A REVIEW OF PAPER SIZING USING ALKYL KETENE DIMER VERSUS ALKENYL SUCCINIC ANHYDRIDE

A critical comparison Is made of the sizing of paper with AKD versus A SA, the two predominant commercial alkaline sizing agents. Recent resu lts and conclusions in the literature are examined with regard to chem ical reactivity, emulsion characteristics, the effect of pH, alum, and alkalinity, fines content, and sizing reversion. The two compounds re present to some extent extremes in chemical reactivity and emulsion st ability. These considerations in turn determine to a significant exten t their use in papermaking as sizing agents. In general AKD is used fo r products requiring very high levels of liquid resistance, whereas AS A is more typically used in situations involving moderate degrees of s izing. However depending on other aspects of a specific situation, the se generalizations can be easily over-ruled.