JPH04310539A - Infrared and ultraviolet absorbing glass - Google Patents

Abstract

PURPOSE:To provide a plate glass having high infrared absorption and ultraviolet absorption characteristics and sufficiently high visible light transmittance. CONSTITUTION:The objective infrared and ultraviolet absorbing glass is essentially composed of 65-75wt.% of SiO2, 0.1-5wt.% of Al2O3, 10-18wt.% of Na2O, 0-5wt.% of K2O, 5-15-wt.% of CaO, 1-6wt.% of MgO, 0.1-3.0wt.% of CeO2, 0.5-1.2wt.% of Fe2o3, 0.05-1.0wt.% of SO3 and 0-1.0wt.% of TiO2 (in terms of oxides), wherein ferrous oxide (FeO) accounts for 20-40wt.% of the total iron content expressed by Fe2O3.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention has high absorption of infrared rays.
The present invention also relates to the composition of infrared/ultraviolet absorbing glass having high visible light transmittance that can be used as automotive glass.

0002

BACKGROUND OF THE INVENTION Conventionally, ultraviolet and infrared absorbing glasses are known which are made of Ce3+ which absorbs ultraviolet rays and Fe2+ which absorbs infrared rays (Japanese Patent Publication No. 52-49010). However, the invention described in this publication was aimed at a medium-gray heat-absorbing glass, and therefore had insufficient absorption of infrared and ultraviolet rays.

[0003] When attempting to further increase the ultraviolet and infrared absorption performance of glass by combining these ions, it is essential to use a reducing agent to prevent this from occurring as Ce4+ oxidizes Fe2+ to Fe3+. It is. Carbon, metal powder, organic substances, etc. are generally used as this reducing agent. For example, in JP-A-64-18938, a carbon-containing material such as coal is used.

However, due to these reducing agents, Glauber's salt (Na2SO4), which is normally used as a fining agent in soda-lime-silica glass, is reduced and decomposed when the raw material is in a powder state at a relatively low temperature. The effect as a clarifying agent is lost. That is, it is very difficult to obtain a glass without bubbles. For this reason, the above-mentioned patent proposes a method of removing air bubbles under reduced pressure. However, degassing under reduced pressure requires special equipment, and although the reason is unknown, the degree of oxidation/reduction (Redox) of glass
It was difficult to stabilize the color tone and infrared absorption ability because of the change in color.

[0005] Furthermore, TiO
2 and using SnO2 as a reducing agent to increase the proportion of FeO2 in the total iron content has been proposed (U.S. Pat. No. 4,700).
No. 1,425). However, since this glass uses SnO2 as a reducing agent, there is a problem in that the cost of the glass increases.

[0006]

OBJECTS OF THE INVENTION The present invention has been made to eliminate the above-mentioned problems of the prior art. Moreover, the present invention provides an infrared and ultraviolet absorbing glass that has excellent infrared and ultraviolet absorption properties, and has sufficient visible light transmittance as automotive glass.

[0007]

[Means for Solving the Problems] The present invention has been made to achieve the above-mentioned problems, and the present invention has been made to achieve the above-mentioned problems.
68 ~ 73% Al2O3 0.1 ~ 5%
, preferably 1.0 to 5% Na2O
10-18%, preferably 12-15% K2
O 0-5%, preferably 0
~3%CaO5~15%, preferably 7~12%MgO1
~6%, preferably 2-5% CeO2
0.1 to 3.0%, preferably 0.3 to 3.0%
2.0%Fe2O3 0.5-1.2%
, preferably 0.7-1.0% SO3
0.05-1.0%, preferably 0.05-0.5
0% TiO2, consisting essentially of 0 to 1.0%, and characterized in that of the total iron content expressed as Fe2O3, 20 to 40% by weight is ferrous oxide (FeO). This provides infrared and ultraviolet absorbing glass.

