T 0196/13 (Specialty cellulose pulp/Borregaard) 04-03-2016

Summary of Facts and Submissions

I. The appeal by the Opponent lies from the interlocutory decision of the Opposition Division concerning maintenance of European Patent No. 1 518 018 in amended form.

II. The patent as granted comprises twelve claims, Claims 1, 8, 9, 11 and 12 reading as follows (emphasis added by the Board):

"1. A method for treating a mixture containing cellulose that has not been pulped or that has been pulped chemically or chemically and mechanically, wherein the treatment comprises at least one step of adding at least one agent capable of reducing carbonyl groups and wherein the mixture containing cellulose is an aqueous slurry of cellulose leading to cellulose ethers or cellulose esters, characterized in that the at least one agent capable of reducing carbonyl groups is added after the last stage of a multi-stage bleaching process."

"8. Specialty cellulose pulp leading to cellulose ethers or cellulose esters, obtainable by a process as described in any one of claims 1-7."

"9. Specialty cellulose pulp according to claim 8, characterized in that the viscosity or the brightness, or both, of cellulose ethers or esters obtained from said specialty cellulose pulp are increased over the viscosity or the ISO brightness, or both, obtained from a specialty cellulose pulp that has not been treated with the at least one step of adding at least one agent capable of reducing carbonyl groups."

"11. Specialty cellulose pulp leading to cellulose ethers or esters that has been obtained from chemically and mechanically pulping wood or from chemically or mechanically pulping wood, characterized in that the specialty cellulose pulp leading to the cellulose ethers or esters have a viscosity of at least 1.7 m**(3)/kg (1700 dm**(3)/kg) as measured according to the standard "SCAN-CM 15:99"."

"12. Use of cellulose ethers or esters obtained according to any one of claims 1-7 or obtainable according to any one of claims 8-10 for the production of viscose, composite materials, micro-crystalline cellulose formulations for food, cosmetics and pharmaceutical applications, technical filters, special photographic paper, as an additive during plastic molding, high-tenacity rayon yarn for tires and industrial hoses, paints, printing inks, LCD screens, high value specialty paper applications, battery separators, circuit boards and non-woven fabrics."

III. The patent was opposed in its entirety on the grounds of lack of novelty and lack of inventive step (Article 100(a) EPC) as well as of insufficiency of the disclosure (Article 100(b) EPC). The following items of evidence were inter alia relied upon:

D1: C. Chirat, Effet de l'ozone sur les hydrates de carbone et la lignine des pâtes à papier chimiques. Application au blanchiment; thesis discussed on 29 June 1994, pages 47-53 and 223;

D4: WO 01/29309 A1;

D5: US 3,017,316 A;

D9: US 3,100,732 A;

D10: US 2,494,542 A; and

D22: Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd ed., vol. 5, 1979; pages 89, 100, 118-120, 129-132 and 143-145.

IV. In the decision under appeal, the Opposition Division came to the conclusion that the subject-matter of the claims according to the then pending Main Request (consisting of Claims 1-10 and 12 as granted, with Claim 12 as granted being renumbered as Claim 11) met the requirements of the EPC. More particularly, the Opposition found the following:

a) The claimed subject-matter complied with the requirements of Article 84 and 123(2) EPC.

b) The wording "leading to cellulose ethers or cellulose esters" in Claim 1 as granted implied that corresponding process steps were to be carried out, when carrying out the claimed process, to obtain cellulose ethers or cellulose esters.

c) The invention as claimed was sufficiently disclosed.

d) The subject-matters claimed were new over documents D1 to D5. The subject-matters of Claims 8 and 11 derived their novelty from that of Claim 1.

e) Document D1 represented the closest prior art. The only feature not disclosed in D1 was the feature "leading to cellulose ethers and cellulose esters". The technical problem consisted in providing of a process leading to cellulose ethers and cellulose esters with high viscosity and improved brightness values. The solution to this problem consisted in treating the cellulose with a reducing agent, in combination with further process steps for preparing cellulose ethers/esters implied by Claim 1 as granted. This solution was not obvious over the cited prior art.

f) The subject-matter of each of Claims 8 and 11 benefited from the non-obviousness of the subject-matter according to Claim 1.

