/88, OJ EPO 1990, 93, point 2.2. of the reasons; T 150/82, OJ EPO 1984, 309, point 7 of the reasons). These two basic types of claim are referred to as the two possible categories of claim. Therefore, the proposed amendment of the patent in suit as granted according to the main request consists in a change of the category of the claims, i.e. a switch from the category of a physical activity to the category of a physical entity.

4.3. Article 123(3) EPC requires that the claims of a patent may not be amended during opposition proceedings in such a way as to extend the protection conferred. This applies to all amendments including the change of the category of claim. In order to decide whether or not the change of the category in the patent in suit satisfies that requirement, it is necessary to compare the protection conferred by the category of claim before amendment, i.e. as granted, with that of the new category of claim after amendment (see decision G 2/88, loc cit., points 3.2. and 4.1 of the reasons).

4.3.1. The protection conferred by a claim directed to a process for preparing a product covers that process. Pursuant to Article 64(2) EPC, the product insofar as it is directly obtained by that process, is also protected. Hence, the same product, when obtained by any other process for preparing the product, is not within the scope of protection conferred by the process claim. In the present case, the process claim as granted, i.e. before the amendment to a product claim, confers protection to the process claimed and, exclusively, to the particular tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymethyl]methane directly obtained by the claimed process; that particular tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane, when obtained by any other process, is not protected by the claims as granted.

4.3.2. The protection conferred by a claim directed to a product per se, however, is absolute upon such product. The product claim, thus, confers protection to that product regardless of the process by which it is prepared (see decisions G 2/88, loc cit., point 5 of the reasons; T 402/89 of 12 August 1991, point 2 of the reasons; T 73/92 of 25 March 1996, point 7 of the reasons; the latter neither published in OJ EPO). Hence, the product, when obtained by any process of preparation, is also within the scope of protection conferred by the product claim. In the present case, the product claim of the patent in suit after amendment confers absolute protection to the particular tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane as defined therein. Thus, that particular tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane, obtained by any preparation process other than that defined in the process claims as granted, is also protected by the product claim as amended.

4.4. The Appellant attempted to overcome this objection in formulating the product claim as amended in the form of a product-by-process claim using the term "directly obtained". He argued that this formulation of the claim, borrowed from Article 64(2) EPC, restricted the protection conferred exclusively to that product which is directly obtained by the process of the claims as granted. The product claim as amended, thus, would not confer absolute product protection regardless of how the product was obtained, and did not extend the protection conferred by the claims as granted, a view which the Board does not share.

In the present case the claim as amended is a claim to a product even if the product is defined in terms of a process for its preparation. Thus, despite the fact that this product is characterized by the process for its preparation, the claim nevertheless belongs to the category of claim directed to a physical entity, i.e. a product (cf. point 4.2 above). A product-by-process claim is interpreted according to the jurisprudence of the Boards of Appeal as a claim directed to the product per se, since the reference to a process for its preparation serves only the purpose of defining the subject-matter for which protection is sought, which is a product. Whether or not the term "directly obtained" or any other term, such as "obtained" or "obtainable", is used in a product-by-process claim, the category of that claim does not change as it is directed to a physical entity and the subject-matter of that claim, for which protection is sought, remains the product per se (see decisions T 411/89 of 20 December 1990, point 2.2 of the reasons; T 407/90 of 3 November 1997, point 2.5.3 of the reasons; neither published in OJ EPO; T 19/90, OJ EPO 1990, 476, point 4.9.2 of the reasons). Therefore, irrespective of how a product-by-process claim is worded, it is still directed to the product per se and confers absolute protection upon the product, precisely as any other claim to a product per se. That product claim, hence, confers protection upon the product regardless of the process by which it is prepared. In the present case, irrespective of the wording of the product-by-process claim of the patent in suit as amended, that claim is directed to a physical entity, i.e the particular tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane, regardless of the process by which it is in fact prepared. Thus, the product-by-process claim as amended does extend the protection conferred by the process claims as granted.

4.5. Consequently, in the Board's judgement, the change of category from the claims as granted to the claim as amended extends the protection conferred. For these reasons, claim 1. offends Article 123(3) EPC and the main request is rejected.

First Auxiliary Request

5. Amendments (Article 123(2) and (3) EPC)

5.1. The Appellant has introduced the feature "wherein the mass is completely molten" into process claim 1 as granted. The Respondent 1 has objected to this amendment in view of Article 123(2) EPC since it was only disclosed in one example in combination with other particular features of that Example; the incorporation of that feature into the claim represented an undue generalisation to starting compounds, having any characteristics covered by that claim, and to any cooling method.

