Coating material for forming antistatic high-refractive-index film, transparent material laminate provided with antistatic antireflective film, and cathode-ray tube

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a coating material for forming an antistatic / high refractive index film and a transparent material laminate with an antistatic / antireflection film obtained by using the coating material. More specifically, the present invention relates to a display surface of a display device, a surface cover material thereof, a window glass, a glass for a show window, a display surface of a TV brown tube, a display surface of a liquid crystal device, a cover glass of an instrument, and a watch cover. Antistatic and high-refractive-reflective film forming paints useful for painting the surface of transparent materials that require antistatic and anti-reflection such as glass and the front image surface of CRT, and obtained by using it. The present invention relates to a transparent material laminate with an antistatic / antireflection film by combining an antistatic / high refractive index film layer and a low refractive index film layer.

【0002】

[Conventional technology]

Generally, it is known that a transparent material for displaying an image, for example, an image display portion of a TV cathode ray tube is easily charged with static electricity, and the static electricity causes dust to adhere to the display surface. It is also known that the image display surface reflects external light or an external image is projected on the image display surface, obscuring the image on the display surface.

【0003】

In order to solve the above problems, conventionally, a non-aqueous solvent dispersion of antimony-doped tin oxide (ATO) fine particles and a hydrolysis product of silicon alkoxide is applied to the surface of a transparent substrate. The antimony film layer is formed by drying, and a low refractive index film layer having a refractive index lower than that is formed on the antimony film. The refractive index of the conventional antistatic film layer is about n = 1.50 to 1.54, and the difference from the refractive index of the low refractive index film layer formed by the hydrolysis product (silica) of silicon alkoxide is small. Therefore, the antireflection property of the combination of the conventional antistatic film layer and the low refractive index film layer is insufficient.

【0004】

In order to solve the above problems, an antistatic film layer is made of a paint composed of a non-aqueous solvent dispersion containing a mixture of antimony-doped tin oxide fine powder and a hydrolysis product (silica) of silicon alkoxide as described above. Attempts have been made to form a low-refractive index film layer by applying a paint consisting of an aqueous dispersion of a hydrolysis product (silica) of silicon alkoxide on top of it, but the antireflection effect is sufficient. It wasn't.

【0005】

[Problems to be Solved by the Invention]

INDUSTRIAL APPLICABILITY The present invention relates to a coating material for forming an antistatic / high refractive index film having excellent antistatic properties on a transparent material surface, and a transparent material laminate with an antistatic / antireflection film obtained by using the same, particularly antistatic / antistatic coating. An object of the present invention is to provide a transparent material laminate having a high refractive index film layer and a low refractive index film layer formed on the high refractive index film layer.

【0006】

[Means for solving problems]

The present invention has been found to be able to solve the above problems by mixing black-based colored conductive fine powder with antimony-doped tin oxide fine powder, and has been completed based on this. That is, the coating material for forming an antistatic / high refractive index film according to the present invention is characterized by comprising a dispersion liquid containing a mixture of antimony-doped tin oxide fine powder and black-based colored conductive fine powder.

【0007】

Further, the transparent material laminate with an antistatic / antireflection film according to the present invention comprises a transparent base material, a fine powder of antimony-doped tin oxide on the surface of the transparent base material, and a black-based colored conductive fine powder. An antistatic / high refractive index film layer formed by applying and drying a paint consisting of a dispersion liquid containing a mixture of the above, and 0.1 than the refractive index of the antistatic / high refractive index film layer formed on the antistatic / high refractive index film layer. It is characterized by including a low refractive index film layer having the above low refractive index.

【0008】

In the mixture of the antimony-doped tin oxide fine powder and the black-based colored conductive fine powder used in the anti-static / high-refractive-index film-forming coating material of the present invention, the content of the black-based colored conductive fine powder and the antimony-doped The ratio of the content of the tin oxide fine powder is preferably 1 to 30:70 to 99. When the ratio of the content of the black-based colored conductive fine powder to the total weight of the mixture is larger than 30/70, the content of the black-based colored conductive fine powder becomes excessive, and the transparency of the obtained film layer is significantly lowered. When a laminated film is formed on the display surface of the display device, the visibility becomes extremely poor.

