JPH09178902A - Polarizing plate or retarder protection method - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a method for protecting a polarizing plate or a retardation plate, which can satisfactorily protect the polarizing plate or the retardation plate without entrainment of air or foreign matter. SOLUTION: A synthetic resin is dissolved in a solvent that does not dissolve or swell the surface layer portion of a polarizing plate or a retardation plate, and this resin solution is applied to the surface of the polarizing plate or the retardation plate to be protected, and then dried. The solvent is scattered to form a resin film.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for protecting the surface of a polarizing plate or a retardation plate.

[0002]

2. Description of the Related Art In order to protect a polarizing plate or a retardation plate,
A protect film (including a tape) is used, and it is attached to the surface of the polarizing plate or the retardation plate to be protected.

Examples of the protective tape include a laminated film of a slightly adhesive ethylene-vinyl acetate copolymer film and a polyolefin film, a resin film such as a polyester film having an adhesive layer on one side, and the like. It is used.

[0004]

All of the above protect films use a resin film once molded as a substrate,
Since a slight adhesive resin layer or a pressure-sensitive adhesive layer is formed on this, fish eyes are generated in these resin films, and the resin film, the slightly adhesive resin layer or the pressure-sensitive adhesive layer is inevitably thick. There is unevenness.

Therefore, when the protect film is attached to the surface of the polarizing plate or the retardation plate, air or the like is caught between the polarizing plate or the retardation plate and the protect film.
There are problems that wrinkles are generated and adhesion is poor, and the polarizing plate or the retardation plate is not sufficiently protected.

Further, since the resin film is liable to generate static electricity, when the resin film is attached to the surface of the polarizing plate or the retardation plate, static electricity is generated and foreign matter such as dust adheres to the protective film and the polarizing plate or the retardation film There is a problem that the appearance of the board is deteriorated. In particular, this problem is likely to occur in a retardation plate whose substrate is thin and soft.

In view of the above points, the present invention provides a method for protecting a polarizing plate or a retardation plate, which can protect the polarizing plate or the retardation plate satisfactorily without entrainment of air or inclusion of foreign matter. The purpose is to do.

[0008]

A method for protecting a polarizing plate or a retardation plate of the present invention is a method of dissolving a synthetic resin in a solvent which does not dissolve or swell the surface layer portion of the polarizing plate or the retardation plate, and polarizes the resin solution. It is characterized in that it is applied to the surface of the plate or retardation plate to be protected, dried, and the solvent is scattered to form a resin film.

In the present invention, examples of the synthetic resin used for forming the resin film as the protective layer include acrylamide and its derivatives, polyvinylpyrrolidone and its derivatives, polyvinyl alcohol and its derivatives and the like. Examples include sulfonic acid polyvinyl alcohol.

As the solvent of this synthetic resin, a solvent which does not dissolve or swell the surface layer of the polarizing plate or the retardation plate is used, and examples thereof include water and alcohols. Is ethanol.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described with reference to examples.

(Example) Sulfonic acid-modified polyvinyl alcohol (Goselan L-030) having a saponification degree of 50% or less
(1: Nippon Synthetic Chemical Industry Co., Ltd.) is dissolved in ethanol and 2
The resin solution was 0% by weight. This resin solution is applied to the surface of a polycarbonate retardation plate having a thickness of 60 μm by a comma coater so that the thickness of the resin film after drying becomes 60 μm, and dried at 80 ° C. to scatter ethanol, A resin film of sulfonic acid-modified polyvinyl alcohol was formed on the surface of the phase difference plate. In this retardation film protected by the sulfonic acid-modified polyvinyl alcohol resin layer, the resin film had a thickness of 60 ± 2 μm and had a good appearance with no foreign matter such as air entrapment and dust.

Comparative Example A two-layer film (thickness 0.06 mm) made of coextrusion and composed of a polyethylene layer and an ethylene-vinyl acetate copolymer layer was used as a protective tape, and a phase difference made of polycarbonate having a thickness of 60 μm was used. It was attached to the surface of the plate. 5k on this protect tape when pasting
When a tension of g / m or more was applied, the tape curled and became defective. Even when the tape was applied with a tension of 3 kg / m, the tension was weak and wrinkles were generated on the tape, which was not defective.

[0014]

As described above, the method for protecting a polarizing plate or a retardation plate of the present invention is such that a resin solution is applied to the surface of the polarizing plate or the retardation plate to be protected, dried, and the solvent is scattered. Therefore, as in the case of protecting with a protect film, unlike the case of pasting a resin film once molded, as a result of the resin film of the protective layer being directly formed on the surface of the polarizing plate or the retardation plate, The surface of the polarizing plate or the retardation plate can be well protected without the risk of air entrapment and the inclusion of foreign matter. Further, since the solvent used in the resin solution does not dissolve or swell the surface layer portion of the polarizing plate or the retardation plate, the coating of the resin solution does not damage the surface layer portion of the polarizing plate or the retardation plate.

Claims (1)

[Claims] 1. A synthetic resin is dissolved in a solvent that does not dissolve or swell the surface layer portion of a polarizing plate or a retardation plate, and this resin solution is applied to the surface of the polarizing plate or the retardation plate to be protected and dried. A method for protecting a polarizing plate or a retardation plate, which comprises forming a resin film by scattering a solvent.