JP2000313871A - Pressure sensitive adhesive composition for attaching functional film and image display device - Google Patents

Abstract

(57) [Summary] [Problem] A pressure-sensitive adhesive composition for attaching a functional film and a feeling of attaching a functional film, which can realize excellent contrast and suppression of optical halation easily and inexpensively even on a flat screen. Obtain a pressure-sensitive adhesive sheet. SOLUTION: The pressure-sensitive adhesive composition for sticking a functional film is a pressure-sensitive adhesive composition for sticking and fixing a functional film on the surface of an image display portion of an image display device. And a black pigment having an average particle size of 0.5 μm or less. The pressure-sensitive adhesive sheet for attaching a functional film is a pressure-sensitive adhesive sheet for attaching and fixing a functional film to the surface of an image display unit of an image display device, and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive sheet The layer is composed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive and a black pigment having an average particle size of 0.5 μm or less, and the pressure-sensitive adhesive layer has a visible light transmittance of 10 to 90%. And the haze value is 15% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet for adhering and fixing a functional film to the surface of an image display section of an image display device, and to a pressure-sensitive adhesive for an image display surface. The present invention relates to an image display device to which a functional film is stuck and fixed via a layer of an agent.

[0002]

2. Description of the Related Art Conventionally, in an image display device for displaying an image on a cathode ray tube (CRT), enhancement of contrast of a displayed image and suppression of optical halation in which a light beam emitted inside the display is generated between the panel and the panel. For the purpose,
A method has been adopted in which a panel portion of a cathode ray tube is mixed with a dye and dyed to absorb the total reflected light.

[0003] In recent years, flattening of the image display surface has been rapidly promoted due to the consumer's intention such as less distortion of the image and beautiful appearance. However, when the image display surface is flattened, there is a problem that the explosion-proof performance of the CRT is reduced. As one of the measures,
A technique has been adopted in which the thickness of the peripheral portion of the panel of the cathode ray tube is made larger than the thickness of the central portion. At that time, if the panel is dyed by a normal method, the transmittance is different between the central part and the peripheral part of the panel, so it is necessary to change the degree of staining of the panel between the central part and the peripheral part. However, in this method, it is necessary to arrange various types of panels with different degrees of staining for each part of the panel,
It has the disadvantage of being very costly. Note that a functional film such as an antireflection film, a conductive film, or an antiglare film is often attached to the image display surface of the image display device.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive composition for attaching a functional film which can realize excellent contrast and suppression of optical halation easily and inexpensively even on a flat screen. An object of the present invention is to provide a pressure-sensitive adhesive sheet for attaching an object and a functional film. Another object of the present invention is to provide a flat screen,
An object of the present invention is to provide an image display device which is excellent in contrast, has little optical halation, and can be obtained easily and at low cost.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have focused on a pressure-sensitive adhesive composition used for attaching a functional film to an image display surface. The present inventors have found that when the composition is colored with a specific pigment, excellent contrast and suppression of optical halation can be easily and inexpensively realized even on a flat image display surface, and the present invention has been completed.

That is, the present invention relates to a pressure-sensitive adhesive composition for sticking and fixing a functional film on the surface of an image display portion of an image display device.
Provided is a pressure-sensitive adhesive composition for attaching a functional film, comprising a black pigment of 5 μm or less. The present invention is also a pressure-sensitive adhesive sheet for attaching and fixing a functional film to an image display unit surface of an image display device,
The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet is composed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive and a black pigment having an average particle size of 0.5 μm or less, and the pressure-sensitive adhesive Provided is a pressure-sensitive adhesive sheet for attaching a functional film, wherein the layer has a visible light transmittance of 10 to 90% and a haze value of 15% or less. The present invention further provides a pressure-sensitive adhesive and an average particle size of 0.5
The functional film is formed of a pressure-sensitive adhesive composition containing a black pigment of not more than μm and a pressure-sensitive adhesive layer having a visible light transmittance of 10 to 90% and a haze value of 15% or less. Provided is an image display device that is stuck and fixed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The black pigment used in the present invention is not particularly limited, and ordinary black pigments can be used. However, pigments which hardly settle when blended in a pressure-sensitive adhesive composition, for example, having a specific gravity of 1 Pigments of about 0.0 to 3.0 are preferred. Examples of such a black pigment include carbon black, graphite, and iron black.

