POLYISOCYANATE FOR FLEXIBLE POLYURETHANE FOAM

摘要

PROBLEM TO BE SOLVED: To obtain a high-resiliency foam by reacting a component comprising a plurality of polyisocyanates with a component comprising a plurality of polyols to obtain a polyisocyanate containing a specified amount of isocyanate groups. SOLUTION: Diphenylmethane diisocyanate (A) having two benzene rings in the molecule, a polyphenylenepolymethylene polyisocyanate (B) having at least three benzene rings in the molecule and tolylene diisocyanate (C) are mixed with each other in such amounts that the A/B ratio is (50-85)/(50-15) by weight, and that the (A+B)/C ratio is 100/(5-25) to obtain a polyisocyanate component. A polyether polyol having a number-average molecular weight of 300-5,000/OH and an average functionality of 2-8 and a polyester polyol having a number-average molecular weight of 300-5,000 and an average functionality of 2-3 are mixed with each other in a ratio of (45-75)/(55-25) by weight to obtain a polyol component. The polyol component is reacted with the polyisocyanate component to obtain a polyisocyanate having an isocyanato content of 5-35wt.%.