Crystallized glass, chemically strengthened crystallized glass, and testing method of crystallized glass

Abstract

To provide a crystallized glass and a chemically strengthened crystallized glass having excellent weather resistance.SOLUTION: Provided are a crystallized glass in which a matrix composition contains SiO2 by 60 to 75%, Al2O3 by 3 to 20% and Li2O by 5 to 25% expressed by mol% on the oxide basis, an average coefficient of linear expansion at 250 to 350°C is 90×10-7[ / K] or less, and a mass variation per surface area when immersed in hot water of 80°C for 120 minutes is 1500 μg / cm2 or less compared with before immersion, and a chemically strengthened crystallized glass in which a matrix composition contains SiO2 by 60 to 75%, Al2O3 by 3 to 20% and Li2O by 5 to 25% expressed by mol% on the oxide basis, an average coefficient of linear expansion at 250 to 350°C is 90×10-7[ / K] or less, and a mass variation when immersed in hot water of 80°C for 120 minutes is 8000 μg / cm2 or less compared with before immersion.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to glass-ceramics, chemically strengthened glass-ceramics, and a test method for glass-ceramics, and more particularly to chemically strengthenable glass-ceramics, chemically strengthened glass-ceramics, and a test method for glass-ceramics. [Background technology]

[0002] Chemically strengthened glass is used for the cover glass of mobile terminals, etc. Chemically strengthened glass is produced by bringing glass into contact with a molten salt containing alkali metal ions, for example, to cause ion exchange between the alkali metal ions in the glass and those in the molten salt, thereby forming a compressive stress layer on the glass surface.

[0003] In recent years, glass ceramics have been used as a high-strength material as a base material for such chemically strengthened glass. Glass ceramics is glass in which crystals are precipitated, and is harder and more scratch-resistant than amorphous glass, which does not contain crystals. Furthermore, chemically strengthenable glass ceramics can be made stronger while preventing shattering, compared to amorphous glass. Patent Documents 1 and 2 describe examples of chemically strengthening glass ceramics by ion exchange treatment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 022035 [Patent Document 2] US Patent Application Publication No. 2020 / 0017398 Summary of the Invention [Problem to be solved by the invention]

[0005] The structure of crystallized glass varies depending on its composition and manufacturing method, such as the type of crystals precipitated within the structure, and the drop strength and weather resistance characteristics vary depending on the structure.Crystalized glass with poor weather resistance is prone to surface deterioration due to environmental loads, which leads to the problem of easily reducing surface strength.

[0006] Therefore, an object of the present invention is to provide glass-ceramics and chemically strengthened glass-ceramics that are excellent in weather resistance. [Means for solving the problem]

[0007] As a result of studying the above problems, the inventors have found that crystallized glass having a composition and a mass change per surface area in a boiling water immersion test within a specific range has excellent weather resistance, and have completed the present invention.

[0008] That is, the present disclosure is as follows. 1. The base composition is expressed as mole percent based on oxides. Contains 60-75% SiO2, 3-20% Al2O3, and 5-25% Li2O, Average linear expansion coefficient at 250-350°C is 90 x 10 -7 [ / K] or less, The mass change per surface area after immersion in 80°C hot water for 120 minutes was 1500 μg / cm compared to before immersion. 2 The following is glass-ceramic: 2. Crystal species: Li2Si2O5, LiAlSi2O6, LiAlSi4O 10 2. The crystallized glass according to 1 above, containing at least one selected from the group consisting of Li3PO4 and β-quartz solid solution. 3. The crystallized glass according to 1 above, having a Young's modulus of 70 GPa or more. 4. The crystallized glass according to 1 above, which has a mass change rate of 1000 ppm or less when immersed in hot water at 80°C for 120 minutes. 5. The base composition is expressed as mole percent based on oxides. SiO2 60-75%, Al2O3 3-20%, P2O5 is more than 0% and 4.0% or less, Li2O 5-25%, Na2O 0-2.0%, K2O 0-1%, MgO 0-5% CaO 0-2%, ZrO2: over 0% and up to 5% 2. The crystallized glass according to 1 above, wherein X calculated by the following formula is 0.40 or less. X=a×d a = [LiO] / R d = [Li2O] / [SiO2] R = [Li2O] + [Na2O] + [K2O] The value in [ ] indicates the content of the component in brackets in the base composition, expressed as mole % on an oxide basis. 6. The base composition is expressed as mole percent based on oxides. Contains 60-75% SiO2, 3-20% Al2O3, and 5-25% Li2O, Average linear expansion coefficient at 250-350°C is 90 x 10 -7 [ / K] or less, The mass change after immersion in 80°C hot water for 120 minutes was 8000 μg / cm compared to before immersion. 2 Chemically strengthened glass-ceramics, which are as follows: 7. The plate thickness is t (mm) and the compressive stress layer depth DOC is 0.14t (μm) or more. Surface compressive stress value CS0 is 400 MPa or more, Compressive stress value CS at a depth of 50 μm from the surface 50 is 150t (MPa) or more, and The tensile stress value CT is -350t+400 (MPa) or less. 7. The chemically strengthened glass-ceramics according to 6 above. 8. The chemically strengthened glass-ceramics according to 6 above, having a Young's modulus of 70 GPa or more. 9. The base composition is expressed as mole percent based on oxides. SiO2 60-75%, Al2O3 3-20%, P2O5 is more than 0% and 4.0% or less. Li2O 5-25%, Na2O 0-2.0%, K2O 0-1%, MgO 0-5% CaO 0-2%, ZrO2: 0% or more and 5% or less 7. The chemically strengthened glass-ceramics according to 6 above, wherein X calculated by the following formula is 0.40 or less. X=a×d a = [LiO] / R d = [Li2O] / [SiO2] R = [Li2O] + [Na2O] + [K2O] The value in [ ] indicates the content of the component in brackets in the base composition, expressed as mole % on an oxide basis. 10. Immerse the crystallized glass in hot water at 80°C for 120 minutes and measure the mass change per surface area compared to before immersion; and The mass change per surface area is 1500 μg / cm 2 A method for testing crystallized glass, comprising determining that the product is acceptable if the following conditions are met: 11. Immerse the chemically strengthened glass-ceramics in hot water at 80°C for 120 minutes and measure the mass change per surface area compared to before immersion; and The mass change per surface area is 8000 μg / cm 2 A test method for chemically strengthened crystallized glass, comprising determining that the product is acceptable if the following conditions are met: [Effects of the Invention]

[0009] The crystallized glass and chemically strengthened crystallized glass of the present disclosure have compositions and mass changes per surface area in a boiling water immersion test within specific ranges, and have excellent weather resistance. This provides the advantages of being less susceptible to deterioration of the surface condition due to environmental loads and less reduction in surface strength.

[0010] According to the test method for crystallized glass of the present disclosure, it is possible to efficiently select crystallized glass that has excellent weather resistance and is resistant to deterioration in surface strength due to environmental load. According to the test method for chemically strengthened crystallized glass of the present disclosure, it is possible to efficiently select crystallized glass that has excellent weather resistance and is resistant to deterioration in surface strength due to environmental load. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows the mass change per surface area when a glass material is immersed in hot water at 80° C. (immersion time: 30 minutes or 120 minutes). [Figure 2] Figure 2 shows the results of measuring the surface strength by a BoR strength test after immersing a glass material in hot water at 80°C for 120 minutes. [Figure 3] FIG. 3 shows the correlation between the average coefficient of linear expansion at 250 to 350° C. and the mass change rate in a hot water immersion test. [Figure 4] FIG. 4 is a schematic diagram for explaining the ball-on-ring test method. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to these embodiments. In this specification, unless otherwise specified, the symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0013] "Crystalline glass" is obtained by heat-treating "amorphous glass" to precipitate crystals, and contains crystals. In this specification, "amorphous glass" refers to glass in which no diffraction peaks indicating crystals are observed by the powder X-ray diffraction method described below. In this specification, "amorphous glass" and "crystallized glass" are sometimes collectively referred to as "glass." In addition, amorphous glass that becomes crystallized glass by heat treatment is sometimes referred to as "mother glass of crystallized glass."

