含双键丙烯酸酯共聚物乳液的制备及聚氨酯-丙烯酸酯UV双固化体系的研究

以甲基丙烯酸甲酯、丙烯酸丁酯、甲基丙烯酸、甲基丙烯酸烯丙酯为单体,乙氧基化烷基醚硫酸铵(CO-436)和壬基酚聚氧乙烯醚(NP-40)为复合乳化剂,制备了含双键的丙烯酸酯共聚物乳液;以4,4′-二环己基甲烷二异氰酸酯、聚酯二元醇、二羟甲基丙酸、甲基丙烯酸羟乙酯为原料制备了双键封端的聚氨酯丙烯酸酯乳液。将两种乳液混合涂膜,经水分挥发干燥成膜后进一步进行紫外光固化。考察了甲基丙烯酸烯丙酯单体用量、引发剂用量、乳化剂配伍对丙烯酸酯乳液聚合的影响,以及光引发剂用量和两种乳液配比对固化膜凝胶含量、吸水率和涂层硬度、柔韧性、抗冲击强度的影响。结果表明:当甲基丙烯酸烯丙酯用量在3.0%~6.0%之间时,能制得表观稳定的丙烯酸酯共聚物乳液,并有50%左右的烯丙基双键参与了分子内的交联反应,同时残留50%左右的双键;共混乳液的固化膜凝胶含量达95%以上,铅笔硬度最大达到4H,柔韧性1mm,抗冲击强度达到45 cm。

Study of the synthesis of acrylic emulsions with reactive vinyl groups and a dual-curing polyurethane-acrylate system

A series of polyacrylic latex materials with reactive vinyl groups have been successfully synthesized by the emulsion polymerization of acrylic monomers (methyl methacrylate, butyl acrylate, methyl acrylate and allyl methacrylate) in the presence of ammonium nonylphenyl sulphate (CO-436) and polyoxyethylene nonyl phenol e-thers (NP-40) as composite emulsifiers. A waterborne polyurethane emulsion terminated with vinyl groups was pre-pared from dieyclohexylmethylmethane-4,4'-diisocyanate, polyester diol, dimethylol propionic acid and 2-hydroxy-ethyl methacrylate. A dried coating of a mixture of the acrylic latex and polyurethane dispersion was obtained by heating and UV-curing. The effects of varying the amount of allyl methacrylate, initiator and emulsifier during acry-late polymerization, and the weight ratios of polyacrylic latex to polyurethane dispersion and photoinitiator on the cross-linking degree, water absorption and physical and mechanical properties of the coating were studied. The re-sults showed that a stable polyacrylate emulsion with reactive vinyl groups could be obtained when the content of al-lyl methacrylate ranged from 3.0% to 6.0% and approximately 50% of the reactive vinyl groups of the allylic pre-cursor remained in the latex. The gel content of the UV-cured film reached 95%, and the pencil hardness was 4H, the flexibility was 1 mm and the impact strength was 45 cm.