【0009】

Further, when it is less than 1/99, the conductivity of the obtained antistatic / high refractive index film layer does not increase, and light absorption hardly occurs, so that the antistatic / high refractive index film layer is above the antistatic / high refractive index film layer. In addition, even if the low refractive index film layer is formed, only the same antistatic and antireflection effects as those of the conventional one can be obtained, which is insufficient as an antistatic and antireflection film. The black-based colored conductive fine powder used in the present invention may be a fine powder having a color tone such as black, gray, black gray, and blackish brown, and having conductivity. For example, fine oxide powders such as carbon black, titanium black, metallic silicon, flowing tin, flowing mercury, metallic cobalt, and metallic tungsten, and metallic fine powder can be used. In particular, carbon black fine powder such as Ketjen black, furnace black, and graphite powder is preferable. The paint for forming an antistatic / high refractive index film using carbon black fine powder as the black colored conductive fine powder will be described below.

【0010】

In the conventional antistatic film-forming paint that does not contain black colored conductive fine powder, antistatic, high refractive index film layer conductivity, and high refractive index can be measured only by antimony-doped tin oxide fine powder. there were. However, in the present invention, by mixing the antimony-doped tin oxide fine powder with a black-based colored conductive fine powder having higher conductivity and light absorption ability, for example, carbon black fine powder, that is, By mixing with conductive fine particles (ATO) + black conductive fine particles, in other words, by adding double conductive fine particles, it is possible to apply antistatic and high refractive index film formation with better double antistatic properties. It has become possible to prepare liquids.

【0011】

Therefore, the antistatic / high refractive index film layer obtained by using the antistatic / high refractive index film layer forming coating film of the present invention exhibits an extremely excellent antistatic effect and an electromagnetic wave shielding effect. The antistatic / high refractive index film layer has a high refractive index of n = 1.55 to 2.0, and in order to reduce reflected light on the substrate surface, a refractive index difference of 0.1 or more is preferable. Shows extremely excellent antireflection property by providing a low refractive index film layer of 0.15 or more.

【0012】

That is, the reflected light from the surface of the low refractive index film layer can be canceled by the interference of the reflected light from the interface with the antistatic / high refractive index film layer having a high refractive index, and further, the high refractive index film layer can be formed. The existing carbon black particles can absorb the reflected light at the interface between the antistatic and high refractive index film layers. As a result, the antireflection effect can be enhanced more than before.

【0013】

Further, when the combination film of the antistatic / high refractive index film layer and the low refractive index film layer obtained by the present invention is formed on the display body surface such as a brown tube, not only the visibility is improved by the antireflection but also the display is performed. Since the body surface has a black color, the contrast of the image is also improved, which makes it possible to obtain a display body having excellent visibility.

【0014】

In the antimony-doped tin oxide fine powder used in the present invention, tin oxide is used in the vapor phase method (gassing the compound and cooling and solidifying it in the vapor phase) and the CVD method (gasifying the component elements and in the vapor phase). Both of these are reacted to cool and solidify the product) and the carbonate (or oxalate) method (the carbonate of the metal element or oxalate is transformed in the gas phase and cooled and solidified). It may be manufactured by a method. In addition, an acid-alkali method for producing an ultrafine sol of a target compound by mixing and reacting an aqueous solution of a fluoride of a component element and an aqueous solution of a basic compound, or a hydrothermal method for removing a solvent from the acid-alkali method is also used. It can be used for the production of fine powder. In the above hydrothermal method, fine particles can be grown, spheroidized, or surface modified. Further, the shape of the fine particles is not particularly limited, and may be spherical, needle-shaped, plate-shaped, chain-shaped, or the like.

