JPH09295829A - Ultraviolet light absorbing green glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glass of green color tone high in visible light transmittance and low in ultraviolet light transmittance, substantially comprising a specific soda lime silica glass and making the glass have specific light transmittances. SOLUTION: This glass substantially comprises a sodium lime silica glass having a composition of 0.45-<0.52wt.% shown by Fe2 O3 of total iron, 0.8-2wt.% shown by CeO2 of total cerium, 0.2-0.6wt.% of TiO2 , 0-0.002wt.% of CoO in the weight ratio of bivalent iron calculated as Fe2 O3 in the total iron of 25-35wt.%, preferably further 65-75wt.% of SiO2 , 0.1-5wt.% of Al2 O3 , 10-18wt.% of N2 O+K2 O, 5-15wt.% of CaO, 1-6wt.% of MgO and 0.05-1wt.% of SO3 . The glass has 4.5-7.0mm thickness, >=70% visible light transmittance by a light source of standard A, <=15% ultraviolet light transmittance and <=30% light transmittance at a light of 370nm wavelength.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet absorbing green glass having a small solar radiation transmittance.

[0002]

2. Description of the Related Art Solar transmittance (see JIS R3106)
And Fe converted into Fe ₂ O ₃ as glass for vehicles with extremely reduced ultraviolet transmittance (see ISO 9050)
A soda lime silica-based glass in which the weight of O is 45% or more of the weight of total iron converted to Fe ₂ O ₃ is known (Japanese Patent Laid-Open No. 64-18938). This glass has a blue hue.

This glass contains Fe converted to Fe ₂ O _3.
Since the weight of O is 45% or more of the weight of total iron converted to Fe ₂ O ₃ , the clarification agent Glauber's salt does not substantially perform the clarification action. Therefore, it is necessary to hold the molten glass under reduced pressure to degas, and there is a problem that the glass melting process is complicated.

Further, it has a green color tone, and Fe ₂ O ₃
JP-A-3-187946 discloses a soda lime silica glass containing 0.51% by weight or more.

That is, with a thickness of 3 mm, total iron: 0.68-0.
92% (wt%, hereinafter the same for the glass composition),
_{CeO 2: 0.5~1.2%, TiO 2} : 0.02~
Amount of divalent iron in total iron containing 0.85% 23-29
%. In addition, 4 mm thick total iron: 0.61 to 0.86
%, CeO ₂ : 0.3 to 0.75%, TiO ₂ : 0.0
2 to 0.45%, and the amount of divalent iron in the total iron is 23 to
29%.

Japanese Patent Laid-Open No. 3-56466 discloses a glass having a reduced solar radiation transmittance and an ultraviolet transmittance, which is a total glass of Fe ₂ O ₃ converted to Fe ₂ O ₃ in a mother glass of soda lime silica: 0.53 to 0. _{.70%, Fe 2 O 3:} 0.35~
0.50%, FeO: 0.16-0.24%, TiO
₂ 0.2 to 0.4% total of cerium in terms of CeO _2: containing 0.5 to 0.8%, and the weight of FeO which in terms of Fe ₂ O ₃ is converted to Fe ₂ O ₃ A glass is disclosed that is 30-40% of the weight of the total iron produced.

Further, in US Pat. No. 2860059, Fe ₂ O ₃ : 0.20 to 0.60%, TiO ₂ :
0.19 to 1.90%, CeO ₂ : 0.05 to 0.50
A colorless UV-absorbing glass containing 100% is disclosed.

However, there is a problem that such a glass is not sufficiently satisfactory in the ultraviolet absorbing performance.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above problems of the prior art and has a visible light transmittance of 70% or more, a small solar radiation transmittance, and an ultraviolet transmittance, particularly a transmittance of a wavelength of 370 nm. It is an object of the present invention to provide an ultraviolet absorbing green glass having a smaller value.

[0010]

SUMMARY OF THE INVENTION The present invention is based on F% by weight.
e ₂ O ₃ total iron expressed as 0.45 to less than 0.52%, C
Total cerium expressed in eO ₂ : 0.8 to ₂ %, TiO ₂ :
0.2 to 0.6% CoO: containing from 0 to 0.002%, by weight percentage of divalent iron in terms of Fe ₂ O ₃ in the total iron in terms of Fe ₂ O ₃ is 25-38 Substantially consists of soda-lime silica glass, which is 4.5% to 4.5-7.0 mm
, The visible light transmittance by the standard A light source is 70% or more, the ultraviolet transmittance is 15% or less, and the wavelength is 370.
It is an ultraviolet absorbing green glass having a light transmittance of 30% or less in nm.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The above components will be described below. If the total iron content represented by Fe ₂ O ₃ is less than 0.45%, the solar radiation transmittance and the ultraviolet transmittance become too large, and if it is 0.52% or more, the visible light transmittance becomes too small. Preferably, it is 0.48 to 0.51%. If the amount of divalent iron in this total iron is less than 25%, the solar radiation transmittance becomes too high, and if it exceeds 38%, the melting process of glass becomes complicated and the tone of blue becomes a desired green color. I can't get the glass with the color tone. It is preferably 27 to 33%.

