Viscosity-increasing precoating film of biaxial tension

Abstract

The invention relates to a bidirectional stretched precoating film with increased viscosity and a processing technology thereof. The precoating film comprises a base material, a middle layer and a hot melt adhesive layer, and is characterized in that the base material is a bidirectional stretched polyester (BOPET) film or a bidirectional stretched polypropylene (BOPP) film, the middle layer is made from polyethylene imine (PEI), and the hot melt adhesive layer is a mixture consisting of ethylene-vinyl acetate (EVA) and ethylene-methyl acrylate copolymer (EMA). The bidirectional stretched precoating film with the increased viscosity is obtained by using an extruded compound production line to evenly coat and clad the middle layer and the hot melt adhesive layer on one surface of the base material in turn. Because the resin adopted by the hot melt adhesive layer of the precoating film is the mixture consisting of the ethylene-vinyl acetate (EVA) and the ethylene-methyl acrylate copolymer (EMA), the precoating film has far larger cohesive force to printed matters than the precoating film of which the hot melt adhesive is pure EVA, and can remarkably show the high cohesive force particularly to the printed matters containing silicone oil ink or the printed matters containing water-based ink.

Description

[0001] Field [0002] The invention relates to the technical field of printing and film coating, in particular to a biaxially stretched tackifying pre-coating film and its processing technology. Background technique [0003] Printed matter lamination is an important means of post-press processing, which determines the final value of printed products. The lamination process of printed matter refers to covering the paper printed matter with a plastic film, using an adhesive in the middle, and after heat and pressure treatment, the plastic film and paper are bonded together to form a paper / plastic composite. One of the most advanced surface decoration processing technology. It protects and decorates printed matter, and is widely used in the field of packaging and printing, such as the surface processing of book covers, brochures, maps, advertising gift bags, and high-end packaging boxes. The coating can be divided into two types: coating film and pre-coating film. [0004] Coa...

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Problems solved by technology

However, this technology directly uses benzene-containing solvents in the coating process, which brings three major disadvantages that cannot be overcome due to its own process:

[0005] (1) Environmental protection issues: due to the volatilization and overflow of the toxic substance benzene, it causes air pollution and brings great harm to the health of producers and users; at the same time, the harmful substances remaining in the film are harmful to the health of consumers. adverse effects

[0006] (2) Quality problems: Since benzene, a volatile substance, continues to overflow after the film coating process, it is easy to form air bubbles between the film and the paper, making the surface of the printed product foggy, affecting the smoothness, clarity and color vividness of the printed product ; Sometimes due to insufficient bonding strength, it even causes cracking, wrinkling and peeling

In addition, that is, the production equipment of the coating film has a low degree of automation, which reduces the yield of the film coating

[0007] (3) Safety issues: Since the solution contains benzene, a volatile organic solvent, it is easy to form a flammable and explosive gas atmosphere around the liquid tank, and the plastic substrate used generates static electricity during operation, causing fire hazards

There have been several accidents like this, ranging from shutdowns to stop production, to machine burns, plant collapses, and casualties

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