Polarizing plate with polyethylene terephthalate film as protective film, and method for manufacturing same

• US 10,451,915 B2
• Filed: 05/22/2015
• Issued: 10/22/2019
• Est. Priority Date: 05/22/2014
• Status: Active Grant

• Current Assignee: Shanjin Optoelectronics Company Limited
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Nam, Sung Hyun, Nam, Seunghee, Rah, Kyun Il, Lee, Dae Woong
• Primary Examiner(s): Hon, Sophie
• Application Number:
  US15/113,709
• Publication Number:
  US 20170010494A1
• Time in Patent Office: 1,614 Days
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08L 25/04 Homopolymers or copolymers of styrene
• CPC Class Codes: C08L 33/04 Homopolymers or copolymers of esters C08L43/04 takes precedence
• CPC Class Codes: C09D 167/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C09D167/06 takes precedence
• CPC Class Codes: C09J 129/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: C09K 2323/05 Bonding or intermediate layer characterised by chemical composition, e.g. sealant or spacer
• CPC Class Codes: C09K 2323/057 Ester polymer, e.g. polycarbonate, polyacrylate or polyester
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133567 on the back side
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G02F 2413/01 Number of plates being 1
• CPC Class Codes: G02F 2413/05 Single plate on one side of the LC cell

Abstract

The present invention relates to a polarizing plate including a polyethylene terephthalate film and having an excellent optical property, and a method for manufacturing the same, and the polarizing plate of the present invention includes: a water-based adhesive layer, a primer layer, and a polyethylene terephthalate protection film sequentially provided on at least one surface of a polarizer, in which the water-based adhesive layer is formed by using a water-based adhesive including a polyvinyl alcohol-based resin and a glyoxalate crosslinking agent at a weight ratio of 100:5 to 100:50, and the primer layer is formed by using a primer composition including a polyester-based compound and an acryl-based compound.

Claims

1. A polarizing plate comprising:

a water-based adhesive layer, a primer layer, and a polyethylene terephthalate protection film sequentially provided on at least one surface of a polarizer,

wherein the water-based adhesive layer is applied to the at least one surface of the polarizer, and the primer layer is in contact with the polyethylene terephthalate protection film and the water-based adhesive layer,

wherein the polarizer is a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene vinyl acetate copolymer-partially saponified film, where molecular chains containing an iodine-based compound or a dichromatic polarizing material are aligned in a predetermined direction,

wherein the water-based adhesive layer is formed by using a water-based adhesive including a polyvinyl alcohol-based resin containing an acetoacetyl group, and a glyoxalate crosslinking agent at a weight ratio of 100;

5 to 100;

50, and the primer layer is formed by using a primer composition including a polyester-based compound, an acryl-based compound containing a (meth)acrylate group, and a styrene-based compound,

wherein the polyester-based compound is formed using a reaction of an aromatic polybasic acid component and a polyol at a main chain thereof,

wherein a weight ratio of the polyester-based compound and the acryl-based compound in the primer composition is 1;

9 to 9;

1, and

wherein a weight ratio of the acryl-based compound and the styrene-based compound in the primer composition is 3;

7 to 7;

3.

2. The polarizing plate of claim 1, wherein the polyethylene terephthalate protection film is a stretched polyethylene terephthalate film.

3. The polarizing plate of claim 2, wherein an in-plane retardation value of the stretched polyethylene terephthalate film is 4000 nm to 10000 nm.

4. The polarizing plate of claim 2, wherein the stretched polyethylene terephthalate film is provided on one surface of the polarizer, and a triacetyl cellulose film, a cycloolefin polymer film, a norbornene film, a polycarbonate film, an acryl film, or a polyethylene terephthalate film is provided on the other surface of the polarizer.

5. The polarizing plate of claim 4, wherein the triacetyl cellulose film is provided on the other surface of the polarizer.

6. The polarizing plate of claim 1, further comprising:

a low refraction coating layer on a surface of the polyethylene terephthalate protection film, which is opposite to a surface facing the primer layer.

7. An image display comprising:

the polarizing plate of claim 1.

8. A liquid crystal display comprising:

a liquid crystal display panel including an upper substrate, a lower substrate, and a liquid crystal cell interposed between the upper substrate and the lower substrate;

a backlight unit disposed at a lower portion of the lower substrate; and

the polarizing plate of claim 1 disposed between the liquid crystal display panel and the backlight unit.

9. The liquid crystal display of claim 8, wherein the polarizing plate includes a stretched polyethylene terephthalate film on one surface of the polarizer and a triacetyl cellulose film on the other surface of the polarizer, and the triacetyl cellulose film is disposed at a liquid crystal display panel side.

10. A method for manufacturing a polarizing plate, the method comprising:

disposing a polarizer and a polyethylene terephthalate protection film in parallel;

forming a water-based adhesive layer by using a water-based adhesive between the polarizer and the polyethylene terephthalate protection film;

forming a primer layer by using a primer composition between the polyethylene terephthalate protection film and the water-based adhesive layer; and

attaching the polyethylene terephthalate protection film onto at least one surface of the polarizer via the water-based adhesive layer and the primer layer;

wherein the water-based adhesive layer is applied to a surface of the polarizer, and the primer layer is in contact with the polyethylene terephthalate protection film and the water-based adhesive layer,

wherein the polarizer is a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene vinyl acetate copolymer-partially saponified film, where molecular chains containing an iodine-based compound or a dichromatic polarizing material are aligned in a predetermined direction,

wherein the water-based adhesive layer is formed by using a water-based adhesive including a polyvinyl alcohol-based resin containing an acetoacetyl group, and a glyoxalate crosslinking agent at a weight ratio of 100;

5 to 100;

50, and the primer layer is formed by using a primer composition including a polyester-based compound, an acryl-based compound containing a (meth)acrylate group, and a styrene-based compound,

wherein the polyester-based compound is formed using a reaction of an aromatic polybasic acid component and a polyol at a main chain thereof,

wherein a weight ratio of the polyester-based compound and the acryl-based compound in the primer composition is 1;

9 to 9;

1, and

wherein a weight ratio of the acryl-based compound and the styrene-based compound in the primer composition is 3;

7 to 7;

3.

11. The method of claim 10, wherein the polyethylene terephthalate protection film is a stretched polyethylene terephthalate film.

12. The method of claim 11, wherein an in-plane retardation value of the stretched polyethylene terephthalate film is 4000 nm to 10000 nm.

13. The method of claim 10, wherein the forming of the primer layer includes:

applying the primer composition including the polyester-based compound and the acryl-based compound between the polyethylene terephthalate protection film and the water-based adhesive layer; and

drying the primer composition at a temperature of 80°

C. or more.

14. The method of claim 10, wherein the attaching of the polyethylene terephthalate protection film onto at least one surface of the polarizer is performed by a method of laminating the polarizer and the polyethylene terephthalate protection film and then performing drying at a temperature of 20°

C. to 100°

C. to cure the water-based adhesive layer and the primer layer.