丙烯酸含量、乳化工艺参数对水性聚氨酯丙烯酸酯及其紫外光固化膜性能的影响

Effect of Acrylic Acid Content and Emulsification Parameters on Physical Properties of Waterborne Polyurethane Acrylate Coating Cured with Ultraviolet

聚氨酯丙烯酸酯(PUA)兼具聚氨酯(PU)树脂和聚丙烯酸酯(PA)柔韧性优良、耐磨性、耐冲击性和粘结性好等优点,以往将其用于水性涂料的研究不多。以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸羟乙酯(HEA)、丙烯酸(AA)为原料制备了侧链带有不同比例羧基和羟基的聚丙烯酸酯(PA),然后与聚氨酯(PU)中间体反应,在水中分散得到聚氨酯丙烯酸酯乳液(WPUA),并采用紫外光(UV)固化成膜。采用傅立叶转换红外光谱(FTIR)和核磁共振光谱(1HNMR)对产物结构进行了表征,考察了乳化工艺参数对乳液粒径的影响,研究了丙烯酸含量、固含量、温度对分散乳液性能的影响,确定了合适的乳化工艺,并对WPUA UV固化成膜后的物理性能进行了表征。结果表明:随着AA含量的增加,WPUA乳液黏度升高,粒径先变小后变大,漆膜亲水性增强,AA含量控制在10%～15%较宜;WPUA乳液适宜的乳化工艺为剪切速率200 r/min,时间20 min;经UV固化所得涂层的物理性能较优。

A series of polyacrylate(PA) with different proportions of carboxyl and hydroxyl side-chains were synthesized from methyl-methacrylate(MMA),butyl-acrylate(BA),hydroxyethyl-acrylate(HEA) and acrylic-acid(AA) as the starting materials.As-synthesized PA was then allowed to react with polyurethane(PU) intermediate and dispersed in water generating polyurethane acrylate emulsion(WPUA) which was cured under ultraviolet irradiation affording polyurethane acrylate(PUA) coating.The structure of the products was characterized by means of Fourier transform infrared spectrometry and nuclear magnetic resonance spectroscopy.The effect of emulsification parameters on the size of the emulsion was examined,and the effects of acrylic acid content,solid content,and temperature on the properties of the dispersed emulsion were investigated.Furthermore,the proper emulsification process was established,and the physical properties of PUA coating cured by ultraviolet irradiation were evaluated.Results show that the viscosity of WPUA emulsion rises with increasing content of AA,while the size of the emulsion initially declines and rises later therewith.The proper content of AA is suggested as 10%～15%.The proper emulsification parameters for WPUA emulsion are suggested as shearing rate of 200 r/min and time of 20 min.Moreover,PUA coating cured under ultraviolet irradiation possesses desired physical properties.