JPH0551235A - Colored low expansion transparent crystallized glass - Google Patents

Abstract

PURPOSE:To obtain a fine color tone and to increase IR absorption factor, heat ray absorbing ability and UV absorption factor by incorporating prescribed components and a component giving crystals of solid soln. of beta-quartz as principal deposited crystals. CONSTITUTION:Starting material for a glass compsn. contg., by weight, >=94%, in total, of 3.5-5.5% Li2O, 0-2.0% Na2O, 0-2.0% K2O (Na2O+K2O=0.1-2.0%), 20.5-24.0% Al2O3, 60.0-68.5% SiO2, 1.5-3.0% TiO2, 1.0-3.5% ZrO2, 0-4.0% P2O5, 0.08-0.8% Fe2O3 and 0.8-2.0% Nd2O3 is obtd. by blending such oxides so as to satisfy the inequality [where (x) is the amt. (wt.%) of Fe2O3 and (y) is the amt. (wt.%) of Nd2O3], if necessary. Colored low expansion transparent crystallized glass having <=75% visible light transmissivity (Yc) is produced by heat- treating the starting material at 700-900 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-expansion transparent crystallized glass having a very small coefficient of thermal expansion and excellent transparency, and is particularly useful as a window glass for construction or vehicles. It relates to expanded transparent crystallized glass.

[0002]

2. Description of the Related Art Conventionally, as colored glass used for windows of buildings or vehicles, ordinary soda lime glass is colored with Fe2O3, CoO, NiO and Se as colorants.
Glasses of gray, bronze or green, which are obtained by adding at least one of the above, have been widely used.

These glasses are used as heat ray absorbing glasses because they have a calm color tone and have a high infrared absorptivity. However, the high transmittance of ultraviolet rays causes discoloration of printed matters and photographs and deterioration of plastics.

As the colored glass for fire prevention, a corrugated glass in which a metallic mesh is put in the colored soda lime glass has been used, but this is unfavorable from the viewpoint of design and design.

By the way, the colored low expansion transparent crystallized glass has already been used as a top plate of a cooking range, and the technique thereof is disclosed in, for example, Japanese Patent Publication No. 53-38090, Japanese Patent Publication No. 3-9056, and Japanese Patent Laid-Open No. 9056. 63-30
It is disclosed in Japanese Patent No. 3831. However, in the techniques disclosed in the above-mentioned publications, the crystallized glass is dark brown, dark red or black, which is not preferable as a window glass used in buildings or vehicles.

On the other hand, for example, Japanese Patent Publication No. 2-302338 discloses a low expansion transparent crystallized glass having a bronze color tone. However, in the above-mentioned crystallized glass, the Fe2O3 content is 0.005 to 0.
Since it is in the range of 025% by weight, the infrared absorptivity is low, and therefore, there is a problem that the heat ray absorbing ability is poor.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has a color tone such as gray, bronze or green which is preferable as a window glass used for buildings or vehicles. It is an object of the present invention to provide a colored low expansion transparent crystallized glass which has a high infrared absorptivity and a high heat ray absorptivity and a high ultraviolet absorptivity.

[0008]

The present invention, in terms of weight percent, comprises: Li2O 3.5-5.5 Na2O 0-2.0 K2O 0-2.0 Na2O + K2O 0.1-2.0 Al2O3 20.5- 24.0 SiO2 60.0 to 68.5 TiO2 1.5 to 3.0 ZrO2 1.0 to 3.5 P2O5 0 to 4.0 Fe2O3 0.08 to 0.8 Nd2O3 0.8 to 2.0 And the total of the above components is 94% of the total.
% Or more, and the colored low-expansion transparent crystallized glass is characterized by containing β-quartz solid solution crystals as main precipitated crystals.

Also, in terms of weight percent, Li2O 3.5-5.5 Na2O 0-2.0 K2O 0-2.0 Na2O + K2O 0.1-2.0 Al2O3 20.5-24.0 SiO2 60.0- 68.5 TiO2 1.5-3.0 ZrO2 1.0-3.5 P2O5 0-4.0 Fe2O3 0.08-0.8 Nd2O3 0.8-2.0 As2O3 0.05-2.0 MgO 0-2.0 ZnO 0-2.0 CoO 0-0.01 Cr2O3 0-0.05 CuO 0-0.1 NiO 0-0.04, with β-quartz solid solution crystals mainly deposited It is a colored low expansion transparent crystallized glass characterized in that it is contained as crystals.

In the present invention, said Nd2O3 and F
When the weight% of Nd2O3 is y and the weight% of Fe2O3 is x, the e2O3 has a low stimulating purity by adjusting the respective composition ratios so as to satisfy the formula y ≧ 5x−0.7. It is preferable because a crystallized glass having a desired color tone can be obtained.

