JPWO2019117122A1 - Manufacturing method of LAS-based crystallized glass plate and LAS-based crystallized glass plate - Google Patents

Abstract

The method for producing a LAS-based crystallized glass plate of the present invention is a step for preparing a crystalline glass plate and a step of preparing a crystalline glass plate in the method for producing a LAS-based crystallized glass plate containing a β-spodium solid solution as a main crystal phase, and 300 to 900 ° C./ The temperature of the crystalline glass plate is raised to the maximum heat treatment temperature of more than 900 ° C. at the heating rate of time, and the β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated to form a LAS-based crystallized glass plate. It is characterized by having a step of obtaining.

Description

The present invention relates to a method for producing a Li ₂ O-Al ₂ O _3- SiO ₂ system (hereinafter referred to as LAS system) crystallized glass plate and a LAS system crystallized glass plate.

Not only gas cookers that use a gas stove, but also infrared cookers and electromagnetic cookers that use radiant heaters and halogen heaters are used as cookers for home and business use. Since high thermal efficiency, safety, and thermal shock resistance are required for the top plate used in the electromagnetic heating cooker, a crystallized glass plate having a small amount of electromagnetic induction heating and a low coefficient of thermal expansion is used.

By the way, the role of the top plate is to prevent water, seasonings, food, etc. from scattering to the heating device, and to conceal the internal structure of the cooking device such as the heating device, wiring, etc. To increase.

When a crystallized glass plate is used as the top plate, there are mainly two methods for concealing the internal structure of the cooker. The first method is a method of making the low-expansion crystallized glass plate itself opaque or translucent. For example, Patent Document 1 discloses low-expansion crystallized glass colored darkly by a colorant, and Patent Document 2 discloses low-expansion glass having visible light transmission characteristics in the range from transparent to opaque. A crystallized glass plate is disclosed. The second method is a method in which a decorative film is formed on the surface of a transparent low-expansion crystallized glass plate by a printing method, and the internal structure of the cooker is concealed by the decorative film. For example, Patent Document 3 describes a crystallized glass plate provided with a raster-colored decorative film made of a precious metal and a base metal on the back surface (the surface opposite to the cooking surface).

However, since the crystallized glass plate described in Patent Document 1 has a dark color tone, there is a problem that it is difficult to transmit the light of an indicator that displays the amount of applied power or the like. That is, when the crystallized glass plate described in Patent Document 1 is used for the top plate of the electromagnetic heating cooker, if the indicator is provided on the back surface side of the top plate, the light of the red indicator is barely visible from the cooking surface side. Even if the indicator emits a color other than red, the light of such a color cannot be displayed on the cooking surface side because the top plate does not transmit light other than red (for example, blue or yellow) at all. When the indicator emits a color other than red, it is necessary to make a hole at a predetermined position on the top plate in order to display the light of that color on the cooking surface side, and as a result, the top plate is chipped or cracked. Is likely to occur. Furthermore, as one of the factors that enhance the commercial value of the top plate for cookers, the appearance design is being emphasized. In the past, dark colors were the mainstream, but recently, bright colors are being preferred. However, since the crystallized glass plate of Patent Document 1 has a dark color tone, it cannot sufficiently meet the recent tastes of consumers.

Further, the crystallized glass plate described in Patent Document 2 contains 2 to 5% by mass of ZnO in order to precipitate zinc oxide stones in the glass. However, when a large amount of ZnO is contained in this way, Dissimilar crystals are likely to precipitate during heat treatment. As a result, when trying to obtain a translucent color tone, there arises a problem that the color tone tends to change subtly, which makes stable production difficult.

Further, in the crystallized glass plate described in Patent Document 3, since the color tone and gloss of the decorative film are directly reflected in the appearance of the top plate, the top plate becomes too conspicuous, does not harmonize with the entire kitchen, and spoils the aesthetic appearance. May occur. Further, if the gloss of the decorative film is too strong, light such as lighting is reflected, and there is a problem that the cook is dazzling and difficult to cook.

Special Fair 3-9056 Gazette Japanese Unexamined Patent Publication No. 5-213629 Special Fair 7-17409 Gazette Special Table 2001-501168 Gazette Japanese Patent No. 4315075

Under these circumstances, Patent Document 4 discloses a top plate having a new appearance and optical characteristics. The top plate is made of a LAS-based crystallized glass plate and exhibits a cloudiness of 50% or more. It contains a β-spodium solid solution with a small crystal grain size. However, a crystallized glass plate having a small crystal grain size does not easily scatter visible light and has high transparency, so that the color tone is very light and it is difficult to hide the internal structure of the cooker.

Further, Patent Document 5 discloses a translucent LAS-based crystallized glass plate in which a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated. Since this crystallized glass plate has a bright color and is not too conspicuous, it is possible to display the light of various indicators. However, since this crystallized glass plate has undergone a long crystallization step (a heat treatment step of at least 8 hours), there is a problem that the manufacturing cost rises.

