T 0045/03 19-01-2005

Summary of Facts and Submissions

I. The grant of the European patent No. 0 792 890 in the name of Rohm and Haas Company in respect of European patent application No. 97 301 238.8 filed on 25. February 1997 and claiming priority of the US patent application No. 12644 filed on 1 March 1996 was announced on 29 December 1999 (Bulletin 1999/52) on the basis of 15 claims.

Independent Claim 1 read as follows:

"1. A process for preparing phosphonate-terminated polymers having a weight average molecular weight of less than 20,000, comprising polymerizing monomers selected from one or more of unsaturated carboxylic acid monomers, unsaturated "non-carboxylic" acid monomers and unsaturated acid-free monomers, in the presence of (a) water, (b) one or more water-soluble initiators and (c) phosphorous acid or a salt thereof; wherein the unsaturated carboxylic acid monomers comprise unsaturated monocarboxylic acid monomers and/or unsaturated dicarboxylic acid monomers; wherein from 75 to 100 percent by weight of the unsaturated monocarboxylic acid monomers are metered into a polymerization reactor containing water and from 25 to 100 percent by weight of the phosphorous acid or salts thereof; wherein an alkaline neutralizer is present during the polymerization to neutralize at least 30 percent, based on equivalents, of the acid groups of the unsaturated carboxylic acid monomers present; and wherein an in-process solids level is from 40 to 70 percent, based on the weight of solid reactants relative to the combined weight of solid reactants and water at the end of the polymerization."

Claims 2 to 15 were dependent claims.

II. Two Notices of Opposition were filed against the patent, as follows:

(i) by Great Lakes Chemical (Europe) GmbH, on 28. September 2000, on the grounds of lack of novelty and lack of inventive step (Article 100(a) EPC), and

(ii) by BASF Aktiengesellschaft (Opponent II), on 29. September 2000, on the grounds of lack of novelty and lack of inventive step (Article 100(a) EPC).

After expiry of the opposition period, an objection of extension of subject-matter (Article 100(c) EPC) was raised by Opponent I in its letter dated 18 July 2002.

The objections were supported inter alia by the following documents:

D1: EP-A-0 491 391;

D2: US-A-5 294 686;

D3: US-A-5 077 361;

D4: US-A-4 621 127; and

D6: EP-A-0 510 831.

III. By a decision announced orally on 18 September 2002, and issued in writing on 21 October 2002, the Opposition Division held that the grounds of opposition did not prejudice the maintenance of the patent in amended form.

The decision was based on the following requests of the Patent Proprietor:

(i) A main request consisting of the set of Claims 1 to 15. as granted,

(ii) An auxiliary request consisting of Claims 1 to 2, as submitted at the oral proceedings of 18 September 2002, and of Claims 3 to 15 as granted.

Claim 1 of the auxiliary request read as follows:

"A process for preparing phosphonate-terminated polymers having a weight average molecular weight of less than 20,000, comprising polymerizing monomers selected from one or more of unsaturated carboxylic acid monomers, unsaturated "non-carboxylic" acid monomers and unsaturated acid-free monomers, in the presence of (a) water, (b) one or more water-soluble initiators and (c) phosphorous acid or a salt thereof; wherein the unsaturated carboxylic acid monomers comprise unsaturated monocarboxylic acid monomers and/or unsaturated dicarboxylic acid monomers; wherein from 75 to 100 percent by weight of the unsaturated acid monomers or salts thereof and the one or more water-soluble initiators are metered into a polymerization reactor containing water and from 25 to 100 percent by weight of the phosphorous acid or salts thereof; wherein an alkaline neutralizer is present during the polymerization to neutralize at least 30 percent, based on equivalents, of the acid groups of the unsaturated carboxylic acid monomers present; and wherein an in-process solids level is from 40 to 70 percent, based on the weight of solid reactants relative to the combined weight of solid reactants and water at the end of the polymerization."

The decision stated that granted Claim 1 met the requirements of Article 123(2) EPC but that the subject-matter of granted Claims 1 to 15 was not novel over Example 21 of document D1.

