JPH0748140A - Production of glass sharply cutting ultraviolet rays - Google Patents

Abstract

PURPOSE:To improve the shielding performance and transmittance of visible light by heat-treating a specific raw glass to precipitate fine particles of CuCl and/or CuBr. CONSTITUTION:A raw glass to be used in this process has a glass composition composed of 62-85mol% of SiO2, 10-20mol% of B2O3, 1-10mol% of Al2O3, 3-15mol% of Li2O+Na2O+K2O, 0.01-2mol% of copper oxide in terms of Cub, 0.01-4mol% of Cl+Br, 0.001-0.5mol% of iron oxide in terms of Fe2O3 and 0.01-3mol% of tin and antimony oxides in terms of SnO+Sb2O3. The raw glass is melted by heating at 1200-1800 deg.C for 5min to several days, formed to a desired form, cooled to room temperature, heated again and maintained at a prescribed temperature to precipitate Curl and/or CuBr fine particles having particle diameter of 0.5-400nm and obtain a glass having a sharp UV-cutting property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an ultraviolet sharp cut glass.

[0002]

2. Description of the Related Art Heretofore, as glass for cutting off ultraviolet rays, there have been known ones which are commercially available as so-called ultraviolet sharp cut glasses and cover glasses for protecting solar cells of artificial satellites from ultraviolet rays. These glasses shield ultraviolet rays by utilizing the absorption in the ultraviolet region of glasses doped with various ions.

[0003]

However, in the glass doped with these ions, the rate of change of the transmittance with respect to the wavelength near the ultraviolet absorption edge is relatively gradual.
In order to cut near-ultraviolet rays, absorption in the visible region is unavoidable, and the glass is colored yellow, and conversely, there is a problem that the near-ultraviolet region cannot be cut with colorless glass that does not absorb in the visible region. .

Further, for the purpose of eliminating this drawback, Japanese Patent Publication No. 46-3464 proposes an ultraviolet absorbing glass having a small wavelength inclination width. This glass is characterized by precipitating CuCl or CuBr crystals in the glass, but the chemical durability of the glass is insufficient, or even if the glass has good chemical durability, the glass is blue or green. There was a problem that it was colored red.

[0005]

The present invention has been made to solve the above-mentioned problems, and the composition of the glass is expressed as mol% SiO ₂ 62 to 85% B ₂ O ₃ 10 to 20% Al. ₂ O ₃ 1 to 10% Li ₂ O + Na ₂ O + K ₂ O 3 to 15% Copper oxide in terms of CuO 0.01 to 2% Cl + Br 0.01 to 4% Iron oxide in terms of Fe ₂ O ₃ the oxide of 0.001 to 0.5% tin and antimony preparing a raw glass consisting from 0.01 to 3% by SnO + Sb ₂ O ₃ in terms of, by heat-treating raw glass, C
It is a method for producing an ultraviolet sharp cut glass in which uCl or / and CuBr fine particles are deposited.

The ultraviolet sharp cut glass produced by the present invention absorbs light in the visible region because CuCl and / or CuBr fine particles (crystals) having extremely sharp absorption in the ultraviolet region are deposited in the glass. It is possible to selectively block only ultraviolet rays without doing so.

The present invention prepares CuCl and / or CuBr fine particles by preparing the elementary glass having the above-mentioned specific composition and heat-treating it. First, the reason for limiting the composition of the raw glass will be described.

In the raw glass of the present invention, SiO
_{When 2} is less than 62 mol%, clouding of the glass or coloring due to copper colloid is likely to occur due to the phase separation of the glass, and when it exceeds 85 mol%, the glass formation temperature becomes high and Cu, Cl
And, the volatilization of Br component is increased.

When B ₂ O ₃ is less than 10 mol%, CuC
l, it is difficult to obtain CuBr precipitation, and if it exceeds 20 mol%,
The chemical durability of glass becomes low.

When Al ₂ O ₃ is less than 1 mol%, the glass tends to become cloudy due to phase separation, and when it exceeds 10 mol%, vitrification is difficult.

Li ₂ O, Na ₂ O and K ₂ O may be used alone or in combination of two or more. When the total amount is less than 3 mol%, the glass formation temperature becomes high and the volatilization of Cu, Cl, and Br components increases, and the total amount becomes 1
If it exceeds 5 mol%, the copper colloid will be precipitated in the glass to easily turn red and the chemical durability will be low.

