Appeal No. 96-0736
Application 07/984,596
This is an appeal from the final rejection of claims l-6, 8,
and 9, all the claims remaining in the present application.
Claim 1 is illustrative:
1. Polyisocyanates based on a polyhydroxyl polyether having
a molecular weight of from about 350 to about 500 and tolylene
diisocyanate containing ether and urethane groups having
a) an NCO content of from about 11.8 to about 14.4% by
weight,
b) an average NCO functionality of from about 3.1 to about
4.0 and
c) a free tolylene diisocyanate content of less than about
0.1% by weight.
The examiner relies upon the following reference as evidence
of obviousness:
Schnabel et al. 4,385,171 May 24, 1983
(Schnabel)
Appellants’ claimed invention is directed to
polyisocyanates, and a process for their preparation, wherein the
polyisocyanates have the recited NCO content and average NCO
functionality, as well as a free tolylene diisocyanate content of
less than about 0.1% by weight. Since vapors from free tolylene
diisocyanate are toxic to humans, it is desirable to limit the
2
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