JPH1081545A - Glare-proof glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glare-proof glass that has an excellent glare-proof function, and is dust-free and easy to remove dust even if the dust attaches to the glass, and can be thermally reinforced, by applying a special paste to a transparent plate glass. SOLUTION: This glare-proof glass comprises transparent plate glass and a light-diffusive coating of a paste that contains glass powder of a low melting point and a thermally resistant inorganic filler and is applied to at least one face of the plate glass to form the light-diffusive coating of 0.5μm or less surface roughness (Ra). The paste is prepared so as to make the weight ratio of the thermally resistant inorganic filler having an average particle size of 2μm or less and Mohs hardness of 8 or less to the glass powder of a low melting point (5:95) to (20:80). This glare-proof glass is preferably prepared by coating transparent plate glass having coefficient of thermal expansion (α1) of 80-90×10<-7> / deg.C with the paste that provides a light-diffusive coating film of coefficient of thermal expansion (α2) of 45-75×10<-7> / deg.C (where α1>=α2×1.1), heating the glass, and then cooling the glass rapidly to form the reinforced plate glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an excellent anti-glare function,
The present invention relates to an antiglare glass to which dirt such as dust hardly adheres and which can be easily removed even if dirt adheres, and which can be thermally strengthened.

[0002]

2. Description of the Related Art Conventionally, there is known an anti-glare glass in which a glass plate surface is damaged by sandblasting or the like and the damaged surface is eroded with a hydrofluoric acid-based liquid.

However, dirt such as dust easily adheres to the rough surface formed as described above, and it is difficult to remove the adhered dirt. Further, in the case of thermal strengthening, a desired surface compressive stress is not generated on the rough surface portion, and thus the strengthening becomes insufficient.

Japanese Utility Model Publication No. 40-20632 discloses a diffused colored light bulb in which a colored transparent low melting point glass is coated on the surface of a glass bulb and fine glass powder having a high softening point and a different refractive index is dispersed therein. Have been. JP-A-56-41856 discloses that a frosted glass is prepared by coating a low-melting glass and a glass enamel paste or a slip containing a glass powder having a different refractive index, a silica powder, or an alumina powder on a transparent glass material and baking it. A process for producing the resulting frosted glass is disclosed.

In these known techniques, only a light-scattering film is simply formed, and dirt such as dust is hardly adhered, and even if dirt is adhered, it is easy to remove, and heat-enhancing anti-glare which can be thermally strengthened. No technique for obtaining glass is described or suggested.

JP-A-56-155029 filed by the present applicant
In No. 2, after forming a colored layer with a paste having a low-melting glass frit on the surface of a sheet glass, heating and sintering it to produce a reinforced sheet glass, the linear expansion coefficient ratio of the low-melting glass frit to the sheet glass is determined. A method for producing a tempered glass sheet having a colored layer of 0.5 to 0.8 was proposed.

In the proposed example, a colored decoration is applied to a glass plate, which is different from a method in which a light-scattering film is formed. Also, no technique has been proposed which makes it difficult for dirt such as refuse to adhere thereto and makes it easy to remove even if dirt adheres.

On the other hand, the present invention provides an anti-glare glass which is excellent in anti-glare function as described above, hardly adheres dirt such as dust, can be easily removed even if dirt adheres, and can be thermally strengthened. Is what you do.

[0009]

