Thermal imidization method for polymide film

Abstract

The invention provides a thermal imidization method for a polymide film. The method comprises the following steps: spreading polyamic acid resin on the surface of a driving steel belt, and heating for drying the polyamic acid resin on the driving steel belt to form a polyamic acid film; respectively sticking and fixing the transverse two ends of the bottom of the dried polyamic acid film on two fixed devices which can synchronously move together with the film, wherein the polyamic acid film is longitudinally stretched by a film rolling force, so that the polyamic acid film, together with the fixed devices, passes through a high temperature imidization furnace so that the polyamic acid film is subjected to imidization so as to form the polymide film; and then separating the polymide film from the fixed steel belt. According to the invention, the polyamic acid film performs imidization treatment under the longitudinal and transverse bidirectional stretch, and the prepared film has good mechanical strength and good size stability; and the steel belt or metal disk is used as a transverse stretch device, equipment structure is simple and has a high reliability, and the bidirectionality of the film is good in identity.

Description

technical field [0001] The invention relates to the technical field of polyimide films, in particular to a polyimide film thermal imidization method used for industrial production of polyimide films. Background technique [0002] In the production process of polyimide film, thermal imidization is the main method of imidization of polyimide film. There are three methods currently used: [0003] The first method: one-way pulling method: pour polyamic acid resin on the steel belt, bake in an oven, and obtain a polyamic acid film after drying; pull the polyamic acid film in one direction (film winding direction) Under force, heat imidization treatment is carried out through a heat imidization furnace to obtain. Since the polyamic acid imidization process in this method is carried out under unidirectional pulling force, the polyamic acid film has good mechanical strength and dimensional stability in the pulling direction, and the size in the undrawing direction will become small...

AI Technical Summary

Problems solved by technology

This method is similar to method 2. Because the transverse direction of the polyamic acid film depends on the needles on the needle plate to fix the film, the pinholes will cause the film to be torn to a certain extent during thermal imidization, resulting in a certain degree of transverse dimension of the film. Shrunken, so the transverse mechanical strength and dimensional stability are poor

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