Crystallised glass

Abstract

The present invention relates to crystallized glass that has a crystal phase and an amorphous phase. The crystallized glass contains, in mol% based on oxides, 55-70% of SiO2, 15-30% of Li2O, 1.0-4.5% of Al2O3, 0.5-5.0% of P2O5, 0.5-4.4% ZrO2, and more than 0% of SnO2. The crystallized glass satisfies 68.5-76.0% of SiO2, 1.0-5.0% of Al2O3, and 21.0-29.0% of Li2O relative to the total of SiO2, Al2O3, and Li2O. The content ratio of Li2Si2O5 crystals in the crystallized glass is 50-85 mass%.

Description

Glass-ceramics

[0001] The present invention relates to glass-ceramics.

[0002] Thin, high-strength chemically strengthened glass is used as cover glass for displays of electronic devices such as mobile phones, smartphones, and other mobile equipment. Chemically strengthened glass is produced by bringing glass into contact with a molten salt composition such as sodium nitrate to cause ion exchange between alkali metal ions contained in the glass and alkali metal ions with a larger ionic radius contained in the molten salt composition, thereby forming a compressive stress layer from the surface to the interior of the glass.

[0003] As an index of the strength of such a cover glass, Young's modulus and fracture toughness value K ＩＣ Glass-ceramics have been attracting attention as a way to realize high-strength cover glass with high values ​​for these properties. In particular, considering that chemical strengthening treatment is also performed, it is considered to apply Li-based glass-ceramics containing lithium to the cover glass.

[0004] As a crystalline phase in high-strength Li-based crystallized glass, lithium disilicate (Li ２ Si ２ O ５ For example, Patent Document 1 discloses a method for producing a silicon dioxide film using SiO ２ Ingredients, Al ２ O ３ Ingredients: Li ２ O component, ZrO ２ Ingredients, and P ２ O ５ Crystallized glass articles are disclosed that contain lithium silicate crystalline phases (one or both of lithium metasilicate and lithium disilicate) with component proportions within specified ranges.

[0005] Japanese Patent Application Publication No. 2023-506666

[0006] However, the inventors have found that increasing the crystallinity of the crystallized glass to achieve higher strength tends to decrease the transparency, and in particular, ２ Si ２ O ５ The crystals were found to be white and prone to becoming cloudy.

[0007] In fact, it has been found that the crystallized glass product disclosed in Patent Document 1 exhibits a decrease in transparency when the degree of crystallization is increased, and the desired transparency cannot be achieved.

[0008] In addition, since the crystalline phase of the crystallized glass depends on the composition (matrix composition) of the glass before crystallization, it is necessary to make the matrix composition close to the stoichiometric ratio of the target crystalline phase. ２ Si ２ O ５ The crystal has a composition in a region where phase separation is likely to occur, and the glass itself before crystallization tends to be cloudy and white. In addition to the above, if the chemical durability of the crystallized glass is low, the haze value tends to deteriorate, making it difficult to maintain transparency.

[0009] Therefore, an object of the present invention is to provide a new crystallized glass that has desired transparency and high strength, and is also capable of maintaining its transparency due to its excellent chemical resistance.

[0010] To solve the above problem, the composition of the mother glass before crystallization is adjusted to a specific range, thereby making it possible to obtain a high-strength Li-crystal. ２ Si ２ O ５ The inventors have come up with the idea of ​​obtaining a crystallized glass in which crystals are precipitated at a certain content or more, which can solve the above-mentioned problems.

[0011] That is, the gist of this embodiment relates to the following: [1] A crystallized glass having a crystalline phase and an amorphous phase, wherein the composition of the crystallized glass is expressed in mole percentage based on oxides as follows: SiO ２ 55-70%, Li ２ O 15-30%, Al ２ O ３ 1.0-4.5%, P ２ O ５ 0.5-5.0%, ZrO ２ 0.5 to 4.4%, and SnO ２ 0% or more, and ２ , Al ２ O ３ , and Li ２Using the content ratio of O expressed as mole percentage, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 1.0 to 5.0%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 21.0 to 29.0%, and the crystalline phase satisfies ２ Si ２ O ５ The Li in the glass-ceramics is ２ Si ２ O ５ [2] A crystallized glass having a crystalline phase and an amorphous phase, wherein the composition of the crystallized glass is SiO 2 expressed in mole percentage on an oxide basis. ２ , Al ２ O ３ , and Li ２ Using the content ratio of O, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 1.0 to 5.0%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li２ O] × 100} is 21.0 to 29.0%, and the crystalline phase satisfies ２ Si ２ O ５ The Li in the glass-ceramics is ２ Si ２ O ５ The content of the crystal is 50 to 85 mass %, and the composition of the amorphous phase is expressed in mole percentage on an oxide basis as follows: SiO ２ 50-72%, Li ２ O 0.1-15%, Al ２ O ３ 3-15%, P ２ O ５ 1 to 10% ZrO ２ 1 to 15% SnO ２ 0.01-5%, Na ２ O 1-18% and K ２ [3] The composition of the glass-ceramics satisfies, in mole percentage based on oxides, SiO ２ 55-70%, Li ２ O 15-30%, Al ２ O ３ 1.0-4.5%, P ２ O ５ 0.5-5.0%, ZrO ２ 0.5 to 4.4%, and SnO ２ [4] The composition of the crystallized glass according to [2] satisfies, in mole percentage based on oxides, Na ２ O 0.1 to 5%, and K ２ [5] The crystallized glass according to any one of [1] to [3], further satisfying the following: Li 0 to 3%. ２ Si ２ O ５ The crystallized glass according to any one of [1] to [4], wherein the content of crystals other than crystals is 10 mass % or less. [6] The composition of the crystallized glass is SiO 2 expressed in mole percentage based on oxides. ２ , Al ２ O３ , and Li ２ The crystallized glass according to any one of the above [1] to [5], wherein the total content of O is 90% or more. [7] Fracture toughness value K ＩＣ is 1.3 MPa m １／２ [8] The glass-ceramics according to any one of [1] to [6], having a Young's modulus of 95 to 120 GPa. [9] The glass-ceramics according to any one of [1] to [8], having a haze value of 0.03 to 0.29% when converted into a thickness of 0.6 mm.

[10] The glass-ceramics according to any one of [1] to [9], having an average transmittance of 85% or more for light with a wavelength of 380 to 780 nm when converted into a thickness of 0.6 mm.

[11] The glass-ceramics according to any one of [1] to

[10] , having an average crystallite size of 20 to 200 nm for crystals constituting the crystalline phase.

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

[11] , wherein the difference in the haze value (%) converted to a thickness of 0.6 mm after immersion in 0.1 mol% hydrochloric acid at 90°C for 20 hours is 0.05% or less.

[13] The crystallized glass according to any one of [1] to

[12] , wherein the difference in the haze value (%) converted to a thickness of 0.6 mm after immersion in 0.1 mol% aqueous sodium hydroxide solution at 90°C for 20 hours is 3% or less.

[14] The crystallized glass according to any one of [1] to

[13] , wherein the surface layer has a compressive stress layer formed by ion exchange.

[15] The compressive stress value CS at the outermost surface ０

[16] The glass-ceramics according to any one of [1] to

[15] , wherein the compressive stress layer depth DOL is 50 μm or more.

[17] The glass-ceramics according to any one of [1] to

[16] , wherein the compressive stress layer depth DOL is {t × 0.13} μm or more, where t is the thickness of the glass (μm).

[0012] According to the present invention, a new crystallized glass can be obtained which has desired transparency and high strength, and which is also capable of maintaining its transparency due to its excellent chemical resistance.

[0013] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the embodiments described below. In this specification, the term "to" indicating a range of values ​​is used to mean that the values ​​before and after it are included as the lower and upper limits. Furthermore, in this specification, mass % and weight %, and parts by mass and parts by weight have the same meaning.

[0014] <<Ceramics>> The crystallized glass according to this embodiment has a crystalline phase and an amorphous phase, and the crystalline phase is Li ２ Si ２ O ５ The above Li crystals are included. ２ Si ２ O ５ The content of the crystals in the crystallized glass is 50% by mass or more, preferably 50 to 85% by mass.

[0015] The crystallized glass according to this embodiment is made of SiO ２ , Al ２ O ３ , and Li ２ SiO relative to the total content of O expressed in mole percentage ２ , Al ２ O ３ , and Li ２ The content ratio of each of the O is within the following ranges: ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 1.0 to 5.0%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 21.0 to 29.0%.

