JP2003002683A - Low-transmittance glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-transmittance glass having excellent heat-absorbing properties, high quality and excellent productivity, which is suitable for a window glass used for a passenger car produced by air cooling and tempering. SOLUTION: The low-transmittance glass comprises a soda lime glass comprising 0.001-2 wt.% Li2 O and 0.7-2.2 wt.% total iron oxide (T-Fe2 O3 ) on Fe2 O3 basis as a color component, wherein the glass having a thickness between 2.1-6 mm has a visible light transmission (YA) of 65% or lower, a total sun light transmission (TG) of 60% or lower, and UV transmission (Tuv) defined in ISO of 25% or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low transmission glass having excellent heat ray absorption performance, high quality and excellent productivity. More specifically, it relates to a glass having a low visible light transmittance having a gray to greenish dull color tone and a high heat ray absorption performance, and particularly to a low transmission glass suitable as a window glass used in a passenger car by being tempered by wind cooling.

[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, various glasses having ultraviolet and infrared absorbing ability have been proposed. Among them, since the rear window glass of an automobile is required to protect privacy in addition to passenger comfort, it is preferable to use glass with low visible light transmittance (low transmission glass).

As a glass having the above characteristics, the inventors have proposed some UV-infrared-absorbing and low-transmitting glasses having low to moderate visible light transmittance, low UV transmittance, and low total sunlight transmittance. (For example, Japanese Patent Laid-Open No.
-114540 gazette etc.).

In such an ultraviolet and infrared ray absorbing and low transmitting glass, the productivity was low due to its high heat ray absorbing performance. That is, in a melting kiln that directly heats the kiln from the top of the kiln, the heat rays incident from the upper surface of the glass base due to the radiation of the flame are significantly absorbed by the glass base of the upper layer, so the glass base of the lower layer is sufficiently heated. Therefore, it was difficult to melt and homogenize the glass substrate.

In order to solve the above-mentioned problems, conventionally, the measures have been taken by improving the glass manufacturing process. For example, the amount of glass base in the kiln is reduced from that during normal operation, or the electrode inserted in the bottom of the kiln is energized to heat the glass base in the low-layer part, or air is blown into the glass base (bubbling). The above methods have been used alone or in combination to promote the melting and homogenization of the glass substrate.

However, reducing the amount of glass base material from that during normal operation leads to a reduction in production capacity and increases the manufacturing cost of glass. Also, in the case of electric heating to insert an electrode into the bottom of the kiln or air supply into the glass base,
Equipment modification for that is required. Further, all of these process changes have a problem that a large amount of defects such as bubbles are generated in the glass depending on the operating conditions, which causes a remarkable decrease in production efficiency.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and is intended to promote melting and homogenization of a glass base material by reducing the viscosity of the glass base material, It is an object of the present invention to provide a low transmission glass having high quality, excellent productivity and low infrared transmittance. Furthermore, when subjected to wind-cooling strengthening, a higher surface compressive stress value than before can be obtained, so the strengthening property is also excellent,
On the other hand, it is an object of the present invention to provide a low-transmission glass suitable as a rear window glass used especially for passenger cars because it has low visible light transmittance and ultraviolet transmittance as optical characteristics.

[0008]

The low transmission glass of the present invention is a soda lime type glass, containing 0.001 to ₂ % of Li ₂ O expressed by weight%, and as a coloring component, It includes total iron oxide in terms of 0.7 to 2.2% of _{Fe 2 O 3 (T-Fe} 2 O 3), of the glass in any one of the thickness of 2.1～6Mm, the a light source Visible light transmittance (YA) measured using 65% or less, total sunlight transmittance (TG) is 60% or less, and the ultraviolet transmittance (Tuv) specified by ISO is 25% or less. Characterize.

The low transmission glass of the present invention has excellent heat ray absorption.
It has high performance and Li as a basic glass component ₂Contain O
Reduces the viscosity of the glass substrate and promotes melting and homogenization.
Advanced, high quality, high productivity, and also excellent in strengthening
Realizes low transmission glass.

