Ten-layer co-extrusion packaging film and production method thereof

Abstract

The invention discloses a ten-layer co-extrusion packaging film and a production method thereof. The film adopts a ten-layer co-extrusion laminated structure, wherein the bottom layer adhered to a packaged object is a waterproof air-permeable layer; the starting melting temperature of the bottom layer is not higher than that of other layers covering the bottom layer; the ten-layer structure comprises 6 to 9 waterproof air-permeable layers; adhering layers are clamped among the waterproof air-permeable layers; the total number of the adhering layers and the waterproof air-permeable layers is 10; or the ten-layer structure comprises 2 to 7 waterproof air-permeable layers and 1 to 6 oxygen-blocking layers; the total number of the waterproof air-permeable layers and the oxygen-blocking layers is 6 to 8; at least one oxygen-blocking layer is clamped between two waterproof air-permeable layers; an adhering layer is clamped between the adjacent oxygen-blocking layer and waterproof air-permeable layer; and the total number of the adhering layers, the waterproof air-permeable layers and the oxygen-blocking layers is 10. Compared with the traditional film, the packaging film has high flexibility in functional design of each layer of the film, and has optimal film structural design and outstanding comprehensive performance.

Description

technical field [0001] The invention relates to a packaging film, in particular to a ten-layer co-extruded packaging film and a production method thereof, belonging to the technical field of flexible packaging films. Background technique [0002] In recent years, with the improvement of people's living standards, food varieties have become more and more abundant, people's requirements for food quality have become higher and higher, and more and more diverse requirements have been put forward for food packaging materials, such as The packaging materials for packaging fruits and vegetables, fresh meat and other foods have water resistance and air permeability, and the packaging materials for packaging chilled fresh meat, soybean products and other foods have oxygen resistance, and are used for packaging milk powder, coffee and cheese and other fragrant foods The material has oxygen barrier and aroma barrier properties, and it is used for packaging cooked meat products, rice an...

AI Technical Summary

Problems solved by technology

[0006] However, the current multi-layer co-extrusion film has a defect in that the number of co-extrusion layers of the film is still low, mostly less than 9 layers, which is not conducive to the flexible design of the specific structure of each layer of the film, and the flexibility of film function adjustment is not enough; and , the low number of layers of the film is detrimental to the improvement of its barrier properties. For example, in the case of low layers, in order to increase the barrier effect, the thickness of the barrier layer must be increased, but it also brings about an increase in manufacturing costs.

In addition, for the multi-layer co-extruded film that has been developed so far, even if it can achieve a higher number of co-extruded layers, the functional configuration of each layer of the film is still defective.

For example, the high-barrier nine-layer co-extrusion blown film disclosed in the Chinese patent with the authorization number CN2799232Y has good barrier properties, mechanical properties and optical properties, but the film has an asymmetric structure between layers. In the process of co-extrusion blow molding under the same pressure, stress imbalance will inevitably occur due to the difference in material crystallization temperature and crystallization rate, which will directly lead to film curling; in addition, the mechanical strength of the film is low on the side that is attached to the packaged object. If the bottom layer is damaged due to accidental factors such as heat sealing or pulling during use, the barrier properties or other functions of the film will fail or be partially damaged

Another example is a seven-layer co-extruded anti-curling composite film disclosed in the Chinese patent with the authorization number CN1156361C, which is composed of a crystalline resin layer, an amorphous resin layer and an adhesive resin layer, and has a balanced bridge structure, which can be used to a certain extent. Overcome the defect of curling in the secondary processing of the co-extruded film, but the film also has the defect of low mechanical strength on the side that is attached to the packaged object

In addition, the currently developed co-extruded films with more layers have high haze, low transparency, and few additional functions.

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