T 0274/16 - Consisting essentially of

Key points

• The Board recalls that according to established case law, "the expression "consisting essentially of" is to be interpreted as allowing the presence of amounts of other components in addition to the mandatory components, provided that the essential characteristics of the claimed composition are not materially affected by their presence". 

EPO T 0274/16 - link

1.2 According to the case law (see e.g. decision T 1730/09, which refers inter alia to T 759/91, T 522/91 and T 472/88), the expression "consisting essentially of" is to be interpreted as allowing the presence of amounts of other components in addition to the mandatory components, provided that the essential characteristics of the claimed composition are not materially affected by their presence (see Reasons 1.2.3). In particular, the latter passage contains the following statement: "the wording 'consisting essentially of' allows [...] that the composition of claim 1 [...] consists of the mandatory components listed in the claims and can contain additionally only other components which do not materially affect the essential [...] characteristics of the composition, e.g. minor amounts of impurities".

In other words, this means that the amounts of other components must be so minor as to leave the essential characteristics of the mandatory components unchanged. The passage leaves no doubt that the mandatory components, and not the other components, are responsible for the properties of the composition (see the wording "consists of the mandatory components"). Thus, even if additional compounds with properties similar/identical to the mandatory components are present, they have to be added in such amounts that they are not the main contributor to the essential characteristics of the composition ("e.g. minor amounts of impurities").

Decision T 759/10, which the respondent also cited, defines said expression in similar terms, namely that specific further components not materially affecting the essential characteristics of the texturising agent can be present (see Reasons 3.4).

1.3 It follows from the above that claim 1 of the main request is to be interpreted such that the claimed additive contains one or more hydroxyalkyl guar derivatives having an MS of from 0.7 to 3 as the major component(s). Additional components which do not materially affect the essential characteristics of said mandatory components may be contained only in minor amounts.

By contrast, claim 7, which depends on claim 1, requires the additive to contain between 66.66 and 80%, i.e. the major part, of cellulose ether.

1.4 The presence of two contradicting and even mutually exclusive requirements can, in the present case, not be simply regarded as an issue concerning lack of clarity, since the skilled person is not in a position to reproduce compositions meeting both requirements at the same time. The objection concerns not only individualised embodiments, but a major part of the claimed invention.

Therefore the board concludes that the main request does not meet the requirements as defined in Article 83 EPC and is therefore to be rejected.