Further, the basic glass composition of the low transmission glass of the present invention is expressed in% by weight, and is 65 to 80% of SiO ₂ ,
0-5% Al ₂ O ₃ , 0-10% MgO, 5-15%
CaO (however, the total amount of MgO and CaO is 5-15
%), 10 to 20% Na ₂ O, 0 to 5% K ₂ O (however, the total amount of Na ₂ O and K ₂ O is 10 to 20%), and 0 to 5% B ₂ O. It is preferably composed of ₃ .

The low transmission glass of the present invention preferably contains at least one of Se, CoO, Cr ₂ O ₃ and NiO as a coloring component. A preferable content of Se is 0.0001 to 0.1% by weight, a preferable content of CoO is 0.0001 to 0.1% by weight, a preferable content of Cr ₂ O ₃ is 0.001 to ₂ % by weight, and NiO is preferable. The preferred content of is 0.001 to 2% by weight.

The low transmission glass of the present invention comprises TiO ₂ , CeO ₂ , MoO ₃ , V ₂ O ₅ and La ₂ O as coloring components.
_At least one component in the group consisting of ₃ is 0.0
It is preferable to contain 001 to 1% by weight.

The low transmission glass of the present invention as described above is 2.
A of glass in any one thickness of 1 to 6 mm,
Visible light transmittance (YA) measured using a light source is 5 to 65
%, The total sunlight transmittance (TG) is 50% or less, and I
The ultraviolet transmittance (Tuv) defined by SO is preferably 20% or less.

[0014]

The reasons for limiting the low transmission glass composition of the present invention will be described. However, the following compositions are expressed in% by weight.

Li ₂ O is a component that lowers the viscosity of the glass substrate and improves productivity. Further, Li ₂ O has the effect of increasing the thermal expansion coefficient and Young's modulus of the glass when the addition amount is within a certain range, and therefore increases the surface compression stress of the glass when the glass is tempered by wind cooling. It is also a component that improves the strengthening property of glass.

When the amount of Li ₂ O is 2% or less, Li ₂ O
As the amount increases, the viscosity of the glass substrate decreases, and glass with excellent productivity can be obtained. However, in the region where it exceeds 2%, the effect of decreasing the viscosity becomes small even if the amount of Li ₂ O increases. If the amount of Li ₂ O is less than 0.001%, the effect cannot be expected sufficiently. FIG. 1 shows the relationship between the amount of Li ₂ O and the temperature at which log η = 2 in a general soda-lime type silica glass. It can be seen that the temperature at which log η = 2 decreases monotonically as the amount of Li ₂ O increases, and that the slope becomes smaller when the amount exceeds 2%. Therefore, the Li ₂ O content in the present invention is 0.001% to 2%. Li ₂
Since the O raw material is expensive, L
The i ₂ O amount is preferably less than 2%.

In the region where the content of Li ₂ O is 0.5% or less, the surface compressive stress value of the glass after the air-cooling tempering increases as the amount of Li ₂ O increases. However, in the region exceeding 0.5%, the surface compressive stress value of glass hardly changes even if the amount of Li ₂ O increases. FIG. 2 shows the relationship between the Li ₂ O content and the surface compressive stress value of glass in a typical soda-lime silica glass. Surface compressive stress value in accordance with Li ₂ O increases is increased but, Li ₂ O content is 0.5%
It can be seen that the surface compressive stress value hardly changes when the value exceeds. Therefore, considering the balance between cost and effect, Li ₂ O is preferably 0.5% or less. L
When it is expected that the surface compressive stress value of the glass is increased by the addition of i ₂ O, it is preferable to add 0.05% or more.

Iron oxide is Fe in glass.₂O₃And FeO
Exists in the state of. Fe₂O₃Is a component that enhances UV absorption
FeO is a component that enhances the infrared absorption ability.
Fe ₂O₃Total iron oxide (T-Fe)₂O₃) Is 0.7
If it is less than%, the effect of absorbing ultraviolet rays and infrared rays is small,
The desired optical characteristics cannot be obtained. On the other hand, T-Fe₂O₃Is 2.
If it exceeds 2%, its infrared absorption capacity is too large, and
Production in the kiln becomes difficult. Also, the color tone is more green.
Less preferred. Furthermore, T-Fe₂O₃With a lot of glass
When producing continuously in a melting kiln, glass of different composition
It is not preferable because it takes time to change the composition with the base material.

