自交联核壳丙烯酸乳液的构建及对水性油墨的影响

Construction of self-crosslinking core-shell acrylic emulsion and their effect on water-based ink

摘要:

以丙烯酸（AA）、丙烯酸丁酯（BA）、甲基丙烯酸甲酯（MMA）、丙烯酸羟丙酯（HPA）、甲基丙烯酸羟乙酯（HEMA）作为基础单体，乙二醇二甲基丙烯酸酯（EGDMA）、甲基丙烯酸缩水甘油酯（GMA）为交联单体，采用两步乳液聚合法制备了自交联核壳丙烯酸乳液，进一步将其作为水性油墨连接料制备水性油墨。通过交互正交试验考察核壳特性影响油墨耐水性和附着力的显著性因素，探究显著性因素确定最佳制备自交联核壳丙烯酸乳液的配方。利用TEM、FTIR、TG、DSC、吸水率、水接触角、万能材料试验机等表征和测试自交联核壳丙烯酸乳液及所制备胶膜的结构和性能，考察了壳层单体中GMA的质量分数对乳液粒径、稳定性和所制备油墨附着力、耐水性等的影响。结果表明，核层混合单体中与壳层混合单体中的AA质量比（核壳丙烯酸比）对油墨附着力影响显著，核层混合单体中与壳层混合单体中的MMA质量比（核壳软硬比）对油墨耐水性影响显著。自交联核壳丙烯酸乳液最佳配方为：核层混合单体与壳层混合单体的质量比（核壳质量比）2∶3、核壳软硬比3∶0.75、核壳丙烯酸比0.5∶2.5、内交联单体EGDMA用量0.75 g。当壳层单体中GMA的质量分数为1.5%时，自交联核壳丙烯酸乳液平均粒径为112.2 nm，PDI为0.108，最大热分解速率在409 ℃，核层与壳层的玻璃化转变温度（Tg）分别为28.5和51.7 ℃，乳液分散稳定性最佳，所制备胶膜吸水率为34.55%，所制备油墨附着力为99%，耐水性达50次。

Abstract:

Using acrylic acid (AA), butyl acrylate (BA), methyl methacrylate (MMA), hydroxypropyl acrylate (HPA), hydroxyethyl methacrylate (HEMA) as the base monomers, ethylene glycol dimethacrylate (EGDMA) and glycidyl methacrylate (GMA) as the cross-linking monomers, self-crosslinking core-shell acrylic emulsions were prepared by two-step emulsion polymerization, and it was further used as a water-based ink linker to prepare water-based ink. The significance factors of the core-shell properties affecting the water resistance and adhesion of the inks were investigated by interactive orthogonal tests, and the optimum formulation for preparing self-crosslinking core-shell acrylic emulsion was determined by exploring the significance factors. The structure and properties of the self-crosslinked core-shell acrylic emulsions and the prepared latex films were characterized and tested by using TEM, FTIR, TG, DSC, water absorption, water contact angle, and universal materials testing machine, etc. The effects of the mass fraction of GMA in the shell layer monomer on the emulsion particle size, stability, and the adhesion and water resistance of the prepared inks were investigated. The results show that the AA mass ratio (core-shell acrylic acid ratio) between the core-layer mixed monomer and the shell-layer mixed monomer has a significant effect on ink adhesion, and the MMA mass ratio (core-shell softness/hardness ratio) between the core-layer mixed monomer and the shell-layer mixed monomer has a significant effect on the water resistance of the ink. The optimal formulation of the self-crosslinking core-shell acrylic emulsion is as follows: the mass ratio of the core layer mixed monomer to the shell layer mixed monomer (core-to-shell mass ratio) 2:3, the core-to-shell softness ratio 3:0.75, the core-to-shell acrylic ratio 0.5:2.5, and the amount of internal crosslinking monomer EGDMA is 0.75 g. When the mass fraction of GMA in the shell layer monomer was 1.5%, the average particle size of the self-crosslinked core-shell acrylic emulsion was 112.2 nm, the PDI was 0.108, the maximum thermal decomposition rate was at 409 ℃, and the glass transition temperatures (Tg) of the core and shell layers were 28.5 and 51.7 ℃, respectively. The dispersion stability of the emulsion was optimal, and the water absorption rate of the prepared latex film was 34.55%, and the adhesion of the prepared ink was 99%, and the water resistance was 50 times.