Patent ID: 6617369
Filing Date: 2003-09-09
Classification: C08G,Y10S

Abstract:
A process for preparing a visco-elastic polyurethane foam at an NCO index of 70-120, which process may be a one-shot or prepolymer process, comprising reacting:a) a polyisocyanate composition; b1) a polyoxyethylene-polyoxypropylene polyol, having an average nominal hydroxy functionality of 2-6, where the EO is present as tipped EO and/or random EO, the total EO content being at least 50% by weight; b2) a polyoxyethylene-polyoxypropylene polyol, having an average nominal hydroxy functionality of 2-6, where the EO is present as tipped EO and/or random EO, the total EO content being between 20-50% by weight, having a primary hydroxy content of at least 50% calculated on the amount of primary and secondary hydroxyl groups; b3) a polyoxyethylene-polyoxypropylene polyol, having an average nominal hydroxyl functionality of 2-6, having a primary hydroxy content of at least 50% calculated on the amount of primary and secondary hydroxyl groups, and having an EO content of from 10 to 20% by weight; and optionally b4) a polyalkyleneglycol having an average molecular weight from 100 to 1200; these polyols b1, b2, b3 and b4 being reacted according to the following proportions, based on the combined weights of b1, b2, b3 and b4, b1: 30-85 wt %, b2: 5-65 wt %, b3: 5-40 wt %, b4: 0-50 wt %; c) water; and d) additives and auxiliaries known per se; and where the polyisocyanate prepolymer has an NCO value above 20% in case the prepolymer process is used.