The Research Of Gas Transmission Mechanism Around Micro-Perforated Package

With increasing higher living standards of people, the demands of vegetables fresh become more and more high. So the package of micro-perforated film is a good choice. Package performance of ordinary film could not satisfy demand of vegetables lowers respiration. It causes the reduction of vegetables shelves life. Micro-perforated film supply atmosphere around which can restrain respiration through adjusting every factor of micro-perforate. It extends vegetables shelves life. Micro-perforated film is an ideal choice by better properties and low processing costs.In this paper, the PP micro-perforated film which had been punched micro-perforated of different density and different position in the film of thickness of40μm and50μm with a certain distance (diameter of280μm).The gas permeability and moisture-penetrability of single micro-perforated PP film were measured. Linear regression equation was established about perforate density and gas permeability(O2、 CO2)of micro-perforated PP film, perforation density and moisture-penetrability of micro-perforated PP film. It researched and analysed gas transmission mechanism and Moisture permeability law of micro-perforated PP film of different density and different position. Micro-perforated PP film had made self-supporting bag which was used for packing broccoli. It changes density and position of micro-perforated of self-supporting bag and observes the change of gas content and humidity in the package, weight loss, ascorbic acid and chlorophyll of broccoli. Experiment samples were made sensory evalution test everyday. It has non-perforated film and non-perforated self-supporting bag as blank control in every experiment.The experiment result showed that different thickness of micro-perforated film affected gas permeability micro-perforated film. Perforation number and gas permeability of micro-perforated film, perforation number and coefficient of moisture permeability all accord to unary linear relationship when the thickness of film is certain. Micro-perforation’s position could not affect permeability of micro-perforated PP film. Different gas molecular diameter leads to difference of variation tendency of gas permeability between micro-perforation and non-perforated film. Micro-perforated PP film had made self-supporting bag which was used for packing broccoli. Density and position of micro-perforation all affect the content of oxygen, carbon dioxide and quality of broccoli. It turns low content of oxygen, high content of carbon dioxide and high content of ascorbic acid and chlorophyll of broccoli when PP40μ2micro-perforate on broccoli bud. It extends shelf life of broccoli. This paper introduced new thinking for further research of micro-perforated film because of research of micro-perforated film and micro-perforated self-supporting bag’s influencing factors.