Method for producing millable polyurethanes and polyurethane elastomers
OwnerHitoshi Shirasakainventor
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Abstract
A method for producing millable polyurethanes by first producing a poly-.epsilon.-caprolactone based diol, the poly-.epsilon.-caprolactone based diol containing a controlled average number of caprolactone units and having a molecular weight distribution; and reacting the poly-.epsilon.-caprolactone based diol with a diisocyanate to produce a polyurethane with a restricted crystallizability having a rubber elasticity. The resulting millable polyurethanes exhibit excellent hydrolysis resistance, show no crystallization at low temperatures and have excellent mechanical properties.
Claims13
A method for producing a crosslinkable millable polyurethane rubber having substantially no hard segments and being millable on conventional rubber machinery comprising the steps of:
- producing a poly-.epsilon.-caprolactone based diol represented by formula (I) ##STR3## wherein ( ) is a caprolactone unit;
- m and n are numbers of caprolactone units;
- and R.sub.1 is a divalent group derived from a polymerization initiator of formula R.sub.1,(OH).sub.2, the poly-.epsilon.-caprolactone based diol containing a controlled average number of caprolactone units and having a molecular weight distribution Mw/Mn of 1.0 to 1.5;
- and
- reacting said poly-.epsilon.-caprolactone based diol with a diisocyanate to produce a polyurethane rubber having a restricted crystallizability.
Dependencies are inferred from the claim text.