Thursday, 26 January 2012

T 2020/07 – Official Selection

If the provisional results of the second poll are representative, there are quite a few chemists among the readers of this blog. Perhaps some of them might find the following decision interesting.

The patent proprietor filed an appeal against the decision of the Opposition Division revoking the opposed patent.

In what follows, the Board examined the novelty of the main request, claim 1 of which read (in English translation):
1. A process for the preparation of polyisobutenylphenol-containing Mannich adducts by
(a) alkylation of a phenol with polyisobutene having more than 70 mol% of vinylidene double bonds and a number average molecular weight of from 300 to 3000 at below about 50°C in the presence of an alkylation catalyst;
(b) reaction of the reaction product from a) with formaldehyde, an oligomer or a polymer of formaldehyde and at least one amine which has at least one secondary amino function and no primary amino function, or
(c) reaction of the reaction product from a) with at least one adduct of at least one amine which has at least one secondary or primary amino function and formaldehyde, an oligomer of formaldehyde, a polymer of formaldehyde or a formaldehyde equivalent,
wherein, in step (c), an adduct which is obtained from at least one amine and formaldehyde, an oligomer of formaldehyde, a polymer of formaldehyde or a formaldehyde equivalent by reacting the two reactants for at least 15 minutes at above +15°C is used and wherein this adduct is formed in the absence of the polyisobutenylphenol and only subsequently reacted with the polyisobutenylphenol.

*** Translation of the German original ***

[3.1] Document D1, which is to be taken into account as a prior, post-published European patent publication according to A 54(1), A 54(3) and A 89, discloses - in its claim 1 and under the chapter heading “Summary of the invention” on pages 1 and 2 – a composition comprising a Mannich adduct and an alcohol, as well as a process for producing this composition (claim 29). The Mannich adduct is “derived from” or produced from three components referred to as (A), (B), and (C) in the presence of alcohol, where (A) is a hydroxy containing aromatic compound having one to four hydrocarbyl groups of up to about 400 carbon atoms, (B) is an aldehyde or ketone having the formula R1-(CO)-R2 wherein R1 and R2 independently are H or hydrocarbyl groups having from 1 to about 18 carbon atoms and R2 can also contain carbonyl, and (C) is a mixture of water and an amine containing at least one primary or secondary amino group.

The description of D1 first deals with various embodiments of component (A), leading the reader from benzene or naphthalene nuclei […] having hydrocarbyl substituents (“R1”) and hydrocarbyl groups derived from an olefin to polyisobutene groups having a high content of methylvinylidene groups (e.g. based on “Ultravis 10” or “Ultravis 30” […]). “Ultravis 10” was used in part A of the only example of D1.

[…] Finally a polyisobutene-substituted phenol (PIB phenol) is referred to as preferred embodiment of component (A), wherein the polyisobutene substituent is derived from a polyisobutene (PIB) having a number average molecular weight (MN value) from about 300 to about 5000, or from about 500 to about 2500, respectively, and a minimum methylvinylidene isomer content of about 70%, e.g. about 80%.

Process step (a) of claim 1 of the present main request concerns the “alkylation of a phenol with polyisobutene having more than 70 mol% of vinylidene double bonds and a number average molecular weight of from 300 to 3000 …” Therefore, the PIB phenol produced in process step (a) of present claim 1 corresponds to the preferred embodiment of component (A) in D1.

[3.1.2] The description of component (B) in D1 also leads the reader from a general description of suitable substances, a great number of aldehydes and ketones, to a preferred embodiment. Lines 1 and 2 of page 6 refer to paraformaldehyde and “aqueous solutions of formalin (e. g., about 35 % to about 45 % by weight formalin in water) [as] preferred reactants.” In part B of the example of D1 paraformaldehyde was used.

Claim 1 of the present main request refers to the use of formaldehyde, an oligomer or a polymer of formaldehyde for both process variants. In […] the opposed patent, these terms are explained in more detail: they comprise the terms formalin solution, trioxane and paraformaldehyde. In this case also the used compounds are partially identical with those of D1.

[3.1.3] According to claim 1 of D1, a mixture of water and an amine containing at least one primary or secondary amino group is used as component (C). Starting from line 4 of page 6, the amine component is explained in more detail. Accordingly, it typically contains a certain amount of water (“The weight ratio of amine to water is typically about 50:50 to about 99:1”) and, therefore, has two components. The amine contained therein shall contain at least one group referred to as “> NH”. In a list of suitable amines of different structure […], wherein ethylene diamine is referred to as a “preferred amine” […] the last paragraph of page 6 also mentions amines having a secondary and no primary amino group: dimethylamine, N-methyl-ethylamine, N-methyl- octylamine, and dibutylamine.

Those last-mentioned amines in the list of exemplary amines of D1, therefore, fulfil the requirements of amines according to variant (b) of claim 1 of the present main request: at least one secondary amine group but no primary amino function.

