PRESSURE-SENSITIVE ADHESIVE FOR POLARIZING PLATES, POLARIZING PLATE WITH PRESSURE-SENSITIVE ADHESIVE AND PRODUCTION PROCESS FOR THE SAME

Abstract

Provided are a pressure-sensitive adhesive for polarizing plates which can apply a polarizing plate on a liquid crystal cell with good adhesion and has the characteristic that a liquid crystal display device obtained therefrom is less liable to cause light leakage even under the environment of high temperature and high humidity and which has a removability and a polarizing plate with the above pressure-sensitive adhesive and a production process for the same.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is an outline drawing showing a constitution of LCD.

FIG. 2 is an outline drawing showing a constitution of LCD.

FIG. 3 is an explanatory drawing showing a method for evaluating a light leaking property of the polarizing plates provided with the pressure-sensitive adhesive obtained in the examples and the comparative examples.

Claims

1. A pressure-sensitive adhesive for polarizing plates, which is prepared by irradiating a pressure-sensitive adhesive material comprising (A) an acrylic base polymer comprising a monomer having a carboxyl group in a monomer composition ratio of 0.5 mass % or less and (B) an active energy beam-curable compound with an active energy beam and which has a storage elastic modulus (G′) of 0.3 MPa or more at 23° C.

2. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein the storage elastic modulus (G′) at 23° C. is 0.3 to 15 MPa.

3. The pressure-sensitive adhesive for polarizing plates as described in claim 1 or 2, wherein the storage elastic modulus (G′) at 80° C. is 0.3 MPa or more.

4. The pressure-sensitive adhesive for polarizing plates as described in claim 3, wherein the storage elastic modulus (G′) at 80° C. is 0.3 to 10 MPa.

5. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein it is used for applying a polarizing plate on a liquid crystal glass cell.

6. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein the active energy beam-curable compound of the component (B) is a multifunctional (meth)acrylate base monomer having a molecular weight of less than 1000.

7. The pressure-sensitive adhesive for polarizing plates as described in claim 6, wherein the multifunctional (meth)acrylate base monomer has a cyclic structure.

8. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein a content proportion of the component (A) to the component (B) is 100:1 to 100:100 in terms of a mass ratio.

9. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein the pressure-sensitive adhesive material further comprises (C) a cross-linking agent.

10. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein the pressure-sensitive adhesive material further comprises (D) a silane coupling agent.

11. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein an adhesive strength to non-alkali glass is 0.2 to 20 N/25 mm.

12. The pressure-sensitive adhesive for polarizing plates as described in claim 11, wherein a rise percentage of the adhesive strength to non-alkali glass after 168 hours pass since applied is 20% or less based on the initial value.

13. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein a maximum shear load at a distortion of 4000% or less in applying the polarizing plate on non-alkali glass at an applying area of 100 mm2 (10 mm×10 mm) and measuring a shear load at a shearing rate of 0.1 mm/minute is 70 N or less.

14. The pressure-sensitive adhesive for polarizing plates as described in claim 1, wherein a gel ratio is 85% or more.

15. A polarizing plate with a pressure-sensitive adhesive, characterized by having a layer comprising the pressure-sensitive adhesive as described in claim 1 on a polarizing plate.

16. A production process for the polarizing plate with the pressure-sensitive adhesive as described in claim 15, comprising applying a polarizing plate on a pressure-sensitive adhesive material layer provided on a release layer of a release sheet and then irradiating a release sheet side with an active energy beam.

17. A pressure-sensitive adhesive sheet prepared by interposing the pressure-sensitive adhesive for polarizing plates as described in claim 1 between two release sheets so that the pressure-sensitive adhesive is brought into contact with release layer sides of the release sheets.