JP2003095691A - High transmissive glass and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass having high transmissivity suitable for construction, solar batteries and the like, and to provide a method for inexpensively manufac turing the glass capable of effectively prevention of NiS generation causing natural destruction. SOLUTION: The high transmissive glass comprises soda-lime silicate glass compositions containing 0.020-0.06 wt.% of all iron oxides converted as Fe2 O3 , 0-0.024 wt.% of FeO, 0-0.5 wt.% of cerium oxide, 0.001-1.0 wt.% of at least one oxide selected from yttrium oxide, lanthanum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, tungsten oxide, zinc oxide, garium oxide, germanium oxide, and tin oxide and less than 40 wt.% of iron oxides converted as Fe2 O3 in all iron oxides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soda lime silicate-based highly transparent glass produced mainly by a float method and a method for producing a highly transparent glass, and particularly nickel sulfide (NiS) when melting glass raw materials. TECHNICAL FIELD The present invention relates to a high-transmission glass and a method for producing a high-transmission glass, which can effectively suppress the formation of slag in molten glass.

[0002]

2. Description of the Related Art In a method for producing a soda-lime silicate glass plate by a float method, a roll-out method or the like, nickel (Ni) mixed in the glass raw material is mixed in the glass raw material in the process of melting the glass raw material at a high temperature of about 1500 ° C. in a melting kiln. ) -Containing stainless steel or other metal particles react with the sulfur (S) component in sodium sulfate (Na ₂ SO ₄ ) used as a glass raw material to produce nickel sulfide (N) in the melt-formed glass product.
iS) may exist as a minute foreign substance. NiS
Is very small, about 1 in every 10 tons of glass products, and is spherical and has a very small particle size of about 0.3 mm or less, so it is difficult to detect it on the production line.

By the way, a soda lime silicate type glass plate is subjected to a strengthening treatment and is used as a building glass, an automobile glass, a cover glass for a solar cell panel, a material for a solar water heater, etc. When applying, the glass plate is heated to near the softening point (about 600 ° C.) and then rapidly cooled to generate compressive stress in the surface layer of the glass plate.

When the tempered glass contains NiS,
This NiS exists as a stable α phase at a high temperature of about 350 ° C. or higher, and changes over time to a β phase that is stable at room temperature. This phase transition causes the volume of NiS to expand, resulting in cracks in the glass around the NiS. In the tempered glass, a strong tensile stress layer exists in the inner portion of the glass plate in the thickness direction of about 2/3. Therefore, when a crack is generated in the tensile stress layer, the crack rapidly propagates to cause natural damage to the tempered glass. .

In order to prevent such natural breakage of the tempered glass, the tempered glass is burned again (soak furnace).
By inserting it into a glass and heating it to a temperature of 300 ° C or lower and holding it for a certain period of time, causing NiS to undergo a phase transition from α phase to β phase, forcibly breaking the tempered glass and removing defective products containing NiS. A method (so-called soak processing) is known.

However, carrying out process work centering on heat treatment such as soak processing consumes a lot of energy and time, which increases the manufacturing cost and is a major obstacle to shortening delivery time and improving productivity. Becomes In addition, removal of defective products in the soak process lowers the product yield.

In Japanese Unexamined Patent Publication (Kokai) No. 9-169537, soda lime which suppresses the formation of NiS by adding 0.01 to 0.15% by weight of a zinc compound such as zinc nitrate and zinc sulfate to a glass raw material is disclosed. A method for producing silicate glass is disclosed.

On the other hand, interior glass, product display glass, exhibit protection case glass, highly transparent uncolored window glass, highly transparent uncolored mirror, solar cell panel base glass plate, solar cell panel cover glass, solar heat utilization As a flat display substrate glass for materials for water heaters, solar-transparent window glass materials, full-scale panels, etc., high-transmission glass, that is, a solar panel with a 3.2 mm thickness has a solar radiation transmittance of 87.5%.
The demand for glass having the above or visible light transmittance of 90.0% or more is increasing.

