T 1146/01 02-09-2004

I. The grant of European patent No. 0 492 656 in respect of European patent application No. 91 122 310.5, filed on 27. December 1991 and claiming priority of 28 December 1990 of an earlier application in Japan (418497/90), was announced on 30. July 1997 (Bulletin 1997/31). The patent contained 5 claims reading as follows:

"1. A polyethylene composition which comprises: (I) 20 to 80 wt.% of a copolymer of ethylene and Alpha-olefins having 3 to 18 carbon atoms, which copolymer meets the following conditions (a) to (d):

(a) intrinsic viscosity (Eta1 (decalin solution, 135°C)): 1.2 to 9.0 dl/g

(b) density (d1): 0.890 to 0.935 g/cm3

(c) in the elution temperature-eluate volume curve in continuously temperature rising elution fractionation, the ratio S (Ib/Ia) of the area Ib under the curve of elution temperature of 25 to 90°C to the area Ia under the curve of elution temperature of 90°C and above, is not larger than the value S1 which is calculated with the following equation,

S1= 20 Eta1-1 exp[-50(d1- 0.900)]

(d) the quantity W wt.% of the content which is soluble in 25°C o-dichlorobenzene is not smaller than the value W1 which is calculated with the following equation,

W1= 20 exp(-Eta1)

and

(II) 80 to 20 wt.% of ethylene homopolymer and/or the copolymer of ethylene and Alpha-olefins having 3 to 18 carbon atoms, which meet the following conditions (e) and (f):

(e) intrinsic viscosity (Eta2 (decalin solution, 135°C)): 0.2 to 1.6 dl/g

(f) density (d2): 0.890 to 0.980 g/cm3 wherein the value (Eta1) is larger than (Eta2), the intrinsic viscosity (Eta) of the composition is 0.77 to 5.2 dl/g, the density (d) thereof is 0.890 to 0.950. g/cm3 and the N-value calculated with the following equation is 1.7 to 3.5:

Equation

wherein "Gamma" is an apparent shear rate (sec-1 at 170°C) and "Tau" is an apparent shear stress (dyne/cm2 at 170°C) and the subscripts "20" and "150" indicates [sic] loads of 20 kg/cm2 and 150 kg/cm2.

2. The polyethylene composition as claimed in Claim 1, wherein the Alpha-olefin used for preparing said ethylene-Alpha-olefin copolymer as said component (I) is at least one member selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene and 1-decene.

3. The polyethylene composition as claimed in Claim 1, wherein said component (II) is ethylene homopolymer.

4. The polyethylene composition as claimed in Claim 1, wherein said component (II) is a copolymer of ethylene and at least an Alpha-olefin selected from the group consisting of 1-butene, 1- pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene and 1-decene.

5. The polyethylene composition as claimed in Claim 1 or 4, wherein said component(II) is a mixture of ethylene homopolymer and ethylene-Alpha-olefin copolymer."

II. On 21 and 30 April 1998, respectively, two Notices of Opposition were filed in which revocation of the patent in its entirety was requested. In the Notice of Opposition of Opponent 1, objections of lack of novelty and lack of inventive step were raised (Article 100(a) EPC, in conjunction with Articles 54 and 56 EPC). According to the Notice of Opposition of Opponent 2, the claimed subject-matter was not patentable on the grounds set out in Article 100 EPC, in particular Article 100(a) and (b) EPC, since it did not meet the requirements of Articles 54 (novelty), 56 (inventive step) and 83 EPC (insufficiency of disclosure). The following documents were amongst those referred to:

D1: EP-A-0 057 891 and

D2: "Experimental and Results of repetition of Comparative Example 30 carried out by the Opponent"

both filed by Opponent 2.

In the course of oral proceedings held before the Opposition Division on 10 April 2001, sets of claims forming a first and a second Auxiliary Request, respectively, were submitted by the Patent Proprietor.

In the first Auxiliary Request, a disclaimer, with the wording "a composition wherein component I has a density d1 of 0.928 g/cm3 and an intrinsic viscosity Eta1 of 2.2 dl/g and component II has a density d2 of 0.934. g/cm3 and an intrinsic viscosity Eta2 of 0.61. dl/g being excluded", had been inserted at the end of Claim 1.

