T 0116/99 (Hydroxyalkyl substituted amine/CHEVRON) 18-10-2001

1. Procedural issues

1.1. The Respondent filed auxiliary requests B, C and D with a letter dated 18 September 2001, i.e. one month before oral proceedings.

These requests are thus late filed.

As the Respondent argued, auxiliary requests B, C and D had been filed as a precaution against a possible finding of lack of novelty and/or of inventive step in view of the experimental report filed by Appellant 01 with a letter dated 11 September 2001 as further support to the objections already raised in the grounds of appeal.

In the Board's view all the amendments contained in these requests were easily understandable and amounted to a limitation to embodiments already contained in the original claims. Moreover none of these amendments led to a substantial change in the subject-matter of the proceedings, which would have needed ample reconsiderations by the Appellants.

Therefore, the Board finds that these requests, even though late filed, amounted to a fair attempt by the Respondent to defend its patent and did not delay the proceedings.

Accordingly, the Board has admitted these requests.

2. Article 123(3) EPC

2.1. In each of the requests in question, Claim 1 differs from Claim 1 as granted inter alia insofar by no longer relating to a deposit control additive comprising the specified hydroxyalkyl substituted amine and a carrier oil, but to a fuel composition comprising a major amount of hydrocarbons boiling in the gasoline or diesel range and a minor amount of the previously mentioned additive.

Since a claim to a product "per se" gives absolute protection for the claimed product (see G 2/88, OJ EPO 1990, 93, point 5 of the reasons for the decision), the scope of the claim as granted also encompassed all compositions comprising this deposit control additive. Therefore, the scope of a claim directed to a fuel composition comprising such an additive is necessarily narrower than that of the original additive claim and this amendment cannot contravene the requirements of Article 123(3) EPC.

One of the Appellants argued that the fuel composition had to be construed as relating to a composition comprising the listed components independently from their provenance, e.g. deriving from the deposit control additive or from other sources. Therefore these claims extended to compositions prepared by adding, separately, a deposit control additive not comprising a carrier oil and a different oil source to a fuel, i.e. they encompassed an invention which was not covered by the scope of the granted claims.

It is, however, established jurisprudence of the Boards of Appeal that, following the provisions of Article 69(1) EPC and its Protocol on Interpretation, the scope of a claim must be assessed taking into account not only the claims but also the description and any drawings (see G 2/88, OJ EPO 1990, 93, point 4 of the reasons for the decision). The skilled person would therefore readily understand by reading the patent in suit that the mentioned carrier oil has to be added as a carrier for the hydroxyalkyl substituted amine in the deposit control additive (see page 6, line 45).

Therefore it is the Board's finding that, on a fair reading of the description, the theoretical situation described by the Appellant is not contemplated by the invention of the patent in suit.

Therefore, Claim 1 according to all requests complies with the requirements of Article 123(3) EPC.

3. Main Request

3.1. Novelty

3.1.1. According to the established jurisprudence of the Boards of Appeal, a prior art disclosure is novelty destroying if it discloses directly and unambiguously the subject-matter in question when also taking account of everything which would be considered by a skilled person as part of the common general knowledge in connection with the disclosed subject-matter at the publication date of the cited document in case of prior art cited under Article 54(2) EPC, or at the priority date of the cited document in case of an Article 54(3) document (see Case Law of the Boards of Appeal of the EPO, 3rd ed., 1998, page 74, point 4).

3.1.2. In the present case document (1) had been cited against the novelty of the subject-matter of Claim 1 under Article 54(3) EPC. All parties agreed that this document explicitly discloses a fuel composition comprising a hydroxyalkyl substituted amine of the type used in the patent in suit, which amine can be used in amounts of 50 to 5000 ppm in a fuel (page 4, lines 4 to 5); however, it does not explicitly disclose the use of a carrier oil in combination with such an amine.

The Appellants referred to various documents in order to show that it was common general knowledge to use a carrier oil in combination with such amines at the priority date of the cited document. Indeed, these documents teach that the use of a carrier oil together with amines of the polybuteneamine class leads to advantages with respect to their cleaning performance.

For example, document (25) teaches that second-generation detergents, e.g., polyisobutenamines, are frequently used in combination with very thermally stable carrier oils that keep the surface of the valve lubricated and ensure continuous flowing off of deposit particles, and that relatively high concentrations of detergent and carrier oils are used to keep inlet valves clean, and indeed many suppliers provide additive packages with a claimed effectiveness over the entire inlet system (page 735, left column, lines 30 to 37 and 41 to 45 and passage bridging left and right columns).

Document (18) teaches on pages 32 and 33 that it is customary to combine polymeric inlet valve deposit control additives such as the polybutene amines with petroleum-based or thermally-stable synthetic oils known as fluidizers, carrier oils or solvent oils. These additives are added to a fuel at higher concentrations than conventional amine detergents and fluidizers or solvents may also be added resulting in a multi-functional additive package.