[0009]

However, when the present inventors confirmed the effect of the above-mentioned publication on the soda lime silicate-based high-permeability glass, it was found that the effect of suppressing NiS formation was not sufficient.

The present invention is a highly transparent glass capable of effectively suppressing the generation of NiS during the melting of glass raw materials in the production of soda lime silicate glass plates,
That is, the solar radiation transmittance of a glass plate having a thickness of 3.2 mm is 8
It is an object to provide a glass having 7.5% or more or visible light transmittance of 90.0% or more. Furthermore, it aims at providing the manufacturing method of highly transparent glass.

[0011]

That is, according to the present invention,
e ₂ O ₃ total iron oxide 0.020 to 0.06% by weight, FeO 0 to 0.024% by weight, cerium oxide 0
~ 0.5 wt% and at least one selected from the group consisting of yttrium oxide, lanthanum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, tungsten oxide, zinc oxide, gallium oxide, germanium oxide and tin oxide. Oxide 0.001
Fe containing 1.0% by weight and converted to Fe ₂ O ₃
The ratio of O in the total iron oxide (FeO ratio) is 40% by weight.
It is a highly transparent glass composed of a soda-lime silicate-based glass composition of less than 1.

The soda lime silicate glass composition constituting the high transmission glass of the present invention is yttrium oxide, lanthanum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, tungsten oxide, zinc oxide, gallium oxide, It contains at least one oxide selected from the group consisting of germanium oxide and tin oxide (hereinafter referred to as "heavy element oxide"). The heavy element oxide is an oxide that does not color the glass and does not cause a change that adversely affects the glass even when exposed to a reducing atmosphere in a float bath, for example. By including it in the material, it is possible to effectively suppress the generation of NiS that causes natural damage. It is presumed that the reason is that the heavy element in the heavy element oxide, which is present in a larger amount than nickel (Ni), combines with sulfur (S) to form a sulfide, making it difficult for Ni to combine with S. It

The contents of these heavy element oxides (the total amount when two or more kinds are used in combination) are Y ₂ O ₃ and La ₂ respectively.
O ₃ , ZrO ₂ , HfO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , WO ₃ ,
Converted to ZnO, Ga ₂ O ₃ , GeO ₂ and SnO ₂ ,
It is 0.001 to 1.0% by weight. If it is less than 0.001% by weight, the effect of preventing the generation of NiS becomes weak, and 1.0
If the content is more than wt%, the cost of the glass raw material becomes too high, and the glass tends to devitrify. A more preferable addition amount is 0.01 to 0.1% by weight, and a further preferable amount is 0.01 to 0.05% by weight. Further, the heavy element oxide has the same effect as the effect of preventing the generation of NiS, but lanthanum oxide, zirconium oxide, tantalum oxide, tungsten oxide, zinc oxide and tin oxide are preferably used because of the effect and cost. And zinc oxide is most preferably used. Further, as the raw material of these heavy element oxides, in addition to the oxides themselves, compounds such as sulfates, nitrates and carbonates which become oxides after the glass melting process can be used.

The soda-lime silicate glass composition of the present invention contains 0.02% of total iron oxide converted to Fe ₂ O _3.
0 to 0.06 wt% and FeO 0 to 0.0
The ratio of FeO contained in 24 wt% and converted to Fe ₂ O ₃ in the total iron oxide (FeO ratio) is less than 40 wt%.

