Production method of polymer film and production apparatus of the same

Abstract

There is provided a casting drum having an outer peripheral surface provided with an electrical insulating layer. Direct-current high voltage is applied to an electrode bar disposed in an upstream side from a discharge port to discharge toward the casting drum. Bead is attracted to the charged casting drum by electrostatic attraction. Thereby, the adhesion between the bead and the casting drum is increased, and therefore the occurrence of phenomenon of air entrainment can be prevented. A wet film obtained by peeling a casting film from the casting drum is dried. Accordingly, it is possible to produce a film having few defects such as voids and high quality such as excellent smoothness at high speed and stably.

Description

field of invention [0001] The present invention relates to a method for producing a polymer film and a device for producing it. Background of the invention [0002] On the surface of the polarizer which is a main part of a liquid crystal display (LCD), polymers for optical use such as a protective film for protecting the surface of the polarizer, a retardation film for removing optical distortion of light, and an antireflection film are used membrane. According to the obvious demand expansion of LCD, the demand expansion of polymer film also increased. In the following explanation, a polymer film is referred to as a film, and a polymer film for optical use is referred to as an optical film. [0003] As a production method of a polymer film, a solution casting method and a melt extrusion method are commonly used. In the melt extrusion process, polymer pellets are heated and melted to be extruded through an extruder, thus producing a film. The melt extrusion method is exce...

AI Technical Summary

Problems solved by technology

[0006] However, according to Japanese Patent Unexamined Publication No. 2001-113544, since the electrodes are disposed near the flow channels while film formation continues, solvent vapor evaporated from the flow channels or additives adheres to the electrodes and destroys the electrodes, which makes it difficult to Applied voltage

Thus, in Japanese Patent Laid-Open Publication No. 2001-113544, a reduction in the effect of preventing air entrainment occurs

In addition, according to Japanese Patent Laid-Open No. 2002-103359, only the suction chamber or the like is not enough to prevent the occurrence of the air entrainment phenomenon, and in addition, since the film formation speed becomes fast, both ends of the flow path fluctuate and become unstable , and thus there arises the problem that the cast film may have poor smoothness

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