LOW TEMPERATURE DISSOCIATIVE BLOCKED ISOCYANATE AND COATING MATERIAL CONTAINING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a heat-hardenable type urethane sealing material without using a plasticizer or an organic solvent for coping with an environmental problem. SOLUTION: This heat-hardenable type urethane sealing material is composed of (A) blocked isocyanate, (B) an active hydrogen group-containing compound, (C) a dissociation catalyst and (D) a filler. In the sealing material, the blocked isocyanate is obtained by reacting (a) an aromatic diisocyanate with (b) a non- aromatic diisocyanate and (c) a polyol and a weight ratio of (a) to (b) is (a/b)=(30/70)-(70/30). The resultant prepolymer having isocyanate group terminals is mixed with (d) a blocking agent to obtain the objective sealing material.