| 摘要 |
Heat stabilization of polyurethane elastomer catalyzed with organo-metallic catalyst is accomplished by adding a minor amount of elemental sulfur or sulfur-donor material to the liquid mixture of polyol and organic polyisocyanate at the time the catalyst is added. The sulfur remains inert during the polymerization reaction, and as long as the temperature of the cured elastomer does not exceed about 200 DEG F. When the temperature of the urethane exceeds 200 DEG F, the sulfur reacts with the catalyst to form a metallic sulfide, which results in the complete neutralization, or deactivation of the catalyst. Elimination of the organo-metallic catalyst prevents depolymerization of the urethane, and the urethane therefore remains solid at high temperatures for much longer periods of time than has heretofore been possible. The amount of sulfur required to deactivate will depend upon the metal content of the organo-metallic catalyst.
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