5.2. In order to determine whether an amendment offends against Article 123(2) EPC it has to be examined whether or not technical information has been introduced which a skilled person would not have objectively, i.e. directly and unambiguously, derived from the application as filed (see decision T 680/93 of 29 November 1994, point 2 of the reasons; not published in OJ EPO).

5.3. The feature "wherein the mass is completely molten" is disclosed in Example 1 on page 7, lines 7 and 8 of the application as filed. However, that feature merely defines the exact physical state of matter. This liquid state of matter is independent of any particular characteristics in the solid state of the starting compound used in Example 1, e.g. melting point and purity. The particular reaction temperature used in Example 1 would be considered inessential by the skilled reader in so far as the complete liquid state of matter is achieved. Hence, the feature of completely melting the mass is closely related neither to the characteristics of the starting compound to be melted used in that particular Example, i.e. its melting point of 122.5°C and its purity of 98.5% b.w., nor to the reaction temperature applied in that particular Example, i.e. 140°C.

The liquid state of matter is of course also independent of any particular cooling method following the melting. Consistently therewith, the application as filed on page 6, lines 2 to 4 discloses that sudden cooling can be obtained by any method known in the art.

Therefore the skilled person does not associate the feature objected to with other particular features in Example 1, neither with the particular characteristics of the starting compounds nor with the particular cooling method used therein, contrary to Respondent 1's submission.

5.4. In the Board's judgement, the skilled person is not presented with technical information, when reading claim 1 as amended, which is not directly and unambiguously derivable from the application as filed.

5.5. The Board concludes that claim 1 as amended does not extend the subject-matter claimed beyond the content of the application as filed, thus satisfying Article 123(2) EPC.

5.6. The incorporation of the additional feature "wherein the mass is completely molten" into claim 1 as granted brings about a restriction of the scope of the claims and, therefore, of the protection conferred thereby, which is in keeping with the requirements of Article 123(3) EPC.

6. Novelty

6.1. The Appellant and the Respondent 1 were divided on the matter whether or not the product tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane prepared according to the process claimed was novel over the disclosure of document (2). The Appellant argued that the product prepared in the process of the patent in suit was completely amorphous in contrast to the -crystal structure of the product in document (2), whereas the Respondent 1 submitted that the -crystal structure in document (2) was in fact amorphous.

6.1.1. Claim 1 of the patent in suit as amended defines the product tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane, prepared according to the process claimed, as being amorphous, as having a glass-transition temperature of from 40°C to 50°C, and as exhibiting no endothermic melting peaks from a temperature higher than 50°C to 200°C. All these product features specify that the product prepared has a completely amorphous structure, excluding even the presence of small amounts of crystals.

6.1.2. Document (2) discloses tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane and a process for preparing that product. The product is defined according to claims 1 and 2, and page 3, line 1, as having a -crystal structure. On page 11, last line, to page 12, line 3 that document states that "when said product was determined for the crystal structure by means of X-ray-diffraction spectrum according to the powder method, it was confirmed that it has a gamma-crystal structure" (emphasis added). The Examples 1 and 2 of document (2) back up that disclosure in stating on page 14, lines 6 and 7, and on page 14, last line to page 15, first line, that "the product was found to be a granule having a -structure according to X-ray-diffractometry". Hence, the product prepared in document (2) is explicitly taught to be of a crystal structure, precisely of the gamma-crystal structure. Document (2) even explicitly confirms the crystal structure of the product by means of a conventional X-ray-diffraction spectrum according to the powder method, a tailor-made method for identifying a crystal structure and for distinguishing that structure from an amorphous one. For these reasons, in the Board's judgement, document (2) discloses to the skilled person a crystal structure of the product prepared therein.

6.1.3. The Respondent 1 questioned the crystal structure of the product prepared in document (2) and submitted that this product was in fact amorphous. According to established jurisprudence, the Respondent 1, who is the Opponent, carries the burden of proof for the facts he alleges (see Case Law of the Boards of Appeal, edition 1996, section VI A, point 10.5). If a party, whose arguments rest on these alleged facts, is unable to discharge its onus of proof, it loses thereby.

6.1.3.1. To support his submission, the Respondent 1 argued that the low melting point of the product in document (2) of 49°C (page 11, paragraph 3), which was very similar to the glass transition temperature of the product in Example 1. of the patent in suit of 48 C, indicated both products to be identical. However, the product tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane is polymorphous, existing in various allotropic forms (see page 2, line 44 of the patent in suit), which was never contested by the parties. Therefore, the quasi identity of the melting point in document (2) with the glass-transition temperature specified in the patent in suit, on its own, does not necessarily result in the conclusion that both products do have identical morphology too.

The explicit teaching of a crystal structure in document (2) on the one hand and of an amorphous structure in the patent in suit on the other hand, shows that, on the contrary, the morphologies of both products are different.

