T 0412/03 (Fluoromonomers/DU PONT DE NEMOURS) 16-06-2005

Reasons for the Decision

1. The appeal is admissible.

Main request

2. Article 84 EPC

2.1. Claim 4 is drafted as a product claim related to Claim 2 itself related to Claim 1. Claim 4 is thus a dependent claim incorporating the features of the product Claims 1 and 2.

In Claim 1, the divalent chain Rf is defined inter alia as perfluoroalkyleneoxy having 1-20 carbon atoms and in Claim 4, Rf is -[O-CF2CF(CF3)]k-O-CF2CF2-, with k is 1-5 (see point II above).

2.2. In order to understand the origin of the term "perfluoroalkyleneoxy" found in the present Claim 1, but not in the application as originally filed which uses the term "perfluoroalkyloxy", the Board finds it necessary to briefly refer to the file history.

2.2.1. The IPEA had already objected under Article 6 PCT (Article 84 EPC) to the term "perfluoroalkoxy" in that it did not fit the definition of Rf since in the compound of formula (I) Rf was a divalent group (see IPER, Item VIII). The Examining Division had taken up this objection in its first communication.

2.2.2. The Appelant had filed in response an amended Claim 1, wherein inter alia "perfluoroalkoxy" was replaced with "perfluoroalkyleneoxy". A communication under Rule 51(4) EPC followed (see point VI above), suggesting, therefore, that the replacement had been accepted by the Examining Division. In the decision under appeal, the Examining Division stated that this change was due to the correction of an obvious error (see page 2, third paragraph). The Board can only conclude therefrom that the correction was made under Rule 88 EPC which provides that errors may be corrected on request provided that the correction is obvious in the sense that it is immediately evident that nothing else would have been intended than what is offered as the correction.

2.2.3. In its decision dated 22 November 2002, the Examining Division offered a definition of the term "perfluoroalkyleneoxy" in the following terms:

"The bivalent group Rf as defined in the only remaining request represents perfluoroalkylene or perfluoroalkyleneoxy moieties having 1 to 20 carbon atoms. This means a divalent carbon chain bearing only fluorine atoms, and, in the second alternative being linked at the "right end" of the Rf group in the formula of Claim 1 to the "right part" of said formula through the oxygen atom".

2.3. In appeal, the Appellant contested however the definition given by the Examining Division on the ground that the situation was not as clear cut as the decision made out and that the correct context in which alkoxy and the alkyleneoxy are used was critical to determine their meanings.

2.4. It has to be, therefore, investigated in the present case whether or not the definition of Rf according to Claim 4, i.e. -[O-CF2CF(CF3)]k-O-CF2CF2-, wherein k is 1-5 is within the general definition of Rf given in Claim 1, i.e. perfluoroalkyleneoxy.

2.4.1. First, the Appellant argued that in view of the description of the European patent application, the term "alkyleneoxy" should be construed more broadly as usual to include the groups of Claim 4. It was clear, in particular, that in view of page 2 of the application as originally filed perfluoroalkoxy (subsequently corrected to perfluoroalkyleneoxy) included -[O-CF2CF(CF3)]k-O-CF2CF2-, with k is 1-5.

However, such an approach is not in line with the clarity requirement of Article 84 EPC. That clarity requirement in fact relates only to the claims, and consequently, as the Boards of Appeal of the European Patent office have consistently ruled, it demands that these be clear per se for a person skilled in the art with common general knowledge of the technical field in question, without the need to refer to the description of the patent application (see T 2/80, OJ EPO 1981, 431, point 2; T 1129/97, OJ EPO 2001, 273, point 2.1.2; T 172/02, point 4.1 and T 412/02 point 5.6).

For this reason the Appellant cannot rely on the description of the European patent application and his argument in that respect is not accepted.

2.4.2. The claims must be read by a skilled reader. The Board, therefore, does not reject prima facie any piece of information in the form of common general knowledge which could throw light on the meaning of the term at issue. Textbooks may, in particular, be referred to.

2.4.3. Document (10) cited by the Appellant discloses the following (verbatim):

"Such compounds have been shown to be effective foam depressants and an example based on poly(propylene glycol) (PPG) and PEG is shown in Figure 17.16. By varying the number and types of substituents (fatty alcohol, alkyleneoxy group, end blocking, etc.) the properties of the ortho-ester-based surfactant or block copolymer can be tailor-made for a specific field of application"

FIGURE 17.16

However, in contrast with the Appellant's submission, the term "alkyleneoxy" according to this piece of document refers, in the Board's judgment, to the units of the type -(CH2CH2O)-, -(CH2CH(CH3)O)-, the number of which, i.e. the "m" figure, may vary. The term "alkyleneoxy" means, in that context, a divalent uninterrupted hydrocarbon chain having on the right end one oxygen atom.

