T 0064/03 (Polytetrafluoroethylene dispersions/DAIKIN) 01-02-2005

Summary of Facts and Submissions

I. Mention of the grant of European patent No. 0 818 506 in respect of European patent application No. 96906946.7 in the name of Daikin Industries, Limited, was announced on 31 May 2005 on the basis of 5 claims. Claim 1 read as follows:

"An aqueous polytetrafluoroethylene dispersion composition characterized in that the composition comprises 30 to 65 wt. % of polytetrafluoroethylene and a polyoxyethylene alkyl ether in an amount of 2 to 10 wt. % based on the polytetrafluoroethylene, the polyoxyethylene alkyl ether being represented by the formula

RO(CH2 CH2O)nH

wherein R is a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms, and n is 5 to 18, having a cloud point of over 45 °C to not higher than 85 °C and containing 65 to 70 wt. % of ethylene oxide in the molecule."

The granted claims further contained an independent claim 3 directed to an article prepared by coating a base material with the composition of claim 1, an independent claim 4 directed to a binder for batteries containing the composition of claim 1 and an independent claim 5 directed to a coating composition comprising a dispersion as defined in claim 1 and a pigment. Claim 2 was dependent on claim 1.

II. Notices of Opposition, requesting revocation of the patent in its entirety on the grounds of Article 100(a) EPC were filed on 23 February 2001 by Ausimont S.p.A (Opponent I) and on 27 February 2001 by Dyneon LLC (Opponent II).

III. The oppositions cited inter alia the documents

D1: US-A-3 704 272 (corresponding to JP-B-21532/1977);

D8: "Nonionic Surfactants", M.J. Schick (Ed.); Dekker, New York, 1967, pp. 72-85, 102-125, 138-141, 570-583;

D14 consisting of:

D14a: Parant, B., "Index- the Non-Ionic Surfactants", page 86 (date given by OI as October 1988);

D14b: Hoechst Datasheet E-HOE 5027 D/E, August 1992 "Genapol X Grades", pages 1-5; and

D14c: Genapol X-080 datasheet (March 1991);

D1 being cited by both Opponents in their notices of Opposition; D8 being cited by OI in the Notice of Opposition and D14a-c being cited by OI in the submission of 28 August 2002.

IV. By its decision announced orally on 29 October 2002 and issued in writing on 14 November 2002 the Opposition Division revoked the patent.

The decision of the Opposition Division was based on a main and an auxiliary set of claims submitted in writing on 28 August 2002 and 25 October 2002 respectively.

Claim 1 of the main request differed from claim 1 as granted by replacement of the term "polyoxyethylene alkyl ether" with "ethoxylated aliphatic alcohol".

Claim 1 of the auxiliary request was further amended by raising the lower limit of ethylene oxide (EO) content to 65.5 wt%.

Claims 2-5 of both requests corresponded to claims 2-5 as granted.

The Opposition Division found that the amendments made met the requirements of Article 123(2) EPC. Contrary to the position taken by Opponent II, the Opposition Division did not consider that the amended term "ethoxylated aliphatic alcohol" was disclosed only in the context of a discussion of the prior art. Further it was not considered that there was any inconsistency between this term and the possibility - explicitly recited in claim 1 - that the substituent group R may contain unsaturation. On the contrary, it was considered that the original wording was open to such an objection. It was held, with reference to page 2 lines 34 and 56 of the patent in suit, that the skilled person knew that these terms were equivalent. It was also held that it became clear from page 3, line 1 of the patent in suit that it was not the intention to encompass surfactants containing aromatic groups. Further it was found that suitable groups R (saturated and unsaturated) were disclosed at page 3, line 39 and in examples 1-4 of the patent in suit.

The patent in suit was revoked on the grounds that the it did not meet the requirements of Article 83 EPC.

Both Opponents had, independently and with different reasoning, raised this ground at a late stage of the proceedings: Opponent I with letter of 28 August 2002 and Opponent II during the Oral Proceedings before the Opposition Division.

The arguments of Opponent I were disregarded as being late filed and of no relevance.

The Opposition Division took account, however, of the arguments of Opponent II which it found convincing.

These can be summarised as follows:

- the cloud point was an essential feature of the claimed subject matter;

- the patent did not disclose the method or the measurement conditions (concentration, solvent) by which this was to be determined;

- in the case of mixtures of surfactants the patent did not disclose whether the cloud point was determined on the mixture or on the individual surfactants;

- it was known from the prior art, in particular D8 and D14 (especially D14b), that there were many methods for determining the cloud point, employing different conditions of concentration of solvents, and that these measurements were "appreciably" influenced by the presence of additives; and

- the results could diverge by up to 30°C (based on D14c).