[0014] In this specification, powder X-ray diffraction measurement is performed using, for example, CuKα radiation in the 2θ range of 10° to 80°, and if a diffraction peak appears, the precipitated crystals are identified by the Hanawalt method. Furthermore, among the crystals identified by this method, the crystal identified from the peak group containing the peak with the highest integrated intensity is considered to be the main crystal. For example, a Rigaku SmartLab can be used as a measuring device.

[0015] In this specification, the term "residual glass" refers to the amorphous portion of the crystallized glass that has not crystallized.

[0016] In this specification, "chemically strengthened glass" refers to glass after chemical strengthening treatment, and "glass for chemical strengthening" refers to glass before chemical strengthening treatment. In this embodiment, "chemically strengthened crystallized glass" refers to crystallized glass after chemical strengthening treatment.

[0017] In this specification, unless otherwise specified, glass compositions are expressed in mole percent on an oxide basis, and mole percent is simply represented as "%."

[0018] In addition, in this specification, "substantially free" means that the content is below the impurity level contained in raw materials, etc., that is, it is not intentionally added. Specifically, for example, it is less than 0.1%.

[0019] 1. Glass-ceramics The crystallized glass of this embodiment (hereinafter also referred to as the present crystallized glass) has a matrix composition containing, in mole percent on an oxide basis, 60 to 75% SiO, 3 to 20% AlO, and 5 to 25% LiO, and has an average linear expansion coefficient of 90 × 10 at 250 to 350 °C. -7 [ / K] or less, and the mass change after immersion in hot water at 80°C for 120 minutes is 1500μg / cm compared to before immersion. 2 The present invention is characterized by the following:

[0020] (Mass change per surface area in hot water immersion test, mass change rate in hot water immersion test) In this specification, the "mass change per surface area in a hot water immersion test" refers to the value obtained by dividing the mass change compared to before immersion when glass is immersed in hot water (boiling water) at 80°C for 120 minutes by the surface area.

[0021] In this specification, the "mass change rate in a hot water immersion test" refers to the mass change rate of glass when immersed in hot water (boiling water) at 80°C for 120 minutes compared to the mass before immersion.

[0022] The inventors have found that when glass is immersed in boiling water, the amount of mass change per surface area compared to before immersion and the surface strength after immersion in boiling water have a correlation as shown in Figure 1. As shown in Figure 1, the amount of mass change per surface area when glass is immersed in boiling water varies depending on the composition and structure of the glass material (crystallized glass or amorphous glass, and the crystal species contained in crystallized glass), and crystallized glass has a larger amount of mass change than amorphous glass.

[0023] Furthermore, the inventors have found that there is a correlation between the mass change per surface area when glass is immersed in 80°C boiling water for 120 minutes compared to before immersion and the surface strength after immersion in 80°C boiling water for 120 minutes, as shown in Figure 2. Therefore, it is believed that by using the mass change per surface area when glass is immersed in 80°C boiling water for 120 minutes compared to before immersion as an index, it is possible to improve the weather resistance of glass and prevent a decrease in surface strength due to environmental loads.

[0024] When this glass-ceramic was immersed in hot water at 80°C for 120 minutes, the mass change compared to before immersion (hereinafter referred to as the mass change per surface area in the hot water immersion test) was 1500 μg / cm 2 The mass change per surface area in the hot water immersion test is 1500 μg / cm 2 By satisfying the condition below, weather resistance can be improved and a decrease in surface strength due to environmental load can be suppressed.

[0025] The mass change per surface area of ​​the present glass-ceramics in a boiling water immersion test is preferably 1500 μg / cm 2 or less, more preferably 800 μg / cm 2 Below 500 μg / cm, particularly preferably 2 Below 100 μg / cm, most preferably 2The lower limit of the mass change per surface area in the hot water immersion test is not particularly limited, and is 0 μg / cm 2 may be.

[0026] In order to improve weather resistance and prevent the surface strength from decreasing due to environmental load, the mass change rate of the present crystallized glass in a boiling water immersion test is preferably 1000 ppm or less, more preferably 500 ppm or less, even more preferably 300 ppm or less, particularly preferably 100 ppm or less, and most preferably 50 ppm or less.The lower limit of the mass change rate in a boiling water immersion test is not particularly limited, and may be 0 ppm.

[0027] The mass change rate in the hot water immersion test can be adjusted by the linear expansion coefficient, the matrix composition of the glass, the crystallization conditions, the crystal species, the degree of crystallization, and the like.

[0028] (coefficient of linear expansion) This glass-ceramic has an average linear expansion coefficient of 90×10 at 250-350℃. -7 [ / K] or less. Figure 3 shows the correlation between the average coefficient of linear expansion at 250 to 350°C (referred to as "average coefficient of linear expansion" in Figure 3) and the mass change rate in the hot water immersion test. In Figure 3, the horizontal axis represents the mass change rate (ppm) in the hot water immersion test, and the vertical axis represents the average coefficient of linear expansion at 250 to 350°C (10 -7 As shown in Figure 3, there is a correlation between the average linear expansion coefficient at 250 to 350°C and the mass change rate in the hot water immersion test, and the average linear expansion coefficient at 250 to 350°C is 90 × 10 -7 It can be seen that when the average linear expansion coefficient exceeds [ / K], the mass change rate in the hot water immersion test increases. If the average linear expansion coefficient at 250 to 350°C is large, the glass will contain crystalline species with weak network connections, which will be prone to water penetration and crumble, causing mass loss. For this reason, it is thought that the mass change rate in the hot water immersion test increases as the average linear expansion coefficient at 250 to 350°C increases.

[0029] This glass-ceramic has an average linear expansion coefficient of 90×10 at 250-350℃. -7[ / K] or less, the mass change rate in a hot water immersion test is reduced, the weather resistance of the glass is improved, and a decrease in surface strength due to environmental loads can be suppressed. -7 [ / K] or less, more preferably 50 × 10 -7 [ / K] or less, more preferably 30 × 10 -7 [ / K] or less, particularly preferably 10 × 10 -7 [ / K] or less. There is no particular lower limit to the average linear expansion coefficient at 250 to 350° C. The average linear expansion coefficient at 250 to 350° C. can be adjusted by the matrix composition of the glass, the crystallization conditions, the crystal species, the degree of crystallization, etc.

[0030] (crystal seeds) This glass-ceramic contains Li2Si2O5, LiAlSi2O6, and LiAlSi4O as crystal species. 10 Preferably, the material contains at least one selected from Li2Si2O5, LiAlSi2O6, and β-quartz solid solution, and more preferably contains at least one selected from Li2Si2O5, LiAlSi2O6, and β-quartz solid solution. These solid solution crystals may be contained. These crystal species have a small linear expansion coefficient, which can reduce the mass change per surface area in a hot water immersion test and further improve weather resistance.

[0031] In the present crystallized glass, the molar ratio of Si to Li in the main crystals (Si / Li) is preferably 0.9 to 5.0, from the viewpoint of further reducing the mass change per surface area in a hot water immersion test. From the viewpoint of further reducing the mass change per surface area in a hot water immersion test, the ratio (Si / Li) in the main crystals is preferably 1.0 or more, more preferably 1.2 or more, even more preferably 1.4 or more, and particularly preferably 1.6 or more. From the viewpoint of improving the chemical resistance of the glass, the ratio (Si / Li) in the main crystals is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.5 or less.

[0032] In the present crystallized glass, the molar ratio of Al to Li in the main crystal (Al / Li) is preferably greater than 0, from the viewpoint of further reducing the mass change per surface area in a hot water immersion test. From the viewpoint of further reducing the mass change per surface area in a hot water immersion test, the ratio (Al / Li) in the main crystal is preferably greater than 0, more preferably 0.5 or more, even more preferably 0.75 or more, and particularly preferably 1 or more. There is no particular upper limit to the numerical value of the ratio (Al / Li).

