单体比例对苯丙乳液表面施胶剂性能的影响

Effect of Monomer Ratio on the Properties of Styrene-acrylic Emulsion Surface Sizing Agent

中文关键词:  单体比例  SAE表面施胶剂  玻璃化转变温度  Cobb值  纸张强度

Key Words:monomer ratio  SAE surface sizing agent  glass transition temperature  Cobb value  paper strength

中文摘要:

      以苯乙烯（St）为硬单体，丙烯酸丁酯（BA）为软单体，丙烯酸（AA，用量为单体总质量的5%）为功能性交联单体，合成了苯乙烯丙烯酸酯（SAE）聚合乳液，并将SAE聚合乳液与氧化淀粉复配（SAE聚合乳液的添加量为氧化淀粉绝干质量的5%）对纸张（牛皮箱纸板，定量130 g/m2）进行表面施胶。探讨了单体比例（m(St)∶m(BA)）对SAE聚合乳液玻璃化转变温度及稳定性的影响。结果表明，SAE聚合乳液的玻璃化转变温度随硬单体用量的增加呈线性上升，并且与采用L. Mandelkern方程计算的结果具有较好的一致性；SAE聚合物分子质量和乳液表观黏度随硬单体用量的增加均逐渐降低，乳液稳定性略有下降。与只用氧化淀粉施胶后的纸张相比，在相同涂布量下，经SAE表面施胶剂施胶后的纸张的Cobb值低，印刷表面强度和耐破度均有不同程度提高；当m(St)/m(BA)＝80∶20时，经SAE表面施胶剂施胶后纸张的Cobb值降低了51.8%，印刷表面强度和耐破度分别提高了58.0%和5.2%。

Abstract:

      With styrene (St) as hard monomer, butyl acrylate (BA) as soft monomer, and acrylic acid (AA) as functional monomer, a styrene acrylic ester (SAE) copolymer emulsion was synthetized, and this emulsion was used combined with the oxidized starch as paper surface sizing agent. The effects of the monomer ratio (the mass ratio) on the emulsion glass transition temperature (Tg) and stability were analyzed. The results showed that the Tg rose linearly with the amount of styrene increased, and this trend was in accordance with the result of L.Mandelkern equation. With the increase of styrene dosage, the molecular weight and viscosity declined gradually, emulsion stability decreased. The properties of sized paper with the emulsion, such as water resistance, surface strength and bursting strength, were affected by the styrene content. When styrene proportion was 80% of the total monomer, surface sized with the polymer combined with oxidized starch, Cobb value of the sized paper decreased by 51.8%, surface strength and bursting strength improved by 58.0% and 5.2% respectively, compared to sized by oxidized starch.