[3.1.4] Claim 1 of document D1 only recites the substances that are initially contained in the reaction mixture (i.e. the components (A), (B), and (C) according to their most general definitions) but does not provide any features of the process for producing the Mannich adduct. Process claim 29 only requires component (A) to be reacted with components (B) and (C) in the presence of alcohol. Dependent claim 33 mentions a range from 40 to 200°C as process temperature. Claim 34 concerns a process wherein the polyisobutene substituent is derived from a polyisobutene having a methylvinylidene isomer content of at least about 70%, paraformaldehyde and a mixture of water and ethylene diamine, and which is carried out in the presence of 2-ethyl hexanol. There is only one place in the description of D1 where the process for producing the claimed compound is explained in more detail – in view of the process features defined in the present claims of the opposed patent – than in these process claims: in the only example on pages 11 and 12 of D1.

[3.1.5] There was agreement between the parties that the first process step (a) according to claim 1 of the present main request did not differ from part A of the example of D1, not even in view of the temperatures used. However, the [patent proprietor] had based its argumentation that in part B of the example of D1, which describes the subsequent Mannich reaction of the PIB phenol of part A, 2-ethyl hexanol and water were present, whereas none of these compounds is added according to claim 1 of the main request.

[3.1.6] In view of this argument [the Board] refers to the different embodiments of variant (i) in the examples IIb, IIe and IIf […] of the opposed patent. For instance, in example IIb, as also explained in general terms in paragraph [0068], an alcohol, i.e. isopropanol, is added. On the other hand, in examples IIa and IIe, a 37% strength formalin solution is used, and in example IIf a “37% strength aqueous solution of formaldehyde” is expressly added to the present components PIB phenol and dimethylamine (“40 ml of 40% strength aqueous solution”). There the reaction mixture, therefore, apparently contains the very components that are described in claim 1 of D1. For the sake of completeness, [the Board] notes that in example 3 of the trial report of the patent proprietor dated July 13, 2007, water and formaldehyde were also added.

Moreover, water is formed during the Mannich reaction, as can be seen from part B of the example of D1 and also the last reaction formula on page 261 of D9.

Considering these findings, the argument of the [patent proprietor] concerning the addition of water or alcohol, respectively, in D1, in order to establish differences that are relevant for the decision on novelty, is not persuasive.

[3.2] The example in D1 and the parts of its general disclosure mentioned above show that the use of PIB phenol having a MN value within the range from 300 to 2500 and a methylvinylidene content close to or above 70 % (i.e. within the definition of the opposed patent) and of formaldehyde in various common embodiments (Einsatzformen), i.e. as (polymer) paraformaldehyde or as aqueous formaldehyde solution, respectively, is also generally preferred in D1. Therefore, there is only one significant difference between this preferred embodiment of D1, the example, and the subject-matter of the opposed patent, i.e. the selection of an amine other than ethylenediamine.

[3.2.1] As already mentioned in paragraph [3.1.3] above, at the beginning of the first group of the amines that are expressly listed in D1 […] four secondary amines are listed as examples for “primary or secondary amines” as closest alternatives following methylamine: dimethylamine, N-methyl-ethylamine, N-methyl-octylamine, and dibutylamine.

[3.2.2] The Board is of the opinion that such a replacement of a component (of a primary amine) by a compound that is disclosed as a simple alternative (a secondary amine) wherein all the other preferred components of the disclosure are maintained, cannot lead to the acknowledgement of novelty.

[3.2.3] As neither the general description nor the example of D1 suggests the replacement of the preferred PIB phenol or of the preferred aldehyde, but the amine used in the example of D1 is not the but just one preferred amine, the present situation is quite close to the one of decision T 332/87 [2.2, 2nd §] :
“This means that, when examining novelty, different passages of one document may be combined provided that there are no reasons which would prevent a skilled person from such a combination. In general the technical teaching of examples may be combined with that disclosed elsewhere in the same document, e.g. in the description of a patent document, provided that the example concerned is indeed representative for the general technical teaching disclosed in the respective document.”
The finding of paragraph [3.2.2] above is supported even more strongly by decision T 278/97 [] where a disclaimer that had been introduced in claim 1 of the patent under consideration, which excluded a certain support material (cellulose triacetate) was considered to be insufficient for distinguishing [the claimed subject-matter] over a patent application to be considered under A 54(3) and, therefore, for establishing novelty. The prior application (document D4) contained an example 4, wherein cellulose triacetate was used as support material. This example destroyed the novelty of claim 1 under consideration. In the general description there was an explicit list of possible carriers, and this list also mentioned cellulose triacetate. The Board explained that the document did not give any reasons hindering the skilled person from using such a different support. It rather taught that this different support could be used instead of cellulose triacetate.

[3.3] In view of these facts and findings, the Board has arrived at the conclusion that in the present case claim 1 of the main request (and, therefore, the entire main request) cannot be acknowledged to be novel over D1 (A 54(1) and 54(3)).

NB: This decision has more to offer, as we shall see in a forthcoming post.

Should you wish to download the whole decision (in German), just click here.

The file wrapper can be found here.