| 摘要 |
An isocyanate prepolymer is made by providing an isocyanate component. A phosphite that is free of active hydrogen groups is introduced into the isocyanate component. An isocyanate-reactive component and a stoichiometric excess of the isocyanate component are reacted in the presence of the phosphite to make the isocyanate prepolymer. A polyurethane foam is made by reacting the isocyanate prepolymer and a second isocyanate-reactive component in the presence of a blowing agent. A composite article is made by forming an elastomeric layer on the outer surface of the polyurethane foam core. Due to the presence of the phosphite during reaction of the isocyanate component and the isocyanate-reactive component to make the isocyanate prepolymer, more efficient use of the phosphite is made, and the full color-reducing effect of the phosphite on the polyurethane foam is realized.
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