Further, CuCl and / or C is contained in the glass.
In order to deposit uBr fine particles, copper oxide was added to CuO.
Converted to 0.01 to 2 mol%, Cl or / and Br to 0.
It is necessary to contain 01 to 4 mol%.

When the copper oxide converted to CuO is less than 0.01 mol%, CuCl and / or CuBr fine particles are not sufficiently deposited and the ultraviolet ray shielding performance is not sufficient. No improvement, and conversely CuCl
Alternatively, giant particles of CuBr fine particles are deposited, and the transparency of the glass is lost. The mixing ratio of Cl and Br is appropriately selected depending on the shielding wavelength.

When the total amount of Cl and Br is less than 0.01 mol%, CuCl and / or CuBr fine particles are not sufficiently precipitated and the ultraviolet ray shielding performance is not sufficient. There is a risk that the glass does not improve, and conversely the glass is likely to undergo phase separation, and the transparency of the glass is lost. Cl and Br may be used alone.

Further, it is necessary to contain 0.001 to 0.5% of Fe ₂ O ₃ -converted iron oxide in order to prevent reddening due to copper colloid deposition in the glass. When the iron oxide calculated as Fe ₂ O ₃ is less than 0.001 mol%, the copper colloid precipitation is not sufficiently suppressed and the glass tends to turn red, and when it exceeds 0.5%, the glass is colored brown or green. Resulting in.

In addition to the above components, by containing 0.01 to 3 mol% of tin and antimony oxides in terms of SnO + Sb ₂ O ₃ , the glass is not colored and CuCl and / or CuBr fine particles are further precipitated. It will be easier. Sn
If the oxide of tin and antimony converted to O + Sb ₂ O ₃ is less than 0.01 mol%, the glass tends to be colored blue or green, and if it exceeds 3 mol%, the glass tends to be colored red, which is not preferable.

Of these ranges, SiO ₂ 6
3 to 82 mol%, B ₂ O ₃ 12 to 18 mol%, Al ₂
O ₃ 1.5 to 8 _{mol%, Li 2 O + Na 2} O + K 2 O
4 to 13 mol%, CuO equivalent copper oxide 0.1
2 mol%, Cl or / and Br 0.1 to 3 mol%, F
A glass composed of 0.002 to 0.05 mol% of iron oxide converted to e ₂ O ₃ and 0.05 to 2 mol% of tin and antimony oxide converted to SnO + Sb ₂ O ₃ has a colorless and transparent appearance. With controlled particle size CuCl or /
And CuBr fine particles are particularly preferable because they can be easily deposited.

As components other than the above, CaO and Mg are used for the purpose of controlling the solubility, durability and thermal characteristics of the glass.
You may contain alkaline-earth components, such as O and BaO.

The particle size of the CuCl and / or CuBr fine particles to be precipitated is preferably 0.5 to 400 nm. If the particle size is less than 0.5 nm, CuCl and / or Cu
The absorption of Br is not sufficient and the expected shielding of ultraviolet rays is insufficient. If it exceeds 400 nm, visible light is scattered in the glass and the transparency of the glass is lost, which is not preferable. A particle size of 1 to 100 nm in this range is particularly preferable because it sufficiently shields ultraviolet rays and makes the glass transparent to visible light.

Examples of raw materials used in the production of the ultraviolet sharp cut glass of the present invention include the following substances.

As the silicon raw material, for example, a silicon oxide such as silicon dioxide, a nitride, an organic silicon compound, or a silicate such as an alkali silicate may be mixed with another alkali compound.

Boric acid (H ₃ BO) is used as a boric acid raw material.
₃ ), oxides such as boric anhydride (B ₂ O ₃ ), nitrides, organoboron compounds, and borate salts such as alkali borate may be mixed with other alkali compounds.

As the aluminum raw material, hydroxides and oxides such as aluminum hydroxide (Al (OH) ₃ ) and alumina (Al ₂ O ₃ ) as well as nitrides and organoaluminum compounds can be used.

Typical examples of the alkali metal raw material are carbonates, but other alkali compounds such as hydroxides and chlorides can be appropriately used.

