Thursday, 12 January 2012

T 520/06 – Walk The Line

Opponent 3 filed an appeal after the Opposition Division (OD) had rejected the opposition.

Claim 1 before the Board (which corresponds to claim 1 as granted) read:
A precipitated silica characterised in that it has:
  • a CTAB specific surface area (SCTAB) of between 140 and 240 m2/g,
  • a porous distribution such that the porous volume formed by pores whose diameter is between 175 and 275 Å represents less than 50% of the porous volume formed by pores of diameters less than or equal to 400 Å,
  • an ultrasound disagglomeration factor (FD) of higher than 5.5 ml, and
  • a median diameter (Ø50) after ultrasound disagglomeration of less than 5 μm,
and is in at least one of the following forms: substantially spherical balls of a mean size of at least 80 μm, powder of a mean size of at least 15 μm and granules of a size of at least 1 mm.
and independent process claim 6 read:
A process for the preparation of a silica according to one of claims 1 to 5 comprising the reaction of an alkali metal silicate M with an acidifying agent, thereby obtaining a precipitated silica suspension, then separation and drying of said suspension, characterised by effecting precipitation in the following manner:
(i) forming an initial vessel bottoms comprising a part of the total amount of the alkali metal silicate M involved in the reaction, the concentration of silicate (expressed as SO2) in said vessel bottoms being at most 15 g/l,
(ii) adding the acidifying agent to said initial vessel bottoms until at least 50% of the amount of M20 present in said initial vessel bottoms is neutralised, and
(iii) simultaneously adding to the reaction medium acidifying agent and the remaining amount of alkali metal silicate M such that the ratio of the amount of silicate added (expressed as Si02)/amount of silicate present in the initial vessel bottoms (expressed as Si02) is between 12 and 100.
Among other things, the Board dealt with the objections that claim 6 did violate A 123(2) and that claim 1 was not novel:

*** Translation of the French original ***

[2.1] Process claim 6 is based on process claims 1 to 3 of the application as filed. However, the initial silicate concentration […] according to claim 6 of the patent is limited to “at most 15 g/l” whereas the independent process claim 1 of the application as filed only requires a value “less than 20 g/l”.

[2.2] In application of the principle restated in T 925/98 [2] the Board considers that a limiting amendment consisting in a replacement of the upper limit “less than 20 g/l” of said range by the limit “at most 15 g/l” does not extend the subject-matter of claim 6 beyond the content of the application as filed.

[2.2.1] In the present case, the value of the upper limit of a narrow preferred range (“between 10 and 15 g/l; cf. claim 11 of the application as filed) is used to delimit the more general range which has an upper limit of 20 g/l (cf. claim 1 of the application as filed) but which is not limited by a precise value at its lower end.

[2.2.2] It has been submitted that the principle restated in T 925/98 does not apply to the present case. It is not obvious to the Board why this principle would not be applicable to the particular case of a larger range of values corresponding to an open interval, i.e. which has been formulated without any indication of a precise value for one of the two boundaries of said interval. […]

[9] Document D2, which was cited as a novelty-destructive document, discloses the preparation of precipitated silica and their use as reinforcing filler for elastomers […]. According to D2, said silica are easily dispersed and have improved reinforcing properties. They are obtained by reacting silicate with an acidifying agent and have granular, powder or bead shape.

[9.1] Generally speaking, the precipitated silica disclosed in document D2 have a specific surface area SCTAB between 140 and 200 m2/g […]. The granules preferably have a dimension between 1 and 10 mm […]. The powders generally have an average granulometry (D50) of between 5 and 70 μm, preferably between 10 and 30 μm […] and the beads have an average size of at least 80 μm […]. The powders and the beads according to D2 preferably have an ultrasound disagglomeration factor that is greater than 6 ml or 5.5 ml, respectively […] and have a median diameter (Ø50) after ultrasound disagglomeration of less than 4.5 μm or 5 μm, respectively […]. As far as the above cited parameters are concerned, the silica disclosed in D2 comply with the criteria mentioned in claim 1 of the opposed patent.

