JPH0776110B2 - Natural stone-like crystallized glass article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a natural stone-like crystallized glass article suitable for a building material for interior and exterior wall surfaces of a building or a decorative article such as an interior.

[Prior Art] Conventionally, various natural stone-like crystallized glasses have been proposed for inner and outer wall surfaces of buildings. For example, Japanese Patent Publication Sho 53-
As typified by Japanese Patent No. 39884, etc., after accumulating a plurality of granulated glass particles, the glass particles are softened, fused, and integrated with each other by heat treatment, and at the same time, a crystal is formed from the glass grain surface and the fusion interface. There is crystallized glass obtained by precipitation and growth. This crystallized glass is similar in appearance to natural marble, but is characterized by excellent mechanical strength, acid resistance, weather resistance and the like.

Further, as typified by JP-B-60-49145 and JP-A-61-256940, glass synthesized by adding a so-called nucleating agent such as TiO ₂ is roll-out method, press method, pouring method. There is proposed a crystallized glass obtained by molding by a method or the like and heat-treating as it is to crystallize. In this crystallized glass, crystals are deposited almost uniformly over the entire molded product.
As it grows, it gives a uniform and uniform appearance and is considered to have given physical and chemical properties.

Further, as typified by JP-A-59-92942 and JP-A-60-27622, glass containing no so-called nucleating agent is formed into a plate by a roll-out method or the like and crystallized. A marble-like crystallized glass obtained by polishing has also been proposed. This crystallized glass is made of SiO ₂ , A
l ₂ O ₃ , MgO, Na ₂ O as essential ingredients, and forsterite (2Mg
It is characterized by using O.SiO ₂ ) as the main crystal.

[Problems to be Solved by the Invention] A plurality of granulated glass particles of the above-mentioned conventional method are accumulated,
Crystallized glass synthesized by a so-called sintering method in which the glass particles are softened, fused and crystallized by heat treatment is
Since this method is extremely special, there is a problem that the composition range of glass, the kind of precipitated crystals and the physical properties of crystallized glass are limited to a very narrow range. Further, since the granulated glass particles are collected and heat-treated, it is unavoidable that pores remain inside the sintered body. This is due to the appearance of pores exposed on the surface after cutting or polishing the molded product. There are drawbacks such as damage and deterioration of mechanical strength due to pores.

In addition, crystallized glass obtained by molding a glass synthesized by adding a so-called nucleating agent such as TiO ₂ into a plate shape and subjecting it to heat treatment causes crystals to precipitate and grow almost uniformly over the entire molded product. Therefore, the obtained crystallized glass body tends to have a uniform and monotonous appearance, and it is difficult to obtain a natural stone-like appearance.

Furthermore, the crystallized glass obtained by heat-treating glass containing no so-called nucleating agent such as TiO ₂ usually contains an alkali metal oxide such as Na ₂ O in a considerably high proportion of 10 wt% or more, In many cases, the physical properties of the obtained crystallized glass product are adversely affected. For example, there has been a problem that the coefficient of thermal expansion becomes large and the thermal shock resistance and chemical durability are poor.

[Object of the Invention] The present invention improves the above-mentioned drawbacks of the conventional crystallized glass, has physical properties sufficient for use as, for example, architectural and decorative materials, and has a natural stone-like appearance. The object is to provide a new crystallized glass article.

[Means for Solving the Problems] A feature of the crystalline glass article according to the present invention made to achieve the above object is that SiO ₂ 45 to 63, Al ₂ O _{3 5 to} 22, Mg in weight%.
_{O8~30, ZnO1~14, Na 2 O1~9,} K 2 O1~6 ( except Na ₂ O + K ₂ O
Is 2~12), CaO0~12, BaO0~5, containing B ₂ O ₃ 0-5.5, and after forming the glass into a predetermined shape sum of these components is the total 90% or more, the molded article Heat treatment to make forsterite (2MgO ・ SiO ₂ ) one of the main crystals, and in addition to this, garnite (ZnO ・ Al ₂ O ₃ ) or pyroxene-based crystals ((Mg, Ca, Na, Al ) SiO ₃ ) at least one of the crystals is mainly deposited.

