T 0081/13 - Clarity trap

Key points:

• In this examination appeal, claim 1 as filed contained a parameter feature (viscosity) which was deemed to be unclear. "The appellant argued that an unclear and unmeasurable viscosity value was not essential and could be omitted for this reason from the claim. This omission should also be possible to escape the Aricle 84 EPC/Article 123(2) EPC "squeeze" which leads to an "inescapable trap".
• The Board: " In reality, if the omission of such feature reflecting essential properties of a claimed product is not possible, its replacement by an equivalent feature providing inevitably the same essential property can be considered as normally feasible. This is usually possible through the incorporation of adequate technical features able to provide inevitably said property. As a last resort, the claimed subject-matter could even have taken the form of an exemplified subject-matter. " However, in the present case, the description did not give information about the components of the composition.
• The viscosity feature was: "a viscosity of less than 30,000 mPa.s (centipoise) as determined by a Brookfield viscometer model RVTDV-II, spindle E at 5 rpm prior to addition of the propellant". This feature was unclear because the temperature and shear rate were not specified. 

EPO T 0081/13 - link

Reasons for the Decision

1. Main request - Clarity

1.1 The subject-matter of claim 1 of the main request relates to an oral care mousse specified by its viscosity, to be specific "a viscosity of less than 30,000 mPa.s (centipoise) as determined by a Brookfield viscometer model RVTDV-II, spindle E at 5 rpm prior to addition of the propellant".

This parameter is a feature contributing to the definition of the claimed dentifrice composition, to which it confers particular properties, and as such can only be seen as an essential feature. The viscosity allows in particular the formation of a mousse with the evaporating propellant.

In addition, the broadness of the definition of the claimed dentifrice composition, limited to the presence of an unquantified and unidentified surfactant and humectant renders the viscosity feature even more essential.

1.2 There is however no further indication in claim 1 on the conditions at which the measurement of this parameter takes place. The parameter of viscosity is indeed given without the indication of the shear rate or temperature of measurement. Yet these informations are essential for the measurement of the viscosity, which is dependent thereon; it is common general knowledge that the temperature and the shear rate used to measure the viscosity influence the measured results.

1.2.1 First, viscosity is affected by the temperature, in that when the temperature increases, the viscosity decreases, and some chemical products are very sensitive to a temperature variation, which will result in a significant change in the viscosity measured. It is common general knowledge that there are normal variations in viscosity of about 15-20% over the normal temperature span of 20-30°C, even for products such as water. It is thus crucial to control the temperature during any viscosity measurement. The absence of any indication on the temperature at which the measurement is made results in an uncertainty as to the claimed viscosity value.

The argument of the appellant that the skilled person would understand that the viscosity can only be measured at room temperature fails for following reasons:

(a) The term "room temperature", usually a temperature comprised between 20°C and 25°C, remains so vague and indeterminate that it cannot serve as a reliable means of indicating with sufficient precision and clarity the limiting values for the viscosities of the components as now specified in claim 1, in view of the dependency between the viscosity and the temperature at which it is measured and that even within a range of five degrees Centigrade the viscosity value may vary in a relevant way.

(b) The present invention relates to an oral care mousse with a dentifrice composition to be administered into the oral cavity. It is not convincing that, in the absence of any mention of temperature in the application in suit, the measurement necessarily takes place at room temperature since the skilled person may for convenience choose to make the measurement of the viscosity of the composition to be administered to the oral cavity at a higher temperature, namely at a temperature closer to the temperature of the oral cavity, for instance 30ºC.

1.2.2 Secondly, viscosity is also affected by the shear rate at which the measurement is made. When a material is to be subjected to a variety of shear rates in processing or use, as it appears to be the case with the composition of the present application, which has to be expelled from a dispenser, it is essential to know its viscosity at the projected shear rate. The measurement under different shear rates will also give a variable result in the viscosity measurement. The absence of the shear rate results thus also in uncertainty as to the exact limits of the scope of claim 1.

1.2.3 Therefore, claim 1 relates to an attempt to delimit the subject-matter for which protection is sought by means of a parameter, namely a maximum viscosity value, which has been defined incompletely and for which the lack of definition cannot be completed in a standard manner by the skilled person's general knowledge. It follows that the lack of information regarding the exact conditions under which the viscosity limit of claim 1 is to be determined, results in uncertainty as to the exact limits of the scope of claim 1. Therefore, the viscosity cannot be considered to be clearly indicated and the matter for which protection is sought is not sufficiently defined, so that the subject-matter of claim 1 is unclear.