Finally, document (5) teaches that fuel additive packages comprise detergents and carrier oils (page 5) and that carrier oils are used to support the detergent action of e.g. additives like polybutene amines (page 13).

However, none of these documents suggests that such an oil would have been inevitably used by the skilled person at the priority date of document (1), i.e. independently from the amount of additive used and with any type of amine, e.g. also with substituted amines as used in the patent in suit. It is thus the Board's view that document (1) does not contain any explicit or implicit teaching that a carrier oil should inevitably be used.

3.1.3. One of the Appellants also filed an experimental report in order to show that it was not possible to carry out a motor test with the hydroxyalkyl substituted amines of document (1) or with the amines of document (8) in the absence of a carrier oil; therefore a carrier oil must have also been used in document (1). However, the only conclusion which can be drawn from these tests is that the skilled person would have not been able to use the additives of document (1) in a motor test without a carrier oil under the specific conditions used in such tests. That does not mean that a carrier oil should inevitably be used for performing the invention of document (1) or that the disclosure of document (1) contains a pointer to the use of a carrier oil.

Therefore, in the Board's finding the subject-matter of Claim 1 has to be regarded as being novel.

Furthermore, and as not contested by the Appellants, the prior art does not disclose an additive concentrate as in Claim 4 of the patent in suit, which therefore also complies with the requirements of Article 54 EPC.

3.2. Inventive step

3.2.1. Closest prior art and technical problem

The patent in suit and in particular the subject-matter of Claim 1 of the main request relates to a fuel composition comprising a deposit control additive comprising a hydroxyalkyl substituted amine and a carrier oil, the amine being the reaction product of a polyolefin epoxide derived from a branched chain polyolefin having an average molecular weight of 400 to 5000 and a nitrogen-containing compound selected from ammonia, a monoamine having from 1 to 40 carbon atoms, and a polyamine having from 2 to 12 amine nitrogen atoms and from 2 to 40 carbon atoms (page 2, lines 48 to 53).

As explained in the patent in suit, deposit control additives were used in a fuel for reducing deposit formation on different parts of an internal combustion engine, e.g. the intake valves. However, an inconvenience of the methods of manufacturing the prior art additives, e.g. of the polybutenamines, was the presence of residual chlorine in the final product, which had an undesirable impact on the emissions produced by the combustion process (page 2, lines 1 to 13).

As suggested by the parties, the Board takes document (8), which appears to be representative for the state of the art addressed in the patent in suit, as the starting point for evaluating inventive step.

Document (8) discloses polyisobutenamine derivatives prepared without using halogenated reactants and being suitable additives for fuel in order to provide reduced deposit formation on the intake valves (see column 1, lines 35 to 59; column 3, lines 1 to 34; column 4, lines 16 to 25 and column 5, lines 35 to 61).

These additives differ from those used in the patent in suit insofar as they contain a hydroxyl on the polar alkyl amino group and not on the polymeric alkyl chain in -position to the amino group and insofar as the polyisobutylene chain is connected to the amino group via an additional methylene group deriving from the hydroformylation step; they comply with the general formula

FORMULA

wherein R1 is a polyisobutylene having an average molecular weight of 500 to 1500 and R2 and R3 may be a hydroxyalkyl group, e.g. an ethyl alcohol group.

The compounds of the patent in suit may instead be represented by the general formulae reported in document (1), i.e. by

FORMULA

and

FORMULA

wherein R represents a polyisobutylene group having an average molecular weight of 400 to 5000 and one of X is a hydroxy group and the other one an optionally substituted amino group.

No credible technical advantage over the closest compounds of document (8) has been established by the Respondent.

In particular the experimental report filed by the Respondent with its letter of 18 September 2001 compares an amine according to Example 2 of document (1), i.e. the reaction product of a polyisobutenepoxide and a diethylenetriamine, with a compound prepared as in document (8) by hydroformylation of a reactive polyisobutene and subsequent reductive amination with ammonia.

However, the Board considers that these comparative tests should have been carried out with respect to a compound having an alkyl amino group bearing also a hydroxyl substituent, as also preferred in document (8) in the case of fuel additives (column 3, lines 1 to 28, in particular the formulae between lines 20 and 25, and column 5, lines 59 to 61), and not with respect to a product derived from a reaction with ammonia (see T 181/82, OJ EPO, 1984, 401, point 5 of the reasons for the decision).

The results of the Respondent's tests are thus not directly comparable, since they have not been carried out with respect to the closest compound of the prior art; they cannot therefore prove any advantage with respect to the closest prior art.

