Thermoplastic polyurethane foam material, sneaker midsole and preparation method of foam material

The invention provides a thermoplastic polyurethane foam material which comprises diphenylmethane diisocyanate, polytetramethylene ether glycol, 1, 4-butanediol, a nucleating agent and a viscosity reducer, the viscosity reducer has a structure as shown in a formula (I), and each symbol in the formula (I) is as defined in the specification. Therefore, by using the specific viscosity reducer, the solubility of the supercritical nitrogen in the thermoplastic polyurethane foam material can be increased, so that the appearance defects of a foamed product are reduced, the density is effectively reduced, and the requirement of light weight is met. 本发明提供一种热塑性聚氨酯发泡材料，其包含二苯基甲烷二异氰酸酯、聚四亚甲基醚二醇、1,4-丁二醇、一成核剂及一降黏剂，且降黏剂具有如式(I)所示的一结构，式(I)中各符号是如说明书中所定义者。藉此，通过使用特定的降黏剂，有助于增加超临界氮气在热塑性聚氨酯发泡材料中的溶解度，进而减少发泡产品的外观缺陷并有效降低密度，以达到轻量化的需求。