Stretched laminate, method of manufacturing thin polarizer, thin polarizer manufactured by the method, and polarizing plate including the thin polarizer

Patent metadata

Field	Value
Publication number	US-10081143-B2
Application number	US-201414387192-A
Country	US
Kind code	B2
Filing date	Jun 16, 2014
Priority date	Jun 18, 2013
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

There is provided a stretched laminate having superior optical characteristics, easily separable from a base film, and usable for manufacturing a thin polarizer. In addition, there are provided a method of manufacturing a thin polarizer having superior optical characteristics by using the stretched laminate, a thin polarizer manufactured by the method, and a polarizing plate including the thin polarizer.

First claim

The invention claimed is:

1. A stretched laminate formed by stretching a laminate comprising: a non-stretched polymer film; and a non-stretched polyvinyl alcohol-based film attached to at least one surface of the polymer film wherein the polymer film is a thermoplastic polyurethane film,
wherein both the polymer film and the polyvinyl alcohol-based film satisfy Formula 1 below in case of
x = film ⁢ ⁢ thickness ⁢ ⁢ after ⁢ ⁢ stretching film ⁢ ⁢ thickness ⁢ ⁢ before ⁢ ⁢ stretching ⁢ ⁢ and ⁢ ⁢ y = film ⁢ ⁢ width ⁢ ⁢ after ⁢ ⁢ stretching film ⁢ ⁢ width ⁢ ⁢ before ⁢ ⁢ stretching : y≤− 0.175 x+ 0.675  [Formula 1]

where 0.16≤x<1, and 0<y<1.

2. The stretched laminate of claim 1 , wherein both the polymer film and the polyvinyl alcohol-based film further satisfy Formula 2 below:
−1.350 x+ 0.830≤ y   [Formula 2]

where 0.16≤x<1, and 0<y<1.

3. The stretched laminate of claim 1 ,
wherein the laminate further comprises an adhesive layer between the non-stretched polymer film and the non-stretched polyvinyl alcohol-based film,
wherein an adhesive force between the polyvinyl alcohol-based film and the polymer film of the stretched laminate is 0.1 N/2 cm to 2 N/2 cm.

4. A method of manufacturing a thin polarizer, the method comprising:
forming a laminate by attaching a non-stretched polyvinyl alcohol-based film to at least one surface of a non-stretched polymer film, wherein the non-stretched polymer film is a thermoplastic polyurethane film; and
stretching the laminate such that both the polymer film and the polyvinyl alcohol-based film thickness after stretching film satisfy Formula 1 below in case of below in case of
x = film ⁢ ⁢ thickness ⁢ ⁢ after ⁢ ⁢ stretching film ⁢ ⁢ thickness ⁢ ⁢ before ⁢ ⁢ stretching ⁢ ⁢ and ⁢ ⁢ y = film ⁢ ⁢ width ⁢ ⁢ after ⁢ ⁢ stretching film ⁢ ⁢ width ⁢ ⁢ before ⁢ ⁢ stretching : y≤− 0.175 x+ 0.675  [Formula 1]

where 0.16≤x<1, and 0<y<1, and
wherein an adhesive force between the polyvinyl alcohol-based film and the polymer film of the stretched laminate is 0.1 N/2 cm to 2 N/2 cm.

5. The method of claim 4 , wherein the stretching of the laminate is performed such that both the polymer film and the polyvinyl alcohol-based film satisfy Formula 2 below:
0.350 x+ 0.830≤ y   [Formula 2]

where 0.16≤x<1, and 0<y<1.

6. The method of claim 4 , wherein the forming of the laminate comprises attaching the non-stretched polymer film and the non-stretched polyvinyl alcohol-based film to each other by using an adhesive.

7. The method of claim 4 , wherein the stretching of the laminate is performed such that the polyvinyl alcohol-based film has a thickness of 60 μm or less before the stretching and a thickness of 10 μm or less after the stretching.

8. The method of claim 4 , wherein the stretching of the laminate is performed within a temperature range of 20° C. to 80° C. at a stretching ratio of 5 times to 15 times.

9. The method of claim 4 , wherein the stretching of the laminate is performed in an aqueous boric acid solution having a boric acid content of 1 wt % to 5 wt %.

10. The method of claim 4 , wherein after the stretching of the laminate, an adhesive force between the stretched polyvinyl alcohol-based film and the stretched polymer film is 2 N/2 cm or less.

11. The method of claim 4 , wherein before the stretching of the laminate, the method further comprises dyeing the non-stretched polyvinyl alcohol-based film with one or more of iodine and a dichroic dye.

12. The method of claim 4 , wherein after the stretching of the laminate, the method further comprises separating the stretched polyvinyl alcohol-based film from the stretched polymer film.

13. The method of claim 12 , wherein the separating of the stretched polyvinyl alcohol-based film from the stretched polymer film is performed by applying peel force of 2 N/2 cm or less.

Assignees

• Lg Chemical Ltd

Inventors

• Nam Sung-Hyun
• Jung Jong-Hyun
• Rah Kyun-Ii
• Yu Hye-Min

Classifications

• B29K2105/256

  Sheets, plates, blanks or films · CPC title

• B29K2823/065

  HDPE, i.e. high density polyethylene · CPC title

• B32B2551/00

  Optical elements · CPC title

• B32B2307/42

  Polarizing, birefringent, filtering · CPC title

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title