Iron oxide is Fe in glass₂O₃And the state of FeO
Exist in a state. Fe₂O₃Is a component that enhances UV absorption
Yes, FeO is a component that enhances the heat ray absorption ability. Desired
In order to obtain a light color tone and high transmittance, the total iron content, mainly
Iron content Fe₂O₃And Fe₂O₃Is the total of FeO converted to
Total iron oxide (T-Fe₂O₃) Content is 0.06% by weight
Below, and FeO content 0-0.024 wt
%, And Fe ₂O₃FeO total iron oxide converted to
Must be less than 40% (FeO ratio).
It is important. If the total iron oxide content is less than 0.02%,
It is necessary to use high-purity raw material with low iron content as
The cost will rise significantly. Moreover, the FeO ratio is not 40% by weight.
By filling up, NiS formation by addition of heavy element oxides
Suppression is effectively performed. If the FeO ratio is 40% by weight
In the above case, sulfur (S) is S ^2-Easy to exist in the form of
NiS formation proceeds, but the FeO ratio is less than 40% by weight.
Sulfur (S) becomes S^2-Hard to exist in the form of
Therefore, it is estimated that NiS production is suppressed. FeO
If the ratio exceeds 40% by weight, the effect of suppressing NiS generation decreases.
In addition to reducing the visible light transmittance, FeO
It is not preferable because the blue color tone becomes strong. FeO included
If the content exceeds 0.024% by weight, the visible light transmittance is low.
As the color of the FeO becomes blue
Not preferable. FeO ratio is the oxidation added to the glass raw material
Of reducing agent and reducing agent, redox conditions of atmosphere in glass melting furnace
It can be controlled by adjusting

In order to obtain a lighter color tone, a higher visible light transmittance and a higher effect of suppressing NiS production, the total iron oxide content is in the range of 0.02 to 0.05% by weight and Fe
It is desirable that the O ratio is 30% or less. Higher N
In order to obtain the effect of suppressing iS generation, the FeO ratio is more preferably 20% or less. Thus, by suitably low T-Fe ₂ O ₃ and not extremely low FeO ratio, preferred high transmittance glass is obtained as architectural glass with the desired light color.

Further, for example, a glass for a solar cell (a substrate glass and a cover glass) using amorphous silicon has a high transmittance for light in a wavelength range of about 500 to 600 nm and a temperature rise of the amorphous silicon. It is desirable to appropriately absorb the solar radiation (especially heat rays) that causes a decrease in photoelectric conversion efficiency. In the case of such a glass, FeO is 0.004 to 0.024 in the above total iron oxide amount range.
40% by weight when the FeO ratio is 15% by weight or more.
It is desirable to be less than. FeO is 0.004 to 0.
It is more desirable that the FeO ratio is in the range of 012 wt% and the FeO ratio is in the range of 20 to 30 wt%. As described above, when used for a solar cell, not only has high transmittance in the wavelength region of high sensitivity, but also contains moderate FeO, which adversely affects the conversion efficiency and raises the temperature of amorphous silicon. It also has another preferable effect of appropriately absorbing the solar radiation that causes

On the other hand, in the case of a glass for a solar cell using crystalline silicon, which is desired to have a high transmittance for light having a wavelength of around 1000 nm, or a so-called white glass for construction with almost no coloring, the above total iron oxide is used. In the range of the amount, FeO is preferably 0 to 0.008% by weight, and the FeO ratio is preferably 0 to 20% by weight, and FeO is 0.
It is more desirable that the amount is 006% by weight or less. Thus, due to the moderately low T-Fe ₂ O ₃ and FeO ratio, it is made of crystalline silicon with almost no coloring, particularly as so-called white plate glass which is desirable for building materials, and has the highest energy conversion sensitivity around 1000 nm. It is suitable as glass for solar cells.

Cerium oxide is not an essential component, but is a component effective as an oxidizing agent for adjusting the ratio of FeO and FeO, and its content is 0 to 0.5% by weight in terms of CeO _2. . In order to achieve a low FeO, FeO ratio necessary for obtaining a glass having almost no coloration or a high transmittance particularly for light having a wavelength of about 1000 nm, the cerium oxide content is 0.025 to
It is preferably 0.5% by weight, and 0.025-0.
25% by weight is more preferred. Since cerium oxide also has an effect of absorbing ultraviolet light, another preferable effect of moderately absorbing ultraviolet rays, which has an undesirable effect in various applications such as deterioration of silicon when used as glass for solar cells, can be obtained. .