[0033] The ratio of Si to Li (Si / Li) and the ratio of Al to Li (Al / Li) in the primary crystal are determined from the primary crystal's chemical formula. For example, if the primary crystal is LiAlSi2O6, (Si / Li) is 2.0 and (Al / Li) is 1.0. If the primary crystal is Li2Si2O5, (Si / Li) is 1.0 and (Al / Li) is 0.

[0034] (crystallinity) The crystallinity of the present crystallized glass is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. By making the crystallinity 50% or more, the mass change per surface area in a hot water immersion test can be reduced, thereby improving weather resistance and increasing strength. From the viewpoint of ensuring transparency, the crystallinity is preferably 97% or less, more preferably 95% or less, and even more preferably 90% or less. The crystallinity can be calculated by measuring powder X-ray diffraction and using the Rietveld method.

[0035] The average particle size of the precipitated crystals in the present crystallized glass is preferably 5 nm or more, particularly preferably 10 nm or more. To improve transparency, it is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. The average particle size of the precipitated crystals can be determined from a transmission electron microscope (TEM) image.

[0036] (Young's modulus) The Young's modulus of this crystallized glass is preferably 70GPa or more, more preferably 80GPa or more, even more preferably 85GPa or more, and particularly preferably 90GPa or more.By making the Young's modulus 70GPa or more, the rigidity of glass can be increased, and strength can be improved.From the viewpoint of easy polishing, the Young's modulus is preferably 120GPa or less, more preferably 110GPa or less, and even more preferably 105GPa or less.

[0037] (Fracture toughness value) The fracture toughness value of this glass-ceramic (K IC ) is preferably 0.70 MPa m 1 / 2 More preferably, 0.80 MPa m 1 / 2 More preferably, 0.85 MPa m 1 / 2 More than 0.95 MPa m 1 / 2 or more, most preferably 1.05 MPa m 1 / 2 The fracture toughness value is 0.70 MPa m 1 / 2 If the fracture toughness is 1.5 MPa m or more, the glass-ceramics have high impact resistance and are less likely to break severely even when a large compressive stress is applied by chemical strengthening. 1 / 2 The "fracture toughness value" in this specification is a value obtained by the IF method defined in JIS R1607:2015.

[0038] (Surface strength) In this specification, the term "surface strength" refers to a value measured by a test under the following conditions (Ball on Ring strength test, hereinafter also abbreviated as BoR strength test). BoR strength test conditions: A glass plate with a thickness of t (mm) is placed on a stainless steel ring with a diameter of 30 mm and a rounded contact area with a radius of curvature of 2.5 mm, and a steel sphere with a diameter of 10 mm is placed in contact with the glass plate. The sphere is loaded at the center of the ring under static loading conditions, and the breaking load (unit: N) at which the glass breaks is taken as the BoR strength. The average of 10 measurements of the BoR strength is taken as the surface strength. However, if the starting point of the glass breaks 2 mm or more away from the loading point of the sphere, the data is excluded from calculating the average value.

[0039] A schematic diagram for explaining the ball-on-ring test is shown in Figure 4. In the Ball-on-Ring (BoR) test, a glass plate 1 is placed horizontally and pressure is applied to the glass plate 1 using a pressure jig 2 made of SUS304 (hardened steel, diameter 10 mm, mirror finish) to measure the strength of the glass plate 1.

[0040] In Fig. 4, a sample glass plate 1 is placed horizontally on a receiving jig 3 made of SUS304 (diameter 30 mm, curvature R2.5 mm at the contact part, contact part made of hardened steel, mirror-finished). A pressing jig 2 for applying pressure to the glass plate 1 is placed above the glass plate 1. In this embodiment, pressure is applied to the central region of the glass plate 1 from above.

[0041] The test conditions are as follows: Descending speed of pressure jig 2: 1.0 (mm / min) The breaking load (unit: N) when the glass plate breaks is taken as the BoR strength, and the average value of 10 measurements of the BoR strength is taken as the surface strength (N). However, if the fracture origin of the glass plate is 2 mm or more away from the load point of the sphere, this data is excluded from the calculation of the average value.

[0042] The present crystallized glass preferably has a surface strength of 340 N or more after immersion in 80°C hot water for 120 minutes, more preferably 360 N or more, even more preferably 380 N or more, and particularly preferably 400 N or more. There is no particular upper limit to the surface strength after immersion in 80°C hot water for 120 minutes.

[0043] (Thickness and shape) When the present crystallized glass is in a plate form, the thickness (t) is preferably 0.30 to 1.00 mm. The thickness is more preferably 0.90 mm or less, even more preferably 0.80 mm or less, particularly preferably 0.70 mm or less, and most preferably 0.65 mm or less. From the viewpoint of further increasing the strength, the thickness is more preferably 0.35 mm or more, even more preferably 0.40 mm or more, particularly preferably 0.45 mm or more, and most preferably 0.50 mm or more.

[0044] The shape of the present crystallized glass may be other than a plate shape depending on the product or use to which it is applied. The present crystallized glass may also have a border shape with different peripheral thicknesses. The shape of the present crystallized glass is not limited to this, and for example, the two main surfaces may not be parallel to each other, and one or both of the two main surfaces may be entirely or partially curved. More specifically, the present crystallized glass may be, for example, a flat glass plate without warping, or a curved glass plate with a curved surface.

[0045] (Mother composition of glass-ceramics) The matrix composition of this glass-ceramics is expressed in mole percent on an oxide basis and contains 60 to 75% SiO2, 3 to 20% Al2O3, and 5 to 25% Li2O.

[0046] This glass-ceramic has a matrix composition expressed as mole percent based on oxides. SiO2 60-75%, Al2O3 3-20%, P2O5 is more than 0% and 4.0% or less, Li2O 5-25%, Na2O 0-2.0%, K2O 0-1%, MgO 0-5% CaO 0-2%, ZrO2: over 0% and up to 5% It is preferable that X calculated by the following formula is 0.40 or less. X=a×d a = [LiO] / R d = [Li2O] / [SiO2] R = [Li2O] + [Na2O] + [K2O] The value in [ ] indicates the content of the component in brackets in the base composition, expressed as mole % on an oxide basis. The composition of the present glass-ceramics will be explained below.

[0047] SiO2 is a component that forms the network structure of glass. The SiO2 content is 60% or more, preferably 62% or more, more preferably 64% or more, even more preferably 66% or more, particularly preferably 68% or more, and most preferably 70% or more. On the other hand, to improve meltability, the SiO2 content is 75% or less, preferably 74% or less, more preferably 73% or less, even more preferably 72% or less, and particularly preferably 70% or less.

[0048] Al2O3 is an essential component that increases the surface compressive stress due to chemical strengthening. The Al2O3 content is 3% or more, preferably 4% or more, more preferably 5% or more, still more preferably 7% or more, 9% or more, 11% or more, 13% or more, particularly preferably 14% or more, and most preferably 15% or more. On the other hand, the Al2O3 content is 20% or less, preferably 19% or less, more preferably 18% or less, even more preferably 17% or less, and most preferably 16% or less, so that the devitrification temperature of the glass does not become too high.

[0049] P2O5 is a component that can be a constituent of crystals, and is preferably contained from the viewpoint of promoting crystallization. The P2O5 content is preferably more than 0%, more preferably 0.5% or more, even more preferably 1.0% or more, particularly preferably 1.5% or more, and most preferably 2.0% or more. On the other hand, if the P2O5 content is too high, phase separation may occur easily during melting and weather resistance may decrease, so the P2O5 content is preferably 4.0% or less, more preferably 3.5% or less, even more preferably 3.0% or less, and particularly preferably 2.5% or less.

[0050] Li2O is a component that forms surface compressive stress through ion exchange and is essential because it is a constituent of the main crystal. The Li2O content is 5% or more, preferably 7% or more, more preferably 10% or more, more preferably 12% or more, even more preferably 15% or more, particularly preferably 17% or more, and most preferably 19% or more. On the other hand, to stabilize the glass, the Li2O content is 25% or less, preferably 23% or less, more preferably 21% or less, and most preferably 20% or less.