The present invention has been made in view of such circumstances, and the technical problem thereof is that the internal structure of the cooker can be concealed with a bright color, and even when the decorative film is formed on the back side, the decorative film can be formed. It is to devise a method for efficiently producing a LAS-based crystallized glass plate that is not too conspicuous and a LAS-based crystallized glass plate.

As a result of diligent studies by the present inventor, it has been found that the above technical problems can be solved by strictly regulating the heat treatment conditions of the crystalline glass plate, and the present invention is proposed. That is, the method for producing a LAS-based crystallized glass plate of the present invention is a step for preparing a crystalline glass plate and 300 to 900 in the method for producing a LAS-based crystallized glass plate containing a β-spojumen solid solution as a main crystal phase. The crystalline glass plate is heated to a maximum heat treatment temperature of more than 900 ° C. at a temperature rising rate of ° C./hour, and a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated to form LAS-based crystallization. It is characterized by having a step of obtaining a glass plate.

In the method for producing a LAS-based crystallized glass plate of the present invention, the crystalline glass plate is heated to a maximum heat treatment temperature of over 900 ° C. at a heating rate of 300 to 900 ° C./hour, and the average crystal grain size is 100. It has a step of precipitating a β-spodium solid solution having a diameter of about 1000 nm to obtain a LAS-based crystallized glass plate. By doing so, it is possible to efficiently produce a LAS-based crystallized glass plate having a bright color and in which the decorative film is not too conspicuous when the decorative film is formed on the back side. That is, a crystallized glass plate having an opal-like and translucent appearance can be produced in a short time.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, the holding time at (maximum heat treatment temperature ± 10 ° C.) is preferably less than 60 minutes. In this way, the productivity of the crystallized glass plate can be increased.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, it is preferable to precipitate a β-spodium solid solution having an average crystal grain size of 150 to 900 nm.

Further, the method for producing a LAS-based crystallized glass plate of the present invention is a LAS-based method in which the brightness value L ^{* of} the L ^* a ^* b ^* display system conforming to JIS Z8729 is 30 to 80 in terms of plate thickness of 3.0 mm. It is preferable to obtain a crystallized glass plate. In this way, it becomes easy to obtain an opal-like appearance having an excellent appearance.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, it is preferable to obtain a LAS-based crystallized glass plate having an average transmittance of 10 to 50% at a wavelength of 400 to 800 nm in terms of a plate thickness of 3.0 mm. .. By doing so, it becomes easy to optimize the amount of light transmitted through the top plate.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, it is preferable to obtain a LAS-based crystallized glass plate having an average transmittance of 50% or more at a wavelength of 800 to 1500 nm in terms of a plate thickness of 3.0 mm. This makes it easier for heat rays to pass through during cooking.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, a LAS-based crystallized glass plate having an average coefficient of linear thermal expansion at 30 to 750 ° C. of −10 × ^10-7 to +30 × ^10-7 / ° C. is used. It is preferable to obtain. In this way, the crystallized glass plate is less likely to be damaged even when a large temperature distribution is generated inside the top plate. As a result, it becomes easy to apply to the top plate for cookers.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, it is preferable that the ZnO content in the LAS-based crystallized glass plate is less than 2% by mass. In this way, dissimilar crystals are less likely to precipitate during the heat treatment.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, the LAS-based crystallized glass plate has a composition of SiO ₂ 55 to 75%, Al ₂ O ₃ 15 to 30%, Li ₂ O in mass%. 2~6%, 0~3% MgO, BaO 0~5%, ZnO less than _{0~2%, TiO 2 1~6%,} ZrO 2 0~4%, P 2 O 5 0~5%, Na 2 O It preferably contains 0 to 4% and K ₂ O 0 to 4%.

Further, in the method for producing a LAS-based crystallized glass plate of the present invention, it is preferable to use the LAS-based crystallized glass plate as a top plate for a cooker.

The LAS-based crystallized glass plate of the present invention is a LAS-based crystallized glass plate in which a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated, and conforms to JIS Z8729 in terms of plate thickness of 3.0 mm. It is characterized in that the brightness value L ^{* of} the L ^* a ^* b ^* display system is 30 to 80.

Further, the LAS-based crystallized glass plate of the present invention preferably has an average transmittance of 10 to 50% at a wavelength of 400 to 800 nm in terms of a plate thickness of 3.0 mm.

Further, the LAS-based crystallized glass plate of the present invention preferably has an average transmittance of 50% or more at a wavelength of 800 to 1500 nm in terms of a plate thickness of 3.0 mm.