According to the present invention, there is provided an anti-glare method in which a paste containing a low-melting glass powder and a heat-resistant inorganic filler is applied to at least one surface of a transparent glass plate and heated to form a light-scattering film. In glass, the weight ratio of heat-resistant inorganic filler / low-melting glass powder is 5/95 to 20/80.
And the heat-resistant inorganic filler has an average particle size of 2 μm.
m and a Mohs hardness of 8 or less, and the light-scattering film has an antiglare glass prepared to have a surface roughness (Ra) of 0.5 μm or less. In the antiglare glass, the thermal expansion coefficient (α1) of the transparent glass plate There to 80-90 × 10 ^{over 7} / ° C., the thermal expansion coefficient of the diffusive coating made of a low-melting-point glass powder and heat-resistant inorganic filler ([alpha] 2) is 45 to 75 × 10 ^{over 7} / ° C. (although [alpha] 1 ≧ alpha
2 × 1.1), a paste containing the low-melting glass powder and a heat-resistant inorganic filler was applied to a transparent glass plate, heated and quenched to obtain a reinforced glass, and further, the heat-resistant inorganic filler was silica, Being tin oxide or zirconia.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the antiglare glass of the present invention, the transparent glass plate is a general glass widely used, such as soda-lime-silica glass and aluminosilicate glass, but is not limited thereto. Absent. In addition, colorless or colored transparent glass can be appropriately used, or bent plate glass or the like can be used. Although the thickness of the glass plate is not specified, a thickness of several mm to several tens of mm can be adopted, and particularly, from 3 to 12 mm from the viewpoint of handling workability and convenience.
Is often used.

As the low-melting glass, various known and publicly available glass compositions can be adopted, but PbO—SiO ₂ —
B ₂ O ₃ system, PbO -B ₂ O ₃ -ZnO-based, ZnO -SiO ₂ -B ₂ O ₃ system, Bi
There are _{2 0 3 -SiO 2 -B 2 O} 3 based glass. Among these glasses, the softening point of the transparent glass is on the order of 700 ° C., whereas the softening point of the low-melting glass is around 600 ° C. or lower.

In order to exhibit the light scattering function, the heat-resistant inorganic filler employs an inorganic material such as glass or ceramic having a different refractive index from that of the low-melting glass, or an inorganic material exhibiting opalescent irregular reflection. Nor.
In the present invention, the term "heat resistance" means a material having a higher melting point or softening point than that of a low melting point glass. In particular, the heat-resistant inorganic filler must be a material having an average particle size of 2 μm or less and a Mohs hardness of 8 or less.

When the average particle size exceeds 2 μm, the particle size is excessively large, so that the surface of the resulting light-scattering film has irregularities, and the antifouling property is impaired. In addition, it is difficult to obtain gentle and uniform light scattering throughout. Preferably, those having a thickness of 0.1 μm to 1 μm are employed. On the other hand, when the Mohs' hardness exceeds 8, filler particles projecting from the light-diffusing film may damage the wiping material such as felt for cleaning, and the cuttings and the like may be attached to spread the contamination.

As heat-resistant inorganic fillers which meet the above conditions, are easily available and are inexpensive, silica having a Mohs hardness of 7,
Tin oxide with a Mohs hardness of 6 to 7 and zirconia with a Mohs hardness of 6.5 can be recommended.

The ratio of the heat-resistant inorganic filler / low-melting glass powder is 5 wt% / 95 wt% if the whole is 100 wt%.
To 20 wt% / 80 wt%. If the heat-resistant inorganic filler is less than 5% by weight, it is difficult to obtain an effective light scattering property. On the other hand, if it exceeds 20% by weight, the light scattering property is high but the total light transmittance is reduced. Further, irregularities become conspicuous on the surface of the light-scattering film, the antifouling property decreases, and the chemical resistance also decreases.

A colored antiglare glass can be obtained by further using a small amount (5 wt% or less) of a heat-resistant coloring pigment in addition to the low-melting glass powder and the heat-resistant inorganic filler. For example, to obtain a blue color, a cobalt oxide-aluminum oxide pigment, to obtain a green color, a copper oxide-chromium oxide-manganese oxide pigment, and to obtain a yellow color, a titanium oxide-antimony oxide-lead oxide type Known pigments such as pigments can be used.

