JPH117251A - Front surface plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent front surface plate for a plasma display which substantially prevents the easy peeling of a laminated film from a transparent substrate formed with a hard-coating layer by laminating the film on the hard- coating layer of this transparent substrate. SOLUTION: The transparent substrate of this front surface plate consists of a synthetic resin, etc., such as, acrylic resin, polycarbonate, polystyrene and methyl methacryate-styrene copolymer. The hard-coating layer is previously formed on the surface of the transparent substrate on the side to be laminated with the film and the film is laminated thereon. The hard-coating layer is merely necessitated to be formed on at least one surface of the transparent substrate in the case the film is laminated on the one surface thereof. The hard-coating layer is similar to ordinary used hard-coating layers and includes, for example, a layer formed by polymerizing and curing a multifunctional monomer or its oligomer. While the thickness of the hard coat layer is not particularly limited, the thickness is preferably about 1 to 20 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates to a front plate.

[0003]

2. Description of the Related Art In recent years, plasma displays have attracted attention as flat displays having a large display area. However, a plasma display requires a front panel for shielding electromagnetic waves and near infrared rays generated from its screen and the like. Such a front plate is usually used after one or both surfaces thereof are subjected to an anti-reflection treatment in order to prevent the visibility from being lowered due to the reflection of the surrounding scenery. As such an anti-reflection treatment, for example, a treatment of forming an anti-reflection layer on the surface of the front plate by vapor deposition or the like is known (Japanese Patent Publication No. 7-89597), but the front plate is suitable for a large-sized plasma display. Cannot be easily processed, such as the necessity of a large-scale vacuum equipment to produce the product. Therefore, in order to easily perform an anti-reflection treatment, a method of performing an anti-reflection treatment by laminating a film on which an anti-reflection layer or the like is formed in advance on a transparent substrate has been proposed. In addition, a method of laminating a near-infrared film to shield near-infrared rays generated from a plasma display has been proposed. Further, a protective film for preventing the front plate surface from being damaged may be used in a laminated state.

[0004] However, since the plasma display is relatively hot, when the front plate on which such a film is laminated is used for the plasma display, there is a problem that the film is easily peeled off from the transparent substrate after a long-term use. .

[0005]

Accordingly, the present inventors have conducted intensive studies to develop a front plate in which a laminated film is not easily peeled off from a transparent substrate even when used for a long time under a high temperature. By providing a hard coat layer on a transparent substrate, it was found that the laminated film was not easily peeled off, and the present invention was reached.

[0006]

That is, the present invention provides a front plate comprising a transparent substrate having a hard coat layer formed thereon and a film laminated on the hard coat layer. is there.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The transparent substrate in the front plate of the present invention is made of, for example, a synthetic resin such as acrylic resin, polycarbonate, polystyrene, methyl methacrylate-styrene copolymer, and the like, and has a desired size. Acrylic resins are preferred because they can be easily processed and the effects of the present invention are remarkable. The thickness of the transparent substrate is usually 0.01 to 10 mm, preferably 0.5 to 10 mm.
mm, and includes not only plate-shaped ones but also film-shaped or sheet-shaped ones. The area is appropriately selected according to the target screen size of the display. Such a transparent substrate may be practically transparent, and may be colored with a dye, a pigment, or the like. Usually, wavelength 400
The light transmittance at -600 nm is 50% or more, preferably 60% or more.

[0008] Further, it may have a performance of shielding near infrared rays generated from the plasma display.
In this case, the average light transmittance at a wavelength of 850 to 1000 nm is preferably 10% or less. A transparent substrate having a performance of shielding near infrared rays is, for example, a monomer having an unsaturated double bond, a copolymer obtained by copolymerizing a phosphorus atom-containing monomer, and a resin containing a compound containing a copper atom. Composition (see, for example, JP-A-6-118228), resin composition containing a copper compound and a phosphorus compound (see, for example, Japanese Patent Publication No. 62-5190), resin composition containing a copper compound and a thiourea derivative (For example, see JP-A-6-73197) and a resin composition containing a tungsten-based compound (for example, USP-364772).
See No. 9. ) Can be easily manufactured.

