Method for producing crystallized glass

Abstract

Provided is a method for producing crystallized glass in which cracks are less likely to occur in crystallized glass obtained by peeling after heat-treating a stack of glasses for crystallization while the glasses are in contact with each other.　This method for producing crystallized glass comprises stacking two or more glasses for crystallization being in contact with each other, and subjecting the obtained glass stack for crystallization to a heat treatment including heating at a crystal growth temperature. In the heat treatment, a value of η2 / η1 is 1.0×102 or more, and η2 is 1.0×109 Pa·s or more, wherein η1 is the viscosity of the glasses for crystallization when the crystal growth temperature is reached and η2 is the viscosity thereof when the heating at the crystal growth temperature is finished. Provided that the units for η1 and η2 are Pa·s.

Description

Method for producing crystallized glass

[0001] The present invention relates to a method for producing crystallized glass.

[0002] Crystallized glass is a glass that has various excellent functions. For example, crystallized glass may show excellent strength, and is used in various applications. Crystallized glass is generally obtained by heat-treating glass of a predetermined composition. The glass that is subjected to heat treatment to obtain crystallized glass (hereinafter also referred to as "crystallization glass") may be subjected to heat treatment in a laminated state in order to improve efficiency.

[0003] For example, Patent Document 1 discloses a method of placing a setter having a heat capacity and a density within a predetermined range between crystallization glasses and performing a heat treatment.

[0004] International Publication No. 2020 / 018290

[0005] In the above-mentioned Patent Document 1, a setter is used, but in view of improving productivity, the present inventors have studied a method that does not use a setter. That is, they have studied a method in which crystallization glass is stacked in a state where it is in contact with each other, and then heat-treated. The present inventors have studied a method in which crystallization glass is stacked in a state where it is in contact with each other, and then heat-treated, and then peeled off the crystallization glass after heat-treatment, and have found that cracks may occur in the crystallization glass obtained by peeling off, and that this method needs to be improved.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a method for producing crystallized glass, in which when a stack of glasses for crystallization in contact with each other is heat-treated, cracks are unlikely to occur in the crystallized glass obtained by peeling.

[0007] The present inventors have found that the above problems can be solved by using a glass for crystallization that satisfies certain conditions regarding viscosity during heat treatment, and have arrived at the present invention.

[0008] That is, the inventors have found that the above-mentioned problems can be solved by the following configuration: [1] A method for producing crystallized glass, which comprises stacking two or more pieces of glass for crystallization in contact with each other and subjecting the obtained glass for crystallization laminate to a heat treatment including heating at a crystal growth temperature, wherein in the heat treatment, the viscosity of the glass for crystallization when the crystal growth temperature is reached is η １ and the viscosity at the end of heating at the crystal growth temperature is η ２ When this is done, η ２ / η １ The value is 1.0 x 10 ２ The above, and the above η ２ is 1.0 x 10 ９ A method for producing crystallized glass, wherein the viscosity is η Pa·s or more. １ and the above η ２ The unit of is Pa·s. [2] The above η １ But 1.0 x 10 ９ [3] The method for producing crystallized glass according to [1], wherein the η is less than Pa·s. １ But 1.0 x 10 ７ ~5.0 x 10 ８ [4] The method for producing crystallized glass according to [1] or [2], wherein the η is Pa·s. ２ But 1.0 x 10 １０ ~3.0 x 10 １１ [5] The method for producing crystallized glass according to any one of [1] to [3], wherein the crystal growth temperature is 700 to 1100°C. [6] The composition of the glass for crystallization is expressed in mole percent on an oxide basis as follows: SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, Li ２ The method for producing crystallized glass according to any one of [1] to [5], wherein the glass for crystallization contains 5 to 30% of O. [7] The composition of the glass for crystallization is expressed in mole percent on an oxide basis as follows: SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, P ２ O ５0 to 5%, Li ２ 5-28% O, Na ２ O 0-4%, K ２ O 0-1%, MgO 0-10%, CaO 0-5%, ZrO ２

[0013] A method for producing crystallized glass according to any one of [1] to [6], wherein the glass-ceramics contains 0 to 5% of the above. [8] A method for producing crystallized glass according to any one of [1] to [7], wherein the glass-ceramics contains one or more crystals selected from the group consisting of lithium silicate crystals and lithium aluminosilicate crystals. [9] A method for producing crystallized glass according to any one of [1] to [8], wherein the glass-ceramics contains one or more crystals selected from the group consisting of lithium disilicate crystals, β-spodumene crystals, and petalite crystals.

[10] A method for producing crystallized glass according to any one of [1] to [9], wherein the thickness of the glass-ceramics is 1.5 mm or less.

[11] A method for producing crystallized glass according to any one of [1] to

[10] , wherein the number of glass-ceramics sheets in the glass-ceramics laminate is 5 or more, and the total mass of the glass-ceramics laminate is 20 kg or less.

[12] The method for producing crystallized glass according to any one of [1] to

[11] , wherein the glass for crystallization after the heat treatment is peeled off from the glass for crystallization laminate after the heat treatment to obtain crystallized glass.

[0009] According to the present invention, a method for producing crystallized glass can be provided, in which crystallized glass obtained by heat-treating a stack of glasses to be crystallized in contact with each other and then peeling the stacked glasses is less likely to crack.

[0010] 1 is a cross-sectional schematic diagram showing one embodiment of a glass laminate for crystallization in a manufacturing method of the present invention, and FIG. 2 is a cross-sectional schematic diagram showing one embodiment of a laminate to be subjected to heat treatment of the present invention, and FIG. 3 is a graph in which the horizontal axis represents time in a heat treatment step, the first vertical axis represents heat treatment temperature, and the second vertical axis represents the common logarithm of the viscosity of the glass for crystallization.

[0011] The present invention will be described in detail below. The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, the term "to" indicating a range of numerical values ​​is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0012] In the glass composition, "substantially not containing" means that the glass does not contain any components except for unavoidable impurities contained in raw materials, etc., that is, the glass is not intentionally contained. Specifically, the content of components other than those described as the glass composition is preferably less than 0.1 mol%, more preferably 0.08 mol% or less, and even more preferably 0.05 mol% or less.

[0013] <Method for producing crystallized glass> In the method for producing crystallized glass of the present invention, two or more glasses for crystallization are stacked in contact with each other, and the obtained glass-for-crystallization laminate is subjected to a heat treatment including heating at a crystal growth temperature. In the method for producing crystallized glass of the present invention, in the heat treatment, the viscosity of the glasses for crystallization when the crystal growth temperature is reached is set to η １ and the viscosity at the end of heating at the crystal growth temperature is η ２ When this is done, η ２ / η １ The value is 1.0 x 10 ２ That is all, and η ２ is 1.0 x 10 ９ Pa s or more, provided that η １ and η ２ The unit is Pa·s.

