JPH06247744A - Marble-like crystallized glass - Google Patents

Abstract

PURPOSE:To provide a marble-like crystallized glass which can be produced in large quantities and a high yield because of excellent stability of the color tone. CONSTITUTION:This marble-like crystallized glass has a compsn. consisting of, by weight, 50-75% SiO2, 1-15% Al2O3, 10-17.5%, in total, of 6-16.5% CaO, 0.1-5% Li2O and 0-1.5% B2O3, 2.5-12% ZnO, 0-12% BaO, 0.1-15% Na2O+K2O and 0-10% colorant and contains beta-wollastonite deposited as principal crystals.

Description

Detailed Description of the Invention

[0001]

The present invention relates to crystallized glass,
In particular, it relates to natural marble-like crystallized glass used for interior and exterior materials of buildings.

[0002]

2. Description of the Related Art Crystallized glass having a natural marble pattern has excellent characteristics such as chemical durability and mechanical strength.
Also, because of its beautiful appearance, it is used as an interior or exterior material for buildings instead of natural stone.

Various types of crystallized glass have been proposed in the past, for example, Japanese Patent Publication No. 51-2396.
No. 6 (US Pat. No. 3,964,917) (hereinafter referred to as Conventional Example I) is 50 to 65 wt% SiO ₂ , 3 to 13 wt% A.
₁₂ O ₃ , 15-25 wt% CaO, and 2-10 w
The crystalline glass composition containing t% ZnO is heat-treated to form β-wollastonite (Ca
A natural marble-like crystallized glass obtained by precipitating O.SiO ₂ ) crystals is disclosed.

[0004] JP-B 53-39884 (hereinafter referred to as conventional example II) is, _45~75wt% SiO 2, _1~13wt%
Al ₂ O ₃ , 6 to 14.5 wt% CaO, but 1 to 1
3 wt% Na ₂ O + K ₂ O, 0-20 wt% BaO and 0-18 wt% ZnO, but 4-24 wt% BaO
A natural marble-like crystallized glass having + ZnO and β-wollastonite crystals as main crystals is disclosed.

Korean Patent Publication 91-9979 (hereinafter referred to as a conventional example)
(Referred to as III) is 55 to 63 wt% SiO ₂ , 5 to 10
A crystalline glass composition having wt% Al ₂ O ₃ , 17 to 22 wt% CaO, and 0.5 to ₃ wt% Li ₂ O is heat-treated to precipitate β-wollastonite crystals in at least a part of its surface layer. Disclosed is a natural marble-like crystallized glass obtained thereby.

Japanese Unexamined Patent Publication (Kokai) No. 3-164446 (hereinafter referred to as Conventional Example IV) discloses 48-68 wt% SiO ₂ , 0.5-17 w.
t% Al ₂ O ₃ , 6-22 wt% CaO, 5-22 wt
% R2O (R: Na, K) 0.2-8 wt% MgO, 0
_{~6wt% B 2 O 3, 0~8wt} % BaO, 0~9wt
% ZnO, provided that BaO + ZnO is 15 wt% or less,
And 0 to 10 wt% colorant, β as the main crystal
-A natural marble-like crystallized glass with wollastonite crystals is disclosed.

[0007]

When heat-treating glass to crystallize it on an industrial scale, large kilns such as shuttle kilns, tunnel kilns and roller hearth kilns are usually used. It is difficult for the firing furnace to have a uniform temperature distribution and a uniform temperature rising / falling rate. For example, in the case of a tunnel kiln, a maximum temperature difference of ± 30 ° C. may occur in the furnace.

However, the known crystallized glasses disclosed in Conventional Example I and Conventional Example II as described above have poor color tone stability under heat treatment conditions, and the amount of crystal precipitation is large if the deviation from the optimum heat treatment conditions is slight. It has a drawback that the color tone changes and becomes unstable, and it becomes difficult to obtain a desired color tone. This tendency is particularly remarkable for crystallized glass that exhibits a dark color tone such as gray or black, and it is difficult to mass-produce it with a large baking furnace in good yield.

Further, the crystallized glass disclosed in Conventional Example III is easily devitrified and does not have a good meltability, so that there is a problem that it is difficult to mold a crystallized glass article. Furthermore, since the amount of crystals is large, there is a problem that a dark colored product cannot be obtained.

Further, the crystallized glass of Conventional Example IV has problems that it is easily devitrified and that the stability of color tone is not good.

