JP5365975B2 - Crystallized glass article and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystallized glass article which improves various characteristics necessary for a decorative material while maintaining thermal shock properties and is capable of imparting high-grade appearance and excellent designability, and a method of manufacturing the same. <P>SOLUTION: The crystallized glass article obtained by integrating crystalline glass small bodies, and heat-treating so as to unify under melt-adhesion and to crystallize is characterized by containing 20-70 wt.% of a Li<SB>2</SB>O-Al<SB>2</SB>O<SB>3</SB>-SiO<SB>2</SB>crystal. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention is a crystallized glass article that can be used as a decoration material such as a glass top plate for a cooker, particularly a glass top plate of a gas stove or a top plate of a kitchen facility, and can impart excellent design properties, and its It relates to a manufacturing method.

  In recent years, as a crystallized glass article used as a decoration material, it has excellent properties such as thermal durability, chemical durability, mechanical strength, etc., and a design that exhibits a new appearance different from natural stone, ceramic plates, and tiles has been pursued. Yes. With such diversification of design properties, decorative materials having various appearances have been developed and proposed.

For example, in Patent Document 1, an inorganic pigment is attached to the interface of a crystalline glass body where crystals precipitate while softening and deforming when heat-treated at a temperature higher than the softening point, and the crystals are fused and integrated by heat treatment. A crystallized glass article is disclosed in which a colored layer appears at the interface of each glass body while being deposited. In addition, Patent Document 2 discloses that glass bodies of different colors of the same material are scattered on the surface of a plate-like crystalline glass where crystals are precipitated while softening and deforming when heat-treated at a temperature higher than the softening point. An integrated crystallized glass with a pattern is disclosed. Further, Patent Document 3 discloses a decorative low expansion crystallized glass plate in which a decorative coating of borosilicate glass frit containing an inorganic coloring pigment is formed on the surface of black low expansion crystallized glass.
JP-A-1-157432 Japanese Patent Laid-Open No. 2-92840 Japanese Patent Laid-Open No. 9-183631

However, the colored crystallized glass disclosed in Patent Document 1 is a so-called surface crystallized glass in which crystals are precipitated from the glass surface. Crystallized glass in which crystals are precipitated while being softened when heat treatment is performed at a temperature above the softening point. In this interface, the inorganic pigment is present in a form covering the crystalline glass, and the surface roughness of the obtained crystallized glass tends to increase, and at the same time, the linear thermal expansion coefficient is 60 × 10 ⁻⁷ / K or more. .

Further, the crystallized crystallized glass article of Patent Document 2 is made of so-called volume crystallized glass in which crystals are precipitated from the inside of the glass, and does not add an inorganic pigment, so that the fluidity of the crystalline glass is reduced during heat treatment. However, the linear thermal expansion coefficient of the obtained crystallized glass is 70 × 10 ⁻⁷ / K or more. Thus, since the crystallized glass articles described in Patent Documents 1 and 2 have a high coefficient of linear thermal expansion, the thermal durability associated with heating, such as the top plate of a gas stove or the top plate of a kitchen, is insufficient. There is a risk of damage.

  The crystallized glass article described in Patent Document 3 has no problem in thermal durability, but it is a decoration by painting, and thus the problem of peeling off of the painted part is likely to occur. Moreover, since the reflectance of the glass surface is low, the brightness as a kitchen appliance is poor and the design is poor.

  As described above, there is a need for a crystallized glass article that has mechanical strength, chemical durability, and thermal durability, and that has a new appearance design that has never been seen before. Therefore, the present invention pays attention to the above circumstances, can improve the characteristics required for various decorative materials while maintaining thermal shock, and can give a high-quality appearance and excellent design. An object of the present invention is to provide a crystallized glass article and a method for producing the same.

  As a result of diligent study, the inventors of the present invention have developed a specific crystal having a large contribution to lowering the linear thermal expansion coefficient in a crystallized glass article obtained by fusing and crystallizing a crystalline glass body by heat treatment. The present inventors have found that the above-mentioned problems can be solved by the inclusion, and propose the present invention.

That is, first, the crystallized glass article of the present invention is to integrate crystalline glass masses, the Rukoto are fused integrally and crystallized by heat treatment, the crystallized glass corpuscles melt together at the interface wear and become _{by, Li 2 O-Al 2 O} 3 -SiO 2 system crystals contain 20-60 weight%, a coefficient of linear thermal expansion 0~30 × ^{10 -7} / K der Rukoto at 30 to 380 ° C. It is characterized by. The crystallized glass article of the present invention has a precipitated crystal amount of Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal of 20 to 60 % by mass by crystallization treatment, and has thermal durability and mechanical strength. In order to have an appearance that does not impair the chemical durability and has surface smoothness and moderate surface glossiness, it is a kitchen equipment decoration material such as a top plate for a cooker, especially a gas stove top plate, a kitchen utensil top plate, a table top, etc. In addition, it is suitable as various other interior / exterior materials. In addition, since each crystalline glass body is fused and integrated with each other at the interface thereof, as described later, a colored layer is provided at each glass body interface, or the glass itself is colored. By doing so, it becomes possible to obtain a crystallized glass article having various appearances and excellent design properties. Here, the linear thermal expansion coefficient in 30-380 degreeC of crystallized glass points out the value measured using the dilatometer.

Second, the crystallized glass article of the present invention is characterized in that the particle size of the crystalline glass body is 0.1 to 20 mm .

  Third, the crystallized glass article of the present invention is characterized in that the glass transition temperature is 600 ° C. or higher. Here, the glass transition temperature of crystallized glass refers to a value measured using a dilatometer.

Fourth, the crystallized glass article of the present invention is characterized by containing a garnite (ZnO.Al ₂ O ₃ ) crystal as a part of the crystal. In the crystallized glass article of the present invention, as described later, it is possible to provide a colored layer at each crystallized glass body interface by attaching a metal oxide powder or an inorganic pigment powder to the crystalline glass body. However, by containing the garnite crystal as a part of the precipitated crystal, the metal oxide powder or the inorganic pigment powder is dissolved in a small amount of precipitated garnite crystal, and the colored layer at the interface of each crystallized glass body Becomes clear and easy to appear, and can be excellent in design.