In view of this document, the Board comes unavoidably to the following conclusions:

(a) A radical -O-CF2CF(CF3)- or -O-CF2CF2- cannot be within the meaning of perfluoroalkyleneoxy since the oxygen atom in the formulae of those radicals is on the left end. This distinction is of the greatest importance in the present case in view of the non symmetrical nature of the compound of formula (I).

(b) Secondly, Rf according to Claim 4 having possibly a plurality of oxygen atoms interrupting the alkylene chain, it cannot also for this reason fit the definition of the term "alkyleneoxy".

That finding confirms the definition given by the Examining Division (see point 2.2.3 above) and it turns out that far from supporting the Appellant's position, it leads to the conclusion that the term perfluoroalkyleneoxy of Claim 1 cannot be reconciled with the formula of Claim 4 in view of document (10).

2.4.4. According to the document (11) cited by the Board in its second communication, the perfluoropolyethers with the linear perfluoropropoxy repeat units have the formula:

C3F7O(C3F6O)nC2F5

In the present case, the divalent unit C3F6O is named perfluoropropoxy (perfluoropropyleneoxy after correction) and it derives therefrom that the term "perfluoropropyleneoxy" must be read from left to right and consists of a structure composed of three uninterrupted methylene radicals having on the right end one oxygen atom. It follows from that document that the radical Rf of formula -[O-CF2CF(CF3)]k-O-CF2CF2- wherein k is 1-5 cannot fit the generic definition of perfluorolakyleneoxy since the oxygen atom is on the left end of the chain inside of which a plurality of oxygen atoms are present.

2.4.5. The Appellant also relied on the seven patent documents (1) to (7). However patents are not part of the common general knowledge of the skilled reader, in contrast to textbooks. The sole exception in that respect being the case where there are no available textbooks due to the recent character of the field of research (see T 51/87, OJ EPO 1991, 177). Handbooks are available in the present case and, therefore, the exception does not apply.

2.4.6. The Appellant also argued relying upon documents (8) and (9) that the term "perfluoroalkyleneoxy" included groups containing low numbers of oxygen atoms. The Examining Division was, therefore, wrong to consider that the group Rf is [O-CF2CF(CF3)]k-O-CF2CF2- wherein k is 1-5 was to be defined as a polyoxyalkylene not included in the generic term "perfluoroalkyleneoxy". The term "poly" was used to denote "many" which was not the case for the group Rf according to Claim 4.

The Board does not deny that the suffix "poly" means "many" (see document (8), page 3, bottom paragraph). This does not alter the fact that the group [O-CF2CF(CF3)]k-O-CF2CF2- is a low-molecular-weight polymer group (emphasis added by the Board) made of repeating units [O-CF2CF(CF3)] as it derives clearly from document (9), page 8, lines 1 to 11. It follows that the group [O-CF2CF(CF3)]k-O-CF2CF2- is a polyperfluoroalkyleneoxy not included in the generic definition of perfluoroalkyleneoxy.

The Board concludes for this reason also that the definitions of Rf of Claims 1 and 4 cannot be reconciled.

2.4.7. In view of the above, the Board finds that the definition given by the Examining Division is convincing (see point 2.2.3 above) and that there is a contradiction between Claim 1 which relates to a compound of formula (I) wherein Rf may be perfluoroalkyleneoxy and Claim 4 wherein Rf is -[O- CF2CF(CF3)]k-O-CF2CF2- wherein k is 1-5.

2.5. However, according to Article 84 EPC the claims must be clear and concise and define the matter for which protection is sought. The clarity requirement of Article 84 EPC demands that the claims must be free of contradiction as such. A clear wording of the claims is for legal certainty indispensable. That requirement serves the purpose of ensuring the public is not left any doubt as to which subject-matter is covered by any particular claim (see T 2/80, OJ EPO 1981, 431, point 2 and T 172/02, point 4.1).

2.6. Since this requirement is not met by the claims, the present request must be refused.

2.7. This leads the Board to observe, as a final remark, that this finding casts doubt on the allowability of the correction under Rule 88 EPC (see point 2.2.2 above). Indeed, a correction under Rule 88 EPC is only to be accepted if it is immediately evident to a skilled person that a) an error occurred and b) how it should be corrected which implies that such a correction must not raise any contradiction liable to contravene the requirement of Article 84 EPC. This is however the case here. According to the Appellant's own words the situation generated was not so "clear cut as the decision made out". In the Board's judgement, a correction under Rule 88 EPC must lead, on the contrary, to a clear cut situation generating no contradiction.

