| 摘要 |
1,210,737. Coatings. ALLIED CHEMICAL CORP. 22 Aug., 1968 [14 Nov., 1967], No. 40271/68. Heading B2E. [Also in Division C3] Elastomeric cellular polyurethane substrates may be coated with thermoplastic polyurethanes prepared from (1) an isocyanate terminated prepolymer obtained by reaching (A) a polyol which is a hydroxyl terminated polyester, polyether or polyether-polyester polyol of average M.W. of 350 to 5000 and which is substantially free from aromatic isocyanate residues, with (B) an excess of an aliphatic or cycloaliphatic diisocyanate and (2) at most so much of a diamine which is hydrazine or a non-aromatic primary diamine as is required to react with all the free isocyanate groups in the prepolymer. The diisocyanate and the diamine being so selected that reaction between them in boiling methylene chloride in 0.4 to 0.5 molar concentration causes a definite turbidity within 25 seconds. |