In manufacturing the high transmission glass according to the present invention
To reduce the cost of glass as much as possible
In addition, as a raw material, the same as for soda-lime glass,
It is possible to use silica sand containing aluminate, limestone, and alumina.
Desirably, this is T-Fe ₂O₃Content in the above range
It becomes possible by

As the melting method, in order to reduce the cost increase of glass as much as the above, the batch raw material is used in a normal soda lime type glass melting furnace, and the kiln tank has one liquefying stage and one refining stage. It is desirable to melt in an upper heating tank type melting furnace carried out in-house.

The soda lime silicate type glass composition constituting the high transmission glass of the present invention is the above-mentioned total iron oxide, Fe.
In addition to the components of O, cerium oxide and heavy element oxide, it is preferable to contain the following components as a basic glass composition. That is, the basic glass composition is expressed in% by weight,
65% to 80% of SiO _2, 0 to 5% of the Al ₂ O _3, 2~7
% MgO, 5-15% CaO, but MgO + Ca
O is 5 to 15%, 10 to 18% Na ₂ O, 0 to 5% K ₂ O, but Na ₂ O + K ₂ O is 10 to 20%, 0.0
It contains 5 to 0.3% SO ₃ , and 0 to 5% B ₂ O ₃ .

The reasons for limiting the basic glass composition will be described below with respect to components other than total iron oxide, FeO, cerium oxide and heavy element oxides. However, the following compositions are expressed in% by weight.

SiO ₂ is the main component forming the skeleton of glass. If the SiO ₂ content is less than 65%, the durability of the glass will be reduced, and if it exceeds 80%, it will be difficult to melt the glass.

Al ₂ O ₃ is a component for improving the durability of glass, but if it exceeds 5%, melting of glass becomes difficult. It is preferably in the range of 0.1 to 2.5%.

MgO and CaO are used to improve the durability of glass and to adjust the devitrification temperature and viscosity during molding. If MgO is less than 2%, the devitrification temperature rises. When CaO is less than 5% or exceeds 15%, the devitrification temperature increases. If the total amount of MgO and CaO is less than 5%, the durability of the glass will decrease, and if it exceeds 15%, the devitrification temperature will increase. When the total amount of MgO and CaO is small, for example, less than 10%, it is necessary to add a large amount of Na ₂ O to compensate for the deterioration of the solubility and the increase of the viscosity of the glass melt. Since it causes deterioration of durability, Mg
The total of O and CaO is preferably 10% or more.

Na ₂ O and K ₂ O are used as glass melting accelerators. When Na ₂ O is less than 10% or the total amount of Na ₂ O and K ₂ O is less than 10%, the dissolution promoting effect is poor, and Na ₂ O exceeds 18%, or Na ₂ O and K ₂
If the total amount of O exceeds 20%, the durability of glass decreases. Since K ₂ O is expensive as a raw material compared to Na ₂ O, 5
% Is not preferable.

SO ₃ is a component that promotes the fining of glass. If it is less than 0.05%, the fining effect becomes insufficient by the usual melting method, and the desirable range is 0.1% or more. On the other hand, if it exceeds 0.3%, SO ₂ produced by its decomposition remains in the glass as bubbles, or bubbles tend to be generated by reboil.

B ₂ O ₃ is not an essential component, but it is a component used for improving the durability of glass or as a melting aid. If B ₂ O ₃ exceeds 5%, inconvenience during molding due to volatilization of B ₂ O _{3 or} the like occurs, so the upper limit is 5%.

