T 0435/91 (Detergents) 09-03-1994

Reasons for the Decision

1. The appeal is admissible.

2. Main request

2.1. Claim 1 according to this request differs from Claim 1 allowed by the decision under appeal in respect of an obvious correction in the disclaimer which excludes the known composition of Example F of document (3). This amendment is not objectionable under Article 123(2) and (3) EPC.

2.2. The main issue that was argued in respect of this request was whether or not its subject-matter met the requirement of Article 100(b) EPC, i.e. whether or not the patent disclosed the claimed invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.

2.2.1. There is no dispute that a skilled person can establish whether or not a surfactant composition exists in the hexagonal liquid crystal phase (see the patent specification, page 6, lines 3 to 8). Furthermore the feasibility of the worked examples, in which the "additive" is either urea or sodium toluenesulfonate, remained unchallenged. Thus it is clear that the patent discloses at least one way to carry out the invention and that it is possible to determine whether or not any particular composition meets the definition of the invention as set out in Claim 1.

There is dispute, however, as to whether or not the subject-matter of Claim 1 as a whole can be carried out by the person skilled in the art, because one of its essential technical features, the "additive" (b), is defined only by its function.

In the Board's judgment the criteria for determining the sufficiency of the disclosure are the same for all inventions, irrespective of the way in which they are defined, be it by way of structural terms of their technical features or by their function. In both cases the requirement of sufficient disclosure can only mean that the whole subject-matter that is defined in the claims, and not only a part of it, must be capable of being carried out by the skilled person without the burden of an undue amount of experimentation or the application of inventive ingenuity.

The peculiarity of the "functional" definition of a component of a composition of matter resides in the fact that this component is not characterised in structural terms, but by means of its effect. Thus this mode of definition does not relate to a tangible component or group of components, but comprises an indefinite and abstract host of possible alternatives, which may have quite different chemical compositions, as long as they achieve the desired result. Consequently, they must all be available to the skilled person if the definition, and the claim of which it forms a part, is to meet the requirements of Article 83 or 100(b) EPC. This approach is based on the general legal principle that the protection covered by a patent should correspond to the technical contribution to the art made by the disclosure of the invention described therein, which excludes that the patent monopoly be extended to subject-matter which, after reading the patent specification, would still not be at the disposal of the skilled person (see also points 3.4 and 3.5 of Decision T 409/91 of 18 March 1993 (to be published in OJ EPO; for Headnote see OJ 11/93, page XVII).

There cannot, of course, be a clear-cut answer to the question of how many details in a specification are required in order to allow its reduction to practice within the comprehensive whole ambit of the claim, since this question can only be decided on the basis of the facts of each individual case. Nevertheless, it is clear that the available information must enable the skilled person to achieve the envisaged result within the whole ambit of the claim containing the respective "functional" definition without undue difficulty, and that therefore the description with or without the relevant common general knowledge must provide a fully self-sufficient technical concept as to how this result is to be achieved.

It has therefore to be established whether or not the present specification discloses a single embodiment or a technical concept fit for generalisation which makes available to the skilled person the host of variants encompassed by the respective "functional" definition of the said claim. In this respect, the Respondent had admitted during the oral proceedings that it was not possible to identify, on the basis of the information contained in the patent specification and taking into account the common general knowledge, other compounds than those specifically mentioned, i.e. "hydrotropes", which could reasonably be expected to bring about the desired effect.

Thus, it is clear that the above definition of the additive is not more than an invitation to perform a research programme in order to find other "additives" which meet the "functional" requirement set out in Claim 1. In other words, through this definition in the present claim the Respondent tries to claim not only the solution of the technical problem of providing surfactant compositions in the form of a hexagonal liquid crystal gel phase made available to the person skilled in the art by the disclosure in the patent specification, but, in addition, all other possible solutions of this problem which are based on the "principle" of mixing a surfactant composition (a) as defined in Claim 1 with a "suitable additive" and water, without giving any or any useful technical guidance as to how to obtain, with a reasonable expectation of success, further suitable "additives" which are not "hydrotropes". Neither the patent specification nor the relevant common general knowledge provide guidance as to how these further additives may be traced out or according to which criteria they might be selected. Therefore the Board holds that the patent does not disclose a self-sufficient technical concept which adequately corresponds to the "functional" definition used for the "additive" (b) in the present Claim 1. Thus, pursuant to Article 100(b) EPC, the patent cannot therefore be maintained on that basis.

2.2.2. The Respondent referred to several earlier decisions of the Boards of Appeal, which, in his opinion, supported the legal proposition that the requirement of Article 100(b) EPC would, as a matter of principle, always be satisfied by the disclosure of only one way of carrying out the invention, e.g. by a worked example, the repetition of which resulted in obtaining an embodiment of that invention. However, the decisions referred to do not support such a broad proposition, since the Respondent has not relied on the whole content of these decisions but only on selected parts of them.

