JP2003055607A - Transparent base material and its coat material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coat material having an inconspicuous interference fringe and a transparent base material providing the coat material. SOLUTION: In a stratified coat material formed on a transparent base material itself, the coat material for the transparent base material has not less than 0.001 to at least one wavelength in a wavelength range of 500-760 nm of an attenuation coefficient of the coat material and the transparent base material is formed on the surface of the transparent base material itself using the coat material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating material for a transparent substrate and a transparent substrate having a coating layer made of this coating material. The present invention is a CRT (cathode ray tube), PDP
It is applied to display devices such as (plasma display panel), transparent plates such as glass for automobiles and buildings, and various other fields.

[0002]

2. Description of the Related Art A hard coat layer is provided on the surface of a flat-type display such as a CRT or PDP, and interference fringes may appear due to the uneven thickness of the hard coat layer.

The interference fringes are generated by the interference of the reflected light from the transparent substrate body and the reflected light on the surface of the hard coat layer. That is, the light of the wavelength at which the reflected light from the base material main body and the hard coat layer on the surface of the hard coat layer are in phase,
Light having a wavelength that is visually recognized as reflected light and has a phase opposite to that of the reflected light from the base material body and the reflected light from the hard coat layer cancels each other out.

The phase shift between the light reflected from the main body of the substrate and the light reflected from the surface of the hard coat layer depends on the film thickness of the hard coat layer and the wavelength of the light. Then, which wavelength of the reflected light appears as interference light and which wavelength of the reflected light is extinguished depends on the film thickness of the hard coat layer. The region where the film thickness of the hard coat layer is uneven is a region where the film thickness changes along the surface direction of the hard coat layer. Therefore, in this region, the interference light visually recognized along the surface direction of the hard coat layer. The wavelength of changes. According to this principle, if the hard coat layer has uneven thickness, interference fringes will appear.

If the film thickness of the hard coat layer is completely uniform, the interference light of the reflected light is monochromatic and the interference fringes are not visible, but it is impossible to form a hard coat layer having a completely uniform film thickness. I really can't.

Further, if the thickness of the hard coat layer is made extremely large, light having a large number of wavelengths appears as interference light at the same reflection point, and the interference light becomes multicolored, so that interference fringes are hardly noticeable. Becomes However, when the film thickness of the hard coat layer is increased, the film formation cost is increased and the hard coat layer is easily cracked, which is not practical.

In addition, as a remark, the width of the interference fringes of the reflected light depends on the wavelength of the light, and the longer the wavelength of the light, the larger the width of the interference fringes of the reflected light, so that it is easily visually recognized.

As another measure for preventing interference fringes, there is a method of bringing the refractive index of the layer under the hard coat layer close to the refractive index of the hard coat layer, but the refractive index of the hard coat layer is usually 1.46 to 1. A substrate having a refractive index close to 0.55 (for example, triacetyl cellulose) is generally quite expensive and not practical.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above conventional problems and provide a transparent base material in which interference fringes are inconspicuous and a coating material therefor at a relatively low cost.

[0010]

The coating material for a transparent base material of the present invention is a coating material formed in layers on a transparent base material body, and the attenuation coefficient of the coating material is at least in the wavelength range of 500 to 760 nm. 0.0 for one wavelength
It is characterized by being 01 or more.

Further, the transparent base material of the present invention comprises the transparent base material main body and the coating material provided in layers.

In such a transparent substrate with a coating material of the present invention, the reflected light reflected on the surface of the transparent substrate body is absorbed and attenuated by the coating material, so that it interferes with the reflected light on the surface of the coating material. The amount of light of the interference fringes generated becomes small and becomes inconspicuous.

It should be noted that the fact that the attenuation coefficient is 0.001 or more at least at one wavelength means that it is 500 to 7
The attenuation coefficient is 0.60 at some or all wavelengths of 60 nm.
It means that it is 001 or more. Therefore, 500-7
The attenuation coefficient may be less than 0.001 in some wavelength regions of 60 nm. However, in order to sufficiently suppress the interference fringes, the attenuation coefficient is preferably 0.001 or more at all wavelengths in the range of 500 to 760 nm.