[0016] In addition to the above requirements, the composition of the crystallized glass according to this embodiment preferably satisfies the following in terms of mole percentage based on oxides: SiO ２ 55-70%, Li ２ O 15-28%, Al ２ O ３ 1.0-4.5%, P ２ O ５ 0.5-5%, ZrO ２ 0.5 to 4.4%, and SnO ２ More than 0%.

[0017] In addition to the above requirements, it is also preferable that the composition of the amorphous phase in the crystallized glass according to this embodiment satisfies the following in terms of mole percentage based on oxides: SiO ２ 50-72%, Li ２ O 0.1-15%, Al ２ O ３ 3-15%, P ２ O ５ 1 to 10% ZrO ２ 1 to 15% SnO ２ 0.01-5%, Na ２ O 1-18%, and K ２ O 0-7%.

[0018] In addition to the above requirements, it is more preferable that the composition of the crystallized glass satisfies the above requirements and that the composition of the amorphous phase satisfies the above requirements.

[0019] The composition of the crystallized glass in this specification is the same as the composition (mother composition) of the amorphous glass (mother glass) before crystallization. The composition of the amorphous phase in the crystallized glass can be determined from the composition of the crystallized glass and the composition and content of the crystalline phase of the crystallized glass.

[0020] The composition of the crystallized glass can be identified by a conventionally known method, for example, by wet chemical analysis or quantitative analysis using a fluorescent X-ray calibration curve.

[0021] Glass-ceramics can be determined to have a crystalline phase by observing diffraction peaks indicating crystals in an XRD pattern obtained by powder X-ray diffraction (XRD). The glass-ceramics have a crystalline phase in which crystals are precipitated by heat-treating amorphous glass (mother glass) in which no diffraction peaks indicating crystals are observed. The XRD measurement is performed using CuKα radiation in the 2θ range of 10° to 80°.

[0022] The composition and content of the crystalline phase in the crystallized glass can be determined by Rietveld analysis from the XRD pattern and diffraction intensity. 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). When the crystalline phase is composed of one type of crystal, the content of that crystal is the crystallinity, and when multiple crystals are present, the total content of those crystals is the crystallinity.

[0023] The crystallized glass according to this embodiment contains Li as a crystalline phase. ２ Si ２ O ５ The Li in the crystallized glass is ２ Si ２ O ５ The content of crystals is 50% by mass or more, and SiO ２ , Al ２ O ３ , and Li ２ It has been found that the problem of the present invention can be solved by the ratio expressed by the content ratio of O expressed in mole percentage satisfying the above relationship, and also by the composition of at least one of the crystallized glass and the composition of the amorphous phase satisfying the above range.

[0024] <Composition of Crystallized Glass> As described above, the composition of the crystallized glass according to this embodiment is SiO ２ , Al ２ O ３ , and Li ２ Using the content ratio of O expressed as mole percentage, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O３ ]+[Li ２ O]) × 100} is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 1.0 to 5.0%, and ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 21.0 to 29.0%.

[0025] The composition of the crystallized glass preferably satisfies the following in terms of mole percentage based on oxides: SiO ２ 55-70%, Li ２ O 15-28%, Al ２ O ３ 1.0-4.5%, P ２ O ５ 0.5-5%, ZrO ２ 0.5 to 4.4%, and SnO ２ More than 0%.

[0026] In addition to the above, the composition of the crystallized glass is expressed in mole percentage based on oxides: Na ２ O 0.1 to 5%, and K ２ It is more preferable to further satisfy at least one of the above conditions, and it is even more preferable to further satisfy both of the above conditions.

[0027] Each component will be described below.

[0028] SiO ２ is a component that constitutes the glass network, and Li ２ Si ２ O ５ It is also a component that forms crystals. SiO in crystallized glass ２ The content of Li is preferably 55 to 70%, more preferably 60 to 69%, and even more preferably 62 to 68%. ２ Si ２ O５ From the viewpoint of facilitating crystal formation, the content is preferably 55% or more, more preferably 60% or more, even more preferably 62% or more, even more preferably 64% or more, and particularly preferably 66% or more. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and enhancing the meltability of the glass, the content is preferably 70% or less, more preferably 69.5% or less, even more preferably 69% or less, and even more preferably 68% or less.

[0029] Li ２ O is Li ２ Si ２ O ５ It is a component of crystals and is also a component that forms compressive stress near the surface of crystallized glass by ion exchange with Na ions. ２ The content of O is preferably 15 to 30%, more preferably 16 to 28%, and even more preferably 17 to 27%. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and increasing compressive stress, the content is preferably 15% or more, more preferably 16% or more, even more preferably 17% or more, even more preferably 18% or more, and particularly preferably 20% or more. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and the chemical durability of the glass, the content is preferably 30% or less, more preferably 28% or less, even more preferably 27% or less, even more preferably 26% or less, and particularly preferably 25% or less.

[0030] Al ２ O ３ is a component that improves ion exchangeability during chemical strengthening treatment and increases the surface compressive stress after chemical strengthening treatment. ２ O ３The content ratio is preferably 1.0 to 4.5%, more preferably 1.3 to 4.2%, and even more preferably 1.6 to 3.8%. Here, from the viewpoint of performing chemical strengthening treatment appropriately, the content ratio is preferably 1.0% or more, more preferably 1.3% or more, and even more preferably 1.6% or more, and may be 2.2% or more, 2.3% or more, 2.4% or more, 2.5% or more, or 2.6% or more. In addition, Li ２ Si ２ O ５ From the viewpoint of facilitating crystal formation, the content is preferably 4.5% or less, more preferably 4.2% or less, even more preferably 3.8% or less, may be 3.4% or less, may be 3.0% or less, may be 2.8% or less, or may be 2.6% or less.

[0031] P ２ O ５ is a component that promotes crystallization. ２ O ５ The content is preferably 0.5 to 5.0%, more preferably 0.8 to 4.0%, and even more preferably 0.9 to 3.0%. From the viewpoint of facilitating crystallization, the content is preferably 0.5% or more, more preferably 0.8% or more, and even more preferably 0.9% or more, and may be 1.0% or more, 1.1% or more, or 1.2% or more. Furthermore, from the viewpoint of suppressing phase separation during melting and a decrease in acid resistance, the content is preferably 5.0% or less, more preferably 4.0% or less, even more preferably 3.0% or less, and even more preferably 2.0% or less.

[0032] ZrO ２ is a thickening component that increases the viscosity when melted, and at the same time, is a component that increases the surface compressive stress due to ion exchange. ２ It has been found that by adding an appropriate amount of ZrO, it is possible to suitably control phase separation so that crystallization is facilitated while maintaining high transparency. As a result, when the glass is made into a crystallized glass, the crystallization degree can be increased while maintaining high transparency, and higher strength can be achieved. ２The content ratio is preferably 0.5 to 4.4%, more preferably 1.0 to 4.2%, and even more preferably 1.5 to 4.0%. Here, from the viewpoint of controlling phase separation and acting as a thickening component to slow the growth rate of crystals that become crystalline phases and form fine crystals, thereby realizing higher transparency of the crystallized glass, the content ratio is preferably 0.5% or more, more preferably 1.0% or more, even more preferably 1.5% or more, and may be 1.6% or more, 1.8% or more, or 2.0% or more. Furthermore, from the viewpoint of suppressing devitrification during melting, the content ratio is preferably 4.4% or less, may be 4.2% or less, may be 4.0% or less, or may be 3.8% or less.

[0033] In addition, ZrO in the chemically strengthened glass according to this embodiment ２ The content ratio is preferably 1 to 10 mass% when expressed as a mass percentage based on oxides. Here, from the viewpoint of controlling phase separation and acting as a thickening component to slow the growth rate of crystals that become crystalline phases and form fine crystals, thereby realizing higher transparency of the crystallized glass, the content ratio is preferably 1 mass% or more, more preferably 2.5 mass% or more, even more preferably 3.2 mass% or more, and even more preferably 3.7 mass% or more. Furthermore, from the viewpoint of suppressing devitrification during melting, the content ratio is preferably 10 mass% or less, more preferably less than 5 mass%, even more preferably 4.8 mass% or less, and may be 4.5 mass% or less, or may be 4.4 mass% or less.

[0034] SnO ２ is a fining agent during melting and also a component that generates crystal nuclei. ２ It has been found that the inclusion of SnO in the glass-ceramics can improve chemical resistance such as acid resistance and alkali resistance. ２ The content of SnO is preferably more than 0%, more preferably more than 0% and not more than 1.00%, further preferably 0.01 to 0.50%, and even more preferably 0.05 to 0.40%. ２The content of is preferably more than 0%, but from the viewpoint of realizing the high transparency of crystallized glass by acting as the component that generates the nucleus of crystal, and by making it into minute crystal, and from the viewpoint of chemical resistance, the content is more preferably 0.01% or more, more preferably 0.05% or more, more preferably 0.10% or more, particularly preferably 0.50% or more.In addition, from the viewpoint of suppressing the defect caused by unmelted matter, the content is preferably 1.00% or less, more preferably 0.50% or less, more preferably 0.40% or less.