Finally, the comparative tests contained in the patent in suit cannot prove any advantage either. In fact, they compare a commercial product, which according to the Respondent was a commercially available reaction product of polyisobutylamine and diethyleneamine, with either compounds of the patent in suit having different polar groups (Examples 3 to 6), which results are thus not directly comparable; or with a similar product of the invention (Example 7). This Example 7 however shows, if anything, a similar result to the commercial product tests, and presents no comparison with the closest prior art, i.e. the closest compound of document (8) mentioned above.

Therefore no unexpected superior technical advantage with respect to the closest prior art has been proved by the Respondent.

The technical problem solved by the patent in suit and deducible from it was therefore simply the provision of further fuels containing no residual chlorine and thus of alternative amine additives, prepared in such a way as not to contain residual chlorine and providing a reduction of the deposit formation on intake valves comparable with that of the prior art (page 2, lines 14 to 16 and 46 to 47).

The Board has no reason to doubt that the subject-matter of claim 1 solved this existing technical problem, nor was this disputed by the Appellants.

3.2.2. Evaluation of inventive step

A skilled person, faced with the technical problem mentioned above, would have looked for other polyisobutylenamines similar to those of document (8) as fuel additives, also prepared by a method not leading to the formation of residual chlorine in the additive.

In the Board's view, moreover, a slight structural modification of a known compound, e.g. a monoamine or a polyamine known from document (8), cannot be considered to involve an inventive step, if the preparation of such a similar compound was known to the skilled person and its use does not lead to an unexpected superior technical advantage with respect to the closest prior art (see T 939/92, OJ EPO 1996, 309; points 2.5.3 and 2.6.2 of the reasons for the decision), which closest prior art is represented by the similar compound of document (8) having an amino group bearing a hydroxyl residue.

As shown above under point 3.2.1 a superior technical advantage has not been proved.

In this respect the Respondent argued that the effect obtainable by a similar but structurally different compound was unpredictable and therefore the skilled person could not have known whether a compound was suitable or not as a fuel additive before having tried it.

However, the effect brought about by the polyisobutenamines which, as admitted by all parties, were known fuel additives having a "clean-up" and "keep-clean" effect, derives from their structural detergent configuration, consisting of a long oleophilic chain and a polar hydrophilic group, as supported by the prior art teaching (see document (5), page 5, the paragraph below Figure 1 and document (16), passages bridging pages 72 and 73 and left and right column on page 73, respectively). Therefore, the presence either of an additional methylene group between the polyolefin chain and the amino group (which in fact means only that the long chain hydrocarbon residue is extended by one further -CH2- group) or of a hydroxyl on the alkyl amino group instead of on the polymeric alkyl chain in -position to the amino group would be considered by the skilled person as having no appreciable influence on the detergent properties of the respective compounds. A skilled person would thus not have expected such structural change to bring about any noteworthy change in the ability to dissolve greasy rests and keep particles in suspension.

A skilled person, looking for other compounds similar to those of document (8) and prepared by a method not leading to the formation of residual chlorine, would thus have promptly recognised that document (2) already disclosed polyisobutylamines having cleaning and dispersing properties prepared by a method analogous to that of the patent in suit, which amines therefore must have an identical structure (see column 2, lines 1 to 70; column 3, lines 43 to 52 and Examples 1, 3 and 4). Even if these amines were used according to the teaching of document (2) as additives for a motor oil, the skilled person would have expected these compounds to be applicable as cleaning and dispersing additives in a fuel because of their structural similarity to those of the compounds of document (8) and to the known general class of polybutenamine fuel additives.

Consequently, it is the Board's finding that the subject-matter of Claim 1 of the main request does not involve an inventive step.

4. Auxiliary requests B, C and D

4.1. Novelty

The auxiliary request B differed from the main request insofar as the fuel-soluble, nonvolatile carrier oil of Claim 1 was specified to be selected from a lubricating mineral oil; and poly(oxyalkylene) alcohols, glycols and polyols or mixtures thereof.

The auxiliary request C differed from the main request insofar as Claims 1 and 4 specified that the polyolefin epoxide was derived from a polyisobutene and the nitrogen containing compound was limited to ammonia or a monoamine having from 1 to 40 carbon atoms.

The auxiliary request D differed from auxiliary request C insofar as Claim 1 contained the same limitation with respect to the fuel-soluble nonvolatile carrier oil contained in auxiliary request B.

Since the subject-matter of Claims 1 and 4 of the main request have been found to be novel, the more restricted claims of these requests must be novel too.

4.2. Inventive step

None of the additional features of the auxiliary requests B, C and D contribute in any way to providing greater efficiency of the claimed fuel or additive as the Respondent admitted at the oral proceedings. Therefore, they cannot support the presence of an inventive step and the reasons put forward in paragraph 3.2.2. above apply equally to these requests.

Therefore, these requests must also be dismissed for lack of inventive step of the claimed subject-matter.