Composite membrane with air-adjusting fresh-keeping and microwave heating automatic pressure-adjusting package device and its production method

Abstract

The invention relates to a composite film for a packing device with controlled atmosphere fresh-keeping and microwave self-venting and a method for manufacturing the same. The composite film includes: a substrate film layer provided with a first group of micro-gap structure area of which the adjacent edges physically contacted to each other; a sealing film layer covering one side of the first group of micro-gap structure area, and connected to the substrate film layer having the first group of micro-gap structure area through an adhesive layer, and then forming a second group of micro-gap structure area along the thickness direction on the composite film integrating the sealing film layer, the adhesive layer and the substrate film layer. The composite film has the function for regulating the high-temperature and high steam pressure, and avoids the packing device from blasting during the heating process, and prolongs the fresh-keeping and storing time for fresh vegetable and fruit. Besides, the composite film can be directly put in to a microwave oven for heating and regulating, which can not generate the problem of dry and hard food caused by huge drain of high temperature steam.

Description

technical field [0001] The invention relates to a composite film and a manufacturing method for a modified atmosphere preservation and microwave self-venting packaging device, in particular to a composite film used in a variety of airtight fresh fruit and vegetable packaging boxes or bags, which can At the same time, it provides a composite film and a manufacturing method for a modified atmosphere fresh-keeping and microwave heating automatic pressure-regulating packaging device that can extend the fresh-keeping period and can be directly microwave-heated and has the function of automatically adjusting high-temperature and high-pressure hot steam during the heating process without the risk of gas explosion. Background technique [0002] In the early days, to prolong the freshness period of fruits and vegetables and maintain good quality, lowering the storage environment temperature was one way. Under the low temperature environment, it can reduce the metabolic rate of living...

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Problems solved by technology

[0005] Up to now, most of the modified atmosphere preservation applications of fruits and vegetables use air-permeable mixed polymer materials, adopt co-extrusion or blown bag manufacturing technology, or use T-die stretch stretch wave film technology to make air-permeable films. It is complex, and the oxygen permeability and carbon dioxide permeability required for the gas regulation of various fruits and vegetables cannot be applied in one package. More importantly, these materials with breathability and air permeability cannot provide the gas produced in a closed microwave heating environment. High-temperature, high-pressure hot steam has the function of adjusting the large air volume. The following materials are common air-permeable materials on the market, but they cannot withstand closed microwave heating and cooking. Currently, the more common products of vegetable and fruit packaging materials with special air-permeability film are:

[0006] 1.>Plastic raw materials are blended with an inorganic powder raw material, and after uniform mixing, they are extruded with a blown bag (Blown) or T-die and stretched with a single or two dimensional axial tenter (one or two dimensional axial tenter) to produce a breathable Permanent film materials, a common example is a method of uniformly blending inorganic material powder, such as calcium carbonate (CaCO3), titanium oxide (TiO2) or aluminum oxide (Al2O3), into an organic polymer material, such as polyethylene, and then extruding it into a Films, such as the technologies disclosed in U.S. Patent Nos. 3,679,540, 4,187390, 4,350,655, 4,466,931, 4,777,073 and 5,340,646, generally speaking, although this type of material has special gas permeability, it can achieve gas regulation packaging environment (Modified Atmosphere Packaging, MAP ) functional requirements, but there is no application condition for microwave direct heating under airtight packaging. Reasons: (1) The mechanical strength of the film material is weak

(2) The melting point of the material is low. Generally, the materials used are polyethylene or polypropylene with a low melting point. The degree of elongation should not be too high or the crystallinity of the material should not be too high when the solid content of the inorganic powder is mixed with a high ratio. Cracks during the stretching process, and the inorganic powder is also easy to fall

(3) It is often necessary to add other additives such as lubricants in the raw material formula. The added lubricants or the transfer of the above inorganic powders or contact with food will have a negative impact on the human body during the microwave cooking process. The lubricant additives such as wax components are in the During the microwave heating process, it also often causes unpleasant odors. The material itself has the disadvantages of weak mechanical strength and low melting point, so it cannot be used in the microwave heating process under airtight packaging, otherwise it will cause excessive odor during the continuous heating process. Risk of elongation and bursting

[0010] The above-mentioned air-permeable materials and manufacturing methods are all known technologies, but they are not suitable for the application of packaging materials with closed microwave heating and modified atmosphere preservation for articles, and more importantly, their manufacturing costs are very high.

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