The average particle size of the black pigment is 0.5 μm or less, for example, about 0.01 to 0.5 μm, preferably 0.1 to 0.5 μm.
It is about 0.5 to 0.45 μm. Average particle size 0.5μm
Exceeding is undesirable because speckles become visible on the surface of the image display unit. The content of the black pigment in the pressure-sensitive adhesive composition can be appropriately selected within a range that does not impair the visible light transmittance, and for example, 0.1 to
It is about 10% by weight, preferably about 0.5 to 6% by weight.

As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive composition, a conventional pressure-sensitive adhesive such as an acrylic, rubber, or silicone can be used. Acrylic pressure-sensitive adhesives are preferred.

The acrylic polymer used as the base polymer of the acrylic pressure-sensitive adhesive includes homopolymers and copolymers of alkyl (meth) acrylate. The monomers constituting the copolymer include:
In addition to (meth) acrylic acid alkyl esters, (meth)
Other monomers copolymerizable with the alkyl acrylate are also included.

Specific examples of the alkyl (meth) acrylate include, for example, methyl (meth) acrylate,
Ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate And _C1-16 alkyl (meth) acrylates such as nonyl (meth) acrylate and lauryl (meth) acrylate. These alkyl (meth) acrylates can be used alone or in combination of two or more.

Other monomers copolymerizable with the alkyl (meth) acrylate include, for example, vinyl esters such as vinyl acetate; styrene, vinyl toluene, α
-Aromatic vinyl compounds such as methylstyrene; (meth)
Cyano group-containing monomers such as acrylonitrile; (meth)
Amide group-containing monomers such as acrylamide; carboxyl group or acid anhydride group-containing monomers such as (meth) acrylic acid, succinic acid, and maleic anhydride; 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl ( Hydroxyl-containing monomers such as meth) acrylate, 4-hydroxybutyl (meth) acrylate and 6-hydroxyhexyl (meth) acrylate; glycidyl-containing monomers such as glycidyl (meth) acrylate;
Any of various monomers known as monomers for modifying acrylic pressure-sensitive adhesives, such as amino group-containing monomers such as N-dimethylaminoethyl (meth) acrylate, can be used. These other copolymerizable monomers are usually
50% by weight based on all constituent monomers of acrylic polymer
It is used in the following ratio (for example, about 0 to 50% by weight, preferably about 2 to 30% by weight).

The acrylic pressure-sensitive adhesive may contain a crosslinking agent. As the crosslinking agent, known or commonly used crosslinking agents can be used, and it is particularly preferable to use a polyfunctional melamine compound and / or a polyfunctional epoxy compound. Specifically, as the polyfunctional melamine compound, for example, methylated methylol melamine, butylated hexamethylol melamine, and the like, and as the polyfunctional epoxy compound,
For example, diglycidyl aniline, glycerin diglycidyl ether and the like can be mentioned. The amount of these crosslinking agents used is
Usually 0.0 to 100 parts by weight of the acrylic polymer
It is in the range of about 0.01 to 10 parts by weight, preferably about 0.01 to 5 parts by weight.

Further, a polyfunctional isocyanate compound may be blended with the acrylic pressure-sensitive adhesive. As such a polyfunctional isocyanate compound, for example, tolylene diisocyanate, hexamethylene diisocyanate,
Examples include polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate, trimethylolpropane tolylene diisocyanate, polyether polyisocyanate, polyester polyisocyanate, and the like.
The amount of these polyfunctional isocyanate compounds to be used is, for example, 0.01 to 20 parts by weight, preferably about 0.05 to 15 parts by weight, based on 100 parts by weight of the acrylic polymer. .

The pressure-sensitive adhesive composition contains a conventional silane coupling agent in order to improve the adhesion to the glass constituting the surface of the image display portion, or a rosin-based resin in order to improve the adhesion. A conventional tackifier (tack fire) such as a terpene resin or a petroleum resin or other conventional additives may be blended. The pressure-sensitive adhesive composition for attaching a functional film according to the present invention is, for example, a base polymer constituting an adhesive, an additive such as a crosslinking agent, if necessary, and the black pigment mixed in a solvent. , By uniformly dispersing the black pigment.

