Patent ID: 6022444
Filing Date: 2000-02-08
Classification: C08G,C08L,Y10S

Abstract:
A polyisocyanate prepolymer binder for lignocellulose-containing raw materials having a viscosity of less than 1500 cps at 25.degree. C. and an NCO content of from about 25 to about 32% which requires a shorter processing time and emits less isocyanate during processing that is prepared by reactinga) a polyisocyanate mixture made up of1) from 50 to 60% by weight, based on total weight of a), of polyphenyl polymethylene polyisocyanate,2) from 40 to 50% by weight, based on total weight of a), of an isomer mixture of diphenylmethane diisocyanate which includes(i) from about 4 to about 30% by weight, based on a)2), of 2,4'-diphenylmethane diisocyanate and(ii) from about 70 to about 96% by weight, based on a)2), of 4,4'-diphenlymethane diisocyanate andb) at least one amine-initiated polyol having from 2 to 4 hydroxyl groups and a molecular weight of from about 3500 to about 4000in amounts such that the ratio of equivalents of hydroxyl groups to equivalents of isocyanate groups is from about 0.001:1.0 to about 0.20:1.0.