【0015】

The method of doping tin oxide with antimony and the amount of antimony doped are not particularly limited, but are generally preferably 1 to 5% based on the weight of tin oxide. As a result, the tin oxide fine powder can further enhance its antistatic effect, electromagnetic wave shielding effect, and the like.

【0016】

The antimony-doped tin oxide fine powder used in the present invention preferably has an average particle size of 1 to 100 nm. If the average particle size is less than 1 nm, the electrical conductivity is lowered and the particles are likely to aggregate, making it difficult to uniformly disperse the particles in the paint, increasing the viscosity of the paint, and lowering the viscosity. Therefore, it is necessary to add a large amount of dispersion solvent, which may cause the concentration of the antimony-doped tin oxide fine powder in the paint to be excessively low.

【0017】

Further, when the average particle size of the antimony-doped tin oxide fine powder is larger than 100 nm, light is remarkably diffusely reflected by Rayleigh scattering in the obtained antistatic / high refractive index film layer, and the light appears white and the transparency is lowered.

【0018】

The particle size of the carbon black used is not particularly limited, but it is preferable to use a carbon black having a particle size of 1 μm or less from the viewpoint of dispersion stability of the coating material. Further, in order to disperse the carbon black fine powder, dispersants such as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can also be used.

【0019】

Furthermore, in order to fix antimony-doped tin oxide particles and carbon black particles on the substrate, inorganic binders such as silicone oil and silicone alkoxide hydrolyzate, and organic resins such as acrylic resin, urethane resin and epoxy resin are used. Binder may be added. However, in this case, in order to obtain the desired conductivity, it is necessary to carry out a preliminary test in which the weight ratio of (binder) / (conductive powder) is changed and select as appropriate.

【0020】

The dispersant and the binder can also be used when black colored conductive fine particles other than carbon black particles are used. In the laminate of the present invention, there is no particular limitation on the thickness or weight of the antistatic / high refractive index film layer formed on the transparent substrate, but it is generally preferable to have a thickness of 0.05 to 0.5 μm.

【0021】

A low refractive index film layer is formed on the antistatic / high refractive index film layer formed by using the coating material of the present invention. The low-refractive-index film layer is effective in filling voids on the surface of the antistatic / high-refractive-index film layer, suppressing diffused reflection, and improving its friction resistance. The low refractive index film layer can be formed by applying a coating material consisting of a non-aqueous solvent solution containing silicon alkoxide on the antistatic / high refractive index film layer, drying it, and baking it.

【0022】

The silicon alkoxide used in the coating material for forming a low refractive index film layer can be selected from a tetraalkoxysilane compound, an alkyltrialkoxysilane compound, a dialkyldialkoxysilane compound and the like, and the non-aqueous solvent is an alcohol-based compound. It can be selected from compounds, glycol ether compounds, ester compounds, ketone compounds and the like. These may be used as a single species or as a mixture of two or more species.

【0023】

When the above paint is applied onto an antistatic / high refractive index film layer, dried, and baked, the silicon alkoxide hydrolysis product becomes silica. The refractive index of silica is n = 1.46, which is lower than the refractive index of antimony-doped tin oxide. However, in order to increase the difference in refractive index between the antistatic / high refractive index film layer and the low refractive index film layer, It is preferable to use a substance having a lower refractive index and higher transparency than silica.

【0024】

In the present invention, it is preferable that the silicon alkoxide-containing coating material further contains magnesium fluoride (n = 1.38) fine powder. The content of magnesium fluoride fine powder in the low-refractive-index film layer is not particularly limited and can be appropriately adjusted according to the corresponding antistatic / high-refractive-index film layer composition. It is preferably in the range of 0.01 to 80% with respect to the weight of the silicon alkoxide (SiO2 equivalent).

