Isocyanate-terminated prepolymer, the method for preparing the same and the use thereof

An isocyanate-terminated prepolymer, wherein the isocyanate-terminated prepolymer comprises the reaction product of reaction components of a1, a2 and a3:

• a1) 52-54% by weight of diphenylmethane diisocyanate (MDI), based on 100% by weight of the isocyanate-terminated prepolymer, wherein the diphenylmethane diisocyanate (MDI) comprises 73-79% by weight of 4,4′-diphenylmethane diisocyanate, based on 100% by weight of the diphenylmethane diisocyanate (MDI),
• a2) 34-36% by weight of polymethylene polyphenyl polyisocyanate (PMDI), based on 100% by weight of the isocyanate-terminated prepolymer, wherein the polymethylene polyphenyl polyisocyanate (PMDI) has an average functionality of from 2.6 to 2.8, and
• a3) 10-13% by weight of polyoxyethylene-polyoxypropylene polyol, based on 100% by weight of the isocyanate-terminated prepolymer, wherein the average functionality of the polyoxyethylene-polyoxypropylene polyol is 2-6, the average molecular weight is 2000-10000, and the average ethylene oxide content of the polyoxyethylene-polyoxypropylene polyol is 24-40% by weight, based on 100% by weight of the polyoxyethylene-polyoxypropylene polyol,
• wherein, the NCO content of the isocyanate-terminated prepolymer is 27-30% by weight, based on 100% by weight of the isocyanate-terminated prepolymer.