[0014] In the method for producing crystallized glass of the present invention, the mechanism by which cracks are unlikely to occur in the crystallized glass obtained by peeling is not entirely clear, but the inventors speculate as follows: When the crystallized glass is heated at a crystal growth temperature, the viscosity of the crystallized glass is at its lowest at the start of heating. That is, η ２ / η １ The value is 1.0 x 10 ２ Furthermore, the viscosity (η ２ ) to 1.0 × 10９ When the viscosity of the glass for crystallization is Pa·s, the crystallized glass obtained is less likely to stick to itself and is easier to peel off, and as a result, it is thought that cracks are less likely to occur in the crystallized glass obtained by peeling. From the above, it is thought that when the viscosity of the glass for crystallization satisfies the above-mentioned specified requirements, cracks are less likely to occur in the crystallized glass obtained by peeling.

[0015] Hereinafter, each step included in the method for producing crystallized glass of the present invention, and steps that may be included in the method for producing crystallized glass of the present invention will be described in detail. Note that, hereinafter, the step of stacking two or more crystallization glasses in contact with each other to obtain a crystallization glass laminate will also be referred to as a "stacking step". Also, hereinafter, the step of subjecting the crystallization glass laminate to heat treatment, including heating at a crystal growth temperature, will also be referred to as a "heat treatment step". Also, in the method for producing crystallized glass of the present invention, crystallized glass may be obtained by peeling the heat-treated crystallization glass from the heat-treated crystallization glass laminate. Hereinafter, the step of peeling the heat-treated crystallization glass from the heat-treated crystallization glass laminate to obtain crystallized glass will also be referred to as a "peeling step".

[0016] [Lamination step] The lamination step is a step of laminating two or more glasses for crystallization in a state of contact with each other to obtain a glass laminate for crystallization. The glass laminate for crystallization obtained in the lamination step will be described with reference to the drawings.

[0017] FIG. 1 is a cross-sectional schematic diagram showing one embodiment of a crystallized glass laminate in which glasses for crystallization are laminated. The glass laminate 20 for crystallization shown in FIG. 1 is formed by laminating glasses for crystallization 10a, 10b, and 10c in this order. The glasses for crystallization 10a and 10b are in contact with each other. The glasses for crystallization 10b and 10c are in contact with each other. The glasses for crystallization 10a, 10b, and 10c shown in FIG. 1 are plate-shaped glasses. The glass laminate 20 for crystallization shown in FIG. 1 is formed by laminating three glasses for crystallization (glasses for crystallization 10a to 10c) in contact with each other, but the number of glasses for crystallization may be two or more (two or more). For example, the number of glasses for crystallization laminated in the glass laminate for crystallization may be four or more, five or more, or ten or more. Although there is no particular upper limit to the number of stacked sheets, it is preferable to adjust the number of stacked sheets so that the total mass of the stacked glass sheets for crystallization is 30 kg or less. When the total mass of the stacked glass sheets for crystallization is 30 kg or less, the glass sheets for crystallization arranged at the bottom are less likely to break.

[0018] In the lamination process, first, two or more crystallization glasses are prepared. The crystallization glasses are preferably plate-shaped glasses. When the crystallization glasses are plate-shaped glasses, the thickness of the crystallization glasses is not particularly limited, but may be 0.1 mm or more, and preferably 0.5 mm or more. The thickness of the crystallization glasses is often 2.0 mm or less, more preferably 1.5 mm or less, and most preferably 1.0 mm or less. When the crystallization glasses are plate-shaped glasses, the area of ​​the main surface (the surface having the largest area) is not particularly limited, but may be, for example, 0.01 m ２ The above are listed, and 0.1m ２ The area is preferably 0.5 m or more. ２ In many cases, the glass to be crystallized may be float glass produced by the float method or glass produced by the roll-out method. The glass to be crystallized may also be glass produced by other methods.

[0019] In the lamination process, two or more glasses for crystallization are laminated in a state of contact with each other.The lamination method is not particularly limited, and for example, a method of stacking glasses for crystallization in order can be mentioned.In addition, when laminating, the lamination position of the upper glass may be shifted relative to the lower glass, so that it can be used as a gripping part when peeling.

[0020] A preferred composition of the glass for crystallization (hereinafter also referred to as "mother glass composition") will be described below. The preferred composition of the glass for crystallization (mother glass composition) is expressed in mole percentage based on oxides as follows: SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, P ２ O ５ 0 to 5%, Li ２ It is preferable that the glass contains 5 to 30% of O. The mother glass composition of the glass for crystallization is expressed in mole percentage based on oxides as follows: SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, Li ２ It is more preferable that the O content is 5 to 30%.

[0021] Among them, the mother glass composition is expressed as mole percentage based on oxides: SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, P ２ O ５ 0 to 5%, Li ２ 5-28% O, Na ２ O 0-4%, K ２ O 0-5%, MgO 0-10%, CaO 0-5%, ZrO ２ The content of each component in the mother glass composition is preferably 0 to 5%.

[0022] SiO ２ is a component that forms the glass network. It also increases chemical durability and reduces the occurrence of cracks when the glass surface is scratched.

[0023] SiO ２In order to improve chemical durability, the content of SiO is more preferably 63% or more, and even more preferably 65% ​​or more. ２ The content is more preferably 74.0% or less, and further preferably 72.0% or less.

[0024] Al ２ O ３ is a component that improves the ion exchange performance during chemical strengthening and increases the surface compressive stress after strengthening. It also contributes to the formation of crystals containing Al and Li. From the viewpoint of obtaining the above effects, Al ２ O ３ The content of Al is more preferably 2.5% or more, and even more preferably 3.0% or more and 3.5% or more, in that order. On the other hand, there are also cases where it is required that crystals do not grow easily during melting, that devitrification defects do not occur easily, leading to a higher yield, and that the high-temperature viscosity of the glass is reduced to make it easier to melt. From these viewpoints, Al ２ O ３ The content of is more preferably 18.0% or less, further preferably 17.0% or less, 16.0% or less, and 15.0% or less, in that order.

[0025] SiO ２ and Al ２ O ３ These are all components that stabilize the glass structure. ２ and Al ２ O ３ The total content of SiO is preferably 64.0% or more, more preferably 68.0% or more, even more preferably 72.0% or more, and particularly preferably 76.0% or more. ２ and Al ２ O ３ Both of these tend to increase the melting temperature of the glass. ２ and Al ２ O ３ The total content of is preferably 90.0% or less, more preferably 88.0% or less, and even more preferably 86.0% or less.

