T 2119/14 - Unusual parameter; burden of proof

Key point

• In this opposition appeal, the Board considers a claim for a coating composition to be insufficiently disclosed due to an unusual parameter. The Board discusses the issue in great detail. I highlight two aspects, namely the general remarks about "the technical contribution"  and about the burden of proof.
• "sufficiency of disclosure may however still be acknowledged if a skilled person [] is able without undue burden, i.e. with reasonable effort, to identify and prepare within the alternatives covered by the broad structural definition of claim 1 those coating compositions that possess the claimed parametric requirement []. This reflects the general legal principle whereby the protection sought must correspond to the technical contribution made by the disclosed invention to the state of the art, which excludes the patent monopoly from being extended to subject-matter which, after reading the patent specification, would still not be at the disposal of the skilled person." 
• " As to the [patentee's] argument that it was up to the opponents to show that the preparation of the coating compositions in accordance with claim 1 amounted to an undue burden for the skilled person, the Board observes that each of the parties to the proceedings carries the burden of proof for the facts it alleges []. Who bears the burden of proof may be determined by the legal cases which the respective parties are trying to make. [] In the context of the opposition ground of sufficiency of disclosure, the weight of the submissions required to rebut the legal presumption that the patent meets that requirement of the EPC depends on its strength []. A strong presumption requires more substantial submissions than a weak one. " 
• The above remark seems entirely correct to me. The Board then applies it to the case at hand: "In the present case the existence of an undue burden results from the almost infinite number of coating compositions that fall under the structural definition given in claim 1, and the above established absence of a teaching in the patent in suit as to how select in an appropriate and straightforward manner the components of the coating composition so as to meet the unusual parametric requirement of claim 1. As a consequence, the onus of proof to demonstrate that the preparation of the coating compositions over the whole scope for which protection is sought does not necessitate an undue amount of work for the skilled person rested on the patent proprietor [].
• As a comment on how the Board applies the general rule to the case at hand, I think that in the present case, the opponent had firstly shown that the presumption of sufficiency of disclosure is weak (due to " almost infinite number of coating compositions that fall under the structural definition"), furthermore had met its burden of proof to rebut the presumption (by establishing the absence of a teaching in the patent in suit as to how select in an appropriate and straightforward manner the components of the coating composition), and that it is hence up to the patentee to file counter-evidence (e.g. that the lacking information is common general knowledge). 

EPO  T 2119/14 - link

"1. Coating composition for the manufacture of a car wash-resistant coating comprising
at least one hydroxyl-functional binder selected from the group of hydroxyl-functional acrylic binders and hydroxyl-functional polyester binders and one or more cross-linkers reactive with the reactive groups of the binder,
wherein the binder and cross-linkers are selected such that, after curing to a coating, the coating has an initial gloss of at least 81 GU and a loss of gloss (LoG) of less than 0.18, the loss of gloss being determined by the formula (I)

LoG = A + B.E'.(X)**(-1).10**((C.DeltaTg))+ D.(E')**(-0,5) (I)

wherein A = 0.0132, B = 1.0197, C = 0.0113, and D = 0.0566,
E' reflects the tensile storage modulus at 40°C in GPa,
DeltaTg the width of the glass transition temperature in °C, and
X the cross-link density parameter in kPa/K, [...]
and wherein, in case the at least one hydroxyl-functional binder is an acrylic binder, the acrylic binder comprises (1) [...]."

Reasons for the Decision

Main request

1. The objection that the invention lacks sufficiency of disclosure is directed against claim 1 defining a composition for the manufacture of a coating, which composition is characterized in terms of both structural features setting out the constituents of said composition and parametric features defining the coating obtained after curing said composition.

2.2 The appellant [patentee]  argued that in line with paragraph [0011] of the specification, it is the inventors' accomplishment to identify those parameters, in particular the tensile storage modulus E' at 40°C, the width of the glass transition temperature DeltaTg, and the cross-link density X, that uniquely and precisely determine and define the loss of gloss in car washing conditions and their mutual relation as expressed in mathematical formula (I) defining the parameter LoG. According to paragraph [0011] the calculated LoG value accurately describes the observed loss of gloss as a result of a car wash treatment.

