Interpretational Spotlight: “Half Dried”

In this revocation appeal, claim 1 of the main request before the Board read:

A production process of a hydrophilic crosslinked polymer, comprising the steps of polymerizing an aqueous solution including a hydrophilic monomer and a crosslinking agent to obtain a hydrogel crosslinked polymer, and drying the hydrogel crosslinked polymer, thus obtaining the hydrophilic polymer, with the step of drying the hydrogel crosslinked polymer comprising the steps of:
(i) carrying out a first-step drying of hydrogel crosslinked polymer obtained by the polymerization in a static state to obtain a half-dried product, until it becomes possible to disintegrate an aggregate of the particulate hydrogel crosslinked polymer; then
(ii) disintegrating the half-dried product obtained by the first-step drying into a particle size of 20 mm or less; and then
(iii)carrying out a second-step drying of the half-dried product having a particle size of 20 mm or less in a stirred state and/or a fluidized state.

The Board dealt with the question whether this claim was based on an inadmissible extension:

[2] Claim 1 of the main request corresponds to claim 1 as granted, which, apart from the insertion of the term “half-dried”, resulted from a rewording of claim 1 as originally filed. It is not disputed that any difference in meaning between claim 1 as granted and claim 1 as originally filed could only result from the definition that the product resulting from drying step (i) is a “half-dried” product. It is also not disputed that the term “half-dried product” as such is only disclosed in the examples of the application as filed, the details of which are not given in claim 1 as granted.

Hence, the question to be answered is whether the introduction of the term “half-dried product” into claim 1 results in technical information that could not be directly and unambiguously derived from the application as filed.

In particular whether the introduction of the term “half-dried” amounts to an undue generalization of the disclosure of the examples of the application as filed, as found by the Opposition Division and argued by the [opponents].

[3] Normally, terms used in a claim should be given their ordinary meaning in the context of that claim; in case of unclarity, the disclosure of the patent may be taken into account, ruling out interpretations that are illogical or do not make technical sense.

The wording “half-dried” by its nature does not provide an exact quantitative definition of the proportion of water removed after the first drying step, in particular it does not indicate that exactly 50 % of the water has been removed. It rather expresses the general idea that the first drying step leads to a product which is semi-, partly, not fully dried.

[4] From the context of claim 1, according to which the boundary between the first drying step (i) and the disintegration step (ii) is defined as the point at which it is possible to disintegrate the aggregate of the hydrogel crosslinked polymer resulting from drying step (i), it is also clear that the above indicated meaning of “half-dried” does not provide any precise restriction on the claimed subject-matter with regard to the proportion of water removed during the first drying step. This view is supported by the disclosure of the invention in the paragraph bridging pages 4 and 5, on page 5, lines 25-27 and in the first paragraph of page 7 of the application as filed.

[5] It can be accepted that the amount of water removed until aggregates have formed and can be disintegrated may depend on many factors, in particular on the chemical nature of the polymer and its structure, and therefore will not necessarily be exactly 50% of the water originally present. This is consistent with the information provided in the first full paragraph of page 5 of the original application, according to which the water content of the hydrogel crosslinked polymer subjected to the first drying step usually has a water content in the range of 50-80 wt%. It can also be deduced from the information given in the paragraph bridging pages 5 and 6 of the application as filed, where it is indicated that hydrogel crosslinked polymers obtained in the course of the first drying step should not have a water content higher than 25 wt.%, as it would result in a difficult disintegration of the polymer particles.

[6] The above indicated interpretation of the term “half-dried” is also consistent with the use, on page 5, line 10 of the application as filed, of the expression “in the midway of drying” which describes the point in time in the process of drying when aggregates are formed. It is also in line with the use of that term in the various examples and comparative examples of the application as filed for describing different situations, corresponding to various proportions of water removed after the first drying step, which are all much higher than 50%.

[7] It follows from the above that the term “half-dried product” as used in the examples of the application as filed merely expresses the general idea that the first drying step leads to a product that is semi-, partly, or not fully dried, or, in other words, still contains some noteworthy amount of water, and that it is not associated with any specific water content of the polymer.

[8] The [opponents’] argument that comparative example 1 of the patent in suit would now fall within the ambit of claim 1, as the term half-dried also allows content of water after the first drying step as high as 20,9 wt%, fails to convince. In view of the use of the same expression “half-dried product” in the examples and comparative example 1 of the application as filed, and the indication in the various passages on pages 5 and 6 cited above of the amounts of water usually present in the hydrogel crosslinked polymer before and after the first drying step, it is already apparent that the very use of the expression “half-dried” in the application as filed is not decisive in determining whether an embodiment falls within the ambit of original claim 1 or not. The decisive point is the formation of aggregates that may be disintegrated, which information was present both in the original claims as well as in the claims as granted, and which is therefore not open to clarity objections as raised by the [opponents]. The method described in comparative example 1 does not qualify as an embodiment of either claim 1 as filed or claim 1 as granted by virtue of the fact that the “half-dried” polymer was not disintegrated and dried according to steps ii) and iii) of present claim 1.

[9] It follows from the above that the result of the introduction of the term “half-dried” in claim 1 as originally filed is not a claim 1 as granted that comprises technical information not directly and unambiguously derivable from the application as filed. It does not change the meaning of the claim and it does not allow scope for any interpretation extending beyond the teaching of the application as filed.

Decisions T 792/94 and T 1067/02 cited by the [opponents], which concern a situation where the meaning of the claim could be held to have been changed by insertion of an ambiguous feature, are therefore of no relevance for the present case. 

[10] Hence, the Board comes to the conclusion that the subject-matter of claim 1 as granted, i.e. claim 1 of the present main request, does not extend beyond the content of the application as filed.

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