Although TiO ₂ is not an essential component, it can be added in an appropriate amount for the purpose of increasing the ultraviolet absorbing ability, etc. within a range not impairing the optical characteristics aimed at by the present invention.
If the amount is too large, the glass tends to become yellowish,
Also, since the transmittance in the vicinity of 500 to 600 nm decreases,
It is desirable that the content be kept low within the range of less than 0.2%.

Further, even if fluorine, barium oxide or strontium oxide is contained, the effect of the present invention is not impaired, but these components have an unfavorable influence on cost increase, kiln life, release of harmful substances to the atmosphere, etc. Is an ingredient that exerts
It is desirable not to contain it substantially.

Se, CoO, Cr ₂ O ₃ , NiO, V ₂ O ₅ and MoO are usually added to the glass having the above composition range as a coloring agent in a range not impairing the light color tone of the present invention.
At least one kind of ₃ or the like may be added at the same time, but the addition of the colorant strengthens the color tone and lowers the visible light transmittance, so it is preferable not to add substantially.

The high transmission glass of the present invention is usually 0.3 mm.
It has a thickness of ~ 30mm, and it is used for interior glass, product display glass, exhibit protection case glass, highly transparent uncolored window glass, highly transparent uncolored mirror, solar cell panel substrate glass, and solar cell panel. Suitable for cover glass, solar water heater material, solar heat transparent window glass material, microwave oven window glass material or flat display substrate glass such as whole panel.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to specific examples.

[Example 1, Comparative Examples 1, 12 and 13]
Low iron alumina-containing silica sand, limestone, dolomite, soda ash, glauber's salt, cerium oxide, zirconium oxide, zinc sulphate so as to have the composition shown in Table 1 in terms of weight% And a carbon-based reducing agent were mixed to obtain the glasses of Example 1 and Comparative Examples 1, 12 and 13. The FeO content of these glasses is 1000 nm at a thickness of 5 mm.
It was calculated by calculating from the light transmittance of. In addition,
The composition indication in the table is% by weight.

[0036]

[Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 Comparative Example 1 Comparative Example 12 Comparative Example 13 -------- ------------------------------------------- SiO ₂ 71.7 71.7 71.7 73.1 Al ₂ O ₃ 1.68 1.68 1.68 1.80 MgO 4.4 4.4 4.4 0.08 CaO 8.8 8.8 8.8 10.1 SrO 0 0 0 0.21 Na ₂ O 12.5 12.5 12.5 14.6 K ₂ O 0.7 0.7 0.7 0.01 SO ₃ 0.15 0.15 0.15 0.015 Total iron oxide 0.036 0.036 0.036 0.010 TiO ₂ 0.04 0.04 0.04 0 Cerium oxide 0 0 0 0 ZrO ₂ 0 0 0 0.028 Total 100.006 100.006 100.006 99.953 FeO 0.010 0.010 0.022 0.006 FeO ratio (%) 31 31 60 60 ZnO 0.08 0 0.08 0 --------- ------------------------------------------- Visible light transmittance (%) 91.3 91.3 90.4 90.7 Solar transmittance (%) 89.5 89.5 87.0 90.3 Ultraviolet transmittance (%) 77.9 77.9 78.5 83.8 Principal wavelength (nm) 499 499 492 491 Excitation purity (%) 0.14 0.14 0.38 0.10 NiS number 4 30 20 25 ━━ ━━━━━━━━━━━━━━━━━━━━━━━━ ━

Next, this glass was polished to a thickness of 3.2 mm, and visible light transmittance, dominant wavelength, stimulus purity, solar radiation transmittance, I
The ultraviolet transmittance defined by SO9050 was measured. The optical characteristic values of the obtained sample are shown in Table 1.

Further, Example 1, Comparative Examples 1, 12 and 13
Average particle size of 149μm for 200g of glass compound
0.028 g of Ni particles was added. Put these glass raw materials in an alumina crucible with a capacity of 250 cm ² , and set at 600 ° C.
After being preheated for 30 minutes, the temperature was raised to 1400 ° C. in 10 minutes in an electric furnace maintained at 1370 ° C. Further, after holding at this temperature for 2.2 hours, the crucible was taken out of the furnace, cast and gradually cooled from 650 ° C. to room temperature.

