JPH08245238A - Low transmission glass - Google Patents

Abstract

PURPOSE: To obtain a low transmission glass not essentially contg. harmful volatile Se or Ni liable to form nickel sulfide as a coloring component. CONSTITUTION: This low transmission glass consists of a basic glass compsn. and coloring components. The basic glass compsn. consists of, by weight, 65-80% SiO2 , 0-5% Al2 O3 , 0-5% B2 O3 , 5-15%, in total, of 0-10% MgO and 5-15% CaO, and 10-20%, in total, of 10-18% Na2 O and 0-5% K2 O. The coloring components are 0.95-2.20% (expressed in terms of Fe2 O3 ) total iron oxide (the ratio of FeO to total iron oxide is 0.13-0.30) 0.9-2.3% TiO2 , 0.010-0.020% CoO and 0-1.0% CeO2 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a greenish color tone,
Further, the present invention relates to a low-transmittance glass which has low visible light transmittance, sunlight transmittance, and ultraviolet light transmittance, and is particularly useful as a glass for skylights of vehicles, a glass for protecting privacy, and the like.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of prevention of deterioration of interior materials due to upsizing of interior materials for automobiles, cooling load and reduction of greenhouse effect, various types of window glass for automobiles are provided with ultraviolet and infrared absorbing ability. Glass has been proposed. Further, as the color tone of glass, green type tends to be preferred over conventional blue type and neutral gray type.

For example, the ultraviolet / infrared absorbing glass having a greenish color tone disclosed in Japanese Patent Laid-Open No. 187946/1993 is 65 to 75% SiO ₂ and 0 to 3% Al expressed as a weight percentage as a mother composition. ₂ O ₃ , 1-5% MgO, 5
15% of CaO, 10 to 15% of Na ₂ O, and 0
0.5% as a coloring component in a glass containing 4% K ₂ O.
In 1 to 0.96%, and FeO / T-Fe ₂ O ₃ ratio (total iron oxide in terms Fe ₂ O ₃ and T-Fe ₂ O ₃ in this case) is zero.
Total iron oxide ₃ in terms of Fe ₂ O of from 23 to 0.29, 0.2
˜1.4% CeO ₂ and 0 to 0.85 TiO ₂ are included.

The ultraviolet and infrared absorbing glass having a green color tone disclosed in JP-A-6-56466 is
Soda - lime - silica based mother glass composition, with 0.53 to 0.70% as a coloring component, and then in% by weight FeO / T-Fe ₂ O ₃ ratio is 0.30 to 0.40 Fe
Total iron oxide converted to ₂ O ₃ , 0.5 to 0.8% Ce
O ₂ and 0.2 to 0.4 of TiO ₂ are contained.

Further, the ultraviolet and infrared absorbing glass having a greenish color tone disclosed in JP-A-6-191880 has a soda-lime-silica based mother glass composition of 0.75% or more as a coloring component, Also, Fe ₂ having a FeO / T-Fe ₂ O ₃ ratio of 0.22 to 0.29 expressed as a weight percentage.
Total iron oxide converted to O ₃ and Ce of 0.8 to 1.2%
It contains O ₂ .

[0006]

However, all of the above-mentioned prior arts relate to glass having a relatively high degree of transparency, and provide a low-transmittance glass that can be used as a ceiling portion of a vehicle or for protecting privacy. Not a thing.

On the other hand, for example, JP-A-2-64038, JP-A-3-153543, JP-A-5-330847,
JP-A-6-247740 and US Pat. No. 5,30.
No. 8,805 discloses an attempt to produce transparent glass with low visible light transmission. These glasses contain about 10 to 100 ppm of selenium as a coloring essential component in order to reduce the visible light transmittance, but selenium accounts for most of the batch input amount (90% or more) in the melting process.
Is volatilized, 100-100
More than 00 ppm of selenium must be added.
However, since selenium is a highly toxic substance, melting a batch containing such a large amount of selenium is
Not preferable for environmental pollution prevention measures.

Further, low-transmission glass in the prior art (for example, JP-A-6-247740, US Pat. No. 5,3).
No. 08,805) contains nickel as a main colorant. However, nickel forms nickel sulfide stone having a large coefficient of thermal expansion during melting, which may cause thermal destruction during quenching and strengthening.

Further, the glass tones described in the above-mentioned prior art all exhibit neutral dark gray or gray blue color, and do not provide a low-transmittance glass having a greenish tone.

The present invention has been made in view of the above-mentioned problems of the prior art, and essentially contains, as a coloring component, selenium which is a harmful volatile component and nickel which has a possibility of forming nickel sulfide stone. It is an object of the present invention to provide a low-transmittance glass having a greenish color tone without performing the above process.

