Adhesive-free aluminium and plastic compounded polyethylene film and manufacturing method thereof

Abstract

The invention discloses an adhesive-free aluminium and plastic compounded polyethylene film and a manufacturing method thereof. The polyethylene film comprises an adhesive-free compounding layer contacting an external aluminium foil, a main body layer in the middle and an inner heat-sealing layer, wherein a gecko foot-like nano-array structure is arranged on the outer surface of the adhesive-freecompounding layer. The manufacturing method comprises the following steps of: firstly, uniformly mixing raw materials for manufacturing each layer respectively according to a formula; secondly, injecting a raw material mixture into an extruder and processing the mixture into a raw material melt; thirdly, filtering the raw material melt, distributing flow passages and extruding the raw material melt from a mould head to obtain a coextruded compound film billet and extending the film billet to obtain a semifinished product with corresponding thickness; fourthly, processing the nano-array structure on the adhesive-free compounding layer of the semifinished product by a nano stamping technology; and finally, cooling and performing corona treatment or flame treatment to obtain a finished product of the adhesive-free aluminium and plastic compounded polyethylene film. The polyethylene film has the advantages of strong early bonding force, high peeling strength, low cost and resource saving;and the manufacturing process is simple, safe and environment-friendly.

Description

technical field [0001] The invention belongs to the technical field of packaging materials and their preparation, and in particular relates to a packaging material for aluminum-plastic composite films and a preparation method thereof. Background technique [0002] In the process of modern commodity packaging, the packaging of some commodities (especially food and medicine) has strict requirements on the various properties of packaging materials, such as requiring packaging materials to be moisture-proof, waterproof, gas-barrier, light-proof, heat-resistant, and oil-resistant. , high temperature resistance, easy heat sealing, easy printing and so on. It is difficult for a single packaging material to meet multiple requirements. Therefore, in the production process of packaging materials, two or more packaging materials with different characteristics are often combined together, and their excellent comprehensive properties are used to achieve product packaging. requirements. ...

AI Technical Summary

Problems solved by technology

[0004] 1) Glue method: According to different lamination processes, it is divided into dry lamination and wet lamination. The so-called wet lamination is to apply the adhesive evenly on the aluminum foil or plastic film substrate, and then put the aluminum foil and plastic film on a certain Lamination under pressure, and then volatilize the solvent in the adhesive through an oven; and dry lamination refers to uniformly coating the adhesive on the aluminum foil or plastic film substrate, volatilizing the solvent in the adhesive through an oven, and then Compounding under a certain pressure; however, both dry compounding and wet compounding require the use of a large amount of organic solvents. According to statistics, about 40,000 tons of solvent-based adhesives are used for compounding packaging materials in China every year. Roughly estimated, The total consumption of organic solvents throughout the year is not less than 60,000 tons, but the glue that really plays a role in bonding is only more than 25,000 tons. Such a large amount of organic solvents are consumed every year, which first causes a serious resource drain. Waste is contrary to the resource-saving economic development model currently advocated; secondly, it also leads to a significant increase in the production cost of packaging companies. Based on the current price of about 8,000 yuan per ton of organic solvents, packaging companies across the country spend more on organic solvents every year. The amount spent is as high as 480 million yuan, and the cost of the adhesive alone will increase by more than 40% (compared to the method without organic solvents); in addition, a large amount of organic solvents with pungent odors are discharged , not only will cause a bad production environment, but may also stimulate the respiratory organs of the workshop staff and affect production safety. Even if all the organic solvents can be discharged outdoors, this will also pollute the atmospheric environment, which does not meet the current advocacy The concept of green and sustainable development; today, with more and more emphasis on low-carbon, health, safety and environmental protection, resource conservation and green ecology, the negative impact of consuming such a large amount of organic solvents has become more and more popular focus on;

[0005] 2) Solvent-free composite method: that is, there is no solvent in the adhesive, and the use of this method has no pollution to the environment. However, the initial adhesion of the composite product obtained by this method is extremely low, which cannot meet the actual use requirements;

[0006] 3) Pre-coating method: the hot melt adhesive is pre-coated on the film, and the film and aluminum foil are hot-pressed when used. This method can also use no solvent, but there are more processes and more costs.

[0007] In addition, the time dependence of the peel strength of the adhesive layer of the composite film for packaging prepared by the above-mentioned various existing methods is more obvious.

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