| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a novel polycarbonate diol for obtaining a polyurethane having a good color tone, a low solution viscosity, excellent flexibility and elastic recovery, and excellent flexibility and bendability at low temperatures, while maintaining heat resistance, weather resistance and water resistance which are properties of a polyurethane derived from the conventional polycarbonate diol. <P>SOLUTION: The novel polycarbonate diol has a number average molecular weight of 250-5,000 and is obtained by polycondensing a dihydroxy compound and a carbonic acid diester as starting monomers by a transesterification reaction in the presence of a transesterification catalyst. The polycarbonate diol contains at least one metal selected from lithium and group 2 metals in the long form of the periodic table in a total amount of 1-100 μmol per 1 mol of all dihydroxy compound units, and has a Hazen color number measured according to JIS-K0071-1 (1998) of ≤60. <P>COPYRIGHT: (C)2013,JPO&INPIT |
