Online-coated modified biaxially-oriented polyester film and preparation method therefor

Abstract

The invention provides an online-coated modified biaxially-oriented polyester film, a preparation method therefor and use of the online-coated modified biaxially-oriented polyester film. According tothe modified biaxially-oriented polyester film, a single face or both faces of a polyester base film have coatings, the coatings are obtained through coating surfaces of the polyester base film with aqueous coating liquid and then carrying out volatile drying, the aqueous coating liquid comprises water-soluble resin, a curing agent, a surfactant, chitosan and functional assistants, and the water-soluble resin is obtained through copolymerizing the following monomers: vinylidene chloride, acrylic acid, alkyl (meth)acrylate, vinyl acetate and acrylic cellulose. After aluminizing, the film provided by the invention is good in barrier property and is particularly suitable for serving as a food packaging material; meanwhile, the adhesive power between the film and an aluminum layer is high, thepeeling strength reaches 8.7N / 25mm or more; and due to high fastness of the aluminum layer, a dealuminizing phenomenon does not occur even if under high-heat high-humidity conditions, fire control potential safety hazards and harmfulness to human bodies are greatly reduced, and thus, the film has an obvious environment-friendly significance.

Description

technical field [0001] The invention belongs to the technical field of new materials, and specifically relates to a plastic film, more specifically to an online coating type modified biaxially stretched polyester film and a preparation method thereof. [0002] technical background [0003] Biaxially oriented polyester film (abbreviated as BOPET) has excellent comprehensive properties. It has high mechanical strength, good optical properties, wide service temperature, excellent barrier properties, oil resistance, corrosion resistance, etc., so its application fields are very wide. The application of BOPET film in printing, compounding, vacuum aluminum plating and other aspects is the most common. In the field of packaging materials, BOPET film has low water absorption and good water resistance, and is suitable for packaging foods with high water content. BOPET is made of amorphous polyester chip PET, which is obtained through drying process, melt extrusion, casting, and verti...

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Problems solved by technology

[0005] However, the disadvantages of the coating method of competing products on the market: 1. The solvent coating used will have residues that are not safe for food packaging; 2. The surface relies on greatly increasing the coating tension to improve the adhesion of the aluminum plating, but due to the tightness of the two sides of the coating contact transfer

[0007] However, the methods in the above-mentioned patents all apply an aqueous emulsion of a certain resin material on the surface of the polyester base material. Specifically, the aqueous emulsion formed by forcibly dispersing the resin in water under the action of a surfactant is used as the coating layer. After coating, the water emulsion is unstable in the subsequent process, which will affect the performance of the obtained polyester film. In the subsequent vacuum aluminum plating of the obtained product BOPET, due to the low fastness of the aluminum layer, it may occur under high heat and high humidity conditions. Dealumination phenomenon, that is, the barrier performance of the material cannot be guaranteed. More importantly, it may have adverse effects on human health after dealumination. According to scientific research reports, aluminum may be harmful to the human body

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