I find this case interesting because the applicant found a clever way to overcome a novelty objection; unfortunately, this goal was achieved by using an effect that turned out to be an obvious bonus effect. Therefore, the claim finally fell for lack of inventive step. However, the strategy chosen could be salutary when the novelty destroying prior art is an A 54(3) document.
Claim 1 of the main request read:
A method for preparing a glass composition, said method comprising forming a batch of glass-forming components by admixing a volatile component source containing a volatile selected from the group consisting of boron and heavy metals; a silicate compound of the formula KuNavAlwCaxMgySiOz wherein […] u, v and w, independently range from about 0 to about 0.5; x and y […] from about 0.1 to about 0.6; and z is a value which balances the formula; and other glass-forming components; melting and refining the batch of glass-forming components in a furnace the resultant melt to obtain a glass composition; wherein said glass composition has a reduced variability of oxides distribution measured at the feed end of said furnace or a reduced loss of said volatile component than a glass composition having an equivalent composition produced without using said silicate compound.
[…] D1 discloses in combination all the features of claim 1 [of] the main request. It is true that diopside is added as a colourant for producing a stained, emerald-green or bluish-green glass and that no reference to refining aids or the volatility of components in the melting process is made. However, on the principle that the same causes must give rise to the same effects, diopside will effectively act in the same way as claimed in the present application, i.e., it reduces melt viscosity, loss of volatiles and variability of oxides distribution, irrespective of whether or not said effects are explicitly taught in D1.
[Claim 1 of] the main request therefore lacks novelty (A 54(1)(2)). The main request is not allowable. [1.1]
The auxiliary request was designed to overcome the novelty objection via the ‘novelty of use’ doctrine. Claim 1 of this request read:
Use of a silicate compound of the formula KuNavAlwCaxMgySiOz wherein […] u, v and w, independently range from about 0 to about 0.5; x and y independently range from about 0.1 to about 0.6; and z is a value which balances the formula; in a method for preparing a glass composition, said method comprising forming a batch of glass-forming components by admixing the said silicate; a volatile component source containing a volatile selected from the group consisting of boron and heavy metals; and other glass-forming components; melting and refining the batch of glass-forming components in a furnace to obtain a glass composition; wherein use of the said silicate provides a reduced loss of said volatile component from the said glass composition than from a glass composition having an equivalent composition produced without using said silicate compound.
The subject matter of the claims in accordance with the auxiliary request relates to a second non-medical use. Since none of the available prior art documents discloses the effect of reducing the loss of volatile components from the glass composition, as stated in the claim, it may thus be considered a novelty-imparting technical feature within the meaning of decision G 2/88 [10.3]. The subject matter of claim 1 of the auxiliary request meets the requirements of A 54(1)(2). [1.2]
The board considers document D3 to represent the closest prior art because it is concerned with a similar objective as the present application, that is, improving batch uniformity, reducing fining time, shortening melting times, etc. According to D3, these and other advantages are achieved by adding to the glass composition a silicate material comprising one or more compounds selected from calcium silicates, magnesium silicates and calcium magnesium silicates. A preferred silicate material is diopside (CaMg(SiO3)2).
As advantageous effects of adding the silicate material to a glass batch, D3 explicitly mentions a better heat transfer, a lower fining time due to 30% to 40% less gas, and shorter melting times. D3 does not, however, teach reduced loss of volatiles. [2.1]
In the light of the teaching of document D3, the technical problem underlying the application in suit therefore consists in reducing the loss of volatile components, selected from boron and heavy metals, from a glass composition during the melting operation. [2.2]
As a solution to this problem the application in suit proposes the use of a silicate additive according to the formula of claim 1 in a method comprising forming a batch of glass-forming components and refining the batch characterized in that the use of said silicate provides a reduced loss of volatiles. [2.3]
The claimed use encompasses the formation of molten glass batches of any kind and composition, using a broad class of volatile component sources (boron and heavy metals). The desired reduction in volatile loss has been made plausible only for one particular glass melt. Moreover, the desired better homogeneity and reduced variability of oxides has been asserted only in a qualitative and indirect manner. It appears implausible to the board that addition of a silicate compound as claimed may effectively reduce melt viscosity and melt temperature in essentially all conceivable glass melts, irrespective of their compositions. Although it is thus questionable whether the above stated technical problem has indeed been solved over the whole ambit of the claim, the board will assume, in favour of the appellant, that this is the case. [2.4]
It remains to be decided whether or not the claimed solution is obvious having regard to the prior art.
As mentioned above, D3 already teaches the use of additives (e.g. diopside) for better heat transfer, lower fining time and shorter melting times. Evidently, a lower fining time and a shorter melting time both tend to reduce the total loss of volatiles because said loss depends - apart from on the melt temperature - also on the total time required for melting the glass components and fining the glass batch. The person skilled in the art of glass making, confronted with the above defined technical problem, would thus have recognised that the diopside additive proposed in D3 exhibits, as an additional advantage, the effect of reducing the loss of volatiles. Diopside according to document D3 satisfies the formula of the silicate compound in claim 1 of the auxiliary request. The reduction of total loss of volatiles is a collateral effect which has been identified by the applicant. The identification of this effect however does not require any ingenuity. [2.5]
Therefore, the use as defined in claim 1 in accordance with the auxiliary request does not involve an inventive step as required by A 56. The auxiliary request is therefore also not allowable. [2.6]
I have always thought that the Enlarged Board of Appeal had a bad day when it issued decisions G 2/88 and G 6/88, but now that we have them, why not make use of them?
To read the whole decision, click here.
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