[0051] Na2O is a component that improves the meltability of glass. Na2O is not essential, but when it is contained, it is preferably 0.5% or more, more preferably 1% or more, and particularly preferably 2% or more. If the Na2O content is too high, the chemical strengthening properties may be reduced, so the Na2O content is preferably 2.0% or less, more preferably 1.8% or less, even more preferably 1.5% or less, and particularly preferably 1.2% or less.

[0052] Like Na2O, K2O is a component that lowers the melting temperature of glass and may be contained. When K2O is contained, the content is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.3% or more, and particularly preferably 0.5% or more. If the amount of K2O is too much, the chemical strengthening properties may be reduced, so the content is preferably 1% or less, more preferably 0.8% or less, even more preferably 0.7% or less, and most preferably 0.6% or less.

[0053] In the present crystallized glass, it is preferable that X, calculated by the following formula, is 0.40 or less. By having X be 0.40 or less, the SiO2 network connections of the glass are strengthened and water penetration is suppressed, thereby reducing the mass change per surface area in a boiling water immersion test and further improving weather resistance. X=a×d a = [LiO] / R d = [Li2O] / [SiO2] R = [Li2O] + [Na2O] + [K2O] The value in [ ] indicates the content of the component in brackets in the base composition, expressed as mole % on an oxide basis.

[0054] X calculated by the above formula is more preferably 0.35 or less, even more preferably 0.30 or less, particularly preferably 0.20 or less, and most preferably 0.10 or less. There is no particular lower limit for X, but it is, for example, 0.001 or more.

[0055] From the viewpoint of reducing the mass change per surface area in a hot water immersion test, the value of a([LiO] / R) is preferably 1.00 or less, more preferably 0.9 or less, and even more preferably 0.80 or less. From the viewpoint of improving ion exchange properties, the value of a is preferably 0.40 or more, more preferably 0.50 or more, and even more preferably 0.60 or more.

[0056] From the viewpoint of reducing the mass change per surface area in a hot water immersion test, the value of d([Li2O] / [SiO2]) is preferably 0.50 or less, more preferably 0.40 or less, and even more preferably 0.30 or less. Moreover, from the viewpoint of improving chemical strengthening properties, the value of d is preferably 0.05 or more, more preferably 0.10 or more, and even more preferably 0.20 or more.

[0057] From the viewpoint of reducing the mass change per surface area in a hot water immersion test, the R([LiO]+[NaO]+[KO]) is preferably 7.0% or more, more preferably 10.0% or more, and even more preferably 15.0% or more. From the viewpoint of improving chemical resistance, the value of R is preferably 40.0% or less, more preferably 30.0% or less, and even more preferably 20.0% or less.

[0058] From the viewpoint of reducing the mass change per surface area in a boiling water immersion test, the present crystallized glass preferably has a Q value of 0.20 or more, more preferably 1.00 or more, even more preferably 1.50 or more, and most preferably 2.00 or more, represented by the formula [Al2O3] / R. Furthermore, from the viewpoint of improving meltability during glass production, the Q value is preferably 5.00 or less, more preferably 4.00 or less, and even more preferably 3.00 or less.

[0059] MgO is a component that stabilizes glass and also enhances mechanical strength and weather resistance, so it is preferably contained. When MgO is contained, the MgO content is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 2.0% or more, and particularly preferably 2.5% or more. On the other hand, if too much MgO is added, the viscosity of the glass decreases and devitrification or phase separation becomes more likely to occur, so the MgO content is preferably 5% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and particularly preferably 3.5% or less.

[0060] CaO is a component that improves the meltability of glass and enhances weather resistance, and is preferably contained. When CaO is contained, the CaO content is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.4% or more, particularly preferably 0.6% or more, and most preferably 0.8% or more. On the other hand, if too much CaO is added, the ion exchange rate may decrease, so the CaO content is preferably 2.0% or less, more preferably 1.8% or less, even more preferably 1.6% or less, and particularly preferably 1.4% or less.

[0061] ZrO2 is a component that increases mechanical strength and significantly improves CS when ion-exchanged, so it is preferably contained. The ZrO2 content is preferably more than 0%, more preferably 0.5% or more, even more preferably 1.0% or more, even more preferably 1.5% or more, particularly preferably 2.0% or more, and most preferably 2.5% or more. On the other hand, in order to suppress devitrification during melting and deterioration of formability, the ZrO2 content is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, particularly preferably 3.5% or less, and most preferably 3.0% or less.

[0062] Y2O3 is a component that, when ion-exchanged, has the effect of preventing fragments from scattering when chemically strengthened glass breaks, and may be contained. The Y2O3 content is preferably 1.0% or more, more preferably 1.5% or more, even more preferably 2.0% or more, particularly preferably 2.5% or more, and extremely preferably 3.0% or more. On the other hand, in order to suppress devitrification during melting, the Y2O3 content is preferably 5.0% or less, more preferably 4.0% or less.

[0063] B2O3 is a component that improves the chipping resistance and meltability of glass and may be contained. When B2O3 is contained, the content is preferably 0.5% or more, more preferably 1% or more, and even more preferably 2% or more in order to improve meltability. On the other hand, if the B2O3 content is too high, striae may occur during melting or phase separation may occur, which may lead to a deterioration in the quality of the glass for chemical strengthening. Therefore, the B2O3 content is preferably 10% or less, more preferably 8% or less, even more preferably 6% or less, and particularly preferably 4% or less.

[0064] SnO2 has the effect of promoting the formation of crystal nuclei and may be contained. When SnO2 is contained, the SnO2 content is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and particularly preferably 2.0% or more. On the other hand, in order to suppress devitrification during melting, the SnO2 content is preferably 4.0% or less, more preferably 3.5% or less, even more preferably 3.0% or less, and particularly preferably 2.5% or less.

[0065] TiO2 is a component that can promote crystallization and may be contained. When TiO2 is contained, the content of TiO2 is preferably 0.2% or more, more preferably 0.5% or more. On the other hand, in order to suppress devitrification during melting, the content of TiO2 is preferably 4% or less, more preferably 2% or less, and even more preferably 1% or less.

[0066] BaO, SrO, and ZnO may be added to improve the refractive index of the residual glass, bringing it closer to the precipitated crystalline phase and thereby improving the light transmittance of the crystallized glass. In this case, the total content of BaO, SrO, and ZnO (hereinafter referred to as BaO + SrO + ZnO) is preferably 0.3% or more, more preferably 0.5% or more, even more preferably 0.7% or more, and particularly preferably 1% or more. On the other hand, these components may reduce the ion exchange rate. To improve chemical strengthening properties, BaO + SrO + ZnO is preferably 2.5% or less, more preferably 2% or less, even more preferably 1.7% or less, and particularly preferably 1.5% or less.

[0067] La2O3, Nb2O5, and Ta2O5 are all components that prevent chemically strengthened glass from scattering fragments when broken, and may be included to increase the refractive index. When these are included, the total content of La2O3, Nb2O5, and Ta2O5 (hereinafter, La2O3 + Nb2O5 + Ta2O5) is preferably 0.5% or more, more preferably 1% or more, even more preferably 1.5% or more, and particularly preferably 2% or more. Furthermore, to prevent the glass from devitrifying during melting, La2O3 + Nb2O5 + Ta2O5 is preferably 4% or less, more preferably 3% or less, even more preferably 2% or less, and particularly preferably 1% or less.

[0068] CeO2 is a component that may suppress coloration by oxidizing the glass, and may be contained. When CeO2 is contained, the CeO2 content is preferably 0.03% or more, more preferably 0.05% or more, and even more preferably 0.07% or more. To increase transparency, the CeO2 content is preferably 1.5% or less, and more preferably 1.0% or less.

[0069] When the present crystallized glass is used in a colored state, coloring components may be added within a range that does not impede the achievement of the desired chemical strengthening properties, such as Co3O4, MnO2, Fe2O3, NiO, CuO, Cr2O3, V2O5, Bi2O3, SeO2, Er2O3, and Nd2O3.

[0070] The total content of coloring components is preferably in the range of 1% or less. If a higher visible light transmittance of the glass is desired, it is preferable that these components are substantially not contained.

