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以混合二异氰酸酯[六亚甲基二异氰酸酯(HDI)/异佛尔酮二异氰酸酯(IPDI)]和聚己二酸丁二醇酯(PBA-2000)为基本原料、二羟甲基丁酸(DMBA)为亲水性单体[代替目前常用的二羟甲基丙酸(DMPA)]、三乙胺(TEA)为中和剂和乙二胺(EDA)为扩链剂,反应过程中不添加有机溶剂和催化剂,采用先乳化后扩链的预聚体分散法制备了固含量为50%左右的水性聚氨酯(WPU)。采用单因素试验法优选出制备WPU乳液的较佳工艺条件。结果表明:当R=n(-NCO)∶n(-OH)=1.88∶1、w(DMBA)=4.1%和n(EDA)∶n(-NCO)=0.37∶1时,WPU胶膜的强度(拉伸强度为23 MPa)和韧性(断裂伸长率为740%)俱佳。
Based on a mixture of diisocyanates (HDI / IPDI) and polybutylene adipate (PBA-2000) as basic raw materials, dimethylolbutyric acid DMBA) is a hydrophilic monomer [instead of the commonly used dimethylolpropionic acid (DMPA)], triethylamine (TEA) as a neutralizer and ethylenediamine (EDA) as a chain extender, Addition of organic solvent and catalyst, the water-based polyurethane (WPU) with the solid content of about 50% was prepared by the method of prepolymer dispersion after emulsification and chain extension. The optimum conditions for preparation of WPU emulsion were optimized by single factor test. The results show that when the ratio of n (-NCO): n (-OH) = 1.88:1, w (DMBA) = 4.1% and n (EDA) Strength (tensile strength of 23 MPa) and toughness (elongation at break of 740%) are superb.