T 59/08 – More On Sufficiency

This is a revocation appeal.

The independent claims on file read:

1. A multimodal polyethylene composition for pipes, which multimodal polyethylene has a density of 0.930-0.965 g/cm³ and an MFR5 of 0.2-1.2 g/10 min, characterised in that the multimodal polyethylene has an M_n of 8000-15000, an M_w of 180-330 x 10³, and an M_w/M_n of 20-35, said multimodal polyethylene comprising a low molecular weight (LMW) ethylene homopolymer fraction and a high molecular weight (HMW) ethylene copolymer fraction, said HMW fraction having a lower molecular weight limit of 3500, and a weight ratio of the LMW fraction to the HMW fraction of (35-55) : (65-45).

12. A pipe characterised in that it is a pressure pipe comprising the multimodal polymer composition according to any one of the preceding claims, which pipe withstands a pressure of 8.0 MPa gauge during 50 years at 20°C (MRS8.0).

[2] The question to be answered when assessing sufficiency of disclosure is whether the invention as defined in the claims can be performed by a person skilled in the art throughout the whole area(s) claimed without undue burden, taking into account the information given in the patent in suit and using common general knowledge.

[2.1] The invention of which the sufficiency of disclosure has to be judged is the object defined in present claim 1 by the combination of the following features:

(i) a multimodal polyethylene composition suitable for pipes,

the multimodal polyethylene having

(ii) a density of 0.930-0.965 g/cm³,

(iii) a MFR5 of 0.2-1.2 g/10 min,

(iv) a M_n of 8000-15000, a M_w of 180?330 x 10³ and a M_w/M_n of 20-35,

and comprising

(v) a low molecular weight (LMW) ethylene homopolymer fraction and a high molecular weight (HMW) ethylene copolymer fraction in a weight ratio of the LMW fraction to the HMW fraction of (35-55) : (65-45)

(vi) said HMW ethylene copolymer fraction having a lower molecular weight limit of 3500.

[2.2] The contested decision nor the parties on appeal addressed the question whether the present patent specification disclosed a technical concept fit for generalisation and whether it made available to the skilled person, with his common general knowledge, compositions suitable for pipes meeting the combination of parameters defined in claim 1, as well as the pipes according to claim 12. The questions addressed were rather which meaning should be attributed to the feature “lower limit of the high molecular weight (HMW) ethylene copolymer fraction” and whether, in the absence of any mention in the patent with respect to the measurement methods for determining M_n, M_w and the lower limit of the high molecular weight (HMW) ethylene copolymer fraction, the skilled person would know which measurement method was to be employed.

[2.3] Following the normal rule of claim construction according to which terms used in a claim should be given their ordinary meaning in the context of the claim in which they appear, the lower molecular weight limit of the HMW ethylene copolymer fraction defined in claim 1 designates the lowest molecular weight of any of the molecules of the HMW fraction. This view is supported by the statement provided in the specification on page 3, lines 9-12 and was not disputed any longer during the oral proceedings.

[2.4] In the absence in the claim of any indication of a method for determining M_n, M_w and the lower limit of the high molecular weight (HMW) ethylene copolymer fraction, the claim has to be read as allowing any method of measurement, including any setting, that can be said to be standard in the art concerned; in other words, any ordinary method within the context of the present claim. In this respect, the parties do not dispute that different methods (for example GPC), including different settings, would be available to determine values for those parameters, nor that the choice of the measurement method for determining said parameters has an influence on the values obtained.

[2.5] The notions of “true value” and closeness to that “true value” in relation to M_w and M_n parameters, to which the [patent proprietor] referred, are however not only vague, but also not reflected by the information provided in the patent in suit.

If a patent proprietor wishes to argue that a parameter range in a claim should be read in a special way or needs to be measured in a particular manner because several possibilities are available, then for that argument to be accepted it is necessary to limit the claim to this method of measurement by way of amendment, provided that this can be done meeting the requirements of A 123(2). It is not enough to argue that the claim should be read in a particular way when the wording of the claim does not require this.

For lack of information to that effect, it is not apparent that the skilled person would try to determine the “true value” of M_w and M_n, as it is at least equally credible that he would choose any standard method meeting his needs in the context of the technical circumstances of the case, i.e. also taking into account the convenience and reproducibility of that method.

[2.6] Therefore, the present claims should be read as to encompass any composition or pipe that meets the defined values of M_w, M_n and “lower limit of the high molecular weight (HMW) ethylene copolymer fraction” using any method that can be considered to be standard in the art in the technical context of the present claims as the method of measurement for those parameters.

[2.7] Such a reading of the claim may on the one hand result in a larger number of compositions or pipes meeting the claimed values than when one specific method were used, and therefore in less difficulty to obtain compositions or pipes as defined by the claims, i.e. in less stringent requirements for assessing sufficiency of disclosure of the claimed combination of features. In that case it may on the other hand require stronger arguments in favour of novelty and inventive step, in particular if the claimed values were held to distinguish the claimed subject-matter from the prior art and to be considered essential for providing a technical effect vis-à-vis the prior art.

[3] The [opponents’] argument that the conventional methods for determining M_w and M_n led to different values out of which a lack of guidance resulted for the skilled person wishing to obtain the result defined in the patent specification […], namely to obtain a pressure pipe with a desired combination of good processability and good strength, cannot be accepted as an argument pertaining to sufficiency of disclosure of the invention, as those results or effects are not features of the present claims. This follows from the consideration that - in accordance with R 43(1) – the invention in the European patent application is defined by the subject-matter of a claim, i.e. the specific combination of features present in the claim, as is reminded in opinion G 2/98 [2] of the Enlarged Board of Appeal. Whether the result defined in the present patent specification […], is achieved or not, may, however, become relevant under the requirement of inventive step, for assessing the technical problem which can be held to be successfully solved by the combination of features claimed.

[4] The uncertainty about which method the skilled person would select to determine M_n, M_w and the lower limit of the high molecular weight (HMW) ethylene copolymer fraction, which was the central issue addressed by the parties both in opposition and in appeal proceedings, is in the present case not adequate to make a case against sufficiency of disclosure.

The argument that the choice of the measurement method for determining M_n, M_w and the lower limit of the high molecular weight (HMW) ethylene copolymer fraction had an influence on the values obtained and that therefore the skilled person would not know whether he had obtained something falling within the ambit of the claims – as it was argued by the [opponents] as well as in the decision under appeal – boils down to the argument that the boundaries of the claims are not clearly defined, which is a matter of A 84, not sufficiency of disclosure. Such an objection under A 84 cannot be successful as it would not arise out of any amendment made in opposition or appeal proceedings.

[5] For assessing the requirement for sufficiency of disclosure the question should be answered whether the skilled person, following the teaching provided in the patent specification […], and also taking into account his general knowledge, would be able to obtain without undue burden multimodal polyethylene compositions meeting all criteria defined in claim 1 of the patent in suit […] and the pipe according to claim 12.

[5.1] In this respect, points raised before the opposition division […], which in particular relate to the process conditions that are needed to obtain the combination of technical features defined in the claims, and which appear to be essential to assess the sufficiency of the disclosure, should also be considered.

[5.2] However, none of those issues was decided by Opposition Division, nor argued by the parties before the Board.

[6] Under those circumstances, as the essential issues to be addressed in respect of sufficiency of disclosure have not been dealt with in the contested decision, the Board exercises its discretion under A 111(1) to remit the case to the first instance for further prosecution.

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