JP2000105537A - Display front plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent production of bubbles over a long period even at high temperature dryness or high temperature high humidity by laminating a plastic film having a specified water vapor permeability on at least one side of a transparent resin substrate through a pressure sensitive adhesive layer. SOLUTION: This plasma display front plate is formed of a transparent resin substrate consisting of, for example, acrylic resin plate, polycarbonate resin plate or the like, which may have infrared ray shielding function, and a plastic film layered on one side or both sides thereof. The plastic film is needed to have a water vapor permeability of 10 g/m2/24 hr or more. The water vapor permeability is measured according to JIS X 0208. When the water vapor permeability is less than 10 g/m2/24 hr, bubbles are apt to be produced at high temperature dryness, and a water vapor permeability of 20 g/m2/24 hr or more is preferred. The water vapor permeability is generally 1,500 g/m2/24 hr or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a front panel for a display.

[0002]

2. Description of the Related Art A front panel for a display is a front panel used by being arranged on the front of a display device. Among display devices, among others, a plasma display device is useful as a large-sized display device.

The front panel used for such a plasma display functions not only as a protective plate for protecting the screen of the plasma display device, but also for adjusting the color tone of the display color, preventing the reflection of external light and preventing reflection. It also has various functions such as a function of shielding electromagnetic waves and infrared rays generated from the plasma display device. These functions are provided, for example, by laminating various functional plastic films that provide the above-described functions on one or both surfaces of a transparent substrate. A pressure-sensitive adhesive or the like is used.

On the other hand, a plasma display generates a large amount of heat compared with a conventional cathode ray tube (CRT) that generates a relatively large amount of heat. Therefore, a front panel used for the plasma display has a conventional CRT. Durability at higher temperatures is also required as compared with the front plate. Further, as a use of the plasma display, it is assumed that the plasma display is used in an open-air under a high temperature, for example, in a hot weather, a sauna, or the like.

However, when a transparent resin substrate is used as the transparent substrate, bubbles may easily be generated inside the front plate when used under high-temperature drying or high-temperature and high-humidity conditions. In the use of the plasma display device under various conditions, generation of air bubbles inside the front plate has been concerned.

In order to suppress the generation of such bubbles, a glass substrate may be used as the transparent substrate. However, there is a problem that the glass substrate is relatively weak to impact and tends to be heavy. When a transparent resin substrate is used as the transparent substrate, a hard coat layer may be provided on the surface of the transparent resin substrate to be used as a hard coat transparent resin substrate, and a functional plastic film may be bonded to one or both surfaces. Although it is conceivable, in addition to the extra step of providing the hard coat layer on the transparent resin substrate, there is a possibility that foreign matter may be mixed in the step of providing the hard coat layer, and it can not be said that it is sufficiently satisfactory. .

[0007]

SUMMARY OF THE INVENTION Accordingly, the present inventors have developed a plasma display front plate in which a plastic film is laminated on a transparent resin substrate via a pressure-sensitive adhesive layer under high-temperature drying and high-temperature and high-humidity conditions. As a result of intensive studies to develop a front panel for plasma display that is less likely to generate air bubbles even when used for a long period of time, a plastic film with a specific moisture permeability was added as a plastic film to impart functionality to the adhesive layer. The present inventors have found that the front plate bonded to the transparent substrate through the substrate does not easily generate bubbles over a long period of time even under high temperature drying and high temperature and high humidity, leading to the present invention.

[0008]

That is, the present invention relates to a front plate for a plasma display comprising a laminate in which a plastic film is laminated on at least one surface of a transparent resin substrate via a pressure-sensitive adhesive layer. Te, moisture permeability of the plastic film is one which provides a front plate, characterized in that at 10g / m ^2/24 hours or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As the transparent resin substrate applied to the front panel for a plasma display of the present invention, for example, an acrylic resin plate, a polycarbonate resin plate, a polyethylene terephthalate plate, a polyolefin resin plate made of polyethylene, polypropylene, etc. And the like. Although a hard coat layer may be provided on the surface of the transparent resin substrate, the effect of the present invention is remarkable when a transparent resin substrate having no hard coat layer is used. The transparent substrate may have, for example, an infrared shielding function of shielding infrared rays. The infrared ray shielding function can be provided by, for example, containing a compound that absorbs infrared rays. The thickness of the transparent resin substrate is not particularly limited, but is usually about 0.1 to 20 mm.

