保定市分散剂厂

Organic pigments have been widely applied in many industrial fields due to their complete chromatography, high coloring strength, bright color and simple application. They are indispensable coloring materials for producing color inkjet printing ink. How to use organic pigment as a colorant to prepare stable color ink-jet printing ink is a hot topic at present. The results show that the organic pigment coloring strength increases with the average particle size decreased with increasing particle size, specific surface area increased to reduce the amount of pigment, so that the reflectivity increases, light scattering increases, we can obtain an optimal size value (about 100nm), above or below this value will make the coloring drop. However, as organic pigments are usually in the form of condensate, aggregates and other forms, and the surface polarity is low, it is difficult to be wetted and dispersed in the water phase. Especially when the pigment is nanoscale, the specific surface area and surface energy of the pigment increase sharply, and the tendency of automatic agglomeration increases, which results in the difficulty of dispersing organic pigment into nanometer size particles in the aqueous phase. The effective dispersing of organic pigments needs surface modification, so as to change the polarity of pigments, improve the compatibility of pigments and solvents, expand their application range and enhance their application performance.

颜料分散技术及分散剂的作用

The dispersing technology of pigment and the effect of dispersant

迄今为止，提高颜料在水性体系中的分散及分散稳定性的方法有多种，如松香处理法、颜料衍生物法、有机胺类处理法、添加分散剂法、等离子体处理法、超微粒子吸附法、微胶囊法等。其中添加分散剂法是使用最为广泛且分散效果较好的一种方法。在颜料分散过程中加入分散剂是保持颜料分散稳定的最有效方法，有些分散剂还兼有润湿作用，称作润湿分散剂。颜料分散剂主要通过以下两种作用保持颜料分散体的稳定：

Up to now, there are many methods to improve the dispersing and dispersing stability of pigments in aqueous system, such as rosin treatment, pigment derivative method, organic amine treatment, adding dispersant, plasma treatment, ultrafine adsorption, microcapsule and so on. Adding dispersant is one of the most widely used and better dispersing methods. Dispersing agent is the most effective way to keep pigment stable and disperse in the process of pigment dispersing. Some dispersants also have wetting effect, which is called wetting dispersant. The pigment dispersant maintains the stability of the pigment dispersions mainly through the following two effects:

（1） 电荷保护作用（双电层作用）。使颜料表面具有相同电荷，当微粒相互接触时由于带有相同电荷而相互排斥，带电微粒在库仑排斥力作用下维持了体系的稳定，其作用机理如图1 所示。

(1) charge protection (double layer action). The same charge is formed on the surface of the pigment. When particles are in contact with each other, they repel each other due to the same charge. The charged particles maintain the stability of the system under the action of Coulomb repulsion. The mechanism is shown in Figure 1.

（2） 立体保护作用（空间位阻作用）。颜料微粒表面覆盖的聚合物对微粒起到机械隔离作用，使颗粒间的接触变为不可能。聚合物与水之间的强烈作用可以阻止颜料粒子过分接近，其作用机理见图2。

(2) the effect of stereoscopic protection (space hindrance). The polymer covered by the surface of the pigment particles plays a mechanical isolation to the particles, making the contact between the particles impossible. The strong action of the polymer and water prevents the pigment particles from being too close. The mechanism of action is shown in Figure 2.

用于水性体系颜料分散的分散剂可以分为3类：

The dispersants used in the dispersion of pigment in the water system can be divided into 3 categories:

第一类为无机分散剂，如聚磷酸酯、硅酸盐等；

The first category is inorganic dispersing agent, such as polyphosphate, silicate and so on.

第二类为有机小分子分散剂，如阴离子型表面活性剂（烷基聚醚或烷芳基的硫酸盐、磷酸盐）、阳离子型表面活性剂（烷基吡啶氯化物等）、非离子型表面活性剂（如：聚氧化乙烯烷基芳基醚）和两性表面活性剂；

The second class of small organic molecules such as dispersing agent, anionic surfactant (dodecyl sulfate, phosphate or alkyl aryl polyether) and cationic surfactant (alkyl pyridinium chloride) and nonionic surfactant (e.g. polyoxyethylene alkyl aryl ether) and amphoteric surfactant;

第三类为高分子分散剂，目前应用较多的如聚丙烯酸钠盐、苯乙烯- 马来酸半酯化物、苯乙烯-（甲基）丙烯酸（酯）共聚物、丙烯酸-（甲基）丙烯酸酯共聚物等。传统的表面活性剂已越来越多地被高分子类分散剂所取代。高分子分散剂也称为超分散剂。常用于水性体系颜料分散的两类超分散剂为聚电解质类超分散剂和非离子型超分散剂，它们的结构为无规共聚物、接枝聚合物和嵌段共聚物等，其中无规共聚物较多。水溶性超分散剂的亲油基团可由芳基、烷基、烷芳基、烃基等提供，亲水性基团可由羧基、磺酸基、羟基、氨基及长的聚醚链提供。疏水端单体多为不饱和烃类，如苯乙烯、乙烯、丁二烯、二异丁烯、甲基乙烯醚、（甲基）丙烯酸酯、醋酸乙烯酯、α- 甲基苯乙烯等，常用的亲水单体有（甲基）丙烯酸、马来酸及它们的衍生物，比如丙烯酸- 丙烯酸酯（丙烯酰胺）共聚物，苯乙烯- 丙烯酸（酯）类共聚物，马来酸（酯）- 丙烯酸（酯）（苯乙烯）共聚物等。

The third type is polymer dispersant, which is widely applied at present, such as polyacrylic acid sodium salt, styrene maleic acid half esterification, styrene (methyl) acrylic acid ester copolymer, acrylic acid (methyl) acrylate copolymer and so on. More and more traditional surfactants have been replaced by polymer dispersants. Polymer dispersants are also called hyper dispersants. The two kinds of hyper dispersing agents commonly used in aqueous system disperse are polyelectrolyte superdispersants and nonionic superdispersants. Their structures are random copolymers, graft polymers and block copolymers, among which random copolymers are more. The oil soluble groups of water-soluble hyper dispersants can be provided by aryl, alkyl, alkyl aryl and alkyl groups. The hydrophilic groups can be provided by carboxyl, sulfonic, hydroxyl, amino and long polyether chains. Hydrophobic end monomer for unsaturated hydrocarbons, such as ethylene, styrene, butadiene, two isobutylene, methyl vinyl ether, (methyl) acrylate, vinyl acetate, methyl styrene, hydrophilic monomer used a (meth) acrylic acid, maleic acid and their derivatives, such as acrylic acid (acrylate acrylamide) copolymer of styrene acrylic acid (ester) copolymer, maleic acid (ester) - acrylic acid (ester) (styrene) copolymer.