With respect to the glass of Example 1 and Comparative Examples 1, 12 and 13 thus obtained, the number of NiS particles present in the glass was measured by a stereoscopic microscope to obtain glass 10
The number of NiS per 0 g was calculated. The results are shown in Table 1.
From the results of Table 1, Comparative Example 1 in which the FeO ratio is less than 40% by weight but does not contain the heavy element oxide, and Comparative Example 1 which contains the heavy element oxide but in which the FeO ratio exceeds 40% by weight.
As compared with Nos. 2 and 13, in Example 1 containing a heavy element oxide (zinc oxide) and having a FeO ratio of less than 40% by weight, it can be seen that the generation of NiS particles is effectively suppressed.

[Examples 2 to 11, Comparative Examples 2 to 11] Low iron alumina-containing silica so as to have the composition shown in Tables 2 and 3 in terms of weight% in terms of (base glass) oxide. Sand, limestone, dolomite, soda ash, glauber's salt, cerium oxide and a carbon-based reducing agent were mixed to obtain No. 1-10 base glass. The FeO content of these glasses was obtained by calculating from the transmittance of light having a wavelength of 1000 nm at a thickness of 5 mm. In addition, the composition indication in the table is% by weight.

Then, the glass was polished in the same manner as in Example 1 and the optical characteristics were measured. The optical characteristic values of the obtained sample are shown in Tables 2 and 3. In addition, when the optical characteristics of the base glass to which each heavy element oxide was added as shown in Table 4 in place of the No. 1 to 10 base glass were measured,
The optical characteristic values were almost the same as those of the base glasses of Nos. 1 to 10 in which the heavy element oxides were not added.

Further, the compounding raw material 20 of these glass Nos. 1 to 10
Ni particles with an average particle size of 149 μm for 0 g 0.028
g was added and further converted into oxides and expressed in% by weight, as shown in Table 4, each of the heavy element oxides was added to Examples 2 to 11, and those without the heavy element oxides were added. It was set as Comparative Examples 2-11. These glass raw materials were subjected to crucible melting and casting, slow cooling, and NiS particle number measurement in the same manner as in Example 1, and Table 4 shows the calculation results of the NiS number.

From the results of Table 4, by adding the heavy element oxide and setting the FeO ratio to less than 40% by weight, the Ni
It can be seen that the generation of S is suppressed.

[0044]

[Table 2] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ No. 1 No. 2 No. 3 No. 4 No. 5 -------------------------------------------------- ----------- SiO ₂ 72.2 71.2 72.2 71.7 71.0 Al ₂ O ₃ 1.66 1.75 1.66 1.66 1.42 MgO 4.2 4.2 4.2 4.4 4.3 CaO 8.5 8.5 8.5 8.8 8.6 Na ₂ O 12.5 13.1 12.5 12.5 13.5 K ₂ O 0.7 1.0 0.7 0.7 0.7 SO ₃ 0.20 0.18 0.20 0.15 0.22 Total iron oxide 0.025 0.036 0.045 0.055 0.031 TiO ₂ 0.02 0.04 0.02 0.04 0.03 Cerium oxide 0 0 0 0 0.2 Total 100.005 100.006 100.025 100.005 100.001 FeO 0.005 0.008 0.009 0.019 0.003 FeO ratio (% ) 22 25 22 38 11 -------------------------------------------- ----------------- Visible light transmittance (%) 91.5 91.3 91.3 91.1 91.6 Solar radiation transmittance (%) 90.7 89.9 89.5 88.5 90.9 UV transmittance (%) 79.7 76.9 75.0 73.5 42.9 Principal wavelength (nm) 547 513 525 530 563 Stimulation purity (%) 0.10 0.08 0.15 0.17 0.20 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ━━━━━━