Further, the LAS-based crystallized glass plate of the present invention preferably has an average linear thermal expansion coefficient of −10 × 10 ⁻⁷ to + 30 × 10 ⁻⁷ / ° C. at 30 to 750 ° C.

The LAS-based crystallized glass plate of the present invention has a composition of SiO ₂ 55 to 75%, Al ₂ O ₃ 15 to 30%, Li ₂ O 2 to 6%, MgO 0 to 3%, by mass%. BaO 0 to 5%, ZnO less than _{0~2%, TiO 2 1~6%,} ZrO 2 0~4%, P 2 O 5 0~5%, Na 2 O 0~4%, K 2 O 0~4 It is preferable to contain%.

Further, the LAS-based crystallized glass plate of the present invention has a composition of SiO ₂ 60 to 70%, Al ₂ O _{3 over} 20 to 30%, Li ₂ O 3 to 5%, MgO 0 to 1% in mass%. , BaO 1~2%, ZnO less than _{0~0.4%, TiO 2 1~4%,} ZrO 2 2~3%, P 2 O 5 0~2%, Na 2 O 0~4%, K 2 O It preferably contains 0 to 4%.

The method for producing a LAS-based crystallized glass plate of the present invention includes a step of preparing a crystalline glass plate. The crystalline glass plate can be produced by a known method. For example, a crystalline glass plate can be produced by blending glass raw materials so as to have a predetermined composition, melting the obtained glass batch at a temperature of 1550 to 1750 ° C., and then molding the glass into a plate shape. .. The molding method includes a float method, a rollout method, a press method, etc. However, if the surface smoothness of the crystalline glass plate is to be improved, the float method is preferable, and if a large crystalline glass plate is to be produced, the float method is preferable. , The roll-out method is preferable, and the press method is preferable when it is desired to suppress devitrification during molding.

The method for producing a LAS-based crystallized glass plate of the present invention is characterized in that the temperature of the crystalline glass plate is raised to a maximum heat treatment temperature of over 900 ° C. (preferably 1000 to 1230 ° C.). If the maximum heat treatment temperature is too low, the β-quartz solid solution tends to precipitate, so that the transparency becomes high and it becomes difficult to obtain an opal-like translucent appearance.

The method for producing a LAS-based crystallized glass plate of the present invention is characterized in that the temperature of the crystalline glass plate is raised at a heating rate of 300 to 900 ° C./hour (preferably a heating rate of 350 to 850 ° C./hour). And. When the rate of temperature rise is low, the crystal grain size becomes coarse, so that the white turbidity becomes too strong and the crystal grain size tends to become opaque. On the other hand, when the rate of temperature rise is high, the grain size becomes finer, so that the scattering effect of visible light is reduced, the transparency is increased, and it becomes difficult to obtain an opal-like translucent appearance.

In the method for producing a LAS-based crystallized glass plate of the present invention, the holding time at (maximum heat treatment temperature ± 10 ° C.) is preferably less than 60 minutes, particularly less than 45 minutes. If the holding time near the maximum heat treatment temperature is too long, the manufacturing cost of the crystallized glass plate increases. Further, since the crystal grain size becomes coarse, the white turbidity becomes too strong and tends to become opaque.

In the method for producing a LAS-based crystallized glass plate of the present invention, a nucleation step for forming crystal nuclei may be provided before the temperature is raised to the maximum heat treatment temperature. In this way, in the heat treatment step (crystal growth step) in which the temperature is raised to the maximum heat treatment temperature, a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm can be easily precipitated. As a result, it is possible to stably produce a LAS-based crystallized glass plate having a bright color and in which the decorative film is not too conspicuous when the decorative film is formed on the back side. The heat treatment temperature in the nucleation step is preferably 700 to 950 ° C., 750 to 950 ° C., particularly 750 to 930 ° C. If the heat treatment temperature is out of the above range, it becomes difficult to properly perform nucleation. The heat treatment time in the nucleation step is preferably 7 hours or less, 5 hours or less, and particularly preferably 4 hours or less. If the heat treatment time is too long, the production cost of the LAS-based crystallized glass plate tends to increase. In the nucleation step, it may be held only once at a predetermined temperature, but it is preferable to hold it a plurality of times from the viewpoint of appropriately obtaining a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm. Further, the nucleation step may be performed while raising the temperature without maintaining the temperature at a specific temperature.

The method for producing a LAS-based crystallized glass plate of the present invention is characterized in that a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated to obtain a LAS-based crystallized glass plate. When a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated, an elegant appearance with a bright and soft color can be obtained. Further, it becomes possible to appropriately scatter visible light, and an excellent antiglare effect can be enjoyed.

