COMPOSITIONS OF POLYISOCIANATE AND PROCEDURE FOR THE PRODUCTION OF LOW DENSITY FOAMS WITH REMOVING SCALE IN AGING CONDITIONS IN A HUMID ATMOSPHERE FROM SUCH POLYISOCIANATE COMPOSITIONS.

摘要

A polyisocyanate composition having an NCO group content of more than 15% and comprising: (1) from 70 to 99% by weight, based on 100% by weight of (1) and (2), of a polymethylene-poly (phenylisocyanate) having an NCO group content of 30 to 33%, and a monomer content of 40 to 90% by weight, the monomer comprising less than 8% of 2, 2-diphenylmethanediisocyanate, 10 at 50% of 2, 4¿- diphenylmethanediisocyanate, and 50 to 90% of 4, 4¿- diphenylmethanediisocyanate, totaling the% by weight of the isomers 2, 2¿, 2, 4¿ and 4, 4¿ of diphenylmethanediisocyanate a 100% by weight of the monomer content; and (2) from 1 to 30% by weight, based on 100% by weight of (1) and (2), of a diphenylmethanediisocyanate prepolymer having an NCO group content of 2% to 20%, and comprising The reaction product of: (a) diphenylmethanediisocyanate comprising not more than 3% by weight of the 2, 2 ¿isomer, from 0.1 to 60% by weight of the 2, 4 ¿isomer and from 40 to 99.9% by weight of isomer 4, 4 ¿, totaling the% by weight of isomers 2, 2¿, 2, 4¿ and 4, 4¿ 100% by weight; and (b) a polyether polyol having a functionality of at least 2, a molecular weight of 500 to 10,000 and an OH number of 10 to 400, and being prepared by reacting a suitable initiator compound with ethylene oxide and propylene oxide in an OE weight ratio: OP from 50:50 to 90:10.