新型高电荷密度AKD乳液的制备技术及施胶机理的研究

There are a lot of problems in the conventional AKD emulsion such as the lagging phenomenon, large dosage of AKD emulsion and controversy of sizing mechanism. In order to improve the sizing efficiency, curing speed and stability of the AKD emulsion, the high charge density polymer was synthetized as the emulsifier. Hydrophily, lipophilicity and cationic degree were adjusted by molecular design.The influence of molecular structure of the emulsifier on the stability, sizing performance of AKD emulsion was revealed. In order to improve sizing efficiency, the balance point between hydrophily and lipophilicity must be found, at which the emulsifier comprised hydrophilic group as less as possible. The reaction and morphologic change of AKD in emulsion process, sizing process and drying process, etc were studied. The sizing mechanism of AKD was researched through interfacial chemistryand quantum chemistry. This study has a significant economic and social benefits, and provides theoretical support and guidance for the development of high charge density AKD emulsion.

针对传统的AKD乳液存在施胶滞后、用量大、施胶机理有争议等问题，本项目以提高AKD乳液的施胶效率、熟化速度和稳定性为目标，合成了高电荷密度聚合物作为AKD的乳化剂，通过分子设计调控乳化剂的亲水性、亲油性以及阳离子度性，揭示乳化剂分子结构对AKD乳液的稳定性、施胶性能的影响规律。寻找乳化剂的亲憎平衡点，使乳化剂含有适宜的亲水性基团，以便于提高施胶效率。研究AKD在乳化、施胶、干燥等各个阶段发生的反应以及形态的变化，通过界面化学、量子化学相结合的方式对AKD的施胶机理进行深入研究，明确AKD产生抗水性的机理。本项目具有显著的经济效益和社会效益，为高电荷密度AKD乳液的制备提供技术支持与理论指导。

本项目主要针对AKD乳液施胶存在施胶滞后以及假施胶等问题，提出了采用高电荷密度的聚合物作为AKD的乳化剂来解决这一问题。主要研究了合成具有高电荷密度的聚二烯丙基二甲基氯化铵作为AKD的乳化剂来制备立熟型AKD施胶乳液，经立熟型AKD乳液施胶的纸张，可以达到下机完成90%以上的施胶效果。高电荷密度的聚合物在实际生产过程中存在一些弊端，为了解决这一问题，我们又筛选了固体表面活性剂作为AKD表面施胶剂的乳化剂，解决了操作、运输等问题，使得AKD的施胶成本大大降低。本项目的研究取得了极大的成果，新型的AKD乳液相对于传统的淀粉乳化型AKD乳液，用量可以降低1/3。我们接着对AKD的施胶机理做了进一步的研究，主要研究AKD的水解条件，包括AKD的水解温度、碱、PCC、硫酸铝等对AKD水解性能的影响，得出AKD在此环境下的水解程度，以及水解程度对AKD乳液施胶效果的影响，为AKD的存贮及施胶作为指导依据。本项目的开展，不仅解决了困扰多年的AKD施胶滞后问题，还降低了AKD施胶的成本，发展了新的一步法施胶工艺，对AKD的施胶机理也做出了准确的验证，对造纸工业的发展提供了理论支持与技术指导。