[0035] In addition, ZrO, which is a nucleation material, ２ , SnO ２ , and TiO ２ SnO relative to the total content ２ The ratio of the content ratio of SnO ２ ] / ([ZrO ２ ]+[SnO ２ ]+[TiO ２ ]) × 100} (%) is preferably 0.1 to 5.0%. From the viewpoint of chemical resistance, the ratio is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.3% or more, even more preferably 0.4% or more, may be 0.5% or more, or may be 1.0% or more. From the viewpoint of suppressing coloration of the glass, the ratio is preferably 5.0% or less, more preferably 4.0% or less, and even more preferably 3.0% or less.

[0036] Na ２ O is a component that forms compressive stress by ion-exchanging with K ions, and the inclusion of a small amount of O can increase the stability of the glass. ２ The content of O is preferably 0 to 5%, more preferably 0.1 to 5%, even more preferably 0.5 to 4.5%, even more preferably 1.0 to 4%, and particularly preferably 1.5 to 3.5%. ２ The content of O is 0%, that is, it may not be contained, but Na ２When O is contained, from the viewpoint of increasing the compressive stress and improving the stability of the glass, the content is preferably 0.1% or more, more preferably 0.5% or more, even more preferably 1.0% or more, even more preferably 1.5% or more, or may be 2.0% or more, or may be 2.5% or more. Furthermore, from the viewpoint of maintaining chemical durability, the content is preferably 5% or less, more preferably 4.5% or less, even more preferably 4% or less, and even more preferably 3.5% or less.

[0037] K ２ O is a component that enhances chemical strengthening properties and suppresses phase separation. ２ The content of O is preferably 0 to 3%, more preferably 0.1 to 3%, and even more preferably 0.2 to 2.5%. ２ The content of O is 0%, that is, it may not be contained, but K ２ When O is contained, the content is preferably 0.1% or more, more preferably 0.2% or more, and even more preferably 0.4% or more from the viewpoint of enhancing the stability of the glass, and is preferably 3% or less, more preferably 2.5% or less from the viewpoint of maintaining chemical durability.

[0038] The alkaline earth metals MgO, CaO, SrO, and BaO are components that enhance the meltability of glass. The total content of MgO, CaO, SrO, and BaO is preferably 0 to 5.0%, more preferably 0.1 to 4.0%, and even more preferably 0.5 to 3.0%. Although alkaline earth metals are not required, if they are contained, from the viewpoints of meltability and strength, the total content is preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and even more preferably 1.0% or more. Furthermore, from the viewpoint of maintaining good ion exchange performance, the total content is preferably 5.0% or less, more preferably 4.0% or less, even more preferably 3.0% or less, even more preferably 2.0% or less, and particularly preferably 1.0% or less.

[0039] The respective contents of MgO, CaO, SrO, and BaO are preferably 0 to 4.0%, more preferably 0.1 to 3.0%, even more preferably 0.2 to 2.5%, even more preferably 0.5 to 2.0%, and particularly preferably 1.0 to 2.0%. MgO, CaO, SrO, and BaO may not be contained, but if they are contained, from the viewpoint of enhancing the stability of the glass, the respective contents are preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, and even more preferably 1.0% or more. From the viewpoint of maintaining good ion exchange performance, the respective contents are preferably 4.0% or less, more preferably 3.0% or less, even more preferably 2.5% or less, and even more preferably 2.0% or less.

[0040] Y ２ O ３ Y is a thickening component that increases the viscosity during melting, and at the same time, it is a component that increases the mechanical strength of the glass. It is also a component that increases the refractive index. ２ O ３ The content of Y is preferably 0 to 5%, more preferably 0.1 to 3%, and even more preferably 0.3 to 1%. ２ O ３ Although it is not necessary to contain, when it is contained, it acts as a thickening component, slows down the crystal growth rate of crystalline phase, makes minute crystals, and from the viewpoint of realizing the high transparency of crystallized glass, the above-mentioned content ratio is preferably 0.1% or more, more preferably 0.3% or more.In addition, from the viewpoint of suppressing mismatch during melting, the above-mentioned content ratio is preferably 5% or less, more preferably 3% or less, even more preferably 1% or less, and particularly preferably 0.5% or less.

[0041] TiO ２ is a thickening component that increases the viscosity when melted, and at the same time, is a component that increases UV resistance. ２ The content of TiO is preferably 0 to 5%, more preferably 0.1 to 4%, and even more preferably 0.5 to 3%. ２Although it is not necessary to contain, when it is contained, it acts as a thickening component, slows down the growth rate of the crystals that become crystalline phase, and makes them into minute crystals, so that the high transparency of the crystallized glass can be realized, and the content ratio is preferably 0.1% or more, more preferably 0.5% or more.In addition, from the viewpoint of suppressing the decrease in haze value due to coloring, the content ratio is preferably 5% or less, more preferably 4% or less, and even more preferably 3% or less.

[0042] ZnO is a component that improves the meltability of glass. The ZnO content in the crystallized glass is preferably 0 to 5%, more preferably 0.1 to 4%, and even more preferably 0.2 to 1%. While ZnO need not be included, if it is included, from the viewpoint of obtaining good meltability, the content is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 1.0% or more. Furthermore, from the viewpoint of improving weather resistance, the content is preferably 5% or less, more preferably 4% or less, even more preferably 1% or less, even more preferably 0.7% or less, and particularly preferably 0.5% or less.

[0043] B ２ O ３ is a component that improves chipping resistance and melting property. ２ O ３ The content of B is preferably 0 to 10%, more preferably 0.1 to 5%, and even more preferably 0.2 to 2%. ２ O ３ Although it is not necessary to contain it, if it is contained, from the viewpoint of obtaining good chipping resistance and melting property, the content ratio is preferably 0.1% or more, more preferably 0.2% or more. Furthermore, from the viewpoint of suppressing the occurrence of striae and phase separation during melting and maintaining the quality of the crystallized glass, the content ratio is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less.

[0044] La ２ O ３ , Nb ２ O ５ and Ta ２ O ５ Is Y ２ O ３Similarly to La, it has the effect of increasing the mechanical strength of the glass and may be contained to increase the refractive index. ２ O ３ , Nb ２ O ５ and Ta ２ O ５ The total content of these components is preferably 0 to 3%, more preferably 0.5 to 2%. These components do not necessarily have to be contained, but if they are contained, the total content is preferably 0.5% or more from the viewpoint of increasing the refractive index. Furthermore, the total content is preferably 3% or less, more preferably 2% or less from the viewpoint of suppressing devitrification of the glass during melting.

[0045] CeO ２ has the effect of oxidizing the glass, and the glass-ceramic becomes SnO ２ When the content is large, SnO ２ The reduction of CeO in the glass-ceramics to SnO, which is a coloring component, can be suppressed, thereby suppressing coloration. ２ The content of CeO is preferably 0 to 1.5%, more preferably 0.03 to 1.5%, even more preferably 0.05 to 1%, and even more preferably 0.07 to 1%. ２ However, if it is contained, the content is preferably 0.03% or more, more preferably 0.05% or more, and even more preferably 0.07% or more, from the viewpoint of suppressing coloration due to SnO. ２ From the viewpoint of suppressing coloration of the glass due to the presence of arsenic, the content is preferably 1.5% or less, and more preferably 1% or less.

[0046] Furthermore, a coloring component may be contained in the glass-ceramics to the extent that it does not hinder the achievement of the desired properties. ３ O ４ , MnO ２ , Fe ２ O ３ , NiO, CuO, Cr ２ O ３ , V ２ O ５ , Bi ２ O ３ , SeO ２, Er ２ O ３ , Nd ２ O ３ etc. The content ratio of the above coloring components in the crystallized glass is preferably in the range of 1% or less in total. Furthermore, if it is desired to increase the light transmittance of the crystallized glass, it is preferable that these components are not substantially contained. In this specification, "substantially not contained" means that the content is below the impurity level contained in raw materials, etc., that is, it is not intentionally added. In this specification, when it is stated that a certain component is not substantially contained, the content ratio of the component is specifically, for example, less than 0.01%.