In the present invention, the coexistence of FeO and Li ₂ O in soda lime glass has the effect of shifting the absorption peak of FeO to the shorter wavelength side. In order to show this, FIG. 3 shows a plot of the relationship between the amount of Li ₂ O and the transmittance at 700 nm. It can be seen that the transmittance at 700 nm decreases as the amount of Li ₂ O increases. Fe less due to the addition of Li ₂ O
O can effectively reduce the visible light transmittance.

Fe₂O₃T-Fe of FeO converted to₂O₃
To the weight ratio (FeO / T-Fe ₂O₃Ratio) is not 20%
When it is full, sufficient heat ray absorbing ability cannot be obtained. On the other hand, FeO
/ T-Fe₂O₃If the ratio exceeds 50%, the glass substrate is strong.
Since it depends on the reducing side, silica-rich streaks and
This is not preferable because it causes the recurs cam and decreases the production efficiency.
Yes.

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 that improves the durability of the glass, but if it exceeds 5%, melting of the glass becomes difficult.

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 accelerate the melting of the glass. 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 20%, or the total of Na ₂ O and K ₂ O is 2
If it exceeds 0%, the durability of the glass decreases. If the amount of K ₂ O is large, the cost becomes high, so it is desirable to keep K ₂ O at 5% or less.

B ₂ O ₃ is a component used for improving the durability of glass or as a solubilizing agent, but also has a function of enhancing absorption of ultraviolet rays. When B ₂ O ₃ exceeds 5%,
5% because inconvenience during molding occurs due to volatilization of B ₂ O ₃
Is the upper limit.

Se, CoO, Cr ₂ O ₃ and NiO are components for adjusting the visible light transmittance and the color tone, and at least one of them is preferably contained.

Se is a component that imparts a red to pink color tone to glass, and a grayish color tone can be obtained by coexisting with FeO or CoO. When Se is contained, if it exceeds 0.1%, the visible light transmittance is too low,
The desired characteristics cannot be obtained. The preferred content is 0.000
It is 1 to 0.1%.

CoO is a component that imparts a blue color to glass, and a grayish color tone can be obtained by coexisting with Se, NiO, or Fe ₂ O ₃ . When CoO is contained, if it exceeds 0.1%, the visible light transmittance is excessively lowered, and desired characteristics cannot be obtained. The preferred content is 0.
It is 0001 to 0.1%.

Cr ₂ O ₃ is a component that imparts a green color to the glass, and coexists with Se, NiO, CoO or Fe ₂ O ₃ to adjust the visible light transmittance and the color tone.
If it exceeds 2%, the visible light transmittance is too low to obtain desired characteristics. The preferred content is 0.001 to 2%.

NiO is a component which imparts a brown to purple color tone to glass, and a grayish color tone can be obtained by coexisting with FeO or CoO. If it exceeds 2%, the visible light transmittance is excessively lowered, so that desired optical characteristics cannot be obtained and the possibility of nickel sulfide stone formation is increased, which is not preferable. The preferred content is 0.001 to 2%.

Further, in order to obtain more preferable color tone and characteristics, TiO ₂ , CeO ₂ , MoO ₃ , V ₂ O ₅ and La ₂ O _{3 are} used as auxiliary UV absorbers in the glass of the composition range of the present invention. You may add 0.0001-1% of at least 1 type of component of a group.

It is generally known that an alkali or alkaline earth metal sulfate is used as a fining agent,
The glass contains about 0.1 to 0.5% SO ₃ . One or more kinds of Sb ₂ O ₃ , SnO _{2 and the} like may be added as a reducing agent or a clarifying agent in a total amount of 1% or less. Further, ZnO may be added in an amount of 1% or less for the purpose of further reliably preventing the generation of nickel sulfide stones.