[0026] Li ２O is a component capable of ion exchange and improves the melting property of the glass. ２ By containing O, Li ions on the glass surface are ion-exchanged with external Na ions to be incorporated into the glass, and the incorporated Na ions are then ion-exchanged with external K ions, which makes it easy to obtain a stress profile with a large surface compressive stress and a thick compressive stress layer. ２ By including O, it is easy to obtain crystallized glass when a specific heat treatment is performed. ２ The O content is more preferably 7.0% or more, and further preferably 9.0%.

[0027] On the other hand, in order to reduce the crystal growth rate during glass molding and to prevent deterioration of quality due to devitrification, Li ２ The O content is more preferably 27.0% or less, further preferably 25.0% or less, particularly preferably 23.0% or less, most preferably 21.0% or less, and may be 20.0% or less.

[0028] Na ２ O and K ２ O is a component that improves the meltability of the glass and reduces the crystal growth rate during glass molding. It is also preferable to include a small amount of O in order to improve the ion exchange performance.

[0029] Na ２ O is a component that can be ion-exchanged in chemical strengthening treatment using potassium salts, and also a component that reduces the viscosity of glass. ２ The content of O is preferably 0.3% or more, more preferably 0.5% or more, and more preferably 0.8% or more, in that order. On the other hand, from the viewpoint of maintaining the glass network and avoiding a decrease in the surface compressive stress (Na_CS) in the strengthening treatment with a sodium salt, Na ２ The O content is more preferably 3.0% or less, further preferably 2.5% or less, and particularly preferably 2.3% or less.

[0030] K ２ O is a component that suppresses the rise in devitrification temperature to suppress devitrification and also improves ion exchange performance. ２The content of O is more preferably 0.03% or more, further preferably 0.05% or more, and particularly preferably 0.1% or more. On the other hand, from the viewpoint of avoiding a decrease in the surface compressive stress (K_CS) in the strengthening treatment using a sodium salt, K ２ The content of O is preferably 1.0% or less, more preferably 0.8% or less, and further preferably 0.5% or less. ２ O may not be substantially contained.

[0031] Li ２ O content, Na ２ O content and K content ２ The total content of O, R, is preferably 8.0 to 30.0%, more preferably 9.0 to 28.0%, and particularly preferably 10.0 to 25.0%, from the viewpoint of suppressing an increase in the devitrification temperature and reducing the crystal growth rate.

[0032] Li for the above R ２ The ratio of the content of O ([Li ２ O] / ([Li ２ O] + [Na ２ O] + [K ２ O]), hereinafter referred to as “Li ２ O / R ２ From the viewpoint of further improving the deep layer stress in the chemical strengthening characteristics, Li is more preferably 0.80 or more, and even more preferably 0.85 or more. ２ O / R ２ From the viewpoint of further improving chemical resistance, O is more preferably 0.99 or less, further preferably 0.98 or less, and particularly preferably 0.95 or less.

[0033] Na for the above R ２ The ratio of the content of O ([Na ２ O] / ([Li ２ O] + [Na ２ O] + [K ２ O]), hereinafter referred to as “Na ２ O / R ２ From the viewpoint of further improving the deep layer stress in the chemical strengthening characteristics, Na is preferably more than 0.00, more preferably 0.01 or more, even more preferably 0.02 or more, particularly preferably 0.05 or more, and most preferably 0.06 or more. ２O / R ２ From the viewpoint of further improving chemical resistance, O is preferably 0.40 or less, more preferably 0.30 or less, even more preferably 0.20 or less, and particularly preferably 0.10 or less.

[0034] K for the above R ２ The ratio of the content of O ([K ２ O] / ([Li ２ O] + [Na ２ O] + [K ２ O]), hereinafter referred to as “K ２ O / R ２ From the viewpoint of further increasing the electrical resistance of the glass, K is preferably 0.001 or more, more preferably 0.004 or more, and even more preferably 0.01 or more. ２ O / R ２ From the viewpoint of increasing the compressive stress near the surface in chemical strengthening properties, O is preferably 0.50 or less, more preferably 0.40 or less, further preferably 0.30 or less, and particularly preferably 0.20 or less. ２ O / R ２ O may be 0.

[0035] Also, Li ２ O / R ２ O and Na ２ O / R ２ O and K ２ O / R ２ From the viewpoint of suppressing an increase in the devitrification temperature and reducing the crystal growth rate, the product with O is preferably 0.00005 or more, more preferably 0.0001 or more, and even more preferably 0.001 or more. Moreover, the product is more preferably 0.020 or less. The product may be 0.

[0036] Al relative to the above R ２ O ３ The ratio of the content of ([Al ２ O ３ ] / ([Li ２ O] + [Na ２ O] + [K ２ O]), hereinafter referred to as “Al ２ O ３ / R ２Al is preferably 0.10 or more, more preferably 0.20 or more, even more preferably 0.50 or more, and particularly preferably 0.80 or more. ２ O ３ / R ２ O is preferably 3.00 or less, more preferably 2.00 or less, even more preferably 1.50 or less, and particularly preferably 1.30 or less.

[0037] [Al ２ O ３ ]-[Na ２ O]-[K ２ O] + [Li ２ The value represented by [Ratio of % to % of the total mass of the sintered body] is preferably 15.0% or more, more preferably 20.0% or more. The value is preferably 35.0% or less, more preferably 30.0% or less.

[0038] MgO may be contained to reduce viscosity during dissolution, etc. The MgO content is more preferably 0.05% or more, and even more preferably 0.08% or more. On the other hand, in order to easily increase the compressive stress layer during chemical strengthening treatment, the MgO content is more preferably 9.0% or less, and even more preferably 7.0% or less, 5.0% or less, and 3.0% or less, in that order.

[0039] Furthermore, by including MgO, it is possible to suppress the phase transition of the crystal phase from β-quartz solid solution to β-spodumene, and to suppress the precipitation of β-spodumene crystals. From the above viewpoint, it is also preferable that MgO is included in an amount of more than 0.5% and not more than 7.0%. MgO may not be substantially included.

[0040] CaO is a component that improves the meltability of glass and may be contained. The CaO content is more preferably 0.005% or more, and even more preferably 0.01% or more. On the other hand, in terms of the tendency to increase the compressive stress value during chemical strengthening treatment, the CaO content is more preferably 2.0% or less, even more preferably 1.0% or less, particularly preferably 0.8% or less, and most preferably 0.5% or less. CaO may not be substantially contained.