Fifth, in the crystallized glass article of the present invention, the crystalline glass body has a mass% of SiO ₂ 55 to 72%, Ai ₂ O ₃ 14 to 30%, Li ₂ O 1.5 to 5%, K ₂ O 1-10%, TiO ₂ 0-5%, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 0-7%, ZnO 0-10%, MgO 0-2.5%, CaO 0-2. It contains 5%, BaO 0-8%, B ₂ O ₃ 0-7%, Na ₂ O 0-2%, P ₂ O ₅ 0-0.8%. The crystalline glass body having the composition has fluidity that can be fused and integrated with each other, and is Li ₂ O—Al ₂ O ₃ —SiO ₂ type such as β-quartz solid solution or β-spodumene solid solution. Since the crystals are precipitated as main crystals, it becomes possible to obtain a low expansion crystallized glass by firing, which has high heat resistance and is easy to be thinned. In addition, since this crystalline glass body is subjected to heat treatment, crystals are precipitated from the inside of the glass body, so that the surface smoothness is improved as compared with the crystalline glass in which crystals are deposited from the surface. There are few bubbles that are likely to occur at the interface of the body. Furthermore, as described above, by depositing a small amount of garnite crystal as a crystal, the metal oxide powder or inorganic pigment powder is dissolved in the garnite crystal, and only the surface of each crystallized glass body is colored to give a colored pattern. It can appear clearly.

Sixth, in the crystallized glass article of the present invention, the crystalline glass body has a mass% of SiO ₂ 55 to 72%, Ai ₂ O ₃ 14 to 30%, Li ₂ O 1.5 to 5%, K ₂ O 1-10%, TiO ₂ 1-5%, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 2.5-7%, ZnO 0-10%, MgO 0-2.5%, CaO 0 _{2.5%, BaO 0~3%, B} 2 O 3 0~7%, Na 2 O 0~2%, characterized by containing the composition of P 2 O 5 0~0.8%.

  Seventh, the crystallized glass article of the present invention uses a crystalline glass body obtained by adhering 3 parts by mass or less of metal oxide powder or inorganic pigment powder to 100 parts by mass of crystalline glass body. The present invention is characterized in that a colored layer made of a metal oxide powder or an inorganic pigment powder appears at the interface of each fused crystallized glass body. In a crystallized glass article obtained by attaching a metal oxide powder or inorganic pigment powder to the surface of a crystalline glass body and fusing and integrating them by heat treatment, the metal oxide powder or A colored layer made of an inorganic pigment powder can be revealed, and a mesh pattern excellent in design can be exhibited.

  Eighth, the crystallized glass article of the present invention is such that at least a part of the crystalline glass body contains a colored component in an amount of 5% by mass or less, thereby providing a colored crystallized glass part. Features. Thus, by including a coloring component in the crystalline glass composition, a crystallized glass article based on colored glass can be obtained. In particular, by using a mixture of a crystalline glass body containing a coloring component and a crystalline glass containing no coloring component in the composition, it becomes possible to exhibit a spotted pattern in which a colored portion and a non-colored portion are mixed.

Ninthly , the crystallized glass article of the present invention is characterized in that it is used for a cooking appliance top plate or a kitchen equipment decoration material.

Tenth , the present invention relates to a method for producing a crystallized glass article according to any one of the above, wherein the crystalline glass bodies are accumulated in a refractory mold, and the softening point of the crystalline glass bodies is exceeded. It is characterized by heat treatment at a temperature for fusion integration and crystallization.

The crystallized glass article of the present invention is obtained by accumulating crystalline glass bodies, fused and integrated by heat treatment, and crystallizing a specific amount of Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystals. It will be.

In the crystallized glass article of the present invention, the content of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal is 20 to 70% by mass, and preferably 30 to 60% by mass. When the crystal content is less than 20% by mass, the linear thermal expansion coefficient of the obtained crystallized glass article tends to increase, and the heat resistance targeted by the present invention cannot be obtained. On the other hand, if the content of precipitation exceeds 70% by mass, the firing temperature of the crystalline glass body tends to be high, for example, 1300 ° C. or higher, and is not suitable for a normal firing furnace, and a smooth plate-like product cannot be obtained. Problems are likely to occur. Further, as will be described later, softening due to reheating hardly occurs, and softening processing such as bending tends to be difficult.

The linear thermal expansion coefficient of the crystallized glass article of the present invention is preferably 30 × 10 ⁻⁷ / K or less, and more preferably 20 × 10 ⁻⁷ / K or less. For example, in the gas range glass top, the temperature of the burner port that is the highest temperature due to the influence of the gas flame is 200 ° C. or higher. For this reason, tensile stress is generated on the outer periphery of the low temperature glass top plate away from the burner port, leading to breakage. When the linear thermal expansion coefficient of the crystallized glass article is larger than 30 × 10 ⁻⁷ / K, the generated stress becomes about 30 MPa or more and the probability of breakage increases. By making the coefficient of linear thermal expansion of the crystallized glass article smaller than 30 × 10 ⁻⁷ / K, the stress generated on the outer periphery of the glass top plate becomes less than the fracture allowable stress of the crystallized glass article and is not easily damaged by heat. Become. The lower limit is not particularly limited, but if it is too low, the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal amount becomes excessive and tends to inhibit the flow of the glass, so that in reality it is 0 × 10. ^-7 / K or more, more preferably 5 × 10 ^-7 / K or more.

  The glass transition temperature of the crystallized glass article of the present invention is preferably 600 ° C. or higher, more preferably 620 ° C. or higher. If the glass transition temperature is less than 600 ° C., the viscosity of the glass phase becomes too low, foaming after heat treatment tends to occur, and control of the heat treatment temperature tends to be difficult. The upper limit is not particularly limited, but considering the necessity of bending, it is preferably 800 ° C. or lower, more preferably 700 ° C. or lower.

By the way, the crystallized glass article of the present invention is composed of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal and residual matrix glass, but a crystal in which the difference between the average linear thermal expansion coefficients of both is larger than a predetermined value. The difference in the average linear thermal expansion coefficient at 30 to 380 ° C. between the vitrified glass, specifically, the matrix glass and the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal is preferably 35 × 10 ⁻⁷ / K or more. . In the accumulation method, it is necessary to soften and flow the crystalline glass body, and thus it is necessary to reduce the amount of crystals. However, reducing the amount of crystals tends to increase the linear thermal expansion coefficient of the crystallized glass article. Therefore, by increasing the difference in the average linear thermal expansion coefficient between the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal and the matrix glass from a predetermined value, as will be described later, the linear thermal expansion coefficient lower than the theoretical value is set. It can be set as the crystallized glass article which has. In addition, the crystallized glass article can be easily softened by reheating, and can be bent into a desired shape. The mechanism showing such characteristics is explained as follows.

It is known that Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystals have anisotropic thermal expansion characteristics, that is, the linear thermal expansion coefficient varies depending on the crystal axis. Therefore, in the crystallized glass containing Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal, in the cooling process of the crystallization treatment, the negative expansion axis side of the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal and Shear stress is generated at the interface with the matrix glass having positive expansion. Along with that, voids are generated at the interface between the Li ₂ O—Al ₂ O ₃ —SiO ₂ crystal and the matrix glass. The void reduces the positive expansion contribution of the matrix glass and the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal in the crystallized glass, and the negative expansion axis of the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal. The contribution of is emphasized. This effect is more effective when the difference in average linear thermal expansion coefficient between the matrix glass and the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal is larger (or the average linear thermal expansion coefficient of the matrix glass and Li ₂ O—Al ₂ O _The greater the difference in the coefficient of thermal expansion of the negative expansion axis of the ₃ -SiO ₂ crystal, the more significant it is.

