JPS6438460A - Packaging material - Google Patents

Abstract

PURPOSE:To obtain a packaging material which can maintain the freshness of perishable agricultural products for a long period of time, by forming a layer of a freshness- retentive agent containing, as its essential constituents, an ethylene absorbent, a highly water-absorptive resin, a salt of a polyvalent metal, and NaHSO3 on the surface of a packaging base material. CONSTITUTION:A packaging material is prepared by forming on the surface of its base a layer of a freshness-retentive agent containing, as its essential constituents, an ethylene absorbent (A) selected from a high-molecular complex made by coordination of CuCl and AlCl3 with a crosslinked PS, a high-molecular complex made by coordination of AgCl and AlCl3 with a crosslinked PS, a high-molecular complex made by coordination of cuCl with an ion exchange resin, an inorganic complex made by coordination of Cu<1+> ions with zeolite, an inorganic complex made by coordination of Cu<1+> ions with gamma-alumina, and an inorganic complex made by coordination of CuNO3 with activated carbon; a highly water-absorptive resin (B) (e.g., a crosslinked polyacrylic salt); a salt (C) of a polyvalent metal having a valence of 2 or higher and capable of having a valence lower that that (e.g., CuCl2); and NaHSO3 (D) which reduces said salt C in the presence of water to a salt of the metal having a reduced valence. This packaging material can absorb ethylene gas and is useful for maintaining the freshness of perishable agricultural products.