T 1518/17 - The role of the CPA

Key points

• In this opposition appeal, the question was whether the problem-solution approach was to be applied from one closest prior art document, or two times from the two proposed starting point documents.
• The Board: “Two documents have been proposed as closest prior art, namely D2 and D5. [...] According to the problem-solution approach the first step is to identify the closest prior art, i.e. a document disclosing subject-matter conceived for the same purpose or aiming at the same objective as the claimed invention and having the most relevant technical features in common [...]. 
  Both D2 and D5 as well as the patent in suit relate to propylene based compositions for injection moulding to prepare articles for similar end uses, even if the precise property profile required differs. Nevertheless both documents in principle qualify as a suitable starting point for consideration of inventive step.”
• “A further criterion is that the closest prior art should have most features in common, i.e. require the minimum of modification. [In the present case] neither document can be considered as having more features in common or being a more promising starting point”
• “It is correct, as argued by the [patentee], that D2 does not present any consideration of elongation at break, whereas the patent in suit and D5 do consider this property.”
   
• The Board: “In this context, it is recalled that even if prior art for the same purpose is available it is not excluded that a document relating to a similar purpose might be considered to be either a better or at least an equally plausible choice as closest prior art if it were apparent that the subject-matter thereof could be adapted to the purpose of the claimed invention []. In the present situation this is clearly the case since, as noted above, both the patent in suit and D2 are directed to the provision of injection moulded articles with good impact properties, also at low temperature.” (emphasis added, note that the 'were apparent' phrase appears to look forward to the outcome of the test).
• “Accordingly either of D2 or D5 can be qualified as the closest prior art and it is necessary to consider inventive step based on each of these documents. In such circumstances where two documents are both suitable to serve as the closest prior art it is necessary that an inventive step be demonstrated with respect to each. A finding of obviousness in respect of one document will necessarily lead to the conclusion that the requirements of Article 56 EPC are not met even if carrying out the same exercise on the basis of the other document would lead to a different conclusion.”
• “On that basis the composition of claim 1 does not involve an inventive step starting from D2 as the closest prior art. In view of the conclusion reached, there is no need to perform the analysis starting from D5 as the closest prior art ”

EPO T 1518/17 -  link



2. Main request - inventive step

2.1 Closest prior art

The patent in suit relates to polypropylene compositions having an optimum balance of properties in particular improved elongation at break and impact strength at room and low temperatures (paragraphs [0001], [0006], [0012]). The compositions are intended for the production of moulded, in particular injection moulded, articles (paragraph [0029]).

Two documents have been proposed as closest prior art, namely D2 and D5.

D2 relates to polypropylene resin compositions with low shrinkage, excellent impact strength, high stiffness and scratch resistance (title, paragraph [0001]). In particular the document addresses the problem of avoiding shrinkage upon moulding (paragraph [0006]). Among the possible fields of use of the compositions is in body parts such as bumpers or trim and other interior components for automobiles (paragraph [0007]).

As observed by the appellant, elongation at break is not discussed in the document.

D5 is directed to elastomeric polyolefin compositions which are required to exhibit good elongation and impact strength at low temperatures without loss of rigidity (page 1, in particular final three paragraphs). Similar fields of use as in D2 are envisaged, as is injection moulding to form the articles (page 2, third paragraph).

According to the problem-solution approach the first step is to identify the closest prior art, i.e. a document disclosing subject-matter conceived for the same purpose or aiming at the same objective as the claimed invention and having the most relevant technical features in common (see "Case Law of the Boards of Appeal of the European Patent Office", Ninth Edition, 2019, section I.D.3.1).

Both D2 and D5 as well as the patent in suit relate to propylene based compositions for injection moulding to prepare articles for similar end uses, even if the precise property profile required differs. Nevertheless both documents in principle qualify as a suitable starting point for consideration of inventive step.

A further criterion is that the closest prior art should have most features in common, i.e. require the minimum of modification.
Both D2 and D5 relate to compositions of homopolypropylene and an ethylene/propylene copolymer (see the respective claim 1 of each document). Accordingly neither document can be considered as having more features in common or being a more promising starting point (ibid).

It is correct, as argued by the appellant, that D2 does not present any consideration of elongation at break, whereas the patent in suit and D5 do consider this property.
In this context it is recalled that even if prior art for the same purpose is available it is not excluded that a document relating to a similar purpose might be considered to be either a better or at least an equally plausible choice as closest prior art if it were apparent that the subject-matter thereof could be adapted to the purpose of the claimed invention (ibid, 3.4.1). In the present situation this is clearly the case since, as noted above, both the patent in suit and D2 are directed to the provision of injection moulded articles with good impact properties, also at low temperature.

Accordingly either of D2 or D5 can be qualified as the closest prior art and it is necessary to consider inventive step based on each of these documents.

In such circumstances where two documents are both suitable to serve as the closest prior art it is necessary that an inventive step be demonstrated with respect to each. A finding of obviousness in respect of one document will necessarily lead to the conclusion that the requirements of Article 56 EPC are not met even if carrying out the same exercise on the basis of the other document would lead to a different conclusion.