The decision held that Claim 1 of the auxiliary request met the requirements of Article 123(2) EPC. It further stated that the subject-matter of the auxiliary request was novel over Examples 3 and 21 of D1, and over documents D2 and D4.

Concerning inventive step, the decision stated that, when starting from D1 as the closest state of the art, the technical problem was to maximise the yield of phosphonate-terminated polymers by improving the efficiency of the incorporation of phosphorous acid or salt thereof. This problem was solved by the use of an in-process neutralisation. Document D1 provided no hint to a neutralisation step.

The decision further held that when starting from D2 as closest prior art, the technical problem was also to improve the yield of phosphonate-terminated polymers. D2, however, used hypophosphorous acid or salts thereof.

According to the decision, there was no hint in D2 alone or in combination with D1 to lead one of using phosphorous acid or its salt.

Thus, the Opposition Division came to the conclusion that the subject-matter of the auxiliary request met the requirements of Article 56 EPC.

IV. A Notice of Appeal was filed on the 27 December 2002 by Opponent I with simultaneous payment of the prescribed fee.

In the Statement of Grounds of Appeal submitted on 28. February 2003, the Appellant argued essentially as follows:

(i) Article 100(c) EPC:

(i.1) The term "and/or" in Claim 1 was not supported by the application documents.

(i.2) Neither lines 25 to 26 and 57 to 58 on page 3 nor Table 4 of the patent specification could provide a support for that term.

(i.3) This amendment was therefore inadmissible.

(ii) Article 123(3) EPC:

(ii.1) According to granted Claim 1, 75 to 100% by weight of the unsaturated monocarboxylic acid monomer should be metered into the polymerization reactor.

(ii.2) Claim 1 of the auxiliary request, however, required that 75 to 100% by weight of unsaturated acid monomers be metered into the polymerization reactor.

(ii.3) This implied that Claim 1 of the auxiliary request no longer required that 75 to 100% by weight of unsaturated monocarboxylic acid monomer be added into the reactor.

(ii.4) Thus, Claim 1 of the auxiliary request contravened Article 123(3) EPC.

(iii) Interpretation of Claim 1:

(iii.1) According to Claim 1 unsaturated non-carboxylic acid and unsaturated acid-free monomers could be polymerized alone.

(iii.2) Thus, the neutralization step would be superfluous.

(iii.3) In Example 11 a salt of an unsaturated non- carboxylic acid was used. Thus, the monomer could not be neutralized.

(iii.4) Example 9 further showed that the process was carried out without neutralization.

(iii.5) Furthermore, according to the description (page 5, lines 8 to 25) the monomers could be neutralized before polymerization. There would be no in-process neutralization.

(iii.6) No indication was given for how long the metering should take place. Thus, claim 1 encompassed a process wherein all unsaturated acid monomers were added at the same time. This feature would not be suitable for establishing novelty over Example 21 of D1.

(iv) Novelty:

(iv.1) According to Example 21 of D1 the unsaturated acid was neutralized before polymerization. Thus, no in-process neutralization would be necessary.

(iv.2) Example 21 worked with an in-solid level of 63.1% and led to a polymer having a molecular weight lower than 20 000.

(iv.3) It was further clear from D1 (cf. page 6, lines 45 to 46; Example 1) that the unsaturated acid could be added to the phosphite.

(iv.4) Thus, the subject-matter of the patent in suit was anticipated in a novelty destroying manner.

(iv.5) Working Example 1 of D4 was also was novelty destroying for the subject-matter of Claim 1.

(v) Inventive step:

(v.1) According to Example 6 of D1, 82% of the phosphorous acid had reacted. The results from the patent in suit were between 15% (Example 1) and 72% (Example 7).

(v.2) Thus, starting from D1 the technical problem could not be seen in the improvement of phosphorous acid incorporation in the polymer.

(v.3) Taking further into account that Claim 1 was very broad in scope, the claimed process constituted an alternative process that the person skilled in the art would apply without inventive activity.

V. With its letter dated 22 September 2003, the Respondent (Patent Proprietor) submitted the following document:

D9: Hawley's Condensed Chemical Dictionary, 1997, page 900.