The counter arguments of the Patentee that:

- it was clear from paragraphs [0007] and [0019] of the patent in suit that the method of D1 was that to be employed;

- D1 represented the starting point of the present invention; and

- the method of D1 was the most common one

were not found convincing.

In particular the Opposition Division held that there was no hint or suggestion in the patent in suit that the cloud point should be measured in accordance with the disclosure of D1.

The Patentee requested rejection of the new ground pursuant to Article 114(2) EPC as late filed.

After a break in the Oral Proceedings, the Division asked the Patentee whether the method of D1 corresponded to a standard (ASTM, JIS, DIN), which the Patentee was not able to confirm. Thereupon the decision revoking the patent on this new ground was announced.

V. On 10 January 2003, the Patentee (Appellant) lodged an appeal against the decision of the Opposition Division and paid the Appeal fee on the same day. Maintenance of the patent on the basis of the claims filed on 28. August 2002 (Section IV above) was requested. As an auxiliary measure, appointment of Oral Proceedings was requested.

VI. The Statement of Grounds of Appeal was submitted on 24. March 2003 together with a copy of European Standard EN 1890 and an experimental report.

The arguments presented by the Appellant in the Statement of Grounds of Appeal which are relevant for this decision may be summarised as follows:

(i) The ground on which the patent had been revoked had not been raised in the opposition statements of either opponent.

(ii) The objection of Opponent I under this "fresh" ground, submitted with letter of 28 August 2002 had been deemed belated and irrelevant and hence not admitted.

(iii) The objection of Opponent II under this "fresh" ground was based on entirely different facts and submitted at an even later stage (one hour into the Oral Proceedings). It had been admitted despite the request of the Appellant to reject it. The Patentee had been accorded around 25 minutes to consider this.

(iv) Instead of revoking the patent, the Division should have rejected the fresh ground, or accorded the Appellant sufficient time to explain the technical background.

This was a blatant violation of the principle of due process and justified setting aside the decision.

(v) The Appellant had explained in the Oral Proceedings before the Opposition Division that the most common method for determining the cloud point of polyoxyethylene alkyl ether surfactants was in a 1% aqueous solution. Opponent I had confirmed this at the Oral Proceedings, however this statement was absent from the minutes.

VII. The arguments presented by Respondent I (Opponent I) in the letter dated 15 October 2003 and Respondent II (Opponent II) in the letter dated 10 September 2003, as far as they are relevant for this decision, may be summarised as follows:

(a) Respondent I:

(i) The objection under Article 83 EPC was based on the fact that while the cloud point was stated by the Appellant to be an essential feature, and was necessary to ascertain which components were suitable, no method to determine this was disclosed in the patent in suit. The evidence of the Appellant showed that there was no reliable way to find out which method needed to be used, so the skilled person would not know how to determine this. It was considered that in such a situation, it was inappropriate to consider that there had been a "blatant violation" of the principle of due process.

(ii) It was also considered that any attempt to make a comparison between a known method and the values given in the patent was pointless since it was not known which method was employed in the patent.

(iii) The Appellant had used the time that he considered sufficient for his argumentation, and the time available to him was not limited by the Opposition Division.

(b) Respondent II:

(iv) The raising of this new ground of opposition was a result of the experimental evidence filed by the Patentee with letter of 25. October 2002, 4 days before the oral proceedings. This evidence established that the correlation between cloud point and ethylene oxide (EO) content for the same compound varied between different manufacturers.

(v) Prior to this evidence being submitted, the Opponents had assumed and argued that the cloud point and EO content were directly linked such that one could be inevitably and directly derived from the other. It was the evidence of the Patentee that cast doubts on this assumption, in particular since this showed that there would be a substantial difference between the cloud point of the same compound provided by different suppliers.

VIII. The Board issued, on 16 November 2004, a communication accompanying a summons to attend Oral Proceedings.

(i) According to the communication, it appeared that the amended claims of 28 August 2002 were not supported by the disclosure of the application as filed, contrary to Article 123(2) EPC. The occurrence of the term "ethoxylated aliphatic alcohol" in paragraph [0004] of the patent appeared to relate to a discussion of the prior art and not to the subject matter of the patent in suit. The original term appeared to be more precise than the amendment. As this was a substantive amendment, it had to be examined for compliance with Article 84 EPC. An inconsistency was seen between the use of the term "aliphatic alcohol" and the definition of R as being a saturated or unsaturated group of non-restricted nature, i.e. this definition included aromatic unsaturation whereas the term "aliphatic alcohol" excluded such species.