[0045]

[Table 3] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ No. 6 No. 7 No. 8 No. 9 No. 10 -------------------------------------------------- ------------ SiO ₂ 71.7 71.6 72.0 71.1 71.3 Al ₂ O ₃ 1.69 1.68 1.77 1.82 1.50 MgO 4.0 4.2 4.2 4.4 4.2 CaO 8.5 8.5 8.5 9.0 8.5 Na ₂ O 13.0 13.0 12.5 12.6 13.1 K ₂ O 0.7 0.7 0.7 0.7 1.0 SO ₃ 0.25 0.20 0.21 0.23 0.23 Total iron oxide 0.031 0.036 0.036 0.036 0.036 TiO ₂ 0.03 0.04 0.04 0.04 0.04 Cerium oxide 0.1 0.05 0.05 0.075 0.1 Total 100.001 100.006 100.006 100.001 100.006 FeO 0.001 0.007 0.005 0.003 0.003 FeO ratio 4 22 15 9 9 ---------------------------------------------- ---------------- Visible light transmittance (%) 91.8 91.4 91.7 91.6 91.6 Solar radiation transmittance (%) 91.6 89.9 91.0 91.0 91.0 UV transmittance (%) 50.3 55.4 54.9 51.5 48.4 Main wavelength (nm) 568 547 562 566 566 Stimulation purity (%) 0.23 0.10 0.23 0.26 0.26 ━━━━━━━━━━━━━━━━━━━━━━━ ━━━━━━━━━

[0046]

[Table 4] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example No. 2 3 4 5 6 7 8 9 10 11 ----------------------------------------------- ------------------------ Beacon number 1 2 3 4 5 6 7 8 9 10 Heavy element oxide ZnO * ZnO ** Y ₂ O ₃ La ₂ O ₃ ZrO ₂ HfO ₂ Ta ₂ O ₅ Nb ₂ O ₅ WO ₃ Ga ₂ O ₃ Content (wt%) 0.04 0.1 0.05 0.1 0.05 0.05 0.05 0.05 0.05 0.05 ------------ -------------------------------------------------- --------- Number of NiS particles 9 1 5 3 3 2 4 2 1 3 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Comparative example number 2 3 4 5 6 7 8 9 10 11 ------------------------------------------- --------------------------- Beasulas number 1 2 3 4 5 6 7 8 9 10 ---------- -------------------------------- ---------------------------- Number of NiS particles 32 24 16 17 21 19 20 18 16 17 ━━━━━━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━ *: Use zinc nitrate hexahydrate as a raw material **: Use zinc sulfate as a raw material

[0047]

As described in detail above, according to the present invention, it is possible to effectively suppress the generation of NiS which causes little damage or is very light in color and has a high transmittance and which causes spontaneous damage. Highly transparent glass can be obtained at low cost.

The addition of the heavy element oxide not only hardly changes the visible light transmittance and the ultraviolet transmittance, but also does not change the physical properties of the glass such as the coloring property, the viscosity, and the expansion, and the transmittance is particularly high. It is possible to maintain the quality as before while maintaining the above, so that there are great practical advantages.

Further, according to the present invention, it becomes possible to manufacture a glass product containing almost no NiS, and a heat treatment (soak treatment) step for removing the glass containing NiS after the quenching and tempering treatment is also possible in the tempered glass manufacturing process. Since it is unnecessary, it is possible to reduce the manufacturing cost. Further, the glass breakage rate in the soak process is reduced, and the product yield can be improved.