It also argued essentially as follows:

(i) Concerning Article 100(c) EPC:

The term "and/or" was supported, as stated in the decision of the Opposition Division, by lines 25 to 26, and the two last lines of page 3 of the patent in suit.

(ii) Article 123(3) EPC:

The term "wherein 75 to 100% by weight unsaturated acid monomers or salts thereof and the one or more water soluble initiators are metered into a polymerization reactor containing water and from 25 to 100% by weight of phosphorous acid or salts thereof" did not contravene Article 123(3) EPC since it was supported by lines 15 to 16 of page 6 of the published application.

(iii) Interpretation of the claims:

(iii.1) It was evident that, if the monomers were previously neutralized it was not necessary to neutralize them further, provided the reaction conditions were such to maintain the level of neutralization.

(iii.2) The skilled person would not interpret the term "metering" as meaning a process wherein all the unsaturated monomers were added at the same time to all the phosphorous acid.

(iv) Novelty:

(iv.1) It was known that polymers were macromolecules formed from 5 or more identical units called monomers (cf. D9).

(iv.2) D1 was directed to the manufacture of phosphonated compounds and oligomers.

(iv.3) Thus, Example 21 could not destroy the novelty of Claim 1.

(iv.4) Example 1 of D4 employed a thioglycolic acid chain transfer agent. This would preclude the formation of phosphonate terminated polymers.

(v) Inventive step:

(v.1) From the combination of D1 with D4 or of D1 with D2, there was no suggestion that the process according to Claim 1 would lead to an improved utilization of phosphorous acid.

(v.2) Thus, the claimed subject-matter involved an inventive step.

VI. With its letter dated 27 December 2004, the Appellant submitted a new document:

D10: C.A. Hampel et al "Glossary of Chemical Terms"; 1976; Van Nostrand Reinhold Company.

It also argued essentially as follows:

(i) Oligomers represented low molecular weight polymers (cf. D10).

(ii) Furthermore, several examples of D1 (e.g. Example 3 and 17) related to polymers.

(iii) It had been established by the Appellant that the process step disclosed in D1 (Example 21) were covered by the granted claims.

(iv) Thus the onus was on the Respondent to show that no phosphonated polymer was formed by the process of D1.

VII. With its letter dated 12 January 2005, the Respondent submitted the following document:

D11: Declaration by Mrs Josephine Eldredge, dated 11. January 2005;

as well as three sets of claims referred to as auxiliary requests I, II and III.

Claim 1 of auxiliary request I read as follows

"A process for preparing phosphonate-terminated polymers having a weight average molecular weight of less than 20,000, comprising polymerizing monomers selected from one or more of unsaturated carboxylic acid monomers, unsaturated "non-carboxylic" acid monomers and unsaturated acid-free monomers, in the presence of (a) water, (b) one or more water-soluble initiators and (c) phosphorous acid or a salt thereof; wherein the unsaturated carboxylic acid monomers are selected from one or more of unsaturated monocarboxylic acid monomers and unsaturated dicarboxylic acid monomers; wherein from 75 to 100 percent by weight of the unsaturated acid monomers or salts thereof and the one or more water-soluble initiators are metered into a polymerization reactor containing water and from 25 to 100 percent by weight of the phosphorous acid or salts thereof; wherein an alkaline neutralizer is present during the polymerization to neutralize at least 30 percent, based on equivalents, of the acid groups of the unsaturated carboxylic acid monomers present; and wherein an in-process solids level is from 40 to 70 percent, based on the weight of solid reactants relative to the combined weight of solid reactants and water at the end of the polymerization."

