Brief outline of the case
The patent relates to recyclable thermoplastic insulation with improved breakdown strength.
Claim 1 relates to the processes for forming a polymeric composition.
Claim 4 relates to a process for producing a coated conductor.
Claim 16 relates to a coated conductor.
The opponent appealed the decision of the OD to maintain the patent according to a new MR and an adapted description.
Eventually the appeal was dismissed
Choice of the closest prior art
The case is interesting as often the discussion within the framework of the PSA is about the choice of the CPA for the subject-matter of claim 1 as maintained.
The documents at stake are D2 and D4.
D2 = Satkowski, Michael M. “The Crystallization And Morphology Of Polyethylene And Its Blends”, Doctoral Dissertation, University of Massachusetts Amherst (1990)
D4 = Lin, Y. et al. “Space charge distribution and crystalline structure in low density polyethylene (LDPE) blended with high density polyethylene (HDPE)”, Polym. Int., 54, p. 465-470 (2005)
The opponent’s position
The opponent held that D2 is the CPA for claim 1 of the main request because the only distinguishing feature is the step of quenching. Said step having no technical effect, the subject-matter of claim 1 is not inventive over D2.
For the opponent, a piece of prior art on the basis of which the claimed invention is considered non-obvious cannot be “closer” than a document on the basis of which the claimed invention appears obvious. Therefore D2 cannot be ruled out as closest prior art.
The opponent further argued that the process of claim 1 is not limited to a particular technical field. Therefore the technical field of the available documents is irrelevant for the selection of the closest prior art.
The opponent also pointed out that D2 is concerned with the question of recyclability which is a problem to be solved in the opposed patent.
The proprietors’ position
The proprietors were of the opinion that D4 is the CPA because, contrary to D2, it relates to insulating materials for cables and wires.
The board’s position
The board found that D2 was not a reasonable document to be taken as the CPA.
According to established case law, a central consideration in selecting the closest prior art is that it must be directed to the same purpose or effect as the invention. Furthermore, a document cannot qualify as the CPA for an invention merely because of similarity in terms of technical features; its suitability for the desired use of the invention also has to be described (see Case Law of the Boards of Appeal, 10th edition 2022, I.D.3.2).
In the present case, the opposed patent pertains to insulating layers in wires and cables. Specifically, as shown in the examples of the patent (see table 2), compositions derived for a process according to claim 1 have interesting insulating properties, such as an improved alternative current breakdown strength.
D2 is however silent about any application in the field of insulating materials for cables and wires. In fact, D2 is a purely academic study having no recognisable industrial application.
Contrary to D2, documents exist, such as D4, which relate to polymeric compositions for use as insulation material in electric power cables. Already for that reason, the Board considered that the skilled person wishing to provide an insulating material, would have no reason to start from D2 as the CPA, but would consider documents such as D4 which pertain to the use of interest.
The opponent selected D2 as the CPA essentially because it requires the minimum of structural modifications to arrive at the subject-matter of claim 1.
For the board, this approach would be allowable if D2 were a realistic starting point for a further development in the field of insulating materials. However, D2 has no connection whatsoever to the technological field of the opposed patent. Hence, D2 cannot be considered to be a reasonable starting point and the choice of D2 as CPA is an inadmissible ex post facto approach which draws on knowledge of the invention.
This decision reminds us that the CPA has to at least have some connection with the subject-matter of the claim at stake.
Just an example: a hair curler with its openings looks very much like a drainage tube with its openings. Nobody, and certainly not a person skilled in the art, would consider a drainage pipe as CPA when a hair-curler is at stake and vice versa.