First auxiliary request

3. Claim 3 is drafted as a product claim related to Claim 2 itself related to Claim 1. Claim 3 is thus a dependent claim incorporating the features of the product Claims 1 and 2.

In Claim 1, the divalent chain Rf is defined inter alia as perfluoroalkyleneoxy having 1-20 carbon atoms, or - [O-CF2CF(CF3)]k-O-CF2CF2- and k is 1-5 and in Claim 3 Rf is O-(CF2)m and m is 2-4 (see point VIII above).

3.1. In the present case, the question arises whether or not the definition of Rf according to Claim 3 is within the general definition of Rf given in Claim 1, i.e. perfluoroalkyleneoxy.

3.2. In view of documents (10) and (11) as common general knowledge (see points 2.4.3 and 2.4.4 above), it turns out that a perfluoroalkyleneoxy chain is a divalent carbon chain bearing only fluorine atoms and being linked at the "right end" of the Rf group, in the formula of Claim 1 to the "right part" of said formula, through the oxygen atom". It follows that a bivalent group O-(CF2)m cannot be considered as a perfluoroalkyleneoxy radical. This distinction is of the greatest importance in view of the non symmetrical nature of the compound of formula (I). There is, therefore, a contradiction between Claims 1 and 3 contrary to the requirement of Article 84 EPC (see point 2.5 above).

3.3. Since the clarity requirement is also not met by these claims, this request must be refused as well.

Second auxiliary request

4. Article 123(2) EPC - Rule 88 EPC

4.1. Compared to Claim 1 as originally filed, present Claim 1 was, first, amended to replace perfluoroalkyl by perfluoroalkylene and to delete the term perfluoroalkoxy.

There is no support in the application as originally filed for amending perfluoroalkyl to perfluoroalkylene.

However Rf is a bivalent radical. According to IUPAC, univalent radicals derived from saturated unbranched acyclic hydrocarbons by removal of hydrogen from a terminal carbon atom are named by replacing the ending "ane" of the name of the hydrocarbon by "yl". (see IUPAC, Organic Chemistry Division, Nomenclature of Organic Chemistry, 1979 edition, J. Rigaudy and S.P. Klesney, page 5, paragraph 1.2). An error must thus have occurred in the application as filed since Rf cannot be an univalent radical.

It is generally known in chemistry that names of bivalent radicals derived from normal alkanes by removal of a hydrogen atom from each of the two terminal carbon atoms of the chain are ethylene, propylene, tetramethylene, pentamethylene, etc (see IUPAC, Organic Chemistry Division, Nomenclature of Organic Chemistry, 1979 edition, J. Rigaudy and S.P. Klesney, page 14, paragraph 4.2).

It derives therefrom that the replacement of the term "perfluoroalkyl" by "perfluoroalkylene" is an obvious correction allowable under Rule 88 EPC in the sense that it is immediately evident that nothing else would have been intended than what is offered as the correction (see T 532/95, point 3.2.1). Such a correction does not contravene furthermore Article 123(2) EPC (see G 3/89 and G 11/91, OJ EPO 1993, 117 and 125, Order).

4.2. The added feature in Claim 1, i.e. Rf is or -[O-CF2CF(CF3)]k-O-CF2CF2- wherein k = 1-5 or O-(CF2)m wherein m is = 2-20, finds support in the description as originally filed (see page 2, lines 28-29).

4.3. The subject-matter of Claims 2 to 16, 18 and 19 corresponds to Claims 2 to 16, 18 and 19 as originally filed respectively. The subject-matter of Claim 17 finds support in the description as originally filed (see page 10, lines 26 to 29 and page 11, lines 10-11.

4.4. There is, therefore, no objection under Article 123(2) EPC.

5. Article 84 EPC

5.1. The phrase "Rf is perfluoroalkoxy" having been deleted, the objection raised against the claims of the main and first auxiliary requests (cf. points 2 and 3 above) does not apply any longer. Indeed, the subject-matter of Claim 1 relates to compounds of formula (I) wherein Rf may have three distinct alternative meanings and the subject-matter of Claims 3 and 4 is without any doubt within that of Claim 1. The definitions of the compounds according to Claims 1 to 19 are furthermore clear.

5.2. There is, therefore, no objection under Article 84 EPC.

6. Remittal to the first instance - Article 111(1) EPC

6.1. The Board has come to the conclusion that the subject- matter of Claims 1 to 19 according to the second auxiliary request complied with the clarity requirement overcoming, therefore, the sole reason for revoking the European Patent relied on by the first instance.

6.2. Given that the function of the Boards of Appeal is primarily to give a judicial decision upon the correctness of the earlier decision taken by the first instance, the Board exercises its discretion under Article 111(1) EPC to remit the case to the first instance for further prosecution.