Friday, 4 November 2011

T 2115/08 – White & Deadly

The opponent filed an appeal against the decision of the Opposition Division to maintain the patent in amended form.

Claim 1 as maintained by the OD read (the additions with respect to claim 1 as granted are underlined):
A white sealable, flame-retardant, biaxially oriented polyester film with at least one sealable outer layer A, one base layer B, and one other outer layer C, characterised in that the sealable outer layer A comprises from 40 to 95 mol% of ethylene terephthalate and from 60 to 5 mol% of ethylene isophthalate, has an average roughness Ra smaller than 30 nm and has a surface gas flow time of from 500 to 4000 s, the minimum sealing temperature being smaller than or equal to 110°C and its seal seam strength smaller than or equal to 1.3 N/15 mm, in that the non-sealable outer layer C has a coefficient of friction COF smaller than 0.5 and an average roughness of from 40 to 100 nm, in that the outer layer C and, where appropriate, the sealable outer layer A and/or the base layer B, comprise a flame retardant, and in that white pigments have been added to the base layer B.
The Board found this claim to lack clarity:

*** Translation of the German original ***

[2.1] Claim 1 of the main request differs from claim 1 as granted, inter alia, in that the polyester film was limited to a white polyester film. The feature of a “white polyester film” is not contained in any of the granted claims. Therefore, it has to be examined whether this feature complies with the requirement of clarity pursuant to A 84.

According to A 84, the claims have to be clear. As explained in decision T 560/09 [2], this requirements implies that the skilled person can without any doubt distinguish embodiments encompassed by the claim from embodiments that are not encompassed by it. Therefore, in the present case, it has to be examined whether the feature “white polyester film” is clear for the skilled person reading claim 1 and in particular whether it is possible without any doubt to distinguish white polyester films from polyester films that are not white.

[2.1.1] The only information provided in claim 1 with respect to the whiteness of the polyester film is that there have to be white pigments in the base layer of the polyester film. If the content of white pigments in a transparent polyester film is increased, then the film will lose its transparency and become more and more cloudy (“milky”) until finally a white film is obtained. However, the claim does not give any indication for the amount of white pigments. In particular, there are no indications which degree of cloudiness or which white pigment content allows to consider the polyester film to be a “white polyester film”.

[2.1.2] Moreover, polyester films and the pigments contained therein can comprise not only white parts but also parts of different colour, such as grey or yellow parts. From page 6, line 58 of the opposed patent (“Thus the film has a brilliant, white appearance without having a yellow tint.”) one may conclude, by inverse inference, that white polyester films may have a yellow tint. However, there are no indications until which content of yellow a polyester film is to be considered “white” within the meaning of the claim.

[2.1.3] Finally, contrary to the assertions of the [patent proprietor] the white polyester film of claim 1 is not defined by a degree of whiteness above 70. Rather this definition is contained only in claim 4, which depends on claim 1, which implies that this is only a preferred feature. Thus claim 1 also encompasses embodiments that do not have this feature, i.e. polyester films having a degree of whiteness smaller than 70. However, the claim does not provide any information until which degree of whiteness polyester films are still covered by the claim feature “white polyester film”.

The [patent proprietor] has argued in this context that the definition of the degree of whiteness in claim 1 followed from the description, and in particular from the degree of whiteness of greater than 70 indicated in Table 1 of the opposed patent.

Table 1 as published in the corresponding U.S. patent
(“Inventive range” should perhaps have been translated as “Range according to the invention”)

The Board agrees with the [patent proprietor] that Table 1 indicates that a degree of whiteness of greater than 70 is said to be the range according to the invention. However, this conflicts with the claims of the opposed patent from which it follows that claim 1 comprises films having a degree of whiteness smaller than 70 (see the first paragraph of [2.1.3]).

Moreover, the wording of A 84 makes clear that a claim as such has to be clear (see, for instance, T 1129/97 [2.1.2-3]). Therefore, an explanation of the term “white” in the description of the opposed patent cannot lead to the expression “white polyester film” in claim 1, which as such is unclear, being considered to be clear.

[2.2] Therefore, the skilled person working in the field of polyester films cannot assign an unambiguous meaning to the feature “white polyester film” in claim 1 of the main request. In particular, he cannot determine the limit with respect to the degree of cloudiness/portion of white pigment, portion of yellow and/or degree of whiteness until which a film complies with the feature “white polyester film”. Thus it is not possible to distinguish without doubt between polyester films according to the claim and polyester films that are not covered by the claim. Therefore, the limitation to white polyester films which the [patent proprietor] has introduced into the claim leads to claim 1 being unclear.

[2.3] In its response to the appeal dated July 20, 2009, the [patent proprietor] has argued that the term “white” was a merely qualitative property assignment which helped the skilled person to understand the invention. Therefore, this term did not call for any closer definition.

This understanding appears to imply that the requirement of clarity is less stringent for qualitative features. However, this is in conflict with A 84, which does not provide for any distinction between qualitative and quantitative features but requires that claims have to be clear. Therefore, this argument of the [patent proprietor] cannot succeed. […]

The patent […] is revoked.

Should you wish to download the whole decision (in German), just click here.

The file wrapper can be found here.