Method and device for improving thickness uniformity of polyamic acid film

Abstract

The invention relates to a method and device for improving the thickness uniformity of a polyamide acid film. According to the method, a cast gel-like semi-solidified polyamide acid resin liquid film is extruded one time or multiple times, and the content of a solvent in the liquid film during extrusion is 60 to 300 percent. The device is characterized in that 1 to 10 extruding molds are installed behind plenum chambers of a preheating area and a high-temperature area of a casting drying oven, and at most one set of extruding mold is installed between every two adjacent plenum chambers; each extruding mold is a roller-type mold or an annule-type mold; the length of an extruding roller of each roller-type mold is identical to the width of a cast steel band; the annule-type mold is an extruded steel band surrounding two rollers, and the width of the extruded steel band is identical to the width of the cast steel band; the linear velocity direction and the linear velocity of the cast steel band are identical to those on the surface of the extruding roller which is closest to the cast steel band or the surface of the extruded steel band which is closest to the cast steel band, and a gap between the cast steel band and the adjacent extruding roller or the adjacent extruded steel band is 90 to 100 percent of the thickness of the liquid film. By adopting the method and the device, the thickness uniformity of the polyamide acid resin film can be obviously improved, and the thickness uniformity and other indexes of a subsequent polyimide film can be improved.

Description

Technical field [0001] The invention relates to a manufacturing technology of a polyimide film, in particular to a method and a device for improving the thickness uniformity of a polyamic acid film. Background technique [0002] Polyimide film is a polymer material with high strength, high toughness, abrasion resistance, high temperature resistance, corrosion resistance and other excellent properties. It is widely used in the electrical and electronic industries, especially in the electronics industry, it is a variety of high-end electronic products The main basic insulation material. [0003] With the development trend of light, thin, short, small and high-reliability design of downstream electronic products, the polyimide film demanded by the market tends to be thinner, and higher requirements are put forward for its thickness uniformity. [0004] At present, the manufacture of polyimide film generally adopts the solution polycondensation method to synthesize the polyimide precurs...

AI Technical Summary

Problems solved by technology

[0005] After the existing polyamic acid solution is coated on the stainless steel endless steel belt, the polyamic acid resin liquid film is volatilized and solidified under the hot air treatment. Uneven distribution of heat and air volume, uneven solvent volatilization and curing, resulting in poor thickness uniformity of the self-supporting polyamic acid film peeled off after curing, resulting in large thickness tolerances of subsequent polyimide films, heavy color difference and other appearances The impact on the quality, and at the same time cause the film film roll to have poor appearance flatness

[0006] In order to improve the thickness uniformity of polyimide film and solve the appearance quality problems such as color difference caused by thickness uniformity, one of the existing methods is to use a metering pump to adjust the flow rate of the resin solution in the molding die. The adjustment of the metering pump is mainly through Adjusting the speed to control the constant flow rate can only improve the uniformity of the longitudinal thickness of the polyamic acid resin liquid film when it leaves the lip of the molding die, but cannot solve the problem of uniformity of the transverse thickness, let alone solve the problem of solvent volatilization during the curing process of the polyamic acid resin uneven problem

[0007] Another method to improve the thickness uniformity of polyimide film products is the online thickness detection feedback forming mold automatic adjustment, the thickness gauge and the liquid film forming mold coordinate with each other to control the bolt of the lip opening of the forming mold to improve the thickness of the polyimide film. The vertical and horizontal thickness of the resin liquid film is uniform, but the structure of this device is complicated, the adjustment is cumbersome, the maintenance is difficult, and the input cost is high

And also can not solve the problem of uneven solvent volatilization in the curing process of polyamic acid resin

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