Conductive polymer film and polarizing plate using the same

• US 8,771,788 B2
• Filed: 09/23/2011
• Issued: 07/08/2014
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Shinohara, Hironobu
• Primary Examiner(s): Turocy, David
• Assistant Examiner(s): Miller, Michael G
• Application Number:
  US13/242,364
• Publication Number:
  US 20120009335A1
• Time in Patent Office: 1,019 Days
• Field of Search: 427160-169
• US Class Current: 427/163.1
• CPC Class Codes: B32B 23/08 of synthetic resin
• CPC Class Codes: B32B 2307/202 Conductive
• CPC Class Codes: B32B 2307/21 Anti-static
• CPC Class Codes: B32B 2307/212 Electromagnetic interference shielding
• CPC Class Codes: B32B 2307/412 Transparent
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 27/28 comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
• CPC Class Codes: B32B 27/286 comprising polysulphones; polysulfides
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31971 Of carbohydrate

Abstract

A conductive polymer film having an antistatic function and an electromagnetic wave shielding function, and also having excellent optical properties such as transparency even if the film is arranged in the interior of LCD. The conductive polymer film comprises a polymer film and a conductive polymer adhered to the surface thereof, wherein the conductive polymer comprises polythiophene or polythiophene derivatives, the polymer film comprises an acetyl cellulose material or a norbornene material, a layer of the conductive polymer has a thickness of 3 μm or less, and the conductive polymer film has a visible light transmission of 78% or more and a surface resistivity of 10³-10¹² Ω/square.

Claims

1. A method of producing a protective film for a polarizing plate comprising a polymer film and a conductive polymer layer adhered to the surface thereof:

comprising the steps of;

forming an aqueous coating liquid comprising a conductive polymer by mixing polythiophene or polythiophene derivatives with water, and

forming the conductive polymer layer with the aqueous coating liquid on the surface of the polymer film, wherein

the polymer film comprises a norbornene material,

the conductive polymer layer has a thickness of 3 μ

m or less,

the protective film has a visible light transmission of 78% or more and a surface resistivity of 10³-10¹² Ω

/square, and

a yellowness of the protective film is decreased rather than a yellowness of the polymer film comprising a norbornene material by the forming of the conductive polymer layer on the surface of the polymer film.

2. The method of producing a protective film for a polarizing plate according to claim 1, wherein the aqueous coating liquid is prepared by adding a dopant in an amount of 0.1-500 parts by weight to 100 parts by weight of the conductive polymer that is polythiophene or polythiophene derivatives.

3. The method of producing a protective film for a polarizing plate according to claim 1, wherein the aqueous coating liquid contains a composition comprising 1-95% by weight of the conductive polymer and 5-99% by weight of a binder resin.

4. The method of producing a protective film for a polarizing plate according to claim 2, wherein the aqueous coating liquid contains a composition comprising 1-95% by weight of the conductive polymer and 5-99% by weight of a binder resin.

5. The method of producing a protective film for a polarizing plate according to claim 1, wherein a solid concentration of the aqueous coating liquid is 0.1-30% by weight.

6. The method of producing a protective film for a polarizing plate according to claim 1, wherein the aqueous coating liquid contains a water-soluble solvent.