PURPOSE: To provide a prepolymer excellent in reactivity and storage stability and used for polyurethane elastomers by reacting an organic polyisocyanate with a polyoxyalkylenepolyol specified in the contents of specific ion components.
CONSTITUTION: An organic polyisocyanate is reacted with a polyoxyalkylenepolyol containing potassium ions and sodium ions in amounts of≤0.1ppm, respectively, and phosphate ions in an amount of ≤0.1ppm and not containing bromine ions to provide the prepolymer. The crude polyoxyalkylenepolyol produced by polymerizing an alkylene oxide in the presence of an alkaline catalyst is preferably neutralized with water and phosphoric acid.When the water content of the neutralized solution is 0.1-10wt.%,0.05-5wt.% of magnesium silicate as an adsorbent is added to the neutralized polyoxyalkylenepolyol to adsorb and remove the ion components, thus providing thedesired polyoxyalkylenepolyol.
HARA YASUNOBU
IZUKAWA TSUKURU
ASAI SEIJI
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