PRESSURE-SENSITIVE ADHESIVE OPTICAL FILM AND IMAGE DISPLAY

• US 20090324944A1
• Filed: 06/11/2007
• Published: 12/31/2009
• Est. Priority Date: 06/28/2006
• Status: Abandoned Application

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Toyama, Yuusuke, Satake, Masayuki, Niino, Teppei
• Application Number:
  US12/304,817
• Publication Number:
  US 20090324944A1
• Time in Patent Office: Days
• US Class Current: 428/355.00R
• CPC Class Codes: C09J 133/04 Homopolymers or copolymers of esters C09J143/04 takes precedence
• CPC Class Codes: C09J 5/00 Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
• CPC Class Codes: C09J 7/385 Acrylic polymers
• 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
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2852 Adhesive compositions

Abstract

A pressure-sensitive adhesive optical film of the present invention comprises: an optical film; and a pressure-sensitive adhesive layer placed on at least one side of the optical film, wherein the pressure-sensitive adhesive layer has an equilibrium moisture content ratio (a) of 0.5% by weight or less, the pressure-sensitive adhesive layer shows a displacement amount (b) of 600 μm or less in one hour at 23° C., when a tensile shearing stress of 500 gf is applied to an adhesion area of 10 mm×10 mm having a thickness of 25 μm, and the equilibrium moisture content ratio (a) and the displacement amount (b) satisfy the relation: b<1036.4×e^−5.124a. The pressure-sensitive adhesive optical film can have high durability in high-temperature environments and be prevented from foaming in such environments, even when the optical film on which the pressure-sensitive adhesive layer is placed is made of a material with low moisture permeability.

Claims

1. A pressure-sensitive adhesive optical film, comprising:

an optical film; and

a pressure-sensitive adhesive layer placed on at least one side of the optical film, wherein

the pressure-sensitive adhesive layer has an equilibrium moisture content ratio (a) of 0.5% by weight or less,

the pressure-sensitive adhesive layer shows a displacement amount (b) of 600 μ

m or less in one hour at 23°

C., when a tensile shearing stress of 500 gf is applied to an adhesion area of 10 mm×

10 mm having a thickness of 25 μ

m, and

the equilibrium moisture content ratio (a) and the displacement amount (b) satisfy the relation;

b<

1036.4×

e<sup>−

5.124a</sup>.

2. The pressure-sensitive adhesive optical film according to claim 1, wherein the equilibrium moisture content ratio (a) is 0.02% by weight or more, and the displacement amount (b) is 20 μ

m or more.

3. The pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive layer has an equilibrium moisture content ratio (a) of 0.15% by weight or less and shows a displacement amount (b) of 600 μ

m or less.

4. The pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive layer has an equilibrium moisture content ratio (a) of more than 0.15% by weight to 0.25% by weight and shows a displacement amount (b) of 350 μ

m or less.

5. The pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive layer has an equilibrium moisture content ratio (a) of more than 0.25% by weight to 0.5% by weight and shows a displacement amount (b) of 150 μ

m or less.

6. The pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive layer has an equilibrium moisture content ratio (a) of from 0.05% by weight to 0.25% by weight, and the equilibrium moisture content ratio (a) and the displacement amount (b) satisfy the relation:

b≦

−

541.67a+209.58.

7. The pressure-sensitive adhesive optical film according to claim 1, wherein the optical film on which the pressure-sensitive adhesive layer is placed has a water-vapor permeability of 1000 g/m² per 24 hours or less at 80°

C. and 90% R.H.

8. The pressure-sensitive adhesive optical film according to claim 1, wherein the optical film is a polarizing plate comprising a polarizer and a transparent protective film placed on at least one side of the polarizer.

9. The pressure-sensitive adhesive optical film according to claim 8, wherein the transparent protective film placed on at least one side has a water-vapor permeability of 1000 g/m² per 24 hours or less at 80°

C. and 90% R.H., and the pressure-sensitive adhesive layer is placed on the transparent protective film.

10. The pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive comprising an acrylic polymer and a crosslinking agent.

11. An image display device, comprising at least one piece of the pressure-sensitive adhesive optical film according to claim 1.