Polarizing plate and optical member

• US 20030152718A1
• Filed: 02/08/2002
• Published: 08/14/2003
• Est. Priority Date: 11/29/1999
• Status: Abandoned Application

• Current Assignee: Eiji Hamamoto, Seiichi Kusumoto, Takashi Shouda, Youichirou Sugino
• Original Assignee: Eiji Hamamoto, Seiichi Kusumoto, Takashi Shouda, Youichirou Sugino
• Inventors: Sugino, Youichirou, Kusumoto, Seiichi, Shouda, Takashi, Hamamoto, Eiji
• Application Number:
  US10/071,301
• Publication Number:
  US 20030152718A1
• Time in Patent Office: Days
• US Class Current: 428/1.31
• CPC Class Codes: C09K 2323/031 Polarizer or dye
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer

Abstract

A durable polarizing plate having a transparent protective film that is difficult to peel off under an influence of humidity and heat is disclosed. Such a polarizing plate is provided by bonding a transparent protective film through an adhesive layer on at least one surface of a polyvinyl alcohol-based polarizing film containing a dichroic substance, and the adhesive layer includes a water-soluble crosslinking agent that can crosslink a vinyl alcohol-based polymer. The adhesive layer can further include a vinyl alcohol-based polymer.

Claims

1. A polarizing plate comprising a polyvinyl alcohol-based polarizing film containing a dichroic substance and a transparent protective film bonded to at least one surface of the polyvinyl alcohol-based polarizing film through an adhesive layer, wherein

the adhesive layer comprises a water-soluble crosslinking agent capable of crosslinking a vinyl alcohol-based polymer.

2. The polarizing plate according to claim 1, wherein the adhesive layer further comprises the vinyl alcohol-based polymer.

3. The polarizing plate according to claim 1, wherein the water-soluble crosslinking agent is selected from the group consisting of boric acid, borax, glutaraldehyde, melamine and oxalic acid.

4. The polarizing plate according to claim 1, wherein the transparent protective film comprises a polymer selected from the group consisting of an acetate-based resin, a polyester-based resin, a polyethersulfone-based resin, a polycarbonate-based resin, a polyamide-based resin, a polyimide-based resin, a polyolefine-based resin and an acrylic resin.

5. The polarizing plate according to claim 1, wherein the transparent protective film is a triacetylcellulose film having a saponified surface.

6. An optical member of a laminate made by providing at least one additional optical layer on a polarizing plate comprising a polyvinyl alcohol-based polarizing film containing a dichroic substance and a transparent protective film bonded to at least one surface of the polyvinyl alcohol-based polarizing film through an adhesive layer, wherein the adhesive layer comprises a water-soluble crosslinking agent capable of crosslinking a vinyl alcohol-based polymer, and wherein the additional optical layer is other than a polarizing layer.

7. The optical member according to claim 6, wherein the additional optical layer is at least one selected from the group consisting of a reflective layer, a semitransparent reflective layer, a brightness-enhanced plate and a retardation plate.

8. A liquid crystal display comprising a liquid crystal cell and a polarizing plate arranged on at least one surface of the liquid crystal cell, wherein the polarizing plate comprises a polyvinyl alcohol-based polarizing film containing a dichroic substance and a transparent protective film bonded to at least one surface of the polyvinyl alcohol-based polarizing film through an adhesive layer, where the adhesive layer comprises a water-soluble crosslinking agent capable of crosslinking a vinyl alcohol-based polymer.