An object of the present invention is to provide a dark color tone because it satisfies various conditions required for an exterior material and an interior material, is resistant to devitrification, and is excellent in color tone stability. Another object of the present invention is to provide a natural marble-like crystallized glass which has a good yield and can be manufactured in large quantities.

[0012]

As a result of various researches, the present inventors have found that in order to obtain excellent color stability, the crystallization rate is increased while suppressing the tendency of glass to be pre-transparent. The inventors have found that it is necessary to determine the glass composition so as to have an appropriate amount of crystals, and have proposed the present invention.

That is, the natural marble-like crystallized glass of the present invention comprises SiO ₂ 50 to 75%, Al ₂ O ₃ 1 to 15%, and C.
_{aO6~16.5%, Li 2 O0.1~5%,} B 2 O 3
_{0~1.5%, CaO + Li 2 O} + B 2 O 3 10~1
7.5%, ZnO 2.5-12%, BaO 0-12%,
_{Na 2 O + K 2 O0.1~15%} , has a composition of colorant 0 to 10%, characterized by comprising precipitating β- wollastonite as a main crystal.

[0014]

The reason for limiting the composition range of the present invention will be described below.

The content of SiO ₂ is 50 to 75%, preferably 57 to 70%. When the content of SiO ₂ is more than 75%, the melting temperature of glass becomes high and the viscosity increases, so that the fluidity at the time of heat treatment deteriorates. Further, if it is less than 50%, the devitrification property at the time of molding becomes high, and the precipitation amount of β-wollastonite extremely decreases at the time of heat treatment to lower the mechanical strength.

The content of Al ₂ O ₃ is 1 to 15%, preferably 3 to 10%. If Al ₂ O ₃ is more than 15%, the melting property of the glass is deteriorated and the color stability is deteriorated, and if it is less than 1%, the devitrification is increased and the chemical durability is deteriorated.

CaO, Li ₂ O and B ₂ O ₃ are components closely related to the stability of color tone. That is, in order to obtain excellent color tone stability, it is necessary to accelerate the crystallization rate while suppressing the devitrification tendency of the glass as described above, and to have an appropriate amount of crystals. Is CaO, Li ₂
O within the specific range, and the total amount of the three components obtained by further adding B ₂ O ₃ to these components is 10 to 17.
It is important to limit it to 5%.

CaO is a component that accelerates the crystallization rate and increases the amount of crystals to enhance the stability of color tone, and the content thereof is 6 to 16.5%, preferably 8 to 16%. When CaO is more than 16.5%, devitrification becomes high,
Molding becomes difficult. In addition, the amount of β-wollastonite deposited becomes too large, so that the desired surface smoothness cannot be obtained, and the coloring power of the colorant decreases, making it difficult to obtain a dark color. On the other hand, if it is less than 6%, the amount of β-wollastonite deposited will be small and the stability of the color tone will be reduced, or a natural marble appearance will not be exhibited. In addition, since the mechanical strength is reduced, it cannot be practically used as a building material.

Li ₂ O has the effect of accelerating the crystallization rate, and its content is 0.1-5%, preferably 0.1-3.
%. If the Li ₂ O content is more than 5%, the chemical durability will decrease. On the other hand, if it is less than 0.1%, the meltability and fluidity are deteriorated, and the crystallization speed is slowed down, and the stability of color tone is remarkably lowered.

B ₂ O ₃ is a component added to improve the melting property and fluidity of glass and to accelerate the crystallization rate, and the content thereof is 0 to 1.5%, preferably 0 to 1
%. A small amount of B ₂ O ₃ has the effect of accelerating the crystallization rate, but if it is more than 1.5%, the crystallization rate becomes slower and the color tone stability deteriorates.

In the present invention, CaO, Li ₂ O, B ₂
The total amount of O ₃ is 10 to 17.5%. The reason for limiting the total amount of these three components in this way is as follows. That is, in the composition system of the present invention, all of these components function to reduce the viscosity of the glass, and the greater the amount of these components, the stronger the devitrification tendency. In particular, if the total amount exceeds 17.5%, devitrification becomes remarkable and manufacturing becomes difficult, which is not preferable. On the contrary, as the amount of these components decreases, the devitrification tendency decreases, but if it is less than 10%, the viscosity of the glass becomes too high and the crystallization speed becomes slow, or the amount of crystals becomes insufficient, and the color tone stability becomes remarkably high. Will fall.

The ZnO content is 2.5 to 12%, preferably 2.9 to 9%. Β when ZnO is more than 12%
-Wollastonite is less likely to precipitate and does not have a natural marble-like appearance, and sufficient mechanical strength cannot be obtained. On the other hand, if it is less than 2.5%, the fluidity is remarkably reduced.