[0071] Furthermore, SO3, chlorides, and fluorides may be appropriately contained as fining agents during melting of the glass. It is preferable that As2O3 is not contained. When As2O3 is contained, the content is preferably 0.3% or less, more preferably 0.1% or less, and most preferably, no As2O3 is contained.

[0072] (Method of manufacturing glass-ceramics) The method for producing crystallized glass includes the following steps (A1) and (A2): (A1) A step of preparing amorphous glass (A2) A step of crystallizing the amorphous glass obtained in (A1) to obtain crystallized glass. Each step will be described below.

[0073] [(A1) Step of preparing amorphous glass] Amorphous glass can be produced, for example, by the following method: The production method described below is an example of producing plate-shaped crystallized glass.

[0074] Glass raw materials are blended to obtain glass of a desired composition, and then heated and melted in a glass melting furnace. The molten glass is then homogenized by bubbling, stirring, adding a fining agent, etc., and formed into a glass plate of a predetermined thickness by a known forming method, and slowly cooled. Alternatively, the molten glass may be formed into a block, slowly cooled, and then cut into a plate.

[0075] [(A2) A step of crystallizing the amorphous glass obtained in (A1) to obtain crystallized glass] In step (A2), the amorphous glass obtained in step (A1) is heat-treated to precipitate crystals inside the glass, thereby obtaining crystallized glass.

[0076] The heat treatment preferably includes a two-stage heat treatment: 1) raising the temperature from room temperature to a first treatment temperature and holding it for a certain period of time, and then 2) holding it for a certain period of time at a second treatment temperature that is higher than the first treatment temperature.

[0077] 1) Heat treatment at a first treatment temperature The heat treatment at the first treatment temperature is preferably held at 500 to 850°C, more preferably 520 to 800°C, and even more preferably 550 to 750°C for preferably 1 to 6 hours, more preferably 2 to 5 hours, and even more preferably 3 to 4 hours. By carrying out the heat treatment at the first treatment temperature for a long period of time, preferably at a relatively high temperature range of 500 to 850°C, preferably for 1 to 6 hours, the generation of crystal nuclei can be promoted, the degree of crystallization can be increased, and the amount of mass change per surface area in a hot water immersion test can be reduced, thereby further improving weather resistance.

[0078] 2) Heat treatment at the second treatment temperature The heat treatment at the second treatment temperature is preferably held at 600 to 1000°C, more preferably 650 to 950°C, and even more preferably 700 to 900°C for preferably 0.2 to 10 hours, more preferably 2 to 8 hours, and even more preferably 3 to 6 hours. By carrying out the heat treatment at the second treatment temperature for a long period of time, preferably at a relatively high temperature range of 600 to 1000°C, preferably for 0.2 to 10 hours, the generation of crystal nuclei can be promoted, the degree of crystallization can be increased, and the amount of mass change per surface area in a hot water immersion test can be reduced, thereby further improving weather resistance.

[0079] 2. Chemically strengthened glass-ceramics In this specification, "chemically strengthened glass-ceramics" refers to glass in which a compressive stress layer is formed on the surface by performing an ion exchange treatment on the glass-ceramics. The chemically strengthened glass-ceramics of this embodiment (hereinafter also referred to as the present chemically strengthened glass-ceramics) is obtained by chemically strengthening the above-mentioned glass-ceramics of this embodiment.

[0080] This chemically strengthened glass-ceramic has a matrix composition of 60-75% SiO2, 3-20% Al2O3, and 5-25% Li2O, expressed in mole percent based on oxides, and has an average linear expansion coefficient of 90 x 10 at 250-350°C. -7 [ / K] or less, and the mass change per surface area when immersed in hot water at 80°C for 120 minutes is 8000 μg / cm compared to before immersion. 2 The present invention is characterized by the following:

[0081] (Mass change per surface area in hot water immersion test, mass change rate in hot water immersion test) This chemically strengthened glass-ceramic has a mass change of 8000 μg / cm per surface area when immersed in hot water at 80°C for 120 minutes. 2 The mass change per surface area in the hot water immersion test is 8000 μg / cm 2 By satisfying the condition below, weather resistance can be improved and a decrease in surface strength due to environmental load can be suppressed.

[0082] The chemically strengthened glass-ceramics preferably has a mass change per surface area of ​​6000 μg / cm in a hot water immersion test. 2 or less, more preferably 3000 μg / cm 2 Below 1000 μg / cm, particularly preferably 2 Below 600 μg / cm, most preferably 2 The mass change per surface area in the hot water immersion test can be adjusted by the linear expansion coefficient, the matrix composition of the glass, the crystallization conditions, the crystal species, the degree of crystallization, and the like.

[0083] (coefficient of linear expansion) This chemically strengthened glass-ceramic has an average linear expansion coefficient of 90×10 at 250-350℃. -7 The average linear expansion coefficient at 250 to 350°C is 90 × 10 -7 [ / K] or less, the mass change per surface area in a hot water immersion test can be reduced, weather resistance can be improved, and a decrease in surface strength due to environmental load can be suppressed. -7 [ / K] or less, more preferably 50 × 10 -7 [ / K] or less, more preferably 30 × 10 -7 [ / K] or less, particularly preferably 10 × 10 -7 [ / K] or less. There is no particular lower limit to the average linear expansion coefficient at 250 to 350° C. The average linear expansion coefficient at 250 to 350° C. can be adjusted by the matrix composition of the glass, the crystallization conditions, the crystal species, the degree of crystallization, etc.

[0084] (Young's modulus) The Young's modulus of the chemically strengthened glass-ceramics is preferably 70 GPa or more, more preferably 80 GPa or more, even more preferably 85 GPa or more, and particularly preferably 90 GPa or more. A Young's modulus of 70 GPa or more can increase the rigidity of the glass and improve its strength. From the viewpoint of ease of polishing, the Young's modulus is preferably 120 GPa or less, more preferably 110 GPa or less, and even more preferably 105 GPa or less.

[0085] (Surface strength) The chemically strengthened glass-ceramics preferably has a surface strength of 450 N or more after immersion in 80°C hot water for 120 minutes, more preferably 470 N or more, even more preferably 490 N or more, and particularly preferably 520 N or more. There is no particular upper limit to the surface strength after immersion in 80°C hot water for 120 minutes.

[0086] (Thickness and shape) The preferred thickness and shape of the present chemically strengthened glass-ceramics are the same as those of the present glass-ceramics described above.

[0087] (Master composition, crystal species and crystallinity of chemically strengthened glass-ceramics) The matrix composition of the present chemically strengthened glass-ceramics is the same as the matrix composition of the present chemically strengthened glass described above, and the preferred composition range is also the same. When the chemically strengthened glass-ceramics is plate-shaped, the content ratio of alkali metal elements differs between the surface and the center in the thickness direction. On the other hand, except in cases where extreme ion exchange treatment has been performed, the glass composition at the deepest part from the surface of the chemically strengthened glass-ceramics is the same as the matrix composition of the chemically strengthened glass-ceramics. When the chemically strengthened glass-ceramics is plate-shaped, the deepest part from the glass surface is, for example, a depth of 1 / 2 of the plate thickness t.

[0088] The preferred crystal species and crystallinity of the present chemically strengthened glass-ceramics are the same as those of the present glass-ceramics described above.

[0089] (Method of manufacturing chemically strengthened glass-ceramics) The method for producing the chemically strengthened glass-ceramics includes the following steps (B1) to (B3). (B1) A step of preparing amorphous glass (B2) A step of crystallizing the amorphous glass obtained in (B1) to obtain crystallized glass. (B3) A step of chemically strengthening the crystallized glass obtained in (B2) (ion exchange treatment) to obtain chemically strengthened crystallized glass.

[0090] The steps (B1) and (B2) are the same as the steps (A1) and (A2) respectively described in the section (Method for producing crystallized glass). Step (B3) will be described below. (B3) A step of chemically strengthening the crystallized glass obtained in (B2) (ion exchange treatment) to obtain chemically strengthened crystallized glass.

