Application of clay coating for water resistant corrugated packaging

Application of a delaminated kaolin clay base coat onto linerboard provides a barrier coating for a subsequently applied polymer top coat with potential advantages of increased paper stiffness, improved water resistance at reduced polymer overcoat. Motivated by coating material cost reduction, feasibility of the technique is demonstrated by applying a delaminated clay coating online followed by an acrylic overcoat and various properties of the resulting coated linerboard measured. Test boxes were made with commercially supplied treated specialty medium using a pilot single facer with modified carrier starch adhesive and manual double-backing. Stacking compression strength retention as affected by the coatings was evaluated after exposure of the various test containers to a high humidity ice-pack test. Results show that good performance of corrugated boxes can be achieved with linerboard facings having a kaolin base coating.