Abstract: A composition for fiber-reinforced polyurethane resin, which comprises a long-fiber mat and a polyurethane composition, said polyurethane composition comprising:(a) an organic polyisocyanate,(b) a polyether polyol having a molecular weight of from 300 to 700, and having three or more functional groups,(c) ethylene glycol and/or 1,3 butanediol,(d) an imidazole represented by the general formula (1), as a curing catalyst, ##STR1## where m is an integer of from 1 to 4, and n is an integer of from 1 to 4.

Abstract: A method for producing a polyurethane type composite obtained by injecting a formulated liquid comprises an organic polyisocyanate, a polyol and a curing catalyst into a mold in which a fibrous reinforcing material is previously set, followed by curing, by means of a reaction injection molding machine, characterized in that:(1) a polyol component having a hydroxyl value of 300 to 800 is used as the polyol, and(2) an organic acid salt of a tertiary amine is used as the curing catalyst.

Abstract: A method for preparing a polyisocyanurate composite obtained by injecting a formulated liquid comprises an organic polyisocyanate, a polyol and a trimerization catalyst into a mold in which a fibrous reinforcing material is previously set by use of a reaction injection molding machine, wherein:(1) a single or mixed polyether polyol having a hydroxyl value of 40 to 400 is used as the polyol; and(2) the formulation ratio of the organic polyisocyanate and the polyol in terms of the isocyanurated isocyanate concentration [NCO].sub.T defined by the following formula (1) is in the range of 3.0 to 5.5 mmol/g: ##EQU1## [NCO].sub.T : theoretical concentration of isocyanate group consumed in isocyanuration;[NCO].sub.O : isocyanate group concentration in organic polyisocyanate (mmol/g);OH-V: hydroxyl value of single or mixed polyol;W.sub.A : weight fraction of organic polyisocyanate.