The average particle size of the β-spodium solid solution is 100 to 1000 nm, preferably 150 to 900 nm, and more preferably 200 to 900 nm. If the average particle size of the β-spojumen solid solution is too small, the effect of scattering visible light is reduced, the transparency is increased, and it becomes difficult to obtain an opal-like translucent appearance. On the other hand, if the average particle size of the β-spojumen solid solution is too large, the white turbidity becomes too strong and it tends to become opaque. Here, the "opal tone" means an appearance or a color tone having a peculiar scattering of visible light, which is generally characteristic of opal. Such appearance and color tone are obtained by scattering the particles, which are scattering bodies, in a short wavelength region of visible light, so that the transmitted light of the object is yellowish and the scattered light is bluish.

In the LAS-based crystallized glass plate according to the present invention, the brightness value L ^* of the L ^* a ^* b ^* display system conforming to JIS Z8729 is preferably 30 to 80, more preferably 30 in terms of plate thickness of 3.0 mm. It is ~ 70, more preferably 30-60. When the brightness value L ^* is out of the above range, it becomes difficult to obtain an opal-like appearance with excellent aesthetics.

In the LAS-based crystallized glass plate according to the present invention, the average transmittance at a wavelength of 400 to 800 nm is preferably 10 to 50%, more preferably 15 to 40%, still more preferably 18 to 18 to a thickness of 3.0 mm. It is 30%, and 20% or more is preferable when it is desired to transmit the light of a blue or yellow indicator. If the average transmittance at a wavelength of 400 to 800 nm is too low, the amount of light transmitted through the top plate is too small, and it becomes difficult to obtain an opal-like appearance. In addition, it becomes difficult to visually recognize the light of the indicator provided on the back surface side of the top plate. On the other hand, if the average transmittance at a wavelength of 400 to 800 nm is too high, the light scattering property is lowered and the color tone becomes very light, so that it becomes difficult to hide the internal structure of the cooker. If the average transmittance at a wavelength of 400 to 800 nm is regulated within the above range in terms of plate thickness of 3.0 mm, even if a highly glossy decorative film is formed on the back surface of the top plate, the reflected light from this decorative film will be generated. Since it is scattered moderately inside the top plate, the sharp glossy color is alleviated, and it becomes easy to obtain a high-class appearance having a soft hue.

In the LAS-based crystallized glass plate according to the present invention, the average transmittance at a wavelength of 800 to 1500 nm is preferably 50% or more, more preferably 60% or more, and particularly preferably 70 to 90% in terms of plate thickness of 3.0 mm. Is. If the average transmittance at a wavelength of 800 to 1500 nm is too low, it becomes difficult to transmit heat rays, and thus it becomes difficult to heat the object to be cooked.

Since the crystallized glass plate used for the top plate for a cooker is repeatedly heated and cooled, it is required to have a low coefficient of thermal expansion and excellent thermal shock resistance. In the LAS-based crystallized glass plate according to the present invention, the average coefficient of linear thermal expansion at 30 to 750 ° C. is preferably −10 × 10 ⁻⁷ to + 30 × 10 ⁻⁷ / ° C., more preferably −10 × 10 ^−7. ~ + 20 × 10 ^-7 / ° C. If the average coefficient of linear thermal expansion at 30 to 750 ° C. is out of the above range, it may be divided by the expansion difference when a large temperature distribution occurs inside the top plate.

In the LAS-based crystallized glass plate according to the present invention, the crystallinity of the LAS-based crystallized glass plate is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more. If the crystallinity is too low, the coefficient of thermal expansion increases and the thermal shock resistance tends to decrease.

The LAS-based crystallized glass plate according to the present invention has a composition of SiO ₂ 55 to 75%, Al ₂ O ₃ 15 to 30%, Li ₂ O 2 to 6%, MgO 0 to 3%, BaO in mass%. 0 to 5%, less than _{0~2% ZnO, TiO 2 1~6%} , ZrO 2 0~4%, P 2 O 5 0~5%, Na 2 O 0~4%, K 2 O 0~4% Is preferably contained. The reason for limiting the composition of the LAS-based crystallized glass plate is as follows. In the description of the content range of each component, the% indication means mass%.

SiO ₂ is a glass network former and is a component constituting LAS-based crystals. However, when the content of SiO ₂ is low, the glass tends to be devitrified during molding or slow cooling, and the chemical durability is also likely to decrease. On the other hand, as the content of SiO ₂ increases, the solubility of the glass batch tends to decrease. Therefore, the content of SiO ₂ is preferably 55 to 75%, more preferably 60 to 70%.

Al ₂ O ₃ is a component constituting LAS-based crystals. However, when the content of Al ₂ O ₃ decreases, the meltability tends to decrease. On the other hand, when the content of Al ₂ O ₃ is large, the glass tends to be devitrified during molding or slow cooling, and the chemical durability is also likely to decrease. Therefore, the content of Al ₂ O ₃ is preferably 15 to 30%, more preferably 15 to 25%, and even more preferably more than 20 to 25%.

