Pressure-sensitive adhesive layer-attached polarizing film and image display

Abstract

A pressure-sensitive adhesive layer-attached polarizing film of the invention includes: a polarizing film; and a pressure-sensitive adhesive layer provided on the polarizing film, wherein the polarizing film includes a polarizer and a transparent protective film provided on only one side of the polarizer, the pressure-sensitive adhesive layer is provided on a side of the polarizer where the transparent protective film is absent, and the pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive composition containing a (meth)acryl-based polymer (A) and an alkali metal salt (B). The pressure-sensitive adhesive layer-attached polarizing film has a pressure-sensitive adhesive layer with an antistatic function and satisfactory durability and whose optical properties are less likely to be degraded.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. patent application Ser. No. 13 / 479,406 filed on May 24, 2012, which claims priority of Japanese patent application No. 2011-118334 filed on May 26, 2011, the entire content of each of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a pressure-sensitive adhesive layer-attached polarizing film having a polarizing film and a pressure-sensitive adhesive layer provided on the polarizing film. The present invention also relates to an image display, such as a liquid crystal display, an organic electroluminescence (EL) display, or a plasma display panel (PDP), produced using the pressure-sensitive adhesive layer-attached polarizing film.[0004]2. Description of the Related Art[0005]The image-forming system of liquid crystal displays or the like requires polarizing elements to be placed on both sides of a liquid crystal cell, ...

AI Technical Summary

Benefits of technology

[0035]If an ionic compound is added to a pressure-sensitive adhesive produced using an acryl-based polymer as a base polymer, an antistatic function can be provided to the pressure-sensitive adhesive. It is considered that in this case, the ionic compound can bleed out to the surface of the pressure-sensitive adhesive layer, so that the antistatic function can be efficiently produced. On the other hand, if the ionic compound comes into contact with a polarizer, its optical properties such as the degree of polarization may be degraded.

[0036]The pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached polarizing film of the present invention contains a (meth)acryl-based polymer (A)and an alkali metal salt (B) capable of providing an antistatic function, and the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition has a good antistatic function. It has also been found that when the alkali metal salt (B) is used according to the present invention, an antistatic function can be provided without degradation of a polarizer.

Problems solved by technology

Unfortunately, the pressure-sensitive adhesive layer-attached polarizing film has a problem in which when the pressure-sensitive adhesive layer contains an ionic compound for providing an antistatic function, the ionic compound in the pressure-sensitive adhesive layer can significantly affect the polarizer, so that, for example, when an ionic liquid or solid is used as the ionic compound, it may deteriorate the polarizer to significantly degrade the optical properties after a humidification test.

Also when a layer containing a conductive polymer such as polythiophene is provided between a polarizing film and a pressure-sensitive adhesive layer according to Patent Document 5, the polarizer and the optical properties will be deteriorated and degraded.

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