When forming the light-scattering film, a low-melting glass powder, a heat-resistant inorganic filler, or a coloring pigment is used, and these are used as alcohols such as methanol and propanol, oils such as pine oil and caster oil, ethyl cellulose, rosin, and the like. A paste is prepared by mixing butyl carbitol, various glycols, various resins, and the like in a suitable combination of paste oils, and the paste is formed on a glass plate by a suitable coating means such as flow coating, spin coating, brush coating, roller coating, or screen printing. Apply to. Of course, it may be applied to the entire surface of the glass plate, or may be applied in a design pattern. As a suitable coating means, a screen printing method can be mentioned, according to which a film having a uniform film thickness can be obtained and the pattern can be easily applied. In order to efficiently obtain a film having a uniform film thickness at a low cost, a curtain flow coating method can be recommended.

The viscosity of the paste is appropriately considered depending on the application means, the thickness of the light-scattering film to be obtained, and the like. For example, if a film having a film thickness of about 10 to 20 μm is to be obtained by screen printing, about several hundred poise is required. It is appropriate to use a viscosity of several poise to 10 poise or less if a film thickness of about 3 to 10 μm is to be obtained by curtain flow coating.

It is preferable that the light-scattering film is as thin as possible and has a light scattering effect. However, if the thickness is too small, it is difficult to uniformly coat the glass plate. desirable.

After application of the paste, the paste is dried, heated to about 600 to 650 ° C. in a heating furnace, and cooled to obtain an antiglare glass.

In the present invention, it is more preferable that the antiglare glass is a heat-strengthened glass. In this case, the thermal expansion coefficient (α1) of a general transparent glass plate [room temperature to 300 ° C .; 80-90 × 10
^-7 / ° C, the coefficient of thermal expansion (α) of the light-diffusing coating composed of low-melting glass and heat-resistant inorganic filler
2) is 45 to 75 × 10 ^{over 7} / ° C. range (where α1 ≧ α2 × 1.
1). If the low-melting-point glass and the heat-resistant inorganic filler have a thermal expansion coefficient equal to or higher than that of the transparent glass plate, the light-scattering film may be cracked or peeled off from the transparent glass plate. In order to prevent such cracking and peeling, it is necessary that α1 ≧ α2 × 1.1. In addition, thermal expansion coefficient of practical low melting point glass is 45 × ^10-7 / ℃
Nothing less is known.

The aforementioned low melting point glass of PbO—SiO ₂ —B ₂ O
₃ system, PbO -B ₂ O ₃ -ZnO-based, ZnO -SiO ₂ -B ₂ O ₃ system, Bi ₂ 0 ₃
In the -SiO ₂ -B ₂ O ₃ -based glass, a desired thermal expansion coefficient can be selected from the component ratio, and the thermal expansion coefficient of silica in the heat-resistant inorganic filler is 5 × 10 ⁻⁷ / ° C.
Tin oxide is 38 × 10 ⁻⁷ / ° C., and zirconia is 80 × 10 ⁻⁷ / ° C., and those in the above range can be obtained by appropriately combining the low-melting glass and the heat-resistant inorganic filler.

The strengthened anti-glare glass is easily obtained by applying a paste containing a low-melting glass powder and a heat-resistant inorganic filler to a transparent glass plate, heating and forming a fused coating layer, and rapidly cooling the same. It is not necessary to provide a step of heating and quenching again for strengthening. Also,
It is also possible to perform a bending operation when heated, thereby obtaining a reinforced bent antiglare glass.

In the present invention, it is preferable that the total light transmittance is 50% or more.
For example, if it is used as a window in a building, the interior can be made evenly bright. The light scattering rate (haze value) is 20
The range is preferably about 90%, and a desired haze can be selected in consideration of privacy, such as windows and partitions in bathrooms, restrooms, and private rooms.

The antiglare glass according to the present invention can be used as a laminated glass or a multi-layer glass in which one is the antiglare glass and the other is a normal transparent glass, or a laminated glass in which antiglare glasses are combined. It can also be a double glazing. In the case of these laminated glass and double glazing,
The light-scattering coating may be disposed on the outer surface of one and / or the other glass plate, and may be disposed on the inner surface thereof.