The low transmission glass of the present invention as described above is
C of glass in any one thickness of 1 to 6 mm
Visible light transmittance (YA) measured using the A light source of IE is 65% or less, total sunlight transmittance (TG) is 60% or less, I
The ultraviolet transmittance (Tuv) specified by SO is 25% or less. This YA is preferably 5 to 65%, and T
G is preferably 50% or less, and Tuv is preferably 20% or less.

[0034]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. (Examples 1 to 10) Table 1 shows the amounts of typical soda lime-based silica glass raw materials prepared. Lithium oxide, ferric oxide, metal selenium, cobalt oxide, chromium oxide, nickel oxide, titanium oxide, cerium oxide, molybdenum oxide, vanadium pentoxide, and lanthanum oxide are appropriately mixed with this, and this raw material is heated in an electric furnace for 1500 Hold at ℃ for 4 hours,
Melted Then, the glass substrate was poured onto a stainless steel plate, held at 650 ° C. for 1 hour, and then allowed to cool to room temperature in the furnace to obtain a glass plate having a thickness of about 6 mm.

[0035]

[Table 1]

Then, the obtained glass plate was made to have a thickness of 3.5.
The sample was polished to a size of ˜5 mm, and the optical characteristics were visible light transmittance (YA) measured using a CIE standard A light source, total sunlight energy transmittance (TG), and I.
Ultraviolet transmittance (Tuv) specified by SO, dominant wavelength (DW) measured using a CIE standard C light source, stimulation purity (P
e) was measured.

As physical properties, glass transition temperature (Tg), deformation temperature (Td), average thermal expansion coefficient (α _(50-350) ) at 50 ° C to 350 ° C, Young's modulus (E), surface compressive stress. The temperature at which the value log η = 2 was measured. Mold each sample to a length of 15 mm and a diameter of 5 mm,
Using EXSTAR6000 manufactured by Seiko Instruments Inc., using quartz glass as a standard sample, a temperature rising rate of 10 ° C./minute,
By measuring from room temperature to 700 ° C. under a load of 5 g, the glass transition temperature (Tg) and the deformation temperature (T
d), the average coefficient of thermal expansion at 50 ° C to 350 ° C (α
_(50-350) ). When Young's modulus (E) is measured by the sing-around method using ultrasonic waves, the surface compressive stress value is measured by the Biascope method using a Babinet-type surface stress meter, and when log η = 2 by the method of pulling down a platinum ball. Was measured.

Tables 2 and ₃ show the basic glass composition, colorant concentration, FeO / T-Fe ₂ O ₃ ratio, optical characteristic value and physical characteristic value of each sample. In addition, the composition indication in the table is% by weight.

[0039]

[Table 2]

[0040]

[Table 3]

Examples 1-10 are glasses having composition and optical properties within the scope of claim 1. These examples are also within the compositional ranges set forth in claims 4 and 5. As is clear from Tables 2 and 3, the low transmission glass of the present invention is a glass having a low temperature when log η = 2, which is an index showing high temperature viscosity, and excellent in solubility, and has a surface compressive stress value. It is a glass that is highly tough and strong.

Further, Examples 1 to 10 are glasses having compositions within the preferable ranges of Claims 6 and 11, and have a visible light transmittance (YA) of 5 measured using an A light source.
~ 65% or less, total solar energy transmittance (TG) is 50
% Or less and UV transmittance (Tuv) specified by ISO
Has a preferable optical property of not more than 20%. In these examples, the dominant wavelength (DW) measured using a C light source was 490 to 560 nm, and the stimulation purity (P
e) is also a glass having a color tone of 9% or less.

Examples 1 and 3 to 9 are compositions in the preferred range of claim 2, and Examples 3 to 7 are compositions in the preferred range of claim 3. These examples are glasses that have a good balance of cost and effectiveness.

Comparative Examples 1 and 2 Table 4 shows the glass composition, optical characteristics and physical characteristics of Comparative Examples prepared in the same manner as in Examples 1 to 10 except for the glass composition.

[0045]

[Table 4]

Comparative Examples 1 and 2 are conventional low transmission glasses containing no Li ₂ O. Compared with the glass of the present invention, these glasses have a high temperature at which log η = 2 and a low surface compressive stress value, and thus are inferior in productivity and temperability.

