MDI型水性聚氨酯膏化和黏度影响因素

The creaming and viscosity influence factors of MDI-type waterborne polyurethane

采用四氢呋喃均聚醚(PTMEG-1800),2,2-羟甲基丙酸(DMPA)和二苯基甲烷二异氰酸酯(MDI-50)等为原料合成聚氨酯预聚体,加入乙二胺(EDA)等后扩链得到水性聚氨酯乳液(WPU)。WPU乳液黏度的影响因素主要有搅拌速率、-NCO/-OH的量比值(R值)、乳胶粒子粒径大小等,合理控制黏度可以避免乳液膏化现象。实验结果表明:乳化时剪切速率在1500 r/min以上时,物料被快速剪切乳化成0.2~100μm的颗粒,乳化效果最好;当-NCO/-OH的量比值(R值)为1.28时,水性聚氨酯乳化黏度低,固含量较最高。

For this article,a series of Polyurethane prepolymers were synthesized from Tetrahydrofuran homopolyether(PTMEG-1800),2,2-hydroxymethylpropionic acid(DMPA)and Methylenediphenyl Diisocyanate(MDI-50),and then the Waterborne polyurethane emulsion(WPU)were obtained by adding ethylenediamine(EDA)and so on.The main influencing factors of WPU emulsion viscosity include agitation rate,molar ratio of-NCO/-OH(R value),particle size of latex particles,etc,reasonable control of viscosity can avoid the creaming phenomenon of emulsion.The results showed that the best emulsification effect was obtained when the shear rate was above 1500r/min and the material was rapidly emulsified into particles of 0.2-100 m.When the molar ratio(R value)of-NCO/-OH is 1.28,the emulsion viscosity of waterborne polyurethane is low and the solid content is the highest.