PURPOSE: To obtain the titled resin solution excellent in weather resistance, yellowing resistance and solution stability, by chain-extending a prepolymer comprising a polymer diol, a monoalcohol and an alicyclic diisocyanate with a specified aliphatic diamine in a solvent.
CONSTITUTION: An isocyanate-terminated perepolymer with partially blocked terminals is obtained by reacting (A) a polymer diol with (B) 0.02W0.3 eq., per eq. of the diol, of a monoalcohol of MW 32W400 (e.g., methyl alcohol) and (C) an alicyclic diisocyanate (e.g., 4,4'-dicyclohexylmethane diisocyanate) in an NCO/OH ratio of 1.5/1W3/1. The titled solution is obtained by chain-extending the above prepolymer in a solvent (e.g., toluene) with isophoronediamine or both isophoronediamine and an alicyclic diamine of MW ≤300 in an amount substantially equivalent to the NCO groups in the prepolymer.
ANDOU TAKAO
YAMASHITA SHINJI
