聚氨酯水乳液的制备、性能及应用

Preparation Properties and Application of Aqueous Pclyurethane Emulsions

本文从聚氨酯的结构出发主要讨论了聚氨酯水乳液的制备过程、乳液及膜性能、应用领域及一些改性方法．水性聚氨酯的制备大多采用内乳化剂，讨论了乳化剂的种类及其乳化机理．水性聚氨酯的制备工艺主要有丙酮法、预聚体混合法及熔融分散法．其中丙酮法比较成熟、易控制、产品性能较好，但在经济上不合算．其它两种方法可以节省溶剂，但产品性能，特别是膜性能较差．对水性聚氨酯改性以改善其不良的耐水及耐溶剂性，主要有接枝及嵌段共聚改性和外交联剂改性等方法．

From the structure of polyurethane,the preparation process,physical properties of aqueous polyurethane emulsions and the derived films,along with some technologies to improve its properties were reviewed. The aqueous polyurethane emulsions is prepared by internal elnulsifier. The kinds of emulsifier and the emulsification mechanism were discussed. The main methods contain acetone process,prepolymer mixing process and melt dispersion process. The advantages of acetone process included the easy control,high quality of end products. However,distillation of large amount of acetone makes tile process economically unfavorable. Other methods save acetone,but have a poor quality of end products. Methods to improve the properties of the products,such as grafting and block copolymerization and crosslinking have been discussed.