Aliphatic, sinterable, thermoplastic polyurethane molding compositions with improved blooming behavior
Light-stable, sinterable, thermoplastic polyurethanes with improved blooming behavior and good thermal stability as well as good technical processability are produced from an aliphatic diisocyanate using one or more chain extenders corresponding to a specified formula. These polyurethanes are particularly useful in the production of molded articles, particularly molded articles for automotive interiors.
1. A light-stable, sinterable, thermoplastic polyurethane comprising the reaction product of
a) an isocyanate component comprising:
a1) from 70 to 100 mol. % of 1,6-hexamethylene diisocyanate and
a2) from 0 to 30 mol. % of an aliphatic diisocyanate other than 1,6-hexamethylene diisocyanate or a mixture of aliphatic and/or cycloaliphate diisocyanates which does not include 1,6-hexamethylene diisocyanate,
b) a chain extender component comprising:
b1) from 40 to 100 mol. % of at least one chain extender with a number average molecular weight between 104 and 500 g/mol corresponds to formula (I) or formula (II)
in which
R 1 represents a branched or unbranched alkylene radical with from 1 to 12 C atoms or an alkarylene radical with from 6 to 24 C atoms,
R 2 , R 4 each represents a branched or unbranched alkylene radical with from 1 to 12 C atoms or an alkoxyalkylene radical with from 1 to 12 C atoms or an alkarylene radical with from 6 to 24 C atoms or an alkoxyarylene radical with from 6 to 24 C atoms,
R 3 represents a branched or unbranched alkylene radical with from 1 to 8 C atoms,
n, m each represent 0 to 10, where n+m≧1, and
p represents 1 to 10,
b2) from 0 to 60 mol. % of a chain extender or a mixture of chain extenders having a number average molecular weight of from 60 to 400 g/mol which is different from the chain extender b1), and
c) at least one polyol component with a number average molecular weight of 450 to 6000 g/mol,
in the presence of
d) optionally, one or more catalysts,
with the addition of
e) from 0.1 to 5 wt. %, based on weight of the thermoplastic polyurethane, of light stabilizers,
f) optionally, further additives and/or auxiliary substances and
g) optionally, one or more chain terminators,
in which the ratio of the isocyanate groups of a) to isocyanate-reactive groups of b), c) and g) is from 0.9:1 to 1.1:1.
2. A thermally stable, light-stable molded article produced from the thermoplastic polyurethane of claim 1 .
3. Automobile interior parts produced from the thermoplastic polyurethane of claim 1 .