| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polyurethane resin solution favorably usable widely in various applications, which is transparent and high in viscosity stability, getting neither discolored nor thickened, and also causes no depolymerization thereof. SOLUTION: This method for producing a polyurethane resin solution comprises reaction in an organic solvent among (a) an organic diisocyanate, (b) a high-molecular diol 500-5,000 in number-average molecular weight, (c) a low-molecular diol <=300 in molecular weight and (d1) a monohydric alcohol <=200 in molecular weight, wherein the amount of the monohydric alcohol (d1) is 0.001-0.03 equivalent based on the total of the high-molecular diol (b) and the low-molecular diol (c), and a monohydric alcohol (d2) is added to the reaction system at a point when the free isocyanate group content per resin comes to 0.01-0.1 wt.%.
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