A kind of online coating type modified biaxially stretched polyester film and preparation method thereof

Abstract

The invention provides an online coating type modified biaxially stretched polyester film and its preparation method and application. The modified biaxially stretched polyester film is coated on one side or both sides of the polyester base film , the coating is obtained after the water-based coating liquid is coated on the surface of the polyester base film and then evaporated and dried. The water-based coating liquid includes water-based resins, curing agents, surfactants, chitosan, and functional additives, The water-soluble resin is obtained by copolymerizing the following monomers: vinylidene chloride, acrylic acid, alkyl (meth)acrylate, vinyl acetate and acrylic cellulose. The film provided by the invention has good barrier properties after aluminized, and is especially suitable for use as food packaging materials. At the same time, the adhesion between the film and the aluminum layer is high, and the peel strength is above 8.7N / 25mm. Due to the high fastness of the aluminum layer, even under high heat and high Dealumination will not occur under wet conditions, which greatly reduces fire safety hazards and harm to the human body, and has obvious environmental protection 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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