T 0355/22 - Amending to restore inventive step

Key points

•  The proprietor restores inventive step by adding a feature to claim 1 that is already taught in the closest prior art.
• This would be an interesting thing to test on the (new) EQE.
• "D9 also relates to carbon-based additives for lead-acid batteries (paragraphs [0001] and [0011]) and is a suitable starting point for assessing inventive step."
• "The opponent is of the view that the objective technical problem is merely providing an alternative because oxidized carbon black "A" ([(] Table 1 of the contested patent) showed comparable performance with the control carbon black "CB" (Table 4 and Figure 4) "
• The Board:"Oxidized carbon black "A" is not encompassed by claim 1 because the volatile content is slightly below the claimed range of at least 5.5 wt.%. The observation that oxidized carbon black "A" does not solve the technical problem posed in this case nevertheless leads to the conclusion that the technical problem is not solved across the entire scope of the claim. Oxidized carbon black "A" differs from samples "B" to "E" in that it has a lower volatile content and a higher BET surface area. The claim, however, encompasses oxidized carbon blacks having a similar volatile content to sample "A" and an even higher BET surface area of up to 2 100 m**(2)/g. Such samples are closer to sample "A" than to samples "B" to "E". Considering that sample "A" does not solve the problem posed, it cannot be concluded that the problem would be solved by any such other samples encompassed by the scope of the claim."
• "In the light of the above, the objective technical problem is merely that of providing an alternative."
• The Board finds the modification to be obvious.
• Turning to the lower-ranking auxiliary request: "While the limitation does not provide an additional delimitation from D9, it does affect the question of whether the technical problem posed (see point 9.3) has been solved across the whole scope claimed.

  13.2 Oxidized carbon black "A" (BET surface area of 1 520 m**(2)/g, volatile content of 5.28%, Table 1 of the contested patent) is not included in the scope of the claim as its BET surface area is too high and its volatile content slightly too low. This example on its own thus does not call into question whether the problem is successfully solved. Moreover, the question of whether any technical effect may be achieved if the oxidized carbon black has an even higher BET surface area than sample "A" and a similar volatile content no longer arises since these samples are outside the scope of the claims."

• " For these reasons, and in the absence of any counter-evidence, the technical problem of obtaining improved dynamic charge acceptance and minimised water loss may be considered solved."

• The Board consides the technical facts and concludes that the claim is inventive.

EPO 

The link to the decision and an extract of it can be found after the jump.

https://www.epo.org/en/boards-of-appeal/decisions/t220355eu1

13. Inventive step

13.1 While the limitation does not provide an additional delimitation from D9, it does affect the question of whether the technical problem posed (see point 9.3) has been solved across the whole scope claimed.

13.2 Oxidized carbon black "A" (BET surface area of 1 520 m**(2)/g, volatile content of 5.28%, Table 1 of the contested patent) is not included in the scope of the claim as its BET surface area is too high and its volatile content slightly too low. This example on its own thus does not call into question whether the problem is successfully solved. Moreover, the question of whether any technical effect may be achieved if the oxidized carbon black has an even higher BET surface area than sample "A" and a similar volatile content no longer arises since these samples are outside the scope of the claims.

Example 6 illustrates the claimed invention. Example 6 relates to lead batteries in which the negative electrode paste contains, inter alia, PbO and the carbon black (sample "B" being according to the claimed invention). Oxidized carbon black "B" is derived from a carbon black having an OAN of 160 ml/100 g. There is no reason to expect that the processing would substantially affect the OAN, i.e. to such an extent that the OAN is then outside the broad range stipulated in the claim (from 35 to 500 ml/100 g). Moreover, this is confirmed by the additional data provided by the patent proprietor in the table on page 9 of the submission of 9 December 2022 (oxidized carbon black "B" has an OAN of 160 ml/100 g).

The experimental results provided in the patent in suit support that the technical problem - obtaining improved dynamic charge acceptance and minimised water loss (see point 9.3) - has been solved.

The examples as a whole show that this may be associated with the properties of the oxidized carbon black, i.e. that the oxidized carbon black according to the claim has beneficial properties for use in a lead-containing electrode composition (useful for a lead-acid cell where water loss is relevant). There is no evidence that this would be limited to a certain range of electrode compositions.

13.3 For these reasons, and in the absence of any counter-evidence, the technical problem of obtaining improved dynamic charge acceptance and minimised water loss may be considered solved.

13.4 Although D9 generally describes surface functionalisation (as indicated in point 9.8 above), there is no guidance to functionalise the surface such that one of properties (a)-(d) is fulfilled, in conjunction with a BET surface area within the claimed range. D9 also mentions a second carbon-based additive having a surface area of only 3 to 50 m**(2)/g, to which the teaching regarding surface functionalisation may likewise apply. Furthermore, D9 does not associate surface functionalisation with the intended effect of balancing dynamic charge acceptance and water loss.

The opponent, relying on analytical report D31, was of the view that the commercial material Raven 3500, mentioned along with various others in paragraph [0057] of D9, inherently exhibited properties (a)-(d). The patent proprietor contested this and argued that D31 was irrelevant and late-filed and should be disregarded.

Even if it were accepted - in the opponent's favour - that Raven 3500 has at least one of properties (a)-(d) as an inherent property, this cannot amount to a prompt to provide that property in high-BET-surface-area carbons in order to solve the technical problem posed, because neither these properties nor the technical problem are explicitly addressed.

The opponent did not identify any teaching in the prior art that would prompt the skilled person to provide one of properties (a)-(d) in order to solve the technical problem posed.

13.5 The commercial carbon black Raven 3500 does not constitute a more promising starting point within D9. As set out in relation to novelty, its BET surface area is below the claimed range. Irrespective of whether Raven 3500 exhibits one of properties (a)-(d) as an inherent property, none of them is specifically addressed in D9, as indicated. The general disclosure of D9 consequently provides no basis for extracting any such inherent property of an individual commercial carbon and generalising it, such as by combining it with a higher BET surface area.

13.6 The objection of lack of inventive step in view of D9 is therefore not convincing.