DOC《分类号：》

表面施胶;

低分子表面活性剂;

松香甘油酯 ABSTRACT In this paper, the application and sizing efficiency of cationic rosin sizes were investigated. The influences of the dosages of surfactants including dodecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium bromide, sorbitan oleate and nonyl phenol ethoxylate on the character of weakly charged cationic acrylate copolymer emulsifier and consequently on the performance of dispersed rosin size emulsified by the acrylate copolymer emulsifier were investigated by means of orthogonal experiment. A weakly charged cationic acrylate copolymer emulsifier prepared by the optimized formula of surfactants shows good emulsifying and stabilizing effects on melted rosin materials. A weakly charged anionic dispersed rosin size prepared by the weakly charged cationic acrylate copolymer emulsifier displays a high sizing efficiency. Then the function of glycerin rosin ester in stabilization and sizing development of cationic rosin size were investigated by using conventional sizing measurement, ESEM and XPS.The results show that glycerin rosin ester can significantly reduce the surface carboxyl groups of cationic rosin size, which prevents the aggregation of rosin particles and improves the stability of cationic rosin size. The improvement of the stability of cationic rosin size may enhance its sizing efficiency. However, the reduction of carboxyl groups by glycerin rosin ester lowers the sizing performance of cationic rosin size. At the same time, the interaction of alum and cationic dispersed rosin size under various conditions and its effect on the rosin sizing development were investigated. The results show that the existence of alum significantly increases the softening and melting points of the cationic dispersed rosin size and improves its distribution while does not prevent the melting and spreading of rosin size on paper surface. Alum also improves the hydrophobicity of rosin size film and promotes the formation of well constructed rosin film during drying. It is the addition level (not the ratio between the alum and rosin size) that is more important to the sizing development of cationic dispersed rosin size. Keywords: cationic dispersed rosin size;

surface sizing;

low molecular surfactant;

glycerol rosin ester 第1章 绪论 纸张主要是由亲水性的纤维素纤维交织而成的网状物,经良好打浆处理的纤维表面含有大量的细纤维,使得纸张具有典型的 微观粗糙 表面,这无疑加剧了纸张的亲水性能.为了适应纸张的疏水性要求,常通过向纸料中加入施胶剂,即通过浆内施胶的方式提高纸张的表观疏水性能,使纸张获得一定的施胶度.纸张浆内施胶剂一般为含有较大疏水基团的两亲性物质,既能通过其亲水基以适当的方式固着和均匀分布于纤维上,又能利用其疏水基团为纸张提供足够的表观疏水性能.目前常用的浆内施胶剂主要包括松香、烷基烯酮二聚体(AKD)和烯基琥珀酸酐(ASA)三大类. AKD与ASA均为纤维素反应型施胶剂,在纸机干燥部与纤维反应,形成酯键,定位在纤维上,在纤维表面形成疏水层,从而产生施胶效果.AKD施胶具有用量少(0.1%~0.3%)、可在中碱性条件下使用、可用碳酸钙做填料、不易水解、便于运输和贮存等优点.施胶存在的主要问题是乳液在高剪切力作用下,易破乳并且施胶滞后,纸页打滑,施胶费用较高等[1]. 1.1 松香化学简介 松香是松树分泌的黏稠液体经蒸馏而得到的一种天然树脂,主要成分为树脂酸,分子式为C19H29COOH,软化点75℃,熔点95~135℃,在热水中部分被乳化,在汽油、煤油中的溶解性较差,易溶于甲醇、乙醇、氯仿等有机溶剂,可与碳酸钠、氢氧化钠等反应生成松香酸钠或松香酸钾.松香按来源可分为三种类型:即脂松香、木松香和浮油(妥尔油)松香[3,4].枞酸是松香树脂酸的典型代表,其分子结构如图1.1所示: 图1.1 枞酸型松香的分子结构 由图1.1可知,松香酸分子是一种两性分子,由一个极性羧基和一个三元环组成,具有两个化学反应中心――羧基与双键.其用于浆内施胶基本作用原理为:极性部分将松香颗粒固定在纤维上,非极性部分使纤维具有疏水性,从而使纸张产生抗水性. 制备松香时,由于水分、热异构化、未冷却前受振动、制备工艺条件等影响,松香会出现不同程度的结晶.树脂酸的化学组成决定了松香结晶趋势的大小和松香结晶的晶体成分;