【0025】

The magnesium fluoride fine powder used for forming the low refractive index film layer preferably has an average particle size of 1 to 100 nm. When the average particle size is larger than 100 nm, light is diffusely reflected by Rayleigh scattering in the obtained low refractive index film layer, and the low refractive index film layer may appear whitish and its transparency may decrease. Further, if the average particle size of the magnesium fluoride fine powder is less than 1 nm, the fine particles tend to aggregate, which makes it difficult to uniformly disperse the fine particles in the paint, causing problems such as an excessive viscosity of the paint. .. Further, if the amount of the solvent used is increased in order to reduce the viscosity of the paint, there arises a problem that the concentrations of magnesium fluoride fine powder and silicon alkoxide in the paint are lowered.

【0026】

The magnesium fluoride fine powder used in the present invention can be produced by a known method such as a vapor phase method, a CVD method, a carbonate method or an oxalate method. In addition, the acid-alkali method for producing an ultrafine sol of the target compound by mixing and reacting an aqueous solution of a fluoride of a component element and an aqueous solution of a basic compound, or a hydrothermal method for removing a solvent from the acid-alkali method is also used. It can be used in the production of powder. In the above hydrothermal method, fine particles can be grown, spheroidized, or surface modified. The shape of the fine particles may be spherical, needle-shaped, plate-shaped, chain-shaped, or the like.

【0027】

In the present invention, the thickness of the low refractive index film layer is not particularly limited, but preferably has a thickness of 0.05 to 0.5 μm. Since the low refractive index film layer having a thickness in the above range is relatively thin, even if it covers the antistatic / high refractive index film layer, the conductivity of the antistatic / high refractive index film layer Due to its properties, it is possible to exhibit practically sufficient antistatic property and electromagnetic wave shielding property as a whole.

【0028】

The transparent substrate used in the present invention can be selected from a glass material, a plastic material, and the like.

【0029】

[Example]

Hereinafter, the present invention will be described in detail with reference to the following examples. Needless to say, the present invention is not limited to the following examples. (Example 1) (1) The antistatic / high refractive index film layer forming paint (A) was adjusted as follows (carbon black / antimony-doped tin oxide = 10/90 weight ratio). 1.8 g of antimony-doped tin oxide fine powder (manufactured by Sumitomo Cement Co., Ltd.), 0.2 g of carbon black fine powder (manufactured by Mitsubishi Kasei Co., Ltd .: trademark MA-7), and 0.2 g of anionic surfactant (manufactured by Kao Co., Ltd.) : Trademark Poise 521) was added to a mixed solution of 77.8 g of water, 10 g of ethanol, and 10 g of ethyl cellosorb, and then dispersed with an ultrasonic homogenizer (manufactured by Central Scientific Co., Ltd .: Sonifire 450) for 10 minutes to obtain a uniform dispersion. ..

【0030】

(2) A paint for forming a low refractive index film layer (a) was prepared by the following operation. That is, 0.8 g of tetraethoxysilane, 0.8 g of 0.1N hydrochloric acid, and 99.2 g of ethyl alcohol were mixed to prepare a uniform solution.

【0031】

(3) Manufacture of laminate The paint (A) was applied on one surface of a glass substrate at a temperature of 40 ° C. by a spin coating method, and dried with warm air at 50 ° C. for 3 minutes. An antistatic / high refractive index film layer having a thickness of 0.1 μm was formed. Next, the paint (a) was applied on the antistatic / high refractive index film layer of this glass substrate by the spin coating method at a temperature of 40 ° C, and dried with warm air at 50 ° C. A low refractive index film layer having a thickness of 0.1 μm was formed by baking at ° C for 20 minutes.

【0032】

(4) Test Total light transmittance, surface reflectance (according to surface reflectance), surface reflectance (using a normal reflection jig with an incident angle of 5 degrees) of the transparent material laminate obtained as described above, wavelength 550 nm by a spectrophotometer. The single-sided value of the light reflectance was measured.) And the adhesion between the antistatic / high refractive index film layer and the low refractive index film layer (erasable rubber test, load 1 kg, reciprocating 20 times) was measured. The test results are shown in Table 1.