[9.2] However, the precipitated silica according to D2 are characterised by a very particular distribution of their porous volume, this distribution being expressed by means of the ratio (in %) between the porous volume constituted by the pores having a diameter between 175 Å and 275 Å and the porous volume constituted by the pores having diameters of less than or equal to 400 Å, this ratio being referred to as “V2/V1” […]. Said ratio V2/V1 is of at least 60%, preferably of at least 65%, for granules, and of at least 50%, preferably of at least 60%, for powders and beads.

[10] Now, the Board is of the opinion that the claim feature of the patent under consideration regarding the distribution of porous volume, which can be expressed in the form of the condition that V2/V1 < 50% limits claim 1 to silica which the skilled person can distinguish from silica having a ration V2/V1 of 50% or more by means of measurement according to the method cited in the patent under consideration (mercury porosimetry) […], which by the way is the same as the one in D2 […]. 

[11] Contrary to the opinion of the [opponent], claim 1 of the patent under consideration unambiguously excludes the products disclosed by D2 […], i.e. precipitated silica having powder or bead shape and a V2/V1 ratio ≥ 50% as well as granules having a ratio V2/V1 ≥ 60% and the silica according to example 12 of D2 where the V2/V1 ratio is equal to 61%. 

[12] It has to be noted that D2 also discloses comparative products having a V2/V1 ratio that is clearly smaller than 50% (cf. table I and example 2; PC1: 43%; PC2: 46%). Products PC1 (Ø50: 7.4 μm, FD: 3.0 ml) and PC2 (Ø50: 9.9 μm, FD: 2.3 ml) however, do not comply with the criteria given in claim 1 of the patent under consideration according to which Ø50 < 5 μm and FD > 5.5. The V2/V1 value of the comparative products GRC1 and GRC2 mentioned in D2 (53% […]) is greater than 50% and its Ø50 and FD values are not given.

The smallest V2/V1 value given for a non-comparative product according to D2 is 57% […].

[13] Therefore, all the precipitated silica disclosed in D2, including the ones disclosed as comparative products, differ from the silica according to claim 1 of the patent under consideration at least regarding the distribution of their porous volume (according to the teaching of D2) and/or regarding the values for Ø50 and FD (comparative products in D2).

[14] In particular, the beads according to example 12 of D2 (comparative product MP1 according to the opposed patent) have a V2/V1 ratio (61%) that is greater than 50% and, therefore, are perfectly distinguishable from the claimed beads. This conclusion is not liable to be called into question in view of documents E2 and E4 which essentially only deal with the influence the sampling conditions can have on the results obtained when the V2/V1 values of granules are measured.

[15] As regards the decisions cited by the [opponent], the Board notes that they are not directly applicable to the present case, for the following reasons:

[15.1] The principle developed in decision T 594/01 [4.1.5] cannot be applied to the present case, be it only because the value of 50% mentioned several times in D2 is not an “experimental value” that has been concretely measured on an embodiment, but the lower boundary defining the range of V2/V1 values to be complied with (à respecter) according to D2. None of the examples of embodiments of D2 discloses a value equal to or even close to 50%, the smallest experimental value disclosed being equal to 57% […]. The V2/V1 values smaller than 50% mentioned in D2 (tables I and II) only concern the comparative products (“PC1” and “PC2”) and do not disclose the whole set of features of the product according to claim 1 of the patent under consideration […].

[15.1.1] According to the established case law of the Boards of appeal, including decision T 240/95 [4.2, 3rd §], a numerical range expressed as “from x to y” effectively constitutes a disclosure of the numerical values x and y. However, in the case of the patent under consideration, the range of claim 1 under consideration is formulated as an open interval having an upper boundary, i.e. “less than 50%”. This wording expressly excludes the value of 50%.

[15.1.2] Decision T 666/89 concerns situations of “selection” and “overlapping” of numerical ranges. However, in the present case, the respective ranges for the V2/V1 parameter in D2 and in the patent under consideration precisely do not overlap, because the interval defined by the expression “< 50%” does not have any point in common with the interval defined by the expression “≥ 50%”.

[15.1.3] Therefore, considering said decisions does not lead to a different assessment of D2 than the one given in points [13] and [14] above.

The claims were found to be novel and inventive.

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

The file wrapper can be found here.