In the front plate for a plasma display of the present invention, a plastic film is laminated on one or both sides of such a transparent resin substrate via a pressure-sensitive adhesive layer, and the plastic film has a moisture permeability of 10 g / g.
It is required to be at m ^2/24 hours or more. Here, the moisture permeability is measured according to JIS Z 0208.

[0011] The moisture permeability tends bubbles are generated in the high temperature drying under is less than 10g / m ^2/24 hours, preferably 20g / m ^2/24 hours or more. Incidentally, such a moisture permeability is usually at most 1500g / m ^2/24 hours.

Such a plastic film has a function of adjusting the color tone of display colors, a function of preventing reflection of external light, a function of preventing reflection, a contamination-preventing layer for preventing contamination, and an electromagnetic wave for shielding electromagnetic waves generated from a plasma display. Various functions such as a shielding function and an infrared shielding function for shielding infrared rays generated from the plasma display are provided.

The color tone adjusting function can be provided by incorporating, for example, a dye or a pigment into a plastic film. The function of preventing reflection of external light can be provided, for example, by providing an antireflection film on the outer surface of the plastic film (the surface opposite to the side laminated on the transparent resin substrate). An antireflection film is a layer that can reduce the reflectance of visible light, for example, a thin film in which a layer made of a material having a low refractive index and a layer made of a material having a high refractive index are alternately laminated, For example, a thin film made of a substance and having a thickness of about 0.05 to 0.3 μm may be used. The reflection preventing function can be provided, for example, by providing fine irregularities on the outer surface of the plastic film. The anti-contamination layer is, for example, a substance capable of preventing the adhesion of contamination on the outer surface of the plastic film, for example, a fluorine-based coupling agent,
It can be provided by applying a coupling agent such as a silane coupling agent, followed by drying, and the coupling agent is usually applied after being diluted with a solvent.

The electromagnetic wave shielding layer can be provided by, for example, a method of providing a transparent conductive layer over one or both surfaces of a plastic film, or a method of providing a grid-like conductive layer. Examples of the transparent conductive layer include a layer made of indium-tin composite oxide (ITO), a thin film in which a conductive metal layer and a transparent high refractive index layer are alternately laminated, and the like. Examples of the conductive metal layer include silver and a layer containing silver as a main component. Examples of the grid-shaped conductive layer include a conductive thin film provided in a grid and a conductive mesh in which conductive fibers are woven in a grid. Examples of the infrared shielding function include a method in which a compound capable of absorbing infrared light is contained in a plastic film, and a method in which a layer that reflects infrared light is provided on one or both surfaces of the plastic film. Examples of the layer that reflects infrared rays include a layer made of silver.

One plastic film may be provided with one of these functions, or may be provided with two or more functions. For example, when a thin film in which silver or a conductive metal layer containing silver as a main component and a dielectric layer are alternately stacked is used as the electromagnetic wave shielding layer, the conductive metal layer reflects infrared light, A shielding function can also be provided.

The material of the plastic film is not particularly limited as long as it satisfies the above-mentioned moisture permeability and can be laminated on a transparent resin plate with a pressure-sensitive adhesive.
For example, a cellulose resin such as triacetyl cellulose (TAC), a polycarbonate resin (PC), a polyester resin such as polyethylene terephthalate (PET), an acrylic resin such as polymethyl methyl methacrylate (PMMA), polyethylene, polypropylene, etc. Polyolefin resins and the like can be mentioned. The thickness of the plastic film is appropriately selected within a range that satisfies the moisture permeability, and is not particularly limited, but is, for example, 10 μm to 300 μm.
It is about.

In the front panel for a display of the present invention, such a plastic film is laminated on a transparent resin substrate via a pressure-sensitive adhesive layer. Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer include an acrylic rare pressure-sensitive adhesive and a urethane-based pressure-sensitive adhesive. The thickness of the pressure-sensitive adhesive layer is not particularly limited,
Usually, it is about 10 to 200 μm.

