Polarizing film, pressure-sensitive-adhesive-layer-attached polarizing film, and image display device and method for continuously producing same

Patent metadata

Field	Value
Publication number	US-2018024283-A1
Application number	US-201615549788-A
Country	US
Kind code	A1
Filing date	Feb 9, 2016
Priority date	Feb 13, 2015
Publication date	Jan 25, 2018
Grant date	—

Abstract

The present invention pertains to a polarizing film having a transparent resin layer on at least one side of a polarizer containing a polyvinyl alcohol-based resin, wherein the transparent resin layer has a thickness of 0.2 μm or more and is formed from a layer-forming material containing a polyvinyl alcohol-based resin having a saponification degree of 96 mol % or more, and wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is less than 1 wt %. This polarizing film has crack-resistant properties, and can minimize degradation of the optical characteristics in a heating and humidifying test.

First claim

1 . A polarizing film having a transparent resin layer on at least one side of a polarizer containing a polyvinyl alcohol-based resin, wherein the transparent resin layer has a thickness of 0.2 μm or more and is formed from a layer-forming material containing a polyvinyl alcohol-based resin having a saponification degree of 96 mol % or more, and wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is less than 1 wt %.

2 . The polarizing film according to claim 1 , wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is 0.5 wt % or less.

3 . The polarizing film according to claim 1 , wherein the combined total content of sodium acetate and potassium acetate contained in the transparent resin layer is 0.3 wt % or less.

4 . The polarizing film according to claim 1 , wherein the polyvinyl alcohol-based resin in the transparent resin layer has a saponification degree of 99 mol % or more.

5 . The polarizing film according to claim 1 , wherein the polyvinyl alcohol-based resin in the transparent resin layer has a saponification degree of 99.5 mol % or more.

6 . The polarizing film according to claim 1 , wherein the polyvinyl alcohol-based resin in the transparent resin layer has an average polymerization degree of 2000 or more.

7 . The polarizing film according to claim 1 , wherein the transparent resin layer has a thickness of 0.4 μm or more.

8 . The polarizing film according to claim 1 wherein the transparent resin layer has a thickness of 6 μm or less.

9 . The polarizing film according to claim 1 , wherein the polarizer has a thickness of 15 μm or less.

10 . The polarizing film according to claim 1 , wherein the polarizer contains boric acid in an amount of 20 wt % or less based on the total amount of the polarizer.

11 . The polarizing film according to claim 1 , wherein the polarizer is designed to have a single-body transmittance T and a polarization degree P representing optical properties satisfying the condition of the following formula: P>-(10 0.929T−42.4 −1)×100 (provided that T<42.3) or P≧99.9 (provided that T≧42.3).

12 . The polarizing film according to claim 1 , which has a protective film.

13 . A pressure-sensitive-adhesive-layer-attached polarizing film having the polarizing film according to claim 1 and a pressure-sensitive adhesive layer.

14 . The pressure-sensitive-adhesive-layer-attached polarizing film according to claim 13 , wherein a separator is laminated on the pressure-sensitive adhesive layer.

15 . The pressure-sensitive-adhesive-layer-attached polarizing film according to claim 14 , which is in the form of a roll.

16 . An image display device having the polarizing film according to claim 1 .

17 . A method for continuously producing an image display device, the method comprising the steps of:
unwinding the pressure-sensitive-adhesive-layer-attached polarizing film from the roll of the pressure-sensitive-adhesive-layer-attached polarizing film according to claim 15 ; feeding the pressure-sensitive-adhesive-layer-attached polarizing film with the separator; and continuously bonding the pressure-sensitive-adhesive-layer-attached polarizing film to a surface of an image display panel with the pressure-sensitive adhesive layer interposed therebetween.

18 . An image display device having the pressure-sensitive-adhesive-layer-attached polarizing film according to claim 13 .

Assignees

• Nitto Denko Corp

Inventors

• Motegi Yusuke
• Mita Satoshi
• Ueno Tomonori
• Kishi Atsushi
• Xu Jingfan

Classifications

• G02B5/305 Primary

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

• B32B27/30

  comprising vinyl {(co)polymers; comprising acrylic (co)polymers} · CPC title

• B32B7/023

  Optical properties · CPC title

• B32B2307/42

  Polarizing, birefringent, filtering · CPC title

• G02F1/133528

  Polarisers · CPC title