Li ₂ O is a component constituting LAS-based crystals. However, when the Li ₂ O content is low, LAS-based crystals are less likely to precipitate. On the other hand, as the content of Li ₂ O increases, the chemical durability tends to decrease. Therefore, the content of Li ₂ O is preferably 2 to 6%, more preferably 3 to 5%.

MgO is a component that facilitates precipitation of LAS-based crystals. However, when the content of MgO increases, the coefficient of thermal expansion becomes too high. Therefore, the content of MgO is preferably 0 to 3%, more preferably 0 to 2%, still more preferably 0 to 1.5%, and particularly preferably 0 to 1%.

BaO is a component that enhances meltability and prevents the occurrence of devitrified lumps. However, when the BaO content increases, it becomes difficult for LAS-based crystals to precipitate. In addition, the coefficient of thermal expansion becomes high, and the thermal characteristics tend to deteriorate. Therefore, the content of BaO is preferably 0 to 5%, more preferably 0 to 4%, still more preferably 0 to 3%, and particularly preferably 1 to 2%.

ZnO is a component that enhances meltability and facilitates precipitation of LAS-based crystals. However, when the ZnO content is high, the glass tends to be devitrified during molding, and dissimilar crystals are likely to precipitate during slow cooling or crystallization. Therefore, the ZnO content is preferably less than 2%, more preferably less than 1.5%, still more preferably less than 1%, and particularly preferably less than 0.4%.

TiO ₂ is a component that acts as a nucleating agent. When the content of TiO ₂ is low, the LAS-based crystals become coarse and the chemical durability tends to be lowered. On the other hand, when the content of TiO ₂ is large, the color tone becomes brown and it becomes difficult to secure an opal-like appearance. Therefore, the content of TiO ₂ is preferably 1 to 6%, more preferably 1 to 5%, and even more preferably 1 to 4%.

ZrO ₂ is a component that acts as a nucleating agent. When the content of ZrO ₂ is large, the glass tends to be devitrified during molding or slow cooling. Therefore, the content of ZrO ₂ is preferably 0 to 4%, more preferably 0 to 3%, still more preferably 1 to 3%, and particularly preferably 2 to 3%.

The total amount of TiO ₂ and ZrO ₂ is preferably 2 to 6.9%, more preferably 3 to 6.5%, and even more preferably 3.5 to 5.5%. When the total amount of TiO ₂ and ZrO ₂ is small, the LAS-based crystals become coarse and the chemical durability tends to decrease. On the other hand, when the total amount of TiO ₂ and ZrO ₂ is large, the solubility of the glass batch tends to decrease, and the color tone becomes brown, making it difficult to secure an opal-like appearance.

P ₂ O ₅ is a component that significantly improves the poor solubility of ZrO ₂ . As the content of P ₂ O ₅ increases, the glass becomes easier to separate. Therefore, the content of P ₂ O ₅ is preferably 0 to 5%, more preferably 0 to 3%, and even more preferably 0 to 2%.

Na ₂ O and K ₂ O are components that enhance the solubility of glass batches. However, if the contents of Na ₂ O and K ₂ O are high, the chemical durability may be significantly reduced. In addition, the crystallinity is lowered and the coefficient of thermal expansion becomes too high. Therefore, the contents of Na ₂ O and K ₂ O are preferably 0 to 4%, particularly preferably 0 to 3%, respectively.

In addition to the above components, components such as CaO and PbO may be added up to 2% each. Addition of these components can enhance solubility, clarity, homogeneity and the like. In order to further enhance the clarity, one or more of SnO ₂ , Cl, SO ₃ , and Fe ₂ O ₃ may be added up to 0.5% in total.

When the LAS-based crystallized glass plate is highly transparent, if a highly glossy decorative film is formed on the back surface (the inner surface of the cooker), light such as lighting is reflected and the glass plate tends to be dazzled. On the other hand, since the LAS-based crystallized glass plate according to the present invention has an opal-like and translucent appearance, even if a decorative film having a strong gloss (for example, a TiN film) is formed, the reflected light is appropriately scattered inside the film. Therefore, it is possible to obtain a high-class appearance having a soft hue. That is, since the LAS-based crystallized glass plate according to the present invention has an antiglare effect that appropriately suppresses specularly reflected light, it is possible to apply a decorative film having a strong gloss. As a result, the design variation is greatly expanded, and the appearance design can be improved more than before.

The decorative film is composed of a nitride of one metal selected from the group consisting of Ti, Nb, W and Mo, and a group consisting of Si, Ti, Al, Nb, W, Mo, Sn, Cr, Pt and Au. Includes a nitride of one alloy selected from the group consisting of one selected metal, stainless steel, Hastelloy, Inconel and Nichrome, and one alloy selected from the group consisting of stainless steel, Hastelloy, Inconel and Nichrome. A membrane is suitable. In particular, a light-shielding film made of TiN is preferable because when the nitrogen content in the film is changed, the appearance changes steplessly in ascending order of nitrogen content, such as silver, gold, reddish black, and black. ..