Next, the reason for limiting each component constituting the composition of the infrared/ultraviolet absorbing glass of the present invention will be described below. S
When the proportion of iO2 is less than 65% by weight, weather resistance deteriorates, and when it is more than 75% by weight, devitrification tends to occur, and both are unfavorable. The proportion of Al2O3 is 0.1% by weight
If the content is less than 5% by weight, water resistance decreases, which is not preferable, and if the content exceeds 5% by weight, solubility decreases, which is not preferable.

[0009] Na2O and K2O are components that promote the dissolution of raw materials, but if Na2O is less than 10% by weight, the effect is small and undesirable, and if it is more than 18% by weight, weather resistance deteriorates, which is not preferred. In addition, K2O
By adding a small amount of , there is an effect of suppressing devitrification in addition to the above-mentioned effect, but if it is more than 5% by weight, the viscosity of the glass at high temperature becomes high and it becomes difficult to remove bubbles, which is not preferable.

[0010] CaO and MgO also promote the dissolution of raw materials,
Although CaO is a component that improves weather resistance, if it is less than 5% by weight, the above-mentioned effect will be small, and if it is more than 15% by weight, devitrification tends to occur, both of which are not preferred. Note that if a small amount of MgO is added, the above-mentioned effect will be enhanced, but if the amount is more than 6% by weight, devitrification tends to occur, which is not preferable.

The sulfur content is preferably 0.05 to 1.0% by weight expressed as SO3. SO3 is 0
．． In order to make it less than 0.05% by weight, the amount of sulfur compound as a clarifier must be reduced, which results in insufficient clarification and increases the number of residual bubbles, which is undesirable. Increasing the amount of glass is undesirable because the amount of similar sulfur compounds increases, and the sulfur reacts with components in the glass, resulting in a deep brown or amber color, making it impossible to obtain the desired visible light transmittance. .

Cerium oxide is a component that has the effect of absorbing ultraviolet rays for both Ce3+ and Ce4+, but CeO2
If it is less than 0.1% by weight, the effect will be small, and if it is more than 3% by weight, the effect will be saturated.
A range of 0.1% to 3% by weight is preferred. Also,
As a component having the effect of absorbing ultraviolet rays, TiO2, V2O5, or MoO3 may be added in a range of 0 to 1.0% by weight.

The total amount of iron in the glass composition in the present invention is 0.5 to 1.2% by weight expressed as Fe2O3.
It is preferable that it is in the range of . Of the total iron content expressed as Fe2O3, 20 to 40% by weight converted to Fe2O3 is in the form of ferrous oxide (Fe2O3).
(as O) is preferably present.

[0014] Iron exists in the glass in the Fe2+ and Fe3+ states, and the Fe2+ state has an absorption band for infrared rays and is a component that absorbs infrared rays. If FeO is less than 20% by weight in terms of Fe2O3 in the total iron content, the effect will be small;
If it exceeds 40% by weight in terms of e2O3, it becomes difficult to melt the glass homogeneously and the color of the glass becomes amber, which is not preferable.

[0015] Furthermore, one or more of NiO, CoO, MnO, V2O5, MoO3, etc. may be added as a coloring agent to the glass having the above-mentioned composition range in a total amount of 0 to 1.5% by weight. good. Furthermore, changes in color tone due to ultraviolet rays (solarizati)
ZnO may be added in an amount of 0 to 3% by weight, if necessary, to prevent the development of amber color.

[0016]

[Function] In the glass of the present invention, FeO in the total iron
However, the total amount of iron in the glass composition, expressed as Fe2O3, is 0.5 to 1.2% by weight, although the reduction ratio is maintained at approximately the same level as the reduction ratio of ordinary float glass plates. By increasing the iron content to a value higher than that of ordinary glass, the absolute amount of ferrous oxide (FeO 2 ), which has high infrared absorption performance, can be increased and the infrared absorption performance can be improved.

