| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject resin excellent in balance of its physical properties such as a mechanical strength, a heat resistance and a hydrolysis resistance by performing transesterification of a specific dimer diol with a specific carbonate compound under a specific condition. SOLUTION: This method for producing a polyurethane resin is to form a polyurethane from a composition consisting of a polycarbonate diol of formula III [(n) is 1-50] obtained by transesterifying a dimer diol of the formula: HO-R- OH R is a diol residue of formula I [R1 , R2 are each an alkyl and the total of each of the carbon numbers of R1 , R2 and (p), (q) is 30] or formula II [R3 , R4 are each an alkyl and the total of each of the carbon numbers of R3 , R4 , (r), (s) is 34] in (70:30)-(80: 20) molar ratio of (formula I/formula II)] with a carbonate compound in the presence of a catalyst, while distilling alcohol, etc., off at 110-280 deg.C under an atmospheric pressure and then under a reduced pressure, a chain extender and an organic diisocyanate, in order to obtain an objective resin having units of formula IV and V (R' is an alkyl) in a molar ratio of (1/10)<=(formula IV/formula V)<=10 at random. |
