铝型材用丙烯酸酯类阴极电泳涂料树脂的合成及应用

Synthesis and applications of acrylic resin of cathodic electrophoretic coating for aluminum product

采用自由基溶液聚合方法,合成了可用于阴极电泳涂料的阳离子型丙烯酸树脂。研究了树脂的水溶性、交联度、分子量及其分布、玻璃化温度等的影响因素。结果表明,当共聚单体N 羟甲基丙烯酰胺(NMA)和甲基丙烯酸羟乙酯(HEMA)的质量分数分别为6%和15%时,树脂的交联度较高;当共聚物中氨基单体的质量分数为12%～20%,羟基单体的质量分数为12%～15%时,控制中和度在75%～80%范围内,所得的树脂水溶性优良;以偶氮二异丁腈(AIBN)为主引发剂,以过氧化苯甲酸叔戊酯(TAPB)为辅助引发剂,控制聚合温度为85～95℃,单体滴加时间为3h,即可较好地调节树脂的相对分子量及其分布,且所得的树脂颜色较浅。对树脂在铝片上电泳涂装后之涂膜性能测试实验表明,当玻璃化温度在30～60℃时,所得树脂性能优良,其涂膜厚度为10～15μm,硬度达4～5H,耐冲击强度50kg/cm2,附着力为1级。

<Abstrcat> A kind of acrylic cationic resin applied to cathodic electrophoretic coating was synthesized with the method of free-radical solution polymerization. The influent factors on water solubility, molecular weight and its distribution, cross-linking degree and glass transition temperature of acrylic resin were studied. The results show that high cross-linking degree of resin can be gained as the mass fraction of comonomer N-hydroxymethyl acrylamide (NMA)and hydroxyethacrylate (HEMA)are 6% and 15% respectively. And the resin has excellent water solubility as the mass fractions of amino and hydroxyl-monomers are ranging from 12 % to 20% and from 12% to 15% respectively , and the controlled neutralization degree is in the range from 75% to 80%. A light-colored resin can be gained. With well-adjusted relative molecular weight and distribution when azobisisobutyronitrile(AIBN)is used as a major initiator and tert-amyl benzoate hydroperoxide (TAPB)as auxiliary initiator, and the polymerization temperature is controlled in the range from 85 ℃ to 95 ℃ and monomer feeding time for a duration of 3 hours. The performances of acrylic resin coating were determined after the aluminum product is electrophoretic-finished. The tests show that when the resin's glass transition temperature is in the range from 30 ℃ to 60 ℃, coating film has good performances with thickness of 10～15 μm, hardness of 4～5 H, impact resistance of 50 kg/cm^2, adhesion of 1 grade.