Cationic modification of AKD and its application as a neutral sizing agent

A large molecular sizing agent modified AKD was prepared through the reaction between alkyl ketene dimmer (AKD) and polyamide then cationization by epichlorohydrin. The large molecular sizing agent has high positive charge and emulsifiability. The sizing experiments results of bleached kraft hardwood pulp indicated that a sizing degree of 52 s is achieved when the dosages of 0.2% sizing agent, 1% cationic starch and 0.02% cationic polyacrylamide are used, the sizing degree is 35 s when the dosage of sizing agent is the same but other retention aids are not used, which shows the sizing agent has higher self-retention ability.