6.1.3.2. The Respondent 1 submitted in view of Example 1 in document (2) that the process step of sudden cooling the molten mass automatically produced an amorphous product which was moreover reported to be transparent. However, his submission, that the product was inevitably amorphous due to that process step, lacks any evidence to support it. Nor is Respondent 1's suggestion that transparency is tantamount to an amorphous structure backed up by any evidence.

6.1.3.3. Furthermore, the Respondent 1 referred to document (12) to back up his submission, that the product prepared in document (2) was in fact amorphous. The former document disclosed a product, which was labelled gamma-crystal, but which was nevertheless described as non-crystalline and glassy, i.e. amorphous (page 12, lines 9 to 12; Figure 4). He projected the amorphous structure from document (12) to the product disclosed in document (2), labelled gamma-crystal likewise.

The Respondent 1's objection implies, that the product prepared in document (2) is identical to that prepared in document (12). He bases the assumed identity of those products exclusively on their identical label "gamma-crystal". However, there is no proof for that assumed identity. On the contrary, this allegation does not take into account the very different melting points of the products obtained in document (2) and in document (12): the former shows a melting point of 49°C (page 11, paragraph 3), the latter of 70°C to 80°C (comparative Example 6 in table 2 on page 26). Therefore, these products cannot be considered to be identical, irrespective of their label. Furthermore, they are prepared according to two very different processes: the former by sudden cooling of a melt as set out below, the latter by recrystallisation of a solution (see page 24, comparative Example 6).

Hence, the Respondent 1 failed to prove that the product prepared in document (12), labelled gamma-crystal, is identical to that prepared in document (2).

6.1.4. The Respondent 1, on whom the onus of proof rests for the facts he alleged, has submitted no experimental evidence relating to carrying out the process of document (2) to show that the product so obtained is indeed amorphous and, hence, identical to that prepared in the process of the patent in suit. In the absence of pertinent evidence, Respondent 1 has not discharged the burden of proof which is upon him, with the consequence that the Board cannot accept his submissions in this respect.

6.1.5. The Respondent 1 further argued that the products prepared in document (2) and in the patent in suit were necessarily identical since the processes for their preparation were identical too. The process of document (2) does not disclose the critical feature of completely melting the mass as set out in point 6.2 below. For these reasons Respondent 1's submission is not supported by the facts and is disregarded by the Board.

6.2. The Appellant and the Respondent 1 had also divergent views on the matter whether the process of document (2) disclosed implicitly the feature that the mass was completely molten.

Document (2) does not contain any explicit statement to a complete melt; nor is the feature implicitly disclosed in that document. According to the Examples of document (2) the starting compound is molten under heating at up to 47°C above its melting point before sudden cooling, without indicating how long this temperature is maintained. That document neither discloses prolonging the melting step for a determined or critical period of time. In the absence of any indication of the time, there is no basis for a finding that the compound was indeed completely molten in the sense of the patent in suit. As the Appellant submitted, the complete melt excludes the presence of even very small amounts of not molten seed crystals in the melt which would prevent an amorphous product from being obtained by sudden cooling. The difference between the process now claimed and that of document (2) is reflected in the different morphology of the products prepared in document (2), i.e. crystal, and in the patent in suit, i.e. amorphous. Therefore, document (2) does not implicitly disclose to the skilled person the feature of the process claimed to melt the mass completely.

6.3. In the Board's judgement, it follows from the above that the product prepared according to claim 1 of the patent in suit is amorphous, contrary to the product prepared in document (2), which has a crystal structure. Furthermore, that document lacks disclosure of the process feature to melt the mass completely. Thus, document (2) does not anticipate the subject-matter of the claimed invention.

6.4. The Board is satisfied that, for the same reasons, the subject-matter of the claimed invention is not disclosed in any of the further cited documents either. This being not in dispute between the parties during appeal proceedings and the Opposition Division having already acknowledged novelty for the present claims, it is not necessary to give detailed reasons for this finding.

6.5. Therefore, the Board concludes that the subject-matter of the patent in suit is novel and meets the requirements of Articles 52(1) and 54 EPC.

7. Inventive step

7.1. In accordance with the "problem-solution approach" consistently applied by the Boards of Appeal to assess inventive step on an objective basis, it is necessary to establish the closest state of the art being the starting point, to determine in the light thereof the technical problem which the invention addresses and solves, and to examine the obviousness of the claimed solution to this problem in view of the state of the art.

