JPH08217486A - Ultraviolet and infrared absorbing glass - Google Patents

Abstract

PURPOSE: To obtain ultraviolet and infrared absorbing glass having green-based color tone whose main wavelength is <520nm without using expensive cerium oxide which is an oxidizing agent. CONSTITUTION: This glass is constituted of a base glass composition comprising 65-80wt.% SiO2 , 0-5wt.% Al2 O3 , 0-5wt.% B2 O3 , 0-10wt.% MgO, 5-15wt.% CaO, 10-18wt.% Na2 O, 0-5wt.% K2 O, 5-15wt.% MgO+CaO and 10-20wt.% Na2 O+K2 O, and 0.5-0.9wt.% (in terms of Fe2 O3 ) total iron oxide having 0.22-0.38 ration of FeO/total iron oxide, 0.1-1.2wt.% TiO2 and 0.0001-0.0020wt.% CoO as coloring components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ultraviolet and infrared absorbing glass. More specifically, the present invention relates to an ultraviolet and infrared absorbing glass having a greenish color tone, which can be produced without containing expensive raw materials such as cerium oxide.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of demand for prevention of deterioration of interior materials due to upsizing of interior materials for automobiles and reduction of cooling load,
As a window glass for automobiles, a glass having a greenish color tone imparted with an ultraviolet and infrared ray absorbing ability has been proposed.

For example, the ultraviolet transmittance is limited to about 38% or less, and the total sunlight energy transmittance is limited to about 46% or less,
Further, there is known one having a visible light transmittance of at least 70% in order to secure a visual field from the inside of an automobile.

To reduce the total solar energy transmission,
Of the iron oxides introduced into the glass, ferrous oxide (Fe
It is known that the absolute amount of (O) should be increased,
Most of the infrared absorbing glasses proposed in the past employ this method.

On the other hand, various methods for reducing the ultraviolet transmittance have been proposed conventionally. For example, Japanese Patent Laid-Open No. 3-18
The ultraviolet absorbing glass having a green color tone disclosed in 7946 uses cerium oxide and titanium oxide. That is, as a mother composition, expressed as a weight percentage, 65 to 75% of SiO ₂ , 0 to 3% of Al ₂ O ₃ , 1 to 5
% MgO, 5-15% CaO, 10-15% Na
_In a glass containing ₂ O and 0 to 4% of K ₂ O, 0.51 to 0.96% as a coloring component and FeO / T-Fe
Total iron oxide ₂ O ₃ ratio in terms of Fe ₂ O ₃ is 0.23 to 0.29, from 0.2 to 1.4% of CeO _2, and 0-0.
It contains 85 TiO ₂ .

Further, the ultraviolet absorbing glass having a greenish color tone disclosed in JP-A-6-56466 is a soda
The lime-silica base glass composition has a coloring component of 0.
In 53 to 0.70%, and the total iron oxide FeO / T-Fe ₂ O ₃ ratio in terms of Fe ₂ O ₃ is 0.30 to 0.40, from 0.5 to 0.8% of CeO ₂ , And 0.2 to 0.4
TiO ₂ is included.

Further, the ultraviolet absorbing glass having a greenish color tone disclosed in JP-A-4-231347 has a soda-lime-silica-based mother glass composition with 0.85% or more as a coloring component and FeO. / T-Fe ₂ O ₃ ratio is zero.
Less than 275, total iron oxide converted to Fe ₂ O ₃ ,
It contains less than 5% CeO ₂ .

As described above, most of the ultraviolet and infrared absorbing glasses having a greenish color tone in the prior art contain cerium oxide as an ultraviolet absorbing agent. However, since cerium oxide is expensive, the raw material cost is substantially increased when it is used as an ultraviolet absorber.

From the above viewpoints, a method for obtaining an ultraviolet and infrared absorbing glass without using cerium oxide has been newly proposed.