In Claim 1 according to the second Auxiliary Request, the ranges of the intrinsic viscosities Eta1 of component I, Eta2 of component II and Eta of the final composition had been redefined as being from 3.1 to 5.9. dl/g, from 0.36 to 1.05 dl/g and from 1.58 to 3.20. dl/g, respectively. Moreover, the range of the N- value of the final composition had been narrowed to from 1.87 to 2.87.

III. In a decision orally announced at the end of the oral proceedings and issued in writing on 13 August 2001, the patent in suit was revoked.

Whilst the objection of insufficient disclosure under Article 100(b) EPC was rejected, it was held that Claims 1, 2 and 4 of the Main Request, ie of the patent in suit as granted (section I, above), lacked novelty over D1 in view of the reworking of Comparative example 30. of D1 in D2 (decision under appeal: section II.6) a) to f)). It was held that the measured values presented in D2 represented an accurate reworking of the cited passages of D1 and were, therefore, taken as they stood.

As to the first Auxiliary Request, the disclaimer in Claim 1 had not been disclosed in the application as originally filed, but had been taken from D1, which, however, did not remain "insignificant for the further examination, in particular of inventive step" as quoted from T 13/97 dated 22 November 1999. Hence, the disclaimer did not fulfil the criteria for the admissibility of a disclaimer as established in the jurisprudence, eg in decisions T 434/92 of 28 November 1995, T 596/96 of 14 December 1999 and T 13/97, above (none of which had been published in OJ EPO).

As regards the second Auxiliary Request, it was found that each of the values of intrinsic viscosity Eta1, Eta2 and Eta, which had no basis in the general description, but had been taken from the data in Examples 5 and 17 of the patent in suit, respectively, concerned properties of a specific polymer which were linked with the other parameters particular to that polymer. Thus, the intrinsic viscosity of any one example was seemingly not preselected in isolation but was obtained as a result of the polymerisation along with all of the other product characteristics. Hence, the situation was different from that dealt with in T 201/83 (OJ EPO 1984, 481), and it was, therefore, not possible to single out desired intrinsic viscosity values to establish new ranges and not be bound by the values obtained for d1, d2, d, S and W reported in the same examples. The same argument was valid for the amended range of the N-value of the final composition.

Consequently, both Auxiliary Requests were found to contravene Article 123(2) EPC.

IV. Against this decision, a Notice of Appeal was filed by the Patent Proprietor/Appellant on 19 October 2001. The prescribed fee was paid on the same date. The Statement of Grounds of Appeal was received on 20 December 2001.

In the Statement of Grounds of Appeal and in a further letter dated 8 October 2003, the Appellant disputed the reasons for the revocation as given in the decision under appeal. Moreover, new Main Requests and new auxiliary requests were filed with each of these submissions to replace the respective previous requests.

Claim 1 of the Main Request as filed with the letter dated 8 October 2003 differed from Claim 1 as granted (section I, above) by the following features added to the end of the claim:

", the composition having (g) an Izod impact strength measured according to JIS K 7110 at 23°C and -40°C of at least 6.4 kgf.cm/cm2 and (h) a tensile impact strength measured according to ASTM D 1822 with 2 mm thick test pieces of 120 to 2000 kgf.cm/cm2.".

Claim 1 of the first Auxiliary Request filed with the letter dated 8 October 2003 read as follows:

"1. A polyethylene composition which comprises: (I) 20 to 80 wt.% of a copolymer of ethylene and Alpha-olefins having 3 to 18 carbon atoms, which copolymer meets the following conditions (a) to (d):

(a) intrinsic viscosity (Eta1 (decalin solution, 135°C)): 3.1 to 5.9 dl/g

(b) density (d1): 0.900 to 0.930 g/cm3

(c) in the elution temperature-eluate volume curve in continuously temperature rising elution fractionation, the ratio S (Ib/Ia) of the area Ib under the curve of elution temperature of 25 to 90°C to the area Ia under the curve of elution temperature of 90°C and above, is not larger than the value S1 which is calculated with the following equation S1 = 20 Eta1-1 exp [-50(d1-0.900)]

(d) the quantity W wt.% of the content which is soluble in 25°C o-dichlorobenzene is not smaller than the value W1 which is calculated with the following equation W1 = 20 exp (-Eta1)

and

(II) 80 to 20 wt.% of ethylene homopolymer and/or the copolymer of ethylene and Alpha-olefins having 3 to 18 carbon atoms which meet the following conditions (e) and (f)