Claim 1 of auxiliary request II read as follows:

"A process for preparing phosphonate-terminated polymers having a weight average molecular weight of less than 20,000, comprising polymerizing monomers selected from one or more of unsaturated carboxylic acid monomers, unsaturated "non-carboxylic" acid monomers and unsaturated acid-free monomers, in the presence of (a) water, (b) one or more water-soluble initiators and (c) phosphorous acid or a salt thereof; wherein the unsaturated carboxylic acid monomers are selected from one or more of unsaturated monocarboxylic acid monomers and unsaturated dicarboxylic acid monomers; wherein from 75 to 100 percent by weight of the unsaturated acid monomers or salts thereof and the one or more water-soluble initiators are metered over a period of time ranging from 5 minutes to 5 hours into a polymerization reactor containing water and from 25 to 100 percent by weight of the phosphorous acid or salts thereof; wherein an alkaline neutralizer is present during the polymerization to neutralize at least 30 percent, based on equivalents, of the acid groups of the unsaturated carboxylic acid monomers present; and wherein an in-process solids level is from 40 to 70 percent, based on the weight of solid reactants relative to the combined weight of solid reactants and water at the end of the polymerization."

Dependent claims 2 to 15 of both auxiliary requests I and II corresponded to granted Claims 2 to 15.

Claim 1 of auxiliary request III read as follows:

"A process for preparing phosphonate-terminated polymers having a weight average molecular weight of less than 20,000, comprising polymerizing monomers selected from one or more of unsaturated carboxylic acid monomers, unsaturated "non-carboxylic" acid monomers and unsaturated acid-free monomers, in the presence of (a) water, (b) from 1 to 15% by wt based on total monomer wt of one or more water-soluble initiators and (c) phosphorous acid or a salt thereof; wherein the unsaturated carboxylic acid monomers are selected from one or more of unsaturated monocarboxylic acid monomers and unsaturated dicarboxylic acid monomers; wherein from 75 to 100 percent by weight of the unsaturated acid monomers or salts thereof and the one or more water-soluble initiators are metered into a polymerization reactor containing water and from 25 to 100 percent by weight of the phosphorous acid or salts thereof; wherein an alkaline neutralizer is present during the polymerization to neutralize at least 30 percent, based on equivalents, of the acid groups of the unsaturated carboxylic acid monomers present; and wherein an in-process solids level is from 40 to 70 percent, based on the weight of solid reactants relative to the combined weight of solid reactants and water at the end of the polymerization."

Dependent Claims 2 to 5, and 6 to 14 corresponded to granted Claims 2 to 5, and 7 to 15, respectively.

The Respondent argued essentially as follows:

(i) Document D11 showed that Example 21 of D1 did not produce phosphonate terminated polymers. Furthermore in Example 21, maleic acid was not metered into the polymerization reactor comprising 25 to 100 % by weight of the phosphorous acid.

(ii) Examples 3 and 17 of D1 would not lead to phosphonated polymers but to unphosphonated oligomers.

(iii) Auxiliary request I was based on page 6, lines 15 to 16 and claims 9 to 10 of the published application.

(iv) Auxiliary request II was based on page 6, lines 15 to 16, and line 20 and claims 9 to 10 of the published application.

VIII. With its letter dated 18 January 2005, the Appellant submitted the following document:

D12: Declaration by Mr David Wilson, dated 18 January 2005.

IX. With its letter dated 18 January 2005, Opponent II informed the Board that it would not be represented at the oral proceedings scheduled to take place on 19. January 2005.

X. Oral proceedings were held on 19 January 2005, in the absence of Opponent II.

(i) At the oral proceedings the discussion was firstly essentially focussed on the allowability of the amended set of claims, on which the Opposition Division had decided to maintain the patent in suit, under Article 123(2) and 123(3) EPC.

In that respect, both Parties, while essentially relying on their arguments presented during the written procedure, they made further submissions which could be summarized as follows:

(i) By the Respondent:

(i.1) The wording "and/or" was supported by original Claims 9 to 10, and 14 to 15.

(i.2) In view of the apparent incompatibility between original Claim 1 and these claims, the skilled person would have referred to the original description.

(i.3) In view of page 3, lines 22-23, 24-25 and 54-55, and Examples 1 to 8 of the application as published it was implicit that the unsaturated carboxylic monomer could be a monocarboxylic acid or a dicarboxylic acid.

(ii) By the Appellant:

(ii.1) Contrary to the submissions of the Respondent there was no contradiction between original Claim 1 and Claims 9 to 10, and 14 to 15.

