In this appeal against the rejection of the opposition sufficiency of disclosure was the dominating issue.
Main request (claims as granted)
[2.1] Claim 1 refers to a pulverised water-absorbent resin powder which is characterised inter alia by having:
- a bulk density of not lower than 0.74 g/ml;
- an average particle diameter of 150 to 600 μm;
- a content of fine powders not higher than 10 wt%; and
- a water absorption capacity of not lower than 23 g/g […].
[2.1.1] According to the opposed patent, such a powder is obtained by a process which has the steps of first pulverising the particles and then grinding them, and it is this grinding step that is needed in order to obtain powders according to claim 1 having the required bulk density […]. More specifically, by way of the grinding step, the surfaces of the particles are smoothened by eliminating angular and pointed portions […] and as a result of the particle surfaces becoming smoothened (“rounded”), the required bulk density is obtained:
“Because the polymer particles become more rounded into a uniform shape by the grinding according to the present invention, the bulk density of the ground polymer is higher than that of the unground polymer, and is preferably not lower than 0.72 g/ml, … still more preferably 0.74~0.90 g/ml …” […].
[2.1.2] Independent product claim 1 does not however contain the feature of the particle surfaces being ground and thus smoothened. This claim therefore also covers non-smoothened particles having – inter alia – a bulk density not lower than 0.74 g/ml.
[2.1.3] As was not disputed by the [patent proprietor], there is no teaching in the patent as to how to prepare such non-smoothened particles; nor does such a teaching form part of the skilled person’s common general knowledge. Therefore, on the basis of the patent and common general knowledge, the skilled person is not able to prepare non-smoothened particles according to claim 1 having the required bulk density. This part of the invention is thus insufficiently disclosed.
[2.2] The [patent proprietor] argued during the oral proceedings (OPs) that by virtue of the parameters present in claim 1, i.e. the bulk density, the average particle diameter, the content of fine particles, and the water absorption capacity, the powders of claim 1 were inherently restricted to those with smoothened particle surfaces. No insufficiency with regard to powders having non-smoothened particle surfaces could therefore arise, since such powders would not be covered by claim 1.
The board does not agree with the [patent proprietor’s] argument.
Firstly, such an inherent restriction is not derivable from the opposed patent in the context of the bulk density. All that the patent discloses in this respect is that the inventive process contains the step of grinding and that by virtue of the resulting smoothened particle surfaces, a bulk density as required by claim 1 is obtained […]. This disclosure does however not permit the reverse conclusion to be drawn, namely that all powders having the required bulk density inherently have smoothened particle surfaces.
In fact, the only evidence available in this respect points to the opposite conclusion, namely that particles with the bulk density of claim 1 do not necessarily have smoothened surfaces. More specifically, D13 (example 4) discloses polymer particles with a bulk density within the range required by claim 1 (0.79 g/ml) that are “rock-like” and thus have a surface as shown in figure 2 of D13. As is apparent from this figure, this surface is non-smoothened.
Secondly, no reasons were provided by the [patent proprietor] why the further parameters of claim 1, i.e. the average particle diameter, the content of fine particles and the water absorption capacity, inherently restrict the claimed powders to those having smoothened particle surfaces.
There is thus no reason to believe that the parameters of claim 1 inherently restrict the claimed powder such that its particles have smoothened surfaces.
[2.3] According to a second line of argument put forward by the [patent proprietor], claim 1 was inherently restricted to particles having been ground and thus having smoothened surfaces since it was essential according to the description of the patent that the pulverized particles were subjected to a grinding step in order to obtain the bulk density of claim 1. This argument in fact is different from the [patent proprietor’s] first argument […] in that it is now the description of the opposed patent rather than the parameters in the claim which is said to restrict the claim to powders with smoothened particle surfaces.
[2.3.1] The board acknowledges that it can be deduced from the description of the opposed patent that the process disclosed in the patent only allows for the preparation of powders with smoothened particle surfaces […]. It is also true that according to the description, it is thus not possible to prepare powders via this process that have non-smoothened particle surfaces having a bulk density of not less than 0.72 g/ml.
[2.3.2] The [patent proprietor’s] conclusion from this, namely that these powders are therefore excluded from claim 1, cannot however be accepted. This argument could only succeed if one were to accept that the description of the patent in this case restricts the scope of the claim on to its normal and ordinary reading.
