Tuesday 20 December 2011

T 1789/09 – Margin Of Error


This decision – dealing with an opposition that had been rejected by the Opposition Division – contains some interesting statements on the scope of a claim the decisive parameter of which was affected by a considerable margin of error.

Claim 1 of the main request before the Board read:
A process for the preparation of a granular detergent composition or component having a bulk density greater than 650 g/l, which comprises the step of dispersing a liquid binder throughout a powder stream in a high speed mixer to form granular agglomerates,
characterised in that the powder stream comprises crystalline zeolite A having an oil absorbing capacity of at least 40ml/100g. (my emphasis)
In what follows, the Board dealt with the interpretation of the claim, sufficiency of disclosure and novelty:

Interpretation and sufficiency of disclosure (all requests)

[1.1] The objections made by the [opponent] with respect to sufficiency of disclosure are based on the [patent proprietor’s] interpretation of the parameter “oil absorbing capacity” used in Claim 1 of all requests.

[1.1.1] According to the [opponent] this term referred to the initial oil absorbing capacity of the zeolite before any process step was carried out. Otherwise, there would be a lack of sufficiency of disclosure since Claim 1 covered the possibility of forming powdery agglomerates of the zeolite with other components before the powder stream is introduced into the high speed mixer. The other components might change the oil absorbing capacity of the zeolite. However, it was impossible for any skilled person to measure the oil absorbing capacity of the zeolite within such agglomerates.

[1.1.2] In the [patent proprietor’s] opinion this interpretation was against the gist of the invention as set out in the patent. It was apparent from the description that the invention did not cover embodiments where the oil absorbing capacity of the zeolite would be lost by combining the zeolite with other components prior to introducing the zeolite containing material into the powder stream.

The [patent proprietor] pointed to the first sentence of paragraph 17 of the patent in suit where the following is stated:
“It is an essential feature of the present invention that the Zeolite A used in the formation of the granular agglomerates has an oil absorption capacity of at least 40ml/100g”,
and argued that following the second sentence of A 69(1), according to which the description had to be used for interpretation, Claim 1 had to be construed such that the zeolite had the oil absorbing capacity of at least 40 ml/100g at the moment where the liquid binder is dispersed within the high speed mixer throughout the powder stream.

[1.1.3] A 69(1) relates to the extent of protection conferred by a European patent or patent application. According to the Protocol on the Interpretation of A 69 which was adopted as an integral part of the EPC to provide a mechanism for harmonisation of the various national approaches to the interpretation and determination of the protection conferred by a patent, this should be done so as not to overestimate either the literal wording of the claims or the general inventive concept disclosed in the description (see also G 2/88 [2.1, 3.3 and 4]).

The Board notes, however, that this does not mean that the scope of protection conferred by a claim is generally limited by the description.

However, the sentence cited from paragraph 17 of the patent does not even say that the zeolite exhibits the oil absorbing capacity only during the formation of the granular agglomerates in the high speed mixer. In the Board’s opinion, the term “in the formation of” certainly covers the process of forming granular agglomerates as such, as it is expressed in Claim 1.

Moreover, since the process of Claim 1 merely “comprises” the step of dispersing a liquid binder throughout the zeolite containing powder stream in the high speed mixer, further process steps like formation of the powder stream by agglomeration with other ingredients are not excluded.

The [patent proprietor] has agreed that it would not be possible for a skilled person to measure the oil absorbing capacity of the zeolite within such agglomerates.

Hence, in the Board’s opinion, defining a process by a parameter which clearly cannot be measured does not make technical sense to the skilled artisan.

[1.1.4] The Board concludes therefore, that anyone skilled in the art would understand the oil absorbing capacity mentioned in the claims as that of the zeolite as initially applied, i.e. before any process step is carried out in the course of which the initial capacity is changed. No other meaning can be attributed to the term in question.

As a corollary to this conclusion, consideration of the [opponent’s] objection under A 83 is redundant.

[1.2] Another disagreement concerns the parties’ interpretation of the value of the oil absorbing capacity.

According to the patent in suit […], the oil absorption values can be determined by following British Standard Part 7: 1982 which corresponds to ISO 787/5-1980, i.e. document D1.

[1.2.1] The [opponent] argued that this standard included an inaccuracy of measurement of ± 50%.

[1.2.2] According to the [patent proprietor], however, the error was much smaller since document D1 only mentioned a difference of at most 50% between the absolute measured values. Further, this error did not even apply to zeolites since document D1 concerned pigments and extenders.

[1.2.3] In the Board’s opinion there is no reason to assume that the error is smaller with zeolites, since the patent recommends the standard of document D1 for determining the oil absorbing capacity and does not mention a particular accuracy especially if zeolites are used.

Concerning the extent of the error, it appears that the [patent proprietor’s] understanding is the correct one (see document D1, page 1, second paragraph). However, even in this case, the error is still as high as ± 33.33% (± 1/3).

Due to this uncertainty of measurement, the Board considers the values mentioned in the claims not as selective points but as ranges of possible values. Accordingly, the value of the oil absorbing capacity mentioned in Claim 1 of the main request covers the range of 40 ml/100g ± 33.33%, hence values from about 26.7 to 53.3 ml/100g.

Novelty (main request and first auxiliary request)

[2.1] Lack of novelty of the claimed subject-matter has been objected to, inter alia, in view of Example H of document D2.

[2.2] This example discloses a process wherein the spray-dried powder of Example G is granulated with liquid nonionic surfactant as binder in a Fukae high speed mixer to form a granular detergent agglomerate having a bulk density greater than 650 g/l (pages 8 to 10).

The powder stream of Example G comprises zeolite A, specifically Wessalith P ex Degussa […]. The oil absorbing capacity of Wessalith P as measured according to document D1 is given as 36 g/100g […] which translates into 39 ml/100g […] and with the inaccuracy of measurement of document D1 into the range of 26 to 52 ml/100g.

[2.3] The [patent proprietor] argued that the inaccuracy of measurement in document D2 was not comparable with that of the patent in suit since it was based on a sample of 100g instead of 5g as in document D1 and the patent.

[2.4] However, the Board adopts in this respect the [opponent’s] view that the accuracy of measurement rather increases with increasing sample size.

[2.5] Thus, there exists a large overlap between the oil absorbing capacity of 26.8 to 53.2 ml/100g of the zeolite A used in the process of Claim 1 of the main request and that of the Wessalith P of 26.13 to 51.87 ml/100g used in Example H of document D2.

Since there is no hint in document D2 not to work within the overlapping area, hence with zeolite A having an oil absorbing capacity of 26.8 to 51.87 ml/100g, the Board concludes that document D2 anticipates the process of Claim 1 of the main request.

[2.6] The same reasons apply mutatis mutandis to Claim 1 of the first auxilary request which differs from that of the main request only in that the oil absorbing capacity of zeolite A is now at least 45 ml/100g. As this value covers the range from 30 to 60 ml/100g, it still overlaps to a large extent with that of the Wessalith P used in document D2 […].

[2.9] For all these reasons, the Board concludes that the subject-matter of Claim 1 of the main request and the first auxiliary request is not novel in view of Example H of D2 (A 54).

Should you wish to download the whole decision, just click here.

The file wrapper can be found here.

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