FIG. 1 is a schematic sectional view showing an example of a pressure-sensitive adhesive sheet for attaching a functional film of the present invention, and FIG. 2 is a partial schematic sectional view showing an example of an image display device of the present invention. The pressure-sensitive adhesive sheet 1 in FIG. 1 is a substrate-less adhesive sheet in which a pressure-sensitive adhesive layer 3 is provided on a release liner 2. Further, in the image display device 4 of FIG. 2, the functional film 5 is adhered and fixed via the pressure-sensitive adhesive layer 3 to the surface of the image display portion of a cathode ray tube (glass bulb) 6 having a flat image display surface. .

The visible light transmittance of the pressure-sensitive adhesive layer 3 is 10
To 90%, preferably about 30 to 80%. Also,
The haze value of the pressure-sensitive adhesive layer 3 is 15% or less, preferably 10% or less. If the visible light transmittance is less than 10% or the haze value exceeds 15%, a clear image cannot be obtained. On the other hand, when the visible light transmittance exceeds 90%, the contrast is reduced and the optical halation becomes remarkable. The thickness of the pressure-sensitive adhesive layer 3 is, for example, 5
About 100 μm, preferably about 10 to 50 μm. The visible light transmittance and the haze value can be adjusted by appropriately selecting the amount of the black pigment contained in the pressure-sensitive adhesive layer 3 and the thickness of the pressure-sensitive adhesive layer 3.

The above-mentioned substrate-less adhesive sheet is prepared, for example, by applying the above-mentioned pressure-sensitive adhesive composition of the present invention on a release liner made of a polyethylene terephthalate film having a release layer, drying the composition, And heat-crosslinking.

The pressure-sensitive adhesive layer 3 may be composed of a plurality of layers with or without another layer. For example, the pressure-sensitive adhesive sheet for attaching a functional film of the present invention may be a double-sided adhesive sheet in which a pressure-sensitive adhesive layer 3 is provided on both sides of a transparent substrate. Examples of the transparent substrate include a plastic film such as a polyethylene terephthalate film. The thickness of the transparent substrate is, for example, about 5 to 100 μm, preferably 10 to 100 μm.
It is about 50 μm. Such a double-sided adhesive sheet can be obtained, for example, by applying the above-mentioned pressure-sensitive adhesive composition of the present invention to both sides of a transparent substrate, drying and, if necessary, heat-crosslinking.

The functional film 5 is not particularly limited as long as it is a film (including a sheet) capable of imparting some function to the surface of the image display unit, and examples thereof include an antireflection film, a conductive film, and an antiglare film. Can be The material of the functional film 5 can be appropriately selected depending on the application, but is usually polyethylene terephthalate (PE).
T), polycarbonate, triacetyl cellulose (T
AC), polyurethane and the like. The thickness of the functional film 5 is, for example, 10 to 2000 μm depending on the use.
It can be appropriately selected from a range of about m.

The image display device of the present invention has a CRT 6
(CRT) as well as image display devices requiring similar excellent contrast, for example, PDP
(Plasma display panel) and the like. The image display device 4, for example, laminates the functional film 5 on the adhesive surface of the pressure-sensitive adhesive sheet 1, peels off the release liner 2 from the laminate,
Can be obtained by pasting on the surface of the image display section. When the double-sided adhesive sheet is used as the pressure-sensitive adhesive sheet, the functional film 5 is laminated on one adhesive side of the double-sided adhesive sheet, and the other adhesive side is used to make use of the surface of the image display section of the cathode ray tube 6. The image display device 4 can be obtained.

In such an image display device, since a pressure-sensitive adhesive layer having specific optical characteristics is provided on the surface of the image display portion, optical halation is remarkably suppressed, and a high quality image with enhanced contrast is provided. Image quality is obtained.
Further, the transmittance can be easily controlled to a desired value only by changing the compounding amount of the black pigment. Furthermore, since the pressure-sensitive adhesive composition of the present invention can be obtained only by dispersing a black pigment in a pressure-sensitive adhesive used when attaching a functional film, both simplicity and low cost can be achieved.

[0023]

According to the pressure-sensitive adhesive composition for attaching a functional film and the pressure-sensitive adhesive sheet for attaching a functional film of the present invention, excellent contrast and suppression of optical halation can be obtained even on a flat screen. It can be realized simply and inexpensively. ADVANTAGE OF THE INVENTION According to the image display apparatus of this invention, even if it is a flat screen, high-quality image with high contrast and little optical halation can be achieved simply and inexpensively.

