In one or more embodiments, the present invention provides a novel approach to the addition of plasticizers for softening TPUs, i.e., lowering the durometer and the melt viscosity. This approach involves incorporating bonded sulfonate groups with quaternary ammonium counterions into the TPU. In one or more embodiments of the present invention, the softening of TPU is achieved by incorporating an ionic diol, such as N,N-bis (2-hydoxyethyl)-2-aminoethane-sulfonic acid (BES), coupled with various bulky alkyl ammonium cations, during the chain extension step of the TPU synthesis. It is believed that that steric hindrance of the bulky quaternary ammonium groups weakens the dipole-dipole interactions of the sulfonate groups and/or lowers the crystallinity of the hard block, thereby creating additional free volume that softens the polymer and lowers the melt viscosity.
在一个或多个实施例中,本发明提供了一种添加
增塑剂以软化热塑性聚
氨酯的新方法,即降低硬度和熔体粘度。这种方法是在热塑性聚
氨酯中加入具有季
铵反离子的键合
磺酸盐基团。在本发明的一个或多个实施例中,热塑性聚
氨酯的软化是通过在热塑性聚
氨酯合成的链延伸步骤中加入离子二元醇,如 N,N-双(2-羟乙基)-2-
氨基
乙烷-
磺酸(
BES),再加上各种笨重的烷基
铵阳离子来实现的。据信,笨重的季
铵基团的立体阻碍作用会削弱
磺酸基团的偶极-偶极相互作用和/或降低硬块的结晶度,从而产生额外的自由体积,软化聚合物并降低熔体粘度。