Further, in order to prevent oxidation and alteration of the light-shielding film, it is possible to form an antioxidant film in addition to the light-shielding film. The antioxidant film is selected from the nitride of one or more metals selected from the group consisting of Si, Ti, Al, Nb, W, Mo, Ta and Sn, or the group consisting of Si, Al and Ti. A film containing an oxide of one of the above metals is suitable, and can be formed on the upper layer of the light-shielding film or can be formed between the LAS-based crystallized glass plate and the light-shielding film.

The LAS-based crystallized glass plate of the present invention is a LAS-based crystallized glass plate in which a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated, and conforms to JIS Z8729 in terms of plate thickness of 3.0 mm. It is characterized in that the brightness value L ^{* of} the L ^* a ^* b ^* display system is 30 to 80. Since the technical features of the LAS-based crystallized glass plate of the present invention have already been described in the explanation column of the method for producing the LAS-based crystallized glass plate of the present invention, detailed description thereof will be omitted here.

Hereinafter, the present invention will be described based on examples. The following examples are merely examples. The present invention is not limited to the following examples.

Table 1 shows Examples (Samples Nos. 1 to 3) and Comparative Examples (Samples Nos. 4 and 5) of the present invention.

First, the composition is SiO ₂ 65.6%, Al ₂ O ₃ 22.2%, Li ₂ O 3.7%, MgO 0.7%, BaO 1.2%, TiO ₂ 2.0 in mass%. %, ZrO ₂ 2.2%, P ₂ O ₅ 1.4%, Na ₂ O 0.4%, K ₂ O 0.3%, SnO ₂ 0.3%. It was mixed and a glass batch was prepared. Next, using a platinum crucible, the glass batch was melted at 1600 ° C. for 23 hours, further heated to 1650 ° C. and melted for 1 hour. Then, it was poured onto a carbon table, molded to a thickness of 5 mm with a molding roller, and then cooled in a slow cooling furnace at 700 ° C.

Subsequently, the obtained crystalline glass plate was heated from room temperature to the maximum heat treatment temperature in the table at the heating rate in the table, and then held for the holding time in the table to obtain the crystallized glass plate. Made. In addition, the main crystal phase of each sample, average crystal grain size, crystallinity, average linear thermal expansion coefficient, L ^* a ^* b ^* brightness value of the display system L ^* , average transmittance, diffuse reflectance, appearance and antiglare. Was evaluated. The results are shown in the table.

The main crystal phase and crystallinity were evaluated by X-ray diffraction by the powder method using RINT-2100 manufactured by Rigaku. In the table, "β-S" means a β-spodium solid solution, and "β-Q" means a β-quartz solid solution. The average crystal grain size was obtained by observing a part of the crystallized glass plate with an electron microscope. Specifically, the average crystal grain size is in the range of 1 mm from the outermost surface and 1 mm to 1.5 mm in depth. It is a value obtained by extracting two observation points of 1 cm ² each in a range of 1.5 mm to a depth of 2 mm and averaging their crystal grain sizes. The average transmittance and the diffuse reflectance are values measured using a spectrophotometer UV-3100 manufactured by Shimadzu Corporation. The brightness value L ^* of the L ^* a ^* b ^* display system is a value measured by a method conforming to JIS Z8729. A mirror-polished product with a wall thickness of 3.0 mm was used as a measurement sample for the average transmittance, the diffuse reflectance, and the brightness value L ^* of the L ^* a ^* b ^* display system. As for the diffuse reflectance, the incident angle was set to 8 ° and the total reflectance was measured. The average coefficient of linear thermal expansion is a value measured by a differential detection type relative expansion meter in a temperature range of 30 to 750 ° C. The appearance was evaluated by visual observation. Specifically, when each sample was placed on a black background, a case where pale scattered light was observed and transmitted light was observed in yellow was evaluated as an opal tone. The anti-glare property is that when a TiN film having a film thickness of 0.5 μm is formed on one side of each sample by a sputtering method and the side surface on which the TiN film is not formed is illuminated with a 40 W lamp, it is dazzled by direct viewing of reflected light. The case where no feeling of glare was felt was evaluated as "good", and the case where the feeling of glare was felt was evaluated as "bad".