Due to this lack of clarity, it furthermore appeared unlikely that the amendment would fulfil the intended purpose of overcoming an objection of lack of novelty with regard to prior art compositions containing aromatic compounds.

(ii) With regard to the revocation on the ground of Article 100(b) EPC, it was observed that it was not apparent from the Minutes that any decision to admit the new ground and hence to refuse the request of the Patentee for its exclusion pursuant to Article 114(2) EPC had been separately announced, although it was derivable from the Minutes and the Decision of the Opposition Division that this ground had de facto been admitted into the proceedings.

The Parties were informed that the Board would examine whether the objection of the Appellant that the ground pursuant to Article 100(b) had been raised in such manner as to deprive it of a proper opportunity to present comments on this was justified, and that, if the Board concluded this was the case the case would in all likelihood be remitted to the Opposition Division for further prosecution without the Board taking position on the substantive merits of this ground of opposition. With regard to the appropriate procedure to be followed by an Opposition Division in such a situation, the Board cited decision T 433/93 (OJ EPO 1997, 509).

IX. The Appellant responded in a letter dated 24 December 2004, arguing essentially as follows:

(i) With regard to Article 123(2), 123(3) and 84 EPC it was submitted that the presentation of the terms "ethoxylated aliphatic alcohol/polyoxyethylene alkyl ether" in paragraph [0004] of the patent and on page 2, line 34 of the application indicated that the term was not a quotation from the prior art but showed that these terms were equivalent. It was acknowledged that according to the original wording the nature of the R group remained unclear. It was submitted that the amended wording "ethoxylated aliphatic alcohol" restricted the R group to an aliphatic group which could include ethylenic unsaturation, but not aromatic saturation. Hence the amended claim was more restricted than granted claim 1.

(ii) With respect to Article 113(1) EPC, the Appellant requested remittal to the first instance for further prosecution. The arguments as set out in the Statement of Grounds of Appeal were essentially repeated.

(iii) An auxiliary request for maintenance of the patent on the basis of 5 claims corresponding to those of the granted patent, however with the meaning of substituent R being unsaturated being deleted was proposed. The text of this request was not presented with the letter.

X. Oral proceedings were held before the Board on 1. February 2005.

During the Oral Proceedings the Appellant formally submitted the auxiliary request foreshadowed in the submission of 24 December 2004.

A. With regard to the alleged procedural violation:

(a) the Appellant submitted that he had been taken by surprise by the conduct of the Opposition Division and had not been prepared for a discussion on the issue of determination of the cloud point. In particular:

(i) The Appellant considered he had made only preliminary remarks on admissibility, with the aim of convincing the Division to disregard the new objection. He had consequently expected initially a decision on the relevancy/admissibility of the new ground, prior to any discussion on the merits thereof. The Opposition Division had, however, combined the debate on admissibility/relevancy and merit into one.

(ii) The absence of a separate decision on admissibility had deprived the Appellant of an opportunity to deal with the substance of the ground, and to discuss this with the experts of the Appellant who were present at the Oral Proceedings before the Opposition Division and, if necessary, to request that the procedure be continued in writing.

(iii) The Appellant emphasised the need legally to separate the discussions on relevancy and merit. If the new ground had been found to be relevant, then it would have been necessary to allow a continuation of the procedure to consider the merit. In the context of the present Appeal proceedings, this would have meant remittal to the first instance due to the principle that parties are entitled to decisions at two levels (reference made to T 1075/01 (22 October 2004, not published in the OJ EPO) and T 326/87 (OJ EPO 1992, 522)).

(iv) On the question of relevancy of the new ground, the patent in suit represented a selection from the disclosure of D1 and hence everything disclosed in D1 applied also to the patent in suit. In support of this reference was made to paragraphs [0004], [0007], [0019] and [0022].

(b) The Respondents submitted that everything relevant to the question of Article 100(b) in relation to the cloud point determination had been discussed, and that the Appellant had been given every opportunity to comment on this. It was also apparent from the Appellant's submissions that he considered that the question of relevance of this new ground had been fully discussed. The Appellant could have requested an opportunity to make further submissions - even if not expressly invited to do so.

In particular:

(i) It should have been clear to the Appellant that the Opposition Division considered the reasons serious and intended to take a decision on this.