The above-mentioned attenuation coefficient is 0.00 for at least one wavelength in the wavelength range of 500 to 760 nm.
It is preferably 25 or more, and particularly 600 to 700 n.
It is preferably 0.0025 or more for at least one wavelength in the wavelength range of m. Above all, 6
The attenuation coefficient is preferably 0.0025 or more in the entire wavelength range of 00 to 700 nm.

In order to obtain this attenuation coefficient, it is preferable that the coating material contains fine particles and / or dyes.

This coating material has a film thickness of 2 μm or more, for example, 2
˜50 μm is preferred.

The coating material of the present invention is preferably a hard coating material.

This coating material may be formed as a coating layer on a transparent substrate by itself as a coating material, and it is formed as a coating layer on the transparent film, and the transparent film with the coating material layer is attached to the transparent substrate. May be.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments will be described below.

The coating material of the present invention is preferably structured so as to have the above-mentioned attenuation coefficient by incorporating fine particles and / or dyes in a transparent matrix phase. A synthetic resin is preferable as the matrix phase.
As the synthetic resin, a thermosetting resin or an ionizing radiation curable resin is suitable, but it is preferable to use an ionizing radiation curable resin from the viewpoints of work environment and productivity. The ionizing radiation curable resin is formed from a coating material containing at least a resin that is cured by electron beam or ultraviolet irradiation. Specifically, it contains a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator, and further contains a sensitizer, a non-reactive resin, an additive such as a leveling agent, and a solvent, if necessary. Is. The structure and molecular weight of the photopolymerizable prepolymer are related to the curing of the ionizing radiation curable coating material, and the properties such as hardness and crack resistance are determined. The photopolymerizable polymer is generally of the type that undergoes radical polymerization when the acryloyl group introduced into the skeleton is irradiated with ionizing radiation. Those that are cured by radical polymerization have a high curing speed and a large degree of freedom in resin design, and are particularly preferable. As the photopolymerizable prepolymer, an acrylic prepolymer having an acryloyl group is particularly preferable, and one having two or more acryloyl groups in one molecule and having a three-dimensional network structure. As the acrylic prepolymer, urethane acrylate, melamine acrylate, polyester acrylate and the like can be used. The photopolymerizable monomer is used for diluting the high-viscosity photopolymerizable prepolymer to lower the viscosity and improve workability, and as a cross-linking agent to impart coating film strength.

The fine particles for increasing the damping coefficient include
Au, Ag, Co, Cu, Cr, Al, Ti, W, M
n, Pt, Nb, In, Zn, Sn, Ni, Pb, Pd
Etc., metal oxides such as SiO _x , ITO, ATO, ZnO, metal nitrides such as TiN, TiN _x O _y , CN _x , BN _x , SiC, SiC _x O _y , SiC _x N _z , Si.
Other C _x O _y N _z or the like of a metal carbide, graphite, amorphous carbon such as carbon fiber, or of two or more of these composite materials, it is possible to use various dyes. Examples of the dye include azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, and quinophthalone pigments.

The particle size of the fine particles is 300 nm or less, especially 0.5.
It is preferably about 100 nm.

The amount of the fine particles to be blended is selected so that the damping coefficient falls within the above range, for example, in the range of 0.1 to 50% by volume, particularly 0.2 to 5% by volume.

The compounding amount of the dye also differs depending on the kind of the dye, and is selected so that the attenuation coefficient falls within the above range.

The coating material of the present invention may be formed into a film by itself, or may be a coating layer and a film formed on a transparent film, and a transparent material other than the transparent film may be used. It may be formed as a coat layer on a base material (for example, a glass plate or a transparent synthetic resin plate). The transparent base material such as glass plate and synthetic resin plate is CR
It may be used for displays such as T and PDP, as well as for automobiles and constructions.

