Prevulcanized Natural Rubber Latex/Modified Lignin Dispersion for Water Vapour Barrier Coatings on Paperboard Packaging

Abstract:

Modified natural rubber latex can be used as paperboard barrier coating in order to replace unrecyclable wax coating material. Natural rubber latex (NRL) was prevucanized in different time interval and the efficiency of crosslinking were determined by swelling ratio test. Prevulcanized natural rubber latex (Pre-VNRL) was blended with modified lignin dispersion to decrease sticking tendency of the coatings. Particle size of lignin dispersion was reduced by Mannish reaction using octylamine which can increase hydrophobility in lignin. Compared with Pre-VNRL coating, a reduction of water vapour transition rate (WVTR) was observed in blendingcoated paper. Such moisture-barrier behaviour is attributable to a good compatibility of the nanosized modified lignin particles with rubber. The blocking (sticking) tendency decreased with the content increase of lignin due to stiffness of lignin.