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Preparation and Measurement of Controlled‐Release SO 2 Fungicide Active Packaging at Room Temperature
Author(s) -
Xu Wencai,
Li Dongli,
Fu Yabo,
Wei Hua
Publication year - 2013
Publication title -
packaging technology and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 50
eISSN - 1099-1522
pISSN - 0894-3214
DOI - 10.1002/pts.2004
Subject(s) - materials science , polypropylene , polyethylene , fungicide , composite material , adhesive , layer (electronics) , ethylene vinyl acetate , polyethylene terephthalate , polymer , horticulture , copolymer , biology
In this work, we prepared a novel, three‐layer‐structure packaging film for keeping fruit fresh with a controllable‐release amount of SO 2 fungicide. The outer layer was composed of biaxially oriented polypropylene film. The middle layer, prepared by mixing polyurethane adhesive with sodium metabisulfite and calcium sulfite powder, was the generating layer for the SO 2 fungicide. The inner layer consisted of a blended film of ethylene vinyl acetate (EVA) and low‐density polyethylene. The water vapour transmission rate and oxygen transmission rate of the composite films, as well as the release amounts of SO 2 in all sealed packaging bags, were measured. Next, the controllable‐release mechanism of SO 2 fungicide was investigated, of which a preliminary discussion is included. The results of this experiment showed that the release amounts of SO 2 in packaging bags were controlled by the additional amount of EVA resin contained in the inner layers. The more EVA resin added to the inner layer, the more SO 2 fungicide was produced. Inside the packaging, SO 2 was released continuously for approximately 50 days at room temperature (25º ± 1°C). SO 2 concentrations ranged from 10 to 40 ppm in the freshness‐preserving packaging bags, effectively retarding mould growth and keeping the fruits fresh. Copyright © 2012 John Wiley & Sons, Ltd.