Preparation method of black polyimide thin film with matte surface

Abstract

The invention provides a preparation method of a black polyimide thin film with a matte surface. The preparation method comprises the following main steps: I, preparing a polyamic acid resin solutionaccording to a conventional method; II, preparing black slurry, wherein the amount of a black pigment is 2 to 20 weight percent of solid content M in the polyamic acid resin solution; III, preparing ablack polyamic acid resin solution; blending and stirring the polyamic acid resin solution, the black slurry and an agglomeration agent, and de-foaming for later use; IV, after enabling the black polyamic acid solution to pass through a filtering system, treating a conveying pipeline through a magnetic field or ultrasonic waves; finishing magnetic field and ultrasonic agglomeration treatment on the resin solution; then conventionally preparing the black polyimide thin film with the matte surface. According to the preparation method provided by the invention, the average grain diameter of theblack pigment is 0.01 to 0.8mu m; the agglomeration agent is added in a polyamic acid resin condensation polymerization synthesis process; the light transmittance, the glossiness and the physical andmechanical properties of the thin film are remarkably improved.

Description

technical field [0001] The invention relates to a polyimide film manufacturing technology, in particular to a method for preparing a black polyimide film with a matte surface. 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 impa...

AI Technical Summary

Problems solved by technology

When the content is large, the problem of uneven dispersion of additives will also occur; adding a large amount of matting agent will also lead to deterioration of the performance of the polyimide film, easy to be brittle, and a large amount of additives are prone to sedimentation and agglomeration in the polyamic acid resin. It will also increase the production cost of the film

[0008] At present, the main production technology of black low-gloss 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 number of fillers, the mechanical properties of the PI film are greatly reduced; the other type is on one or both sides of the PI base film Apply a layer of PI film with 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

In the early days, some people tried to directly prepare black and low-gloss PI membranes by using pigments with micron-sized and large particle sizes, but the pigments with larger particles easily blocked the filtration system, resulting in the inability to continuously form membranes, so they had to give up trying

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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