(e) intrinsic viscosity (Eta2 (decalin solution, 135°C)): 0.36 to 1.05 dl/g

(f) density (d2): 0.910 to 0.955 g/cm3, wherein the value (Eta1) is larger than (Eta2), the intrinsic viscosity (Eta) of the composition is 1.58 to 3.20 dl/g, the density (d) thereof is 0.905 to 0.949. g/cm3 and the N-value calculated with the following equation is 1.87 to 2.87:

Equation

wherein Gamma is an apparent shear rate (sec-1 at 170°C) and Tau is an apparent shear stress (dyne/cm2 at 170°C) and the subscripts "20" and "150" indicate loads of 20 kg/cm2 and 150 kg/cm2.".

Claim 1 of the second Auxiliary Request filed with the letter dated 8 October 2003 differed from Claim 1 as granted (section I, above) by the following disclaimer added to the end of the claim:

"With [sic] the exception of a composition having a density of 0.929, a melt index of 1.2, a MFR of 70 and an intrinsic viscosity of 1.4, comprising 50 wt.-% of an ethylene-butene-1-copolymer having a density of 0.928. and an intrinsic viscosity of 2.2 and SCB of 8 and 50 wt.-% of an ethylene-butene-1-copolymer having a density of 0.934 and an intrinsic viscosity of 0.61 and SCB of 22, wherein SCB is the molecular weight distribution index calculated by the FT-IR spectrum substration [sic] method disclosed in EP 057891 A2.".

In each of these requests, dependent Claims 2 to 5 retained their wording as granted (section I, above).

Having regard to the above disclaimer, the Appellant requested suspension of the appeal procedure until the Enlarged Board of Appeal would have rendered decisions in the cases G 1/03 and G 2/03 (which in the meantime have been published in OJ EPO 2004, 413 and 448, respectively). Since, according to OJ EPO 2004, 448, "The 'Headnote', 'Summary of facts and Submissions', 'Reasons for the decision' and 'Order' in G 2/03 are the same as in G 1/03", each reference to G 1/03 herein below should be understood as to refer to both decisions.

V. In a letter dated 31 October 2002 of Respondent 2/Opponent 2, the request for revocation of the patent in suit was maintained and the reasons given in the decision under appeal were supported.

VI. In a Communication issued on 10 December 2003, the parties were informed of the suspension of the procedure as requested by the Appellant. Furthermore, a number of provisional, preliminary remarks as to the question of allowability of the amendments in the Main and first Auxiliary Requests of the Appellant, as quoted in section IV, above, with regard to Articles 123(2) and 123(3) and 84 EPC were communicated to them.

(a) Thus, reference was made to Examples 8, 10 and 17, from which individual values of technical features had been taken to form the limits of new ranges of the additional features (g) and (h) in Claim 1 of the Main Request, and to Examples 3, 5, 10, 14, 16, 17, and 21 with regard to the new limits of the parameter ranges in Claim 1 of the first Auxiliary Request, whereby only the upper limit of density d1 had also a basis on page 4, line 13 of the general description of the patent in suit (or in the application as filed on page 8, line 8).

Furthermore, note had been taken of different positions taken, on the one hand, by Respondent 2 who had expressed the opinion that such values of individual examples could not be generalised, and, on the other hand, by the Appellant who had argued that the additional parameters in Claim 1 (Izod impact strength "IIS", and tensile impact strength "TIS") of the Main Request corresponded to those "as disclosed in all examples relevant for the present invention".

(b) A further question was raised in the communication, the question of which examples in the patent in suit complied with the definitions in Claim 1 as granted and, consequently, could, in principle, form a basis for an amendment of this claim.

Thus, in all versions of Claim 1 (as quoted or referred to in sections I and IV, above, respectively), the N-value had been defined by the formula

FORMULA

wherein the apparent shear rates Gamma in the numerator and apparent shear stresses Tau in the denominator of the fraction were the values defined for a temperature of 170°C. However, in the explanation of the method to be applied in the determination of this parameter (patent in suit: page 6, item (6)), reference was made to measurements in a flow tester at either 170°C or 210°C, dependent on the melt flow rates of the material of the samples, in order to get the necessary apparent shear rates at the required test pressures of 20 and 150 kg/cm2. Hence, the question arose of whether measurements at 210°C, as carried out in Examples 2 to 10 and 18 to 20 of the patent in suit, could form a basis for the amendment of a definition based on a value defined for 170°C.

