3 May 2021

T 1338/18 - The discovery of the magnitude of an effect

 Key points

  • This opposition case is about a second non-medical use. Claim 1 is directed to, in translation: " Use of expanded graphite [having certain features such as density and particle size] in order to confer, on the composition which it forms with a thermoplastic polymer, superior thermal conductivity properties, comparable electrical conductivity properties and an improved fluidity, with respect to those obtained with the use of carbon nanotubes".
  • Prior art document A11 describes adding the same expanded graphite to a thermoplastic polymer and also teaches that this results in good thermal and electric conductivity, and also loss of fluidity, but compared to the thermoplastic polymer alone. A11 does not include a comparison of these properties with a reference product comprising thermoplastic polymer and carbon nanotubes. 
  • Claim 1 at issue specifies " improved fluidity, with respect to those obtained with the use of carbon nanotubes", i.e. the product comprising the polymer and expanded graphite (instead of carbon nanotubes) has improved fluidity compared to carbon nanotubes. I understand that improved fluidity means higher fluidity. So claim 1 appears to specify that the expanded graphite causes a small decrease of fluidity, upon addition to the polymer than carbon nanotubes. 
  • The Board has to decide whether this is a valid use feature under G2/88.
  • The Board reviews G2/88 and T231/85 and T59/87 as being illustrative.
  • The Board notes that in the present case, the use feature does not specify a new use of the expanded graphite, as was not contested by the patentee, but only the improvement in certain effects.
  • The Board, in translation (r.3.4): “However, there is nothing in decisions G 2/88 and G 6/88 to indicate that the discovery of the magnitude of an effect occurring during the use of a prior art product, when such effect was already known to be exerted by the said product, justifies that this magnitude, even compared to that obtained with another product which was known to have the same effect, can in itself serve as a basis for a technical characteristic of a functional nature.”.

  • Please check the original French text of the decision carefully before citing this decision. The above summary is provisional. 




T 1338/18 - 

https://www.epo.org/law-practice/case-law-appeals/recent/t181338fu1.html


(decision text omitted)

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