[0041] In order to increase the stability of the glass, it is more preferable to contain at least one of MgO and CaO, and even more preferable to contain MgO. The total content of MgO and CaO is preferably 0.01% or more, more preferably more than 0.05%, even more preferably 0.1% or more, and particularly preferably 0.2% or more. In order to further improve chemical strengthening properties, the total content of MgO and CaO is preferably 10.0% or less, more preferably 8.0% or less, 7.0% or less, 6.0% or less, 3.0% or less, and 1.0% or less, in that order.

[0042] SrO is a component that improves the meltability of glass and may be contained. The content of SrO is more preferably 0.1% or more, even more preferably 0.15% or more, and particularly preferably 0.5% or more. In order to facilitate increasing the compressive stress value during chemical strengthening treatment, the content of SrO is more preferably 3.0% or less, even more preferably 2.0% or less, particularly preferably 1.0% or less, and most preferably 0.5% or less. SrO may not be substantially contained.

[0043] BaO is a component that improves the meltability of glass and may be contained. When BaO is contained, the content is preferably 0.1% or more, more preferably 0.15% or more, and even more preferably 0.5% or more. In order to make it easier to increase the compressive stress value during chemical strengthening treatment, the content of BaO is preferably 3.0% or less, more preferably 2.0% or less, even more preferably 1.0% or less, and particularly preferably 0.5% or less. BaO may not be substantially contained.

[0044] ZnO is a component that improves the meltability of glass. The ZnO content is more preferably 0.1% or more, even more preferably 0.15% or more, and particularly preferably 0.5% or more. In order to facilitate increasing the compressive stress value during chemical strengthening treatment, the ZnO content is more preferably 3.0% or less, even more preferably 2.0% or less, particularly preferably 1.0% or less, and most preferably 0.5% or less. ZnO may not be substantially contained.

[0045] InW is a parameter that represents the degree of oxide mixing, calculated from the contents of alkali metal oxides, alkaline earth metal oxides, and zinc oxide contained in glass. InW is expressed by the following formula: InW = In(([Li ２ O] + [Na ２ O] + [K ２ O] + [MgO] + [CaO] + [SrO] + [BaO] + [ZnO])! / ([Li ２ O]! × [Na ２ O]! × [K ２ O]! × [MgO]! × [CaO]! × [SrO]! × [BaO]! × [ZnO]!)) ... Formula (W1) In formula (W1), [Li ２ O], [Na ２ O], [K ２ O], [MgO], [CaO], [SrO], [BaO] and [ZnO] are LiO, ２ O, Na ２ O.K. ２ The formula represents the content of each component of O, MgO, CaO, SrO, BaO, and ZnO expressed as mole percentage based on oxide. The symbol ! indicates a factorial of a positive integer. For example, [XO]! is the factorial of the mole percentage content of component XO expressed as mole percentage based on oxide, rounded down to the nearest integer. For example, Na ２ When O is 4.8 mol%, the calculation is made by factoring "4", that is, 4 x 3 x 2 x 1. The larger the value of lnW, the higher the degree of mixing of the above metal oxides, and the more effectively devitrification of the glass can be suppressed. From the above viewpoints, lnW is preferably 10 or more, more preferably 12 or more, even more preferably 13 or more, and particularly preferably 14 or more. lnW is preferably 20 or less, more preferably 18 or less, and even more preferably 17 or less.

[0046] TiO ２ is a component that is highly effective in suppressing solarization of glass and is a material that forms the nuclei of crystals, so it may be contained. ２ When TiO is contained, the content is preferably 0.03% or more, more preferably 0.05% or more, and further preferably 0.08% or more.２ has light absorption properties, so from the viewpoint of preventing color development of glass, TiO ２ The content of TiO is preferably 2.5% or less, more preferably 2.0% or less, further preferably 1.5% or less, and particularly preferably 1.0% or less. ２ may not be substantially included.

[0047] ZrO ２ is a component that makes it easy to increase the surface compressive stress of chemically strengthened glass-ceramics. In addition, ZrO is a material that forms the nucleus of crystals. ２ It may contain ZrO ２ The content of ZrO is more preferably more than 0%, and further preferably 0.5% or more, 1% or more, and 1.5% or more, in the following order. ２ The content is more preferably 4% or less.

[0048] P ２ O ５ P tends to increase the compressive stress layer during chemical strengthening. ２ O ５ The content of P is more preferably 0.5% or more, further preferably 1.0% or more, and particularly preferably 1.5% or more. ２ O ５ The content of is more preferably 3.0% or less. From the viewpoint of preventing the occurrence of striae during melting, it is also preferable that it is substantially not contained.

[0049] B ２ O ３ reduces the brittleness of the glass and improves the crack resistance, or improves the meltability of the glass. ２ O ３ The content of B is preferably 0.5% or more, more preferably 1.0% or more, and even more preferably 2.0% or more. ２ O ３ The content of B is preferably 8.0% or less. ２ O ３The content of is more preferably 6.0% or less, further preferably 4.0% or less, and particularly preferably 2.0% or less. From the viewpoint of preventing the occurrence of striae during melting, it is also preferable that it is substantially not contained.

[0050] Y ２ O ３ is a component that makes it easier to increase the surface compressive stress of the chemically strengthened glass-ceramics while slowing down the crystal growth rate. ２ O ３ The content of Y is preferably more than 0%, and more preferably 0.1% or more, 0.2% or more, 0.5% or more, and 0.8% or more in the following order. ２ O ３ The content of Y is more preferably 2.0% or less, and further preferably 1.5% or less. ２ O ３ may not be substantially included.

[0051] From the viewpoint of improving the initial solubility, ZrO ２ and Y ２ O ３ The total content of ZrO is more preferably 5.0% or less. ２ and Y ２ O ３ Although there is no particular lower limit for the total content, from the viewpoint of increasing the strength of the glass, it is more preferably 0.5% or more, and further preferably 1.0% or more and 1.5% or more, in that order.

[0052] ZrO ２ and Y ２ O ３ ZrO relative to the total content of ２ The ratio of the content of [ZrO ２ ] / ([ZrO ２ ]+[Y ２ O ３ ]) is more preferably 0.50 or more, further preferably 1.00 or more, and particularly preferably 2.00 or more. ２ ] / ([ZrO ２ ]+[Y ２ O ３]) is more preferably 8.00 or less, even more preferably 7.00 or less, and particularly preferably 6.00 or less.