(ii) It was submitted with reference to T 484/89 (8 December 1992, not published in OJ EPO) that "opportunity" was not to be equated with "time", but "possibility". The Appellant had had the possibility to make submissions or request more time, e.g. continuation of the proceedings in writing, but did not. It was not considered that there was any need for separate decisions on admissibility/relevance and merit of the new ground as these issues were intimately linked, the arguments put forward in favour of admitting the new ground equally applying to its merits.

(iii) In any case it was disputed that this was really a new ground. Rather, and by analogy with G 9/91 and G 10/91 (OJ EPO 1993 408 and 420) it was argued that a new line of argumentation by the Appellant resulting in a change in the interpretation of the claims meant it was justified to examine the claims for compliance with all provisions of the EPC.

(iv) It was argued that T 433/93, cited in the Communication of the Board, was not relevant as this decision dealt with the case in which a new ground which had never previously been in the proceedings was raised.

(v) On the substance of the objection, it was argued that the evidence of 25 October 2002 showed that it was not possible to understand what was meant by the cloud point, essentially repeating the arguments put forward in the written procedure. The submission of the Appellant at the first instance Oral Proceedings and at the Proceedings before the Board of Appeal that the method of D1 was the applicable one was contradicted by the statements and evidence filed with the Statement of Grounds of Appeal, showing that the Appellant considered that other methods could be applicable.

B. With regard to the admissibility of the amended claims according to the main request under Article 123(2) and (3) EPC:

(a) The Appellant repeated the argument that the patent in suit was derived from D1 (with reference to paragraphs [0004]-[0007] of the patent).

(i) The terms employed were synonymous as would be clear to the skilled reader from the reference to D1. The amendment had been undertaken to overcome a lack of clarity which arose due to a peculiarity of the manner in which claims were interpreted according to EPC practice, i.e. without employing the description to elucidate the scope.

(ii) It was inherent in the disclosure of the patent in suit that aromatic substituents on the surfactant were undesired, and hence a reasonable reading of the claim would exclude this possibility. While it was acknowledged that there was a certain discrepancy between the definition of the surfactant and the possibility that the group R can be saturated or unsaturated, the skilled person would interpret this in the light of the description of the patent in suit to exclude aromatic groups. In any case the formula would be given precedence over the nomenclature. The Chairman observed that this meant that aromatic groups would mandatorily fall under the claim.

(iii) With regard to the meaning of the term "alkyl" it was argued that the term as employed in the art did not necessarily require "alkyl" groups in the strict sense but covered R groups that could have both unsaturation and alkyl in part. The nature of the R group would be elucidated e.g. by reference to D1.

(b) The Respondents argued that:

(i) the term "ethoxylated aliphatic alcohol" was broader than the original term "polyoxyethylene alkyl ether". The latter term meant that mandatorily a saturated alkyl residue must be present in the molecule, e.g. the terminus must be of the form CnH2n+1 even if between this group and the polyoxyethylene functionality there were other types of aliphatic groups, e.g. ethylenically unsaturated units. In contrast, the wording of the suggested amendment did not place any such restriction on the molecule meaning e.g. that an ethoxylated unit containing terminal vinyl functionality would be encompassed, rendering the revised wording broader than the original term.

(ii) Respondent II illustrated this as follows:

The residue

CH3-CH=CH-CH2-CH2-O

would be considered as an "alkyl ether" due to the terminal methyl group.

However, the residue

CH2=CH-CH2-CH2-O

would not be considered as an "alkyl ether" since there was no alkyl group in this.

C. With regard to the auxiliary request of the Appellant, neither Respondent raised any objection pursuant to Article 123(2) and (3) EPC. Respondent II considered that the amended claim potentially did not meet the requirements of Article 84 EPC since it was not clear whether the cloud point was solely due to this compound or to the presence of some other additive. It was also observed that it would be necessary to ensure that further statements in the description, e.g. paragraph [0016] would be limited to the formula in the claim.

XI. The final requests of the parties were:

Appellant (Patentee):

That the decision under appeal be set aside and that the case be remitted to the first instance for further prosecution on the basis of claims 1 to 5 filed with letter dated 28 August 2002 (main request), or in the alternative on the basis of claims 1 to 5 filed at the oral proceedings as auxiliary request.

Both Respondents (Opponents):

That the appeal be dismissed.

Respondent II further requested auxiliarily:

That, in case of remittal of the case to the first instance, that the Opposition Division should be obliged to base the further prosecution only on the facts and evidence already on file.