[0091] In this embodiment, the chemical strengthening treatment is carried out by immersing the crystallized glass for preferably 0.1 to 500 hours in a molten salt such as potassium nitrate heated to preferably 360 to 600° C. The heating temperature of the molten salt is preferably 360 to 600° C., more preferably 375 to 500° C. The immersion time of the crystallized glass in the molten salt is preferably 0.1 to 500 hours, more preferably 0.3 to 200 hours.

[0092] Examples of molten salts used in chemical strengthening include nitrates, sulfates, carbonates, and chlorides. Nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate. Sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate. Carbonates include lithium carbonate, sodium carbonate, and potassium carbonate. Chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts may be used alone or in combination.

[0093] In this embodiment, the processing conditions for the chemical strengthening treatment may be selected appropriately taking into consideration the properties and composition of the crystallized glass to be subjected to the chemical strengthening treatment, the type of molten salt, and the chemical strengthening properties, such as the surface compressive stress and the depth of the compressive stress layer, desired for the final chemically strengthened crystallized glass.

[0094] In this embodiment, the chemical strengthening treatment may be carried out only once, or may be carried out a plurality of times under two or more different conditions (multi-stage strengthening).

[0095] (Stress characteristics of chemically strengthened glass-ceramics) In this specification, the term "stress profile" refers to a representation of compressive stress values ​​with depth from the glass surface as a variable. In the stress profile, tensile stress is represented as negative compressive stress.

[0096] The "compressive stress value (CS)" can be measured by cutting a cross section of glass into thin slices and analyzing the sliced ​​samples with a birefringence imaging system. A birefringence imaging system birefringence stress meter is a device that measures the magnitude of retardation caused by stress using a polarizing microscope and a liquid crystal compensator, etc., and one example is the birefringence imaging system Abrio-IM manufactured by CRi.

[0097] To obtain the stress profile of glass nondestructively, for example, a scattered light photoelastic stress meter (hereinafter also abbreviated as SLP) and a glass surface stress measurement (hereinafter also abbreviated as FSM) can be used in combination. For chemically strengthened glass, the stress profile of the glass surface and interior may be obtained by combining information from SLP and FSM.

[0098] For crystallized glass (e.g., glass containing LiAlSi2O6), stress can be measured using FSM after chemical strengthening. Methods using FSM can measure compressive stress resulting from Na-K exchange in the surface layer of the glass, within a few tens of micrometers from the glass surface (e.g., International Publication Nos. 2018 / 056121 and 2017 / 115811). An example of a glass surface stress meter is the FSM-6000 glass surface stress meter manufactured by Orihara Seisakusho Co., Ltd.

[0099] Stress in deep layers can sometimes be measured using scattered light photoelasticity. With this method, light is incident on the surface of the glass, and the polarization of the scattered light is analyzed to measure CS. An example of a stress measuring device that uses scattered light photoelasticity is the SLP-2000 scattered light photoelasticity meter manufactured by Orihara Seisakusho.

[0100] In this specification, the "depth of compressive stress layer (DOC)" is the depth at which the compressive stress value becomes zero. Hereinafter, the surface compressive stress value is referred to as CS0, and the compressive stress value at a depth of 50 μm is referred to as CS 50 The surface compressive stress value CSO and the compressive stress layer depth DOC can be measured using a surface stress meter [for example, a surface stress meter (FSM-6000) manufactured by Orihara Seisakusho].

[0101] In this specification, "tensile stress value (CT)" refers to the tensile stress value at a depth of 1 / 2 of the plate thickness t. t / 2 " is equivalent to

[0102] The chemically strengthened crystallized glass has a plate thickness of t (mm) and a compressive stress layer depth DOC of 0.14t (μm) or more, more preferably 0.16t (μm) or more, even more preferably 0.18t (μm) or more, and particularly preferably 0.2t (μm) or more. A DOC of 0.14t (μm) or more is preferable because it is less likely to break even if scratches occur on the surface. The DOC is preferably 0.25t (μm) or less to shorten the time required for chemical strengthening.

[0103] The chemically strengthened glass-ceramics preferably has a surface compressive stress (CS0) of 400 MPa or more, since it is less likely to break due to deformation such as bending. CS0 is more preferably 450 MPa or more, even more preferably 500 MPa or more, and particularly preferably 600 MPa or more. The greater the CS0, the greater the strength, but if it is too large, severe fracture may occur if it breaks, so CS0 is preferably 1400 MPa or less, more preferably 1300 MPa or less.

[0104] This chemically strengthened glass-ceramic has a thickness of t (mm) and a compressive stress value CS at a depth of 50 μm from the surface. 50 It is preferable that the CS is 150t (MPa) or more. 50 If the CS is 150 t (MPa) or more, it is easy to suppress the chemically strengthened glass-ceramics from cracking when a mobile terminal or the like equipped with the chemically strengthened glass-ceramics as a cover glass is dropped, which is preferable. 50 is more preferably 150t+40 (MPa) or more, even more preferably 150t+60 (MPa) or more, particularly preferably 150t+80 (MPa) or more, and most preferably 150t+100 (MPa) or more. 50 The larger the tensile strength, the higher the strength. However, if the tensile strength is too large, severe fracture may occur if the tensile strength is too high. Therefore, the tensile strength is preferably 150t+200 (MPa) or less.

[0105] The chemically strengthened crystallized glass preferably has a thickness of t (mm) and a tensile stress value CT of -350t+400 (MPa) or less. Having a tensile stress value CT of -350t+400 (MPa) or less provides greater durability against external forces and impacts, making it less likely to break, and even if the glass does break, it is less likely to scatter fragments. CT is more preferably -350t+380 (MPa) or less, even more preferably -350t+360 (MPa) or less, and particularly preferably -350t+320 (MPa) or less. From the viewpoint of strength and durability, CT is preferably -350t+260 (MPa) or more, more preferably -350t+280 (MPa) or more.

[0106] 3.Applications The present glass-ceramics and the present chemically strengthened glass-ceramics are useful as cover glass for electronic devices such as mobile devices such as mobile phones and smartphones. They are also useful as cover glass for non-portable electronic devices such as televisions, personal computers, and touch panels, as elevator walls, and as wall surfaces (full-surface displays) for buildings such as houses and buildings. They are also useful as building materials such as window glass, tabletops, interiors of automobiles and airplanes, and their cover glass, as well as for curved housings.

[0107] 4. Testing methods for glass-ceramics The method for testing crystallized glass of this embodiment is characterized by including the following steps (C1) and (C2). (C1) A step of immersing the crystallized glass in hot water at 80°C for 120 minutes and measuring the mass change per surface area compared to before immersion (C2) The mass change per surface area measured in (C1) compared to before immersion was 1500 μg / cm 2 A process that includes determining that the product is acceptable if:

[0108] (C1) A step of immersing the crystallized glass in hot water at 80°C for 120 minutes and measuring the mass change per surface area. Step (C1) is a step of measuring the mass change per surface area in a hot water immersion test. Specific conditions for the hot water immersion test include, for example, the following. Conditions: A 50mm x 50mm x 0.7mm piece of glass was immersed in 80°C pure water for 120 minutes, and the mass after immersion was subtracted from the mass before immersion, and the mass change was divided by the surface area to determine the value.

[0109] (C2) The mass change per surface area measured in (C1) is 1500 μg / cm 2 A process that includes determining that the product is acceptable if: Step (C2) is a step of evaluating the glass based on the mass change per surface area measured in step (C1). In step (C2), the mass change per surface area is 1500 μg / cm 2It is considered to be a pass if it is less than 1500μg / cm 2 If it is greater than 100%, it is deemed non-compliant.

[0110] 5. Test methods for chemically strengthened glass-ceramics The test method for chemically strengthened glass-ceramics of this embodiment is characterized by including the following steps (D1) and (D2). (D1) A process of immersing chemically strengthened glass-ceramics in hot water at 80°C for 120 minutes and measuring the mass change per surface area compared to before immersion (D2) The mass change per surface area measured in (D1) compared to before immersion was 8000 μg / cm 2 A process that includes determining that the product is acceptable if:

[0111] (D1) A process of immersing chemically strengthened glass-ceramics in hot water at 80°C for 120 minutes and measuring the mass change per surface area. Step (D1) is a step of measuring the mass change per surface area in a hot water immersion test. Specific conditions for the hot water immersion test include, for example, the following. Conditions: A 50mm x 50mm x 0.7mm piece of glass was immersed in 80°C pure water for 120 minutes, and the mass after immersion was subtracted from the mass before immersion, and the mass change was divided by the surface area to determine the value.

