Preparation method of black low-gloss polyimide film

Abstract

The invention provides a preparation method of a black low-gloss polyimide film. The preparation method comprises main steps as follows: I, a polyimide acid resin solution is prepared with a conventional method; II, black slurry is prepared, and the amount of black pigment is 2wt%-20wt% of solid content M of the polyimide acid resin solution; III, a delustering agent dispersing solution is prepared, and the quantity of the delustering agent is 2wt%-20wt% of M; IV, a black polyimide acid resin solution is prepared, and the polyimide acid resin solution, the black slurry, the delustering agent dispersing solution and an agglomeration solution are blended, stirred and defoamed for standby application; V, the black polyimide acid resin solution passes through a filter system and a conveying pipe and is subjected to magnetic field or ultrasonic treatment, magnetic field or ultrasonic agglomeration treatment of the resin solution is completed, and then the black low-gloss polyimide film is prepared conventionally. According to the preparation method, average grain diameter of the black pigment and the delustering agent is 0.01-0.8 mu m, besides, the agglomeration solution is added in thepolycondensation synthesis process of polyamide acid resin, and light transmittance, glossiness and physical and mechanical characteristics of the obtained 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 low gloss 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 visio...

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 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 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 the defects of complex preparation process, high production control precision requirements and high manufacturing cost.

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