In general, the linear thermal expansion coefficient of crystallized glass is additively determined by the average linear thermal expansion coefficient and volume fraction of each of crystal and matrix glass, but Li ₂ O—Al ₂ O ₃ —SiO _2. It is possible to obtain a crystallized glass having a linear thermal expansion coefficient lower than the linear thermal expansion coefficient predicted from the additivity rule by making the difference in the average linear thermal expansion coefficient between the system crystal and the matrix glass larger than a predetermined value. It becomes possible.

Specifically, in the crystallized glass article of the present invention, the difference in average linear thermal expansion coefficient at 30 to 380 ° C. between the matrix glass and the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal is preferably 35 × 10. ⁻⁷ / K or more, more preferably 40 × 10 ⁻⁷ / K or more, and further preferably 50 × 10 ⁻⁷ / K or more. When the difference in the average linear thermal expansion coefficient is less than 35 × 10 ⁻⁷ / K, the stress generated at the interface between the matrix glass and the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal particles is too small. It becomes difficult to form voids. As a result, the linear thermal expansion coefficient of the crystallized glass article is unlikely to decrease. The upper limit is not particularly limited, but if the difference in average linear thermal expansion coefficient between the matrix glass and the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal is too large, damage due to heat tends to occur. Since it tends to generate cracks at the interface between the crystal particles and the matrix glass and the mechanical strength of the crystallized glass article tends to decrease, it is preferably 70 × 10 ⁻⁷ / K or less in practice.

In the crystallized glass article of the present invention, the average linear thermal expansion coefficient at 30 to 380 ° C. of the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal is preferably −80 × 10 ⁻⁷ to 15 × 10 ^{−. 7} / K, more preferably −50 to 5 × 10 ⁻⁷ / K. _Here, the average linear thermal expansion coefficient of the _{Li 2 O-Al 2 O 3} -SiO 2 based crystal is calculated by dividing the volume expansion coefficient of the _{Li 2 O-Al 2 O 3} -SiO 2 based crystal 3 Is done. When the average linear thermal expansion coefficient of the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal is less than −80 × 10 ⁻⁷ / K, the stress generated at the interface between the crystal particles and the matrix glass becomes too large, Cracks are likely to occur at the interface, and as a result, the mechanical strength of the crystallized glass article tends to decrease. On the other hand, when the average linear thermal expansion coefficient of the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal exceeds 15 × 10 ⁻⁷ / K, the stress generated at the interface between the crystal particles and the matrix glass is too small. As a result, the linear thermal expansion coefficient of the crystallized glass article is hardly lowered.

In the crystallized glass article of the present invention, the average particle size of the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal particles is preferably 1 μm or more, more preferably 5 μm or more. When the average particle size of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal particles is less than 1 μm, the influence of stress generated at the interface between the crystal particles and the matrix glass is reduced, and voids are formed at the interface between the crystal particles and the matrix glass. Tends to be difficult to form. Therefore, the linear thermal expansion coefficient of crystallized glass is unlikely to decrease. The upper limit is not particularly limited, but if the average particle size of the Li ₂ O—Al ₂ O ₃ —SiO ₂ crystal particles is too large, cracks are likely to occur at the interface between the crystal particles and the matrix glass, and the crystal Since the mechanical strength of the vitrified glass article tends to decrease, it is preferably 300 μm or less in practice.

  The yield temperature of the crystallized glass article of the present invention is preferably 850 ° C. or lower, more preferably 800 ° C. or lower. When the yield temperature of the crystallized glass article exceeds 850 ° C., softening due to reheating becomes difficult to occur, so that the accuracy of softening processing such as bending processing tends to be lowered. Here, the yield temperature of the crystallized glass refers to a value measured using a dilatometer.

As described above, by containing a garnite crystal as a part of the precipitated crystal in the crystallized glass article, the metal oxide powder or inorganic pigment powder used as the colored layer can be dissolved in a garnite crystal that precipitates in a small amount. . The content of garnite crystals in the crystallized glass article is preferably 1% by mass or more, and more preferably 2% by mass or more in order to make the colored layer appear clearly. However, if excessive precipitation occurs, precipitation of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystals is suppressed, and the linear thermal expansion coefficient of the crystallized glass article tends to increase. Preferably, it is 5 mass% or less, More preferably, it is 4 mass%.

The crystalline glass body in the present invention has fluidity that can be fused and integrated with each other by heat treatment, and precipitates as a main crystal of β-quartz solid solution or β-spodumene solid solution Li ₂ O—Al ₂ O _3. —SiO ₂ crystalline glass is preferred. Hereinafter, this type of crystalline glass will be described.

In the case of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystalline glass, in order to obtain the above-mentioned characteristics, by mass%, SiO ₂ 55 to 72%, Al ₂ O ₃ 14 to 30%, Li ₂ O _{1.5~5%, K 2 O 1~10%} , TiO 2 0~5%, ZrO 2 0~4%, TiO 2 + ZrO 2 0~7%, 0~10% ZnO, MgO 0~2.5 %, CaO 0-2.5%, BaO 0-8%, B ₂ O ₃ 0-7%, Na ₂ O 0-2%, P ₂ O ₅ 0-0.8% It is preferable to use it.

It is more preferred composition, in _{mass%, SiO 2 55~72%, Al} 2 O 3 14~30%, Li 2 O 1.5~5%, K 2 O 1~10%, TiO 2 1~5 %, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 2.5-7%, ZnO 0-10%, MgO 0-2.5%, CaO 0-2.5%, BaO 0-3%, B ₂ O ₃ 0-7%, Na ₂ O 0-2%, P ₂ O ₅ 0-0.8%.

  The reason for limiting the content of each component in this way is as follows.

SiO ₂ is a main component of glass and a crystal component, and its content is preferably 55 to 72%, more preferably 60 to 70%. When the content of SiO ₂ is less than 55%, crystal precipitation becomes unstable. On the other hand, when the content of SiO ₂ is more than 72%, the softening point of the crystallized glass is increased and the fluidity is lowered, and the meltability at the time of melting the glass is deteriorated, making it difficult to form the glass. Moreover, there exists a tendency for the softening process by reheating to become difficult. Furthermore, the linear thermal expansion coefficient of the matrix glass decreases, the difference from the average linear thermal expansion coefficient of the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal becomes small, and the stress generated at the interface between the two is too small. It becomes difficult to form voids. As a result, the linear thermal expansion coefficient of crystallized glass is unlikely to decrease.