When the content of total cerium represented by CeO ₂ is less than 0.8%, the ultraviolet transmittance, particularly the transmittance at a wavelength of 370 nm, which has a bad effect on the human body, becomes too large, and when it is more than 2%, the color becomes yellow. It becomes a color tone, and glass having a green color tone and a high visible light transmittance cannot be obtained, and the raw material cost becomes high. In addition, it takes a long time to change the type of glass at the time of glass production, which lowers the productivity. Preferably,
It is 0.8 to 1.2%.

When the content of TiO ₂ is less than 0.2%, the ultraviolet light transmittance becomes too large, and when it is more than 0.6%, the visible light transmittance becomes too small and a yellow color tone is obtained. I can't get a glass with a green hue. It is preferably 0.3 to 0.5%.

Although CoO is not an essential component, a small amount of CoO makes it possible to adjust the color tone of yellowish glass with CeO ₂ , TiO ₂ or the like to the desired green color tone. Preferably, 0.0002% or more is contained.
On the other hand, if it exceeds 0.002%, the visible light transmittance becomes too small.

As the ultraviolet absorbing green glass of the present invention, those having substantially the following composition in weight% are preferable. _{SiO 2: 65~75%, Al 2} O 3: 0.1~5%, Na 2 O + K 2 O: 10~18%, CaO: 5~15%, MgO: 1~6%, SO 3: 0. 05 to 1%, total iron expressed by Fe ₂ O ₃ : 0.45 to less than 0.52%, total cerium expressed by CeO ₂ : 0.8 to ₂ %, TiO ₂ : 0.2 to 0.6 %, CoO: 0 to 0.002%.

When the content of SiO ₂ is less than 65%, the weather resistance is lowered, and when it exceeds 75%, devitrification is likely to occur. A
If the content of l ₂ O ₃ is less than 0.1%, the water resistance will decrease, and if it exceeds 5%, the solubility will decrease.

Na ₂ O and K ₂ O are components that promote the melting of the raw materials. If the total content is less than 10%, the effect is small, and if it is more than 18%, the weather resistance is deteriorated.

CaO and MgO accelerate the dissolution of the raw materials,
It is a component that improves weather resistance. If the content of CaO is less than 5%, the above effect is small, and if it is more than 15%, devitrification is likely to occur. If the content of MgO is less than 1%, the above effect is small, and if it is more than 6%, devitrification tends to occur.

SO ₃ is used as a fining agent and usually remains in the glass in an amount of about 0.05 to 1%.

Furthermore, in the present invention, it is preferable to adjust the specific gravity of the glass to about 2.49 to 2.53. More preferably, it is 2.51 to 2.52. By making the specific gravity of the soda lime silica glass to be the same as that of ordinary soda lime silica glass, the efficiency of composition change during manufacturing can be improved.

The specific gravity can be adjusted by adjusting the composition of the mother glass. Specifically, the weight ratio SiO ₂ / (M
gO + CaO) to 5.0 to 7.0, more preferably
The specific gravity can be adjusted by setting it to 5.4 to 6.6. This weight ratio is more preferably 6.0 to 6.6.
It is.

From this viewpoint, the weight ratio CaO / Mg is
O is preferably 1.3 to 2.5, more preferably 1.
Set to 5-2.3.

The UV absorbing glass according to the present invention is usually
It is used in the range of 4.5 to 7.0 mm. Also, in the thickness used, visible light transmittance (standard A light source) 70%
As described above, the ultraviolet transmittance is 15% or less, particularly 10% or less, and the transmittance at a wavelength of 370 nm is 30% or less.

The dominant wavelength of the light transmitted by the standard C light source is preferably 515 to 535 nm, and the solar radiation transmittance is 35 to 50%, particularly 40 at the thickness used.
It is preferably about 45%. In addition, it is preferable that it has characteristics of an ultraviolet transmittance of 10% or less and a stimulation purity of 3% or less, especially 2 to 3% in terms of 5 mm thickness.

The ultraviolet absorbing glass of the present invention can be used for both construction and vehicles, but it has a large visible light transmittance and is therefore suitable as a window glass for automobiles. When used as window glass for automobiles, tempered glass is used as the window glass for the side and rear. Further, when used as a double glazing for construction, it can be used as a double glazing of two glass of the present invention or a double glazing of the glass of the present invention and another glass.

The ultraviolet absorbing glass of the present invention can be manufactured, for example, as follows. That is, each raw material is prepared so as to have a target glass composition. The raw materials used at that time are FeO, Fe ₂ O ₃ source, iron powder,
Bengal and the like include cerium oxide, cerium carbonate, cerium hydroxide and the like as cerium sources, and titanium oxide and the like as titanium sources. As a raw material for the mother glass, a commonly used one is used. Furthermore, by adding a reducing agent such as carbon to these raw materials, the iron in the molten glass becomes Fe ₂ O ₃
It is preferable that FeO be contained in a predetermined amount in order to prevent the oxidation of FeO.