V. With its statement setting out the grounds of appeal, the Appellant (Opponent) submitted the following new items of evidence:

D26: US 5,035,772 A;

D27: M. Jackson, CTMP - its manufacture, properties and end uses; Paper Technology, July 1989, pages VII 18-25;

D28: P.M. Sharman, BCTMP growth, demand to continue Worldwide during future decades; BCTMP-Special Report, Pulp & Paper Special Report, Front Page and Pages S2-S32 (undated).

It contested the construction of Claim 1 adopted by the Opposition Division, raised two objections regarding sufficiency of the disclosure, one regarding Claim 10 (i.e. granted Claim 11) and one against Claim 1 as allowed by the Opposition Division. Moreover, it maintained that the subject-matters of independent Claims 1, 8 and 11 were not new over D1, D5, D9/D10 or D26, but that, in any case, the claimed subject-matter was obvious over D1, taken as the closest prior art, in combination with either D4 or D22.

VI. By letter dated 19 August 2013, the Respondent (Patent Proprietor) requested an extension of the time limit for replying to the Appellant's statement of grounds.

This request was refused by the Board on the ground that it was insufficiently reasoned.

VII. However, in its further letter dated 22 August 2013, the Respondent inter alia requested that the appeal be dismissed, explained the reasons for having requested an extension of said time limit and indicated that the full response to the statement would be filed as soon as possible.

VIII. This full response was filed on 26 August 2013. It comprised counter-arguments to the objections raised by of the Appellant, as well as three sets of amended claims as, respectively, its Main Request and Auxiliary Requests I and II, stated to correspond to the claim requests that had been pending before the Opposition Division.

Independent Claims 1, 8 and 10 according to said Auxiliary Request I read as follows (amendments made to Claims 1, 8 and 12 as granted made apparent by the Board):

"1. A method for the production of cellulose ethers or cellulose esters, comprising treating a mixture containing cellulose that has not been pulped or that been pulped chemically or chemically and mechanically, wherein the treatment comprises at least one step of adding at least one agent capable of reducing carbonyl groups and wherein the mixture containing cellulose is an aqueous slurry of cellulose [deleted: leading to] and providing cellulose ethers or cellulose esters from the treated mixture, characterized in that the at least one agent capable of reducing carbonyl groups is added after the last stage of a multi-stage bleaching process."

"8. [deleted: Specialty cellulose pulp leading to ][deleted: c][deleted: ]Cellulose ethers or cellulose esters, obtainable by a process as described in any one of claims 1-7."

"10[deleted: 2]. Use of cellulose ethers or esters obtained according to any one of claims 1-7 or obtainable according to any one of claims 8 or 9 for the production of viscose, composite materials, micro-crystalline cellulose formulations for food, cosmetics and pharmaceutical applications, technical filters, special photographic paper, as an additive during plastic molding, high-tenacity rayon yarn for tires and industrial hoses, paints, printing inks, LCD screens, high value specialty paper applications, battery separators, circuit boards and non-woven fabrics."

IX. In its letter dated 25 September 2013, the Appellant submitted that the Respondent's reply to the statement setting out the grounds of appeal was filed too late and should, therefore, not be admitted into the proceedings. The Appellant also submitted further arguments regarding the admissibility of D26, D27 and D28, its insufficiency objections and on novelty and inventive step. It maintained its request for revocation of the patent.

X. In a fax communication issued on 11 February 2016, the Board gave its provisional opinion on some of the salient issues of the case. More particularly, the opinion expressed was:

- positive regarding the admissibility of the Respondent's reply, including Auxiliary claims Requests I and II, into the proceedings;

- negative regarding the admissibility of the newly filed documents D26 to D28;

- negative regarding the admissibility of the sufficiency objections raised in the Appellant's statement of grounds into the proceedings;

- open to a broader construction (without implicit further method steps) of the method of Claim 1,

- questioning, on the basis of such broader construction, the issue of novelty of the subject-matters of Claims 1, 8 and 11 over D1, D5, D9/D10 and D26, if admitted, and,

- inquisitive as to the compliance of the amended claims according to the auxiliary requests with the requirements of Articles 123(2) and (3) and 84 EPC, in particular regarding compliance of Claim 1 according to Auxiliary Request I with Article 123(3) EPC.

XI. By fax dated 15 February 2016, the Respondent requested a postponement of the scheduled oral proceedings, inter alia on the ground that the communication by the Board raised new issues.

With letter of 16 February 2016, the Appellant took the position that the date of the Oral Proceedings should be maintained.