Al ₂ O _{3 is} also a crystal component, and the content thereof is preferably 14 to 30%, more preferably 16 to 25%. When the content of Al ₂ O ₃ is less than 14%, the crystals are coarsened, and the surface smoothness of the resulting crystallized glass article tends to deteriorate, or the mechanical strength of the crystallized glass article tends to decrease. On the other hand, when the content of Al ₂ O ₃ is more than 30%, not only the meltability of the glass is lowered, but also the liquidus temperature becomes too high and devitrification is likely to occur during glass forming.

Li ₂ O is essential as a constituent component of the crystal, and its content is preferably 1.5 to 5%, more preferably 1.8 to 3.5%. When the content of Li ₂ O is less than 1.5%, it is difficult to obtain a uniform Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal, which tends to be unstable as crystallized glass. On the other hand, when the content of Li ₂ O exceeds 5%, the crystallinity becomes too strong and the fluidity is lowered, and the smoothness of the resulting crystallized glass article is difficult to obtain. In addition, the crystallinity becomes so high that the crystallized glass article is not easily softened by reheating, and softening such as bending tends to be difficult.

K ₂ O is an essential component for controlling crystallinity, and adjusts the softening point by adjusting the ratio of the glass phase, thereby affecting the fluidity. The content of K ₂ O is preferably 1 to 10%, and more preferably 2 to 7%. When the content of K ₂ O is less than 1%, the crystallinity becomes too strong and the fluidity tends to deteriorate. In addition, the crystallinity of the crystallized glass article becomes too high, and the softening workability due to reheating tends to deteriorate. On the other hand, when the content of K ₂ O exceeds 10%, precipitation of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystals is suppressed, and thus it becomes difficult to form crystallized glass.

TiO ₂ and ZrO ₂ are substances that become nuclei during Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal precipitation, and have the effect of finely precipitating crystals and the effect of stable crystal precipitation. When either or both of TiO ₂ and ZrO ₂ are added to the crystalline glass, a rutile crystal (TiO ₂ ), a zirconia crystal (ZrO ₂ ), or a Li ₂ O—Al ₂ O ₃ —SiO ₂ system crystal, or Zirconium titanate crystals (ZrTiO ₄ ) are precipitated. Since these crystals have a higher refractive index than Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystals and matrix glass, they can be made into a crystallized glass article with high whiteness. The content of TiO ₂ is preferably 0 to 5%, more preferably 1 to 4, and further preferably 1.5 to 4%. The content of ZrO ₂ is preferably 0 to 4%, and more preferably 1 to 2.5%. Moreover, it is preferable that both total content is 0 to 7%, and it is more preferable that it is 2.5 to 7%. If the total of both exceeds 7% or exceeds the upper limit of the above range alone, the crystallization speed becomes too fast and the glass tends to devitrify, and the fluidity tends to be hindered during crystallization. In addition, when the total of both is less than 2.5%, it will become difficult to precipitate a dense crystal stably. On the other hand, when TiO ₂ and ZrO ₂ are not contained, since the high refractive index crystal is not precipitated, a crystallized glass article having translucency can be obtained.

ZnO is a constituent component of garnite crystals. When ZnO is added to crystalline glass, garnite crystals (ZnAl ₂ O ₄ ) are precipitated together with Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystals. Since garnite crystals have a higher refractive index than Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystals and matrix glass, crystallized glass with high whiteness can be obtained. Further, by providing a layer made of a metal oxide powder or inorganic pigment powder that can be dissolved in garnite crystals on the glass surface, a vivid colored crystallized glass can be obtained. The content of ZnO is preferably 0 to 10%, more preferably 1 to 10%, still more preferably 2 to 6%. If the ZnO content is more than 10%, the precipitation of garnite crystals will increase so that the main crystal, Li ₂ O—Al ₂ O ₃ —SiO ₂ crystal, will be difficult to precipitate, and linear thermal expansion after crystallization will occur. The coefficient tends to increase. On the other hand, in order to precipitate garnite crystals and obtain a coloring effect, the content of ZnO is preferably 1% or more, more preferably 2% or more. Note that when ZnO is not added, a garnite crystal does not precipitate, so that a crystallized glass having translucency can be obtained.

MgO, CaO, BaO, B ₂ O ₃ and Na ₂ O are all effective components for lowering the softening point of the crystalline glass. However, if the above range is exceeded, it becomes difficult to deposit desired crystals. In addition, in order to acquire the said effect, it is preferable to contain 1% or more of at least 1 sort (s) among these components.

P ₂ O ₅ has an effect of making the crystal finer, but when it exceeds 0.8%, devitrification becomes strong. Although a minimum is not specifically limited, In order to acquire the said effect, containing 0.1% or more is preferable.

In addition, SnO ₂ can be added as a clarifier in an amount of 0 to 1%, preferably 0.1 to 0.5%. In addition, As ₂ O ₃ and Sb ₂ O ₃ can be added as other clarifiers in a range where the total amount of the clarifier does not exceed 5%.

The crystallized glass article of the present invention obtained by fusing and integrating the crystalline glass bodies by heat treatment is SiO ₂ 55 to 72%, Al ₂ O ₃ 14 to 30%, Li ₂ O in mass%. _{1.5~5%, K 2 O 1~10%} , TiO 2 0~5%, ZrO 2 0~4%, TiO 2 + ZrO 2 0~7%, 0~10% ZnO, MgO 0~2.5 %, CaO 0-2.5%, BaO 0-8%, B ₂ O ₃ 0-7%, Na ₂ O 0-2%, P ₂ O ₅ 0-0.8%. preferable. The reason for limiting the ratio of each component in this way is the same as described above.

More preferred composition, in _{mass%, SiO 2 55~72%, Al} 2 O 3 14~30%, Li 2 O 1.5~5%, K 2 O 1~10%, TiO 2 1~5%, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 2.5-7%, ZnO 0-10%, MgO 0-2.5%, CaO 0-2.5%, BaO 0-3%, B ₂ O ₃ It is represented by 0 to 7%, Na ₂ O 0 to 2%, and P ₂ O ₅ 0 to 0.8%.

  In the crystallized glass article of the present invention, the addition amount of the metal oxide powder or inorganic pigment powder used to reveal the colored layer is 3 parts by mass or less with respect to 100 parts by mass of the crystalline glass body. It is preferably 1 part by mass or less. If the added amount of the metal oxide powder or inorganic pigment powder exceeds 3 parts by mass, the flow of the crystalline glass bodies is hindered, the fusion of the crystalline glass bodies becomes insufficient, and bubbles remain, as a result. The strength of the resulting crystallized glass article tends to be inferior. Moreover, the surface roughness of the crystallized glass article obtained tends to increase. Although it does not specifically limit about a minimum, In order to make a clear colored layer appear, it is preferable to set it as 0.01 mass part or more, and it is more preferable to set it as 0.05 mass part or more.