[0047] In addition, SO is used as a fining agent when melting glass. ３ , chloride, fluoride, As ２ O ３ , Sb ２ O ３ When a clarifier is contained, the content of each is preferably 0.3% or less, more preferably 0.1% or less, and most preferably substantially none is contained.

[0048] The composition of the crystallized glass according to this embodiment is SiO ２ , Al ２ O ３ , and Li ２ The values ​​expressed by the following formulas using the content ratio of O expressed in mole percentage are within the respective predetermined ranges: {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 68.5 to 76.0%, ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is 1.0 to 5.0%, ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２O] × 100} is 21.0 to 29.0%.

[0049] Each of the above formulas represents SiO ２ , Al ２ O ３ , and Li ２ SiO relative to the total content of O ２ , Al ２ O ３ , or Li ２ The content ratio of each component, such as O.

[0050] SiO ２ , Al ２ O ３ , and Li ２ The total content of O means the total content ratio of components that easily form crystals in the crystallized glass. ２ 68.5 to 76.0%, Al ２ O ３ 1.0 to 5.0%, and Li ２ By containing 21.0 to 29.0% of O, Li ２ Si ２ O ５ It was found that crystals were selectively precipitated, and a crystallized glass having a crystal content of 50 to 85 mass % was obtained, and as a result, high strength could be achieved while maintaining the desired transparency.

[0051] The SiO ２ The content ratio of is 68.5 to 76.0%, preferably 69.0 to 74.5%. Here, the content ratio is 68.5% or more, and Li ２ Si ２ O ５ From the viewpoint of facilitating crystal formation, the content is preferably 69.0% or more, more preferably 70.0% or more, and even more preferably 71.0% or more. ２ Si ２ O ５ From the viewpoint of facilitating crystal formation and enhancing the meltability of the glass, the content is preferably 74.5% or less, more preferably 73.0% or less, and even more preferably 71.5% or less.

[0052] The above Al ２ O３ The content ratio is 1.0 to 5.0%, preferably 1.3 to 4.7%. Here, the content ratio is 1.0% or more, and from the viewpoint of suppressing phase separation during the production of amorphous glass and improving ion exchangeability during chemical strengthening treatment, it is preferably 1.3% or more, more preferably 1.5% or more, even more preferably 2.0% or more, even more preferably 2.2% or more, and may be 2.4% or more, or may be 2.5% or more. Furthermore, the content ratio is 5.0% or less, and SiO ２ , Al ２ O ３ , Li ２ From the viewpoint of suppressing the precipitation of crystals composed of O, the content is preferably 4.7% or less, more preferably 4.4% or less, even more preferably 4.0% or less, and even more preferably 3.8% or less.

[0053] The above Li ２ The content of O is 21.0 to 29.0%, preferably 23.0 to 28.5%. Here, the content is 21.0% or more, and Li ２ Si ２ O ５ From the viewpoint of facilitating crystal formation, the content is preferably 23.0% or more, more preferably 25.0% or more, and even more preferably 27.0% or more. In addition, the content is 29.0% or less, and after the crystallization treatment, Li ２ SiO ３ From the viewpoint of suppressing residual crystals, the content is preferably 28.6% or less, more preferably 28.5% or less, even more preferably 28.3% or less, even more preferably 28.2% or less, and may be 28.1% or less.

[0054] In addition, SiO in the crystallized glass ２ , Al ２ O ３ , and Li ２ The total content of O is preferably 90% or more, more preferably 90 to 96%. ２ Si ２ O ５From the viewpoint of facilitating crystal formation, the total content is preferably 90% or more, more preferably 91% or more, even more preferably 92% or more, and even more preferably 93% or more. Also, from the viewpoint of improving ion exchangeability during chemical strengthening treatment, the total content is preferably 96% or less, even more preferably 95% or less, even more preferably 94% or less, and particularly preferably 93.5% or less.

[0055] Li of the crystallized glass according to this embodiment ２ O and ZrO ２ Using the content of {[Li ２ O] / [ZrO ２ ]} is preferably 8 or more, more preferably 8 to 20. Here, the value of the ratio serves as an index of Li ion exchange properties and alkali resistance. Among these viewpoints, from the viewpoint of improving the Li ion exchange properties, the value of the ratio is preferably 8 or more, more preferably 9 or more, even more preferably 11 or more, and particularly preferably 13 or more. Furthermore, from the viewpoint of improving the alkali resistance, the value of the ratio is preferably 20 or less, more preferably 17 or less, even more preferably 15 or less, and particularly preferably 14 or less.

[0056] The Al of the crystallized glass according to this embodiment ２ O ３ and ZrO ２ Using the content of {[Al ２ O ３ ] / [ZrO ２ The value of the ratio represented by {\displaystyle \mathbb {R}} is preferably 0.7 to 3.0. Here, the value of the ratio serves as an index of the K ion and Na ion exchange properties. From this viewpoint, the value of the ratio is preferably 0.7 or more, more preferably 0.8 or more, even more preferably 0.9 or more, even more preferably 1.0 or more, and particularly preferably 1.1 or more. Moreover, the value of the ratio is preferably 3.0 or less, more preferably 2.0 or less, even more preferably 1.5 or less, and even more preferably 1.2 or less.

[0057] <Composition of Amorphous Phase> The composition of the amorphous phase in the crystallized glass according to this embodiment is the above-mentioned SiO ２ , Al ２ O ３ , and Li ２SiO relative to the total content of O ２ , Al ２ O ３ , or Li ２ There are no particular limitations as long as the content ratio of each component of O satisfies a predetermined range. However, since crystallized glass is obtained by subjecting mother glass to crystallization treatment, the composition of the amorphous phase is naturally determined to some extent in accordance with the content ratio of each component of the crystallized glass.

[0058] As one aspect thereof, it is preferable that the composition of the amorphous phase in this embodiment, expressed in mole percentage based on oxides, satisfies the following: SiO ２ 50-72%, Li ２ O 0.1-15%, Al ２ O ３ 3-15%, P ２ O ５ 1 to 10% ZrO ２ 1 to 15%, and SnO ２ 0.01 to 5%.

[0059] In addition to the above, the composition of the amorphous phase is expressed as mole percentage based on oxides: Na ２ O 1-18%, and K ２ It is more preferable to further satisfy at least one of the above conditions, and it is even more preferable to further satisfy both of the above conditions.

[0060] Each component in the amorphous phase will be described below, and the reasons for determining the role and preferred range of each component are the same as those for determining the role and preferred range of each component in the crystallized glass.

[0061] SiO in the amorphous phase ２ The content is preferably 50 to 72%, more preferably 55 to 70%. Here, the content is preferably 50% or more, more preferably 55% or more, and even more preferably 58% or more, and is preferably 72% or less, more preferably 70% or less, even more preferably 65% ​​or less, and even more preferably 60% or less.

[0062] Li in the amorphous phase ２The O content is preferably 0.1 to 15%, more preferably 0.5 to 12%. Here, the O content is preferably 0.1% or more, more preferably 0.5% or more, even more preferably 1% or more, even more preferably 2% or more, and is preferably 15% or less, more preferably 12% or less, and even more preferably 8% or less.

[0063] Al in the amorphous phase ２ O ３ The content is preferably 3 to 15%, more preferably 5 to 13%. Here, the content is preferably 3% or more, more preferably 5% or more, even more preferably 8% or more, even more preferably 9% or more, and is preferably 15% or less, more preferably 13% or less, and even more preferably 11% or less.

[0064] P in the amorphous phase ２ O ５ The content is preferably 1 to 10%, more preferably 3 to 8%. Here, the content is preferably 1% or more, more preferably 3% or more, even more preferably 4% or more, even more preferably 6% or more, and is preferably 10% or less, more preferably 8% or less, and even more preferably 7% or less.

[0065] ZrO in the amorphous phase ２ The content is preferably 1 to 15%, more preferably 4 to 12%. Here, the content is preferably 1% or more, more preferably 4% or more, even more preferably 7% or more, even more preferably 9% or more, and is preferably 15% or less, more preferably 12% or less, and even more preferably 10% or less.

[0066] SnO in the amorphous phase ２ The content is preferably 0.01 to 5%, more preferably 0.03 to 4.50%. Here, the content is preferably 0.01% or more, more preferably 0.03% or more, even more preferably 0.05% or more, even more preferably 0.30% or more, particularly preferably 1.00% or more, and is preferably 5% or less, more preferably 4.50% or less, and even more preferably 4.20% or less.

[0067] Na in the amorphous phase ２The O content is preferably 1 to 18%, more preferably 3 to 15%. Here, the O content is preferably 1% or more, more preferably 3% or more, even more preferably 6% or more, even more preferably 10% or more, and is preferably 18% or less, more preferably 15% or less, and even more preferably 12% or less.