As is clear from Table 1, the sample No. Nos. 1 to 3 have a heating rate of 400 to 800 ° C./hour, a maximum heat treatment temperature of 1130 ° C., a holding time of 5 to 30 minutes, a main crystal phase of β-spodium solid solution, and an average crystal grain size of 400 to 900 nm. The brightness value L ^* is 30.8 to 51.5, the average transmittance at a wavelength of 400 to 800 nm is 12.5 to 26.3%, and the average transmittance at a wavelength of 800 to 1500 nm is 57.9 to 74.8%. The coefficient of thermal expansion was ⁺¹¹ × ^10-7 / ° C, the appearance was opal-like, and the antiglare property was good. Therefore, the sample No. It is considered that Nos. 1 to 3 have a bright luster, are not too conspicuous, and have a low production cost.

On the other hand, sample No. In No. 4, since the temperature rising rate was low, the average crystal grain size was 1200 nm, and the appearance became white and opaque. In addition, sample No. In No. 5, since the temperature rising rate and the maximum heat treatment temperature were low, a β-quartz solid solution was precipitated as the main crystal, the average crystal grain size was 70 nm, the transparency was high, and the antiglare property was poor.

Table 2 shows examples (Sample Nos. 6 to 16) of the present invention.

First, the composition is SiO ₂ 65.6%, Al ₂ O ₃ 22.2%, Li ₂ O 3.7%, MgO 0.7%, BaO 1.2%, TiO ₂ 2.0 in mass%. %, ZrO ₂ 2.2%, P ₂ O ₅ 1.4%, Na ₂ O 0.4%, K ₂ O 0.3%, SnO ₂ 0.3%. It was mixed and a glass batch was prepared. Next, using a platinum crucible, the glass batch was melted at 1600 ° C. for 23 hours, further heated to 1650 ° C. and melted for 1 hour. Then, it was poured onto a carbon table, molded to a thickness of 5 mm with a molding roller, and then cooled in a slow cooling furnace at 700 ° C.

Subsequently, the obtained crystalline glass plate was heated from room temperature at a heating rate of 600 ° C./hour, and held at the heat treatment temperature of the first nucleation step in the table for the holding time in the table. The temperature was raised at a heating rate of 600 ° C./hour, and the temperature was maintained at the heat treatment temperature in the second nucleation step for the holding time shown in the table. Then, without lowering the temperature, the temperature is raised from the heat treatment temperature in the second nucleation step to the maximum heat treatment temperature in the table at the rate of temperature rise in the table, and then the glass is held for the holding time in the table to crystallize the glass. A board was made. In addition, the main crystal phase of each sample, average crystal grain size, crystallinity, average linear thermal expansion coefficient, L ^* a ^* b ^* brightness value of the display system L ^* , average transmittance, diffuse reflectance, appearance and antiglare. Was evaluated. The results are shown in the table.

The main crystal phase and crystallinity were evaluated by X-ray diffraction by the powder method using RINT-2100 manufactured by Rigaku. The average crystal grain size was obtained by observing a part of the crystallized glass plate with an electron microscope. The average transmittance and the diffuse reflectance are values measured using a spectrophotometer UV-3100 manufactured by Shimadzu Corporation. The brightness value L ^* of the L ^* a ^* b ^* display system is a value measured by a method conforming to JIS Z8729. A mirror-polished product with a wall thickness of 3.0 mm was used as a measurement sample for the average transmittance, the diffuse reflectance, and the brightness value L ^* of the L ^* a ^* b ^* display system. As for the diffuse reflectance, the incident angle was set to 8 ° and the total reflectance was measured. The average coefficient of linear thermal expansion is a value measured by a differential detection type relative expansion meter in a temperature range of 30 to 750 ° C. The appearance was evaluated by visual observation. Specifically, when each sample was placed on a black background, a case where pale scattered light was observed and transmitted light was observed in yellow was evaluated as an opal tone. The anti-glare property is that when a TiN film having a film thickness of 0.5 μm is formed on one side of each sample by a sputtering method and the side surface on which the TiN film is not formed is illuminated with a 40 W lamp, it is dazzled by direct viewing of reflected light. The case where no feeling of glare was felt was evaluated as "good", and the case where the feeling of glare was felt was evaluated as "bad".

As is clear from Table 2, the sample No. In Nos. 6 to 16, the main crystal phase is a β-spojumen solid solution, the average crystal grain size is 200 to 800 nm, the brightness value L ^* is 36.9 to 72.8, the appearance is opal-like, and the antiglare property is good. It was. Therefore, the sample No. 6 to 16 have a bright luster, are not too conspicuous, and are considered to have a low production cost.

The LAS-based crystallized glass plate according to the present invention has a bright color, and even when the decorative film is formed on the back side, the decorative film is not too conspicuous and the manufacturing cost is low. Therefore, an infrared heating cooker or electromagnetic heating cooking is performed. It is suitable as a top plate of a vessel, and is also suitable as a top plate of a gas cooker. Further, since the LAS-based crystallized glass plate according to the present invention allows light of various indicators to pass through, it can be used for sensor parts other than the top plate for cookers.