The optical characteristics in a 5.0 mm thickness measured with a standard light C light in a 2 ° field are visible light transmittance (Yc) of 75% or less, stimulation purity (Pe) of 10% or less, and solar radiation transmittance. (ΤeN) is 75% or less, and 360n
It is preferable that the transmittance of light having a wavelength of m or less is 10% or less.

The crystallized glass of the present invention can be obtained by heat-treating the glass having the above composition in the temperature range of 700 to 900 ° C.

The crystallized glass produced by the above heat treatment has a structure in which fine crystal particles having a particle size of 100 nm or less are uniformly dispersed in the matrix of the glass phase.

The heat treatment for crystallization is suddenly 8
The desired crystallized product can be obtained even by one-step heat treatment of holding at 00 to 900 ° C., but in order to obtain a crystallized glass having a better transmittance, two or more multi-steps are required. It is preferable to perform the heat treatment because the crystal grain size becomes smaller, the decrease in transmittance due to scattering is reduced, and a crystallized product having higher transmittance can be obtained.

The present inventors have studied the absorption ability of various colorants at each wavelength, and as a result, by using Fe2O3, low expansion transparent crystallized glass excellent in absorption ability of ultraviolet rays and infrared rays can be obtained. Found out. However, since the crystallized glass using only Fe2O3 is colored yellow or brown, it is not possible to obtain a preferable color tone as a window glass used for buildings or vehicles.

As a result of further research, Fe2O3 and Nd
By using 2O3 in a limited composition range, it has a preferable color tone as a window glass and has a high ultraviolet absorption rate,
Moreover, it has been found that a colored low expansion transparent crystallized glass having a high infrared absorption capacity can be obtained.

Next, the reasons for limiting the composition range of the crystallized glass of the present invention will be described.

SiO2: When SiO2 exceeds 68.5 wt%, the viscosity of the glass becomes high and it becomes difficult to melt and mold it. Further, it becomes difficult to control crystallization, and the intended crystallized glass cannot be obtained. Also SiO2 is 6
If it is less than 0.0% by weight, the coefficient of thermal expansion becomes small, the cloudiness of the crystallized glass increases, and the transparency decreases. Therefore, the amount of SiO2 is 60.0-68.5 wt%.

Al2O3: 24.0 wt% of Al2O3
If it exceeds, the viscosity of the glass becomes high, and it becomes difficult to melt and mold, and the coefficient of thermal expansion becomes large. Also Al
If the amount of 2O3 is less than 20.5 wt%, the turbidity of the crystallized glass increases and the transparency decreases. Therefore, Al2O3 is set to 20.5 to 24.0 wt%.

Li2O: When Li2O exceeds 5.5 wt%, abrupt crystallization occurs during heat treatment and the desired crystallized glass cannot be obtained. Li2O is 3.5 wt%
When it is less than 1, while the cloudiness increases and the transparency decreases,
It becomes difficult to melt and mold the glass. Therefore, Li2
O is set to 3.5 to 5.5 wt%.

Na2O: Na2O can adjust the coefficient of thermal expansion by improving the solubility of glass and decreasing the crystallinity. However, Na2
When O exceeds 2.0 wt%, the coloring state of Fe2O3 is affected, and not only the stimulus purity becomes too high, but also white turbidity increases and transparency decreases. Therefore, Na2O is set to 0 to 2.0 wt%.

K2O: K2O can adjust the coefficient of thermal expansion by improving the solubility of glass and decreasing the crystallinity. However, K2O is 2.
If it exceeds 0 wt%, it affects the coloring state of Fe2O3,
Not only the stimulus purity becomes too high, but also the cloudiness increases and the transparency decreases. Therefore, K2O is 0-2.0
wt%.

Na2O + K2O: When Na2O + K2O exceeds 2.0% by weight, the stimulus purity becomes high, the cloudiness increases, and the transparency decreases. Na2O + K2O is 0.1
If it is less than wt%, the solubility of the glass tends to decrease, and it is not possible to obtain a crystallized glass having a color tone with low stimulation purity.
Therefore, Na2O + K2O is 0.1 to 2.0%.

TiO2: TiO2 is an essential component as a nucleating agent, but the addition of more than 3.0 wt% does not change the effect of promoting crystallization, and the stimulating purity of the crystallized glass becomes too high. Decrease the transmittance. Also TiO2
Is less than 1.5 wt%, it becomes difficult to dissolve, and the effect of promoting crystallization cannot be sufficiently obtained, and the intended crystallized glass cannot be obtained. Therefore, TiO2 is 1.5 to 3.0
wt%.