The crystallized glass article according to the present invention does not have a uniform and monotonous appearance because it does not contain a so-called nucleating agent such as TiO ₂ , and has a beautiful natural stone-like appearance and Na ₂ O, K ₂ O, etc. Since the alkali metal oxide can be minimized, the thermal expansion coefficient is small, the thermal shock resistance and the chemical durability are excellent, and it is difficult to soften even at a relatively high temperature. Generally, when the content of alkali metal oxide is low,
The melting temperature and viscosity of the glass become high,
Molding becomes difficult, but in the present invention, since an appropriate method was taken for the addition ratio of ZnO and the blending ratio of other components, the meltability of the glass and the alkali metal oxide were minimized without impairing the moldability. The feature is that I was able to finish it.

The reasons why various properties of the crystallized glass according to the present invention in which the alkali metal oxide is minimized as described above are excellent are as follows.

Generally, glass or crystallized glass having a low content of alkali metal oxides contains alkali metal oxides such as Na ₂ O
Compared with the ones that contain a fairly high proportion of wt% or more,
It is known that the coefficient of thermal expansion is small. According to the theory of thermal shock resistance, thermal shock resistance is mainly inversely proportional to the coefficient of thermal expansion (eg Naruse, “Glass Engineering”, (Showa
51.2.5.), Kyoritsu Shuppan, P271). Therefore, it is understood that the material having a small coefficient of thermal expansion has excellent thermal shock resistance. Further, it is known that glass or crystallized glass having a low content of alkali metal oxide has excellent acid resistance as compared with glass having a high content of alkali metal oxide. This is due to the reaction of exchange of hydrogen ions (H ⁺ ) and hydronium ions (H ₃ O ⁺ ) in the acidic solution with the alkali ions on the surface of glass or crystallized glass. It is thought that this is because alkali ions are leached into the solution (for example, “Chemical Society of Japan,“ Inorganic Amorphous Materials ”, (Showa 58.7.10.), Academic Publishing Center, P135).

The reason for limiting the structure of crystals to be precipitated in the crystallized glass in the present invention as described above is as follows. That is, the crystallized glass formed from the material having the raw material composition of the present invention can also precipitate crystals other than the above depending on the heat treatment conditions for crystallization and the like. However, when other crystals are precipitated together with the above crystals, for example, the coefficients of thermal expansion differ relatively greatly between these crystals, and the practical use of this crystallized glass (for example, as a wall material) When used as a building material), the difference in thermal expansion coefficient causes cracks. Therefore, the crystals of the crystallized glass of the present invention are limited to the above types. Strictly speaking, it is not possible to completely suppress the precipitation of a small amount of crystals other than the above, but it is natural that the presence of other crystals of such a quantity and kind that the above does not pose a problem is acceptable.

In the present invention, the reason for limiting the composition of crystallized glass (that is, each component and its mixing ratio) is as follows.

SiO ₂ is a constituent component of precipitated crystals and a glass phase, and if it is 45% or less, vitrification becomes difficult, and at the same time, large pores easily occur inside the crystallized glass obtained by heat treatment.
On the other hand, if the content is 63% or more, the crystal precipitation / growth rate becomes slow, and it becomes difficult to precipitate sufficient crystals.

When Al ₂ O ₃ is 5% or less, fine cracks are easily generated in the crystallized glass obtained by the heat treatment and large pores are easily generated inside the crystallized glass, and when 22% or more, the inside of the crystallized glass obtained by the heat treatment is also easily generated. Large pores are likely to occur.

MgO is a major constituent of precipitated crystals, and if it is 8% or less, it becomes difficult to precipitate sufficient crystals, and at the same time, minute cracks occur in the crystallized glass obtained by heat treatment, and large pores are formed inside the crystallized glass. Are more likely to remain.
On the other hand, if it is 30% or more, devitrification is likely to occur during melting and molding, and vitrification becomes difficult.

ZnO is an essential component as a crystal precipitation / growth promoter,
If it is less than 1%, the crystal precipitation / growth rate will be slow and it will be difficult to deposit sufficient crystals. On the other hand, if it exceeds 14%, the crystal precipitation / growth rate will be too fast, resulting in devitrification during melting / forming. It will be easier.

Alkali metal oxides are essential components added to lower the melting temperature and viscosity of glass.

