Polyurethane, elastic polyurethane fiber and polyesterpolycarbonatediol used for the same
AssigneeKuraray Co., Ltd.
InventorsYukiatsu Komiya, Setuo Yamashita, Koji Hirai
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Abstract
The present invention is directed to an elastic polyurethane obtained by copolymerization of a polymer diol of a polyesterpolycarbonate diol utilizing a long-chain diol having methyl branches or a mixed diol of a polyester diol and a polycarbonate diol, with an organic diisocyanate and a chain extender. Elastic fibers obtained by spinning said polyurethane have low tensile stress at low tensile strain zone and high tensile stress at high tensile strain zone.
Claims13
A polyurethane obtained by copolymerizing a polymer diol, an organic diisocyanate and a chain extender, said polyurethane having an inherent viscosity of 0.2 to 1.6 dl/g and being derived from a polyesterpolycarbonate diol .alpha., a mixed polymer diol .delta. comprising a polyester diol .beta. and a polycarbonate diol .gamma. in a weight ratio between .beta. and .gamma., .beta./.gamma., of 10/90 to 80/20, or a mixture comprising the polyesterpolycarbonate diol .alpha. and the mixed polymer diol .delta.;
- where:
- .alpha. is a polyesterpolycarbonate diol comprising the following structural units (I), (II) and (III) with a molar ratio of (I)/(II) of 90/10 to 20/80 and having a number average molecular weight of 1,000 to 3,500 ##STR13## wherein R.sup.1 represents a divalent organic group, ##STR14## wherein m and n are each 0 or an integer of 1 to 8 and the sum of m and n is an integer of 4 to 8;
- .beta. is a polyester diol comprising repeating units represented by ##STR15## wherein R.sup.2 represents one member selected from divalent organic groups, at least 50 mol % of which is ##STR16## and q represents an integer of 4 to 10, satisfying the following conditions (s) and (t) ##EQU4## wherein "total number of carbon atoms" means the total number of carbon atoms contained in the polymer diol and excluding those contained in the ester bonds thereof, and having a number average molecular weight of 1,000 to 3,500;
- and
- .gamma. is a polycarbonate diol comprising repeating units selected from the group consisting of structural units (V)+(VI), structural units (V)+(VII), structural units (V)+(VI)+(VII), structural units (VI)+(VII), and structural units (VI), said repeating units being linked with each other via carbonate bond,
- --(CH.sub.2).sub.r -- (V)
- wherein r represents an integer of 6 to 10, ##STR17## the molar ratio of [(VI)+(VII)]/[(V)+(VI)+(VIII)] being 0.1 to 1.0, and that of [(V)+(VI)]/[(V)+(VI)+(VII)] being also 0.1 to 1.0,
- and having a number average molecular weight of 1,000 to 3,000.
Dependencies are inferred from the claim text.