ZrO2: ZrO2 is an essential component as a nucleating agent, but if ZrO2 exceeds 3.5 wt%, undissolved substances are likely to be formed and dissolution becomes difficult. Also ZrO
If the content of 2 is less than 1.0 wt%, the effect of promoting crystallization cannot be sufficiently obtained, and white turbidity increases and the desired crystallized glass cannot be obtained. Therefore, ZrO2 is 1.0 to 3.5 wt%
And

Fe2O3: Fe2O3 is an essential component for absorbing ultraviolet rays and infrared rays.
If it exceeds wt%, the stimulus purity becomes too high and the desired color tone cannot be obtained. Fe2O3 is 0.08w
If it is less than t%, the ultraviolet ray and infrared ray absorbing ability becomes insufficient. Therefore, Fe2O3 is 0.08-0.8w
t%.

Nd2O3: Nd2O3 is an essential component for adjusting the transmittance and color tone of glass, but Nd2O3
If O3 exceeds 2.0 wt%, white turbidity increases and transparency decreases. On the other hand, if Nd2O3 is less than 0.8 wt%, the stimulus purity is high and it is not possible to obtain a crystallized glass having a desired color tone. Therefore, Nd2O3 is 0.8
~ 2.0%.

P2O5: P2O5 is a component that promotes the dissolution of ZrO2, but if it exceeds 4.0 wt%, undissolved substances are produced, and white turbidity increases and the transparency decreases. Therefore, P2O5 is set to 0 to 4.0 wt%.

As2O3: As2O3 is effective as a fining agent, but the addition of more than 2.0 wt% does not change the fining promoting effect. If As2O3 is less than 0.05 wt%, a sufficient fining effect cannot be obtained. Therefore, A
s2O3 is 0.05 to 2.0 wt%.

MgO: Even if a small amount of MgO is added, the solubility of glass is improved and the coefficient of thermal expansion is increased. Therefore, if added excessively, the transmittance is lowered, and cracks are easily generated during crystallization.
Since it affects the coloring of e2O3 and the stimulation purity becomes too high, the content is set to 2.0 wt% or less.

ZnO: ZnO is not only effective in improving the solubility of glass, but also lowers the crystallization temperature, reduces the crystal grain size, and improves the transparency. However, if ZnO is added excessively, not only devitrification occurs during glass gradual cooling, it becomes difficult to control the heat treatment, but also the coloring of Fe2O3 is affected, and the stimulating purity becomes too high. Below.

CoO: CoO is also an effective component for adjusting the color tone and transmittance of glass, but if added too much, the stimulation purity becomes too high, so 0.01 wt%
Below.

Cr2O3: Cr2O3 is also an effective component for controlling the color tone and transmittance of glass, but Cr2
If 2O3 is added excessively, the stimulation purity becomes too high, so the content is made 0.005 wt% or less.

CuO: CuO is also an effective component for adjusting the color tone and transmittance of glass, but if CuO is added excessively, the stimulus purity becomes too high, so that
It is 1 wt% or less.

NiO: NiO is also an effective component for adjusting the color tone and transmittance of glass, but if NiO is added excessively, the stimulating purity becomes too high, so that
It should be 04 wt% or less.

Further, the crystallized glass may be added with other trace components within a range that does not impair the properties of the final product.

[0037]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples.

Tables 1 to 3 show the compositions of the crystallized glasses obtained by the examples and comparative examples of the present invention, the heat treatment conditions, and the average coefficients of thermal expansion of the obtained crystallized glasses in the temperature range of 50 to 800 ° C. (Α ₅₀ to ₈₀₀ ), color tone 5.0 mm
Visible light transmittance (Yc), stimulus purity (Pe), dominant wavelength (DW), solar radiation transmittance (τeN), and transmittance at 360 nm as optical characteristics measured in a 2 ° visual field with standard light C light at thickness , And the results of identifying the crystal phase by X-ray diffraction.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

First, the first embodiment will be described. Each glass raw material was prepared so as to have the glass composition shown in Table 1. The prepared glass raw material was put into a platinum crucible, heated and melted at 1550 ° C. using an electric melting furnace, cast into a mold and slowly cooled to obtain a sample glass.

Further, this sample glass was placed in an electric furnace and subjected to a two-step heat treatment of 780 ° C. for 1 hour and 860 ° C. for 1 hour to precipitate fine crystals in the glass. The temperature rising rate at this time was 300 ° C./h, and then the mixture was allowed to cool to room temperature in the furnace.