When Na ₂ O + K ₂ O is less than 2%, the melting temperature and viscosity are high,
While it becomes difficult to melt and shape the glass, if it is 12% or more, desired physical properties such as thermal shock resistance and chemical durability of the crystallized glass obtained by heat treatment cannot be obtained.

Na ₂ O, which is one of the alkali metal oxides, when 1% or less, large pores are likely to be formed inside the crystallized glass obtained by heat treatment, while when it is 9% or more, cracks occur in the crystallized glass, resulting in strength and heat resistance Since desired physical properties such as impact resistance and chemical durability cannot be obtained, the above range of 1 to 9% is preferable, 1 to 7% is most preferable, and 1 to 4% is particularly preferable.

If K ₂ O is in the range other than 1% to 6%, cracks are likely to occur in the crystallized glass obtained by the heat treatment.

CaO is a component preferably added to reduce the viscosity of the glass when it is melted, but if it is 12% or more, fine cracks are likely to occur in the crystallized glass obtained by the heat treatment.

BaO is a component that is preferably added to accelerate the crystallization of glass during heat treatment, but if it is 5% or more, fine cracks are easily generated in the obtained crystallized glass and large pores are formed inside the crystallized glass. Are more likely to remain.

It is preferable to add B ₂ O ₃ as a component effective for lowering the melting temperature of the glass and lowering the viscosity of the glass, but on the other hand, it tends to cause fine cracks in the crystallized glass obtained by the heat treatment, so 5.5% It's best to stick to the following:

In the present invention, the total amount of the above components is required to be 90% or more of the total glass composition, preferably 95% or more, and the balance is an appropriate fining agent that is usually used in the production of glass, and coloring. A general glass composition such as an agent can be added.

For example, Li ₂ O as an effective component for lowering the melting temperature and viscosity, PbO which is a divalent oxide similar to MgO, etc.,
Alternatively, known coloring agents such as CoO, NiO, CuO, Fe ₂ O ₃ , Nd ₂ O
_If necessary, an effective amount of ₃ , MnO ₂ , V ₂ O ₅ , Se or the like, or a known substance having a fluorescent action, such as Eu ₂ O ₃ , Sm ₂ O ₃ or the like may be added. Further, it is preferable to add 1% or less of As ₂ O ₃ , Sb ₂ O ₃ , CeO ₂ or the like as a so-called defoaming and clarifying agent.

The production of the crystallized glass article according to the present invention is generally carried out by subjecting the glass obtained by melting the raw materials prepared in the above composition range to a plate by a conventional forming method such as a roll-out method, a pressing method or a pouring method. Shape, tile shape, etc., and then heat in a heat treatment furnace at a rate of 150 to 500 ° C / hour and hold at 1000 to 1200 ° C for 2 to 6 hours to perform heat treatment. This is done by precipitating crystals from the body surface.

The crystallized glass article according to the present invention can be easily produced by a simple one-step heat treatment after the above-mentioned molding, and as shown in JP-A-61-201631, at least the surface or the surface of the molded body before the heat treatment. A method in which heat is applied after cracking in the vicinity (so-called cracking method),
It is also possible to apply a method (so-called dispersion method) of dispersing a small piece of crystalline glass, crystallized glass, or amorphous glass as described in Japanese Patent Publication No. 62-30630 and then performing heat treatment. Depending on the method, the appearance can be given a characteristic.

[Operation of the Invention] Although the crystallized glass containing a conventional nucleating agent has a relatively large mechanical strength, the crystal grains are small, and the crystal structure is similar to that of the nucleus because the crystal structure grows from the nucleus. While the crystallized glass thus obtained has a generally simple surface pattern and is unlikely to exhibit a natural stone-like decorative appearance, the crystallized glass of the present invention has It is possible to provide a natural stone-like crystallized glass which grows from the surface and interface to form coarse crystal grains and has a deep and decorative appearance due to the orientation of the coarse crystals.

[Examples of the Invention] Examples of the present invention will be described below.

