Air-proof moisture-permeable freshness retaining composite film, manufacturing method and application

Abstract

The invention discloses an air-proof moisture-permeable freshness retaining composite film, a manufacturing method and application. The air-proof moisture-permeable freshness retaining composite filmis characterized in that a core layer of the air-proof moisture-permeable freshness retaining composite film is air-proof moisture-permeable plastic wrap, and the positive and negative sides of the air-proof moisture-permeable plastic wrap are thermally bonded with anti-bacteria and mildew-proof non-woven fabrics in a point-like mode to make the air-proof moisture-permeable freshness retaining composite film. The plastic wrap has the characteristics of being high in wet strength, air-proof, good in moisture-permeable permeability and good in flexibility. The air-proof moisture-permeable freshness retaining composite film is loaded on a fruit and vegetable box, oxygen in air is blocked from entering the fruit and vegetable box, emission of carbon dioxide produced by respiration of fruits and vegetables in the box is prevented, high concentration of the carbon dioxide in the fruit and vegetable box is achieved, and thus the effect for inhibiting aerobic respiration of the fruits and vegetables is achieved; and at the same time the air-proof moisture-permeable film can emit excessive water vapor produced by the respiration of the fruits and vegetables, moisture condensation in the fruit and vegetable box is prevented, and the effects of gas concentration regulating and moisture regulating and freshness retaining are achieved.

Description

technical field [0001] The present invention relates to the technical field of fresh-keeping of fruits and vegetables and the technical field of special paper, in particular to the technical field of production of an air-blocking, moisture-permeable and fresh-keeping composite film for fruits and vegetables in refrigerators or fruit and vegetable boxes. Background technique [0002] Fresh fruits and vegetables are fresh foods with high water content, and they can still continue to carry out life activities such as breathing and transpiration after picking. During the storage of fruits and vegetables, the consumption of water and nutrients is directly proportional to the intensity of respiration of fruits and vegetables. Losing water is equivalent to losing freshness and weight. Therefore, reducing water loss and inhibiting respiration are important links in fruit and vegetable storage. The methods are humidity-adjusted fresh-keeping and modified-atmosphere fresh-keeping. ...

AI Technical Summary

Problems solved by technology

Generally, "temperature-sensitive and moisture-permeable film" uses nylon or polyester as the base material, and its moisture permeability can respond to temperature, but it does not respond to changes in humidity. Therefore, when the relative humidity is above 90%, the temperature-sensitive and moisture-permeable film The film itself will generate condensation, especially when it is placed on the fruit and vegetable box of the refrigerator, and it is placed in a low-temperature environment, it is also prone to condensation

Although the Siemens silicon filter membrane has moisturizing properties, its moisture permeability cannot change with temperature and humidity. The humidity in the fruit and vegetable box is as high as 100%, and condensation is serious

"Moisture-sensitive and moisture-permeable film" is to apply viscose solution on the paper-based substrate, and obtain a moisture-sensitive and moisture-permeable film through sulfuric acid acid precipitation regeneration and a series of subsequent purification processes, although the moisture-permeable film produced by this method The wet film has the characteristic that the moisture permeability increases with the increase of humidity, but the preparation of the moisture-sensitive moisture-permeable film by this method has the following problems: the production process is complicated, the equipment investment is large, and toxic carbon disulfide and other gases are released during the production process. , environmental pressure is high

Another method is modified atmosphere packaging, which is divided into active modified atmosphere packaging and passive modified atmosphere packaging: active modified atmosphere packaging is filled with mixed gas according to the breathing speed of different fruits, but due to the complexity of the technology and the variety of packaging materials and The performance requirements are relatively high, and it has not been widely used in my country; passive modified atmosphere packaging, that is, wrapping fruits and vegetables with plastic film, reducing the oxygen content by means of the respiration of fruits and vegetables and adjusting the ratio of oxygen and carbon dioxide through the packaging exchange gas, so as to reduce the pollution of fruits and vegetables. aerobic respiration

However, because the plastic film is airtight and non-hydrophilic, it has the disadvantage of low moisture permeability, which leads to a large amount of condensation in the container; and the plastic film has a low thickness and poor strength. It is a disposable product, and there are problems such as waste plastics polluting the environment.

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