Method for measuring the degree of crosslinking of pressure sensitive adhesive

Abstract

A method for measuring the degree of crosslinking of pressure sensitive adhesive. The method, having the advantages of simple steps and short measuring time, comprises immersing a transparent substrate coated with a pressure sensitive adhesive in a solvent. After a specific period, the haze of the transparent substrate is measured. The obtained haze is compared with a predetermined reference, thereby determining the degree of crosslinking of the pressure sensitive adhesive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of a conventional polarizing film showing the structure thereof.

FIG. 2 is a schematic diagram of the method for measuring the haze according to the invention.

FIGS. 3 and 4 are graphs plotting haze against gel fraction of the pressure sensitive adhesives as disclosed in Example 1.

FIG. 5 is a graph plotting haze against gel fraction of the pressure sensitive adhesive as disclosed in Example 3.

Claims

1. A method for measuring the degree of crosslinking of pressure sensitive adhesive, comprising: providing a transparent substrate coated with a pressure sensitive adhesive;immersing the transparent substrate in a solvent;measuring the haze of the transparent substrate; andcomparing the obtained haze with a predetermined reference, thereby concluding the degree of crosslinking of the pressure sensitive adhesive.

2. The method as claimed in claim 1, wherein the transparent substrate comprises substrate employed in LCD or transparent optical film.

3. The method as claimed in claim 1, wherein the transparent substrate is glass.

4. The method as claimed in claim 1, wherein the transparent substrate comprises triacetate cellulose film, release film, antireflection film, or polarizing film.

5. The method as claimed in claim 1, wherein the pressure sensitive adhesive comprises natural rubber pressure sensitive adhesive, synthetic rubber pressure sensitive adhesive, or alkene polymer pressure sensitive adhesive.

6. The method as claimed in claim 1, wherein the pressure sensitive adhesive is polyacrylate.

7. The method as claimed in claim 1, wherein the transparent substrate is immersed in the solvent for 2˜4 min.

8. The method as claimed in claim 1, wherein the solvent comprises alcohol, alkane, ether, or ester.

9. The method as claimed in claim 1, wherein the solvent comprises methanol, ethanol, n-propanol, i-propanol, n-butanol, n-hexane, ethyl ether, tetrahydrofuran, or ethyl acetate

10. The method as claimed in claim 1, wherein the predetermined reference indicates the relationship between haze and gel fraction.