Fundamental study on barrier coating of paper with nano-cellulose

Abstract

In the present study, we performed a fundamental investigation of barrier coating the paper with CNFs made from bleached kraft pulps irradiated by electron beam. Barrier coating was performed by impregnating no-sizing base paper with CNF and alkyl ketene dimer (AKD) mixture, the latter often being used as an internal sizing agent. The hydrophobicity and air permeability of the barrier-coated paper were measured, and the surface of the coated paper was also observed by electron micrograph. The base paper was twice impregnated with the CNF and AKD mixture to achieve the desired weight. Paper coated with CNF-only slurry showed poor water resistance due to the hydrophilicity of the CNFs. However, the addition of AKD improved the contact angle and decreased the degree of Cobb size. So, hydrophobic CNFs must be used, or other hydrophobic materials together with standard CNFs. The barrier coating dramatically decreased the air permeability of the paper and the CNFs made from bleached kraft pulps irradiated by electron beam were the most effective in this regard. It was therefore concluded that barrier coating with a CNF and hydrophobic material mixture simultaneously improves the coated paper's resistance to the water absorption and air permeability. ? 2015 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.