[0068] K in the amorphous phase ２ The content of O is preferably 0 to 7%, more preferably 1 to 5%. ２ The content of O is 0%, that is, it may not be contained, but K ２ When O is contained, the content is preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more, and is preferably 7% or less, more preferably 5% or less, and even more preferably 4% or less.

[0069] The total content of alkaline earth metals in the amorphous phase, i.e., the total content of MgO, CaO, SrO, and BaO, is preferably 0 to 7%, and more preferably 1 to 5%. Here, the total content of alkaline earth metals may be 0%, i.e., no alkaline earth metals are necessary, but when alkaline earth metals are contained, the total content is preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more, and is preferably 7% or less, more preferably 5% or less, even more preferably 4% or less, and even more preferably 3% or less.

[0070] The content of each of MgO, CaO, SrO, and BaO in the amorphous phase is preferably 0 to 5%, and more preferably 1 to 4%. Here, the content of MgO, CaO, SrO, and BaO may be 0%, i.e., they may not be contained, but when MgO, CaO, SrO, and BaO are contained, the content of each is preferably 1% or more, more preferably 2% or more, or may be 3% or more, and is preferably 5% or less, more preferably 4% or less, or may be 3% or less.

[0071] The amorphous phase in this embodiment may contain other components in the same manner as crystallized glass, as long as the desired properties are not impaired.

[0072] <Crystalline Phase> The crystallized glass according to this embodiment has a crystalline phase of Li２ Si ２ O ５ It has crystals. ２ Si ２ O ５ The content of the crystals in the crystallized glass is 50% by mass or more, preferably 50 to 85% by mass. Here, from the viewpoint of realizing higher strength, the content is 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. Furthermore, from the viewpoint of maintaining higher transparency and three-dimensional formability, the content is preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less.

[0073] In this embodiment, the crystalline phase is Li ２ Si ２ O ５ The crystals may further include other crystals, such as β-spodumene crystals (LiAlSi ２ O ６ ), petalite (LiAlSi ４ O １０ ), β-quartz (including bergerite) (Li ｘ Al ｘ Si ３－ｘ O ６ ), lithium metasilicate (Li ２ SiO ３ ), eucryptite (LiAlSiO ４ ), mullite (Al ４＋２ｘ Si ２－２ｘ O １０－ｘ , 0.2≦x≦0.5), lithium phosphate (Li ３ P.O. ４ However, the present invention is not limited to these and may be appropriately selected according to the desired properties.

[0074] For example, when it is desired to obtain a crystalline phase that can be ion-exchanged by chemical strengthening treatment, Li ２ Si ２ O ５ It may be composed of crystals only, but may also contain β-spodumene crystals, petalite, β-quartz, lithium metasilicate, and the like.

[0075] When it is desired to obtain a crystallized glass with higher strength, Li ２ Si ２ O ５ It may be composed of crystals only, but may also contain β-spodumene crystals, petalite, β-quartz, lithium metasilicate, mullite, etc.

[0076] If you want to achieve higher transparency, ２ Si ２ O ５ The material may be composed of crystals only, but may also contain β-quartz, lithium metasilicate, lithium phosphate, or the like.

[0077] In the crystallized glass according to this embodiment, the Li ２ Si ２ O ５ The content of crystals other than crystals is preferably 10% by mass or less, more preferably 0 to 10% by mass. ＩＣ The strength of the glass-ceramics depends on the amount of Li rather than the total amount of crystalline phase (crystallinity). ２ Si ２ O ５ Therefore, from the viewpoint of more suitably realizing an improvement in strength, the amount of Li in the crystallized glass was found to be more dominant. ２ Si ２ O ５ The total content of crystals other than the crystals is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less. The lower limit is not particularly limited, and it is possible to set the lower limit to 0% by mass, i.e., the total amount of the crystal phase is Li. ２ Si ２ O ５ It may be a crystal, and when it contains other crystals, it may be 1% by mass or more, or 2% by mass or more.

[0078] The content ratio of the crystalline phase in the crystallized glass according to this embodiment, i.e., the degree of crystallization, is not particularly limited. ２ Si ２ O ５Since the content of crystals is 50% by mass or more, the crystallinity is also 50% by mass or more. The crystallinity may be 50 to 85% by mass, or 60 to 80% by mass. Here, the crystallinity may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 85% by mass or less, 80% by mass or less, or 75% by mass or less. Note that the crystalline phase may contain Li. ２ Si ２ O ５ When crystals other than the crystals are also contained, the total content of these crystals is the above-mentioned crystallinity.

[0079] The crystallinity in volume fraction of the crystallized glass according to this embodiment may be 60 to 90% by volume, or 65 to 85% by volume. Here, from the viewpoint of increasing the mechanical strength of the crystallized glass, the crystallinity is preferably 60% by volume or more, more preferably 65% ​​by volume or more, and even more preferably 70% by volume or more. Furthermore, from the viewpoint of maintaining high transmittance and low haze value, and from the viewpoint of three-dimensional formability, the crystallinity may be 90% by volume or less, 85% by volume or less, or 80% by volume or less.

[0080] The crystallized glass according to this embodiment has a powder X-ray diffraction pattern (XRD pattern) using Cu-Kα radiation, in which Li is present in the range of 2θ=23.5 to 25.5°. ２ Si ２ O ５ The half-value width of the peak in the upper range where a peak derived from crystals is observed is preferably 0.1 to 0.4. The half-value width is related to the degree of crystallinity and the crystallite size, and the higher the degree of crystallinity, the narrower the half-value width. Also, the smaller the crystallite size, the narrower the half-value width. In light of this tendency, the half-value width is preferably 0.4 or less, more preferably 0.3 or less, even more preferably 0.25 or less, and is preferably 0.1 or more.

[0081] In this embodiment, the average crystallite size of the crystals constituting the crystalline phase is preferably 20 to 200 nm. From the viewpoint of achieving higher strength, the average crystallite size is preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 40 nm or more. From the viewpoint of achieving higher transparency, the average crystallite size is preferably 200 nm or less, more preferably 150 nm or less, and even more preferably 100 nm or less. The average crystallite size can be measured by observation with a scanning electron microscope (SEM). The average crystallite size can also be adjusted by adjusting the heat treatment conditions for crystallization.

[0082] <Characteristics and Physical Properties> Fracture toughness value K of the crystallized glass according to this embodiment ＩＣ is 1.2 MPa m １／２ More preferably, 1.3 MPa m １／２ More preferably, 1.3 to 2.0 MPa m １／２ Here, from the viewpoint of high strength, the fracture toughness value K ＩＣ is 1.2 MPa m １／２ More preferably, 1.3 MPa m １／２ More preferably, 1.4 MPa m １／２ More preferably, 1.5 MPa m １／２ The upper limit is not particularly limited, but is, for example, 2.0 MPa m １／２ The fracture toughness value K ＩＣ is the type of crystal that constitutes the crystalline phase, Li ２ Si ２ O ５ The fracture toughness value K ＩＣ can be measured by the pre-crack introduction fracture test method (SEPB method: Single-Edge-Precracked-Beam method) specified in JIS R1607:2015.

[0083] The Young's modulus of the crystallized glass according to this embodiment is preferably 95 to 120 GPa. From the viewpoint of high strength, the Young's modulus is preferably 95 GPa or more, more preferably 100 GPa or more, and even more preferably 105 GPa or more. From the viewpoint of high strength, the higher the Young's modulus, the more preferable it is, and there are no particular restrictions on it, but it may be, for example, 120 GPa or less. The Young's modulus in this specification can be measured by an ultrasonic method.

[0084] The haze value of the crystallized glass according to this embodiment is preferably 0.03 to 0.29%, and may be 0.05 to 0.25%. From the viewpoint of visibility when the crystallized glass is used as a cover glass, particularly a three-dimensionally shaped cover glass, the haze value is preferably 0.29% or less, more preferably 0.25% or less, even more preferably 0.20% or less, even more preferably 0.18% or less, particularly preferably 0.15% or less, and particularly preferably 0.10% or less. The smaller the haze value, the better, but it is usually 0.03% or more, and may be 0.05% or more. The haze value can be adjusted by the crystal species, degree of crystallization, and glass composition. The haze value in this specification refers to the value measured using illuminant C in accordance with JIS K7136:2000, converted into a 0.6 mm thickness of the crystallized glass. Furthermore, when the actual thickness of the crystallized glass is not 0.6 mm, the haze value can be converted into a 0.6 mm thickness based on the measured value using the Lambert-Beer law. Furthermore, when the plate thickness t is greater than 0.6 mm, the plate thickness of the crystallized glass may be adjusted to 0.6 mm by polishing, etching, or the like, before measurement.