[0053] ZrO ２ and Y ２ O ３ is known as a nucleating agent when added alone, but ZrO ２ and Y ２ O ３ By co-adding with ZrO ２ and Y ２ O ３ Since a eutectic of [ZrO ２ ] / ([ZrO ２ ]+[Y ２ O ３ By setting [ZrO ] within the above range, the diffusion of ions in the glass is suppressed, the increase in the devitrification temperature is suppressed, and devitrification can be suppressed. ２ ] / ([ZrO ２ ]+[Y ２ O ３ By setting [ZrO ] within the above range, the glass is stabilized, and further, the temperature ranges where nucleation occurs and the temperature ranges where crystal growth occurs are separated without overlapping, suppressing an increase in the crystal growth rate, and thus suppressing the occurrence of defects. ２ ] / ([ZrO ２ ]+[Y ２ O ３ By setting the temperature range at which nucleation occurs to the lower side, the decrease in the crystallization initiation temperature is suppressed, and manufacturing characteristics can be improved.

[0054] La ２ O ３ is not required, but Y ２ O ３ It can be contained for the same reasons as above. ２ O ３ is preferably 0.1% or more, more preferably 0.2% or more, further preferably 0.5% or more, particularly preferably 0.8% or more. On the other hand, if the content is too high, it becomes difficult to increase the compressive stress layer during chemical strengthening treatment. ２ O ３is preferably 5.0% or less, more preferably 3.0% or less, even more preferably 2.0% or less, and particularly preferably 1.5% or less. ２ O ３ It is also preferable that the material is substantially free of

[0055] Nb ２ O ５、 Ta ２ O ５ , Gd ２ O ３ , CeO ２ is a component that has the effect of suppressing solarization of the glass and improving meltability, and may be contained. When these components are contained, the content of each is preferably 0.03% or more, more preferably 0.1% or more, even more preferably 0.5% or more, particularly preferably 0.8% or more, and most preferably 1.0% or more. On the other hand, it is preferably 3.0% or less, more preferably 2.0% or less, and even more preferably 1.0% or less.

[0056] Fe ２ O ３ Since Fe absorbs heat rays, it has the effect of improving the meltability of glass, and is preferably contained when mass-producing glass using a large melting furnace. In this case, the content is preferably 0.002% or more, more preferably 0.005% or more, even more preferably 0.007% or more, and particularly preferably 0.01% or more, expressed in mass% on an oxide basis. On the other hand, Fe ２ O ３ Since an excessive content of causes coloration, from the viewpoint of enhancing the transparency of the glass, the content thereof, expressed as mass% on an oxide basis, is preferably 0.3% or less, more preferably 0.04% or less, even more preferably 0.025% or less, and particularly preferably 0.015% or less.

[0057] Furthermore, other coloring components may be added within a range that does not impede the achievement of desired chemical strengthening properties, etc. Examples of other coloring components include Co. ３ O ４ , MnO ２ , NiO, CuO, Cr ２ O ３ , V ２ O５ , Bi ２ O ３ , SeO ２ , Er ２ O ３ , Nd ２ O ３ The following are suitable examples.

[0058] SO is used as a fining agent when melting glass. ３ , chloride, fluoride, etc. may be contained as appropriate. ２ O ３ It is preferable that Sb is not contained. ２ O ３ When SnO is contained, it is preferably 0.3% or less, more preferably 0.1% or less, and most preferably not contained. ２ The content of SnO is more preferably 0.1% or more, further preferably 0.2% or more, and particularly preferably 0.3% or more. ２ In order to suppress the occurrence of defects, the content is preferably 1.5% or less, and more preferably 1.2% or less.

[0059] The glass for crystallization satisfies a predetermined requirement regarding viscosity in the heat treatment step described below.

[0060] [Heat treatment process] In the heat treatment process, the glass laminate for crystallization is subjected to heat treatment including heating at a crystal growth temperature to obtain crystallized glass. Note that the heat treatment process only needs to include heating at a crystal growth temperature (hereinafter also referred to as "crystal growth treatment"). The heat treatment process may also include heating at a nucleation temperature (hereinafter also referred to as "nucleation treatment"). The heat treatment process can be carried out, for example, by heating the laminate of the embodiment shown in Fig. 2.

[0061] Fig. 2 is a cross-sectional schematic diagram showing one embodiment of a laminate to be subjected to a heat treatment process. The laminate 30 shown in Fig. 2 has, in this order, a first setter plate 22, a glass laminate for crystallization 20, a second setter plate 24, and a support 26. The glass laminate for crystallization 20 is the same as the glass laminate for crystallization 20 described in Fig. 2 , and therefore a description thereof will be omitted. The support 26 supports the glass laminate for crystallization 20 and facilitates transportation, etc. Furthermore, the arrangement of the first setter plate 22 and the second setter plate 24 makes it difficult for the glass for crystallization 12 in the glass laminate for crystallization 20 to shift position.

[0062] 2, any one or more of the first setter plate 22, the second setter plate 24, and the support 26 may be omitted. The first setter plate 22, the second setter plate 24, and the support 26 are preferably formed of a known heat-resistant material.

[0063] In the heat treatment step, heating at a crystal growth temperature (crystal growth treatment) is carried out, and the heating temperature in the crystal growth treatment can be appropriately adjusted according to the type of crystals to be precipitated in the glass for crystallization.For example, the heating temperature in the crystal growth treatment is preferably 600°C or higher, more preferably 700°C or higher, even more preferably 800°C or higher, and may be 900°C or higher.The heating temperature in the crystal growth treatment is usually 1100°C or lower.The heating time in the crystal growth treatment can be, for example, 0.2 hours or higher, preferably 0.5 hours or higher, more preferably 1.0 hours or higher, and even more preferably 1.5 hours or higher.In addition, the heating time in the high-temperature heat treatment can be 12 hours or lower, preferably 6 hours or lower, and more preferably 4 hours or lower.

[0064] Furthermore, as described above, the heat treatment step may include a treatment of heating at a nucleation temperature (nucleation treatment). The nucleation treatment is preferably carried out before the crystal growth treatment. More specifically, it is preferable to carry out the crystal growth treatment after carrying out the nucleation treatment on the glass for crystallization. Furthermore, it is preferable to carry out the nucleation treatment at a temperature lower than the temperature at which the crystal growth treatment is carried out. When nucleation is carried out, crystal nuclei are generated in the glass for crystallization, and when crystal growth treatment is carried out, the crystal nuclei tend to grow. The heating temperature in the nucleation treatment can be appropriately adjusted, for example, depending on the type of crystal to be precipitated in the glass for crystallization. For example, the heating temperature in the nucleation treatment may be 500°C or higher, preferably 600°C or higher, and more preferably 700°C or higher. Furthermore, the heating temperature in the nucleation treatment is preferably less than 800°C, more preferably 795°C or lower. The heating time in the nucleation treatment may be, for example, 0.5 hours or more, preferably 1 hour or more, and more preferably 2 hours or more. The heating time for the nucleation treatment may be 12 hours or less, preferably 8 hours or less, and more preferably 6 hours or less.