In particular, it is not adequate to take the finding in point 3.1.5 of Decision T 292/85 (OJ EPO 1989, 275) out of its context. It is not only stated there, as quoted by the Respondent, that an "invention is sufficiently disclosed if at least one way of carrying out the invention is clearly indicated enabling the skilled person to carry out the invention", but in the next sentence it is made clear that "any non-availability of some particular variants of a functionally defined component feature of the invention is immaterial to sufficiency as long as there are suitable variants known to the skilled person through the disclosure or common general knowledge which provide the same effect for the invention" (emphasis added). Accordingly, this decision is inter alia based on the finding of fact that the application concerned made enough choice of suitable variants of the specifically disclosed embodiments available (point 3.1.3 of the reasons). Moreover, in respect of the "functional" expression "suitable bacterium" it was pointed out that the applicability of the claimed method to any kind or most species of bacteria has not been effectively challenged (point 3.2.2 of the reasons). Similar findings of fact concerned the remaining "functional" definitions in the considered claim (see e.g. point 3.4.3 of the reasons). Thus this decision does not support the Respondent's much broader legal proposition. Similarly, the reasons given in chapter 4 of Decision T 301/87 (OJ EPO 1990, 335) as well as in Chapter 3 of Decision T 19/90 (OJ EPO 1990, 476) imply that the respective Boards were satisfied that all variations comprised by the claims under consideration would - possibly with a few exceptions - give the desired result. Nothing else can be derived either from the corresponding reasoning in Decision T 60/89 (OJ EPO 1992, 268), points 2.2.2 to 2.2.7. of the reasons. In point 2 of the reasons of Decision T 182/89 (OJ EPO 1991, 391) the sufficiency of the disclosure was confirmed, since it was inter alia found that " there was no evidence or argument ... to suggest that a skilled reader of the patent would not be able to carry out the invention in any embodiment" (emphasis added). Decision T 212/88 (OJ EPO 1992, 28) concerns the repeatability of the worked examples. The question whether or not all products falling in the ambit of a "functional" definition could be obtained, was not at issue.

2.2.3. Therefore, in the Board's judgment there is no conflict between these decisions and Decision T 226/85 (OJ EPO 1988, 336), where it was held that the disclosure was insufficient, since the description did not contain adequate instructions which would allow the skilled person to perform random experiments with an acceptable statistical expectation of success (see points 7 and 8 and T 14/83, OJ EPO 1984, 105). On the contrary, these decisions are all based on the common ground that the disclosure of an invention is only sufficient if the skilled person can reasonably expect that substantially all embodiments of a claimed invention which this skilled person would envisage on the basis of the corresponding disclosure and the relevant common general knowledge can be put into practice. In other words, only exceptional failures can be tolerated. In the present case, however, the possibility of failure is far from being exceptional. Thus, the Respondent's submission that he is entitled to a broader protection because the knowledge of the disputed patent would provide an incentive for those skilled in the art to entertain further research activities which might lead to the discovery of further suitable compositions, has no basis in the EPC, nor is it supported by the cited jurisprudence of the Boards of Appeal.

3. First auxiliary request

3.1. The further definition of the "additive" according to Claim 1 of this request as a "hydrotrope" is supported by the patent specification, page 4, lines 60 to 64.

3.2. The above description indicates that some materials useful as hydrotropes in light-duty detergent compositions may behave as "additives". It is further stated that these are generally compounds having in their molecules a large polar group and, optionally, a small hydrophobic group. During the oral proceedings both parties agreed that for a person skilled in the art in the technical field of manufacturing detergent compositions the expression "hydrotrope" defines chemical compounds which increase the water-solubility of surfactants which are themselves not sufficiently soluble, and that this expression did not imply a particular chemical structure, although the most common products were urea, sodium toluene sulfonate, and ethanol. Therefore, the amended Claim 1 still seeks to define the "additive" by its desired activity rather than by structural parameters. Moreover, it is not stated that all compounds which a skilled person would envisage for use as "hydrotropes" were also suitable "additives" according to the present claim, but only some of them. Thus, even if the Board would admit, for sake of argument, that the open-ended expression "hydrotrope" would give the skilled person a useful hint as to which type of compounds might be suitable, it would still require a roving experimental search with a quite uncertain expectation of success to find suitable "hydrotropes" not belonging to the groups of compounds specifically mentioned in the patent as "additives". In other words, the disclosure is still not sufficient to ensure that, with an adequate statistical rate of success, the desired hexagonal liquid crystal phase will be obtained with the "additives" the skilled person would envisage according to the above definition.

