A Statistical Method For Synthesizing Pigment Dispersant And Its Application In Paper Coating Process

Coating pigment particles are prone to form aggregate because of their high surface force, posing extraordinary risk to the runnability of coating machine and coating paper quality; therefore, in effort to attain an objective of well-dispersed coating pigment slurry and superior runnability of coating machine, the best strategy is to make use of high-quality dispersant in pigment dispersing process.This paper applied statistical method to study the process for preparing water-soluble dispersant copolymers of maleric anhydride and acrylic acid, which had been formed by gradually and simultaneously adding monomers and initiator, to a reaction vessel initially containing water and activator at a temperature suitable for polymerization. The copolymers synthesized in this avenue had consistent compositions, low monomer residuals and excellent properties as pigment dispersant.The results of Blackett-Burman Screening Design show that ratio of monomer and polymeric temperature are important factors for the molecular weight of copolymer; while ratio of initiators, dosage of activator, ratio of monomers and maintaining time are significant factors for the monomer residuals.The results of General Full-Factor Design illustrate that the molecular weight of copolymer increased with the increase of ration of monomers or the decrease of polymeric temperature. The regression model for molecular weight, in which ratio of monomers, polymeric temperature and the interaction between them were chosen as factors, is: Mw= -18832 + 15756 (ratio of monomers) + 213 (polymeric temperature) -167 (ratio of monomers×?polymeric temperature)The most efficient dispersant -Super-JM dispersant, determined by the measure of being applied into the practice of clay dispersing is synthesized under the key conditions of ratio of monomers of 2:1 and polymeric temperature of 90 . Besides, through the comparison with the market dispersant used in Gold East Paper Co. Ltd, Super-JM dispersant is superior to the former in the field of achieving low viscosity of clay and GCC slurry, improving rheology behavior of coating and surface quality of coating paper.