As a result of measuring the obtained crystallized glass, as shown in Table 1, the stimulus purity is 2.2%, the visible light transmittance is 55.3%, and the solar radiation transmittance is 56.1%, 36.
The transmittance at 0 nm was 1.2%, which had the desired gray color tone. The precipitated crystal phase of the crystallized glass was confirmed to be a β-quartz solid solution by X-ray diffraction, and the thermal expansion coefficient was −5 × 10 ⁻⁷ k ⁻¹ , which was low expansion.

In each of Examples 2 to 8, a sample glass was prepared in the same manner as in Example 1 and crystallized under the two-step heat treatment conditions shown in Table 1 and Table 2, respectively. The obtained crystallized glasses are all transparent and have a visible light transmittance of 75% or less,
Stimulation purity is 10% or less, solar radiation transmittance is 75% or less, 36
The transmittance at 0 nm or less was 10% or less, and the target color tone was obtained. The precipitated crystal phases were all β-quartz solid solutions as in Example 1, and the average coefficient of thermal expansion had a low expansion of 5 × 10 ⁻⁷ k ^{−1 in} absolute value.

Comparative Examples 1 and 2 are commercially available colored soda lime glasses, which have a solar radiation transmittance of 63% or less,
It has a high heat ray absorption capacity but a transmittance of less than 360 nm is 50.
% Or more, the ultraviolet absorption rate was low.

Comparative Examples 3 and 4 are colored low-expansion transparent crystallized glasses in which the composition ratio of each component is outside the scope of the present invention and which is not included in the present invention. Sample glass was prepared in the same manner as in Example 1, and fine crystals were precipitated in the glass under the two-step heat treatment conditions shown in Table 3, respectively. The precipitated crystal phases of the crystallized glasses of Comparative Examples 3 and 4 obtained were β-quartz solid solutions as in the case of Examples, and the average coefficient of thermal expansion was low at an absolute value of 3 × 10 ⁻⁷ k ⁻¹ or less. It was swelling.

Comparative Example 3 is a crystallized glass having a solar radiation transmittance of 16.5%, a transmittance of 360 nm or less of 0%, a very high ultraviolet absorption rate, and a very high heat ray absorption capacity. Because of its high stimulation purity of 89.1%, it was colored dark red.

Comparative Example 4 is a crystallized glass having a transmittance of less than 360 nm of 0.1% and a high UV absorptivity, but has a stimulating purity of 17.3% and is colored dark red. ..

As is clear from the above results, the crystallized glass obtained in the present invention is a crystallized glass having a very small coefficient of thermal expansion and a high transmittance, and having a low excitation purity. ..

[0051]

As described in detail above, according to the present invention, by limiting the material composition and the composition range as described above, it is possible to obtain a preferable gray, bronze or green as a window glass used for buildings or vehicles. It is possible to obtain a colored low expansion transparent crystallized glass having a calm color tone, a high infrared absorption rate and a high heat ray absorption capacity, and a high ultraviolet absorption rate.

Claims (4)

[Claims] 1. Li2O 3.5-5.5 Na2O 0-2.0 K2O 0-2.0 Na2O + K2O 0.1-2.0 Al2O3 20.5-24.0 SiO2 60.0- 68.5 TiO2 1.5 to 3.0 ZrO2 1.0 to 3.5 P2 O5 0 to 4.0 Fe2 O3 0.08 to 0.8 Nd2 O3 0.8 to 2.0 and the above The total of the ingredients is 94
% Or more, and a colored low expansion transparent crystallized glass containing β-quartz solid solution crystals as main precipitated crystals. 2. Li2O 3.5-5.5 Na2O 0-2.0 K2O 0-2.0 Na2O + K2O 0.1-2.0 Al2O3 20.5-24.0 SiO2 60.0- 68.5 TiO2 1.5-3.0 ZrO2 1.0-3.5 P2O5 0-4.0 Fe2O3 0.08-0.8 Nd2O3 0.8-2.0 As2O3 0.05-2.0 MgO 0-2.0 ZnO 0-2.0 CoO 0-0.01 Cr2O3 0-0.05 CuO 0-0.1 NiO 0-0.04, with β-quartz solid solution crystals mainly deposited A colored low-expansion transparent crystallized glass, characterized by containing as crystals. 3. The Nd2O3 and Fe2O3 are Nd2
The colored low expansion transparent crystallized glass according to claim 1 or 2, which satisfies the formula y≥5x-0.7, where y is the weight% of O3 and x is the weight% of Fe2O3. 4. The optical characteristics in terms of 5.0 mm thickness measured with a standard light source C light in a 2 ° field of view are visible light transmittance (Yc) of 75% or less, stimulus purity (Pe) of 10% or less, and solar radiation transmittance. Rate (τeN) is 75% or less, and 360n
The colored low expansion transparent crystallized glass according to claim 1 or 2, which has a transmittance of 10% or less for light having a wavelength of m or less.