Method for online coating and preparation of diffusion polyester film

Abstract

The invention relates to a method for online coating and preparation of a diffusion polyester film. In terms of mass percentage, 70%-90% of a water-based organic polymer microsphere dispersion liquid having different microsphere particle sizes is slowly added to 9.9%-29.99% of pure water or deionized water and evenly stirred, then 0.01%-0.1% of a surfactant is added and evenly stirred, and a water-based coating liquid with the solid content being 17.5%-27% is prepared; polyester masterbatch containing 0-0.01% of a silica slipping agent is fused by an extruding machine, then a thick sheet is extruded, drawing is performed after casting, and one or two surfaces of a polyester film longitudinally drawn by 2.8-3.5 times are evenly coated with the prepared water-based coating liquid; the coated film is subjected to transverse drawing, drying solidification and heat setting and then is cooled, pulled and wound, and the diffusion polyester film with the coating thickness being 3-5 mu m is prepared. The film has high optical performance requirements and few appearance defects, procedures are simple and environment-friendly, and the production cost is low.

Description

technical field [0001] The invention relates to a method for preparing a diffusion polyester film by online coating, and belongs to the technical field of optical polyester films. Background technique [0002] Biaxially oriented polyester film has been widely used in many fields because of its excellent optical properties, good dimensional stability, excellent machining performance and heat resistance, especially as an optical base film. After the subsequent coating, it is endowed with functions such as diffusion, reflection, and brightness enhancement, which play a pivotal role in the backlight module. [0003] The traditional diffused polyester film is made by off-line coating, that is, the polyester film manufacturer first produces the biaxially oriented polyester film, and the downstream customers unwind the cut polyester film and coat it with inorganic or organic microbes. ball, and finally wind up to obtain a diffused polyester film. However, in order to produce low-...

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned method of off-line coating diffusion polyester film has restrictions on the extrusion method of the base material, and at the same time, it is easy to cause friction due to the mechanical and environmental contact of the polyester film base material in the process of repeated winding, unwinding, slitting, and handling. Apparent defects such as scratches and pollution make the yield of finished products low in the production process

At the same time, due to the cumbersome process, the cost of final production of diffused polyester film is relatively high

Furthermore, the off-line coating liquid contains a large amount of solvents, and the solvents volatilize during the production process, which will cause a certain degree of impact on the current environment

[0005] In recent years, with the increasing competitive pressure in the polyester film industry, a small number of polyester film manufacturers have tried to produce by adding a certain proportion of inorganic or organic microspheres to the three layers or the surface layer of the film through three-layer co-extrusion. Diffused polyester film, but because the mechanical processing performance of the film is affected after adding the above fillers, it is difficult to coordinate the thickness specification and required optical properties of the final product, so it can only be used in low-end fields

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