The Board, in a further communication dated 23 February 2016, informed the parties that the date of the oral proceedings would be maintained.

XII. In a letter dated 23 February 2016, the Appellant inter alia raised objections, under Articles 83, 84 and 123(2)(3) EPC, against Claims 1, 8 and 10 of Auxiliary Request I.

XIII. In its letter dated 25 February 2016 the Respondent maintained its pending Main Request and Auxiliary Request I, turned its previously pending Auxiliary Request II into Auxiliary Request IV, and submitted further fresh sets of claims as Auxiliary Requests IA, II, III, IVA, V and VI.

XIV. Oral proceedings were held on 4 March 2016. In the course of the debate, the parties were inter alia heard regarding the following issues:

- interpretation of the feature "leading to cellulose ethers or cellulose esters" comprised in Claims 1 and 8 according to the Main Request;

- novelty of the subject-matter of Claims 1 and 8 of the Main Request over D1 and D5, D22 being considered as illustrating common general knowledge;

- the admissibility into the proceedings of the Respondent's written submission dated 23 August 2013, including Auxiliary Requests I and II attached thereto, and, in particular, the admissibility of Auxiliary Request I;

as well as,

- a request of the Respondent for remittal of the case to the first instance for further prosecution, submitted in the course of the debate, once the Board had informed the Parties of its view regarding novelty of Claim 1 according to the Main Request.

XV. Final Requests at the oral proceedings

The Appellant (Opponent) requested that the decision under appeal be set aside and that the patent be revoked.

The Respondent (Patent Proprietor) requested that the appeal be dismissed (Main Request) or, in the alternative, that the case be remitted to the department of first instance for further prosecution, or that the patent be maintained on the basis of the claims according to one of Auxiliary Requests I, IA, II, III, IV, IVA, V or VI, taken in this order, all filed with letter dated 25 February 2016.

XVI. The arguments of the Appellant of relevance for the present decision can be summarised as follows:

Admissibility of the Respondent's reply to the statement of grounds of appeal

The response, including Auxiliary claim Requests I and II, was filed too late and should not, therefore, be admitted into the proceedings.

Main Request - Construction of the feature "leading to cellulose ethers or cellulose esters"

Article 84 EPC required the claims to be clear, concise and supported by the description. Said feature in Claim 1 was unclear, even taking into consideration the other claims in this respect. Claim 1 concerned a method for treating a cellulose mixture (starting material) with a reducing agent after a multistage bleaching process (method step). The feature "leading to cellulose ethers or cellulose esters" did not imply any additional steps of conversion to cellulose ethers or esters. This was apparent from the claims and from several instances in the description of the patent in suit as well. Claim 8 was actually directed to the product of the method of Claim 1, i.e. the specialty cellulose pulp, and showed the meaning of the feature in question. Claim 11 at issue had been drawn up during the examination proceedings and could not be used "a posteriori" to interpret Claim 1. According to a number of instances in the patent specification, the feature in question simply indicated in the context of Claim 1 that the cellulose mixture treated as defined in this claim was suitable for subsequent conversion to cellulose ethers or esters. Consequently, Claim 1 was to be construed as only requiring two process steps: a multistage bleaching step and, thereafter, a treatment with a reducing agent, in order to obtain, starting from any mixture containing cellulose, a specialty cellulose pulp. The latter might subsequently be converted into cellulose ethers or esters by further steps, which, however, were not mandatory for the method according to Claim 1.

A more specific meaning, if any, to be given to the "leading to ..." feature in terms of properties of the cellulose should emanate from the patent in suit itself rather than from D4 or D22. The patent in suit, e.g. Paragraphs [0019] and [0022], imposed no limitation whatsoever on the starting cellulose, which could be of any kind. Hence, the objected to feature "leading to cellulose ethers and esters" was only a desideratum merely specifying that the treated cellulose pulp could subsequently be converted to cellulose ethers and esters. It did not impart any further qualifications either to the treated pulp. Hence, there was no difference derivable from "specialty cellulose pulp", as nothing was disclosed in the patent in suit as to why it was labelled "special". Indeed, according to D22 (page 120, "Manufacture", second paragraph), even cotton linters, i.e. any cellulose pulp, might be used for preparing cellulose acetate.

Main Request - Novelty - Claims 1 and 8

The method of Claim 1 lacked novelty, inter alia over each of D1 and D5.

