abstract |
Increased reactivity of isocyanate terminated polyether prepolymers with metal halide salt complexes of methylenedianiline is obtained when the polyether intermediates are modified to contain an effective amount of ethylene oxide. A desired intermediate is poly(oxypropylene) diol or triol which are modified to contain ethylene oxide units therein and subsequently reacted with a polyisocyanate such as MDI, that is 4,4′-diphenylmethane diisocyanate, or TDI, that is, toluene diisocyanate. A desired metal halide salt complex of methylenedianiline is the sodium chloride salt complex (MDA₃-NaCl), dispersed in dioctylphthalate (50/50 wt/wt). |