When a coat layer is formed on a transparent film or other transparent substrate, an underlayer may be provided to enhance the adhesion strength of the coat layer, or another layer may be further provided.

The coating material of the present invention is particularly preferably used as a hard coat layer. The hardness of the hard coat layer is preferably H or higher in terms of pencil hardness. The film thickness of the hard coat layer is preferably 2 μm or more, particularly 5 μm or more, for example, about 5 to 50 μm in order to obtain a sufficient attenuation effect of reflected light. When the thickness is more than 25 μm, interference fringes with a wavelength of 500 nm or less are hardly visible.

To form this hard coat layer, a film forming process such as a bar coat method, a blade coat method, a spin coat method or the like may be adopted.

[0029]

Example 1 0.2 volume of silver (Ag) fine particles having an average particle diameter of 30 nm as metal fine particles was used for 99.8 parts by volume of a hard coating liquid (stock solution) (Z7501 manufactured by Japan Synthetic Rubber Co., Ltd.). Parts by weight, and further diluted with 100 parts by volume of methyl ethyl ketone to obtain a coating liquid. Use a bar coater to make this 1
It was applied to a 88 μm PET film so that the film thickness after drying would be 5 μm. Then, the ultraviolet rays are 500 mJ / cm
^{It was} irradiated with ² rays and cured to form a hard coat layer.

The attenuation coefficient of this hard coat layer for each wavelength is shown in FIG.

Further, the amplitude value of the waveform of the interference wave with respect to the light having the wavelength of 550 nm of the PET film with the hard coat layer was measured.

Example 2 In Example 1, the ratio of the stock solution for hard coat was 9%.
A hard coat layer was formed in the same manner except that the content was 9.4 parts by volume and the ratio of the metal fine particles was 0.6 parts by volume, and the same measurement was performed.

Comparative Example 1 In Example 1, the ratio of the stock solution for hard coat was 1
A hard coat layer was formed in the same manner except that the metal fine particles were not added, and the same measurement was performed.

As shown in FIG. 1, the attenuation coefficients of the hard coat layers of Examples 1 and 2 are higher than 0.0025 in the entire wavelength range of 350 to 800 nm.

Further, Examples 1 and 2 in which the amplitude value of the waveform of the interference wave of 550 nm of Comparative Example 1 was set to 100% relative value
The amplitude values of Example 1 were 62% and Example 2 was 18%, and it was confirmed that the interference wave was weak.

[0036]

As described above, according to the present invention, a coating material in which interference fringes are not noticeable and a transparent substrate provided with the coating material are provided.

[Brief description of drawings]

FIG. 1 is a graph showing the results of Examples.

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Claims (8)

[Claims] 1. A coating material formed in layers on a transparent substrate body, wherein the coating material has an attenuation coefficient of 0.001 or more for at least one wavelength in a wavelength range of 500 to 760 nm. A coating material for transparent base materials. 2. The attenuation coefficient according to claim 1, wherein the attenuation coefficient is 0.0 for at least one wavelength in the wavelength range.
A coating material for a transparent substrate, which is 025 or more. 3. The damping coefficient according to claim 2, wherein the damping coefficient is 60.
A coating material for a transparent substrate, which is 0.025 or more for at least one wavelength within a wavelength range of 0 to 700 nm. 4. The coating material for a transparent substrate according to claim 1, wherein the coating material has a film thickness of 2 μm or more. 5. A coating material for a transparent substrate according to claim 1, wherein the attenuation coefficient is obtained by containing fine particles and / or dyes. 6. The coating material for a transparent substrate according to claim 1, which is a hard coating material. 7. The coating material for a transparent substrate according to claim 1, which is in the form of a film. 8. A transparent substrate having a coat layer on a transparent substrate body, wherein the coat layer comprises the coating material according to any one of claims 1 to 7.