The laminated plate used as the front plate for a plasma display of the present invention can be manufactured by, for example, providing a pressure-sensitive adhesive layer on one side of a plastic film and bonding the layer to a transparent resin substrate. Alternatively, a pressure-sensitive adhesive layer may be applied to the surface of the transparent resin substrate, and a plastic film may be laminated thereon. The bonding method is not particularly limited. For example, a transparent resin substrate having a predetermined size and a plastic film cut into a predetermined size may be overlapped with each other and then pressed, or a predetermined size may be applied. The transparent plastic substrate and the strip-shaped plastic film may be overlapped with each other and pressurized, and then the strip-shaped plastic film may be cut.

The laminate thus obtained is used as a front plate mounted on a front surface of a display device, particularly a plasma display device.

[0020]

The display front panel of the present invention is less likely to generate air bubbles for a long period of time even under high-temperature drying or high-temperature and high-humidity conditions. In addition, it has excellent long-term durability as a front plate that can be used for a plasma display that requires durability under high temperature and high humidity. Further, it can be used as a front plate of a display device used at high temperatures.

[0021]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The evaluation of the laminate obtained in each of the examples was performed by the following method. (1) Durability under High Temperature Drying After the laminate was left under drying at 80 ° C. for 120 hours, both sides of the laminate were visually observed, and evaluated according to the following criteria. ：: No generation of air bubbles was observed. Δ: Generation of air bubbles is observed in a part of the end. ×: Generation of air bubbles is observed at both the end and the center. (2) Durability under high temperature and high humidity After the laminate was left at 60 ° C. and 90% humidity for 120 hours, both sides of the laminate were visually observed, and evaluated according to the following criteria. ：: No generation of air bubbles was observed. Δ: Generation of air bubbles is observed in a part of the end. ×: Generation of air bubbles is observed at both the end and the center. (3) Moisture permeability of plastic film Measured according to JIS Z 0208.

Example 1 A transparent resin plate [Sx0000, manufactured by Sumitomo Chemical Co., Ltd.]
Acrylic resin plate, thickness 3mm, size 200mm × 3
00 mm, no hard coat layer on the surface] A TAC film [thickness: 139 μm] is provided with an anti-reflection layer on one side and a pressure-sensitive adhesive layer on the opposite side. Film ["Real Look 2201", manufactured by NOF CORPORATION, moisture permeability 234 g /
m ^2/24 hours, by laminating a 200 mm × 300 mm] size in pressure-sensitive adhesive layer side to obtain a laminate. Table 1 shows the evaluation results of the laminate. Even when this laminated plate is used as a front plate for a plasma display, which is disposed on the front surface of the plasma display, almost no bubbles are generated inside for a long period of time.

Example 2 The same transparent resin plate as used in Example 1 [“Sx000
0 ", a thickness of 3 mm, a size of 200 mm x 300 mm, and no hard coat layer on the surface].
201 ", a size of 200 mm x 300 mm] on the pressure-sensitive adhesive layer side, and a plastic film having an anti-glare function on the other surface [TAC having fine irregularities on the surface]
Film, thickness 84 .mu.m, moisture permeability 227g / m ^2/24
[Time] was laminated via an acrylic pressure-sensitive adhesive to obtain a laminate. Table 1 shows the evaluation results of the laminate. Even when this laminated plate is used as a front plate for a plasma display, which is disposed on the front surface of the plasma display, almost no bubbles are generated inside for a long period of time.

Example 3 The same transparent resin plate as used in Example 1 [“Sx000
0 ", thickness 3 mm, size 200 mm × 300 mm, no hard coat layer on the surface].
Film [thickness 23 .mu.m, moisture permeability 24g / m ^2/24 hours, 200 mm × 300 mm size] and laminated through an acrylic pressure sensitive adhesive, to obtain a laminate. Table 1 shows the evaluation results of the laminate. Even when this laminated plate is used as a front plate for a plasma display, which is disposed on the front surface of the plasma display, almost no bubbles are generated inside for a long period of time.