[0047]

As described in detail above, according to the present invention,
A low transmission glass composition having excellent heat ray absorption performance and excellent productivity is provided. More specifically, a low visible light glass having a gray to greenish dull color tone and a high heat ray absorption performance, and particularly a low transmission glass suitable as a window glass used in a passenger car by being tempered by wind cooling is provided.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the Li ₂ O content and the temperature when log η = 2.

FIG. 2 is a graph showing the relationship between the Li ₂ O content and the surface compressive stress value.

FIG. 3 is a graph showing the relationship between the Li ₂ O content and the transmittance at 700 nm.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C03C 3/091 C03C 3/091 (72) Inventor Nobuyuki Yamamoto 4-7 28 Kitahama, Chuo-ku, Osaka City, Osaka Japan Sheet Glass In-house F-term (reference) 4G062 AA01 BB03 DA06 DA07 DB01 DB02 DB03 DC01 DC02 DC03 DD01 DE01 DF01 EA04 EB01 EC01 EC02 EC03 ED01 ED02 ED03 EE03 EE04 EF01 EG01 FA01 FB02 FC01 F01 F01 F01 F01 F01 F01 F01 F01 F01 F01 F02 F01 F01 F01 F01 F01 F01 F01 F01 F02 F01 F01 F02 F01 F01 F01 F01 F02 F01 F01 F02 HH01 HH03 HH05 HH07 HH08 HH09 HH11 HH12 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM01 NN05 NN07 NN10 NN12

Claims (12)

[Claims] 1. A soda lime type silica glass, comprising:
In% by weight, comprises from 0.001 to 2% of Li ₂ O, as coloring components, the total iron oxide in terms of 0.7 to 2.2% of _{Fe 2 O 3 (T-Fe} 2 O 3 ) Is included, 2.1-6m
The visible light transmittance (YA) measured using the A light source of the glass in any one of the thicknesses of m is 65% or less, and the total sunlight transmittance (TG) is 60% or less, and is specified in ISO. A low-transmission glass having a UV transmittance (Tuv) of 25% or less. 2. A Li ₂ O content of less than 2% by weight.
The low transmission glass described in. 3. The low transmission glass according to claim 1, wherein the content of Li ₂ O is 0.05 to 0.5% by weight. 4. FeO converted to Fe ₂ O ₃ is T-Fe ₂
The low transmission glass according to claim 1, which is 20 to 50% of O ₃ . 5. The basic glass composition, expressed in% by weight,
65-80% SiO ₂ , 0-5% Al ₂ O ₃ , 0-1
0% MgO, 5-15% CaO (however, the total amount of MgO and CaO is 5-15%), 10-20% Na ₂
O, 0-5% K ₂ O (where the total amount is 10-20% of Na ₂ O and K ₂ O), and one 0-5% of B ₂ O ₃ consisting of claims 1 to 4 The low transmission glass according to item 1. 6. Se, CoO, Cr ₂ as a coloring component
The low transmission glass according to claim 1, containing at least one of O ₃ and NiO. 7. The low transmission glass according to claim 6, wherein Se is 0.0001 to 0.1% by weight. 8. The low transmission glass according to claim 6, wherein CoO is 0.0001 to 0.1% by weight. 9. The low transmission glass according to claim 6, wherein Cr ₂ O ₃ is 0.001 to ₂ % by weight. 10. The low transmission glass according to claim 6, wherein NiO is 0.001 to 2% by weight. 11. A coloring component such as TiO ₂ , CeO ₂ ,
The low transmission glass according to claim 1, which contains 0.0001 to 1% by weight of at least one component selected from the group consisting of MoO ₃ , V ₂ O ₅ and La ₂ O ₃ . 12. A glass having a thickness of any one of 2.1 to 6 mm has a visible light transmittance (YA) measured using an A light source of 5 to 65% and a total sunlight transmittance (TG).
Is 50% or less, and the ultraviolet transmittance (Tuv) specified by ISO is 20% or less. The low transmission glass according to claim 1.