For example, Japanese Patent Laid-Open No. 6-191881 discloses that
As a method for obtaining an ultraviolet and infrared radiation absorbing glass only with titanium oxide without the use of cerium oxide, soda - lime - mother glass composition of the silica-based, it exceeds 0.6% as coloring components, and FeO / T-Fe ₂ O ₃ ratio Fe ₂ O ₃ with a value of less than 0.35
It describes a UV-infrared absorbing glass having a light greenish color tone by containing the total iron oxide converted to the above and TiO ₂ of less than 2.0%.

[0011]

Titanium oxide interacts with iron oxide in glass and contributes to the absorption of ultraviolet rays, but its absorption band extends somewhat to the short wavelength side of the visible region. Therefore, when titanium oxide is used to secure the desired UV absorption capacity, the color tone of the glass exhibits a slightly yellowish green color, and as a result, the dominant wavelength of the glass shifts to the long wavelength side of 520 nm or more. There is. However, considering that glass having a main wavelength of less than 520 nm and a greenish color tone is generally preferred as glass for vehicles, the use of titanium oxide alone cannot be said to be sufficient.

The present invention has been made in view of the above-mentioned conventional problems, and it does not use cerium oxide, which is an oxidizing agent and is expensive, and has ultraviolet rays having a greenish color tone with a dominant wavelength of less than 520 nm. It is intended to provide an infrared absorbing glass.

[0013]

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 Fe ₂ O ₃ of 0.5 to 0.9% and a FeO / total iron oxide ratio of 0.22 to 0.38 as a coloring component. Converted total iron oxide, 0.1 to 1.2% TiO ₂ , and 0.0001 to
It is composed of 0.0020% CoO, more preferably 0.6 to 0.9% as the coloring component, and converted into Fe ₂ O ₃ having a FeO / total iron oxide ratio of 0.23 to 0.38. Total iron oxide, 0.2-1.2% TiO ₂ , and 0.000
It is an ultraviolet-infrared ray absorbing glass characterized by comprising 1 to 0.0015% CoO.

The UV-infrared absorbing glass of the present invention has a thickness of 38 mm by using a glass A light source converted to a thickness of 4 mm.
The visible light transmittance measured in the wavelength range of 0 to 770 nm is 70.
% Or more, the dominant wavelength measured in the wavelength range of 380 to 770 nm using a C light source is 495 to 520 nm, and the stimulation purity is 2 to
3%, total solar energy transmittance measured in the wavelength range of 300 to 2100 nm is less than 47%, 300 to 400 nm
It is preferable to have optical characteristics in which the total solar ultraviolet light transmittance measured in the wavelength range of is less than 38%.

The reasons for limiting the composition of the ultraviolet and infrared absorbing 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 to adjust the devitrification temperature and viscosity during molding. When MgO exceeds 10%, the devitrification temperature rises. When CaO 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. When the content of Na ₂ O is less than 10% or the total content 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 O
If the total amount of O exceeds 20%, the durability of 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. 0.5% of total iron oxide converted to Fe ₂ O ₃
If it is less than the above, 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 0.9%, the desired visible light transmittance cannot be obtained. More preferably 0.6 to 0.
It is in the range of 9%.

Under the above-mentioned total iron content, FeO / total Fe ₂
The lower limit of the ratio of O ₃ is 0.22 or more, more preferably 0.2.
It is important to set it to 3 or more and to set the upper limit to 0.38 or less. However, if this ratio exceeds 0.38, Fe
A desired visible light transmittance cannot be obtained because the absolute amount of O increases too much.

TiO ₂ is used as an ultraviolet absorbing component. If the content of TiO ₂ is less than 0.1%, sufficient ultraviolet absorption ability cannot be obtained, and if it exceeds 1.2%, the absorption of visible light on the short wavelength side becomes too large, and the glass becomes yellowish. The light transmittance and the dominant wavelength cannot be obtained. A more preferable range is 0.2 to 1.2%.