  As the metal oxide powder, cobalt oxide, nickel oxide, iron oxide, vanadium oxide or the like is used. By adhering to a small amount of garnite crystals, cobalt oxide develops blue color, nickel oxide green, iron oxide brown, and vanadium oxide yellowish brown.

  Examples of inorganic pigment powders include zircon pigments such as Zr-Si-Fe (light reddish brown), Zr-Si-Pr (light yellow), Zr-Si-V (light blue), Zn-Cr-Ni-Al (brown Color), spinel pigments such as Al-Co-Zn (blue), Fe-Cr-Zn (dark brown).

  These metal oxide powders and inorganic pigment powders may be used alone or in combination of two or more.

  In the crystallized glass article of the present invention, the content of the coloring component used for coloring the crystalline glass body is preferably 5% by mass or less, preferably 1% by mass or less in the crystalline glass composition. It is more preferable. When the content of the coloring component exceeds 5% by mass, the degree of coloring of the crystallized glass article to be obtained becomes too strong, and the content of other components in the glass composition, which impairs the texture, is relatively reduced. There is a tendency that problems such as an influence on each physical property of the crystallized glass article and an increase in the coefficient of linear thermal expansion due to a decrease in the amount of crystals are caused. The lower limit is not particularly limited, but is preferably 0.01% by mass or more in order to obtain a sufficient coloring effect.

  As the coloring component, cobalt oxide, nickel oxide, iron oxide, vanadium oxide, or the like is used. These may be used alone or in combination of two or more.

  In addition, when mixing and using the crystalline glass body containing a coloring component and the crystalline glass which does not contain a coloring component in the composition, the mixing ratio is not specifically limited, According to the pattern of the target crystallized glass article May be selected as appropriate. For example, the ratio of (crystalline glass body containing coloring component in composition) :( crystalline glass body not containing coloring component in composition) is preferably 5:95 to 95: 5, 10: It is more preferably 90 to 90:10, and further preferably 30:70 to 70:30.

As another form, the crystallized glass article of the present invention is obtained by accumulating glass bodies and fusing and integrating them by heat treatment, and the linear thermal expansion coefficient at 30 to 380 ° C. is 30 × 10 ⁻⁷ / K or less. It is characterized by being. The reason why the linear thermal expansion coefficient is set to 30 × 10 ⁻⁷ / K or less and the preferable range are the same as described above. The lower limit is not particularly limited, but if it is too low, the amount of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal becomes excessive and tends to inhibit the flow of glass. 10 ⁻⁷ / K or more, and further 5 × 10 ⁻⁷ / K or more.

  Next, the manufacturing method of the crystallized glass article of this invention is demonstrated.

  In the method for producing a crystallized glass article according to the present invention, crystalline glass bodies are accumulated in a fireproof mold, and heat treatment is performed at a temperature equal to or higher than the softening point of the crystalline glass bodies to fuse and integrate and crystallize. It is characterized by that. Here, as the crystalline glass body, a glass body on which crystals have already partially precipitated may be used. Also, after mixing and adhering the metal oxide powder or inorganic pigment powder to the crystalline glass body, and then accumulating it in the refractory mold, in the resulting crystallized glass article, at each crystallized glass body interface It becomes possible to make the colored layer appear.

  As a method for producing a crystalline glass body, glass that has been melted by pouring molten glass into water and pulverized (water-granulated) by thermal shock, or glass that has been formed into a plate shape (for example, 5 mm or less in thickness) is made of alumina or the like. The method of classifying with a sieve after pulverizing with a mill is mentioned.

  The particle size and shape of the obtained crystalline glass body are not particularly limited, and a pattern according to it can be obtained by selecting arbitrarily. However, for the following reasons, the particle size of the crystalline glass body is preferably 0.1 to 20 mm, more preferably 0.5 to 10 mm, and further preferably 0.5 to 5 mm. . When the particle size of the crystalline glass body is smaller than 0.1 mm, there is a problem in workability and it becomes difficult to make a pattern. On the other hand, when the particle size of the crystalline glass body is larger than 20 mm, mixing with the metal oxide powder or the inorganic pigment powder becomes difficult, and coloring tends to be insufficient.

  Mixing of the crystalline glass and the metal oxide powder or the inorganic pigment powder can be performed by a known method such as a V-type mixer or a concrete mixer. A binder such as polyvinyl alcohol may be added as appropriate.

  The material of the refractory mold used for firing is not particularly limited as long as it has heat resistance equal to or higher than the firing temperature, and examples thereof include mullite cordierite, gypsum mold, and SiC. .

  In addition, it is preferable that a refractory form is equipped with mold release materials, such as a ceramic fiber sheet and an alumina sheet.

Since the crystallized glass article of the present invention is mainly used for a glass top plate of a gas range, a top plate of a kitchen facility, etc., surface smoothness is required. From such a viewpoint, the firing temperature is higher than the softening point of the crystalline glass body, preferably the viscosity of the glass is 10 ^4.5 to 10 ^5.5 poise (that is, 10 ^4.5 to 10 ^5.5 dPa · s). s). Specifically, although it depends on the type of crystalline glass, the firing temperature is preferably 1100 ° C. or higher, more preferably 1200 ° C. or higher. In consideration of the limitation of the firing kiln and the fuel cost, the firing temperature is preferably 1300 ° C. or lower.

Then, preferably by cooling at a rate of 200 ° C. or less per hour, more preferably 150 ° C. or less per hour, the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal is 20 to 70 as the total amount of precipitated crystals. It is possible to obtain a crystallized glass containing garnite crystals, preferably 5% by mass or less. When the cooling rate is higher than 200 ° C. per hour, crystal precipitation is not stable, and as a result, the value of the linear thermal expansion coefficient of the obtained crystallized glass article tends to be unstable.

Example 1
(A) Production of crystalline glass article A glass raw material prepared to have the composition shown in Table 1 was melted at 1650 ° C. for 12 hours, and this molten glass was poured into water to obtain a crystalline glass body. When the linear thermal expansion coefficient of this crystalline glass was measured by the DILATO method, it was 40 × 10 ⁻⁷ / K and the transition temperature was 680 ° C. Regarding the viscosity, the temperature at the viscosity of 10 ^4.5 and 10 ^5.5 poise was measured with a parallel plate viscometer, and it was 1280 ° C. for 10 ^4.5 poise and 1080 ° C. for 10 ^5.5 poise.

