Process for preparing a polyurethane material

The method for preparing glass transition temperature of the 25℃ method of polyurethane material, wherein the method does not contain to a polyisocyanate and isocyanate reactive, regards to achieve, wherein less than 5 wt% (according to the weight of the isocyanate reactive composition is standard) in the water with the reaction, the reaction 80 to 140 of the isocyanate index, polyisocyanate is a) 80-100 by weight diphenylmethane diisocyanate, comprising at least 40 wt%, preferably at least 60 wt% and optimal preferred at least 85% wt% 4-4' - diphenyl methane diisocyanate and/or the diphenylmethane diisocyanateVariety, wherein the variety of 25℃ is liquid, and NCO value is at least 20 wt% (polyisocyanate a) and 20-0 wt% of one of polyisocyanate (polyisocyanate b), whichThe isocyanate reactive composition is a a) 80-100 by weight of the polyether polyol, wherein the average nominal method is 3-8, average equivalent of 200-2000, average molecular weight of 600-8000, ethylene oxide content is 50-100 wt%, preferably 75-100 by weight and content of hydroxyl (proportion of the total number of the compound is hydroxyl And a polyol), b) isocyanate reactive chain prolonging agent and/or crosslinking agent, wherein the amount of the rigid block ratio of 0.60 or above, preferably at least 0.65 and c not) wt% of except the one or more additional isocyanate reactive compound, the polyol a) and isocyanate reactive compound is) That of the polyol a) and compound (c) total amount of.