POLYISOCYANATE COMPOSITIONS FOR THE PREPARATION OF FLEXIBLE POLYURETHANE FOAMS

摘要

The invention provides a liquid polyisocyanate prepolymer composition which is a result of combining about 50 to 90 percent by weight of an isocyanate blend (a.) having 55 to 75 weight percent 4,4'-MDI, 17 to 27 weight percent 2,4'-MDI, 1 to 10 weight percent 3-ring MDI oligomer, and 1 to 15 weight percent n-ring MDI oligomer (n greater than 3); about 5 to 30 weight percent of a polyhydroxy containing polyol (b.) having a molecular weight of from 700 to about 6,000, and about 5 to 15 weight percent of a toluene diisocyanate (c.). The resulting isocyanate prepolymer composition has a free NCO content of from about 20 to 40 weight percent and particularly desirable flow characteristics. The invention further provides a method of making an isocyanate prepolymer composition, a process of making a polyurethane foam utilizing the isocyanate prepolymer composition of the invention, and polyurethane foams produced by the disclosed process.