  The obtained crystalline glass body was classified with a sieve to a particle size of 1.0 to 5 mm to obtain a grainy crystalline glass body. To 100 parts by mass of this crystalline glass body, 0.1 part by mass of cobalt oxide powder, which is a metal oxide, was mixed and mixed lightly, and after adding a small amount of polyvinyl alcohol as a binder, it was mixed well. Next, a mold having an inner dimension of 450 mm × 650 mm × depth 20 mm was prepared by coating alumina powder on a mullite cordierite shelf plate laid with alumina sheets, and the cobalt oxide powder obtained above was 5.6 kg of crystalline glass particles adhering to the surface were evenly accumulated. This is an amount such that the thickness of the crystallized glass plate obtained after the heat treatment is about 7 mm. Then, it baked with the shuttle kiln (gas furnace) in this state. As firing conditions, the temperature was raised at a rate of 100 ° C. per hour, held at 1250 ° C. for 1 hour, then cooled to 700 ° C. at a rate of 100 ° C. per hour, and then furnace-cooled to obtain a fired body, A crystallized glass article was obtained. The obtained crystallized glass article had a blue color at the interface of the glass body, and the polished surface had a mesh pattern having a blue layer at the interface of the glass body.

In order to confirm the amount of crystals of the obtained crystallized glass article, a part of the crystalline glass body is accumulated in a refractory container, and then crystallized glass is produced under the same firing conditions and cooling conditions as described above. Then, the crystallized glass was measured for the amount of crystal precipitation by a multiple peak separation method using an X-ray diffractometer manufactured by Rigaku. As a result, it was confirmed that 45% by mass of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based β-quartz solid solution and 4% by mass of garnite crystals were precipitated.

(B) Measurement of physical properties of crystallized glass article The linear thermal expansion coefficient and glass transition temperature of the obtained crystallized glass article were measured with a dilatometer manufactured by Bruker AXS.

  For the heat resistance test, standard equipment is fixed to each specimen using a Herman gas built-in stove (110-H551 type), and a gas frame is put on a 250 mm sized pan at full power with a high-calorie burner. When heated for 30 minutes, those that were not damaged passed and those that were damaged were rejected. The maximum temperature of the crystallized glass article at that time was about 230 ° C. Further, the stress generated at that time was obtained by performing a radiant heat transfer analysis by simulation using analysis software (ANSY: structural analysis).

  About bending strength, it carried out by 4-point bending strength according to ASTM C880-78.

  The results are shown in Table 1.

(Example 2)
Crystalline glass bodies similar to those in Example 1 were pulverized with an alumina ball mill, and then classified with a sieve to a particle size of 0.5 to 2.0 mm to obtain fine grained crystalline glass bodies. After mixing 0.3 parts by mass of Si-Zr-Fe-based inorganic pigment powder in the same manner as in Example 1 with respect to 100 parts by mass of this crystalline glass body, crystallized glass under the same firing and cooling conditions. An article was obtained. The obtained crystallized glass article had a light reddish brown color at the interface of the glass body, and the polished surface had a mesh pattern having a light reddish brown layer at the interface of the glass body.

  The physical properties of the obtained crystallized glass article were measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
The crystalline glass bodies similar to Example 1 were accumulated and fired in the same manner as in Example 1 without adding inorganic pigment powder to obtain a white crystallized glass article having no pattern. Note that, on the polished surface of the obtained crystallized glass article, it was observed that the crystallized glass bodies were fused to each other at the interface.

  The physical properties of the obtained crystallized glass article were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 4
As shown in Table 1, a dark blue crystalline glass body was obtained in the same manner as in Example 1 using a glass raw material prepared so as to contain 0.05% cobalt oxide in the composition. Using this mixed glass body obtained by mixing the crystalline glass body and the crystalline glass body obtained in Example 1 at a weight ratio of 4: 6, firing and cooling treatments were performed under the same conditions as in Example 1. To obtain a crystallized glass article. The obtained crystallized glass article was mixed with blue colored crystallized glass bodies and white crystallized glass bodies, and had a patchy pattern.

  The physical properties of the obtained crystallized glass article were measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
A glass raw material prepared to have the composition shown in Table 1 was melted at 1550 ° C. for 12 hours, and this molten glass was poured into water to obtain a crystalline glass body. When the linear thermal expansion coefficient of this crystalline glass was measured by the DILATO method, it was 72 × 10 ⁻⁷ / K and the transition temperature was 580 ° C. The viscosity was measured the temperature at a viscosity of 10 ⁴ and 10 ⁵ poise by parallel plate viscometer, 10 1110 ° C. in ⁴ poise, at 10 ⁵ poise was 1010 ° C..

  The obtained crystalline glass body was classified with a sieve to a particle size of 0.5 to 2.0 mm to obtain a grainy crystalline glass body. Next, 1 part by mass of Sn-Si-Ca-Cr-Zn-based sphene inorganic pigment powder is added to 100 parts by mass of the crystalline glass body, lightly mixed, and after a small amount of binder is added, it is mixed well. . 4. Next, a mold made of mullite cordierite coated with alumina powder and having an inner dimension of 450 mm × 650 mm × depth of 20 mm is prepared, and a crystalline glass body with the sphene pigment obtained above adhered to the surface. 6 kg was collected evenly. Then, it baked with the shuttle kiln in this state. As firing conditions, the temperature is raised at a rate of 100 ° C. for 1 hour, held at 1100 ° C. for 1 hour, then cooled at a rate of 100 ° C. for 1 hour, and then cooled in a furnace to obtain a fired body. A patterned crystallized glass article having a pink color was obtained.

In order to confirm the amount of crystals of the obtained crystallized glass article, after collecting a part of the crystalline glass particles in a refractory container, crystallized glass is obtained under the same firing and cooling conditions as described above. It was. As a result of X-ray diffraction measurement, the crystallized glass had a crystal precipitation amount of about 30%, and it was confirmed that the precipitated crystal was β-wollastonite (CaO · SiO ₂ ).

  The physical properties of the obtained crystallized glass article were measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
The glass raw material prepared so as to have the composition shown in Table 1 was melted at 1550 ° C. for 12 hours, and this molten glass was formed into a plate shape to a thickness of 5 mm with a roll to obtain a crystalline glass plate. The linear thermal expansion coefficient of this crystalline glass was measured by the DILATO method and found to be 69 × 10 ⁻⁷ / K. The viscosity was measured the temperature at a viscosity of 10 ⁴ and 10 ⁵ poise by parallel plate viscometer, 10 1115 ° C. in ⁴ poise, was 1060 ° C. at 10 ⁵ poise.

  The obtained crystalline glass plate was placed on a mullite cordierite shelf coated with alumina powder. In this state, it was baked with a roller hearth kiln. As firing conditions, the temperature is raised at a rate of 100 ° C. per hour, held at 1070 ° C. for 1 hour, then cooled at a rate of 100 ° C. per hour, and then cooled in a furnace to obtain a fired body, which is light. A crystallized glass plate article having a blue pattern and no pattern was obtained.

In order to confirm the amount of crystals of the obtained crystallized glass plate article, a part of the crystalline glass plate was placed on a fireproof shelf and crystallized glass was obtained under the same firing and cooling conditions as described above. . As a result of X-ray diffraction measurement, the crystallized glass had a crystal precipitation amount of about 13% by mass, and it was confirmed that the precipitated crystal was forsteinite (2MgO.SiO ₂ ) and garnite.

