Alkenyl succinic anhydride (ASA)

Alkenyl succinic anhydride (ASA) was added to the agents that would increase the resistance of cellulose fibers to the adsorption of water under neutral/alkaline conditions (at pH's in the range of 7.5-8.5) in the 1960's by 0. Wurzburg and E. Mazzerella of the National Starch and Chemical Company [1]. The sodium salt of ASA can be complexed with alum in a similar manner to resin acids to size in acid papermaking. Furthermore, commercial ASA products are also being used in acid papermaking, pH 4.5-6.5, in the manufacture of recycle linerboard, fine paper, roofing and molded products. The development of ASA gave papermakers an alternative to AKD (alkyl ketene dimer), a product that had been developed by C. Weissgerber of Hercules Chemical Company [2]. Both materials are applied to cellulose fibers in the form of cationic dispersion prior to the fibers being formed into a web, pressed and dried. The two sizing agents have helped papermakers make the transition from acid papermaking using clay as the primary pigment to neutral/alkaline papermaking using calcium carbonate.