[0112] (D2) The mass change per surface area measured in (D1) is 8000 μg / cm 2 A process that includes determining that the product is acceptable if: Step (D2) is a step of evaluating the glass based on the mass change per surface area measured in step (D1). In step (D2), the mass change per surface area is 8000 μg / cm 2 It is considered to pass if it is less than 8000μg / cm 2 If it is greater than 100%, it is deemed non-compliant.

[0113] As described above, the present specification discloses the following configurations. 1. The base composition is expressed as mole percent based on oxides. Contains 60-75% SiO2, 3-20% Al2O3, and 5-25% Li2O, Average linear expansion coefficient at 250-350°C is 90 x 10 -7 [ / K] or less, The mass change per surface area after immersion in 80°C hot water for 120 minutes was 1500 μg / cm compared to before immersion. 2 The following is glass-ceramic: 2. Crystal species: Li2Si2O5, LiAlSi2O6, LiAlSi4O 10 2. The crystallized glass according to 1 above, containing at least one selected from the group consisting of Li3PO4 and β-quartz solid solution. 3. The crystallized glass according to 1 or 2 above, having a Young's modulus of 70 GPa or more. 4. The crystallized glass according to any one of 1 to 3 above, which has a mass change rate of 1000 ppm or less when immersed in hot water at 80° C. for 120 minutes. 5. The base composition is expressed as mole percent based on oxides. SiO2 60-75%, Al2O3 3-20%, P2O5 is more than 0% and 4.0% or less, Li2O 5-25%, Na2O 0-2.0%, K2O 0-1%, MgO 0-5% CaO 0-2%, ZrO2: over 0% and up to 5% 5. The crystallized glass according to any one of 1 to 4 above, wherein X calculated by the following formula is 0.40 or less. X=a×d a = [LiO] / R d = [Li2O] / [SiO2] R = [Li2O] + [Na2O] + [K2O] The value in [ ] indicates the content of the component in brackets in the base composition, expressed as mole % on an oxide basis. 6. The base composition is expressed as mole percent based on oxides. Contains 60-75% SiO2, 3-20% Al2O3, and 5-25% Li2O, Average linear expansion coefficient at 250-350°C is 90 x 10 -7 [ / K] or less, The mass change after immersion in 80°C hot water for 120 minutes was 8000 μg / cm compared to before immersion. 2 Chemically strengthened glass-ceramics, which are as follows: 7. The plate thickness is t (mm) and the compressive stress layer depth DOC is 0.14t (μm) or more. Surface compressive stress value CS0 is 400 MPa or more, Compressive stress value CS at a depth of 50 μm from the surface 50 is 150t (MPa) or more, and The tensile stress value CT is -350t+400 (MPa) or less. 7. The chemically strengthened glass-ceramics according to 6 above. 8. The chemically strengthened glass-ceramics according to 6 or 7 above, which has a Young's modulus of 70 GPa or more. 9. The base composition is expressed as mole percent based on oxides. SiO2 60-75%, Al2O3 3-20%, P2O5 is more than 0% and 4.0% or less. Li2O 5-25%, Na2O 0-2.0%, K2O 0-1%, MgO 0-5% CaO 0-2%, ZrO2: 0% or more and 5% or less 9. The chemically strengthened crystallized glass according to any one of 6 to 8 above, wherein X calculated by the following formula is 0.40 or less. X=a×d a = [LiO] / R d = [Li2O] / [SiO2] R = [Li2O] + [Na2O] + [K2O] The value in [ ] indicates the content of the component in brackets in the base composition, expressed as mole % on an oxide basis. 10. Immerse the crystallized glass in hot water at 80°C for 120 minutes and measure the mass change per surface area compared to before immersion; and The mass change per surface area is 1500 μg / cm 2A method for testing crystallized glass, comprising determining that the product is acceptable if the following conditions are met: 11. Immerse the chemically strengthened glass-ceramics in hot water at 80°C for 120 minutes and measure the mass change per surface area compared to before immersion; and The mass change per surface area is 8000 μg / cm 2 A test method for chemically strengthened crystallized glass, comprising determining that the product is acceptable if the following conditions are met:

[0114] The present invention will be described below with reference to examples, but the present invention is not limited thereto. [Example]

[0115] [Evaluation method] (Young's modulus E) Measurement was performed using an ultrasonic method.

[0116] (Fracture toughness value K IC ) Measurement was performed using the IF method in accordance with JIS R1607:2015.

[0117] (Hot water immersion test) The pure water was heated to 80°C to make it boiling water, and the glass (two test pieces for each test piece) was immersed in the boiling water for 30 minutes or 120 minutes. The mass of the glass was measured before and after the immersion, and the mass change and mass change rate per surface area were calculated. In Table 3, "Mass change per surface area in hot water immersion test (μg / cm 2 )" indicates the change in mass per surface area when immersed in hot water at 80°C for 120 minutes compared to before immersion. "Mass change rate (ppm) in hot water immersion test" in Table 3 indicates the mass change rate when immersed in 80°C hot water for 120 minutes compared to the mass before immersion.

[0118] (Average coefficient of linear expansion at 250 to 350°C) The linear expansion coefficient (α) was measured using a differential thermal dilatometer (TMA) and determined in accordance with the standard JIS R3102 (1995).

[0119] (Surface strength) The surface strength of the glass was measured using a ball-on-ring strength test. Figure 4 shows a schematic diagram illustrating the ball-on-ring strength test. A glass plate 1 was placed horizontally and pressed using a SUS304 pressure jig 2 (hardened steel, 10 mm diameter, mirror finish) to measure the surface strength of the glass plate. In Figure 4, a sample glass plate was placed horizontally on a SUS304 support jig 3 (30 mm diameter, 2.5 mm curvature radius at the contact point, hardened steel, mirror finish). Pressure jig 2 was installed above the glass plate to apply pressure to the glass plate. Pressure was applied to the central region of the resulting glass plate from above. The fracture load (unit: N) at which the glass plate broke was defined as the BoR surface strength, and the average value of 10 measurements was defined as the surface strength. However, if the fracture initiation point of the glass plate was more than 2 mm away from the ball pressing position, the data for calculating the average was excluded. The test conditions were as follows: Pressure jig descending speed: 1.0 (mm / min)

[0120] (X-ray diffraction: identification of precipitated crystals) Powder X-ray diffraction was measured under the following conditions to identify the precipitated crystals. Measurement equipment: Rigaku Smart Lab X-ray used: CuKα ray Measurement range: 2θ=10°~80° Speed: 1° / min Step: 0.01° (crystallinity) Powder X-ray diffraction was measured under the following conditions, and the crystallinity (unit: %) was calculated using the Rietveld method. Measurement equipment: Rigaku Corporation, Smart Lab X-ray used: CuKα ray Measurement range: 2θ=10°~80° Speed: 10° / min Step: 0.02°

[0121] (Stress profile) The stress profile was measured using a scattered light photoelastic stress meter SLP-2000 manufactured by Orihara Seisakusho.

[0122] [Reference example 1] Glass materials (amorphous glass or crystallized glass, 50mm x 50mm x 0.7mm) with different compositions and crystal types were prepared as shown in Table 1. They were immersed in 80°C hot water (immersion time: 30 minutes or 120 minutes), and the mass change per surface area was measured compared to before immersion. Furthermore, after immersion in 80°C hot water for 120 minutes, surface strength was measured using a BoR strength test. Figure 1 shows the mass change per surface area compared to before immersion when immersed in hot water (immersion time: 30 minutes or 120 minutes). Figure 2 and Table 2 show the results of measuring surface strength using a BoR strength test after immersing the glass materials in 80°C hot water for 120 minutes.