【0033】

(Example 2) The same operation as in Example 1 was performed. However, carbon black / antimony-doped tin oxide = 1/99 (weight ratio) in the antistatic / high refractive index film layer forming paint was used. The test results are shown in Table 1.

【0034】

(Example 3) The same operation as in Example 1 was performed. However, carbon black / antimony-doped tin oxide in the antistatic / high refractive index film layer forming paint was set to 20/80 (weight ratio). The test results are shown in Table 1.

【0035】

(Example 4) The same operation as in Example 1 was performed. However, carbon black / antimony-doped tin oxide in the antistatic / high refractive index film layer forming paint was set to 30/70 (weight ratio). The test results are shown in Table 1.

【0036】

(Example 5) The same operation as in Example 1 was performed. However, instead of the low refractive index film layer forming paint (a), the paint (b) prepared as follows was used. That is, 0.4 g of magnesium fluoride fine powder (manufactured by Sumitomo Cement Co., Ltd., particle size: 10 to 20 nm) was mixed with 0.6 g of tetraethoxysilane, 10 g of water, 0.6 g of 0.1N hydrochloric acid, and 89 g of ethyl alcohol. It was evenly dispersed. The test results are shown in Table 1.

【0037】

(Comparative Example 1) The same operation as in Example 1 was performed. However, carbon black / antimony-doped tin oxide = 0/100 (weight ratio) in the antistatic / high refractive index film layer forming paint was set. That is, it was assumed that the carbon black fine powder was not contained. The test results are shown in Table 1. (Comparative Example 2) The same operation as in Example 2 was performed. However, carbon black / antimony-doped tin oxide in the antistatic / high refractive index film layer forming paint was set to 40/60 (weight ratio). The test results are shown in Table 1.

【0038】

[table 1]

<img file="JPH0680903A_D0001.tif" />【0039】

As is clear from the test results shown in Table 1, it consists of a dispersion containing a transparent substrate and a mixture of 70 to 99 parts by weight of antimony-doped tin oxide fine powder and 1 to 30 parts by weight of carbon black fine powder. An antistatic / high refractive index film layer formed from an antistatic / high refractive index film forming coating, and a refractive index formed on the antistatic / high refractive index film layer and having a refractive index lower than the refractive index by 0.1 or more. A transparent material laminate with an antistatic / antireflection film comprising a low refractive index film layer having a display surface of a display device, its surface cover material, window glass, show window glass, and a display surface of a TV brown tube. As a display surface of a liquid crystal device, a cover glass of an instrument, a cover glass of a clock, and a front image surface of a CRT, the double layer has sufficient light transmission, low surface resistance and low refractive index, and is sufficiently practical. It can have an antistatic function and an antireflection function. Further, by dispersing and containing magnesium fluoride fine powder in the low refractive index film layer, the antireflection function of the transparent material laminate with antistatic / antireflection film can be improved.

【0040】

[Effect of the invention]

The antistatic / high refractive index film-forming coating material according to the present invention makes it possible to easily form a film layer having excellent antistatic properties and a high refractive index on a transparent substrate, and in particular, this By combining the low refractive index layer with the antistatic / high refractive index film layer obtained using the above, it has become possible to provide a transparent material laminate with an antistatic / antireflection film having excellent practical performance. That is, by using a paint containing an antimony-doped tin oxide fine powder and a black-based colored conductive fine powder, that is, a paint containing two types of conductive fine particles, a charge having a high antistatic function and a high refractive index can be obtained. Prevention A high refractive index film layer can be obtained. Then, by combining the antistatic / high refractive index film layer and the low refractive index layer, a transparent material laminate with an antistatic / antireflection film having excellent antistatic property and antireflection property can be obtained.