两步法合成防水透湿型水性聚氨酯的研究

Preparation of Waterproof and Moisture Permeable Waterborne Polyurethane by Two Steps Processes

预聚体制备中采用异氰酸酯两步投料法(两步法),通过在分子链的软段中引入亲水性的聚乙二醇合成了防水透湿型阴离子水性聚氨酯(WPU)。研究了聚乙二醇的相对分子质量、第一阶段预聚合中nNCO/nOH比值、异氰酸酯的复配对WPU乳胶的粒径、胶膜的力学性能和涂层织物的防水透湿性的影响。结果表明,在总nNCO/nOH=1.3,第一阶段预聚合nNCO/nOH=1.1,聚己内酯二元醇/聚乙二醇(PEG)为70/30(其中PEG包括PEG1000和PEG2000,质量分数分别为24%和6%),DMPA质量分数为6%,异氰酸酯IPDI/MDI质量比为50/50时,合成出的WPU涂层织物在38℃时的透湿量超过4000g/(m2.d),且耐静水压力达到4.3 kPa,具有良好的防水透湿性。

A series of waterproof and moisture permeable anionic waterborne polyurethane were synthesized by the method of feeding isocyanate by two steps processes in prepolymerization, and using hydrophilic polyethlene glycol that was put into the molecular chain as a part of soft segment. The influence of molecular weight of polyethlene glycol, the value of nNCO/nOH in the first stage of prepolymerization and the compounds of isocyanate on particle size of waterborne polyurethane, mechanical property of the film, and waterproof and permeable of textile coatings were researched. The results show that the water vapor permeability of the waterborne polyurethane coating fabrics exceeded 4000 g/（ m^2 .d） at 38℃ and the resistance to static water pressure of the coating fabrics was 4. 3 kPa, with the condition of nNCO/nOH was 1. 3, nNCO/nOH in the first stage was 1.1, mPCL/mPEG was 70/30 （ PEG was the compounds of PEG1000 and PEG2000,the contents were 24% and 6% respectively） ,DMPA content was 6% and the isocganate was the compounds of IPDI and MDI, the value of mIPDI/mMDI was 50/50.