[0085] The average transmittance of the crystallized glass according to this embodiment for light with wavelengths of 380 to 780 nm, when converted to a thickness of 0.6 mm, is preferably 85% or more, and may be 85 to 95%. From the viewpoint of achieving higher transparency, the average transmittance is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. The upper limit of the average transmittance is not particularly limited; the higher the transmittance, the better; however, it is typically 95% or less, and may be 92% or less. In this specification, the average transmittance refers to the average linear transmittance of light with wavelengths of 380 to 780 nm. Furthermore, if the actual thickness of the crystallized glass is not 0.6 mm, the measured value can be converted to the transmittance converted to a thickness of 0.6 mm using the Lambert-Beer law. Furthermore, if the plate thickness t is greater than 0.6 mm, the plate thickness of the crystallized glass may be adjusted to 0.6 mm by polishing, etching, or the like, before measurement.

[0086] The crystallized glass according to this embodiment can also achieve good chemical resistance. Specifically, it is preferable that the glass has at least one of acid resistance and alkali resistance, and more preferably both resistances.

[0087] As an indicator of acid resistance, the change (increase difference) in the haze value (%) converted to a thickness of 0.6 mm after immersion in 0.1 mol% hydrochloric acid at 90 ° C for 20 hours is used as a judgment index. Compared to the haze value of crystallized glass, the haze value after immersion is usually higher than the haze value before immersion. Therefore, if the difference between the haze value after immersion and the haze value before immersion is 0.05% or less, the acid resistance can be determined to be good. The difference is preferably 0.05% or less, more preferably 0.04% or less, and even more preferably 0.03% or less. The smaller the difference, the better, and the lower limit is not particularly limited. For example, 0%, i.e., no change in the haze value before and after immersion, is particularly preferred, but a difference of 0.01% or more is also acceptable.

[0088] As an indicator of alkali resistance, the change (increase difference) in the haze value (%) converted to a thickness of 0.6 mm after immersion in a 0.1 mol% aqueous sodium hydroxide solution at 90°C for 20 hours is used as a judgment index. Compared to the haze value of crystallized glass, the haze value after immersion is usually higher than the haze value before immersion. Therefore, if the difference between the haze value after immersion and the haze value before immersion is 3% or less, the alkali resistance can be determined to be good. The difference is preferably 3% or less, more preferably 2.8% or less, and even more preferably 2.5% or less. The smaller the difference, the better, and there is no particular lower limit. For example, 0%, i.e., no change in the haze value before and after immersion, is particularly preferred, but a difference of 2% or more is acceptable.

[0089] <Chemically strengthened glass> The crystallized glass according to this embodiment may be chemically strengthened glass having a compressive stress layer formed by ion exchange on the surface layer. The matrix composition of the chemically strengthened glass is the composition of the crystallized glass before chemical strengthening treatment (ion exchange treatment), and except in cases where extreme ion exchange treatment has been performed, the composition of the chemically strengthened glass deeper than the compressive stress layer depth (DOL) can be considered to be the same as the matrix composition of the chemically strengthened glass. In other words, the composition of the center of the plate thickness of the chemically strengthened glass coincides with the matrix composition of the chemically strengthened glass and can be considered to be the same as the composition of the crystallized glass.

[0090] The chemically strengthened glass according to this embodiment is preferably a chemically strengthened glass in which Li ions in the surface layer of the crystallized glass are ion-exchanged with Na ions. ２ The content of O is determined based on the composition of the glass-ceramics before chemical strengthening, i.e., the Na content in the base composition of the chemically strengthened glass. ２ The content of Na is preferably higher than that of O, and the difference is more preferably 1 mol % or more, further preferably 5 mol % or more, and even more preferably 10 mol % or more. ２ The upper limit of the difference in the O content is not particularly limited, but is, for example, 30 mol % or less.

[0091] From the viewpoint of improving the falling ball strength and the drop strength, the chemically strengthened glass according to this embodiment preferably has a compressive stress layer in which Na ions are ion-exchanged with K ions in addition to the ion exchange of Li ions and Na ions. In this case, a surface compressive stress is imparted to a portion close to the surface of the glass due to the ion exchange of Na ions with K ions, and a deep compressive stress is imparted to a portion deeper than that due to the ion exchange of Li ions with Na ions.

[0092] The chemically strengthened glass according to this embodiment does not show any significant changes in the overall composition and crystallinity of the glass, as well as its characteristics and physical properties (other than strength), compared to the crystallized glass before chemical strengthening, and can be considered to be the same. However, the peak position in the X-ray diffraction (XRD) pattern of the surface of the crystallized glass shifts from before the chemical strengthening treatment. In addition, the surface layer of the chemically strengthened glass may have different composition, crystal structure, and crystallinity.

[0093] Regarding the above XRD pattern, in the X-ray diffraction pattern of the surface using Cu-Kα radiation, Li ２ Si ２ O ５ The peak position derived from the crystal may shift before and after ion exchange, or may shift to a lower angle. The peak shift means that the ions in the crystal are also exchanged. The XRD measurement is performed on the surface of the crystallized glass before and after chemical strengthening treatment using CuKα radiation in the 2θ range of 10° to 80°. Specifically, the Li of the chemically strengthened glass ２ Si ２ O ５ Of the peaks derived from the crystals, the peak shift from the peak before ion exchange is preferably 0.02° or more, more preferably 0.02 to 0.10°. Here, the peak shift is preferably 0.02° or more, more preferably 0.03° or more. Furthermore, from the viewpoint of maintaining the crystal structure, the peak shift is preferably 0.10° or less, more preferably 0.08° or less.

[0094] The chemically strengthened glass according to this embodiment may have different physical properties related to strength compared to the crystallized glass before chemical strengthening. Examples of the physical properties include compressive stress (CS), compressive stress layer depth (DOL), internal tensile stress (CT), ST limit, fracture toughness, Young's modulus, Vickers hardness, etc. On the other hand, no significant changes are observed in physical properties other than strength, such as haze value, average transmittance, and average thermal expansion coefficient, before and after chemical strengthening.

[0095] The compressive stress value (CS ０ From the viewpoint of preventing cracks due to deformation such as bending, the compressive stress value (CS) at the outermost surface is preferably 300 MPa or more, more preferably 500 MPa or more, and even more preferably 600 MPa or more. ０ The upper limit of the compressive stress value (CS) at the outermost surface is not particularly limited, but is, for example, 1400 MPa or less. ０ ) can be adjusted, for example, by the Na concentration in the molten salt used in the chemical strengthening treatment, the chemical strengthening treatment conditions, the Li concentration in the glass composition, etc.

[0096] In this specification, the compressive stress value (CS) can be measured by slicing a cross section of chemically strengthened glass and analyzing the slicing sample with a birefringence imaging system. An example of a birefringence imaging system is the Abrio-IM birefringence imaging system manufactured by Tokyo Instruments Inc. The compressive stress value can also be measured using scattered light photoelasticity. In this method, light is incident on the surface of the chemically strengthened glass, and the polarization of the scattered light is analyzed to measure CS. An example of a stress measuring instrument using scattered light photoelasticity is the scattered light photoelasticity stress meter SLP-2000 manufactured by Orihara Seisakusho.

[0097] An optical waveguide surface stress meter is a measuring device used to measure the compressive stress on the outermost surface of chemically strengthened glass. Optical waveguide surface stress meters can accurately measure the stress of glass in a short time. However, in principle, optical waveguide surface stress meters can only measure stress when the refractive index decreases from the surface of the sample toward the inside. Here, if the outermost layer of chemically strengthened glass is a layer obtained by replacing sodium ions inside the glass with potassium ions from the outside, the refractive index decreases from the surface of the sample toward the inside, so stress can be measured with an optical waveguide surface stress meter. When measuring compressive stress using an optical waveguide surface stress meter, measurements are performed under the following conditions, for example. - Measuring device: FSM-6000 (manufactured by Orihara Manufacturing Co., Ltd.) - Measurement wavelength: 365 nm

[0098] The compressive stress layer depth (DOL) of the chemically strengthened glass according to this embodiment is preferably 50 μm or more, more preferably 60 μm or more, and even more preferably 70 μm or more, from the viewpoint of preventing cracks when scratches occur on the surface of the chemically strengthened glass. The upper limit of the compressive stress layer depth is not particularly limited, but is, for example, 200 μm or less. The value of the compressive stress layer depth can be adjusted, for example, by the molten salt, temperature, time, etc. used in the chemical strengthening treatment. In this specification, the compressive stress layer depth (DOL) is the depth at which the compressive stress value (CS) becomes zero.

