T 0137/01 15-12-2003

I. The appeal is from the decision of the Opposition Division posted on 30 October 2000 to reject the oppositions filed against European patent No. 0 532 002, granted in respect of European patent application No. 92115510.7.

In the decision under appeal the Opposition Division considered that the scope of claim 1 was restricted to superabsorbent particles having a size of between 300 and 600 microns or superabsorbent fibres and concluded that the skilled person could carry out the invention on the basis of specific disclosures of the patent in suit in this respect.

Furthermore, the Opposition Division held that the claimed subject-matter was novel and involved an inventive step.

II. The appellants (opponents I to IV) lodged appeals against this decision. The appeals were received at the EPO on 20, 22, 20. and 28 December 2000 respectively. The appeal fees were paid on 27, 22, 20 and 28 December 2000 respectively. The statements setting out the grounds of appeal were received at the EPO on 27, 15, 28 and 26 February 2001 respectively.

III. In an annex to the summons for oral proceedings pursuant to Article 11(2) Rules of Procedure of the boards of appeal the Board expressed its preliminary opinion that particles having a size below 300 or above 600 µm were excluded from the disclosed test procedure for determining the values of the parameters "Deformation under Load" (DUL) and "Wicking Index" (WI) and that the requirement of sufficiency of disclosure was linked to the question of whether claim 1 excluded a superabsorbent material with particles of a size outside the range of 300 to 600 µm. Furthermore, the Board stated that it would appear that the test results filed by the appellants in respect of the superabsorbent materials used in the absorbent composite referred to in document

D2: DE-C-4 020 780

supported the conclusion that the subject-matter of claim 1 lacked novetly.

IV. In response to the Board's preliminary opinion, the respondent (patentee) filed with a letter dated 14 November 2003 new claims forming the basis for a new main request for maintenance of the patent in amended form.

V. Oral proceedings took place on 15 December 2003.

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

The respondent requested that the appeal be dismissed and that the patent be maintained on the basis of the main request filed with a letter dated 14 November 2003 or alternatively on the basis of the auxiliary request filed during the oral proceedings.

VI. Claim 1 of the main request reads as follows:

"An absorbent composite comprising a matrix of fibers and superabsorbent material characterized by having at least about 50. weight percent superabsorbent material based on the combined weight of the fibers and the superabsorbent material, said superabsorbent material having a Deformation Under Load (DUL) of 0.4 millimeters or less and a Wicking Index (WI) of 12. centimeters or greater."

Claim 1 of the auxiliary request reads as follows:

"An absorbent composite comprising a matrix of fibers and superabsorbent material characterized by having at least about 50 weight percent superabsorbent material based on the combined weight of the fibers and the superabsorbent material, said at least 50 weight superabsorbent material having a particle size between 300 and 600 µm and a Deformation Under Load (DUL) of 0.4. millimeters or less and a Wicking Index (WI) of 12 centimeters or greater."

VII. In support of its requests appellant I relied essentially on the following submissions:

Since claim 1 of the main request referred in general to a superabsorbent material its scope included an absorbent composite comprising not only superabsorbent particles of a size within the range of 300 to 600 µm, but also outside this range, in particular small particles having a size below 300 µm. Such small particles would fill the spaces between the greater particles and would thereby impair the wicking ability of the superabsorbent material. Therefore it was clear that the wicking index was not an intrinsic feature of the superabsorbent material but one dependent on the particle size distribution within the superabsorbent material. As a consequence, claim 1 failed to give a clear teaching to the skilled person on how to select a superabsorbent material having a good ability to wick away fluid.

Claim 1 of the auxiliary request did not meet the requirements of Article 123(2) EPC because the application as filed did not disclose that the superabsorbent material comprised only particles of a size between 300 and 600 µm, but only that such particles were used when carrying out the test for measuring the deformation under load and the wicking index. Nor was the claim clear in that respect, contrary to Article 84 EPC, since it left open the possibility that the superabsorbent material comprised particles of a size outside the range of 300 to 600 µm.

VIII. Appellant II essentially submitted that according to the patent in suit both the wicking index and the deformation under load were measured on a fraction of the superabsorbent material, namely on particles having a size of 300 to 600 µm obtained after sieving the superabsorbent material. However, such a fraction could not be regarded as representative of the behaviour of the whole superabsorbent material as regards its ability to wick away fluid (wicking index) and its ability to maintain wicking channels when swollen (deformation under load). For instance, claim 1 of the main request included the case of a superabsorbent material consisting mainly of particles having a size smaller than 300 µm in which a very small amount of particles in the range of 300 to 600 µm was added. However, such small amount could not be representative of the behaviour of the entire superabsorbent material. Moreover, different values for the deformation under load and the wicking index were obtained if the tests described in the patent in suit were carried out on both sieved and unsieved superabsorbent material, as shown by the results of tests carried out by appellant II. The patent failed to specify how much of the superabsorbent material should consist of particles having a size in the range of 300 to 600 µm and it left to the skilled person the selection of a proper amount thereof. The patent, however, did not contain any information enabling the skilled person to infer whether any specific selections would fulfil the invention, ie whether the technical problem underlying the patent in suit would be effectively solved by any such selection.

Table I of the patent in suit did not support the respondent's allegation that the size of the particles was irrelevant for the performance of the invention. Indeed, table I related exclusively to the case of an absorbent composite comprising 50% superabsorbent material and 50% fluff whilst claim 1 of the main request was not so limited. Moreover, the results listed in table I were based on a comparison made with a commercially available diaper manufactured by the respondent itself and the results might look different if the comparison were made with other available diapers.

