Sizing behavior of cationic dispersed rosin-ester on cellulose fibers

Cationic dispersed rosin-ester size was prepared by emulsifying melted fortified rosin and rosin glycerin ester with cationic polystyrene-acrylamide emulsion containing polyaminoamide-epichlorohydrin. Sizing behavior of the resulting cationic dispersed rosin-ester on cellulose fibers was investigated. Size morphology and distribution on fiber surfaces was observed by scanning electron microscopy (SEM). The molecular orientation in drying process was characterized using X-ray diffraction. The results showed that the cationic dispersed rosin-ester size gave high sizing degrees under neutral conditions when used with sufficient alum. It developed sufficient sizing degree without melting and spreading on the fiber surface although curing might further increase the sizing degree. However, the sizing performance greatly depended on the added alum when the rosin-ester size did not melt and spread on the fiber surface. The role of alum in the sizing process was tso prevent the rosin-ester size from unfavorable molecular orientation.