The main request does not meet the requirements of Article 84 EPC.

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3. Auxiliary request 8

3.1 The subject-matter of claim 1 of auxiliary request 8 has been reformulated with the omission of the viscosity feature, namely "a viscosity of less than 30,000 mPa.s (centipoise) as determined by a Brookfield viscometer model RVTDV-II, spindle E at 5 rpm prior to addition of the propellant".

3.2 This viscosity feature was present in all independent claims of the application as filed in relationship with the dentifrice composition.

As to the description, the only passage mentioning the dentifrice composition in general terms is in paragraph [0003]. Said passage mentions that "the mousse includes (a) a dentifrice composition that contains at least a surfactant and a humectant; and (b) a compressed liquid propellant that has a boiling point of less than about -10 deg. C". This passage is immediately followed, in the next sentence, by the specification that "the dentifrice composition has a viscosity of less than about 30,000 centipoises". It therefore cannot constitute a basis for the omission of the viscosity requirements.

Consequently, the dentifrice composition is not disclosed in the description or in the claims as originally field in isolation from its viscosity requirements. The limitation on viscosity appears thus as an essential parameter defining the claimed dentifrice composition, and not as an option or a preferred embodiment. The omission of such essential feature results in an undisclosed generalisation.

3.3 The appellant argued that an unclear and unmeasurable viscosity value was not essential and could be omitted for this reason from the claim. This omission should also be possible to escape the Aricle 84 EPC/Article 123(2) EPC "squeeze" which leads to an "inescapable trap".

3.3.1 The Board does not agree. It was the choice of the appellant to define an essential characteristic of the invention by a parameter. This parameter revealed to be unclear but remains however an essential feature since, even unclear, it confers to the mousse composition a particular aspect and reflects a composition having specific and essential properties. This "not so high" viscosity allows in particular, as mentioned by the appellant, the formation of a mousse with the evaporating propellant. The essentiality of this property renders therefore necessary the presence in claim 1 of a feature allowing its performance, in the form of the viscosity parameter or of an alternative.

In reality, if the omission of such feature reflecting essential properties of a claimed product is not possible, its replacement by an equivalent feature providing inevitably the same essential property can be considered as normally feasible. This is usually possible through the incorporation of adequate technical features able to provide inevitably said property. As a last resort, the claimed subject-matter could even have taken the form of an exemplified subject-matter. It therefore cannot be concluded that the presence of an unclear essential feature in a claim inevitably leads to an "inescapable trap".

In the present case, and according to the appellant, the viscosity of a dentifrice composition changes negligibly over typical user temperatures, and is certainly always below the claimed high threshold of 30,000 centipoises. This argument appears to be confirmed by the alternative maximal viscosities disclosed in the description, which are below 23,000 or 15,000 centipoise (see par. [0018]). In view of this argument, a theoretically feasible alternative way to define the dentifrice composition achieving the specific aspect and property of the dentifrice composition could thus have been reflected in the claim through the the presence of specific compounds in specific amounts or ranges, which could have replaced the viscosity parameter. This replacement could have been done under the condition that the dentifrice composition defined by such specific compounds in specific amounts should have had inevitably a viscosity lower than 30,000 centipoises measured under any temperature condition, i.e. 18°C, 20°C, 25 or 30°C.

If this solution to the said "Article 84 EPC/Article 123(2) EPC squeeze" does not appear to be realisable in the present case, it is because the description of the present application does not provide sufficient teaching for defining the dentifrice composition by means of specific compounds or class of compounds in specific amounts, in a broader way than the examples. Apart from the surfactant and humectant, the description is totally silent on the amounts of the remaining components of the dentifrice composition, in particular those which may also have an influence on the viscosity of the dentifrice composition, such as for instance the binder or the abrasive ( par. [0010]-[0017]). Yet these components are essential components of a dentifrice composition. The application as originally filed presents thus a disclosure deficiency and if there is an inescapable trap, it is rather linked to this deficiency.

3.4 The oral care mousse composition is thus not disclosed independently from its viscosity in any part of the application as originally filed. The omission of this parameter constitutes therefore an unallowable generalisation not derivable directly and unambiguously from the application as originally filed.

Auxiliary request 8 does not meet the requirements of Article 123(2) EPC.