[0065] The type of crystal contained in the obtained crystallized glass is not particularly limited, but for example, one or more crystals selected from the group consisting of lithium silicate crystals, lithium aluminosilicate crystals, and lithium phosphate crystals are preferred, and one or more crystals selected from the group consisting of lithium silicate crystals and lithium aluminosilicate crystals are more preferred. As the lithium silicate crystals, lithium metasilicate (Li ２ SiO ３ ) crystal, lithium disilicate crystal (Li ２ Si ２ O ５ As the lithium phosphate crystal, lithium orthophosphate crystal (Li ３ P.O. ４ As the lithium aluminosilicate crystal, β-spodumene crystal (LiAlSi ２ O ６ ), petalite crystals (LiAlSi ４ O １０) and the like are preferred. The resulting crystallized glass also preferably contains one or more crystals selected from the group consisting of lithium disilicate crystals, β-spodumene crystals, and petalite crystals. Crystals contained in the resulting crystallized glass also include β-quartz solid solution, magnesium-containing crystals, and zirconium-containing crystals.

[0066] The crystallization rate of the resulting crystallized glass is preferably 10% or more, more preferably 15% or more, even more preferably 20% or more, and particularly preferably 25% or more, in terms of improving mechanical strength. Furthermore, in order to increase transparency, it is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less. A small crystallization rate is also advantageous in that it is easy to heat and bend. The crystallization rate can be calculated from X-ray diffraction intensity by the Rietveld method. The Rietveld method is described in "Crystal Analysis Handbook," edited by the Editorial Committee of the Crystallographic Society of Japan (Kyoritsu Shuppan, 1999, pp. 492-499).

[0067] The average particle size of the precipitated crystals of the obtained crystallized glass is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and particularly preferably 100 nm or less, in order to improve transparency. The average particle size of the precipitated crystals can be determined from a transmission electron microscope (TEM) image. It can also be estimated from a scanning electron microscope (SEM) image.

[0068] In the heat treatment step, the temperature increase rate when changing the temperature can be adjusted as appropriate, but is, for example, 1°C / min or more, preferably 3°C / min or more. The temperature increase rate is, for example, 10°C / min or less. The atmosphere in the heat treatment step is not particularly limited, and may be an inert gas atmosphere or an air atmosphere.

[0069] The heat treatment step can be carried out in a known heat treatment furnace or the like. The type of the heat treatment furnace is not particularly limited, and may be a batch type or a continuous type. The heating type of the heat treatment furnace is also not particularly limited, and may be a combustion heating type or an electric heating type.

[0070] In the heat treatment step of the present invention, as described above, the viscosity of the glass for crystallization when it reaches the temperature at which the crystal growth treatment is performed (crystal growth temperature) is set to η １ and the viscosity at the end of the crystal growth process is η ２ Then, η ２ / η １ The value is 1.0 x 10 ２ That's all. Also, η ２ is 1.0 x 10 ９ Hereinafter, with reference to the drawings, an example of the temperature scheme of the heat treatment step and the change in viscosity at that temperature will be described.

[0071] 3 is a graph in which the horizontal axis represents the time in the heat treatment process, the first vertical axis represents the heat treatment temperature, and the second vertical axis represents the common logarithm of the viscosity of the glass for crystallization. In FIG. 3, the dotted line represents the temperature profile, and the first vertical axis (left vertical axis) is referred to. Also, in FIG. 3, the solid line represents the change in viscosity, and the second vertical axis (right vertical axis) is referred to. In the scheme of the heat treatment process in the graph shown in FIG. 3, first, the time t １ From time t ２ The temperature is increased at a predetermined rate until the temperature reaches T １ Then, at time t ３ Up to temperature T １ Furthermore, the time t ３ From time t ４ The temperature is increased at a predetermined rate until the temperature reaches T ２ Then, at time t ５ Up to temperature T ２ The temperature is maintained at T ２ After holding at t ６ The temperature is lowered at a predetermined rate during the time t ２ From time t ３ Temperature T １ The heat treatment at time t ４ From time t ５ Temperature T ２ The heat treatment in step 1 corresponds to the above-mentioned crystal growth treatment.

[0072] Here, as shown in FIG. 3, the temperature T１ In the nucleation process at , the viscosity of the crystallization glass is η ０ In addition, the temperature T ２ The time t until ３ From time t ４ During this time, the viscosity is η １ The temperature drops to T ２ While holding at , the viscosity is η ２ In the heat treatment process of the present invention, η ２ / η １ The value is 1.0 x 10 ２ or more, and η ２ The value is 1.0 x 10 ９ It is Pa·s or more.

[0073] The crystal growth treatment refers to a treatment in which heat treatment is carried out at the above crystal growth temperature, and any heat treatment at a temperature at which crystals grow in the glass for crystallization is considered to be a crystal growth treatment. １ indicates the viscosity when the crystal growth temperature is reached. The crystal growth treatment may be divided into two or more steps, but the end of the crystal growth treatment refers to the time when the temperature starts to drop from the temperature of the last heat treatment at the crystal growth temperature. ２ indicates the viscosity at the time when the temperature starts to decrease from the temperature of the last heat treatment at the crystal growth temperature. Here, the crystal growth temperature is measured by the following method. The crystal growth temperature is defined as the temperature at which a peak corresponding to the crystal peak appears in a DSC curve obtained using a differential scanning calorimeter.

[0074] In this specification, the above η １ and η ２ is measured by the following method: １ For η, the viscosity at the crystallization onset temperature is measured using the penetration method on the glass before crystallization. ２For the above, the viscosity of the crystallized glass is measured at the crystallization onset temperature using the above-mentioned penetration method. For the above-mentioned penetration method, see Shiraishi et al., "Development of a wide-range viscometer by combining the penetration method, parallel plate deformation and rotation peak," Journal of the Japan Institute of Metals, Vol. 60, No. 2, pp. 184-191, 1996.