On such a transparent substrate, a hard coat layer is previously formed on the surface on which the film is to be laminated. When a film is laminated on one surface of the transparent substrate, a hard coat layer may be formed on at least one surface, and when a film is laminated on both surfaces, a hard coat layer is formed on both surfaces of the transparent substrate. What is necessary is just to form a coat layer.

The hard coat layer is the same as that usually used, for example, a layer obtained by polymerizing and curing a polyfunctional monomer or an oligomer thereof. Here, examples of the polyfunctional monomer include an acrylic monomer, a silicon monomer, an epoxy monomer, and a melamine monomer. After a hard coat agent such as an acrylic hard coat agent, a silicon hard coat agent, an epoxy hard coat agent, and a melamine hard coat agent containing such a monomer or its oligomer as a main component is applied, it is polymerized and cured. A hard coat layer is formed.

Examples of the acrylic monomer include a polymerizable compound having at least two (meth) acryloyloxy groups in a molecule. Specific examples of such a polymerizable compound include an ester compound of a polyhydric alcohol and (meth) acrylic acid, a urethane-modified (meth) acryl obtained from a compound having an isocyanate group at a terminal and a (meth) acrylic acid derivative having a hydroxyl group. Oligomers and the like.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol,
Dihydric alcohols such as 2-ethyl-1,3-hexanediol, 2,2'-thiodiethanol, 1,4-cyclohexanedimethanol, trimethylolpropane, pentaglycerol, glycerol, pentaerythritol, diglycerol, dipenta Examples include trihydric or higher alcohols such as glycerol and dipentaerythritol.

Such an ester compound of a polyhydric alcohol and (meth) acrylic acid is used as a mixed ester by further adding a small amount of a polyunsaturated carboxylic acid in order to impart flexibility to the obtained cured film and to prevent cracking. Is also good. Examples of the polyunsaturated carboxylic acid include succinic acid, tetrahydrophthalic acid, phthalic acid, maleic acid, fumaric acid, and itaconic acid. The urethane-modified (meth) acrylic oligomer can be obtained, for example, by a method in which a terminal isocyanate polyurethane obtained by reacting a polyisocyanate with an oligomer having a plurality of hydroxyl groups is reacted with a (meth) acrylic acid derivative. Examples of the polyisocyanate include hexamethylene diisocyanate and isophorone isocyanate, examples of the oligomer having a plurality of hydroxyl groups include polycaprolactone diol and polytetramethylene diol, and examples of the (meth) acrylic acid derivative include (meth) acrylic acid-2- Examples include hydroxyalkyl (meth) acrylate compounds such as hydroxyethyl and 2-hydroxypropyl (meth) acrylate.

The polyfunctional monomer or its oligomer is
For example, after being mixed with an initiator, it is applied on a transparent substrate by a usual method such as spin coating, dip coating, roll coating, gravure coating, curtain flow coating, and then polymerized and cured. Further, it may be applied after being diluted with various solvents. In that case, the solvent is usually volatilized after application and before curing.

In the polymerization curing, ultraviolet curing, heat curing, and the like are performed depending on the polyfunctional monomer or its oligomer used.
Electron beam curing or the like is appropriately selected.

The thickness of the hard coat layer formed on the surface of the transparent substrate is not particularly limited, but is preferably about 1 to 20 μm. When the thickness is 1 μm or less, interference fringes due to the hard coat layer tend to occur, and when the thickness exceeds 20 μm, the hard coat layer tends to crack. In order to improve the adhesion between the transparent substrate and the hard coat layer, an adhesive layer may be provided between the transparent substrate and the hard coat layer.

In the front plate of the present invention, a film is laminated on the hard coat layer. The film is not particularly limited, and examples thereof include functional films such as an antireflection film, a protective film, and a near-infrared shielding film, and a laminated film in which a plurality of these functional films are laminated.