The highly transparent glass of the present invention is useful as architectural glass, and also useful as glass for solar cells, which requires high solar transmittance.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G062 AA01 BB03 DA06 DA07 DB01                       DB02 DB03 DC01 DC02 DC03                       DD01 DE01 DE02 DF01 EA01                       EB04 EC01 EC02 EC03 ED03                       EE03 EE04 EF01 EG01 FA01                       FA10 FB01 FB02 FC01 FC02                       FD01 FD02 FE01 FE02 FF01                       FG01 FG02 FH01 FH02 FJ01                       FJ02 FK01 FK02 FL01 GA01                       GB02 GC01 GD01 GE01 HH01                       HH03 HH05 HH06 HH07 HH08                       HH09 HH12 HH13 HH15 HH17                       HH18 JJ01 JJ03 JJ05 JJ07                       JJ10 KK01 KK03 KK05 KK07                       KK10 NN01

Claims (14)

[Claims] 1. Total iron oxide 0.020 converted to Fe ₂ O _3.
-0.06 wt%, FeO 0-0.024 wt%, cerium oxide 0-0.5 wt%, and yttrium oxide, lanthanum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, tungsten oxide, zinc oxide At least one oxide selected from the group consisting of, gallium oxide, germanium oxide and tin oxide
FeO in 0.001 to 1.0% by weight and converted to Fe ₂ O ₃ in the total iron oxide (FeO ratio)
Highly transparent glass comprising a soda-lime silicate-based glass composition having a content of less than 40% by weight. 2. The FeO content is 0.004 to 0.0.
40% by weight when the FeO ratio is 15% or more and 24% by weight.
The high transmission glass according to claim 1, which is less than wt%. 3. The FeO content is 0.004 to 0.0.
The high transmission glass according to claim 1, which is 12% by weight and the FeO ratio is 20 to 30%. 4. The FeO content is 0 to 0.008% by weight, and the cerium oxide content is 0.025 to 0.
The high transmission glass according to claim 1, which is 5% by weight and the FeO ratio is 0 to 20%. 5. The FeO content is 0 to 0.006 wt%, and the cerium oxide content is 0.025 to 0.
The high transmission glass according to claim 1, which is 25% by weight and the FeO ratio is 0 to 20%. 6. The high transmission glass according to claim 1, wherein the oxide content is 0.01 to 0.1% by weight. 7. The method according to claim 1, wherein the oxide is zinc oxide.
The high transmission glass according to any one of 6 above. 8. The glass composition, expressed in wt%, is 65-80% SiO ₂ , 0-5% Al ₂ O ₃ , 2
~ 7% MgO, 5-15% CaO, but MgO +
CaO is 5-15%, 10-18% Na ₂ O, 0-5
% K ₂ O, but Na ₂ O + K ₂ O is 10-20%,
0.05-0.3% SO ₃ , and 0-5% B
The high transmission glass according to any one of claims 1 to 7, which contains ₂ O ₃ . 9. The MgO + CaO content is 10-15.
Percent by weight, and the SO ₃ content from 0.1 to 0.
The high transmission glass according to claim 8, which is 3% by weight. 10. The method for producing a highly transparent glass according to claim 1, wherein at least dolomite or limestone is used as a raw material for the glass. Method. 11. The method for producing a highly transparent glass according to claim 1, wherein at least alumina-containing silica sand is used as a raw material for the glass. Method. 12. The method for producing highly transparent glass according to claim 10, wherein the glass raw material is melted in an upper heating tank type melting furnace. 13. A method for producing soda-lime glass, which suppresses the formation of nickel sulfide particles in melt-formed glass by adding a zinc compound to a glass raw material, comprising total iron oxide (Fe ₂ O ₃₎ in the glass. (Conversion) content is 0.
020 to 0.05% by weight, zinc oxide content 0.001 to 1.0% by weight, and the ratio of FeO to total iron oxide (FeO ratio) converted to Fe ₂ O ₃ is less than 40% by weight. The glass is a soda having a high transmittance of 87.5% or more of solar radiation transmittance or 90.0% or more of visible light transmittance in a glass plate having a thickness of 3.2 mm. Method for producing lime silicate glass. 14. The manufacturing method according to claim 10, including a step of performing a quenching strengthening treatment.