Method for preparing matt black polyimide film

Abstract

The invention discloses a method for preparing a matt black polyimide film. The method comprises I, preparing a polyamic acid resin solution through a conventional method, II, preparing black slurry of which the use amount is 2-20 wt% the solid content M of the polyamic acid resin solution, III, preparing a matting agent dispersion liquid of which the use amount is 2-20wt% M, IV, preparing a black polyamic acid resin solution through blending the polyamic acid resin solution, the black slurry and the matting agent dispersion liquid through stirring, and carrying out defoaming for next use, and V, carrying out curtain coating, drawing, imidization and setting on the black polyamic acid resin solution through conventional processes, wherein after biaxial drawing, imidization or setting, thefilm is subjected to surface treatment at a high temperature of 640-800 DEG C for 5-120s so that the matt black polyimide film is obtained. The black pigment and the matting agent have moderate average particle sizes. In the resin solution curtain coating, the high temperature surface treatment is used. The film has improved light transmittance, gloss and physical and mechanical properties.

Description

technical field [0001] The invention relates to a polyimide film manufacturing technology, in particular to a method for preparing a matte black polyimide film. Background technique [0002] Flexible printed circuit board (FPC) is widely used in 3C products, optical lens modules, liquid crystal display (LCD) modules and solar cells and other products, and polyimide film (Polyimide Film, referred to as PI film) is often used as its substrate Or cover film material, due to the high surface flatness of the traditional PI film in the application process, the surface of the film reflects most of the incident light and produces high gloss. The high-gloss film surface has glare or astigmatism caused by light reflection, which causes visual discomfort and easily fatigues the eyes when watching for a long time. Especially for high-gloss PI film polyimide films with black, white, blue, red and other colors, the reflected light on the surface has a more significant impact on vision. ...

AI Technical Summary

Problems solved by technology

Since the chemical conversion temperature must exceed 250°C during the preparation of polyimide films, none of the above organic compounds can withstand temperatures of 250°C or higher.

When such organic compounds are added to the polyimide film as a matting agent, it will cause defects such as cracks or holes in the film, or uneven color spots due to uneven melting

[0009] At present, the main production technology of matte black PI film is divided into two categories: one is to add black pigment and matting agent filler to PI resin, and then undergo chemical imidization or thermal imidization to synthesize a film with low light transmittance and Low-gloss PI film, this method is easy to operate and the effect is obvious, but due to the addition of a large amount of fillers, the mechanical properties of the PI film are greatly reduced; the other is to coat one or both sides of the PI base film Coated with a PI film containing black pigment and matting effect

Though this kind of method can make polyimide film present desired black effect preferably, and can guarantee the certain mechanical performance of polyimide film, but the black resin of additional coating usually increases manufacturing process and cost, and Detrimental effect on the properties of polyimide film

In addition, polyimide films are prone to performance degradation when exposed to thermal stress due to the poor heat resistance of the resin coating layer

There are many patent applications related to the manufacture of low-gloss black polyimide films, but they are difficult to implement due to defects such as complex manufacturing processes, high production control precision requirements, and high manufacturing costs.

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