[2.3.3] There is however no legal basis for such an approach. More specifically, the relevant legal provisions in the EPC dealing with this issue are A 84 and A 69 (and its protocol), the latter provisions in particular being intended to assist the patent proprietor in contending for an interpretation of a claim that is less rather than more restricted than its wording warrants. Therefore, if in proceedings before the EPO the proprietor wishes to argue for a narrow scope of a claim, this should be on the basis of the ordinary wording of the claim, and not on the basis of something appearing only in the description (T 1404/05 [3.4,3.6]). See also T 681/01 [2.1.1], where the board emphasized that the normal rule of claim construction is that the terms used in a claim should be given their ordinary meaning in the context of the claim in which they appear. The description may not be used to rewrite the claim and redefine the technical features required by the claim in a way not warranted by the wording of the claim itself. In particular the description cannot be relied on to exclude subject-matter from the claim which the ordinary meaning of the terms used would include as part of what is claimed.
[2.3.4] The [patent proprietor’s] argument that the description inherently restricts claim 1 to powders with smoothened particle surfaces is also not accepted for the following further reason: The [patent proprietor’s] argument implies that embodiments covered by the scope of claim 1, namely powders with non-smoothened particle surfaces having inter alia a density of not less than 0.72 g/ml, are excluded from the claim because it can be deduced from the description that these powders cannot be prepared by the process disclosed in the description. This would lead to the absurd situation that because it can be deduced from the description that a claim is not enabled, the claim cannot be attacked under A 83 or A 100(b).
[2.3.5] In summary, embodiments that are covered by the scope of a claim on its ordinary reading are not to be regarded as excluded merely because it can be deduced from the description that they are not workable.
[2.4] Therefore, claim 1 in the present case covers powders with non-smoothened particle surfaces. As the skilled person would not be able to obtain such powders on the basis of the teaching in the patent or his common general knowledge, this part of the invention is insufficiently disclosed. Hence, the ground of opposition under A 100(b) prejudices the maintenance of the patent as granted. The main request thus is not allowable.
[2.5] In view of this, the [opponent’s] further insufficiency objections against the main request need not be dealt with as far as the main request is concerned.
First auxiliary request
[4.1] Independent process claim 1 refers to a production process for a pulverised water-absorbent resin powder, which comprises the steps of:
- obtaining crosslinked polymer particles by way of an aqueous solution polymerisation step,
- pulverising the crosslinked polymer,
- grinding the resultant crosslinked polymer particles until the bulk density thereof increases to not lower than 0.72 g/ml, and
- surface cross-linking the ground particles.
[4.2] The insufficiency objection discussed with regard to the main request, namely that granted claim 1 covers insufficiently disclosed powders with non-smoothened particle surfaces, is no longer applicable to the first auxiliary request as the only independent claim (claim 1) is now directed to a process which requires grinding and thus smoothening of the polymer particles.
[4.3] However, the other insufficiency objections raised in the context of the main request still apply to the first auxiliary request and therefore will be discussed in the following.
[4.4] More particularly, the [opponent] raised a further insufficiency objection against the main request on the basis of D2. According to the [opponent], the experiments described in this document show that carrying out the process steps as defined in claim 1 (claim 10 of the main request), in particular the grinding step, is not sufficient to obtain the bulk density required by the present claims. A further technical measure is thus necessary in order to achieve the required bulk density. As no teaching is present in the patent as regards this technical measure, the skilled person would not know how to obtain the required bulk density and thus the invention as defined in claim 1 is insufficiently disclosed.
[4.4.1] D2 describes experiments in which the [opponent] attempted to repeat example 1 of the opposed patent. In these experiments, acrylate polymers were prepared using various temperature profiles during polymerisation […]. In two different experiments using two different pulverisers, the polymers were then pulverised, ground and classified (isolation of the 212-850 mym fraction) in a way similar to that in example 1 of the opposed patent […]. The obtained fractions were subsequently surface crosslinked.
The bulk densities of the obtained samples are shown in the table on page 12 of D2. As can be seen from this table, none of the pulverised and ground samples (denoted Ex1_1, Ex1_2, Ex1_3, Ex1_4, Ex2_1, Ex2_2, Ex2_3 and Ex2_4) has a bulk density equal to or above 0.72 g/ml as required by claim 1 of the first auxiliary request.
Consequently, even though in the experiments of D2 the process steps of claim 1 were carried out, the bulk densities were not as required by this claim. It therefore seems to be credible to the board that the steps of claim 1 as such are not sufficient to obtain the required bulk density.
