新型丙烯酸酯杂合乳液的合成与水性双组分聚氨酯涂料性能

以甲基丙烯酸-β-羟乙酯(HEMA)为羟基单体,采用种子乳液聚合工艺,结合即时中和与极性单体分段滴加等手段合成了羟值为98.8 mg(KOH)/g、固含量为45.0%的新型聚丙烯酸酯杂合乳液(PAH).TEM观察发现:队H由表层为羧酸盐覆盖的乳胶粒P1和富含-OH的乳胶粒P2组成.纳米粒度分析表明:相对于常规羟基聚丙烯酸乳液(HPAE),PAH的粒径分布更宽,平均粒径更小.针对PAH配制的水性双组分聚氨酯涂料(2K-WPU)的综合性能测试说明:当-COOH和-OH在P1和P2中的质量比分别为1∶0和1∶3时,涂膜性能最佳.傅里叶红外光谱(FT-IR)分析发现:涂膜固化过程中-NCO与-OH完全反应仅需3 d.原子力显微镜(AFM)分析显示:2K-WPU涂层结构致密且平整.

Synthesis of Novel Acrylic Hybrid Emulsions for Two-component Waterborne Polyurethane Coatings

A novel acrylic hybrid(PAH) emulsions with 98.8 mg(KOH)/g hydroxyl and 45.0%(wt)solid contents was synthesized by semi-batch seeded emulsion polymerization with β-hydroxyethyl methacrylate(HEMA) as a hydroxyl monomer.The polar monomers were multi-stages added and carboxyl groups were neutralized during the polymerization process.TEM photos exhibited that PAHs were composed of two kinds of emulsion particles including one covered with carboxy groups(P1) and the other carrying hydroxy groups(P2).Nano-granularity analysis indicated that average diameters of the PAHs were smaller and its particle distributions were much broader than those of the common hydroxyl polyacrylate emulsions(HPAE).Two component waterborne polyurethane coatings(2K-WPU) were prepared with PAH,and the properties of 2K-WPU films showed that the optimal mass ratio of carboxy / hydroxy groups in P1 and P2 were 1∶0 and 1∶3,respectively.The FT-IR spectra demonstrated that the reactions of —NCO and —OH in 2K-WPU films were completely finished in 3 days.AFM pictures indicated that the surface of 2K-WPU cured films were compact and flat.