VII. By communication dated 29 April 2004, the parties were informed that the procedure was resumed, since the Enlarged Board of Appeal had rendered decision G 1/03 (above), and they were summoned to oral proceedings.

VIII. In letters dated 12 July 2004 of Respondent 2 and 28. July 2004 of Respondent 1/Opponent 1, objections were raised with regard to the amendments in the respective requests of the Appellant.

IX. Oral proceedings were held on 2 September 2004 in the presence of all the parties. The issues dealt with in these proceedings focussed on the question of whether the Main Request and the two Auxiliary Requests, all as filed with the letter of 8 October 2003 (section IV, above), complied with Article 123(2) EPC.

The arguments presented by the Appellant in the Statement of Grounds of Appeal, the letter dated 8. October 2003 and the oral proceedings held on 2. September 2004 may be summarised as follows:

(a) As regards the Main Request, the Appellant pointed out that the limits of the ranges concerning the additional technical features (g) and (h) of Claim 1, ie IIS at 23°C and at -40°C and TIS, were taken from the examples of the patent in suit. Thus, the required minimum value of IIS, measured in accordance with the explanation on page 7, lines 5 to 12 of the patent in suit, could be found in Example 8 ("6.4", whilst a number of samples in other examples were not broken). The two limits of the TIS range were taken from Examples 17 ("120") and 10 ("2000"), respectively. The above amendments meant a limitation in comparison to Claim 1 as granted and were supported by all examples "relevant for the present invention" (Statement of Grounds of Appeal, page 2, line 11), ie "which belonged to the present invention" and "are considered to be the core of an invention and ... generally support the preferred lower values and upper values of a parameter range" (letter dated 8 October 2003, page 3, lines 13 to 24). As these examples disclosed preferred embodiments of the claimed subject-matter, the Main Request complied with Article 123(2) EPC.

On the question in the first Communication concerning the determination of the N-value (section VI(b), above), the Appellant commented only at the oral proceedings and, on this occasion, expressed the opinion that the difference in the temperature of the measurement, ie at 170°C or 210°C, would not significantly affect the result of the such a determination.

(b) As regards the first Auxiliary Request, wherein the ranges of technical features in Claim 1 had been amended on the basis of measured values disclosed in different examples of the patent in suit, the Appellant referred to its arguments previously presented with regard to the Main Request.

(c) In the context of the second Auxiliary Request, the Appellant had pointed out in its letter dated 8 October 2003, paragraphs bridging pages 2/3, that

"1. The disclosure of D1 is an accidental, novelty- destroying disclosure, since it relates to a comparative example of a cited document[s]. Only by reworking the single comparative example the Opponent produced a polymer composition meeting the parameters of the opposed patent.

2. Although D1 is prior art under Art. 54(2), it is not relevant for the determination of the inventive step. D1, by showing that comparative example 30 results in a composition which does not solve the problem underlying D1 (and which evidently does not solve any problem) suggests to the skilled person not to use a composition such as that of comparative example 30 and consequently teaches away from the essential features of the present invention.".

Complementary to these arguments, the Appellant further argued at the oral proceedings that, although the technical fields of D1 and of the patent in suit were the same and, moreover, the aims to be achieved by them were in common, Comparative example 30 of D1 could be disclaimed, because the solution of the patent in suit was pointing in a direction which, according to the comparative example, was not to be followed.

Therefore, even though D1 had been considered by the Opposition Division as the closest state of the art, Comparative Example 30 did not belong to the invention of that document, since it neither fulfilled certain features of D1, nor achieved the advantages of that invention, nor formed part of that invention.

Consequently, the requirements for the allowability of a disclaimer as defined in decision G 1/03 (above) had been met by the disclaimer in question, for which the Appellant saw two justifications: (i) it was necessary in order to exclude the anticipatory disclosure of Comparative example 30 of D1, and (ii) this anticipation was accidental, as eg defined in T 1071/97 of 17 August 2000 (not published in OJ EPO; referred to in point 2.2.2 of the reasons of G 1/03) which said in 3.2 of the reasons: "what is disclosed in the prior document could accidentally fall within the wording of the claim(s) of the application or patent to be assessed for novelty without there being a common or related technical field, or a common technical problem or solution".

