PURPOSE: To provide a composition having remarkably improved thixotropy and capable of keeping the thixotropic nature even by the addition of various additives or by kneading, by compounding a liquid polyurethane prepolymer with colloidal silica and a siloxane compound containing polyoxyethylene chain.
CONSTITUTION: The objective composition is obtained by compounding (A) a liquid or solution polyurethane prepolymer with (B) colloidal silica and (C) a siloxane compound having polyoxyethylene chain. The component A is the one prepared by bonding a polyisocyanate with an active hydrogen compound at an equivalent ratio (NCO/active H) of 0.8/1.0W5.0/1. The component C is preferably the one having a molecular weight of 500W30,000 and containing 40W90wt% oxyethylene chain (the average polymerization degree of the oxyethylene chain is preferably 5W60). The amount of the component B is 0.5W50pts.wt., preferably 1.0W20pts.wt. per 100pts.wt. of the component A, and that of the component C is 0.1W50pts.wt., preferably 1W20pts.wt. per 100pts.wt. of the component B.
KOBAYASHI ATSUO
AZUMA YUKIO
YAMAMOTO SHINICHIROU