[0099] The compressive stress layer depth (DOL) of the chemically strengthened glass according to this embodiment is preferably {t × 0.13} μm or more relative to the plate thickness t (μm), and more preferably {t × 0.13 + 10} μm or more and {t × 0.13 + 70} μm or less. Here, from the viewpoint of preventing cracks when scratches occur on the surface of the chemically strengthened glass, the compressive stress layer depth DOL is preferably {t × 0.13} μm or more, more preferably {t × 0.13 + 10} μm or more, even more preferably {t × 0.13 + 20} μm or more, and even more preferably {t × 0.13 + 25} μm or more. Further, from the viewpoint of improving the productivity of the strengthening process, the compressive stress layer depth DOL is preferably {t × 0.13 + 70} μm or less, more preferably {t × 0.13 + 50} μm or less, and even more preferably {t × 0.13 + 40} μm or less.

[0100] The chemically strengthened glass according to this embodiment has a compressive stress value (CS ０) is 300 MPa or more, and the compressive stress layer depth (DOL) is 50 μm or more and the plate thickness t (μm) is {t × 0.13} μm or more. It is more preferable that it satisfies at least one of these.

[0101] The Vickers hardness of the chemically strengthened glass according to this embodiment is preferably 680 GPa or more, more preferably 720 GPa or more, and even more preferably 750 GPa or more from the viewpoint of scratch resistance. The higher the Vickers hardness, the more preferable it is, but it is usually 1200 GPa or less. In this specification, the Vickers hardness refers to the Vickers hardness (HV0.1) defined in JIS R1610:2003.

[0102] <<Uses>> The crystallized glass according to this embodiment is useful as a cover glass for electronic devices such as mobile devices such as mobile phones and smartphones. It is also useful as a cover glass for non-portable electronic devices such as televisions, personal computers, and touch panels, as well as elevator walls and wall surfaces (full-surface displays) of buildings such as houses and buildings. It is 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. Furthermore, the crystallized glass according to this embodiment becomes extremely useful for each of the above applications by undergoing a chemical strengthening treatment.

[0103] <<Method for manufacturing crystallized glass>> The method for manufacturing crystallized glass according to this embodiment is not particularly limited, but includes, for example, the following steps 1 and 2. Furthermore, when crystallized glass is converted into chemically strengthened glass by chemical strengthening treatment, it is preferable to further include the following step 3 in addition to steps 1 and 2.

[0104] Step 1: A step of producing amorphous glass. Step 2: A step of crystallizing the amorphous glass obtained in step 1 to obtain crystallized glass. Step 3: A step of chemically strengthening the crystallized glass obtained in step 2 to obtain chemically strengthened glass.

[0105] Each step will be described below.

[0106] <Step 1> Step 1 is a step of producing amorphous glass, and a conventionally known method can be used as the specific method. That is, when obtaining amorphous glass, for example, glass raw materials are blended to obtain a desired composition and heated and melted in a glass melting furnace. The molten glass is then homogenized by bubbling, stirring, adding a fining agent, etc., formed into a desired shape by a known forming method, and slowly cooled. Alternatively, the molten glass may be formed into a block, slowly cooled, and then cut and processed into a desired shape. Examples of glass forming methods include the float method, the press method, the fusion method, and the downdraw method. Examples of slowly cooling methods include a method of cooling to room temperature at a rate of 0.1 to 2°C / min. The slowly cooling may be performed by holding the glass at a specific temperature for a specific time and then cooling to room temperature. Specifically, for example, the glass may be held at 420 to 550°C for 10 to 180 minutes and then cooled to room temperature at a rate of 0.1 to 2°C / min.

[0107] <Step 2> Step 2 is a step of obtaining crystallized glass by crystallizing the amorphous glass obtained in step 1. This results in crystallized glass having a crystalline phase and a desired composition.

[0108] The heat treatment for crystallization is not particularly limited as long as it produces the desired crystals, but may be, for example, a two-stage heat treatment in which the temperature is raised from room temperature to a first treatment temperature and maintained for a certain period of time, and then maintained at a second treatment temperature higher than the first treatment temperature for a certain period of time. After the two-stage heat treatment, a three-stage heat treatment may be performed in which the temperature is maintained at a third treatment temperature for a certain period of time. Alternatively, a one-stage heat treatment in which the temperature is maintained at a specific treatment temperature and then cooled to room temperature may be performed.

[0109] In the case of a two-stage heat treatment, the first treatment temperature is preferably in a temperature range where the crystal nucleation rate is high for the glass composition, and the second treatment temperature is preferably in a temperature range where the crystal growth rate is high for the glass composition.

[0110] In the case of a three-stage heat treatment, it is preferable that the first and second treatment temperatures are temperatures at which the crystal nucleation rate increases, and the third treatment temperature is a temperature at which the crystal growth rate increases. Alternatively, the first treatment temperature may be a temperature at which the crystal nucleation rate increases, and the second and third treatment temperatures may be temperatures at which the crystal growth rate increases.

[0111] In the two-stage heat treatment and the three-stage heat treatment, the holding time at the first treatment temperature is preferably long enough to generate a sufficient number of crystal nuclei. The generation of a large number of crystal nuclei reduces the size of each crystal, resulting in a highly transparent crystallized glass.

[0112] More specifically, in the case of a two-stage treatment, for example, the first treatment temperature is held at 500°C to 700°C for 1 hour to 6 hours, and then the second treatment temperature is held at 600°C to 800°C for 1 hour to 6 hours.

[0113] More specifically, in the case of a three-stage treatment, for example, after holding at a first treatment temperature of 450°C to 600°C for 1 hour to 6 hours, for example, at a second treatment temperature of 500°C to 650°C for 1 hour to 6 hours, and further, for example, at a third treatment temperature of 600°C to 800°C for 1 hour to 6 hours.

[0114] More specifically, in the case of a one-stage treatment, the temperature may be maintained at 500° C. to 800° C. for 1 hour to 6 hours.

[0115] The crystallized glass obtained in step 2 may be ground and polished as necessary. When the crystallized glass obtained is cut to a predetermined shape and size or chamfered, it is preferable to perform the cutting or chamfering before performing the chemical strengthening treatment in the next step 3. This allows a compressive stress layer to be formed on the cut surface or the chamfered surface by the subsequent chemical strengthening treatment.

[0116] <Step 3> Step 3 is a step of obtaining chemically strengthened glass by performing a chemical strengthening treatment on the crystallized glass obtained in step 2. The chemical strengthening treatment is a treatment in which the glass is brought into contact with a metal salt (e.g., potassium nitrate) containing a metal ion with a large ionic radius (typically, Na ion or K ion) by, for example, immersing the glass in a melt of the metal salt, thereby replacing the metal ion with a small ionic radius (typically, Li ion or Na ion) with a metal ion with a large ionic radius (typically, Na ion or K ion for Li ion, and K ion for Na ion).

[0117] To increase the speed of chemical strengthening, it is preferable to use "Li-Na exchange," which exchanges Li ions in the glass with Na ions. Here, the crystallized glass in this embodiment contains a crystalline phase, but a compressive stress layer is formed not only in the amorphous phase but also when Li constituting the crystalline phase is converted to Na.

[0118] In order to form a larger compressive stress by ion exchange, it is preferable to use "Na-K exchange" in which Na ions in the glass are exchanged with K ions.

[0119] Examples of molten salts for chemical strengthening include nitrates, sulfates, carbonates, and chlorides. Examples of nitrates include lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, and silver nitrate. Examples of sulfates include lithium sulfate, sodium sulfate, potassium sulfate, cesium sulfate, and silver sulfate. Examples of carbonates include lithium carbonate, sodium carbonate, and potassium carbonate. Examples of chlorides include lithium chloride, sodium chloride, potassium chloride, cesium chloride, and silver chloride. These molten salts may be used alone or in combination.

[0120] When both the Li—Na exchange and the Na—K exchange are carried out, for example, a mixed molten salt of lithium nitrate, sodium nitrate, and potassium nitrate may be used. In this case, the mixing ratio of lithium nitrate, sodium nitrate, and potassium nitrate is not particularly limited, but for example, the lithium nitrate is preferably 0.002 to 0.5 parts by mass, the sodium nitrate is preferably 20 to 70 parts by mass, and the potassium nitrate is preferably 30 to 80 parts by mass, per 100 parts by mass of the total of lithium nitrate, sodium nitrate, and potassium nitrate.

