Preparation method of oxygen-permeable and moisture-permeable packaging film for keeping vegetables and fruits fresh

Abstract

The invention relates to a preparation method of an oxygen-permeable and moisture-permeable packaging film for keeping vegetables and fruits fresh. The method concretely comprises the following steps:crushing bleached pulp for later use; adding a potassium permanganate solution and the pulp into N,N-dimethyl acetamide, activating the mixture in an oil bath, and then carrying out squeezing treatment; dissolving anhydrous lithium chloride completely in the N,N-dimethyl acetamide, adding activated cellulose pulp, stirring under the condition of heating, stopping stirring until the solution is gelatinous, placing the product at the room temperature, and finally obtaining a transparent cellulose solution; preparing the cellulose solution into a membrane by using a membrane wiping method, rapidly dipping the membrane into an alcohol coagulation bath for coagulating, and washing the obtained membrane with deionized water; finally, carrying out plasticizing treatment on the membrane by usinga glycerine aqueous solution, and naturally cooling at the room temperature to obtain the packaging film. According to the preparation method, the packaging film is prepared from plant cellulose, so that great pressure on the environment is avoided; the cellulose packaging film prepared by means of the alcohol coagulation bath has a loosened internal structure, thus having good oxygen-permeable and moisture-permeable properties, and meeting the fresh-keeping demand of the vegetables and the fruits.

Description

technical field [0001] The invention relates to the field of packaging film preparation, in particular to a method for preparing an oxygen-permeable and moisture-permeable packaging film for keeping vegetables and fruits fresh. Background technique [0002] Fresh vegetables and fruits are fresh products with high water content, and they continue to undergo respiration and transpiration after harvesting. Vegetables and fruits are often stored in packaging films, so the barrier properties of packaging films have an important impact on the freshness of vegetables and fruits. If the barrier property is too strong, the moisture produced during the respiration and transpiration of vegetables and fruits cannot be discharged, which will accelerate the decay of vegetables and fruits, which is not conducive to their freshness. At present, packaging films often choose pore-forming agents to add to polymer materials to prepare porous films to improve oxygen and moisture permeability, b...

AI Technical Summary

Problems solved by technology

If the barrier property is too strong, the moisture produced during the respiration and transpiration of vegetables and fruits cannot be discharged, which will accelerate the decay of vegetables and fruits, which is not conducive to their freshness

At present, packaging films often choose pore-forming agents to add to polymer materials to prepare porous films to improve oxygen and moisture permeability, but traditional polymer materials will cause huge pressure on the environment.