[0024]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” means “parts by weight”.

Example 1 95 parts of isooctyl acrylate, 5 parts of acrylic acid, and 0.5 part of 3-hydroxypropyl acrylate were polymerized in toluene to form an acrylic polymer ( _Mw = 950,000, _Mw
/ To obtain a M _n = 3.5 in toluene). 0.05 parts of glycerin diglycidyl ether was added to this polymer solution, and 2 parts of a black pigment (average particle size: 0.3 μm) composed of carbon black was further added to obtain a pressure-sensitive adhesive composition. The composition was cast and coated on a release liner made of a 38 μm-thick polyethylene terephthalate film so as to have a thickness of about 25 μm after drying.
For 3 minutes, followed by aging at 50 ° C. for 72 hours to produce a pressure-sensitive adhesive sheet having a cross-linked structured pressure-sensitive adhesive layer. The visible light transmittance of the pressure-sensitive adhesive layer was measured by a spectrophotometer at 550 nm.
%Met. The haze value of the pressure-sensitive adhesive layer measured by a film turbidimeter was 2.0%. An optical film (thickness 20) is formed on the adhesive surface of the pressure-sensitive adhesive sheet.
0 μm) was laminated, the release liner was peeled off, and the laminate was adhered to the surface of the image display section of a cathode ray tube made of a uniform dye to obtain an image display device.

Comparative Example 1 A black pigment having an average particle size of 0.3 μm was replaced with an average particle size of 0.3 μm.
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet were produced in the same manner as in Example 1, except that 2 parts of a 7 μm black pigment was blended. When the visible light transmittance and the haze value of the pressure-sensitive adhesive layer of the obtained pressure-sensitive adhesive sheet were measured by the same methods as in Example 1, they were 60% and 3.0%, respectively. An optical film (thickness: 200 μm) was laminated on the adhesive surface of the pressure-sensitive adhesive sheet, and after peeling off the release liner, it was adhered to the surface of the image display section of a cathode ray tube made of a uniform dye to obtain an image display device. .

Comparative Example 2 An image display apparatus in which a cathode-ray tube was made of glass in which the amount of the dye was changed according to the thickness was designated as Comparative Example 2.

Evaluation (Appearance) The surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was 20
The sample was observed at a magnification of 00 times, and it was determined as x if there was at least one spot (concavo-convex) of 0.5 μm or more on a 5 cm square, and it was judged as o if not. (Cost) An image display device requiring a large cost for manufacturing was evaluated as x, and an image display device capable of being manufactured at low cost was evaluated as ○.

Table 1 shows the above results. As is clear from Table 1, the image display device obtained in Example 1 can obtain a high-quality display image and does not cost much.

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a pressure-sensitive adhesive sheet for attaching a functional film of the present invention.

FIG. 2 is a partial schematic sectional view showing an example of the image display device of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure-sensitive adhesive sheet 2 release liner 3 pressure-sensitive adhesive layer 4 image display device 5 functional film 6 CRT

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H042 AA06 AA11 AA26 4J040 CA001 DF041 DF051 EK031 JA09 JB09 KA03 KA16 KA35 LA07 LA10 NA21 PA17

Claims (3)

[Claims] 1. A pressure-sensitive adhesive composition for attaching and fixing a functional film to the surface of an image display section of an image display device, comprising: a pressure-sensitive adhesive; a black pigment having an average particle size of 0.5 μm or less; A pressure-sensitive adhesive composition for attaching a functional film, comprising: 2. A pressure-sensitive adhesive sheet for attaching and fixing a functional film to the surface of an image display section of an image display device, wherein the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer. And a black pigment having an average particle size of 0.5 μm or less, the pressure-sensitive adhesive layer has a visible light transmittance of 10 to 90%, and a haze value of 15%. % Or less, a pressure-sensitive adhesive sheet for attaching a functional film. 3. A pressure-sensitive adhesive composition comprising a pressure-sensitive adhesive and a black pigment having an average particle size of 0.5 μm or less on the surface of an image display portion, and has a visible light transmittance of 10 to 90%.
Through a pressure-sensitive adhesive layer having a haze value of 15% or less,
An image display device on which a functional film is adhered and fixed.