Example 4 Instead of a PET film, an acrylic resin film having a hard coat layer on one side [thickness 130 μm, moisture permeability 2
4g / m ^2/24 hours, size 200 mm × 300 meters
m], and the transparent resin plate (“Sx0000”) via an acrylic pressure-sensitive adhesive with the hard coat layer side facing out
A laminate is obtained in the same manner as in Example 3, except that the laminate is laminated. Even if this laminate is left under high temperature drying or high temperature and high humidity for a long time, almost no air bubbles are generated inside.
Also, even if this laminated plate is used as a front plate for a plasma display,
Almost no air bubbles are generated inside for a long time.

Example 5 Instead of a PET film, a polycarbonate resin film having a hard coat layer on one side [having a thickness of 129 μm,
Moisture permeability 29g / m ^2/24 hours, size 200 mm × 3
00 mm] and a transparent resin plate (“Sx000”) with the hard coat layer side outside through an acrylic pressure-sensitive adhesive.
0)), to obtain a laminate, operating in the same manner as in Example 3. Even if this laminate is left under high temperature drying or high temperature and high humidity for a long time, almost no air bubbles are generated inside. Further, even when this laminated plate is used as a front plate for a plasma display, which is disposed on the front surface of the plasma display, almost no bubbles are generated inside for a long period of time.

Comparative Example 1 The same transparent resin plate as used in Example 1 [“Sx000
0 ", a thickness of 3 mm, a size of 200 mm x 300 mm, and no hard coat layer on the surface].
201 ", having a size of 200 mm x 300 mm] on the pressure-sensitive adhesive layer side, and having a thin film in which a silver layer and an indium oxide layer are alternately laminated on one surface over the entire surface, thereby providing an electromagnetic wave shielding function. PET film having an infrared shielding function and [thickness 50 [mu] m, moisture permeability 0g / m ^2/24 hours, size 200 mm × 300 mm] was laminated via an acrylic pressure sensitive adhesive, to obtain a laminate. Table 1 shows the evaluation results of the laminate. If this laminate is used as a front panel for a plasma display for a long period of time when placed on the front of the plasma display, bubbles may be generated between the PET film and the transparent resin substrate.

Comparative Example 2 The same transparent resin plate as used in Example 1 [“Sx000
0 ", thickness 3 mm, size 200 mm × 300 mm, no hard coat layer on the surface].
Film [thickness 184Myuemu, moisture permeability 3g / m ^2/24 hours, 200 mm × 300 mm size] were laminated via an acrylic pressure sensitive adhesive, to obtain a laminate. Table 1 shows the evaluation results of the laminate. If this laminate is used as a front panel for a plasma display for a long period of time when placed on the front of the plasma display, bubbles may be generated between the PET film and the transparent resin substrate.

[0030]

[Table 1] 機能 Film function (type) Moisture permeability High temperature drying durability in durability at high temperature and high humidity (g / m ^2/24 hours) ───────────────────────────── ────── Example 1 Anti-reflection (TAC) 234 ○ ○ Anti-reflection (TAC) 234 ○ ○ Example 2 Anti-reflection (TAC) 234 ○ ○ Anti-glare (TAC) 227 ○ ○ Example 3-(PET ) 24 ○ ○ Example 4 Heart @ coat (PMMA) 24 ○ ○ Example 5 Heart @ coat (PC) 29 ○ ○ Comparative example 1 Electromagnetic wave / infrared shielding (PET) 0 × × Anti-reflection (TAC) 234 ○ ○ Comparative example 2 − (PET) 3 × × ───────────────────────────────────

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukio Yasuo 2-10-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Kagaku Kogyo Co., Ltd. F-term (reference) 5C040 GH10 JA09 KA14 KB24 KB29 MA10 5C094 AA11 AA31 AA60 BA31 DA12 EB02 ED01 ED12 GB10 5G435 AA00 AA01 AA12 AA14 AA16 BB06 GG33 HH02 HH03 HH05 KK07

Claims (2)

[Claims] 1. A display front plate comprising a laminate in which a plastic film is laminated on at least one surface of a transparent resin substrate via a pressure-sensitive adhesive layer, wherein the plastic film has a moisture permeability of 10 g / m. ^A front panel for a display, which is not less than 2/24 hours. 2. The display front panel according to claim 1, which is used for a plasma display device.