热塑性聚氨酯弹性体熔融指数影响因素的探讨

Discussion on influencing factors of thermoplastic polyurethane elastomer melt index

研究了软段结构、硬段结构、合成工艺等因素对热塑性聚氨酯（TPU）弹性体熔融指数的影响。结果表明：随多元醇相对分子质量增大,熔融指数降低;相同硬度条件下,聚碳酸酯型TPU比聚己内酯型TPU熔融指数低,1,4–丁二醇扩链比对苯二酚二羟乙基醚（HQEE）扩链熔融指数低;随着异氰酸酯指数或硬段含量增加,TPU熔融指数逐渐降低;合成反应温度越高,熔融指数越低;两步法工艺比一步法工艺有更好的加工流动性。

The influence of the factors including soft segment structure, hard segment structure,synthetic process etc. on the melt index of thermoplastic polyurethane（TPU） elastomer was investigated.The results show that with increasing the relative molecular mass of the polyols, the melt index decreases.Under the condition of same hardness, the melt index of the polycarbonate type TPU is lower than that of polycaprolactone type TPU, the melt index of the TPU extending with 1,4-butanediol is lower than that of TPU extending with hydroquinone bis（2-hydroxyethyl） ether（HQEE）. With increasing the isocyanate index or hard segment content, the melt index of TPU gradually decreases. The higher the synthetic reaction temperature, the lower the melt index. The two-step process possesses better processing fluidity compared to the one-step process.