丙烯酸树脂分散体对双组分水性聚氨酯性能的影响

Effect of acrylic dispersion on properties of two-component waterborne polyurethane

以过氧化二叔丁基为引发剂 ,丙二醇甲醚醋酸酯为溶剂 ,进行了丙烯酸酯溶液共聚合后 ,用水稀释得到丙烯酸树脂分散体。以丙烯酸树脂分散体与固化剂 (四甲基苯二甲基二异氰酸酯和三羟甲基丙烷的加成物 )组成水性双组分聚氨酯。系统研究了丙烯酸树脂分散体的玻璃化温度、分子量、羟基单体种类、羟值、酸值对涂膜性能的影响。研究表明 :增加丙烯酸树脂分散体的Tg、羟值和酸值 ,涂膜光泽、硬度、耐溶剂性等性能随之下降。表干时间则随分子量、羟值、酸值的增加而相应缩短。用丙烯酸羟乙酯代替甲基丙烯酸羟乙酯作羟基单体 ,涂膜表面无气泡、表干时间短、柔韧性好。

Acrylic dispersion was prepared by adding water into polyacrylic solution which was carried out in the present of propylene glycol monomethyl ether acetate using di-tert-butyl peroxide as initiator. Two-component waterborne polyurethane was made up of curing agent(the adduct of meta-tetramethylxylene diisocyanate and trimethylol propane) and acrylic dispersion. The effects of Tg, molecular weight, hydroxyl number, various hydroxyl monomers, acid number of acrylic dispersion on properties of films were studied systematically. The result showed that gloss, hardness and solvent resistance of films decreased with the increase of Tg, hydroxyl number and acid number, whereas the tack-free time was shorten with the increase of molecular weight,hydroxyl number and acid number. With 2-hydroxyethyl acrylate instead of 2-hydroxyethyl methacrylate, the films without blister had shorter tack-free time and better flexibility.