Reactive systems for prodn. of modified thermoset - comprises stable mixts. of poly:isocyanate(s), epoxide(s), graft copolymer rubber modifier, special catalysts and opt. other additives

摘要

Reactive systems (I) consist of (a) a stable mixt. of (i) organic polyisocyanate(s) and (ii) epoxide(s), with wt. ratio (i):(ii) such that 100 g (a) contains 0.005-0.4 mol. epoxide gps., (b) graft copolymer rubber as modifier, (c) catalysts and opt. (d) other additives etc.; the mixt. is stabilised by heating (ii), opt. in the presence of at least part of component (i), or (ii) is reacted with (i) in the presence of a tert. amine catalyst to give a highly viscous or solid intermediate contg. oxazolidinone and isocyanurate gps., and the reaction is stopped at max. 65% conversion of NCO gps. by addn. of an equiv. amt. of alkyl sulphonate alkylating agent. - Pref. (i) is a liq. polyisocyanate (mixt.) of the MDI series or a liq. deriv. thereof; (b) is a graft copolymer of vinyl monomers on a particulate, at least partly crosslinked rubber polymer, contg. 30-80 wt. % rubber; (c) are tert,. amines, imidazoles and/or latent catalysts such as tert. or quat. ammonium salts of alkylating or acid esters of organic phosphonic acids or phosphoric acid and/or boron trihalide/tert. amine addn. complexes.