2.3 Whether the calculated LoG value as defined in claim 1 accurately describes the observed loss of gloss as a result of a car wash treatment is not relevant for assessing sufficiency of disclosure, as the observed loss of gloss is not a feature defining the subject-matter of claim 1. It is referred to decision G 1/03 of the Enlarged Board of Appeal (OJ 2004, 413) in which it was pointed out concerning non-working embodiments (point 2.5.2, third paragraph of the reasons), that if "there is lack of reproducibility of the claimed invention, this may become relevant under the requirements of inventive step or sufficiency of disclosure. If an effect is expressed in a claim, there is lack of sufficient disclosure. Otherwise, i.e. if the effect is not expressed in a claim but is part of the problem to be solved, there is a problem of inventive step (T 939/92, OJ EPO 1996, 309)". Accordingly, the observed loss of gloss as a result of a car wash treatment would be rather to be taken into account for assessing the presence of an inventive step, i.e. for determining the problem successfully solved over the closest prior art by the claimed coating compositions defined among others by the inequality LoG < 0,18.

2.4 It is undisputed that all coating compositions defined by the structural features of present claim 1 do not necessarily meet the additional parametric requirements defined in that claim. In accordance with the established jurisprudence of the Boards of Appeal of the EPO, sufficiency of disclosure may however still be acknowledged if a skilled person, on the basis of the information provided in the patent specification and, if necessary, using common general knowledge, is able without undue burden, i.e. with reasonable effort, to identify and prepare within the alternatives covered by the broad structural definition of claim 1 those coating compositions that possess the claimed parametric requirement (Case Law of the Boards of Appeal, 8**(th) Edition, 2016, II.C, introduction and II.C.4.4, in particular decision T 435/91, OJ EPO 1995, 188, Reasons 2.2.1).

This reflects the general legal principle whereby the protection sought must correspond to the technical contribution made by the disclosed invention to the state of the art, which excludes the patent monopoly from being extended to subject-matter which, after reading the patent specification, would still not be at the disposal of the skilled person.

2.5 Accordingly, the question to be answered in relation to sufficiency of disclosure is rather the ability for the skilled person to prepare the coating compositions which fulfil the structural requirements of claim 1 and exhibit a tensile storage modulus E' at 40°C, a width of the glass transition temperature DeltaTg, and a cross-link density X so that the relationship LoG < 0,18 defined in claim 1 is also met.

Assessment of sufficiency of disclosure

Information provided in the specification

3. The teaching provided by the patent specification in relation to the achievement of the parametric definition of claim 1 is as far as hydroxyl-functional polyester binders analysed in the following sections.

[...]

Undue burden

9. The appellant's argument that the skilled person would need only a few experiments to arrive at coating compositions meeting the requirement set out in claim 1 is in the absence of any substantiated facts and corroborating evidence showing that this would be generally the case over the whole scope intended a mere speculation which cannot convince the Board. It lacks credibility as the need for only a few experiments, for example as to transform occasional failure into success, requires the existence of a known methodology which would first guide the skilled person toward coating compositions meeting the parametric requirements of claim 1. This methodology, however, does not emerge from the patent in suit, as indicated above.

9.1 In the absence of indication of suitable common general knowledge which would allow the skilled person to fill the gap between the teaching of the patent and in suit and that which would be needed to prepare coating compositions over the whole scope for which protection is sought, the skilled person is left for a large part of those coating compositions at best to develop such missing methodology or to find out by trial and error which coating compositions from the innumerable compositions corresponding to the broad structural teaching of the patent in suit meet the parametric conditions set out in claim 1. This amount in both situations to an undue burden for the skilled person.

9.2 As to the appellant's argument that it was up to the opponents to show that the preparation of the coating compositions in accordance with claim 1 amounted to an undue burden for the skilled person, the Board observes that each of the parties to the proceedings carries the burden of proof for the facts it alleges (Case Law, supra, III.G.5.1 and III.G.5.2). Who bears the burden of proof may be determined by the legal cases which the respective parties are trying to make. Whether it is discharged or not is assessed by the board based on all the relevant evidence put before it, including the teaching or lack of teaching in the patent in suit in relation to the choice of suitable components and their relative proportions for preparing coating compositions meeting the parametric requirements of claim 1. In the context of the opposition ground of sufficiency of disclosure, the weight of the submissions required to rebut the legal presumption that the patent meets that requirement of the EPC depends on its strength (T 0063/06 of 24 June 2008, point 3.3.1 of the reasons). A strong presumption requires more substantial submissions than a weak one. In the present case the existence of an undue burden results from the almost infinite number of coating compositions that fall under the structural definition given in claim 1, and the above established absence of a teaching in the patent in suit as to how select in an appropriate and straightforward manner the components of the coating composition so as to meet the unusual parametric requirement of claim 1. As a consequence, the onus of proof to demonstrate that the preparation of the coating compositions over the whole scope for which protection is sought does not necessitate an undue amount of work for the skilled person rested on the patent proprietor (here appellant).

10. Accordingly, the subject-matter of claim 1 lacks sufficiency of disclosure and the ground of opposition under Article 100(b) EPC prejudices the maintenance of the patent as granted. Therefore, the Appellant's main request is to be refused.