Special paper-plastic composite film for keeping freshness of fruits and vegetables at room temperature

Abstract

The invention relates to a special environmentally-friendly fresh-keeping paper-plastic composite flexible packaging film for fruits and vegetables. The fresh-keeping packing film is made by adding a blocking layer, a germicide releasing layer and an adjusting layer between two paper-based layers; by changing the polarity and air permeability of the blocking layer and adjusting layer, the purpose of controllably releasing germicide is realized; and the film can release gas-phase germicide of 5-20 ppm for 30-90 days, has functions of water conservation, disinfection and ventilation, mainly plays the role of keeping freshness of the fruits and the vegetables at room temperature to extend the shelf lives of the fruits and the vegetables, and can be naturally degraded after being discarded, without any pollution to the environment.

Description

technical field [0001] The invention relates to a paper-plastic composite film for keeping fruits and vegetables fresh at normal temperature and a preparation method thereof. The paper-plastic composite film uses a paper base as a base film, and an adjustment layer, a bactericide release layer (adhesive layer), and a barrier layer are arranged between two layers of paper bases. It is prepared by a solvent-free composite method and has slow-release sterilization and water retention. , Breathable function, used for fresh-keeping of fruits and vegetables at room temperature. Background technique [0002] With the development of my country's urbanization process and the improvement of people's living standards, vegetables and fruits in big cities are increasingly dependent on external supply. From the place of origin to the hands of the people, they need to go through several stages of picking, gathering, long-distance transportation, wholesale, and supermarkets. Generally, it t...

AI Technical Summary

Problems solved by technology

[0004] 1 The existing fresh-keeping materials are mostly limited to plastic substrates, because the oxygen transmission rate (0TR) of general plastic substrates can only reach 10 4 ml / m 2 .day.atm cannot meet the metabolism requirements of fruits and vegetables at room temperature, and generally can only be used as fresh-keeping materials for fruits and vegetables at low temperatures, but the effect of keeping fruits and vegetables at room temperature is poor, and even at room temperature will cause anaerobic respiration of fruits and vegetables;

[0005] 2. The water vapor transmission rate (WVTR) of the existing plastic-based fresh-keeping materials is small, and the moisture generated by the metabolism of fruits and vegetables in the fresh-keeping bags is easy to form a high-humidity internal environment, causing bacteria to grow and accelerating the decay of fruits and vegetables;

[0006] 3 If the air permeability of plastic fresh-keeping packaging is increased, the thickness of the film needs to be reduced, which in turn brings about the problem of insufficient mechanical properties of the packaging, making it difficult to process the film and prepare fresh-keeping bags

[0007] In short, the respiration intensity of fruits and vegetables at room temperature is high, and the requirements for fresh-keeping packaging materials are high. The existing plastic-based fresh-keeping materials are generally only suitable for low temperature use, or only suitable for fruits and vegetables with low respiration intensity. For fruits and vegetables with high respiration intensity At room temperature, not only will it not play a role in preserving freshness, but it will accelerate the decay of fruits and vegetables

Images