| 摘要 |
PROBLEM TO BE SOLVED: To obtain a low-density urethane-modified polyisocyanurate foam having a low brittleness and an excellent adhesion to various facing materials by reacting a specific polyisocyanate component with a specific polyol component. SOLUTION: This foam is obtd. by reacting a polyisocyanate component with a polyol component. The polyisocyanate component contains at least two diisocyanate compds., 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and the concn. of the former compd. (x wt.%) and that of the latter compd. (y wt.%) satisfy the relations: 100>=(x+y)>=50 and x>=y. The polyol component comprises a polyol, water, and formic acid, the sun of the amts. of water and formic acid being 0.5-6wt.% of the polyol and the wt. ratio of water to formic acid being (1:5)-(5:1). |
