T 192/09 – Some Kind Of Restriction

This appeal was filed against the revocation of the patent under consideration by the Opposition Division.

Claim 1 of the main request before the Board read:

A formaldehyde-free aqueous binder composition comprising:

a binder component (A) obtainable by reacting at least one alkanolamine with at least one carboxylic anhydride and, optionally, treating the reaction product with a base; and a binder component (B) which comprises at least one carbohydrate; wherein binder component (A) comprises the reaction product of at least one alkanolamine with at least one carboxylic anhydride in an equivalent ratio of amine and hydroxy groups (NH+OH) to carboxy groups (COOH) of at least 0.4; and wherein the equivalent ratio of amine and hydroxy groups (NH+OH) to carboxy groups (COOH) in the final binder composition, including binder components (A) and (B), is 2.0 or less. (my emphasis)

The Board had something to say on the interpretation of this claim:

[3.1] Claim 1 of the main request contains two (NH+OH)/(COOH) ratios: one referring to component A, the second referring to “the final binder composition, including binder components (A) and (B)”.

[3.1.1] Component A is defined in the first part of claim 1 of the main request as being obtainable by reacting at least one alkanolamine and at least one carboxylic anhydride and in the second part as comprising the reaction product of the aforementioned compounds in an equivalent ratio of (NH+OH) groups to (COOH) groups of at least 0.4. From this wording it is ambiguous whether what is meant is the proportion of functional groups based on the starting materials or that present in the final product.

[3.1.2] According to paragraph [0020] of the patent in suit, “In the preparation” of component A the proportion of alkanolamine and carboxylic anhydride is selected such that the (NH+OH)/(COOH) ratio is at least 0.4. This wording suggests that the ratio refers to the starting materials.

[3.1.3] According to paragraph [0021] the properties of the final binder composition, including binder components (A) and (B), such as curing behaviour, durability and humidity resistance are determined by the total ratio of reactive groups present (emphasis of the Board). This text appears to refer to the final binder.

[3.1.4] Thus on the one hand the description and claims appear to be referring to the ratio of functional groups in the starting materials, at least as far as the first component is concerned. However in another respect, the content of functional groups present in the final binder, i.e. the reaction product of these starting materials, is referred to.

[3.1.5] The ambiguity in the claims is exacerbated by the use of the wording “comprising” indicating that other materials, also such containing OH, NH or COOH functional groups may be present. Among the “other components” permitted are, according to paragraph [0033] of the patent, ß-hydroxyalkylamides, i.e. a compound containing hydroxy groups, citric and adipic acids, i.e. components containing carboxyl groups. The presence of any such compound would clearly affect the (NH+OH)/(COOH) ratio.

[3.1.6] The examples do not assist in clarifying the matter. Examples 1-4, disclosing the preparation of the binder component A, report the quantities of starting materials employed and also give the ratio of functional groups in the product “obtained”. However, the latter is identical to the ratio of functional groups as calculated on the basis of the amounts of starting materials employed. Since a reaction would imply that the functional groups in the starting materials have been consumed – otherwise there would be no reaction – it appears that the information in the examples does not in fact relate to the final product but to the starting materials.

[3.1.7] To prepare the final binder in the examples a commercial carbohydrate component is added, identified as “Cerestar® 01411”. According to paragraph [0030] of the patent in suit this is a composition of 3% dextrose, 12% maltose, 16% maltotriose and 69% “higher sugars”. It is also reported in paragraph [0051] that this material has a dextrose equivalent of 30. This information is insufficient to disclose the content of functional groups, especially OH groups in the carbohydrate since 69% of the composition of that carbohydrate component is unknown. Furthermore it is not even indicated on what the percentages are based (mole, mass, volume?). The reported dextrose equivalent has not been demonstrated to provide, either directly or indirectly, the missing information. On the contrary, the dextrose equivalent is a measure of the reducing power of the sugar, i.e. relates to the content of CHO groups but not to OH groups. This information was provided by the [opponent], referring to a Wikipedia extract, and was not contradicted by the [patent proprietor].

[3.1.8] It is a technically sensible interpretation that the (NH+OH)/(COOH) ratio relates to the final product according to the wording of the claims. The interpretation that the ratio refers to the starting materials would not only go against the wording of the claims, but is also not supported by any information that could be obtained from the description and examples, in particular as regards the presence of other components. Furthermore, the Board doubts that it would be “technically sensible” to define a two component system by features which would no longer be present therein, such as the proportions of starting materials of one of the components thereof.

[3.1.9] The consequence of all this is that, although it is clear that the ratios specified in the claim impose a restriction on the subject matter thereof, in particular on the quantities of the compounds used in the binder, the precise limits and nature of this restriction are unclear. As a result the only possible interpretation of the claims that is consistent with the wording thereof is that there is some kind of restriction on the proportions of compounds present, but not what this restriction actually is.

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