In particular, D1 disclosed (page 48, Point II) a chemical pulp bleached according to a conventional multistage bleaching process. Also, D1 disclosed (Table II.1 on page 52, and Point II.2.2.a on page 53) that

after a reduction step with sodium borohydride following the bleaching carbonyl groups were no longer detectable.

D5 (Example 1) disclosed the treatment of a commercial bleached spruce, a pulp as claimed, with chlorine dioxide, followed by washing, and a final treatment with sodium borohydride.

Thus, D1 and D5 both took away the novelty of the subject-matter of Claim 1.

Since the pulps of D1 and D5 were suitable for producing cellulose ethers/esters, as evidenced by D22, disclosing common general knowledge, the subject-matter of Claims 1 and 8 was not new either.

Auxiliary Request I - Allowability issues

Auxiliary Request I was not prima facie clearly allowable for various reasons. The amended claims were objectionable under Articles 123(2) and (3), 83 and 84 EPC, as pointed out in the letter of 23 February 2016. More particularly, Claim 1 of Auxiliary Request I related to a method which was different from that of Claim 1 as granted. This represented an extension of protection to subject-matter not protected by the claims as granted (Article 123(3) EPC).

Respondent's request for remittal

Already during the opposition proceedings, the Patent Proprietor could and should have prepared fall-back positions, in case its interpretation of Claim 1 as granted were not followed. This had apparently not been done. In the appeal proceedings, the Patent Proprietor then provided auxiliary claim requests, and it should be able to discuss them. The possibility of a different interpretation of Claim 1 was also apparent from the Board's communication. The proceedings should not become inefficient because of the behavior of the Patent Proprietor. According to case law, it had no right that any single claim request be examined by two instances. In particular, neither the EPC nor national law foresaw that an auxiliary request not examined by the previous instance required a remittal of the case. In the present case a remittal was indeed not justified.

XVII. The arguments of the Respondent of relevance for the present decision can be summarised as follows:

Admissibility of the response to the statement of grounds of appeal

The late filing of the response was due to special circumstances, not intended to slow down the proceedings. It was finalized and filed without any further delay upon receipt of the Board's communication by which the extension of the set time limit was refused. Thus, the response and the Auxiliary Requests I and II should be admitted into the proceedings. Moreover, Auxiliary Requests I and II had already been filed ahead of the oral proceedings before the Opposition Division (with letter dated 10 September 2012). They were not dealt with in the decision under appeal because the then pending Main Request had been allowed.

Main Request - Construction of the feature "leading to cellulose ethers or cellulose esters"

Considering Article 84 EPC, more weight had to be given to the claims than to the description when interpreting a feature of a claim for the purpose of determining its subject-matter. According to case law, a claim should be construed with a mind willing to understand, hence it should not be read illogically. In the present case, the claims were linguistically clear and made technical sense. Claim 1 concerned a method, hence its category was clear. In a method claim, each feature had to be checked on its own as to whether it concerned a step, even if the feature was an "unusual definition". The claimed method was thus to be construed as comprising three steps: treating a cellulose mixture; adding at least an agent capable of reducing carbonyl groups; and, providing for the method to lead to cellulose ethers/esters. The interpretation of "leading to ..." in Claim 1 as "suitable for ..." was not something usual in the context of a method claim. It was also apparent from Claims 8 and 9, concerning a product obtainable by the method of Claim 1, as well as from Claim 11 (Claim 12 as granted), concerning the use of the cellulose ethers/esters, taken in conjunction, that the method of Claim 1 implied further steps leading to cellulose ethers or ethers as end-products. In particular, in Claim 8, the comma had not been omitted due to an obvious error. Since the method of Claim 1 led to cellulose ethers/esters, the product of Claim 8 should be a product from the method of Claim 1, i.e. cellulose ethers/esters. Questioned by the Board why, in Claim 12 (as granted), the feature "obtainable according to any one of Claims 8 to 10" did not read "according to any one of Claims 8 to 10", the Respondent argued that, in Claim 12, the expression (emphasis added by the Board) "obtainable according to any one of Claims 8 to 10" did not make sense, as the products of Claim 12 were also "obtained according to any of the methods of Claims 1-7". Thus,

"obtainable ...", in Claim 12, implying a different kind of process, should still concern the same end-products products of the method of Claim 1, i.e. Claim 8 could only concern the ester/ether products obtained from the method of Claim 1. Thus, in view of Claims 8 and 12, Claim 1 was, without any doubt, directed to the obtention of cellulose ethers or esters as final products. The differing interpretation given by the Appellant was implausible, given that cellulose was as such suitable for the purpose of "leading to cellulose ethers or cellulose esters".