The raw material thus prepared is continuously supplied to a melting furnace and heated to about 1500 ° C. with heavy oil or the like to melt and vitrify. Then, after the molten glass is clarified, it is formed into a plate glass having a predetermined thickness by a float method or the like. Next, the ultraviolet absorbing glass of the present invention is manufactured by cutting this plate glass into a predetermined shape. Thereafter, if necessary, the cut glass can be subjected to a tempering treatment, processed into a laminated glass, or processed into a multilayer glass.

[0028]

Examples SiO ₂ : 72 parts (parts by weight, the same applies hereinafter), A
l ₂ O ₃ : 1.7 parts, Na ₂ O: 12.3 parts, K ₂ O:
0.5 part, CaO: 7.8 part, MgO: 3.9 part and S
O ₃ : Total iron expressed by Fe ₂ O ₃ as an optical property improving component in a mother composition of 0.6 parts (abbreviated as tFe ₂ O _{3 in} Table 1, unit: wt%), CeO ₂ (unit: weight) %), T
A soda lime silica glass containing iO ₂ (unit: wt%) and CoO (unit: wt%) in the amounts shown in the upper part of Table 1 was produced. Fe ₂ O ₃ in total iron converted to Fe ₂ O ₃
The ratio of divalent iron converted to (in Table 1, abbreviated as REDOX, unit:%) is also shown in the same column. In the examples, the weight ratio SiO ₂ / (MgO + CaO) is 6.15 and the weight ratio CaO / MgO is 2.0.

In producing glass, raw materials prepared in advance were put in a crucible and heated in an electric furnace to melt and vitrify. Then, the molten glass was poured onto a stainless steel plate and both surfaces were polished to obtain a plate glass having a thickness of 6.0 mm.

With respect to this plate glass, the solar radiation transmittance T _E
(Unit:%), visible light transmittance (by standard A light source)
T _Va (unit:%), ultraviolet transmittance T _uv (unit:%), light transmittance T ₃₇₀ (unit:%) at wavelength 370 nm, main wavelength D _W (unit: nm) by standard C light source, stimulation purity P _The results of determining _e (unit:%) and specific gravity are shown in the lower part of Table 1. The stimulation purity P _e is a value converted into a thickness of 5.0 mm.

The solar radiation transmittance and the visible light transmittance are JI.
UV transmittance according to S R3106 is ISO 905
0, the dominant wavelength and the excitation purity were determined according to JIS Z8722, respectively.

As is clear from Table 1, the glass of the present invention has a green color tone, a large visible light transmittance, a small solar radiation transmittance, and a particularly small ultraviolet transmittance.

[0033]

[Table 1]

[0034]

According to the present invention, there is provided a glass having a green color tone, which has a large visible light transmittance and a small ultraviolet transmittance, particularly, a transmittance at a wavelength of 370 nm. Such glass is particularly suitable as a window glass for automobiles.

Claims (5)

[Claims] 1. Total iron expressed in Fe ₂ O ₃ in% by weight: 0.
Less than 45 to 0.52%, the total cerium in terms of CeO _{2:
0.8~2%, TiO 2: 0.2~0.6%} , CoO:
Containing 0~0.002%, Fe ₂ O ₃ weight ratio of divalent iron in terms of Fe ₂ O ₃ in the total iron in terms of the 25
It consists essentially of 38% soda lime silica glass, has a thickness of 4.5-7.0 mm, a visible light transmittance of 70% or more by a standard A light source, and an ultraviolet transmittance of 15%.
UV absorbing green glass having a light transmittance of 30% or less at a wavelength of 370 nm. 2. The ultraviolet-absorbing green glass according to claim 1, which is substantially composed of the following composition in a substantial weight percentage. _{SiO 2: 65~75%, Al 2} O 3: 0.1~5%, Na 2 O + K 2 O: 10~18%, CaO: 5~15%, MgO: 1~6%, SO 3: 0. 05 to 1%, total iron expressed by Fe ₂ O ₃ : 0.45 to less than 0.52%, total cerium expressed by CeO ₂ : 0.8 to ₂ %, TiO ₂ : 0.2 to 0.6 %, CoO: 0 to 0.002%. 3. The dominant wavelength of transmitted light from a standard C light source is 515.
The ultraviolet absorbing green glass according to claim 1 or 2, having a wavelength of ˜535 nm. 4. The ultraviolet absorbing green glass according to claim 1, 2 or 3, which has a stimulus purity of 3% or less when converted to a thickness of 5 mm by a standard C light source. 5. The ultraviolet absorbing green glass according to claim 1, 2, 3 or 4, which has a specific gravity of 2.49 to 2.53.