PURPOSE: To obtain a polyisocyanate mixture stable at room temp. over a long period of time and having film forming properties by reacting a specified polyisocyanate component and a hydroxycarboxylic acid component having a constant mol.wt.
CONSTITUTION: A polyisocyanate component (A) composed of diisocyanate with a mol.wt. of 168-1000 having a (cyclo)aliphatic bonded isocyanate group, a (cyclo)aliphatic bonded uretedione group and a hydroxycarboxylic acid component (B) composed of aliphatic hydroxycarboxylic acid having a mol.wt. of 76-200 are reacted with each other while an equivalent ratio of an isocyanate group and a hydroxyl group is held to (105:1)-(80:1), to obtain the objective mixture having average NCO functionality of 1.5-4.0 and containing 2-40 wt.% of the isocyanate group, 0.01-15 wt.% of the carboxyl group and 1-23 wt.% of the uretedione group.
HANSUUYOSEFU RAASU
BUERUNERU KUBITSUTSUA