[0075] η １ is 1.0 x 10 ９ Preferably less than 7.0 x 10 Pa s ８ Pa s or less is more preferable, and 5.0 × 10 ８ Pa s or less is more preferable. １ is 1.0 x 10 ６ Pa s or more is preferable, and 1.0 × 10 ７ Pa·s or more is more preferable. ２ is 5.0 × 10 in that the strength of the resulting crystallized glass is superior. ９ Pa s or more is preferable, and 1.0 × 10 １０ Pa s or more is more preferable, and 3.0 × 10 １０ Pa s or more is more preferable. ２ is 1.0 x 10 １３ Pa s or less is preferable, and 3.0 × 10 １１ Pa·s or less is more preferable.

[0076] Above η １ can be adjusted by the composition of the glass for crystallization, the nucleation temperature, the nucleation time, etc. ２ can be adjusted by the composition of the crystallization glass, the crystal growth temperature, the crystal growth time, and the like.

[0077] [Peeling process] Peeling process is the process of peeling adjacent crystallized glass from each other.As mentioned above, in the production of the crystallized glass of the present invention, crystallized glass is not easily stuck together, so crystallized glass is easily peeled from each other.By carrying out peeling process, crystallized glass is obtained by crystallizing the above-mentioned crystallized glass.Peeling process can be carried out by known method, for example, the crystallized glass of the crystallized glass laminate after heat treatment is pulled in the direction approximately parallel to the lamination direction, and the crystallized glass is peeled off after crystallization.

[0078] [Cutting step] The manufacturing method of the crystallized glass of the present invention may have a step of cutting the crystallized glass obtained into desired size. That is, the crystallized glass obtained may be cut. There is no particular limitation on the cutting method, and it can be cut by a known method. There is no particular limitation on the size of the crystallized glass cut, and it can be cut into desired size.

[0079] [Other Steps] The method for producing crystallized glass of the present invention may have other steps than those described above. For example, it may have a chamfering step of chamfering the cut crystallized glass. It may also have a forming step of bending the obtained crystallized glass. It may also have a polishing step of polishing the surface of the obtained crystallized glass.

[0080] Furthermore, the crystallized glass obtained by the method for producing crystallized glass of the present invention may be subjected to a chemical strengthening treatment. That is, the method for producing crystallized glass of the present invention may include a chemical strengthening treatment step in which the obtained crystallized glass is chemically strengthened. The chemical strengthening treatment step can be carried out by a known method. For example, the chemical strengthening treatment is carried out by contacting the crystallized glass with a molten salt of a metal salt (e.g., potassium nitrate or sodium nitrate) containing a metal ion with a large ionic radius (typically, K ion or Na ion). The contact between the crystallized glass and the molten salt of the metal salt is carried out, for example, by immersing the crystallized glass in the molten salt of the metal salt. Upon contact between the crystallized glass and the metal salt, metal ions with a small ionic radius (typically, Na ion or Li ion) in the crystallized glass are replaced with metal ions with a large ionic radius (typically, K ion for Na ion, and Na ion or K ion for Li ion). Examples of the molten salt include a molten salt containing at least one of sodium nitrate and potassium nitrate. The chemical strengthening treatment may be carried out in two or more stages.

[0081] Generally, the crystallization heat treatment of the crystallized glass is carried out in a continuous or batch type electric furnace, but it is also possible to carry out the crystallization heat treatment simultaneously with the heating and bending process in the bending machine. ２But 1.0 x 10 １１ Pa・s or more 1.0×10 １２．５ It is also preferable that the viscosity is Pa·s or less.

[0082] <Applications> The crystallized glass obtained by the crystallized glass manufacturing method of the present invention can be used in a variety of applications. In particular, the crystallized glass obtained is useful as a cover glass. The cover glass can also be suitably used for purposes such as surface protection of displays and solar cell modules. In particular, the crystallized glass that has been chemically strengthened is useful as a cover glass for mobile devices such as mobile phones, smartphones, personal digital assistants (PDAs), and tablet terminals. Furthermore, it is also useful as a cover glass for non-portable display devices such as televisions (TVs), personal computers (PCs), and touch panels; a cover glass for the surface of a solar cell module; an elevator wall; a wall surface (full-surface display) of a building such as a house or building; a window glass; and construction materials such as tabletops and the interior of an automobile or airplane. It is also useful as a cover glass for the above-mentioned items. Furthermore, it can be used for applications such as a curved housing by bending.

[0083] The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the examples shown below. Examples 1 and 2 described below are examples, and Example 3 described below is a comparative example.

[0084] Example 1 First, glass raw materials were mixed and melted to obtain the glass compositions shown in Table 1, expressed in mole percentages based on oxides, and a glass plate having a thickness of 0.6 mm was obtained by the float method. The obtained glass plate was cut into a size of 50 mm x 50 mm to prepare glass for crystallization. The oxides, hydroxides, carbonates, nitrates, etc. used as the glass raw materials were appropriately selected from commonly used glass raw materials.

[0085] [Glass composition] SiO ２ : 70.00% Al２ O ３ : 14.15% P ２ O ５ : 1.50% Li ２ O: 10.05% Na ２ O: 1.00% K ２ O: 0.50% MgO: 0.10% CaO: 0.10% TiO ２ : 0.10% ZrO ２ : 1.50% SnO ２ : 1.00%

[0086] Next, ten glass plates of the obtained glass for crystallization were stacked to obtain a glass laminate for crystallization. The obtained glass laminate for crystallization was further placed on an alumina plate as a support to obtain a laminate, and the laminate was introduced into a heat treatment furnace (MBK furnace manufactured by Tokyo Motoyama Shokai Co., Ltd.).

[0087] The heat treatment in the heat treatment furnace was performed by heating at 790°C for 4 hours (corresponding to the nucleation treatment) followed by heating at 920°C for 3 hours (corresponding to the crystal growth treatment). The temperature increase and decrease rates were controlled to 5°C / min. The atmosphere for the heat treatment in the heat treatment furnace was air. Here, the viscosity of the glass for crystallization at the start of the crystal growth treatment, η １ was measured by the above-mentioned method, and found to be 3.2 × 10 ８ The viscosity of the glass-ceramic at the end of the crystal growth treatment was η ２ was measured by the above-mentioned method, and found to be 3.2 × 10 １０ Pa s. That is, η ２ / η １ The value of is 1.0 x 10 ２ It was.

