# US 8,771,788 B2 · Conductive polymer film and polarizing plate using the same

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- Number: US 8,771,788 B2
- Document ID: US8771788B2
- Status: Granted
- Kind: B2
- Application number: 13/242,364
- Filed: 2011-09-23
- Published: 2012-01-12
- Granted: 2014-07-08
- Earliest claimed: 2003-08-22
- Assignees: Nitto Denko Corporation
- Applicants: Hironobu Shinohara
- Inventors: Hironobu Shinohara
- Web page: https://patentgrep.com/patent/US8771788B2

## CPC

- B32B 27/286: {comprising polysulphones; polysulfides}
- B32B 23/08: of synthetic resin
- B32B 27/28: comprising synthetic resins not wholly covered by any one of the sub-groups {B32B27/30 - B32B27/42}
- B32B 2307/202: Conductive
- B32B 2307/21: Anti-static
- B32B 2307/212: Electromagnetic interference shielding
- B32B 2307/412: Transparent
- B32B 2307/42: Polarizing, birefringent, filtering
- Y10T 428/265: 1 mil or less
- Y10T 428/31504: Composite [nonstructural laminate]
- Y10T 428/31971: Of carbohydrate
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## 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

### Claim 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 μm 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 2)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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.