PURPOSE: To obtain a coating composition to be applied to a base paper to form a moistureproof paper having excellent moistureproofness, folding resistance, deaggreation property, antiblocking property and the reusability of waste paper by using a wax emulsion and a water-soluble resin as main components.
CONSTITUTION: The objective water-based coating composition is composed mainly of (A) a wax emulsion containing paraffin wax, microcrystalline wax, etc., as a dispersoid and an emulsifier, a polyvinyl alcohol, etc., as a dispersing agent and (B) a water-soluble resin (preferably polyvinyl alcohol resin having a degree of polymerization of 200-3,000 and a saponification degree of ≥80mol%). The weight ratio (A/B) of the solid components is 25/75 to 80/20, preferably 35/65 to 80/20 and the solid concentration of the composition is preferably 5-50wt.%. The coating composition is applied to a base paper and dried with heat to obtain a coated paper having a thickness of ≤300μm and having a surface-coating layer consisting of the outermost layer composed mainly of wax and having a continuous wax layer and the innermost layer composed mainly of the component B.
MIYAZAKI HIROTOSHI
MARUYAMA HITOSHI