[4.4.2] In the board’s view, however, this does not establish insufficiency of disclosure. In the present case, it is self-evident that in order to obtain the required bulk density by the steps of claim 1, the bulk density of the starting material before grinding must not be too low, since grinding can increase the bulk density only to a certain extent. The skilled person trying to work the invention would therefore approach the task appreciating that the bulk density of the pulverised particles before grinding must be sufficiently high so as to obtain the required bulk density after grinding.
It can be deduced from the opposed patent that bulk densities before grinding in the range of e.g. 0.64 g/ml to 0.68 g/ml are suitable in this respect (see comparative examples 1 to 7, where bulk density values of non-ground samples are reported).
D2 does not contain any information as regards the bulk densities of the particles before the grinding step and it was acknowledged by the [opponent] during the OPs before the board that in fact these values may have been below the values used in the opposed patent. Hence, D2 does not establish that the skilled person carrying out the process as defined by claim 1, when appropriately construed, would be unable to obtain the required bulk density.
[4.5] The [opponent] raised a further insufficiency objection in view of D3. This document describes experiments where two commercially available samples were ground but where only bulk densities below the lower limit of claim 1 were obtained. According to the [opponent], in the same way as with D2, these experiments proved that the process steps of claim 1, in particular grinding, were not sufficient to obtain the bulk densities required by this claim.
The [patent proprietor] stated on page 5 of its letter of 17 November 2011 that the commercial polymers used in D3 had already been surface crosslinked before they were used by the [opponent] in its experiments. This statement was reiterated during the OPs before the board and the [opponent] did not dispute it, either in the written or during the OPs. Under these circumstances, the board can only accept that in the experiments described in D3 the surface crosslinking step was applied before the polymers were ground. These experiments thus differ from the process of claim 1 in that surface crosslinking is carried out before grinding while claim 1 requires the opposite, ie surface crosslinking subsequent to grinding. Therefore, contrary to the [opponent’s] assertion, D3 does not demonstrate that the process steps of claim 1 are not sufficient to obtain a bulk density as required by this claim.
[4.6] The [opponent] finally argued with regard to the main request that claim 1 contained an open-ended range for the water absorption capacity (“not lower than 23 (g/g)”) and thus covered powders with non-achievably high water absorption capacities.
[4.6.1] The only claim of the first auxiliary request containing such an open-ended range is dependent claim 6.
[4.6.2] This claim, by way of its dependency on claim 1, contains the further feature that the bulk density of the ground particles is not lower than 0.72 g/ml. The lower the bulk density of a powder, the looser are the particles of the powder packed and the greater are the free spaces remaining between these particles, which in turn means the more can water penetrate into and thus be absorbed by the powder. In other words, with decreasing bulk density, water absorption capacity increases. Consequently, the lower limit of the bulk density of 0.72 g/ml implies an upper limit for the water absorption capacity. The [opponent’s] assertion that claim 6 lacks any upper limit for the water absorption capacity is thus not valid and, accordingly, no insufficiency arises in this respect. This is in line with the conclusion in T 487/89 [3.5] that if a claim which contains an open-ended range seeks to embrace values which should be as high as can be attained above a specified minimum level, while at the same time complying with the other parameters of the claim, then such open-ended parameters are normally unobjectionable under A 83 (see also T 129/88 [2.1.4] and T 773/06 [2.1]).
[4.6.3] The [opponent] referred in this respect to decision T 1008/02 and argued that according to this decision, a missing upper limit for the water absorption capacity leads to insufficiency of disclosure.
This decision concerned a case where the relevant claim did not contain an upper limit for an absorbency under load. The present board acknowledges that absorbency under load is related to the water absorption capacity as referred to in present claim 6. However, contrary to the present claim 6, the claim in T 1008/02 [II] did not contain any lower limit for the bulk density and thus, contrary to the present case, there was no further parameter which provided an implicit upper limit for the absorbency under load. The decision is thus not relevant to the present case.
[4.6.4] The [opponent] finally argued that in the examples of the opposed patent, water absorption capacity decreased with decreasing bulk density, contrary to the above consideration […]. This is however not correct. More specifically, in none of the examples using the same type of polymer does water absorption capacity (whether under load or under no load) decrease when the bulk density decreases (examples 1 to 10).
[4.7] In view of the above, the invention as defined by the claims of the first auxiliary request is sufficiently disclosed.
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