1335958 Polyisocyanate polymers SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 30 Aug 1972 [1 Sept 1971] 40149/72 Heading C3R [Also in Division B5] Shaped articles are prepared by curing a mixture comprising aromatic and aliphatic polyisocyanates in a weight ratio range from 1 : 2 to 3À5 : 1, a basic initiator and a co-initiator which is an epoxide, pivalolactone or a carbamic ester, the final curing temperature being from 100‹ to 200‹ C. In Examples mixtures of diphenylmethane-4,4SP1/SP-diisocyanate and 2,2,4-trimethylhexane-1,5-diisocyanate are cured using dimethylethanolamine and benzyldimethylamine as initiators and phenylglycidyl ether as coinitiator, to obtain castings and a laminate from impregnated glass cloth, the curing being completed by heating.
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