Process for producing polarizer, polarizer, polarizing plate, optical film, process for producing composite polarizing plate, composite polarizing plate, and image display device

Abstract

This invention provides a process for producing a polarizer which can simultaneously realize the contact of a liquid with a hydrophilic polymer film and stretching of the hydrophilic polymer film in the widthwise direction by a tenter method or the like, using a small and simple production apparatus. The production process comprising a widthwise direction stretching step of holding both ends in the widthwise direction of a hydrophilic polymer film (1), being continuously supplied, by holding means (2), allowing the holding means (2) to travel in the longitudinal direction of the film (1), bringing the film (1) into contact with a liquid, and further moving the holding means (2), which holds at least one side of both the ends of the film (1) in its widthwise direction, to the outer side of the film (1) in its widthwise direction to stretch the film (1) in its widthwise direction, and a dying step of dying the film (1) with a dichroic substance. In the widthwise direction stretching step, the contact of the liquid is carried out by at least one of spraying and coating of the liquid, and the widthwise direction stretching step is carried out in at least one of the dying step and another step different from the dying step.

Description

technical field [0001] The invention relates to a method for manufacturing a polarizer, a polarizer, a polarizer, an optical film, a method for manufacturing a composite polarizer, a composite polarizer and an image display device. Background technique [0002] Polarizers have been used in various liquid crystal display devices (LCDs) such as televisions, personal computers, and mobile phones. Generally, the polarizer is produced by dyeing and uniaxially stretching a polyvinyl alcohol (PVA) film. When the PVA film is uniaxially stretched, the dichroic substance adsorbed (dyed) on the PVA molecule is oriented, so it becomes a polarizer. [0003] In recent years, the use of LCDs for televisions has rapidly increased, and the size of screens has also increased. Accordingly, the size of the polarizer used in the television is also required to be increased. As a method of producing such a large polarizer, a method of stretching a PVA film by a tenter method has been proposed w...

AI Technical Summary

Problems solved by technology

Therefore, if the above-mentioned method is adopted, there is a tendency to increase the size of the manufacturing equipment

In addition, if the tenter method is used, the movement of the PVA film in the vertical direction is difficult from a structural point of view

Therefore, combining stretching by a tenter method and immersing the PVA film in a bath at the same time requires a very complicated structure.

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