Polarizer protective film, polarizing plate, and image display apparatus

• US 9,297,932 B2
• Filed: 02/27/2007
• Issued: 03/29/2016
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: Nippon Shokubai Company Limited, Nitto Denko Corporation
• Original Assignee: Nippon Shokubai Company Limited, Nitto Denko Corporation
• Inventors: Ueda, Ken-ichi, Otome, Shigeo, Nakata, Mie, Nakano, Yuuki
• Primary Examiner(s): Blackwell, Gwendolyn
• Assistant Examiner(s): Frost, Anthony J
• Application Number:
  US12/282,310
• Publication Number:
  US 20090067047A1
• Time in Patent Office: 3,318 Days
• Field of Search: 428/1.33, 428/1.54, 349/96, 349/122
• US Class Current: 1/1
• CPC Class Codes: B32B 2457/202 LCD, i.e. liquid crystal displays
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid

Abstract

Provided is a polarizer protective film, which has high heat resistance, high transparency, high optical characteristics, and high mechanical strength, and is excellent in adhesion with respect to a polarizer. Further, provided are a polarizing plate using such a polarizer protective film and a polarizer, which has high adhesion with respect to the polarizer protective film and the polarizer and is excellent in optical characteristics, and an image display apparatus of high quality using such a polarizing plate.

A polarizer protective film according to the present invention includes a (meth)acrylic resin having a lactone ring structure and core-shell type nanoparticles having a core layer made of a rubber polymer and a shell layer made of a glass polymer.

Claims

1. A polarizing plate, comprising:

a polarizer formed of a polyvinyl alcohol-based resin, a polarizer protective film and an easy adhesion layer and an adhesive layer between the polarizer protective film and the polarizer,

wherein the polarizer protective film comprises;

50 to 99% by weight of a (meth) acrylic resin having only a lactone ring structure as a ring structure with respect to the polarizer protective film; and

core-shell type nanoparticles having a core layer made of a rubber polymer and a shell layer made of a glass polymer;

wherein the rubber polymer comprises an alkyl(meth)acrylate;

wherein the glass polymer contains at least one monomer selected from an alkyl(meth)acrylate and an aromatic vinyl monomer; and

the lactone ring structure is represented by general formula (1);

2. The polarizing plate according to claim 1, wherein the core-shell type nanoparticles have a particle diameter of 1 to 1,000 nm.

3. The polarizing plate according to claim 1, wherein the adhesive layer is formed of a polyvinyl alcohol-based adhesive.

4. The polarizing plate according to claim 1, comprising a cellulose-based resin film on a side of the polarizer opposite to the polarizer protective film.

5. The polarizing plate according to claim 1, further comprising a pressure-sensitive adhesive layer as at least one of an outermost layer.

6. An image display apparatus comprising at least one polarizing plate according to claim 1.

7. The polarizing plate according to claim 1, wherein the glass transition temperature of the (meth)acrylic resin having a lactone ring structure is 115°

C. or higher.

8. The polarizing plate according to claim 1, wherein the glass transition temperature of the rubber polymer is −

60°

C. to 20°

C.

9. The polarizing plate according to claim 1, wherein the glass transition temperature of the glass polymer is 50°

C. to 140°

C.

10. The polarizing plate according to claim 1, wherein the core layer in the core-shell type nanoparticles has a content ratio of 30 to 95% by weight.

11. The polarizing plate according to claim 1, wherein the shell layer in the core-shell type nanoparticles has a content ratio of 5 to 70% by weight.

12. The polarizing plate according to claim 1 has a tear strength of 2.1 N/mm or more.

13. The polarizing plate according to claim 1 has a moisture permeability of up to 100 g/m²·

24 hr.