PACKAGING: III. EFFECT OF MOULD GROWTH AND AGEING ON THE WATER-VAPOUR TRANSMISSION OF PACKAGING MATERIALS

Abstract

Packaging materials were dusted with mould spores and stored in a cabinet at 95° F. and 95 to 100% relative humidity for periods of one to eight weeks.M.S.T. and M.S.A.T. "Cellophane" were attacked only slightly by mould, but deterioration of the heat-sealing, moisture-proof lacquer occurred during storage under conditions suitable for optimum mould growth. Moulds grew abundantly on M.S.Y.T. Cellophane. Wax-coated materials supported abundant mould growth, and their water-vapour transmission values increased when wax peeled from the surface of the sheet. The transmission rate of laminated materials having metal foil as one layer was not greatly affected by mould growth or delamination of the other layers. Abundant mould growth developed on most samples of kraft, and on glassine. Very little mould developed on cellulose acetate, Pliofilm, or vinyl-film.