Polyimide film for preparing graphite film, high-thermal-conductivity graphite film prepared from polyimide film and preparation method thereof

Abstract

The invention discloses a polyimide film for preparing a graphite film. The polyimide film is prepared by performing film forming and thermal imidization on a polyacrylonitrile / polyamide acid solution, the invention further discloses a high-thermal-conductivity graphite film prepared from the polyimide film and a preparation method of the high-thermal-conductivity graphite film, and the preparation method comprises the following steps: S1, carbonizing the polyimide film at high temperature to obtain a polyimide carbonized film; and S2, carrying out high-temperature graphitization on the polyimide carbonized film to obtain the high-thermal-conductivity graphite film. According to the preparation method, the polyacrylonitrile / polyamide acid solution is adopted as a raw material, the polyimide film is prepared through a thermal imidization method, the graphite film can be prepared through over-carbonization and graphitization, and the prepared graphite film has high thermal conductivity, high strength, good appearance integrity and excellent performance.

Description

technical field [0001] The invention relates to the technical field of film preparation, in particular to a polyimide film used for preparing a graphite film, a high thermal conductivity graphite film prepared by the polyimide film and a preparation method thereof. Background technique [0002] In recent years, electronic products such as mobile phones and tablet computers have been continuously developed in the direction of miniaturization and thinning, and the assembly density of electronic components has increased sharply. In order to ensure that the equipment can work stably for a long time, the heat generated during Timely escape, which puts forward very high requirements on the heat dissipation efficiency of heat dissipation materials. [0003] Artificial graphite film is one of the most advanced heat dissipation materials developed and applied in recent years. It is a high thermal conductivity material with a multilayer graphene structure. The thermal conductivity of...

AI Technical Summary

Problems solved by technology

However, domestic enterprises generally use the thermal imidization method to prepare polyimide films. Because the polyimide films prepared by the thermal imidization method have low foaming efficiency or even no foaming at high temperature, even if they can be graphitized to obtain graphite film, also requires a higher graphitization temperature, and graphite film has disadvantages such as low thermal conductivity, poor appearance, and low strength.

[0006] Chinese patent CN106832923B catalyzes high-temperature foaming of the film by doping calcium-containing compounds in the polyimide film. Although this method can obtain a complete graphite film, the addition of inorganic substances will not only affect the appearance and strength of the graphite film. It will also reduce its thermal conductivity to a certain extent; Chinese patent CN107265451B has obtained a graphite film with high thermal conductivity and high strength by adding graphene oxide in polyamic acid solution, but it uses a chemical imidization method, which is not suitable for Thermal imidization equipment is widely used in China, and the market price of graphene oxide is relatively expensive, so it is difficult to apply in industrial production