| abstract |
Polyfunctional isocyanate/polyol compsns. are trimerised using as trimerising catalyst and coreactants, 0.5-40 wt.% Mannich diols of formula where na, nb are independently 1-4; nc, nd are both 1; and R is N(Y)CH2KO where Y is 1-6C alkyl and K is 2-furan-4-ylmethyl. Also claimed are rigid polyurethane foams, density 1.5-5 lbs/cu.ft., comprising reaction prods. of (A) 100 pts.w (I) where, independently na, nb are 1-4 and nc, nd are 1-2. R is O; (OCH2K)ne O where K is as above and ne is 1-10; (K)nfO where nf is 1-10; N(L)M where L is low alkyl or M and M is CH2KO; amino(XNH)ngX(M)2 where X is (CH2)2-6 and ng is 1-3; or gp. II where Z is (CH2)2-4; (B) 100-120 mol.% reactive polyisocyanate; and (c) a fluorocarbon blowing agent. Trimers are fluorocarbon-compatible and resultant rigid foams have closed cell structure and reduced flame hazard potential. |