(ii.2) There was no support in the application as originally filed for the use of an unsaturated dicarboxylic acid alone, and the feature that an unsaturated dicarboxylic acid alone could be metered to the polymerization vessel containing the phosphorus acid. In the examples in which an unsaturated dicarboxylic acid had been used, this was in combination with an unsaturated monocarboxylic acid.

Following preliminary observations from the Board concerning the allowability under Articles 123(2) and 123(3) EPC of this set of claims, the Respondent indicated its intention to submit a further auxiliary request.

After an interruption of the proceedings, the Respondent submitted a new auxiliary request referred to as "first" auxiliary request, whose Claim 1 read as follows:

"A process for preparing phosphonate-terminated polymers having a weight average molecular weight of less than 20,000, comprising polymerizing monomers selected from one or more of unsaturated carboxylic acid monomers, unsaturated "non-carboxylic" acid monomers and unsaturated acid-free monomers, in the presence of (a) water, (b) one or more water-soluble initiators and (c) phosphorous acid or a salt thereof; wherein the unsaturated carboxylic acid monomers is selected from one or more of acrylic acid, methacrylic acid, crotonic acid, vinylacetic acid, maleic acid, maleic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5- norbornene-2,3-dicarboxylic anhydride, bicyclo[2.2.2]- 5-octene-2,3-dicarboxylic anhydride, 3-methyl-1,2,6- tetrahydrophthalic anhydride, 2-methyl-1,3,6- tetrahydrophthalic anhydride, itaconic acid, fumaric acid, mesaconic acid, citraconic acid and alkali metal and ammonium salts thereof; wherein from 75 to 100 percent by wt of the unsaturated acid monomers or salts thereof and the one or more water-soluble initiators, including, if any, 75 to 100 percent by weight of the unsaturated monocarboxylic acid monomers and water- soluble salts thereof, are metered into a polymerization reactor containing water and from 25 to 100 percent by weight of the phosphorous acid or salts thereof; wherein an alkaline neutralizer is present during the polymerization to neutralize at least 30 percent, based on equivalents, of the acid groups of the unsaturated carboxylic acid monomers present; and wherein an in-process solids level is from 40 to 70 percent, based on the weight of solid reactants relative to the combined weight of solid reactants and water at the end of the polymerization."

The discussion was then essentially concentrated on the admissibility of the auxiliary requests. The arguments presented by the Parties in that respect may be summarized as follows:

(a) By the Appellant:

(a.1) The auxiliary requests I to III, and the "first" auxiliary request had been submitted at a very late stage.

(a.2) No justification had been given by the Respondent for their very late filing.

(a.3) The arguments concerning the objections under Article 123(2) and 123(3) EPC against the set of claims allowed by the Opposition Division had been submitted and detailed at the beginning of the appeal proceedings.

(a.4) These requests were at first glance not clearly allowable. They all contained the possibility for an unsaturated dicarboxylic acid to be metered alone to the polymerization vessel.

(a.5) Thus, they should not be admitted into the proceedings.

(b) By the Respondent:

(b.1) The Opposition Division had considered that the set of claims met the requirements of Article 123 EPC. The incorporation of the wording "and/or" had been accepted by the Examining Division. Its allowability had been confirmed by the Opposition Division.

(b.2) No communication had been issued by the Board on that respect before the oral proceedings.

(b.3) The Respondent had been surprised by the considerations raised by the Board under Article 123 EPC.

(b.4) Thus, although the "first" auxiliary request had been submitted at a very late stage, it should be admitted into the proceedings.

(b.5) Furthermore, it was clear that the wording "and/or" was supported by the original application documents, so that the use of an unsaturated dicarboxylic acid alone was part of the original disclosure.

XI. The Appellant requested that the decision under appeal be set aside and the patent be revoked.

The Respondent requested that the appeal be dismissed or, in the alternative that the decision under appeal is set aside and the patent be maintained on the basis of the first auxiliary request filed during the oral proceedings (consisting of cl. 1 as presented during the oral proceedings and cl. 2 to 15 as granted) or on the basis of one of auxiliary requests I to III filed with letter dated 12 January 2005.

Opponent II made no request.