Thus, Claim 1 was clear, and there was no need to consult the description, which, in any case, should be that of the patent specification, not that of the PCT application. In case the description were consulted, the examples referring to the claimed cellulose ethers/esters, paragraphs [0015] and [0016], and Figure 1 were the clearest parts, leading the skilled person to the same conclusion as reached when construing the feature in question based on the claims only. Also paragraph [0013] supported the narrow construction of Claim 1, in the sense that the feature "leading to cellulose ethers and cellulose esters" was an intrinsic part of the method claimed. The claimed method had to lead to cellulose ethers/esters, the latter showing the technical effect of having been prepared from specialty cellulose pulp of improved viscosity and brightness. The formation of these derivatives was not an optional feature of Claim 1 .

If, for any reason, this construction were not accepted, it should then be considered that the aqueous slurry of cellulose defined in Claim 1 was further delimited by the feature "leading to cellulose ethers and esters", in the sense that it implied a certain quality for the starting cellulose. In fact, a distinction had to be drawn between "market cellulose", as disclosed in D4, page 5, and specialty cellulose for producing cellulose ethers and esters. The latter required a higher content of alpha-cellulose, 95-98%, as disclosed in D22, page 100.

Novelty - Main Request - Claims 1 and 8

The mandatory step(s) implied by the contested feature "leading to cellulose ethers and cellulose esters" could not be disregarded when examining novelty. Hence, the objections against novelty raised on the basis of combinations of e.g. any of D1 and D5 with common general knowledge concerning the preparation of cellulose ethers and esters, as illustrated by D4 or D22, did not comply with the standard disclosure test applied by the EPO. The cited prior art did not take away novelty of the process according to Claim 1, as none of D1 to D5 directly and unambiguously disclosed a process resulting in cellulose ethers or esters as final products.

More particularly, D1 was made up of only some pages of a thesis, disclosing the express steps of the claimed process, but this document was neither concerned with the purity of the treated cellulose, nor with the preparation of cellulose ethers/esters. D22 evidenced that cellulose should have high purity and high content of alpha-cellulose. D5 did not directly and unambiguously disclose a multistage bleaching according to the patent in suit. The different process of D5 thus led to a different product. Also, D5 did not disclose any use as claimed of the product obtained by its process. Thus, the claimed process and product were new over D1 and D5.

Auxiliary Request I - Allowability issues

Auxiliary Request I was also clearly allowable. The method of Claim 1 as amended was expressly and specifically directed to the preparation of cellulose ethers and esters as end-products. Such method was covered by the scope of protection afforded by granted Claims 8 and 12, which concerned cellulose ethers and esters produced from the specialty cellulose pulp.

The claims according to Auxiliary request I could not give rise to new issues, as these requests resulted from deletions of granted claims, or in order to clarify their scope. The claims were also clear.

Request for remittal

A remittal to the department of first instance was, however, appropriate in the present case. The claims according to Auxiliary Request I were on file since September 2012, and had been (re-)filed again in 2013. Until one month before oral proceedings, no objections were ever raised against product-by-process Claim 8 as granted, let alone regarding novelty. The problem was not that the Patent Proprietor was supposed to comply with formal requirements when filing amended claim requests, but that the Board's construction of the feature "leading to ... " in Claim 1 as granted was different from the one adopted by the Opposition Division. This different reading of Claim 1 implied that the claimed subject-matter to be defended was different, and that the claims of Auxiliary Request I had also to be examined for a shift of the protection conferred, which was difficult to analyse. In any case, this should be carried out by two instances to safeguard the right to appeal of the Patent Proprietor. These complicated issues could not be dealt with during oral proceedings. Basically, Auxiliary Request I, never dealt with before, not attacked until shortly before the oral proceedings, now needed to be examined for compliance with Articles 123(2),(3) and 84 EPC, taking into account the construction of the granted claims adopted by the Board.

Although a first reply to these attacks was already provided in writing, an examination of the complex issues entailed should first be carried out by the Opposition Division. Thus, in line with decision T 1300/06 of 8 April 2008, the case should be remitted to the Opposition Division for further prosecution.