The content of BaO is 0 to 12%, preferably 0 to 7%. If BaO is more than 12%, the amount of β-wollastonite deposited will be small, and the stability of color tone and mechanical strength will decrease.

The total amount of Na ₂ O and K ₂ O is 0.1 to 15
%, Preferably 3 to 12%. If the total amount of these components is more than 15%, the chemical durability becomes poor, and 0.1%
If it is less, the viscosity is increased and the meltability and fluidity are deteriorated.

Fe ₂ O ₃ , NiO, Co as colorants
O, MnO ₂ , Cr ₂ O ₃ , CuO and the like can be added up to 10%, but if it exceeds this range, the fluidity is extremely deteriorated during the heat treatment and the raw material cost becomes high, which is not preferable.

The natural marble-like crystallized glass of the present invention contains, in addition to the above-mentioned components, a fining agent such as As ₂ O ₃ and Sb ₂ O ₃ up to 1% in order to improve the meltability of the glass.
In order to stabilize the glass and weaken the devitrification by adding up to 1.5% each of O and SrO, TiO ₂ and Zr.
Components such as O ₂ and P ₂ O ₅ may be contained up to 1% each. The amount of fining agents such as As ₂ O ₃ and Sb ₂ O ₃ is 1%
If it exceeds, it is not preferable in terms of environment. MgO and SrO
If the amount of each of the above exceeds 1.5%, the crystal precipitation is adversely affected and the color tone stability deteriorates. Further, if the amount of TiO ₂ exceeds 1%, the cost becomes high and the color tone of the crystal or glass becomes yellowish. When the amount of ZrO ₂ exceeds 1%, the meltability of glass decreases. If the amount of P ₂ O ₅ exceeds 1%, the glass is likely to undergo phase separation.

Next, a preferred method for producing the natural marble-like crystallized glass of the present invention will be described.

First, glass raw materials prepared so as to have the above-mentioned composition are melted and vitrified, and then glass bodies are produced by a method such as water granulation. Then, the glass small bodies are collected in a fireproof mold and subjected to heat treatment, whereby each glass small body is fused and integrated, and needle-like β-wollastonite from the surface of each glass small body toward the inside. Crystals precipitate,
Crystallization is complete. By polishing the surface of the crystallized glass thus obtained, a crystallized glass exhibiting a natural marble pattern due to the shape of the glass bodies can be obtained.

Inorganic pigments for ceramics such as rutile, spinel, zircon and the like are added in advance to the glass bodies and mixed, and this mixture is accumulated in a mold, or two or more different color tones are used. Natural marble-like crystallized glass having various color patterns can also be obtained by a method of mixing glass bodies with or without mixing them in a mold.

[0030]

EXAMPLES The natural marble-like crystallized glass of the present invention will be described below based on Examples and Comparative Examples.

(Examples) Tables 1 to 4 show examples (Sample Nos. 1 to 15) and comparative examples (Sample No. 16) of the present invention.
~ 19) are shown.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

Each sample was prepared as follows.

Glass raw materials prepared so as to have the composition shown in the table by weight percentage are 5 to 5 at a temperature of 1300 to 1500 ° C.
Melted for 20 hours. The molten glass was put into water, water-granulated, dried and classified to obtain a glass body having a particle size of 1 to 5 mm. Then, the glass bodies are accumulated in a fireproof mold whose inner wall is coated with alumina powder as a release agent, placed in an electric furnace, and heat-treated for 2 hours under the optimum heat-treatment conditions shown in the table (optimum heat-treatment). By holding for 2 hours at the temperature), each glass small body was fused and integrated and crystallized to obtain a sample.

For each of the samples thus obtained,
Sample No. 1 to 10 are white, sample No. 11 and 12
Is beige, and sample No. Sample Nos. 13, 14, 16 to 18 are gray. 15 had a black color. But,
Sample No. No. 19 was not evaluated after crystallization, because devitrified substances were observed at the stage of molding into glass small bodies.

No. When the precipitated crystals of each sample of 1 to 18 were qualitatively analyzed by X-ray diffraction, β-wollastonite was precipitated as a main crystal in all the samples.

When the surface of each sample was polished, a beautiful natural marble pattern appeared in each case with a small amount of polishing.

Next, each of the obtained samples was evaluated for acid resistance, alkali resistance, bending strength, and color stability, and the values are shown in Tables 1 to 4.

