| abstract |
A polyurethane resin forming composition comprising a chief ingredient (A) containing an isocyanate component, and a curing agent (B) containing a polyol component, wherein an isocyanate group-terminated prepolymer obtained by reacting an isocyanate group-containing compound (a1) with a polyfunctional polyether polyol (b1) obtained by using, as an initiator, a compound having a functionality of at least 6 is contained as the constituent of the chief ingredient (A); and a castor oil-modified polyol (b2) obtained from castor oil and/or a castor oil fatty acid and a trimethylolalkane is contained as the constituent of the curing agent (B). This composition has such a long pot life as to be applicable to the production of large-sized hollow-fiber membrane modules and can form cured resins excellent in adhesiveness and heat resistance, low in the temperature dependence of hardness and, in particular, extremely little in the amount of matter dissolved out in water when immersed in the water. |