Claims (16)

In the method for producing a LAS-based crystallized glass plate containing a β-spodium solid solution as the main crystal phase,
The process of preparing a crystalline glass plate and
The crystalline glass plate is heated to a maximum heat treatment temperature of over 900 ° C. at a heating rate of 300 to 900 ° C./hour, and a β-spojumen solid solution having an average crystal grain size of 100 to 1000 nm is precipitated to LAS. A method for producing a LAS-based crystallized glass plate, which comprises a step of obtaining a system-based crystallized glass plate. The method for producing a LAS-based crystallized glass plate according to claim 1, wherein the holding time at (maximum heat treatment temperature ± 10 ° C.) is less than 60 minutes. The method for producing a LAS-based crystallized glass plate according to claim 1 or 2, wherein a β-spodium solid solution having an average crystal grain size of 150 to 900 nm is precipitated. Claims 1 to 3 characterized by obtaining a LAS-based crystallized glass plate having an L ^* a ^* b ^* display system brightness value L ^* of 30 to 80 in accordance with JIS Z8729 in terms of plate thickness of 3.0 mm. The method for producing a LAS-based crystallized glass plate according to any one of. The LAS-based crystal according to any one of claims 1 to 4, wherein a LAS-based crystallized glass plate having an average transmittance of 10 to 50% at a wavelength of 400 to 800 nm is obtained in terms of a plate thickness of 3.0 mm. A method for manufacturing a glass-ceramic plate. The LAS-based crystallization according to any one of claims 1 to 5, wherein a LAS-based crystallized glass plate having an average transmittance of 50% or more at a wavelength of 800 to 1500 nm is obtained in terms of a plate thickness of 3.0 mm. How to manufacture a glass plate. The invention according to any one of claims 1 to 6, wherein a LAS-based crystallized glass plate having an average coefficient of linear thermal expansion at 30 to 750 ° C. of −10 × 10 ⁻⁷ to + 30 × 10 ⁻⁷ / ° C. is obtained. A method for manufacturing a LAS-based crystallized glass plate. The method for producing a LAS-based crystallized glass plate according to any one of claims 1 to 7, wherein the content of ZnO in the LAS-based crystallized glass plate is less than 2% by mass. LAS-type crystallized glass plate, a composition, in _{mass%, SiO 2 55~75%, Al} 2 O 3 15~30%, Li 2 O 2~6%, 0~3% MgO, BaO 0~5% , ZnO less than _{0~2%, TiO 2 1~6%,} ZrO 2 0~4%, P 2 O 5 0~5%, Na 2 O 0~4%, that it contains K 2 O 0 to 4% The method for producing a LAS-based crystallized glass plate according to any one of claims 1 to 8. The method for producing a LAS-based crystallized glass plate according to any one of claims 1 to 9, wherein the LAS-based crystallized glass plate is used as a top plate for a cooker. A LAS-based crystallized glass plate in which a β-spodium solid solution having an average crystal grain size of 100 to 1000 nm is precipitated, and the brightness of the L ^* a ^* b ^* display system conforming to JIS Z8729 in terms of plate thickness of 3.0 mm. A LAS-based crystallized glass plate having a value L ^* of 30 to 80. The LAS-based crystallized glass plate according to claim 11, wherein the average transmittance at a wavelength of 400 to 800 nm is 10 to 50% in terms of a plate thickness of 3.0 mm. The LAS-based crystallized glass plate according to claim 11 or 12, wherein the average transmittance at a wavelength of 800 to 1500 nm is 50% or more in terms of a plate thickness of 3.0 mm. The LAS-based crystallized glass plate according to any one of claims 11 to 13, wherein the average linear thermal expansion coefficient at 30 to 750 ° C. is −10 × 10 ⁻⁷ to + 30 × 10 ⁻⁷ / ° C. As a composition, in terms of mass%, SiO ₂ 55 to 75%, Al ₂ O ₃ 15 to 30%, Li ₂ O 2 to 6%, MgO 0 to 3%, BaO 0 to 5%, ZnO less than 0 to 2%, _{TiO 2 1~6%, ZrO 2 0~4} %, P 2 O 5 0~5%, Na 2 O 0~4%, claim, characterized in that it contains K 2 O 0~4% 11~ The LAS-based crystallized glass plate according to any one of 14. As a composition, in mass%, SiO ₂ 60 to 70%, Al ₂ O _{3 over} 20 to 30%, Li ₂ O 3 to 5%, MgO 0 to 1%, BaO 1 to 2%, ZnO 0 to 0.4. % _{less, TiO 2 1~4%, ZrO 2} 2~3%, P 2 O 5 0~2%, Na 2 O 0~4%, claims, characterized in that it contains K 2 O 0 to 4% Item 2. The LAS-based crystallized glass plate according to any one of Items 11 to 15.