Silica powder, aluminum hydroxide, magnesium oxide, magnesium hydroxide, zinc oxide, potassium carbonate, potassium nitrate, sodium carbonate, sodium nitrate, calcium carbonate, barium carbonate, calcium borate, sodium borate,
Arsenous acid, antimony oxide, and cerium oxide were used as raw materials, and after preparing batches satisfying No. 1 to No. 16 in Table 1, each batch was put into a platinum crucible and melted at a temperature of 1450 ° C for 6 hours in an electric furnace. did. The obtained molten glass is poured into a carbon mold to form a plate of about 300 × 300 × 15 mm, and the plate-shaped glass is transferred onto a fire-resistant plate coated with a release agent powder on the upper surface or the inner surface. Transfer to a fireproof mold coated with release agent powder and heat up to 1050 ℃ in a heat treatment furnace.
The temperature was raised at a rate of 0 ° C./hour, and the heat treatment was performed at 1050 ° C. for 4 hours and 30 minutes.

When the temperature reached about 950 ° C, crystals began to precipitate and grow inward from the surface of the plate-shaped glass, and by continuing the heat treatment, it was possible to obtain a crystallized glass plate which was an aggregate of crystals. Further, when the surface of the obtained crystallized glass plate was polished, a beautiful natural stone-like appearance was obtained. As a result of X-ray diffraction measurement of the crystallized glass obtained by the heat treatment, forsterite and at least one of garnite and pyroxene-based crystals were identified as the main crystals. Specifically, as shown in Table 1, Is. Main crystals F in the table are forsterites, G is garnite, and P is pyroxene-based crystals.

Further, FIG. 1 is a diagram showing the results of powder X-ray diffraction measurement of the crystallized glass of Example No. 6, FIG. 2 is Example No. 14, and FIG. 3 is Example No. 16. F in the figure is forsterite,
G indicates a garnite, and P indicates peaks identified as pyroxene crystals.

The results of measurement of physical properties show that the coefficient of thermal expansion is 60 to 80 × for all the crystallized glass plates obtained from the compositions No. 1 to No. 16 in Table 1.
10 ^-7 / ℃, bending strength 500 ~ 600 kg / cm ² , acid resistance (pH 1 H ₂ SO
_The weight loss ratio after 684 hours in ₄ ) was 0.1 to 0.7%, and it had physical properties sufficient for practical use as a building or decorative material. This means that the coefficient of thermal expansion of natural marble is 100-200 × 10 ^-7 / ℃, bending strength is 100-250 kg / cm.
^2. It is clear when compared with the physical property value of acid resistance of about 100%.

Furthermore, the coefficient of thermal expansion of a conventionally known crystallized glass containing 10 wt% or more of an alkali metal oxide, such as Na ₂ O, was measured and found to be about 100 × 10 ^-7 / ° C or more. Compared with the value of this thermal expansion coefficient, the crystallized glass obtained by the present invention shows a smaller value, and it can be said that it is a more advantageous material in terms of thermal shock resistance.

[Effects of the Invention] The crystallized glass obtained by the present invention has an excellent aesthetic appearance similar to natural stone as described above, and has excellent physical properties that can be sufficiently put into practical use as a building material or a decorative material. Not only is it shown, but since the content of the alkali metal oxide can be minimized, physical properties such as thermal shock resistance based on its thermal expansion coefficient are excellent, and its utility is extremely large.

The provision of such a novel crystallized glass opens up the choice of articles of this kind used in various applications, in particular not only the selection of the respective characteristic decorative appearance that such articles exhibit,
It is preferable because it expands the selection range of the physical properties of various articles.

[Brief description of drawings]

1 is Example No. 6, FIG. 2 is Example No. 14, and FIG. 3 is a diagram showing the results of powder X-ray diffraction measurement of the crystallized glass of Example No. 16. In the figure, F indicates forsterite, G indicates garnite, and P indicates pyroxene-based crystals and fixed peaks.

Claims (1)

[Claims] 1. SiO ₂ 45-63, Al ₂ O ₃ 5-22, MgO 8-
30, ZnO1〜14, Na ₂ O1〜9, K ₂ O1〜6 (however, Na ₂ O ＋ K ₂ O2〜1
2), CaO0~12, BaO0~5, with containing B ₂ O ₃ 0~5.5,
Glass containing substantially no so-called nucleating agent such as TiO ₂ and having a total of 90% or more of these components is molded into a predetermined shape, and then the molded body is heat-treated to be crystallized. A natural stone-like crystallized glass article which comprises forsterite as one of the main crystals and additionally has at least one of garnite and pyroxene-based crystals as the main crystals.