Soft thermoplastic polyurethane elastomer and preparation method thereof

The invention discloses thermoplastic polyurethane substantially free of plasticizers and having a Shore A hardness of 60 or less, wherein the thermoplastic polyurethane is prepared by a one-step polymerization of the following components: i) a linear polyol, ii) an organic diisocyanate, and iii) a diol chain extender mainly comprising ethylene glycol and/or 1,3-propanediol; wherein the number average molecular weight of the linear polyol (i) is in the range of from 1.5*10 g/mol to 5.0*10 g/mol. The thermoplastic polyurethane can be easily prepared by conventional preparation methods, and the thermoplastic polyurethane prepared by the method can be molded into products in actual processing cycles. Further, the thermoplastic polyurethane product has low shrinkage, good low temperature properties and good mechanical properties, and is substantially not hardened at low temperatures. 本发明公开了一种基本上不包含增塑剂且具有60以下的肖式A硬度的热塑性聚氨酯，其通过一步聚合下列组分而制备：i)直链多元醇，ii)有机二异氰酸酯和iii)主要包含乙二醇和/或1,3-丙二醇的二元醇扩链剂；其中所述直链多元醇(i)的数均分子量在1.5×103g/mo