High-barrier composite film and production method thereof

Abstract

The invention discloses a high-barrier composite film which comprises a film body, wherein the film body is formed by sequentially compounding an LDPE (Low-Density Polyethylene) outer layer, a PVDC (Polyvinyl Dichloride) middle layer and an LDPE inner layer. The high-barrier composite film is produced by the following steps of: respectively adding LDPE, PVDC and LDPE resin particles into three extruder hoppers of a composite film blow molding unit in the proportion of 36 percent:28 percent:36 percent; heating to a melting state by an extruder melting section; collecting into an upper die head, a middle die head and a lower die head of a composite die head for compounding; and blow-molding, cooling for moulding, drawing and carrying out corona treatment to obtain a finished film product with the thickness of 0.09-0.18mm. The invention has the advantages that three materials are compounded into a three-layer film by three extruders of the composite film blow molding unit, the materials with different performance are mutually compounded together in the extruding process and laminated on characteristics, and the finished film has needed favorable characteristics.

Description

technical field [0001] The invention relates to the fields of food packaging films, industrial stretch films and the like, in particular to a high-barrier composite film used for food packaging, and also relates to a production method of the composite film. Background technique [0002] In plastic packaging materials used for food, safety and sanitation issues are closely related to the health of consumers. At present, the food packaging composite film produced in China uses the middle layer adhesive, and there will be a small amount of solvent residue during the composite process. When used as food packaging, it will cause the food in the package to produce peculiar smell and deteriorate the hygienic performance. How to minimize solvent residues in food packaging films, which can ensure product quality and reduce production costs, improve economic benefits, so that it not only meets the development of packaging materials industry, but also adapts to the requirements of food...

AI Technical Summary

Problems solved by technology

[0003] In order to meet the above requirements, some manufacturers have developed adhesive-free composite packaging films, such as BOPP (biaxially oriented polypropylene) / LDPE (high-pressure polyethylene) cast film, with a thickness of 0.04mm, which can be used for food packaging such as instant noodles. However, due to the high oxygen transmission rate and water vapor transmission rate of the film, it cannot meet the hygiene and safety requirements of some foods.

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