On this basis, it would have neither been decisive whether or not the technical field of D1 was remote from that of the patent in suit, nor whether both of these documents dealt with a common technical problem, but that it was sufficient that there was no common solution.

The arguments presented by the Respondents in their letters of 12 July 2004 and 28 July 2004, respectively, and in the oral proceedings held on 2 September 2004 may be summarised as follows:

(d) As regards Claim 1 of the Main Request, the additional technical features (g) and (h) and their ranges, eg "6.4" taken from Example 8, were arbitrary selections taken from a minimum of three separate, non-linked examples. Furthermore, this value of "6.4" had only been disclosed for an IIS at - 40°C, but not for +23°C.

Moreover, the individual values used to define the new ranges of features (g) and (h) had been disclosed in conjunction with all the other parameters present in each example and could not, therefore, be treated as discrete disclosures. Figures 4 to 8 in the patent in suit showed the interrelations between these properties with other properties of the polymers. The IIS and TIS values of any one example were dependent on polymerisation conditions as well as all of the other product parameters. Therefore, it was not possible to single out these values and not be bound by the values of S, W etc. reported in the same examples.

Furthermore, it was disputed that Examples 11 to 13. and 22 were no longer "appropriate examples of the invention" as they had been when the original application had been filed. According to the patent in suit, the claimed compositions had excellent mechanical properties, especially at low temperature, good fluidity, wide molecular weight distribution and excellent melt elasticity. It was not understood why "6.4" was to be considered a good IIS, whilst "4.2" (Example 22) was not, or why "120" represented an acceptable TIS whereas "100" (as in Example 13) did not. Moreover, Examples 11 to 13 and 22 showed a number of further good, sometimes even better properties than the preferred examples. Thus, reference was made to yield tensile strength "YTS", flexural (Olsen) strength "OS" and environmental stress cracking resistance "ESCR" (cf. letter dated 31. October 2002, items 5 to 8, 11, 13, 14 to 18; all quoted IIS and TIS values should be understood in terms of "kgf·cm/cm2"). These facts demonstrated that the selections made by the Appellant were arbitrary.

Moreover, whilst the data of the N-values were defined in Claim 1 for a temperature of 170°C, the measurements of the apparent shear rates Tau, necessary for the determination of these values, had, however, been carried out in a number of examples including Example 8 at 210°C. Since measurements of a physical property obtained in certain conditions, eg at a specific temperature, could not be translated into numerical values of this property valid for different conditions without providing a clearly understandable calculation method or at least a calibration for a translation, no one even knew whether these examples had complied with the requirements in Claim 1 as granted. Therefore, none of them, including Example 8 used to define feature (g), could form a basis for any amendment of the claims (letters of the Respondents, dated 12 July 2004: the paragraph bridging pages 1 and 2, and 28 July 2004: page 2, last paragraph, respectively, and statements at the oral proceedings, left uncommented by the Appellant).

In summary, the definition of new range limits by generalisation of selected measured values from individual examples contravened Article 123(2) EPC.

(e) As regards the first Auxiliary Request, the Respondents referred to their arguments previously presented with regard to the Main Request.

(f) Concerning the second Auxiliary Request, the Respondents argued that D1 as a whole was not remote from the claimed subject-matter, which could even be seen from the search report, wherein D1 had been identified as a D,X-document. Nor was its disclosure irrelevant for any further examination of the claimed invention. Moreover, Comparative example 30 was only comparative, because it did not fulfil the ratio of the short chain branching parameters of its two polymer components, which, however, was not relevant to the present question. Component A of that comparative example complied with all the requirements of the high molecular weight component I according to Claim 1 of the patent in suit. In any case, Comparative example 30 was part of the disclosure of D1, which on its page 12 referred to the same properties as aimed at in the patent in suit: ESCR, impact strength, thermal resistance. The inventor, when working on his invention would have taken into account all the examples of D1, including Comparative example 30, which was, in any case, also a disclosure in itself.

X. The Appellant requested that the decision under appeal be set aside and that the patent be maintained on the basis of Claims 1 to 5 according to the Main Request as submitted with the letter dated 8 October 2003 or, in the alternative, on the basis of Claims 1 to 5 of the first Auxiliary Request or of the second Auxiliary Request as submitted with the same letter, respectively.

The Respondents requested that the appeal be dismissed.