The antireflection film is a film in which an antireflection layer is formed on a film. Examples of the antireflection layer include a layer made of a low refractive index material such as magnesium fluoride and silicon oxide, and a low refractive material. And a multi-layer antireflection layer in which a layer made of a high refractive index material such as titanium oxide, tantalum oxide, tin oxide, indium oxide, zirconium oxide, and zinc oxide is combined. Among them, aluminum oxide, magnesium fluoride, and silicon oxide are preferable in terms of heat resistance.

A multilayer antireflection layer in which a layer made of indium oxide and tin oxide (ITO layer) and a layer made of silicon oxide are combined has a higher antireflection effect, and is excellent in surface hardness, adhesion, and economy. Is preferred. A multilayer antireflection layer composed of at least two layers of a layer made of silicon oxide and a layer made of titanium oxide is preferable because it has excellent transparency, surface hardness, adhesion, and economy. The antireflection layer may be a single layer in which a substance having a lower refractive index than the base film is applied with a thickness of, for example, about 0.05 to 0.3 μm.

Examples of the protective film include a hard coat film in which the surface of the film is subjected to a hard coat treatment.

Examples of the near-infrared shielding film include a resin composition containing a monomer having an unsaturated double bond, a copolymer obtained by copolymerizing a phosphorus atom-containing monomer, and a compound containing a copper atom. Film consisting of
No. 8228), a film composed of a resin composition containing a copper compound and a phosphorus compound (Japanese Patent Publication No. 62-5190), and a film composed of a resin composition containing a copper compound and a thiourea derivative (JP-A-6-73197). And a film made of a resin composition containing a tungsten-based compound (US Pat. No. 3,647,729). The material of the film is not particularly limited as long as it has transparency, but ease of handling, workability,
In terms of economy, usually an ester resin film mainly composed of an ester resin such as polyethylene terephthalate, an acrylic resin film mainly composed of an acrylic resin such as polymethyl methacrylate, a cellulose resin such as triacetyl cellulose Cellulose resin film containing resin as a main component, polyolefin film containing olefin resin such as polypropylene and polymethylpentene as a main component, polycarbonate film containing polycarbonate as a main component, and polyvinyl chloride containing polyvinyl chloride as a main component. A vinyl resin film or the like is used.
The surface of such a film may be subjected to a hard coat treatment, and its thickness is usually about 20 to 500 μm.

When such a film is used as the outermost layer of the front panel, an antifouling layer may be further formed on the surface thereof. Such an antifouling layer can be easily formed by, for example, applying a solution of a fluorine-based coupling agent or a silicon-based coupling agent, followed by drying.

In order to laminate such a film and a transparent substrate, for example, the film may be laminated using an adhesive. Examples of the adhesive include an acrylic adhesive and a rubber adhesive. The lamination may be performed, for example, by applying an adhesive to one surface of the film, and then pressing the film and the transparent substrate by using a roll bonding machine, a single-wafer bonding machine, or the like. When a layer such as an antireflection layer is formed on the film, the pressure-sensitive adhesive is usually applied to the film surface opposite to the surface on which the layer is formed. Alternatively, the film may be laminated after applying the adhesive to the transparent substrate.

Thus, the front plate of the present invention can be obtained. On the film laminated on the front plate, other films such as an antireflection film, a conductive film, and a near-infrared shielding film may be further provided depending on the use. A film, a protective film, and the like may be laminated.

[0025]

The front plate of the present invention is excellent as a front plate for a plasma display because the laminated film is not easily peeled off from the transparent substrate even when used for a long time at a high temperature.

[0026]

EXAMPLES 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 obtained front plate was evaluated by the following method.

High-Temperature Durability Test The front plate was placed in an oven at 80 ° C., taken out after 1000 hours, and the appearance change of the front plate was visually compared with that before the test.

Reference Example 1 (Production of a transparent substrate) A hard coat agent [acrylic] diluted with a mixed solvent of xylene, ethyl acetate and ethylene glycol monobutyl ether (mixing ratio 3: 1: 1) so that the solid content becomes 40%. Acrylic resin plate [size 600 × 400 mm, thickness 4 m]
m, manufactured by Sumitomo Chemical Co., Ltd., Sumipex E] was dipped, pulled up at a speed of 30 cm / min, and a hard coat agent was applied to the surface of the acrylic resin plate. After evaporating the solvent, a 120 W metal halide lamp (UB0451:
(Eye Graphic Co., Ltd.) for 10 seconds from a distance of 20 cm to form a hard coat layer (5 μm in thickness) on the transparent substrate.

