预聚体长期存放后NCO含量下降的原因及补救

The Remediation of Prepolymer with Depressed NCO Content and the Causation Discussion

对一批因超期存放而造成NCO质量分数下降的预聚体产品 ,采用了添加 2 ,4 TDI以及把待处理预聚体与新鲜同类预聚体相混合这两种补救措施 ,均取得了较好的结果。介绍了操作方法以及处理前后预聚体及其弹性体的性能。并探讨了聚氨酯预聚体在长期存放后性能指标产生下降的原因。

To make use of a supply of overdue urethane prepolymer product with reduced NCO content, two remedial measures were adopted, one was adding 2,4 toluene diisocyanate, the other was blending fresh prepolymer with higher NCO content. The good results were gained. The processes are recommended, and the properties of the prepolymers and their elastomers are introduced. The causation of the reducing of the NCO content in long term storage of the prepolymer is also discussed.