| 摘要 |
Compositions useful for curing polyurethane prepolymers, a process for their preparation and curable compositions prepared from them are described. To a dispersion of a complex of 3 moles of 4,4 min -methylenedianiline with 1 mole of a specified inorganic salt, preferably sodium chloride, in an inert liquid, which still contains some free methylenedianiline, there is added, with agitation, at least 0.5 equivalent of an organic isocyanate per equivalent of free methylenedianiline. Then, there is added, while continuing agitation, at least 0.5 weight % of lecithin. The resulting dispersion is a good curing agent for isocyanato-terminated polyurethane prepolymers. Compositions containing both the prepolymer and the curing agent of this invention have good shelf stability at room temperature and cure to polyurethane products having good physical properties and hydrolytic stability. |