Reference Example 2 (Production of antireflection film) Polyethylene terephthalate (hereinafter referred to as PET)
An aluminum oxide-magnesium fluoride layer and a silicon dioxide layer were sequentially laminated on a film [188 μm in thickness, ester film, manufactured by Toyobo Co., Ltd., trade name] to form an anti-reflection layer to obtain an anti-reflection film. Formula _{(1) C 3 F 7 -} (OCF 2 CF 2 CF 2) 24 -O (CF 2) 2 - [ _{[CH 2 CH-Si- (OCH 3} ) 3 ] _p] -H (1) (in the formula , P represents an integer of 1 to 10), which is diluted with tetradecafluorohexane with a number average molecular weight of about 5,000 and an average value of p of 2.0.
With the concentration of the fluorine-containing silane compound being 0.1% by weight, a solution of a fluorine-based coupling agent was obtained. After laminating a mask film on the surface of the antireflection film obtained above opposite to the surface on which the antireflection layer is formed, the film is immersed in the solution obtained above and at a speed of 15 cm / min. It was pulled up and applied. After application, the solvent was volatilized by standing at room temperature for 24 hours to form an antifouling layer on the antireflection layer.

Example 1 The antireflection film obtained in Reference Example 2 was laminated on one surface of the transparent substrate obtained in Reference Example 1. Lamination of anti-reflection film,
Adhesive [Non-carrier 3132 manufactured by Lintec Co., Ltd.]
And by roll pressure bonding. Table 1 shows the results of the high-temperature durability test.

Example 2 One side of the transparent substrate obtained in Reference Example 1 was hard-coated with a PET film [thickness 50 μm, manufactured by Toyobo Co., Ltd.
Trade name ester film). The lamination of the film is performed using an adhesive [Nincarrier 313, manufactured by Lintec Co., Ltd.]
2] by roll pressure bonding. Table 1 shows the results of the high-temperature durability test.

Comparative Example 1 Acrylic resin plate [size 600 × 400 mm, thickness 4 m
m, manufactured by Sumitomo Chemical Co., Ltd., Sumipex E] was laminated on the antireflection film obtained in Reference Example 2. Lamination of the anti-reflection film is performed using an adhesive [Lintec Co.,
Non-carrier 3132] and roll pressing. Table 1 shows the results of the high-temperature durability test.

Comparative Example 2 Acrylic resin plate [size 600 × 400 mm, thickness 4 m
m, Sumipex E, manufactured by Sumitomo Chemical Co., Ltd.] on one side, a hard-coated PET film [thickness 50 μm
m, manufactured by Toyobo Co., Ltd., trade name: ester film]. The lamination of the film is performed using an adhesive [Lintech Co., Ltd.
And non-carrier 3132]. Table 1 shows the results of the high-temperature durability test.

[0034]

[Table 1] Example 1 Appearance change Example 1 No change Example 2 No change Comparative example 1 Air bubbles were generated, and peeling of the film was observed. Comparative Example 2 Air bubbles were generated, and peeling of the film was observed.

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Claims (6)

[Claims] 1. A front plate comprising a transparent substrate on which a hard coat layer is formed and a film laminated on the hard coat layer. 2. The front plate according to claim 1, wherein the film is an ester resin film, an acrylic resin film, a cellulose resin film, a polyolefin film, a polycarbonate film or a polyvinyl chloride resin film. 3. The front plate according to claim 1, wherein the film is an antireflection film, a protective film, or a near-infrared shielding film. 4. The hard coat layer is a layer obtained by polymerizing and curing a polyfunctional monomer or an oligomer thereof.
The front plate described in 1. 5. The front plate according to claim 1, wherein the thickness of the hard coat layer is 1 to 20 μm. 6. The front plate according to claim 1, wherein the transparent substrate is made of an acrylic resin, polycarbonate, polystyrene, or methyl methacrylate-styrene copolymer resin.