Method for producing polarizing film

• US 10,088,705 B2
• Filed: 09/29/2015
• Issued: 10/02/2018
• Est. Priority Date: 09/30/2014
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Miyai, Emi, Ikeshima, Kentaro, Omine, Toshiki, Mita, Satoshi, Kishi, Atsushi, Ueno, Tomonori
• Primary Examiner(s): Font, Frank
• Application Number:
  US15/515,885
• Publication Number:
  US 20170299919A1
• Time in Patent Office: 1,099 Days
• Field of Search: 35948701, 35948702, 359900, 349 96
• CPC Class Codes: B23B 27/00 Tools for turning or boring machines for drilling machines B23B51/00; Tools of a similar kind in general; Accessories therefor
• CPC Class Codes: B23B 37/00 Boring by making use of ultrasonic energy essentially using abrasive material B24B, e.g. B24B1/04
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2457/202 LCD, i.e. liquid crystal displays
• CPC Class Codes: B32B 27/00 Layered products comprising a layer of synthetic resin fibrous or filamentary layer made of a synthetic resin B32B5/02; particulate layer made of a synthetic resin B32B5/16; foamed layer made of a synthetic resin B32B5/18
• CPC Class Codes: B32B 38/10 Removing layers, or parts of layers, mechanically or chemically
• CPC Class Codes: C23C 16/509 using internal electrodes
• CPC Class Codes: G02B 1/11 Anti-reflection 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: G02F 1/133632 with refractive index ellipsoid inclined relative to the LC-layer surface
• CPC Class Codes: G02F 2413/10 with refractive index ellipsoid inclined, or tilted, relative to the LC-layer surface O plate

Abstract

A method for producing a polarizing film includes (1) preparing a laminate (a) which includes a carrier film and a polarizer with a thickness of 10 μm or less formed on one surface of the carrier film and contains a polyvinyl alcohol-based resin; (2) peeling off the carrier film from the laminate (a); and (3) applying a liquid material to a side of the laminate (a) from which the carrier film has been peeled off and then solidifying or curing the liquid material to form a transparent resin layer with a thickness of 0.2 μm or more, wherein the liquid material contains a resin component or a curable component capable of forming a resin layer. This production method enables the achievement of a polarizing film which is able to have satisfactory durability in a heated environment even in cases where a thin polarizer is used therefor.

Claims

1. A method for producing a polarizing film, the method comprising:

providing a laminate comprising a carrier film and a polarizer,

wherein the polarizer has a thickness of up to 10 μ

m,

wherein the polarizer is formed on one surface of the carrier film and the polarizer comprises a polyvinyl alcohol-based resin;

peeling off the carrier film from the laminate; and

then

applying a liquid material to a side of the polarizer from which the carrier film has been peeled off and then

solidifying the liquid material to form a transparent resin layer with a thickness of 0.2 μ

m or more,

wherein the liquid material contains a resin component dissolved or dispersed in water.

2. The method for producing a polarizing film according to claim 1, wherein the transparent resin layer has an 80°

C. compressive elastic modulus of 0.1 GPa or more.

3. The method for producing a polarizing film according to claim 1, wherein the liquid material is an aqueous solution containing a polyvinyl alcohol-based resin.

4. The method for producing a polarizing film according to claim 1, wherein the liquid material has a viscosity of up to 1,000 mPa·

s at 25°

C.

5. The method for producing a polarizing film according to claim 1, wherein in the providing step, the laminate is obtained by performing at least a stretching step and a dyeing step.

6. The method for producing a polarizing film according claim 1, further comprising forming a protective film on a polarizer side of the laminate,

wherein the polarizing film is a one-side-protected polarizing film having the protective film provided on only one side of the polarizer.

7. The method for producing a polarizing film according to claim 1, wherein the polarizer has a single-body transmittance T and a polarization degree P representing optical properties satisfying the condition of the following formula:

P>

−

(100.929T−

42.4−

1)×

100 (provided that T<

42.3) or P≥

99.9 (provided that T≥

42.3).

8. The method for producing a polarizing film according to claim 1, further comprising forming a pressure-sensitive adhesive layer on a side of the transparent resin layer.

9. The method for producing a polarizing film according to claim 1, further comprising:

forming a protective film on a polarizer side of the laminate, and

forming a pressure-sensitive adhesive layer on a side of the transparent resin layer,

wherein the polarizing film produced is a one-side-protected polarizing film having the protective film provided on only one side of the polarizer.

10. The method for producing a polarizing film according to claim 1, wherein the carrier film is a thermoplastic resin film and has a thickness of 20 to 200 μ

m.

11. The method for producing a polarizing film according to claim 1, wherein the polarizer has a thickness of 2 μ

m to 8 μ

m.

12. The method for producing a polarizing film according to claim 6, wherein the protective film is selected from the group consisting of polyester-based polymers, cellulose-based polymers, acryl-based polymers, styrene-based polymers, and polycarbonate-based polymers.