Polyurethane, elastic polyurethane fiber and polyesterpolycarbonatediol used for the same

摘要

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.