Patent ID: 10323118

Abstract:
A polyurethane foam based on MDI (diphenylmethane diisocyanate) and on a polyol with an ethylene oxide content of greater than 50%, is made by mixing, under pressure, to form a foaming liquid precursor of polyurethane foam: a first reactive liquid, referred to as liquid A, comprising (a) a urethane prepolymer based on a first portion of the MDI and on a first portion of said polyol, and (b) the second portion of the MDI in the free state, said prepolymer being dissolved in this second portion of MDI and a second reactive liquid, referred to as liquid B, comprising the second portion of said polyol and water as foaming agent. The amount of said polyol in the liquid B represents between 25% and 75% by weight of the total of said polyol; this method is advantageously used for casting a polyurethane foam into the cavity of a tire casing.