[0011]

That is, the present invention, expressed in weight percent, is 65-80% SiO ₂ , 0-5% A.
l ₂ O ₃ , 0-5% B ₂ O ₃ , 0-10% MgO, 5-
15% CaO, 10-18% Na ₂ O, 0-5% K ₂ O, 5-15% MgO + CaO, and 10-20
% Of Na ₂ O + K ₂ O and a coloring component of Fe ₂ O ₃ of 0.95 to 2.20% and a FeO / total iron oxide ratio of 0.13 to 0.30. Converted total iron oxide, 0.9 to 2.3% TiO ₂ , 0.010 to
It is composed of 0.020% CoO and 0 to 1.0% CeO ₂ , and more preferably 1.20 as the coloring component.
~ 2.00% and FeO / total iron oxide ratio of 0.14
~ 0.28 total iron oxide converted to Fe ₂ O ₃ , 1.0 ~
1.5% TiO ₂ , 0.010 to 0.020% Co
It is a low-transmittance glass characterized by comprising O and 0 to 1.0% CeO ₂ .

The low-transmittance glass of the present invention has a visible light transmittance of less than 38% measured in the wavelength range of 380 to 770 nm using the A light source of the glass converted to a thickness of 4 mm, and 380 to 770 nm using the C light source. Main wavelength measured in the wavelength range of 495 to 520 nm, stimulation purity of less than 10%, 300 to
It preferably has optical properties such that the total solar energy transmittance measured in the wavelength range of 2100 nm is less than 28%, and the total solar ultraviolet transmittance measured in the wavelength range of 300 to 400 nm is less than 15%.

The reasons for limiting the composition of the low-transmittance glass of the present invention will be described below. 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 decrease, and if it exceeds 80%, it will be difficult to melt the glass.

Al ₂ O ₃ is a component that improves 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%.

B ₂ O ₃ is used for improving the durability of the glass and as a melting aid, but may not be contained in the glass. If B ₂ O ₃ exceeds 5%, inconvenience at the time of molding due to volatilization of B ₂ O _{3 or} the like occurs, so the upper limit is 5%. $% MgO and CaO are used to improve the durability of glass and adjust the devitrification temperature and viscosity during molding. When MgO exceeds 10%, the devitrification temperature rises. C
If aO is less than 5% or exceeds 15%, the devitrification temperature rises. 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.

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

Iron oxide in glass exists in the state of Fe ₂ O ₃ and FeO. Total iron oxide converted to Fe ₂ O ₃ is 0.95
If it is less than%, the effect of absorbing ultraviolet rays and infrared rays is small and desired optical characteristics cannot be obtained. On the other hand, if it exceeds 2.2%, the temperature of the ground portion of the glass melt rises due to the heat ray absorption effect of ferrous oxide, and the radiant heat may cause the temperature rise at the ceiling of the melting tank to be higher than the heat resistant temperature of the brick. It is not preferable because it exists. The more preferable range is 1.2 to 2.0%.
Is.

In order to obtain the desired total solar energy absorption capacity and visible light absorption capacity under the above-mentioned total iron content,
It is important that the lower limit of the ratio of FeO / total Fe ₂ O ₃ is 0.13 or more, more preferably 0.14 or more, and the upper limit is 0.3 or less, more preferably 0.28 or less. However, if this ratio exceeds 0.30, the absolute amount of FeO increases too much, and the temperature of the glass melting tank approaching part rises too much, which is not preferable.

TiO ₂ is used as an ultraviolet absorbing component. If the concentration of TiO ₂ is less than 0.9%, sufficient ultraviolet absorption ability cannot be obtained, and if it exceeds 2.3%, the absorption of visible light on the short wavelength side becomes too large, and the glass becomes yellowish. The greenish color tone of will not be obtained. A more preferable range is 1.0 to 1.5%.

CoO is an essential component for obtaining a greenish color tone in the coexistence of TiO ₂ and for reducing the visible light transmittance. As described above, as the amount of TiO ₂ added is increased, the glass color changes from green to yellowish green or yellow. Such a change of the glass to a yellowish color tone due to the addition of TiO ₂ can be suppressed by the addition of CoO. However, the CoO concentration is 100 pp
If it is less than m, its suppressing effect is too small, while on the other hand, it is 200 ppm.
If it exceeds the range, the glass changes to a blue color tone, which is not preferable.

CeO ₂ is an ultraviolet absorbing component. However, when the concentration of CeO ₂ exceeds 1.0%, the absorption of visible light on the short wavelength side becomes too large, and the glass becomes yellowish, so that not only the desired green color tone cannot be obtained, but also glass production. This is not preferable because it increases the cost.

[0023]

The low-transmittance glass according to the present invention has a green color tone and has a low light transmittance in the ultraviolet region, the visible region and the infrared region.

[0024]

EXAMPLES Specific examples of the present invention will be described below.

