Effects of cationic surfactant as rewetting agent on paper absorbency and structures

Surfactants used as rewetting agents for paper manufacture have been seldom reported. In this work, a cationic surfactant was applied to paper made on the UMIST pilot paper machine to study its rewetting abilities. The result s indicate that the rewetting agent can significantly reduce the water abso rbency time (WAT) of paper products. The reduction in WAT is caused by the effect of both an increase in the pore size and an increase in the hydrophi licity of fibres produced by the surfactant. The proper concentration of th e surfactant is 0.2% (st on dried fibres) or less for the furnish used in t his work. Above 0.2%, no further decrease in WAT was observed. The optimal dosage of surfactant is related to the dosage needed to considerable increa se the average pore size and debonding effects.