As the raw materials for copper, chlorine and bromine, for example, copper chlorides and bromides such as CuCl, CuCl ₂ , CuBr and CuBr ₂ can be used. Further, as the copper raw material, simple copper or an inorganic salt or organic salt such as copper oxide, hydroxide, or sulfate may be used. As the chlorine and bromine raw materials, alkali chlorides, alkali bromides, ammonium chloride and ammonium bromide can be used, and chlorides and bromides of other additive components can also be supplied. Further, chlorine and bromine can be introduced as a simple substance or as a gas of chloride or bromide by reacting with glass.

As a raw material of iron, iron simple substance, iron oxide,
A halide or the like can be used.

As a raw material of tin, stannous oxide (Sn) is used.
O), stannic oxide (SnO ₂ ) and other oxides, as well as chlorides and organotin compounds may be used.

As a raw material of antimony, antimony trioxide (Sb ₂ O ₃ ) and antimony pentoxide (Sb ₂ O ₅ ) are used.
In addition to oxides such as and complex oxides such as sodium pyroantimonate, chlorides and organic antimony compounds can also be used.

The means for producing the ultraviolet sharp cut glass of the present invention is not particularly limited, and for example, various raw materials are weighed and mixed in a predetermined amount, and the mixture is heated and melted at 1200 to 1800 ° C. for 5 minutes to several days, and then predetermined. A method of forming into a shape is used. As a method for depositing CuCl or / and CuBr fine particles, the molded glass is once cooled to room temperature and then heated to be maintained at a predetermined temperature to deposit fine particles, and a cooling process up to the temperature for molding or after molding. In the process of cooling the glass to room temperature, keep it at a predetermined temperature,
There is a method of depositing fine particles by controlling the cooling rate, and both methods are preferable.

The ultraviolet sharp cut glass produced by the present method is essentially free from phase separation and coloring of the glass even in the cooling process from the melt state, so that the pressing method, the roll-out method, the float method, the Danner method, etc. It is possible to mold glass into a predetermined shape in various methods and atmospheres.

[0031]

【Example】

Examples 1 to 14 (Examples) 400 g of glass having the composition (unit: mol%) shown in Tables 1 and 2
Mix the raw materials so that it becomes and put it in a platinum crucible.
It was melted at 50 ° C. for 2 hours. Then, this was poured onto a stainless plate to form a plate-shaped glass. This shaped glass is heat-treated at the heat treatment temperature (unit: ° C) and heat treatment time (unit: minutes) shown in the table, or cooled to the glass transition temperature or lower at the cooling rate (unit: ° C / min) shown in the table. By performing the above, fine particles were deposited in the glass.

While observing the appearance of this fine particle-deposited glass, it was polished to a thickness of 1 mm and the spectral transmittance was measured.
The wavelength showing 50% transmittance (unit: nm) and the wavelength inclination width (unit: nm) at which the transmittance changes from 80% to 10% were determined. The particle size (unit: nm) of fine particles in glass was measured by observation with a transmission electron microscope. Appearance and other measured values are shown in the same table.

Examples 21 to 23 (Comparative Examples) Glasses having the compositions shown in Table 2 were prepared in the same manner as in Examples,
The appearance was observed and the spectral transmittance was measured. The results are shown in Table 2. These glasses were colored red or brown due to absorption of copper colloid generated in the glass at around 570 nm, and were opaque due to the phase separation of the glass.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

EFFECTS OF THE INVENTION According to the present invention, a colorless glass is produced because it has an excellent ultraviolet ray shielding performance and a high transmittance in the visible region.

Claims (2)

[Claims] 1. A glass composition in terms of mol% SiO ₂ 62 to 85% B ₂ O ₃ 10 to 20% Al ₂ O ₃ 1 to 10% Li ₂ O + Na ₂ O + K ₂ O 3 to 15% Copper oxide 0.01 to 2% in terms of CuO Cl + Br 0.01 to 4% 0.001 to 0.5% in terms of Fe ₂ O ₃ oxide of iron ₂ to 0 in terms of SnO + Sb ₂ O ₃ of oxides of tin and antimony Prepare a raw glass consisting of 0.01 to 3%, heat-treat the raw glass, and add C
A method for producing an ultraviolet sharp cut glass in which uCl or / and CuBr fine particles are deposited. 2. The method for producing an ultraviolet sharp cut glass according to claim 1, wherein the CuCl and / or CuBr fine particles to be precipitated have a particle size of 0.5 to 400 nm.