Method for producing polarizing plate and polarizing plate

Patent metadata

Field	Value
Publication number	US-9995853-B2
Application number	US-201515121532-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 27, 2014
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

A method for producing a polarizing plate is provided, which includes the steps of obtaining a laminated film by forming a polyvinyl alcohol-based resin layer on a surface of a substrate film, obtaining a stretched film by stretching the laminated film, obtaining a polarizing laminated film by forming a polarizing layer by dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye, bonding a protective film composed of a thermoplastic resin to a surface of the polarizing layer opposite to the substrate film with an adhesive layer being interposed, peeling off the substrate film, and forming a protective layer having a thickness not smaller than 3 μm and composed of a cured product of a photo-curable compound on a surface which appears as a result of peeling off of the substrate film.

First claim

The invention claimed is:

1. A method for producing a polarizing plate, the method comprising the steps of:
obtaining a laminated film by forming a polyvinyl alcohol-based resin layer on a surface of a substrate film;
obtaining a stretched film by stretching the laminated film;
obtaining a polarizing laminated film by forming a polarizing layer by dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye;
bonding a protective film composed of a thermoplastic resin to a surface of the polarizing layer opposite to the substrate film with an adhesive layer being interposed;
peeling off the substrate film; and
forming a protective layer on a surface which appears as a result of peeling off of the substrate film, the protective layer being composed of a cured product of a photo-curable compound and having a thickness not smaller than 3 μm,
wherein the surface which appears as a result of peeling off of the substrate film has arithmetic mean roughness Ra 1 exceeding 55 nm and the surface of the polarizing layer forming the polarizing laminated film opposite to the substrate film has arithmetic mean roughness Ra 2 not greater than 55 nm.

2. The method according to claim 1 , wherein the polarizing layer has a thickness not greater than 10 μm.

3. The method according to claim 1 , wherein the protective layer has a tensile elastic modulus at 80° C. not smaller than 1500 MPa.

4. The method according to claim 1 , further comprising the step of laminating a pressure-sensitive adhesive layer on an outer surface of the protective layer.

5. A method for producing a polarizing plate, the method comprising the steps of:
bonding a protective film composed of a thermoplastic resin to one surface of a polarizing layer with an adhesive layer being interposed; and
forming a protective layer on the other surface of the polarizing layer, the protective layer being composed of a cured product of a photo-curable compound and having a thickness not smaller than 3 μm,
arithmetic mean roughness Ra 1 ′ of a surface on which the protective layer is formed being greater than arithmetic mean roughness Ra 2 ′ of a surface of the polarizing layer to which the protective film is bonded,
wherein the arithmetic mean roughness Ra 1 ′ exceeds 55 nm and the arithmetic mean roughness Ra 2 ′ is not greater than 55 nm.

6. The method according to claim 5 , wherein the polarizing layer has a thickness not greater than 10 μm.

7. The method according to claim 5 , wherein the protective layer has a tensile elastic modulus at 80° C. not smaller than 1500 MPa.

8. The method according to claim 5 , further comprising the step of laminating a pressure-sensitive adhesive layer on an outer surface of the protective layer.

9. A polarizing plate comprising:
a polarizing layer having a thickness not greater than 10 μm;
a protective film disposed on one surface of the polarizing layer with an adhesive layer being interposed, the protective film being composed of a thermoplastic resin; and
a protective layer disposed on the other surface of the polarizing layer, the protective layer being composed of a cured product of a photo-curable compound and having a thickness not smaller than 3 μm,
wherein the arithmetic mean roughness Ra 1 ′ of a surface on which the protective layer is formed exceeds 55 nm and the arithmetic mean roughness Ra 2 ′ of a surface of the polarizing layer to which the protective film is bonded is not greater than 55 nm.

Assignees

• Sumitomo Chemical Co

Inventors

• Kunai Yuichiro

Classifications

• G02B1/10

  Optical coatings produced by application to, or surface treatment of, optical elements (G02B1/08 takes precedence) · CPC title

• B29K2995/0097

  Thickness · CPC title

• G02B1/14 Primary

  Protective coatings, e.g. hard coatings · CPC title

• G02B5/305 Primary

  including organic materials, e.g. polymeric layers · CPC title

• B29D11/00644

  polarizing · CPC title