  The physical properties of the obtained crystallized glass article were measured in the same manner as in Example 1. The results are shown in Table 1.

  As is apparent from Table 1, in Examples 1 to 4, it was possible to obtain crystallized glass articles having good heat resistance and strength and having excellent design properties. On the other hand, the crystallized glass article of the comparative example was inferior in heat resistance and strength, and was not suitable as a top plate for a cooker.

(Examples 5 to 11)
(A) Production of Crystalline Glass Sample After uniformly mixing the raw materials prepared so as to have the glass composition shown in Table 2, it was melted at 1600 to 1650 ° C. for 12 hours using a platinum crucible. The molten glass was poured into water to produce a crystalline glass body.

  The obtained crystalline glass bodies were classified with a sieve to a particle size of 0.5 to 2.0 mm to obtain fine-grained grainy crystalline glass bodies. The crystalline glass bodies were uniformly accumulated in a refractory container laid with an alumina sheet and fired in this state in an electric furnace to obtain a crystallized glass sample. As firing conditions, the temperature was raised at a rate of 100 ° C./h, held at the prescribed firing temperature in Table 2 for 1 hour, and then cooled to room temperature at the prescribed cooling rate.

(B) Characteristics of crystallized glass sample Table 2 shows the characteristics of the obtained crystallized glass sample. Each characteristic was evaluated as follows.

  The average linear thermal expansion coefficient, glass transition temperature, and yield temperature at 30 to 380 ° C. of each crystallized glass sample were measured using a dilatometer (TD5010 manufactured by Bruker AXS).

  The analysis of the precipitated crystal in each crystallized glass sample was performed using an X-ray diffractometer (RINT2100 manufactured by Rigaku).

  The crystal precipitation state in each crystallized glass sample was observed using a scanning electron microscope (S-4300SE, manufactured by Hitachi High-Technologies Corporation). In order to clarify the contrast between the crystal particles and the matrix glass, the fracture surface of the crystallized glass sample was etched with hydrofluoric acid (2% by mass-25 ° C.) for 4 minutes. Further, the composition of the crystal phase and the matrix glass (excluding Li) was analyzed using an energy dispersive X-ray analyzer (EMAX Energy EX-250 manufactured by Horiba, Ltd.) attached to the present scanning electron microscope. The average particle size of the precipitated crystals is determined by measuring the particle size of the crystal in the electron microscope image of the observation region selected at random using an image processing system (WinRoof Ver. 5 manufactured by Mitani Corp.) and calculating the average value. Were determined. The volume crystallinity (vol%) was determined by converting the area ratio of the crystal phase obtained from the image analysis result into a volume ratio.

(C) Difference in average linear thermal expansion coefficient between matrix glass and crystal The difference between both was calculated from the average linear thermal expansion coefficient of each of the matrix glass and the crystal calculated by the following procedure.

(Average linear thermal expansion coefficient of crystal phase)
First, the SiO ₂ amount x (mol%) in the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal was determined by the following procedure. It has been reported that a proportional relationship is established between the amount of SiO ₂ in β-quartz solid solution and β-spodumene solid solution crystals and a specific interplanar spacing in the crystal lattice (The Chemical Society of Japan (1974), 505. -510, and Japan Analyst Vol. 22 (1973), pages 745-751). From this, the SiO ₂ amount x (mol%) in the β-quartz solid solution and β-spodumene solid solution crystals can be expressed by the following formulas, respectively.

β-quartz solid solution: x = (0.1004-d (406)) / 6.752E-5
β-spodumene solid solution: x = (0.1286-d (217)) / 1.009E-4

  Here, d (406) and d (217) are plane spacings (nm) between the (406) plane and the (217) plane in the crystal lattice of β-quartz solid solution (hexagonal crystal) and β-spodumene solid solution (tetragonal crystal), respectively. ).

Further, x is by using the following relationship can be converted to crystal composition molar ratio n when expressed as _{Li 2 O · Al 2 O 3} · nSiO 2.

    n = 2x / (100-x)

Using the interplanar spacing of the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal determined by the X-ray diffraction method, the molar ratio n of SiO ₂ amount x (mol%) and SiO ₂ in each crystal phase from the above formula. It was determined.

Subsequently, the average linear thermal expansion coefficient of the Li ₂ O—Al ₂ O ₃ —SiO ₂ based crystal was determined by the following procedure. It has been reported that the linear thermal expansion coefficient of Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal is correlated with the molar ratio n of SiO _{2 in} the crystal (Glastechn. Ber. 40 (1967)). 385, and J. Amer. Ceram. Soc. 51 (1968), 651). From this, the relationship between the average linear thermal expansion coefficient of the β-quartz solid solution and the β-spodumene solid solution crystal and the molar ratio n of SiO ₂ is expressed by the following equations, respectively.

β-quartz solid solution:
When n <3 (Average linear thermal expansion coefficient) = (84.131n-218.18) × 10 ⁻⁷
In the case of 3 ≦ n ≦ 10 (Average linear thermal expansion coefficient) = − 11.5 × 10 ⁻⁷
When 10 <n <14 (Average linear thermal expansion coefficient) = (40.115 n−403.28) × 10 ⁻⁷

β-spodumene solid solution:
When 4 ≦ n ≦ 7 (Average linear thermal expansion coefficient) = (− 0.0581 n ³ +1.3829 n ² −12.284n + 37.632) × 10 ⁻⁷

The average linear thermal expansion coefficient of the crystal phase was determined from the above formula using the molar ratio n of SiO ₂ in the Li ₂ O—Al ₂ O ₃ —SiO ₂ -based crystal determined by the X-ray diffraction method.

(Average linear thermal expansion coefficient of matrix glass)
First, in order to determine the composition of the matrix glass, the mass crystallinity was calculated from the volume crystallinity of the crystallized glass and the density of the crystal phase and the matrix glass. Here, as the density of the crystal phase, the density of crystals having a similar molar ratio n reported in the powder X-ray diffraction data file (ICDD) was used. As the density of the matrix glass, the density of the crystalline glass that is a precursor of the crystallized glass was used.

Subsequently, each component content (mol%) of the remaining matrix glass was determined by subtracting each component content (mol%) of the crystal phase from each component content (mol%) of the crystalline glass. Here, from the results of energy dispersive X-ray analysis, TiO ₂ and ZrO ₂ in the composition are distributed in equimolar amounts to the crystal phase and the matrix glass, and other components other than Li ₂ O, Al ₂ O ₃ , and SiO _2. Were all distributed in matrix glass. In the partition calculation, the contents of Li ₂ O and Al ₂ O ₃ were determined so that the mass% of the crystal phase coincided with the mass crystallinity described above.