Claim 1 of the auxiliary request was ambiguous because it could either be interpreted as relating to an absorbent composite comprising superabsorbent material with only particles having a size in the range of 300 to 600 µm, or as relating to an absorbent composite comprising superabsorbent particles having a size in the range of 300 to 600 µm but also superabsorbent particles outside this range. For the first interpretation, which was the one intended by the respondent, there was no support in the application as filed, contrary to the requirements of Article 123(2) EPC, because the application as filed did not disclose that the sieving step could be dispensed with when carrying out the test for measuring the deformation under load and the wicking index of a superabsorbent material for use in the claimed absorbent. Moreover, superabsorbent particles of a size from 300 to 600 µm usually formed a minor portion only of the whole superabsorbent material, as shown for instance by document

D5: EP-A-0 339 461.

IX. The arguments of appellant III can be summarised as follows.

The removal of the term "about" in respect of the values for the deformation under load and the wicking index specified in claim 1 was contrary to the requirements of Article 84 and 123(2) EPC. In fact, with the tests for measuring the deformation under load and the wicking index disclosed in the patent in suit it was not possible to obtain precise figures, and therefore there was no support at all for any figure which was not "about".

As regards sufficiency of disclosure, appellant III concurred with appellant II's arguments and additionally submitted that in order to determine which specific content of superabsorbent particles having a size in the range of 300 to 600 µm was acceptable the skilled person should carry out performance evaluation tests of the kind described in the patent in suit for various absorbent articles having a different content of superabsorbent particles of a size in the range of 300 to 600 µm. This however resulted in an undue burden on the skilled person. Table I of the patent in suit did not contain any information about the particle size distribution in the samples and therefore could not support the allegation that the particle size distribution was irrelevant for the attainment of the desired technical effects. Furthermore, in the present case the burden of proof was on the respondent to show that the invention could be performed in the whole range claimed.

Also in respect of claim 1 of the auxiliary request appellant III essentially concurred with appellant II's arguments and added that although the application as filed disclosed that the test for measuring the deformation under load and the wicking index was carried out using superabsorbent particles which were sieved such as to have a size in the range of 300 to 600 µm, there was no disclosure to put the sieved particles only in an absorbent composite.

X. Appellant IV essentially agreed with the objections under Articles 84 and 123(2) EPC raised by appellant III, and additionally submitted that the presence of the expression "about 50 weight percent" rendered the claim unclear, because it did not define a precise limitation.

As regards sufficiency of disclosure, appellant IV essentially submitted that the test procedure disclosed in the patent in suit for determining the values of deformation under load and wicking index of the superabsorbent particles only gave information about the behaviour of a small fraction of the superabsorbent material, namely the fraction consisting of particles having a size within the range of 300 to 600 µm, but could not be used to evaluate the behaviour of the whole superabsorbent material which usually comprised a majority of particles outside that range. Moreover, there was no disclosure in the patent in suit of a method for determining the deformation under load and the wicking index of said whole superabsorbent material. Considering that claim 1 of the main request defined values for the deformation under load and the wicking index of the superabsorbent material as a whole ("said superabsorbent material having a Deformation Under Load..."), it followed that the invention was not sufficiently disclosed.

As regards claim 1 of the auxiliary request, appellant IV agreed with the other appellants that it lacked clarity but raised no objections under Article 123(2) EPC if claim 1 was understood to seek protection for an absorbent composite comprising only superabsorbent particles having a size in the range of 300 to 600 µm.

XI. The respondent disputed the appellant's views and essentially argued as follows.

Since the expression "about 50 weight percent" was already present in a dependent claim as granted, clarity thereof should not be an issue, in accordance with the case law of the boards of appeal. The removal of the term "about" in respect of the values for the deformation under load and the wicking index in claim 1 corresponded to the common practice of the examining divisions of the EPO according to which approximate terms in claims should be avoided. By means of this amendment, claim 1 was restricted to a precise value and thus defined a clear limitation. In any case, the claim had to be read with the eyes of a skilled person and not in a formalistic way.

Claim 1 of the main request required the absorbent composite to contain a superabsorbent material for which the deformation under load and the wicking index could be measured by means of the test disclosed in the patent in suit. Since the test required sieving out particles of a size between 300 to 600 µm, it was clear that the superabsorbent material referred to in claim 1 necessarily included an amount of such particles. The sieving step, which was common practice in the art, was necessary in order to compare superabsorbent materials of the same scale as they usually came in different particle-size distributions. Furthermore, the deformation under load and the wicking index were primarily intrinsic properties of the superabsorbent material, and the size range of 300 to 600 µm was the most common for superabsorbent particles. In any case, the appellants did not demonstrate the existence of any superabsorbent material for which the values of deformation under load and wicking index could be measured with the test procedure disclosed in the patent in suit, which measured values fell within the terms of claim 1, that failed to work well and thereby provide a solution to the problem underlying the patent in suit. The burden of proof concerning this issue was on the appellants. Moreover, for a particular superabsorbent material fulfilling the requirements of claim 1 in respect of deformation under load and wicking index, benefits were obtained across the whole range of particle-size distribution. Indeed, as evidenced by table I of the patent in suit, the size of the particles was essentially irrelevant for the performance of the invention. The deformation under load and the wicking index were parameters that predicted how a given material performed at any particle size. The contrary had not been demonstrated by the appellants.

Claim 1 of the auxiliary request was clearly restricted to an absorbent composite comprising only superabsorbent particles having a size in the range of 300 to 600 µm. Support for this feature was found in claims 1 and 19 of the patent as granted, read in conjunction with page 5. In fact, it was clear from the disclosure on page 5 that two possibilities were envisaged: either the superabsorbent material comprised only particles having a size in the range of 300 to 600 µm, or it comprised such particles and also particles having a size outside the range of 300 to 600 µm. The first possibility, which was more restricted, clearly represented a preferred embodiment of the invention.