EP 2 920 270 B1 relates to a process for tertiary mineral oil production, i.e. a form of fracking known as polymer flooding.
Brief outline of the case
The patent was revoked for lack of sufficiency.
The proprietor appealed.
The board set aside the OD’s decision of lack of sufficiency and remitted to the OD.
The opponents’ point of view on sufficiency
The opponents raised three objections of insufficiency of disclosure in respect of of claim 1 of the main request:
Measurement of the molecular weight
The water-soluble polyacrylamide-copolymer has a weight average molecular weight Mw of from 5,000,000 g/mole to 30,000,000 g/mole.
The opponents argued that it was known to the skilled person that there were many different methods for measuring the molecular weight of a polymer. All of these methods measured a different property and therefore led to a different result.
The patent did not indicate any method for measuring the molecular weight of the polyacrylamide copolymer required by claim 1 of the MR. The skilled person thus faced an undue burden.
Particle size
The particles of the water-soluble polyacrylamide-copolymer have an average particle size of 0.4 µm to 5 µm.
The opponents argued that the patent did not disclose how to measure the average particle size of the water soluble polyacrylamide-copolymer particles required in claim 1 of the MR. While the proprietor had indicated laser diffraction as a suitable measurement method, this was not the only possible method.
Even if it were accepted that the skilled person would have used laser diffraction, different results were obtained depending on the instrument used and the operating conditions, leading to different results depending e.g. on the instrument being used.
Definition of surfactant C
The liquid dispersion polymer (LDP) composition comprises 0.1 % to 10 w% of at least two surfactants (C), wherein the surfactants (C) comprise 0.05 to 5 w% of at least a first surfactant (C1) capable of stabilizing water-in-oil-emulsions, and 0.05 to 5 w% by weight of at least a second surfactant (C2) capable of stabilizing the dispersion.
Since the content of the specific surfactants C1 + C2 amounted to at most 10% of surfactants (C), at least 90% of the surfactants (C) was undefined.
The patent did not contain any teaching guiding the skilled person in the selection of other surfactants besides (C1) and (C2).
The board’s decision
Measuring the molecular weight
Even when accepting the argument that viscometry was the only reliable method in view of the molecular weight values required by claim 1 of the MR, this does not lead to any insufficiency of disclosure. In fact, variations in e.g. the viscosimeter and operating conditions used for measuring the intrinsic viscosity can certainly lead to deviations in the obtained results in terms of the calculated molecular weight.
However, in the absence of any proof to the contrary, these deviations do not prevent the skilled person from preparing or selecting a copolymer fulfilling the weight average molecular weight requirement defined in claim 1 of the MR so that the claimed process is carried out.
Measuring of particle size
The claimed range spans more than one order of magnitude. If the skilled person were in doubt as to which average is meant by claim 1 of the main request, paragraph [0032] of the patent discloses that “the d50 value of the particle size distribution (number average)” is meant.
The same passage of the patent further discloses that this average particle size “may be measured by the skilled artisan using known techniques for determining the particle size distribution.”
In the same way as the weight average molecular weight, the d50 value (number average) of a particle size distribution is not an obscure parameter, but a well-known value used to characterise a particle size distribution.
The fact that different results might be obtained depending on the selected method and operating conditions could indeed lead to ambiguity in terms of the precise delimitation of the ambit of claim 1
However, the board is of the view that this potential ambiguity concerns only the clarity of the claim under Art 84, but does not lead to any insufficiency of disclosure.
In the absence of any proof to the contrary, the potential uncertainty as regards the average particle size of the water-soluble polyacrylamide-copolymer particles would not have prevented the skilled person from conducting the process steps required by claim 1 of the MR. In other words, an undue burden would not be placed on the skilled person trying to carry out the claimed process as a whole.
Definition of surfactants
Even when accepting that the sum of (C1) + (C2) as defined in claim 1 of the MR amounts to a maximum of 10% of component (C), thus leaving 90% of component (C) unspecified, claim 1 still specifies this 90% as being surfactants. Surfactants are well known to the skilled person. Therefore, the skilled person is free to select any available surfactant to obtain the remaining 90% of component (C) of the LDP composition.
Comments
What was apparently fatal for the opponents is the absence of any proof to the contrary, that the invention sufficiently disclosed. This position of the bord is a priori correct, but is rather academic as the experiments represent an undue burden.
Whilst at a pinch the board’s position on the definition of surfactants can be followed, this is not the case with the board’s position on measurements.
The case law of the board’s is divergent
In the absence of a measurement method for a parameter, some boards consider that it is a mere problem of clarity which cannot be raised in opposition, other than under G 3/14.
Other boards consider that the absence of a measurement method for a parameter is a problem of lack of sufficiency.
Some examples for clarity
In examination
T 2700/17 (aggregate disintegration degree parameter “ADD”)
T 967/08 and T 1819/07 (average particle size)
In opposition
T 250/15 (measurement of the molecular mass.
T 1255/14 (measurement of particle size)
T 1260/16 (kinematic viscosity)
T 719/14 (foaming level greater than 40%)
T 2666/17 (surface tension)
Some examples for sufficiency
In T 1845/14, the board held, that the ambiguities in respect of parameters in the granted claim were not open to a clarity objection under Art 84 according to G3/14, but might result in a lack of sufficiency under Art 83. This was the case there.
T 1845/14 is also interesting in that the board disapproved decisions T 593/09, T 815/07, T 172/99 and T 608/07 and rejected the criterion of depriving the skilled person of the promise of the invention as not supported by decisions of the EBA.
Further decisions of this kind are
T 2161/17 (gas surface velocity)
T 1188/15 (thickness measurement)
T 626/14 (thickness of an absorbable article)
T 45/10 (average particle size not defined and no measurement method in the description)
T 2341/17 (lack of a definition of the parameter d90 and of a suitable method of the measurement of this essential parameter).
If the lack of information about a method of measurement of a parameter is such that there are different methods, giving different results, the fact that such a patent is maintained in an opposition is a premium for slap dash drafting and examination.
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