Improved barrier properties of double dispersion coated liner

Abstract

A dispersion coating formula that can be applied by conventional coating techniques and with satisfactory barrier properties has been developed. This formulation uses recyclable materials and is a cost-competitive replacement for wax-based barrier coatings. The water vapour transmission rate (WVTR) has been measured at both low and high humidity. At low humidity (50% R.H., 23 ° C) the barrier coating shows a WVTR of ≈ 40 g/(m 2 day −1) for a single coat and ≈ 20 g/(m 2 day −1) for a double coat at a total coat weight of 12 g/m 2. A dual coating consisting of one barrier coat and one pigmented top coat meets the industrial criteria of a WVTR < 50 g/(m 2 day −1) at high humidity (95% R.H., 3.5 ° C). This coating combination has acceptable print quality. The mechanosorptive creep of the dispersion coated corrugated board was also reduced significantly, particularly at high and variable relative humidity. The new coating therefore creates the opportunity to save fibre, as well as transport fuel, by manufacturing lighter weight boxes that maintain performance under the cyclic humidity conditions commonly encountered in goods distribution chains, particularly in the horticultural industry.