Therefore, in respect of the disclosure of the invention defined by this claim, substantially the same considerations apply as for the invention defined by the claim according to the main request, i.e. that not all embodiments of the invention were, after reading the patent specification, at the disposal of the person skilled in the art. Consequently, this request must likewise fail.

4. Second auxiliary request

4.1. According to the sole claim of this request the definition of the "additive" is further limited to the group mentioned in the first sentence of point 3.2 above. This amendment is therefore not objectionable under Article 123 EPC, paragraphs (2) and (3).

4.2. The definition of the "additive" now contains not only the result to be achieved but, in addition, an indication of which structural requirements must be met in order to obtain this result. However, having regard to the fact that the Respondent was unable during the oral proceedings to indicate, on the basis of the patent specification, any other possibility for the skilled person to avoid failure in the attempt to carry out the invention than to use those "additives" which were specifically recommended therein, the situation remains substantially the same as that in respect of the first auxiliary request. The structural definition still comprises a practically unlimited number of individual compounds and the patent does not provide any guidance according to which a skilled person could identify the suitable individual compounds without undue effort. This identification would in the present case require him to establish for each individual compound in combination with a practically equally unlimited number of possible surfactant compositions (a) a complete phase diagram. However, the phase diagrams contained in the patent, which relate to the worked examples, in particular the comparison of Figures 1 to 5 (where the "additive" is urea) with Figure 6 (where the "additive is sodium toluene sulfonate), demonstrate that the area in which a hexagonal phase exists may become very small. In addition, the Respondent's assertion that, although the concentration range in which the desired hexagonal phase may exist varies unsystematically and thus unpredictably depending on the chemical structure of the components, the skilled person could still reasonably expect that with other suitable "additives" a hexagonal liquid crystal phase would be formed if concentrations similar to those corresponding to the "middle" of the area applicable for components according to the worked examples were chosen, is not supported by the above figures. Thus the person skilled in the art has no chance to perform some quick "screening" test in order to check whether an individual compound that meets the above broadly defined structural requirements will most likely force a mixture of a surfactant composition (a) and water into the desired hexagonal phase, if suitable concentrations are chosen. In the absence of such a possibility, the skilled person is in the present case confronted with the burden not only of selecting a suitable additive but also of choosing a corresponding surfactant composition and the suitable concentration, and yet he is provided with nothing more than a method to determine whether or not a certain individual composition is in the hexagonal liquid crystal phase. In addition, it follows from the figures mentioned above that in the present case the person skilled in the art cannot reasonably predict which "additives" with chemical structures considerably different from urea or sodium toluenesulfonate would be capable to force the surfactant compositions (a) of Claim 1 in the desired hexagonal liquid crystal phase, since the replacement of urea by sodium toluenesulfonate already strongly reduces the area in which such a phase exists. Thus the Board is still not satisfied that in respect of the present Claim 1 the skilled person is enabled by the description and the common general knowledge to conceive, with a reasonable expectation of success, suitable variants of the specifically described embodiments of the claimed invention.

For this reason the disclosure in the patent specification still remains insufficient in respect of most of the embodiments covered by the present Claim 1 and this request must also fail.

5. Third auxiliary request

5.1. According to the Respondent's submission the amendment which distinguishes the sole claim according to this request from the sole or first claims of the preceding requests finds its basis in the description as granted, page 5, lines 6 to 8 and lines 21 to 25. According to the disclosure page 5, lines 6 to 8 one preferred type of "additives" has the same or a similar polar head group as the surfactant a(i) but has a relatively small hydrocarbon chain containing at most 6 aliphatic carbon atoms. However, in the present Claim 1 the word "chain" was replaced by "group" in an attempt to extend the meaning of this expression in such a way that it covers compounds where the polar head group is not linked to an aliphatic but to an aromatic carbon atom, such as in toluene sulfonic acid. However, this amendment has no basis in the description as filed, which is, save a few clerical amendments, identical with the granted text. Therein, on page 5, line 2 to 4, it is stated that lower aryl or alkylaryl sulfonates, such as toluene and xylene sulfonates, may be used as "additives" for compositions based on detergent-chain-length alkylbenzene sulfonates. Thus the description as filed does not support the Respondent's submission that later on in the description the word "chain" has inadvertently been used where the use of the word "group" has been intended. Nor is there basis for the above amendment which creates a new sub- group or sub-generic definition of suitable "additives" which was not foreshadowed by the description as filed. Thus the subject-matter of the sole claim according to this request extends beyond the content of the application as filed, and does therefore not meet the requirement of Article 100(c) EPC. Consequently, this request must fail for this reason alone, so that there is no room for considering whether or not its subject- matter would have met the requirement of Art 100(b) EPC.

