JPS5978285A - Self-adhesive film - Google Patents

Abstract

PURPOSE:To provide a self-adhesive film which reduces entrapment of air in bonding operation, has good self-adhesive property and is suitable for optical applications, prepared by using as release film a synthetic resin film embossed to have continuous projecting lines. CONSTITUTION:The self-adhesive film consists of a release film, an adhesive layer and a base film. Used as release film is a synthetic resin film embossed to have continuous projecting lines in the height of 1-15mum. When the height of the projecting line is less than 1mum, no effect is obtained, while when it exceeds 15mum, it tends to give rise to problems in optical applications. The base film includes ultraviolet ray shielding film, thermic ray shielding film, color changeable film, polarized film, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive film, particularly an adhesive film suitable for optical applications.

Adhesive films conventionally used for optical applications consist of a base film, an adhesive layer, and a release film, and when used, the adhesive film is cut into a desired shape,
After peeling off the release film, it can be applied to the adherend.

A synthetic resin film with a generally smooth surface is used as the release film, and the adhesion surface of the adhesive layer is smooth, so if it is applied tightly to the adherend, it will create an optically good adhesion surface.
can get. However, in many cases, bonding has the disadvantage that air is drawn into the bonded surface unless the conditions are very appropriate, and it is extremely difficult to remove this air from the bonded surface.
It is t.

The present inventors applied an adhesive film to the original article (= 3) and conducted a thorough voltage test to find a method that would not involve air when attaching the film.
They discovered that a problem with conventional adhesive films was that the adhesive surface was too smooth, and after further research, they finally completed the present invention.

That is, the present invention provides a release film, an adhesive layer, and a base (4).
An adhesive film consisting of a continuous C1 peel 1 layer (the film has a height of 1 to 15 μI+) and is a synthetic φ1 resin film embossed in a convex line shape. 1) 4 servings.

The release film used in the present invention may be a synthetic resin film that is normally used as a film for peeling, and preferably has a release surface treated with silicone. In the present invention, it is essential that the entire surface of the peeled surface is embossed in a continuous convex line shape with a height of 1 to 15 μm and a width of 2 to 10 μm. This continuous convex line is transferred to the adhesive surface (also called the adhesive surface of the adhesive layer) to form four continuous lines. The presence of these concave lines (grooves) prevents air from being entrained during pasting, and makes it easy to remove any trapped air. If the height of this convex line is less than I μm, the effect will be weak and 15
μn], air remains on the adhesive (adhesive) surface and distortion occurs in the adhesive layer, causing problems when used for optical applications. Regarding the shape of the embossing, it is sufficient to form a continuous convex line, and specific examples thereof are shown in FIGS. 1 to 3. The line portion in the figure is a convex portion.

The adhesive used in the present invention may have any composition as long as it is a commonly used adhesive, but acrylic adhesives are preferred from the viewpoint of their optical properties.

The adhesive film of the present invention can be obtained by applying or laminating an adhesive onto a release film or a base film, and then pressing a base film or a release filter onto the film. At that time, in order to prevent bubbles from remaining in the viscous agent layer or from forming later, it is preferable that when heated at 100°C for 2 hours, the heating area should be 1 inch or less.
, It is desirable that it be sufficiently dried so that it is 5% or less. The thickness varies depending on the application and the height of the embossing, but 10 to 50 μm is usually sufficient.

The adhesive film of the present invention has good adhesion (adhesion) because there is no air curl Δ when it is applied! 1! l
This is preferable when used in the optical field.

Examples of crystal phase films used in the optical field include ultraviolet cut films, heat ray cut films, variable color films, and polarizing film tubes.Adhesive films made from these films are cut appropriately according to their use.
Used in sunglasses, anti-glare glasses, ultraviolet filters, etc. In polarizing film, it is a liquid crystal cell.

Further, the pressure-sensitive adhesive film of the present invention is particularly advantageous since there is little concern about the generation of bubbles even when used in applications where the film is exposed to high temperatures.

The present invention will be explained below with reference to Examples.

Reference example 1. (Manufacture of embossed release paper) A commercially available biaxially oriented polypropylene film (thickness: 100 .mu.In) was embossed at about 80.degree. C. using an embossing roll that produces an embossed pattern as shown in FIG. Further, a silicone resin release agent was applied thereon and baked to obtain a release film A having peak and valley heights of 8 μm on average.

On the other hand, using a biaxially stretched polyethylene terephthalate film with a thickness of 50 μm, it was embossed (approximately 120°C) to form an embossed pattern as shown in Fig. A 3 μm release film 13 was obtained. The heights of the peaks and valleys were measured using a Shokuki Type 1 surface roughness meter.

Example 1 Acrylic adhesive (-4, "Diabond 1" manufactured by Gawa Chemical) A- was applied to the embossed surface of the peeled 11 film 71 A.
672” (trademark, with 5% hardening agent added) in roll coke.
It was applied using a drying oven set at 90°C for about 15 minutes. The coating thickness after drying is 20P on average, 100℃×
The heating loss after 21 hours was 0.7%. This adhesive layer was bonded with a Mine-1-o-ler to obtain an adhesive polarizing film.

Peel off the release phynotom from this 6-viscosity film, and apply it to a commercially available liquid crystal cell (surface glass plate) via an adhesive layer.
Glue the edges with a heated suppression roll at ℃.

No air bubbles were observed at this adhesive interface, and no air bubbles were observed even after being left at 80°C for about one month. Yogawa Chemical 1 Diabond DA, -3294'' (trademark)
, hardening agent 2 addition) was applied with a roll bowl tar, 120
It was dried at ℃ for about 10 minutes. The average thickness of the dry layer is 30μ
For Il+, the heating loss at 100° C. for 2 hours was 03. On this adhesive layer side, the same commercially available polarizing film as in Example 1 was laminated with a suppression roll containing about 5% Ir to create an adhesive polarizing film.

After peeling off the release film from this adhesive film and adhering it to a commercially available liquid crystal cell using a suppression roll, there were no air bubbles present at the interface, and no air bubbles were observed even after being left at 80°C for about a month. child.

Comparative Example 1 A biaxially stretched P E i'' film sold by 7fj was used as a release film, and the same adhesive was applied in the same manner as in Example 1 while the surface was kept smooth. After drying, the same polarizing film was laminated to increase the adhesiveness. A polarizing film was created.

When the release film was peeled off from this adhesive film and it was similarly adhered to a liquid crystal cell, many Q1 and air bubbles remained on the adhesive surface. Also, the image of the donation on the LCD screen was unclear.

Figures 1 to 3 are partially enlarged views of an example of embossing of a release film. This shows that the line in the figure has a convex shape.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd. No. 1121　　　　　2　 V3 Re

Claims (1)

[Claims] An adhesive film consisting of a release film, an adhesive layer, and a base film, the release film having a height of 1 to 15 μm.
An adhesive film characterized in that it is a synthetic resin film embossed in a continuous convex line shape of m.