Brief outline of the case
The patent relates to a polymerizable liquid composition and a process for the production of organic glass as well as the organic glass obtained from the polymerization of said compositions.
The proprietor appealed against the decision of OD of maintaining the patent according to AR1 filed during the OP before the OD.
The OD decided that the new MR filed in opposition was considered lacking N over D5=WO 2008/092597 (Not in ISR) but not over D1=US 4,101,529 (1st doc in ISR=X,Y).
The MR in appeal was the MR in opposition.
Contrary to the OD, the board held that the MR was not lacking N over D5 but over D1.
The board held that claim 1 of AR 1 was allowable and remitted to the OD for the adaptation of the description.
Interpretation of claim 1 of the main request
Claim 1 reads “Polymerizable liquid compositions of polyurethane type made up of two components (A) and (B), where component (A) contains at least …. in the presence of an acid phosphate ester catalyst, between ….; the second component (B) contains ……. in absence of polyalkoxylated tertiary diamines and metal organic catalysts, said components (A) and (B) being present in weight ratio varying between 1:1 and 2:1; said polymerizable liquid compositions further comprising an acid phosphate ester catalyst”.
In its decision the OD considered that N over D1 was given considering that the term “metal organic catalyst” was not well-defined in the art and that, in view of paragraphs 44 and 45 of the patent specification, the presence of tetrabutyl titanate was excluded from the polymerisable composition being claimed due to the requirement “in absence of (…) metal organic catalysts”.
According to the decision, the latter feature was to be interpreted in its broadest sense, which was done when the term “metal organic catalyst” was read as meaning “any compound having a metal atom bound to an organic group“.
The issue in dispute between the parties boils down to assessing whether or not the feature “in absence of (…) metal organic catalysts” mandatorily excludes the presence of “tetrabutyl titanate”.
It was however not in dispute between the parties and the board that the term “metal organic catalysts” in claim 1, has no accepted and unambiguous definition in the art.
The proprietor and the OD put forward that in view of the lack of an accepted definition for the term “metal organic catalysts”, the skilled person would turn to the description of the patent specification to interpret it. In doing so, the skilled person would understand that tetrabutyl titanate was excluded from the scope of the claims in view of paragraphs 45 to 47 of the patent in suit.
The board considered that the passages of the patent in suit relied upon by the proprietor neither provide a clear and unambiguous definition of the term “metal organic catalyst”, nor specify that tetrabutyl titanate is a “metal organic catalyst”.
The board reminded first that the normal rule of claim construction is that the terms used in a claim should be given their broadest technically sensible meaning in the context of the claim in which they appear.
This meant that, in the present case, the broadest meaning of the feature “in absence of (…) metal organic catalyst” had to be established.
On the one hand, the board agreed with the OD and the proprietor that the feature “in absence of (…) metal organic catalyst” may, in view of its literal wording, be read as excluding the presence of “any compound having a metal atom bound to an organic group”. Following that reading, the compositions according to claim 1 would not encompass tetrabutyl titanate.
On the other hand, the board was also of the opinion that, as put forward by the opponent, the term “metal organic catalyst” can not only be read as meaning “any compound having a metal atom bound to an organic group”, but that it can also be read as being only related to a more restricted group of components, namely organometallic compounds comprising a metal-carbon bond as indicated in a standard technical dictionary in the field of chemistry.
The board was satisfied that a possible reasonable meaning of the feature “in the absence of … metal organic catalysts” only excludes the presence of compounds comprising a metal-carbon bond from the compositions being defined in claim 1. According to that reading, tetrabutyl titanate can be present in the compositions being claimed.
The board concluded that the wording “in the absence of … metal organic catalysts” can be read in at least two possibly reasonable manners:
- the first one excludes tetrabutyl titanate from the compositions being claimed
- the second one does not
However, reading claim 1 in its broadest sense, the presence of tetrabutyl titanate in the composition of example 7 of D1 cannot be seen as a feature distinguishing the subject-matter of operative claim 1 from said composition.
In other words, the presence of tetrabutyl titanate in the compositions according to example 7 of D1 cannot confer N to the subject-matter of claim 1 over that composition.
The board’s conclusion
The normal rule of claim construction of reading a feature specified in a claim in its broadest technically meaningful sense corresponds to determining the broadest scope encompassed by the subject-matter being claimed according to a technically sensible reading.
In the case of a feature defined in a positive manner, which imposes the presence of a specific element, this is effectively achieved by giving to the element in question its broadest technically sensible meaning.
However, for a feature defined in a negative manner, which excludes the presence of a specific element, the broadest scope of the claim corresponds to the narrowest (i.e. most limited) technically sensible definition of the element to be excluded.
Positive definition of a feature in a claim
The decision makes clear that in case of a positive definition of a feature in a claim, such a feature should be given the broadest technically sensible meaning.
This is standard practice and can lead in case of an unclear feature to an absence of N or IS as an unclear term cannot help to differentiate the subject-matter of the claim from the prior art, e.g. T 571/05.
Negative definition of a feature in a claim
The decision makes clear that in case of a feature defined in a negative manner, which excludes the presence of a specific element, the broadest scope of the claim corresponds to the narrowest technically sensible definition of the element to be excluded, that is the most limited definition of a negative feature.
This seem quite logical, but it is good for a board to have clarified the situation.
The present decision applies to disclosed disclaimers.
It would be interesting to see what a board would say in the presence of undisclosed disclaimers.
An undisclosed disclaimer should only remove the strict minimum to
- restore novelty over a prior art under Art 54(3) or an accidental anticipation or
- disclaim subject-matter which, under Art 52 to 57, is excluded from patentability for non-technical reasons.
In first instance, I am inclined to think that T 1553/19 can apply as well to undisclosed disclaimers.
What do you think?