(Example) A typical soda lime silica glass batch component was appropriately mixed with ferric oxide, titanium oxide, cobalt oxide, cerium oxide and a carbon-based reducing agent, and this raw material was heated in an electric furnace at 1500 ° C. It was heated and melted. After melting for 4 hours, pour the glass substrate onto a stainless steel plate,
The glass was gradually cooled to room temperature to obtain glass having a thickness of about 6 mm. Next, this glass was polished to a thickness of 4 mm to obtain a sample of this example.

Tables 1 and 2 show the total iron oxide concentration, FeO / T-Fe ₂ O ₃ ratio, TiO ₂ concentration, and C of the obtained samples.
The oO concentration, the CeO ₂ concentration and their optical characteristic values are shown, as well as the respective characteristic values of the obtained sample.

As is clear from Table 1, the sample of this example has a visible light transmittance of less than 38% measured using the A light source and a dominant wavelength measured using the C light source of 495 to 520n.
m, the stimulus purity is less than 10%, the total solar energy transmittance is less than 28%, and the ultraviolet transmittance is less than 15%.

[0028]

[Table 1]

[0029]

[Table 2]

Comparative Example Table 3 shows a comparative example for the present invention. In Comparative Example 1, total iron oxide concentration, TiO ₂
Both the concentration and the CoO concentration are below the concentration range proposed in the present invention. As a result, although the color tone of the glass in Comparative Example 1 was green (main wavelength 501.56 nm), the visible light transmittance, the ultraviolet light transmittance, and the sunlight transmittance were all beyond the range of the present invention. The low-transparency glass of the period has not been obtained.

In Comparative Example 2, only the total iron oxide concentration has a glass optical characteristic lower than the concentration range proposed in the present invention. The color tone of the glass in Comparative Example 2 is slightly greenish blue (main wavelength is 489.12 nm), and the visible light transmittance, the ultraviolet light transmittance, and the sunlight transmittance are all outside the range of the present invention. Therefore, the desired low-transmittance glass exhibiting a green color has not been obtained.

Further, in Comparative Example 3, the total iron oxide concentration, Ti
Although the O ₂ concentration is within the concentration range proposed in the present invention, Co 2
O was not added at all. It can be seen that the glass in Comparative Example 3 has a high visible light transmittance, and the color tone of the glass is green with a yellowish tint (main wavelength 561.54 nm). From this, it is understood that the addition of CoO is essential to obtain a desired greenish color tone and a low visible light transmittance.

[0033]

[Table 3]

[0034]

As described in detail above, the low-transmittance glass of the present invention can be produced without containing a coloring component such as selenium or nickel, which is a problem in glass production. Further, the low-transmittance glass of the present invention exhibits a greenish color tone, and thus is particularly suitable as a window glass for automobiles, and the use of the glass reduces the greenhouse effect inside the automobile, prevents deterioration of the interior, and protects privacy. The effect such as can be expected.

Claims (7)

[Claims] 1. 65-80% Si, expressed as wt%
O ₂ , 0-5% Al ₂ O ₃ , 0-5% B ₂ O ₃ , 0-1
0% MgO, 5-15% CaO, 10-18% N
a ₂ O, 0-5% K ₂ O, 5-15% MgO + Ca
O, and a basic glass composition consisting of 10 to 20% Na ₂ O + K ₂ O, and 0.95 to 2.20% as a coloring component.
And FeO / total iron oxide ratio converted to Fe ₂ O ₃ of 0.13 to 0.30, total iron oxide of 0.9 to 2.3% Ti.
O ₂ , 0.010 to 0.020% CoO, and 0
A low-permeability glass characterized by comprising 1.0% CeO ₂ . 2. As the coloring component, 1.20 to 2.0
0% and FeO / total iron oxide ratio of 0.14 to 0.2
No. 8 total iron oxide converted to Fe ₂ O ₃ , 1.0 to 1.5% TiO ₂ , 0.010 to 0.020% CoO, and 0
The low permeability glass of claim 1 consisting of ˜1.0% CeO ₂ . 3. The low-transmittance glass according to claim 1, which has a visible light transmittance of less than 38% as measured using a light source A of the glass converted into a thickness of 4 mm. 4. The low-transmittance glass according to claim 1, which has a dominant wavelength of 495 to 520 nm measured with a C light source of glass converted to a thickness of 4 mm. 5. The low-transmittance glass according to claim 1, wherein the ultraviolet transmittance of the glass converted into a thickness of 4 mm is less than 15%. 6. The low transparency glass according to claim 1 or 2, wherein the sunlight transmittance of the glass converted into a thickness of 4 mm is less than 28%. 7. The low-transmittance glass according to claim 1, which has a stimulus purity of less than 10% as measured by using a C light source of the glass converted into a thickness of 4 mm.