Bending strength was measured by a 4-point load method using a sample of 50 × 250 × 17 mm, and the acid resistance and alkali resistance were 25 × in an aqueous solution of 90 ° C., 1% H ₂ SO ₄ and NaOH, respectively. A 25 × 5 mm sample (mirror-polished product) was soaked for 24 hours and evaluated by weight reduction. In addition, the stability of color tone is twice as high as the optimum temperature increase / decrease rate shown in the table (that is, 12
(0 ° C./hour), the sample was prepared by heat-treating at a temperature 20 ° C. lower than the optimum heat treatment temperature, and the color difference (ΔE) from the sample heat-treated under the optimum heat treatment condition was measured using a color difference meter. During the heat treatment, each sample was held at the heat treatment temperatures shown in Tables 1 to 2 for 2 hours.

For comparison, when these characteristics were measured for natural marble, the acid resistance was 34.0 mg /
cm ² , alkali resistance was 3.0 mg / cm ² , and bending strength was 170 kgf / cm ² .

As is apparent from the table, the sample No. which is an example of the present invention. 1 to 15 have an acid resistance of 0.04 to 0.1
3 mg / cm ² , alkali resistance is 0.40 to 0.48 m
g / cm ² , flexural strength 400-500 kgf / cm ²
And was superior to natural marble in all properties. Further, regarding the color tone stability, the color difference is 0.2 to 1.
It was 2.

Sample No. which is a comparative example. 16-18, as is clear from the table, acid resistance 0.08-0.11mg
/ Cm ² , alkali resistance is 0.40 to 0.48 mg / c
The m ² and flexural strength were 400 to 460 kgf / cm ² , which were the same values as in the example. However, the sample N which has a color difference of 2.5 to 3.7 and exhibits the same gray color
o. Compared to 13 and 14, the color difference is 1.8 to 2.1.
Was also great.

Next, an experiment was conducted to evaluate the influence of the presence or absence of Li ₂ O and the heat treatment conditions on the color.

[0047]

[Table 5]

Sample No. according to the invention having the composition shown in Table 5 11 and sample No. 11 as a comparative example. 20 and 21 were manufactured by the same manufacturing method as described above, while changing the heat treatment conditions as shown in Table 5. Each sample had a beige color. Color differences were determined in the same manner as above for the samples with different heat treatment conditions. The results are shown in Table 5.
Shown in.

From Table 5, sample No. of the comparative example containing no Li ₂ O. In 20 and 21, the color difference changes in the range of 2.0 to 4.0 and 2.0 to 4.3 due to the change of the heat treatment condition. On the other hand, the sample N of the embodiment of the present invention
o. In No. 11, it is in the range of 0.9 to 1.2, and the change in color tone due to changes in heat treatment conditions is small, and thus it is clear that the color tone stability is excellent.

[0050]

The natural marble-like crystallized glass of the present invention is
Since it has high chemical durability and mechanical strength, and has a beautiful natural marble pattern, it is suitable as an interior or exterior material for buildings. Moreover, because it has excellent color stability,
Even crystallized glass that exhibits a dark color tone can be mass-produced with good yield.

Claims (5)

[Claims] 1. SiO ₂ 50-75% by weight percentage,
Al ₂ O ₃ 1 to 15%, CaO 6 to 16.5%, Li ₂
O 0.1-5%, B ₂ O ₃ 0-1.5%, CaO + Li
₂ O + B ₂ O ₃ 10-17.5%, ZnO 2.5-12
%, BaO 0 to 12%, Na ₂ O + K ₂ O 0.1 to 15
%, The colorant is 0 to 10%, and β-is used as the main crystal.
Natural marble-like crystallized glass characterized by depositing wollastonite. 2. The natural marble-like crystallized glass according to claim 1, wherein the coloring agent is Fe ₂ O ₃ , NiO, CoO,
Natural marble-like crystallized glass which is at least one of MnO ₂ , Cr ₂ O ₃ and CuO. 3. The natural marble-like crystallized glass according to claim 1, which contains 1% or less of at least 1 of As ₂ O ₃ and Sb ₂ O ₃ as a fining agent. . 4. The natural marble-like crystallized glass according to claim 1, wherein at least one of MgO of 1.5% or less and SrO of 1.5% or less is used to improve the melting property of the glass.
Natural marble-like crystallized glass characterized by containing. 5. The natural marble-like crystallized glass according to claim 1, wherein T is used for stabilizing the glass and weakening devitrification.
Natural marble-like crystallized glass containing at least one of iO ₂ , ZrO ₂ and P ₂ O ₅ in an amount of up to 1%.