6. Fourth auxiliary request

6.1. Claim 1 of this request is based on Claims 1, 6, 7 and 9 as filed and granted in combination with the description as filed and granted (see page 5, lines 2 to 4 and lines 21 to 25 of the patent specification, which have already been discussed in respect of the third auxiliary request) and does not extend the scope of protection conferred by Claim 1 as granted. Therefore the amendment meets the requirements of Art 123(2) and (3) EPC.

6.2. According to the present Claim 1 the "additive" is selected from a limited list of individual chemical compounds which are structurally very similar to the "additives" used in the worked examples. Therefore, the "double burden" imposed on the skilled person by the broad and "functional" definitions of the suitable additives, namely to establish by trial and error which compounds are in principle suitable and at the same time to determine the suitable concentrations of all components of the compositions claimed according to the main and the first two auxiliary requests, no longer exists. It was not disputed by the Appellant that it is highly likely that for all "additives" now claimed a concentration range exists in which, depending on the chemical nature of the surfactant (a), a hexagonal liquid crystal phase is formed. In addition, having regard to the fact that the additives listed in the present Claim 1 which are not used in the examples are structurally very closely related to either urea or sodium toluene sulfonate, for which suitable concentration ranges can be derived from Figures 1 and 6, the exact determination of the concentration limits within which the desired hexagonal liquid crystal phase is formed when the other "additives" are used, cannot be regarded as an undue burden upon the skilled person. On the contrary, since he could reasonably expect that in these cases about the same concentrations will be applicable as those which are used in the above figures, only some routine experiments would be called for. Thus the Board holds that in respect of the subject-matter now claimed the requirement of Article 83 EPC is met and that, consequently, Article 100 b) EPC does not prejudice the maintenance of the disputed patent on the basis of the present Claim 1.

6.3. The Board is satisfied that the subject-matter of the present Claim 1 is novel. This was not disputed by the Appellant.

6.4. It remains to be decided whether or not the subject- matter of the present claim 1 involves an inventive step.

6.4.1. According to the printed patent specification detergent compositions in gel form were known at the priority date of the disputed patent. These gels were relatively soft gels based on lamellar phase liquid crystals. On the basis of this background art the technical problem derivable from the patent specification is to provide stable, transparent, translucent or opaque surfactant gels of high viscosity. Such gels are disclosed in document (2) which describes a transparent or translucent "liquid crystalline" plastic surfactant composition (column 1, lines 9 to 14). This plastic form is said to be comparable with the "middle phase" or "gum-soap" occurring in the manufacturing of sodium soaps of ordinary soap-making fatty acids (column 2, lines 1 to 44). Thus it was common ground between the parties in these appeal proceedings that the compositions described in document (2) were in the "hexagonal liquid crystal phase" as defined in the disputed patent. The known compositions contain a surfactant system which forms the desired gel phase spontaneously, see Example 5, column 6, line 50 to column 7, line 2. Having regard to this state of the art, the technical problem underlying the disputed patent can therefore be seen in providing further surfactant compositions in the form of a stiff gel as defined above.

6.4.2. The disputed patent essentially proposes to solve this problem by using a surfactant system (a) as defined in the present Claim 1, which differs from the surfactant used according to document (2) and which is not capable of forming the desired gel phase spontaneously, together with an "additive" (b) selected from the group indicated in the present Claim 1, which forces the surfactant system in the desired phase. Having regard to the worked examples the Board is satisfied that the above-defined technical problem has thereby been effectively solved.

6.4.3. Document (2) is silent about the possibility to force a surfactant composition in the desired gel form if this gel is not spontaneously formed. The disclosure of this document cannot therefore provide any hint of the above solution of the present technical problem. Document (1) relates to a detergent composition in liquid form, which may contain lower aliphatic alcohols and urea for the adjustment of the viscosity and the transparency (see Claims 1 and 4). The technical problem which this document sets out to solve is to produce liquid detergent compositions which are highly concentrated and remain stable and transparent at low temperatures. These compositions may further contain hydrotropic compounds such as xylenesulfonates in order to reduce the viscosity (page 11 of the description, lines 17 to 23). Thus this document teaches how to avoid a high viscosity of a detergent composition and a skilled person would not have considered this document when looking for further surfactant compositions in the form of a stiff gel. Document (3) was published after the priority date of the present patent and belongs to the state of the art which is excluded from consideration by virtue of Article 56 EPC, second sentence.

6.4.4. Thus the cited state of the art does not render the subject-matter of the present Claim 1 obvious to the person skilled in the art. The patent can therefore be maintained on the basis of that claim.

7. In these circumstances it is not necessary to consider the fifth auxiliary request.