Therefore, ferrous oxide (FeO
) Glass with high infrared absorption performance can be obtained without using special reduction conditions to increase the reduction ratio higher than usual, for example, to 50% or more. Therefore, a plate glass can be manufactured by a conventional float glass manufacturing process under normal plate glass melting conditions and using a normal fining agent such as Glauber's salt.

[0018] Also, as mentioned above, since the reduction rate is low,
Particularly strong reducing conditions are not required, and therefore it is possible to prevent the occurrence of amber or brown color due to the reaction between the iron component and the sulfur component, and the accompanying decrease in transmittance. Therefore, it is not necessary to maintain a particularly low sulfur content during dissolution, and Glauber's salt (Na2SO4), which is effective in removing air bubbles during dissolution, can be effectively used as a refining agent.

[0019]

[Example] Main raw materials are silica sand, feldspar, limestone, dolomite, magnesium hydroxide, soda ash, and mirabilite, ferric oxide powder, cerium oxide powder, titanium oxide powder, carbon powder as a reducing agent, and coloring agent. As Ni, Co, Mn, V,
Mo oxide powder was used. In addition, as a raw material, for example, Glauber's salt may be used in place of another complex compound such as a sulfuric acid compound, or it may be used in combination with Glauber's salt and the above-mentioned complex compound. 500g of a mixture (batch) prepared by blending the above raw materials to the target composition was heated at 1500°C for 30 minutes using an electric furnace.
The mixture was dissolved for a period of time, poured into molds, and slowly cooled. Table 1 shows the results of measuring the optical properties and the number of remaining bubbles of the plate glass sample thus obtained.

Further, as a comparative example, the optical properties and the number of remaining bubbles of a plate glass sample prepared and melted in the same manner are summarized in Table 1. The optical properties are the values measured on a sample with a thickness of 5 mm, and the symbol TVa in the table is the visible transmittance (380 to 780 nm), and TE is the solar radiation transmittance (
340 to 1800 nm), Dw represents the dominant wavelength, and Pe represents the color purity. Further, FeO/Fe2O3 indicates the ratio of the value of FeO in the sample converted to Fe2O3 to the value of the total iron content in the sample converted to Fe2O3.

[0021]

[Table 1]

[0022]

Effects of the Invention: The glass of the present invention has a high visible light transmittance, so it does not impair the driver's visibility, and it absorbs infrared rays, improving heating and cooling effects.It also absorbs ultraviolet rays, so it can be used as an interior material for automobiles due to ultraviolet rays. It is particularly useful as window glass for buildings, vehicles, etc. because it reduces the adverse effect on seats, passengers' skin, and the like.

The infrared/ultraviolet absorbing glass of the present invention also absorbs infrared rays with Fe2+, and absorbs ultraviolet rays with Ce3+ and Ce3+.
4+, while reducing the reducing conditions to a low level so that the proportion of ferrous oxide in the total iron content is 20% to 40% by weight. 530 nm can be easily obtained, and it is also possible to use glauber's salt as a fining agent.Since mirabilite can be used as a fining agent, it is possible to use conventional glass melting equipment, such as float glass, without using special equipment. Manufacturing equipment can be used, and therefore bubble-free glass plates can be manufactured easily, inexpensively, and with high production efficiency.

Claims (1)

[Claims] Claim 1: SiO2 65 to 75 in terms of the following oxide
Weight% Al2O3 0.1-5
Weight% Na2O 10 ~
18 Weight% K2O
0 to 5% by weight CaO
5 to 15% by weight MgO
1 to 6 wt% CeO2
0.1~3.0 wt%Fe2O
3 0.5 ~ 1.2 wt%S
O3 0.05-1.0 wt% TiO2 0-1.0
20-40% by weight of the total iron content consisting essentially of % by weight and expressed as Fe2O3
An infrared/ultraviolet absorbing glass characterized in that ferrous oxide (FeO) is ferrous oxide (FeO).