CoO is an essential component for obtaining a greenish color tone. It has been conventionally considered that the addition of TiO ₂ as an ultraviolet absorber to glass containing Fe ₂ O ₃ has a drawback that the glass color changes from usable green to unusable yellow green or yellow. However, in the present invention, C
It was found that by adding oO, the desired greenish color tone can be obtained even when TiO ₂ coexists. But,
If the CoO concentration is less than 1 ppm, it is insufficient to obtain a green color tone. On the other hand, if it exceeds 20 ppm, not only the glass changes from a green color tone to a blue color tone, but also the visible light absorption capacity becomes too large. It is not preferable because the desired visible light transmittance cannot be secured. The more preferable range is 1 to 15 ppm.

[0025]

The ultraviolet / infrared absorbing glass according to the present invention has a greenish color tone and exhibits high ultraviolet absorbing ability, infrared absorbing ability and visible light transmittance.

[0026]

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

(Example) Ferric oxide, titanium oxide, cobalt oxide and a carbon-based reducing agent were appropriately mixed with a typical soda-lime-silica glass batch component, and this raw material was heated to 1500 ° C. in an electric furnace. Melted After melting for 4 hours, the glass substrate was poured onto a stainless plate and 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.

Table 1 shows the total iron oxide concentration, the FeO / T-Fe ₂ O ₃ ratio, the TiO ₂ concentration, the CoO concentration and the optical characteristic values of the obtained sample, and the respective characteristic values of the obtained sample. Indicates.

As is clear from Table 1, the sample of this example has a visible light transmittance of 70% or more 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 2 to 3%, the total solar energy transmittance is less than 47%, and the ultraviolet transmittance is less than 38%.

[0030]

[Table 1]

Comparative Example Table 2 shows a comparative example for the present invention. Further, the optical characteristics of the glass of the comparative example, which has the same composition as that of the example and is melted without adding only cobalt oxide, are shown.
As is clear from Table 2, in all the comparative examples, the dominant wavelength is 5
It is 20 nm or more, and it can be seen that the desired greenish color tone is not obtained.

[0032]

[Table 2]

[0033]

As described in detail above, the ultraviolet-infrared ray absorbing glass of the present invention can be manufactured at low cost because cerium oxide is not used as an ultraviolet ray absorbing agent. Further, the ultraviolet-infrared absorbing glass of the present invention retains a greenish color tone, and is therefore particularly useful as a window glass for automobiles.

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 a coloring component of 0.5 to 0.9%, and a FeO / total iron oxide ratio of 0.22 to 0.38. Fe ₂
Total iron oxide converted to O ₃ , 0.1 to 1.2% TiO ₂ ,
And 0.0001 to 0.0020% CoO. 2. The coloring component is 0.6 to 0.9%
And FeO / total iron oxide ratio 0.23 to 0.38 converted to Fe ₂ O ₃ total iron oxide, 0.2 to 1.2% Ti
The ultraviolet / infrared absorbing glass according to claim 1, comprising O ₂ and 0.0001 to 0.0015% CoO. 3. The ultraviolet / infrared absorbing glass according to claim 1, which has a visible light transmittance of 70% or more as measured using a light source A of the glass converted to a thickness of 4 mm. 4. The ultraviolet and infrared absorbing glass according to claim 1, which has a dominant wavelength of 495 to 520 nm measured by using a glass C light source converted to a thickness of 4 mm. 5. The ultraviolet / infrared absorbing glass according to claim 1, wherein the ultraviolet transmittance of the glass converted to a thickness of 4 mm is less than 38%. 6. The ultraviolet / infrared absorbing glass according to claim 1 or 2, wherein the glass has a solar light transmittance of less than 47% converted to a thickness of 4 mm. 7. The ultraviolet / infrared absorbing glass according to claim 1, which has a stimulus purity of 2 to 3% as measured using a C light source of glass converted to a thickness of 4 mm.