EFFECT OF FUNCTIONAL MONOMERS ON THE PROPERTIES OF CATIONIC STYRENE ACRYLATE EMULSION AND ITS SURFACE SIZING BEHAVIOR

摘要

A series of core-shell type cationic soap-free latex were prepared in this study by using starch(CS-8), styrene(St), butyl acrylate(BA) and methyl acrylate (MA) as main materials and introducing functional monomers (cationic monomers and water resistant functional monomers), which were added in drops continuously. Further, the characteristics of styrene acrylate emulsion (SAE) and its surface sizing behavior were determined. Through orthogonal experiments, the optimum conditions for copolymer’s synthesis are as follows: the weight ratio of styrene (St) and butyl acrylate(BA) is 7:10, the starch amount is 9%(wt), the charge for the initiator is 0.5%(wt), the amount of functional monomer is about 2%(wt), the holding time is 2.75hrs, and the temperature is about 86 degrees centigrade. In this study, DM (dimethylaminoethyl methacrylate), DAC (acryloyloxyethyltrimethyl ammonium chloride) and DMC (methacryloyloxyethyltrimethyl ammonium chloride) were selected as cationic monomers. The effect of the type and dosage of cationic monomer on the properties of SAE emulsion and its surface sizing behavior were investigated. The results of the experiment show that when DM is used with the dosage of 2%, the characteristics of the emulsion are much better. The results of the paper sized with SAE show that the Cobb value decreases by 50% and the tensile /ring crush strength increases significantly, compared to that of unsized paper. When the amount of rosin is 2%(wt), emulsion with excellent performance are obtained by dissolving rosin into the mixed monomers and charging in drops continuously, and the water-resistant performance of paper is improved significantly.