Appeal No. 1999-1390
Application No. 08/655,783
details of this appealed subject matter are recited in
illustrative claim 1 reproduced below:
1. A process for the production of thermoplastic
polyurethane elastomer comprising
(a) introducing and homogeneously mixing (A),
(B) and optional (C) in a first static mixer at a
shear rate of 500 to 50,000 s-1 and at a temperature of
50 to 250ºC, to form a substantially unreacted mixture
wherein no more than 10 wt.% of said (A) has reacted
and
(b) reacting said substantially unreacted
mixture in a second static mixer operating at a shear
rate of 1 to 100 s-1 and a temperature of 50 to 250ºC,
to form a thermoplastic polyurethane elastomer, and
(c) continuously degassing and extruding said
thermoplastic polyurethane elastomer,
wherein (A) denotes one or more isocyanates, and where
(B) denotes a mixture of (B1) and (B2) where B1 is 0
to 85 equivalent-% (relative to the isocyanate groups
in (A)) of one or more compounds having an average of
1.8 to 3.0 Zerewitinoff active hydrogen atoms and a
number average molecular weight of 450 to 10000, and
where B2 is 15 to 100 equivalent-% (relative to the
isocyanate groups in (A)) of one or more chain
extenders having an average of 1.8 to 3.0 Zerewitinoff
active hydrogen atoms and a molecular weight of 62 to
400, and where (C) is an amount up to 20% (relative to
the weight of said thermoplastic polyurethane
elastomer) of auxiliary additives.
The examiner relies on the following prior art reference as
evidence of unpatentability:
Endmann et al. 2,823,762 Dec. 14, 1978
(Endmann)(published DE
patent application)
2
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