影响水性聚氨酯/丙烯酸酯光固化速度的因素

Study on the curing rate of ultraviolet curable water-borne polyurethane-acrylate

用甲苯二异氰酸酯、聚己二酸新戊二醇酯、二羟甲基丙酸合成水性聚氨酯,用含双键的甲基丙烯酸羟乙酯封端,制得质量分数为34%的水性聚氨酯/丙烯酸酯水分散液,分别用三种光引发剂固化。结果表明,其中2 羟基 2 甲基 苯丙酮适用于常温固化;1 [4 (2 羟乙氧基 苯基)] 2羟基 2 甲基 丙酮适用于高温条件。当以1 [4 (2 羟乙氧基 苯基)] 2羟基 2 甲基 丙酮为光引发剂,控制光固化温度为80℃,表面光照强度70mW/cm2,引发剂质量分数为4%时,涂膜凝胶化时间为55s,凝胶化程度为83.4%。此时冲击强度大于50kg·cm,吸水率4.69%,附着力1级,耐溶剂性达300次。

Water-borne polyurethane was prepared by using tolylene diisocyanate, polydimethyltrimethylene glycol adipate and dimethylolpropionic acid, then reacted with 2-hydroxyethyl methacrylate to cap the terminal —NCO groups. The obtained prepolymer was mixed with trimethylolpropane triacrylate, then neutralized with triethylamine, and dispersed in water to obtain the aqueous dispersion with the solid content of 34%. The photoinitiator 2,2-dimethoxy-1,2- diphenylethan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2- hydroxy- 2-methyl-1-propane-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one were used for UV solidification of the polyurethane-acrylate. The results showed that 2-hydroxy-2- methyl-1-phenyl-propan-1-one was well suited for being used at room temperature, while 1-[4-(2-hydroxyethoxy)-phenyl]-2- hydroxy-2-methyl-1-propane-1-one was applicable at high temperature. By using 4% 1-[4-(2-Hydroxyethoxy)- phenyl]-2-hydroxy-2-methyl-1- propane-1-one, the gel content reached 83.4% and the gelation time was 55 seconds. The cured film exhibited good solvent resistance, its water absorption was 4.69% and the impact strength was greater than 50kg·cm.