7.2. The patent in suit aims at preparing a tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane which is amorphous and has a glass-transition temperature (Tg) of up to 50 C. A product having these characteristics already belongs to the state of the art. In Example 2(a), document (1) teaches the preparation of that product, reportedly being a clear amber glass, which softens from 50 C (page 6, line 13). As generally known, the characterisation of the product as being a glass is tantamount to an amorphous structure. The amorphous product is prepared in document (1) by treating a solution of tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane, obtained from the conventional transesterification process, and finally evaporating the solvent. The document (6) is identical to document (1) and therefore concerns the same teaching.

The Board considers, in agreement with the Appellant, that this state of the art represents the closest one, since it aims at preparing a product with precisely the characteristics as indicated in the patent in suit, i.e. amorphous and a low softening point of 50 C. The Board observes that in the present case, where the invention lies in a process for preparing a tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymethyl]methane having known characteristics, the closest prior art is that document which discloses said product having precisely those characteristics together with a process for the preparation thereof. This assessment reflects objectively the factual situation of the person skilled in the art at the priority date of the patent in suit.

Moreover, document (1) has been acknowledged in the patent in suit as relevant prior art relating to glassy solids with a softening point of 50 to 60°C (page 2, lines 18 and 34), and hence, as starting point of the claimed invention.

The Respondent 1 submitted that the disclosure of document (2) was to be considered as closest prior art and thus as starting point in the assessment of inventive step. It referred to a process comprising the sudden cooling of a melt of tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane; therefore these process features came closest to the claimed process. However, that document relates to the preparation of a crystal product as set out in very detail in point 6.1 above. Thus, contrary to document (1), document (2) does not refer to the preparation of an amorphous product as does the patent in suit. The Board concludes therefore that the latter document represents state of the art being further away from the patent in suit than documents (1) and (6).

7.3. In the next step the technical problem which the invention addresses in the light of the closest state of the art is to be determined.

In view of the closest state of the art, i.e. document (1), the technical problem underlying the patent in suit can only consist in providing a further process for preparing tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymethyl]methane in in amorphous form, while retaining the low softening point.

7.5. The specification of the patent in suit demonstrates e.g. in Example 1 that the claimed process achieves an amorphous product and a low softening point, i.e. solves the problem defined above. According to page 4 lines 41 to 45 of the patent in suit, the X-Ray Check of the product obtained results in the diffraction spectrum shown in Figure 3, which proves the product to be amorphous. The Viscosity Check on page 4, lines 54 to 56 in combination with page 3, lines 15 to 29 of the patent in suit, wherein the viscosity of the amorphous product is measured within a temperature range of from 80°C to 120°C, demonstrates additionally the stability of the amorphous form. According to page 4 lines 23 to 39 of the patent in suit, the DSC Check of the product obtained yields an endothermic melting peak at 48°C, which proves the product to have a low softening point.

For these reasons, the Board is satisfied that the problem underlying the patent in suit has been successfully solved. This finding has not been challenged by the Respondent 1.

7.6. It remains to decide whether or not the proposed solution to the problem underlying the patent in suit is obvious in view of the state of the art.

7.6.1. Document (2) teaches a process for preparing tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane having a crystal structure (see point 6.1 above). Thus, it does not address the problem underlying the patent in suit, i.e. to provide a process for preparing an amorphous product (see point 7.3 above). Consequently, document (2) cannot give any hint on how to solve that problem.

The process disclosed in document (2) comprises a melting step without, however, neither disclosing the process feature of the process claimed to melt the mass completely, nor suggesting that feature to be critical (see point 6.2 above). To achieve a complete melt, as already pointed out above, represents a critical process feature since it excludes the presence of even very small amounts of remaining, not molten seed crystals in the melt which would prevent an amorphous product to be obtained by sudden cooling.

For these reasons, in the Board's judgement, document (2) does not render obvious the proposed solution to the problem underlying the patent in suit.

7.6.2. In comparative Example 6 on page 24, document (12) teaches a process for preparing tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) -propionyl-oxymehyl]methane having an amorphous structure (see point 6.1.3.3 above). The disclosed process comprises the treatment of a solution of that product including a recrystallisation step. Therefore, the process of document (12) is substantially different to the claimed process comprising the sudden cooling of a complete melt.

For these reasons, document (12) also does not give any pointer to and does not render obvious the claimed solution, either taken alone or in combination with document (2).

7.6.3. The Respondent 1 not relying on further documents in order to object to obviousness, the Board is satisfied that none of the other documents in the proceedings renders the proposed solution obvious.

7.7. For these reasons the Board concludes that the subject-matter of claim 1, and by the same token, that of dependent claims 2 to 4 involves an inventive step within the meaning of Articles 52(1) and 56 EPC.

Second Auxiliary Request

8. Since the preceding first auxiliary request is allowable for the reasons set out above, there is no need for the Board to decide on the second auxiliary request being of lower order.