[0088] The crystallized glass obtained by the heat treatment was peeled off one by one to obtain crystallized glass. ２ O ６) crystals were precipitated, and the crystallization rate was 70%. In the above procedure, the crystallized glass could be peeled off one by one. Furthermore, of the crystallized glass that was peeled off one by one, no crystallized glass had cracks. The type of crystals precipitated in the crystallized glass was identified and the crystallization rate was calculated by powder X-ray diffraction measurement under the following conditions. - Measurement device: SmartLab manufactured by Rigaku Corporation - X-ray used: CuKα ray - Measurement range: 2θ = 10 to 80° - Scan speed: 10° / min - Scan step: 0.02°

[0089] Example 2: In the procedure of Example 1, except that the glass for crystallization used was glass of the following composition, the glass for crystallization was laminated and heat-treated in the same manner as in Example 1, to obtain crystallized glass, except that the heating temperature in the nucleation treatment was changed to 550°C, and the heating temperature in the crystal growth treatment was changed to 850°C.

[0090] Here, η is the viscosity of the glass for crystallization when the crystal growth treatment is started. １ was measured by the above-mentioned method, and found to be 3.2 × 10 ７ The viscosity of the glass-ceramic at the end of the crystal growth treatment was η ２ was measured by the above-mentioned method, and found to be 1.0 × 10 １１ Pa s. That is, η ２ / η １ The value of is 3.2 × 10 ３ It was.

[0091] In the procedure of Example 2, the crystallized glass could be peeled off one by one. Furthermore, among the crystallized glass that was peeled off one by one, no crystallized glass had cracks.

[0092] [Glass composition] SiO ２ : 69% Al ２ O ３ : 4.1% P ２ O ５ : 1.0% Li ２ O: 21% Na ２ O: 1.5% K ２O: 0% MgO: 0% CaO: 0% TiO ２ : 0% ZrO ２ : 1.7% SnO ２ : 0.1% B ２ O ３ : 1.6%

[0093] Example 3: In the procedure of Example 1, except that the glass for crystallization used was glass of the following composition, the glass for crystallization was laminated and heat-treated in the same manner as in Example 1, to obtain crystallized glass, except that the heating temperature in the nucleation treatment was changed to 550°C, and the heating temperature in the crystal growth treatment was changed to 700°C.

[0094] Here, η is the viscosity of the glass for crystallization when the crystal growth treatment is started. １ was measured by the above-mentioned method, and found to be 1.0 × 10 ８ The viscosity of the glass-ceramic at the end of the crystal growth treatment was η ２ was measured by the above-mentioned method, and found to be 3.2 × 10 ８ Pa s. That is, η ２ / η １ The value of is 3.2 × 10 ０ It was.

[0095] In the procedure of Example 3, when trying to peel off the crystallized glass one by one, cracks occurred in the crystallized glass. Of the crystallized glass that was peeled off, 10 crystallized glass sheets had cracks.

[0096] [Glass composition] SiO ２ : 61% Al ２ O ３ : 5% P ２ O ５ : 2% Li ２ O: 21% Na ２ O: 2% K ２ O: 0% MgO: 5% CaO: 0% TiO ２ : 0% ZrO ２ : 3% SnO ２ : 0% Y ２ O ３ : 1%

[0097] From the above results, the method for producing crystallized glass of the present invention is to laminate two or more pieces of glass for crystallization in a state where they are in contact with each other, to subject the obtained glass for crystallization laminate to a heat treatment including heating at a crystal growth temperature, and to increase the viscosity of the glass for crystallization to η when the crystal growth temperature is reached. １ When heating at the crystal growth temperature is finished, the viscosity is η ２ When this is done, η ２ / η １ The value is 1.0 x 10 ２ That is all, and η ２ is 1.0 x 10 ９ It was confirmed that when the viscosity is Pa·s or more, cracks are less likely to occur in the crystallized glass obtained by peeling.

[0098] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2024-114101 filed on July 17, 2024 are incorporated herein by reference as part of the disclosure of the present invention.

[0099] 10a, 10b, 10c Glass for crystallization 20 Glass for crystallization laminate 22 First setter plate 24 Second setter plate 26 Support 30 Laminate

Claims

1. A method for producing crystallized glass by stacking two or more pieces of glass for crystallization in contact with each other and then heat-treating the resulting glass for crystallization laminate, including heating at a crystal growth temperature, wherein the viscosity of the glass for crystallization when it reaches the crystal growth temperature is η １ and the viscosity at the time of finishing heating at the crystal growth temperature is η ２ When this is done, η ２ / η １ The value is 1.0 x 10 ２ The above, and the η ２ is 1.0 x 10 ９ A method for producing crystallized glass, wherein the viscosity of the crystallized glass is η Pa s or more. １ and the η ２ The unit is Pa·s.

2. The aforementioned η １ But 1.0 x 10 ９ The method for producing crystallized glass according to claim 1, wherein the viscosity is less than Pa·s.

3. The aforementioned η １ But 1.0 x 10 ７ ~5.0 x 10 ８ The method for producing crystallized glass according to claim 1 or 2, wherein the viscosity is Pa·s.

4. The aforementioned η ２ But 1.0 x 10 １０ ~3.0 x 10 １１ The method for producing crystallized glass according to claim 1 or 2, wherein the viscosity is Pa·s.

5. The method for producing crystallized glass according to claim 1 or 2, wherein the crystal growth temperature is 700 to 1100°C.

6. The composition of the glass for crystallization is, in mole percent based on oxides, SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, Li ２ 3. The method for producing crystallized glass according to claim 1, wherein the glass contains 5 to 30% of O.

7. The composition of the glass for crystallization is, in mole percent based on oxides, SiO ２ 60 to 75% Al ２ O ３ 2 to 20%, P ２ O ５ 0 to 5%, Li ２ 5-28% O, Na ２ O 0-4%, K ２ O 0-1%, MgO 0-10%, CaO 0-5%, ZrO ２ 3. The method for producing crystallized glass according to claim 1, wherein the glass contains 0 to 5% of 8. A method for producing crystallized glass, wherein the crystallized glass obtained by the method for producing crystallized glass according to claim 1 or 2 contains one or more crystals selected from the group consisting of lithium silicate crystals and lithium aluminosilicate crystals.

9. A method for producing crystallized glass, wherein the crystallized glass obtained by the method for producing crystallized glass according to claim 1 or 2 contains one or more crystals selected from the group consisting of lithium disilicate crystals, β-spodumene crystals, and petalite crystals.

10. The method for producing crystallized glass according to claim 1 or 2, wherein the thickness of the glass to be crystallized is 1.5 mm or less.

11. A method for producing crystallized glass according to claim 1 or 2, wherein the number of said glass sheets for crystallization in said glass sheet for crystallization laminate is 5 or more, and the total mass of said glass sheet for crystallization laminate is 30 kg or less.

12. The method for producing crystallized glass according to claim 1 or 2, wherein the heat-treated glass for crystallization is peeled off from the heat-treated glass for crystallization laminate to obtain crystallized glass.

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