[0026]

【Example】

[Example I] (Preparation of antiglare glass) As a transparent glass plate, a normal soda-lime glass having a thickness of 6 mm and a size of 400 mm □ by a float method was used. PbO − as low melting glass powder
Adopted SiO ₂ -B ₂ O ₃ based glass, silica powder as a heat-resistant inorganic filler, tin oxide powder, zirconia powder, employing alumina powder (Comparative Example).

Table 1 shows the characteristics of the transparent glass plate, the low-melting glass powder, and the heat-resistant inorganic filler.

A liquid obtained by mixing water, methanol, hexanol, and a cellulose resin was used as the paste oil.
The mixture of the heat-resistant inorganic powder and the low-melting glass in a desired ratio is further mixed with paste oil and kneaded to obtain a viscosity of 4 ±
A 1-poise light-scattering coating paste was prepared. This was applied to one surface of a transparent glass plate by a flow coating method, dried, then heat-treated at 630 ° C. for about 10 minutes in a heating furnace, and cooled to obtain an antiglare glass.

(Test) The thickness of the obtained antiglare glass was measured by a micrometer. The average coefficient of thermal expansion from room temperature to 300 ° C is measured by a thermal dilatometer, the total light transmittance and the light scattering rate (haze value) are measured by a haze meter,
The center line average roughness (Ra) was determined by a surface roughness meter.

Further, a nonwoven fabric (Bencott P) folded five times is pressed against the surface of the light-scattering coating film, and reciprocated on the film surface ten times by hand, and the adhesion of the nonwoven fabric to the film surface is visually observed. , Not dirty = 1 rank, slightly dirty =
Evaluation was made in three ranks of 2 ranks and those with noticeable dirt = 3 ranks.

Table 2 shows the results.

[0033]

[Table 1]

[0034]

[Table 2]

(Results) As is evident from Table 2, in the examples according to the present invention, both the light transmittance and the haze value are good, the surface roughness is low and smooth, and the best results are obtained also with respect to the resistance to contamination. Is shown.

[0036]

Example II Samples corresponding to Examples 1 and 3 of Example I were prepared, except that a paste was applied, heated and then air-cooled to complete a tempered antiglare glass. In these samples, cracks and peeling of the light-scattering film, warpage of the glass plate, etc. were not observed,
Good appearance was shown.

A bending strength test was conducted on the two types of the tempered anti-glare glass. The fracture stress in the ring in-plane strength test was 3220 kg / cm ² , 3250
kg / cm ² . On the other hand, the one not strengthened is 1400 kg / cm ²
The reinforced anti-glare glass exhibits extremely excellent strength.

[0038]

According to the present invention, both the total light transmittance and the light scattering rate (haze value) are good, the stains are less likely to occur, and an excellent strength in heat strengthening is obtained.

Claims (3)

[Claims] 1. An antiglare glass in which a paste containing a low-melting glass powder and a heat-resistant inorganic filler is applied to at least one surface of a transparent glass plate and heat-treated to form a light-scattering film, the heat-resistant inorganic filler / The weight ratio of the low-melting glass powder is in the range of 5/95 to 20/80, the heat-resistant inorganic filler has an average particle size of 2 μm or less, a Mohs hardness of 8 or less, and the light-scattering film has a surface roughness (Ra). ) Is 0.5μm
An anti-glare glass prepared as follows. 2. The transparent glass plate has a coefficient of thermal expansion (α1) of 80 to 90.
× to 10 ^{@ 7} / ° C., the thermal expansion coefficient of the diffusive coating made of a low-melting-point glass powder and heat-resistant inorganic filler ([alpha] 2) is 45
75 × 10 ⁻⁷ / ° C (α1 ≧ α2 × 1.1), paste containing the above-mentioned low melting point glass powder and heat resistant inorganic filler on a transparent glass plate The anti-glare glass according to claim 1, wherein: 3. The antiglare glass according to claim 1, wherein the heat-resistant inorganic filler is silica, tin oxide or zirconia.