Patent ID: 7056976

Claim:
A reaction system for the preparation of a fiber reinforced composite according to the pultrusion process comprising: (a) a reaction mixture comprising an isocyanate reactive composition, a polyisocyanate composition, and optionally one or more additives; and (b) a continuous fiber reinforcing material, wherein the reaction mixture initially contains both free isocyanate groups and flee alcoholic —OH groups, has a gel time greater than 768 seconds at 25° C., and a gel time less than 120 seconds at 175° C.; and wherein the polyisocyanate composition comprises one or more polyisocyanates of the MDI series, has a number averaged functionality of isocyanate groups in the range of from 2.3 to 2.9, and a free isocyanate group content in the range of from 10% by weight to 33.6% by weight.