  Subsequently, the average linear thermal expansion coefficient of the matrix glass was determined by the following procedure. It is known that an additivity rule is established between the coefficient of linear thermal expansion of glass and the composition, and additivity factors of each glass component have been reported (GLASS SCIENCE AND TECHNOLOGY 9, Mathematical Approach to Glass, chapter 15-16).

Using the composition of the matrix glass determined by the above procedure, the average linear thermal expansion coefficient of the matrix glass was determined according to the procedure described in the literature (Appen or Gan Fu-Si method). It was confirmed that the linear thermal expansion coefficient of the crystalline glass calculated by this method coincided with the actual measurement value with an accuracy within ± 1.5 × 10 ⁻⁷ / K.

  The difference between the two was determined from the crystal phase obtained by the above procedure and the average linear thermal expansion coefficient of the matrix glass.

(D) Theoretical value of average linear thermal expansion coefficient of crystallized glass The theoretical value of average linear thermal expansion coefficient of crystallized glass is based on an addition rule using the average linear thermal expansion coefficient and volume crystallinity of crystal and matrix glass. It was calculated by the following formula.

  (Theoretical value of average linear thermal expansion coefficient) = ((Volume crystallinity) × (Average linear thermal expansion coefficient of crystal) + (100− (Volume crystallinity)) × (Average linear thermal expansion coefficient of matrix glass)) / 100

In the crystallized glass samples of Examples 5 to 11, β-spodumene solid solution or β-quartz solid solution was precipitated as the main crystal. The average particle diameter of the main crystal was 5 to 20 μm for the β-spodumene solid solution and 80 μm for the β-quartz solid solution. Furthermore, the difference between the average linear thermal expansion coefficients of the matrix glass and the crystals at 30 to 380 ° C. is 46.3 × 10 ^{−7 to} 67.8 × 10 ⁻⁷ / K, both of which are 35 × 10 ⁻⁷ / K or more. Therefore, a low linear thermal expansion coefficient of 1.4 × 10 ^{−7 to} 25.6 × 10 ⁻⁷ / K was exhibited. These linear thermal expansion coefficients were lower than the linear thermal expansion coefficient calculated additively using the average linear thermal expansion coefficient and volume fraction of crystal and matrix glass. The yield temperature was 900 ° C. or less in any sample, and bending by heating was possible.

(Comparative Examples 3 and 4)
A glass raw material prepared to have the composition shown in Table 2 was melted at 1550 ° C. for 12 hours, and then the molten glass was poured into water to produce a crystalline glass body.

The obtained crystalline glass body was classified with a sieve to a particle size of 0.5 to 2.0 mm to obtain a grainy crystalline glass body. The crystalline glass bodies were uniformly accumulated in a refractory container laid with an alumina sheet and fired in this state in an electric furnace to obtain a crystallized glass sample. As firing conditions, the temperature was raised at a rate of 120 ° C./h, held at the prescribed firing temperature in Table 1 for 1 hour, and then cooled to room temperature at a rate of 120 ° C./h. About the obtained crystallized glass article, the characteristic evaluation was performed similarly to Examples 5-10. In addition, the literature value was applied as an average linear thermal expansion coefficient of the precipitated β-wollastonite crystal (CaSiO ₃ ). The results are shown in Table 3.

In Comparative Examples 3 and 4, about 30% by mass of β-wollastonite crystal was precipitated as the main crystal. In Comparative Examples 3 and 4, the average linear thermal expansion coefficient at 30 to 380 ° C. of the main crystal is large at 65 × 10 ⁻⁷ / K, and the difference between the average linear thermal expansion coefficients at 30 to 380 ° C. between the matrix glass and the crystal is Since it was smaller than 35 × 10 ⁻⁷ / K, a low expansion crystallized glass article could not be obtained. Moreover, since the linear thermal expansion coefficient of the crystallized glass article in Comparative Examples 3 and 4 was 60 × 10 ⁻⁷ / K, which was larger than 30 × 10 ⁻⁷ / K, the thermal durability was low.

  The crystallized glass article of the present invention is suitable as a cooking appliance top plate, particularly a gas stove top plate, a kitchen appliance top plate, a table top and other kitchen equipment decoration materials, and other various interior and exterior materials.

Claims (10)

Integrating a crystalline glass masses, the Rukoto are fused integrally and crystallized by heat treatment, a crystallized glass article each crystallized glass masses is then fused together at the interface, Li ₂ O -Al ₂ O ₃ -SiO ₂ system crystals contain 20-60 weight%, crystallized glass article linear thermal expansion coefficient at 30 to 380 ° C. is characterized 0~30 × ^{10 -7} / K der Rukoto . The crystallized glass article according to claim 1, wherein the particle size of the crystalline glass body is 0.1 to 20 mm.   The crystallized glass article according to claim 1, wherein the glass transition temperature is 600 ° C. or higher. The crystallized glass article according to any one of claims 1 to 3, comprising a garnite (ZnO.Al ₂ O ₃ ) crystal as a part of the crystal. Crystalline glass masses are, in _{mass%, SiO 2 55~72%, Ai} 2 O 3 14~30%, Li 2 O 1.5~5%, K 2 O 1~10%, TiO 2 0~5 %, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 0-7%, ZnO 0-10%, MgO 0-2.5%, CaO 0-2.5%, BaO 0-8%, B ₂ O ₃ The crystallized glass article according to claim 1, comprising a composition of 0 to 7%, Na ₂ O 0 to 2%, P ₂ O ₅ 0 to 0.8%. Crystalline glass masses are, in _{mass%, SiO 2 55~72%, Ai} 2 O 3 14~30%, Li 2 O 1.5~5%, K 2 O 1~10%, TiO 2 1~5 %, ZrO ₂ 0-4%, TiO ₂ + ZrO ₂ 2.5-7%, ZnO 0-10%, MgO 0-2.5%, CaO 0-2.5%, BaO 0-3%, B ₂ The crystallized glass article according to claim 1, comprising a composition of O ₃ 0-7%, Na ₂ O 0-2%, P ₂ O ₅ 0-0.8%. .   Using a crystalline glass body made by adhering 3 parts by mass or less of a metal oxide powder or an inorganic pigment powder to 100 parts by mass of a crystalline glass body, and at the interface of each fused crystallized glass body The crystallized glass article according to any one of claims 1 to 6, wherein a colored layer comprising a metal oxide powder or an inorganic pigment powder is exposed.   8. At least a part of the crystalline glass body is provided with a colored crystallized glass portion by containing 5% by mass or less of a coloring component in the composition. Crystallized glass article. The crystallized glass article according to any one of claims 1 to 8 , wherein the crystallized glass article is used for a cooking appliance top plate or a kitchen equipment decoration material. A method for producing a crystallized glass article according to any one of claims 1 to 9 , wherein the crystallized glass bodies are accumulated in a refractory mold, and the temperature is equal to or higher than the softening point of the crystalline glass bodies. A method characterized in that heat treatment is performed in order to fuse and integrate and crystallize.