[0123] [Table 1]

[0124] [Table 2]

[0125] As shown in Figure 1, the mass change per surface area when immersed in boiling water varies depending on the composition and structure of the glass material (crystallized glass or amorphous glass, and the crystalline species contained in the crystallized glass), and it was found that the mass change is greater for crystallized glass than for amorphous glass. As shown in Figure 2 and Table 2, glass material A, which showed a large mass change per surface area when immersed in 80°C boiling water for 120 minutes compared to before immersion, showed a significant decrease in surface strength after immersion. These results show that there is a correlation between the mass change per surface area when immersed in 80°C boiling water for 120 minutes compared to before immersion and the surface strength of the glass when an environmental load is applied.

[0126] [Test Example 1] (1) Preparation and evaluation of amorphous glass Glass raw materials were mixed to obtain the glass composition shown in Table 3 in mole percent based on oxides, and weighed out to obtain 800 g of glass. The mixed glass raw materials were then placed in a platinum crucible and placed in an electric furnace at 1600°C, where they were melted for about 5 hours, degassed, and homogenized.

[0127] The resulting molten glass was poured into a mold and held at the glass transition temperature for 1 hour, after which it was cooled to room temperature at a rate of 0.5°C / min to obtain a glass block, which was then machined into a 50mm x 50mm x 0.7mm block and analyzed.

[0128] (2) Preparation and evaluation of glass-ceramics In Examples 2 to 11, the amorphous glass obtained in (1) above was heat-treated under the conditions shown in Table 3 to obtain crystallized glass. The crystallization conditions were two-stage, with treatment at a first treatment temperature at the temperature and time of nucleation treatment shown in Table 3, followed by treatment at a second treatment temperature at the temperature and time of nucleus growth treatment.

[0129] The resulting crystallized glass was processed and mirror-polished to obtain a crystallized glass plate with a thickness t of 0.7 mm, which was then analyzed. A rod-shaped sample was also prepared to measure the linear expansion coefficient. A portion of the remaining crystallized glass was crushed and used to analyze the precipitated crystals. The crystallized glass was evaluated for its average linear expansion coefficient at 250 to 350°C, degree of crystallization, crystal species, mass change and mass change rate per surface area in a hot water immersion test, and surface strength measured by a BoR test after immersion in 80°C hot water for 120 minutes. The results are shown in Table 3.

[0130] (3) Preparation and evaluation of chemically strengthened glass or chemically strengthened glass-ceramic The amorphous glass obtained in (1) above or the crystallized glass obtained in (2) above was immersed in molten sodium nitrate at 400°C for 60 minutes, and then the glass was washed with water, dried, and then immersed in molten potassium nitrate at 400°C for 60 minutes to perform ion exchange, thereby producing chemically strengthened glass or chemically strengthened crystallized glass, which was then analyzed.

[0131] The results of analyzing the amorphous glass, the crystallized glass, the chemically strengthened glass, and the chemically strengthened crystallized glass are shown in Table 3. In Table 3, Examples 1 to 4 are comparative examples, and Examples 5 to 11 are working examples.

[0132] [Table 3]

[0133] As shown in Table 3, the average linear expansion coefficient at 250 to 350°C is 90 × 10 -7 [ / K] or less, and the mass change per surface area in the hot water immersion test is 1500 μg / cm compared to before immersion. 2 The crystallized glasses of Examples 5, 7, 9 and 11 below were found to have higher surface strength after immersion in 80°C hot water for 120 minutes, superior weather resistance and less susceptible to deterioration of the surface condition due to environmental stress, compared to the amorphous glass of Comparative Example 1 and the crystallized glasses of Examples 3 and 4.

[0134] In addition, the average linear expansion coefficient at 250 to 350°C is 90 × 10 -7 [ / K] or less, and the mass change per surface area in the hot water immersion test is 8000μg / cm compared to before immersion. 2 The chemically strengthened crystallized glasses of Examples 5, 7, 9 and 11 shown below, which are the working examples, have higher surface strength after immersion in 80°C hot water for 120 minutes, are more weather resistant, and are less susceptible to deterioration of the surface condition due to environmental stress, compared to the chemically strengthened glass of Example 1 and the chemically strengthened crystallized glasses of Examples 3 and 4, which are comparative examples.

Claims

1. The matrix composition is expressed as mole percent based on oxides. SiO ２ 60 to 75%, Al ２ O ３ 3 to 20% and Li ２ Contains 5 to 25% O, Average linear expansion coefficient at 250 to 350°C is 90 x 10 －７ [ / K] or less, The mass change per surface area when immersed in hot water at 80°C for 120 minutes was 1500 μg / cm compared to before immersion. ２ The following is glass-ceramic:

2. Li as a crystal seed ２ Si ２ O ５ , LiAlSi ２ O ６ , LiAlSi ４ O １０ , Li ３ P.O. ４ 2. The crystallized glass according to claim 1, comprising at least one selected from the group consisting of β-quartz solid solution and β-quartz solid solution.

3. 2. The crystallized glass according to claim 1, having a Young's modulus of 70 GPa or more.

4. 2. The crystallized glass according to claim 1, which exhibits a mass change of 1000 ppm or less when immersed in hot water at 80°C for 120 minutes.

5. The matrix composition is expressed as mole percent based on oxides. SiO ２ 60 to 75% of Al ２ O ３ を3~20%、 P ２ O ５ More than 0% and 4.0% or less, Li ２ Oを5~25%、 Na ２ Oを0~2.0%、 K ２ O 0 to 1%, MgO 0 to 5%, CaO 0 to 2%, ZrO ２ More than 0% and less than 5% 2. The crystallized glass according to claim 1, wherein X calculated by the following formula is 0.40 or less. X = a × d ==[Li ２ O] / R ==[Li ２ O] / [SiO ２ ] R=[L) ２ O]+[[ ２ O]+[K ２ O] The value in [ ] indicates the content of the component in the brackets in the base composition, expressed as mole % on an oxide basis.

6. The base composition is expressed as mole percent based on oxides. SiO ２ 60 to 75%, Al ２ O ３ 3 to 20% and Li ２ Contains 5 to 25% O, Average linear expansion coefficient at 250 to 350°C is 90 x 10 －７ [ / K] or less, The mass change when immersed in hot water at 80°C for 120 minutes was 8000 μg / cm compared to before immersion. ２ Chemically strengthened glass-ceramics, which are as follows:

7. The plate thickness is t (mm), and the compressive stress layer depth DOC is 0.14t (μm) or more; Surface compressive stress value CS ０ is 400 MPa or more, Compressive stress value CS at a depth of 50 μm from the surface ５０ is 150t (MPa) or more, and The tensile stress value CT is −350t+400 (MPa) or less, The chemically strengthened glass-ceramics according to claim 6.

8. 7. The chemically strengthened glass-ceramics according to claim 6, having a Young's modulus of 70 GPa or more.

9. The base composition is expressed as mole percent based on oxides. SiO ２ 60 to 75% of Al ２ O ３ を3~20%、 P ２ O ５ More than 0% and 4.0% or less, Li ２ Oを5~25%、 Na ２ Oを0~2.0%、 K ２ O 0 to 1%, MgO 0 to 5%, CaO 0 to 2%, ZrO ２ More than 0% and less than 5% The chemically strengthened glass-ceramics according to claim 6, wherein X calculated by the following formula is 0.40 or less. X = a × d ==[Li ２ O] / R ==[Li ２ O] / [SiO ２ ] R=[L) ２ O]+[[ ２ O]+[K ２ O] The value in [ ] indicates the content of the component in the brackets in the base composition, expressed as mole % on an oxide basis.

10. Immerse the crystallized glass in hot water at 80 ° C. for 120 minutes and measure the mass change per surface area compared to before immersion; The mass change per surface area is 1500 μg / cm ２ A method for testing crystallized glass, comprising determining that the product is acceptable if the following conditions are met:

11. Immerse the chemically strengthened glass-ceramics in hot water at 80°C for 120 minutes and measure the mass change per surface area compared to before immersion; and The mass change per surface area is 8000 μg / cm ２ A test method for chemically strengthened crystallized glass, comprising determining that the product is acceptable if the following conditions are met:

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