I. Findings of Fact
The Invention
The invention relates to a method for making a substantially solvent-free coating composition.
The coating composition comprises a polyisocyanate component which contains heteroallophanate
groups and an isocyanate-reactive component. (Appellants’ specification, p. 1, lines 7-10). An object
of the invention is the formation of blister-free coatings having good hardness. (Appellants’
specification, p. 2, lines 13-16).
Appellants’ method claims 10-16 and 18-19 and appellants’ product claims 17 and 20 are said
to form two separately patentable groups of claims for purposes of review. 37 CFR
§ 1.192(c)(7). (Brief, Paper No. 23, p. 3). Claims 10 and 17 are representative of appellants’ claims
on appeal and are reproduced below:
10. A method for making a blister-free coating comprising:
(1) applying a substantially solvent-free binder composition to a substrate, the
solvent-free binder composition comprising:
a) a polyisocyanate component containing heteroallophanate groups
and having aromatically-bound isocyanate groups,
i) an NCO content of 3 to 16% by weight based on
the weight of the polyisocyanate component,
ii) an average functionality of 1.8 to 4,
iii) an allophanate group content (calculated as
C HN O , MW: 101) of 5 to 35% by weight,
2 2 3
based on the weight of the polyisocyanate component,
wherein the allophanate groups are prepared from
urethane groups that are the reaction product of a
linear aliphatic diisocyanate having an isocyanate
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Last modified: November 3, 2007