[0121] The conditions for the chemical strengthening treatment, such as time and temperature, can be selected taking into consideration the glass composition, the type of molten salt, etc. For example, the crystallized glass obtained in step 2 can be chemically strengthened at preferably 500°C or less for preferably 20 hours or less. Alternatively, two or more stages of chemical strengthening treatment may be performed.

[0122] The present invention will be described below with reference to test examples, but the present invention is not limited thereto. Examples 1 to 12 are working examples, and Examples 13 to 16 are comparative examples.

[0123] Examples 1 to 16 Glass raw materials were mixed to obtain the glass compositions shown in "Ceramics Composition (%)" in Table 1 or Table 2, expressed 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 1550°C, melted for about 5 hours, degassed, and homogenized. The resulting molten glass was poured into a mold, held at 470°C for 1 hour, and then cooled to room temperature at a rate of 0.5°C / min to obtain a glass block. Note that blanks in the glass compositions in Tables 1 and 2 indicate that no additives were added. Table 1 also lists the glass compositions containing {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is referred to as "Si / LAS" and ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O]) × 100} is referred to as "Al / LAS" and {[Li２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is also shown as "Li / LAS."

[0124] The obtained glass blocks were each processed into plates measuring 50 mm x 50 mm x 0.6 mm and subjected to a two-stage or three-stage crystallization treatment. Specifically, the first and second treatments, or the first, second and second treatments, were performed at the temperatures and holding times listed under "Crystallization Conditions" in Tables 1 and 2. The blocks were then cooled to room temperature to obtain crystallized glass. Note that the "-" mark in the "Crystallization Conditions" section of Tables 1 and 2 indicates that the third treatment was not performed. None of the obtained crystallized glass exhibited any cloudiness due to crystal enlargement, etc., and it was confirmed that the desired transparency was achieved.

[0125] <Evaluation> <Composition: Glass-ceramics, amorphous phase> Composition analysis of the obtained glass-ceramics revealed no significant change from the glass composition before crystallization, and confirmed that it was the same as the glass composition shown in Table 1 or Table 2. Therefore, in Tables 1 and 2, the composition is shown as "glass-ceramics composition (%)." The composition of the amorphous phase of the glass-ceramics was determined from the composition of the glass-ceramics, the degree of crystallization, and the precipitated crystalline phase and its content ratio. The results are shown in "Amorphous phase composition (%)" in Table 1 or Table 2.

[0126] <Crystalline Phase> The obtained crystallized glass was subjected to powder X-ray diffraction measurement under the following conditions, and the precipitated crystals, their content ratio, and average crystallite size of the crystals were determined by Rietveld analysis. The results are shown in "Crystalline Phase" in Table 1 or Table 2. "LD Crystallinity (wt%)" refers to the percentage of Li in the crystallized glass. ２ Si ２ O ５ The content of other crystals is the percentage of Li in the crystallized glass. ２ Si ２ O ５ The total content of crystals other than crystals is shown in parentheses. ２ Si ２ O ５The type of crystals other than crystals is also specified. The sum of the value of "LD crystallinity (wt%)" and the value of "other crystals (wt%)" is the crystallinity (mass%) of the crystallized glass. Also, "LD crystallinity (vol%)" refers to the amount of Li in the crystallized glass. ２ Si ２ O ５ The crystal content is expressed as a volume fraction, and blank spaces mean that the data has not been calculated. The blank spaces for "average crystallite size (nm)" in Tables 1 and 2 mean that the data has not been analyzed. Measuring device: SmartLab manufactured by Rigaku Corporation X-ray used: Cu-Kα ray Measurement range: 2θ = 10° to 80° Speed: 10° / min Step: 0.02°

[0127] Strength: Fracture toughness value K ＩＣ > Fracture toughness value K of the obtained crystallized glass ＩＣ The strength was measured using a strength testing machine (Shimadzu Corporation, Autograph AGS-X) according to the pre-crack introduction fracture test method (SEPB method: Single-Edge-Precracked-Beam method) specified in JIS R1607:2015. The results are shown in Tables 1 and 2 under "K ＩＣ (MPa m １／２ ) shown below.

[0128] <Young's modulus> The Young's modulus of the obtained crystallized glass was measured by an ultrasonic method using an ultrasonic thickness gauge (manufactured by Olympus Corporation, product name 38DL). The results are shown in Tables 1 and 2 under "Young's modulus (GPa)", and blanks in the tables mean that no measurement was performed.

[0129] <Haze Value> The haze value (converted to a thickness of 0.6 mm) of the obtained crystallized glass was measured using a haze meter (HZ-V3 manufactured by Suga Test Instruments Co., Ltd.) under Illuminant C in accordance with JIS K 3761: 2000. The results are shown in "Haze (%)" in Tables 1 and 2, with blanks in the tables meaning that no measurement was performed.

[0130] <Average Transmittance> The average transmittance of the obtained crystallized glass (converted to a thickness of 0.6 mm) was measured using a spectrophotometer (product name: U-4100) manufactured by Hitachi High-Tech Corporation. Specifically, the transmittance of light with wavelengths of 380 to 780 nm was measured at 1 nm intervals, and the average value of these was taken as the average transmittance. The results are shown in "Average Transmittance (%)" in Tables 1 and 2, with blanks in the tables indicating that no measurement was performed.

[0131] <Chemical resistance; acid resistance> The obtained crystallized glass was immersed in 0.1 mol% hydrochloric acid at 90°C for 20 hours, and then the haze value was measured. Specifically, the measurement was performed under the same conditions as those described in the above <Haze value>. Then, the difference in the increase from the haze value (%) before immersion, which was obtained in the above <Haze value>, was calculated. The results are shown in "Acid resistance; Haze difference (%)" in Table 1 and Table 2, and blanks in the tables indicate that no measurement was performed.

[0132] <Chemical Resistance; Alkali Resistance> The obtained crystallized glass was immersed in a 0.1 mol% aqueous sodium hydroxide solution at 90°C for 20 hours, and then the haze value was measured. Specifically, the measurement was performed under the same conditions as those described in the above <Haze Value>. Then, the difference in the increase from the haze value (%) before immersion, which was obtained in the above <Haze Value>, was calculated. The results are shown in "Alkali Resistance; Haze Difference (%)" in Tables 1 and 2, and blanks in the tables indicate that no measurement was performed.

[0133] <Chemically strengthened glass> The crystallized glasses obtained in Examples 1 and 3 were immersed in a molten salt mixture of potassium nitrate, sodium nitrate, and lithium nitrate = 60:39.97:0.03 (mass ratio) at 450 ° C. for 4 hours, washed, and dried to obtain chemically strengthened glass. The stress profile in the depth direction of the obtained chemically strengthened glass was measured using a measuring instrument SLP-2000 manufactured by Orihara Seisakusho Co., Ltd. Based on the stress profile, the compressive stress value CS of the outermost surface of the glass was measured. ０ The compressive stress (MPa) and compressive stress layer depth DOL (μm) were measured. The results are shown in Tables 1 and 2 under "CS ０ The values ​​are shown in "(MPa)" and "DOL (μm)", respectively. Note that, since Example 2 and Examples 4 to 16 were not subjected to chemical strengthening treatment, Tables 1 and 2 are left blank.

[0134]

[0135]

[0136] From the above results, it can be seen that the crystallized glass according to this embodiment satisfies a specific composition range, thereby ２ Si ２ O ５ As a result of being able to selectively precipitate crystals to a content ratio of 50 mass% or more, good transparency and high fracture toughness value K Ｉｃ Furthermore, the crystallized glass according to this embodiment contains SnO ２ It was found that the inclusion of [beta] provides excellent chemical resistance, such as acid resistance and alkali resistance, and maintains transparency. Furthermore, the crystallized glass according to this embodiment also achieves improved strength due to the formation of a compressive stress layer by chemical strengthening treatment.

[0137] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese patent applications filed on June 7, 2024 (Patent Application No. 2024-092882), January 14, 2025 (Patent Application No. 2025-004714), February 17, 2025 (Patent Application No. 2025-023653), and March 31, 2025 (Patent Application No. 2025-058530), the contents of which are incorporated herein by reference.

Claims

A crystallized glass having a crystalline phase and an amorphous phase, The composition of the crystallized glass is expressed in mole percentage based on oxides as follows: Yes ２ 55-70%, Li ２ O 15~30%、 Al ２ O ３ 1.00-4.50 P ２ O ５ 0.5 to 5.0%, ZrO ２ 0.5 to 4.4%, and SnO ２ greater than 0%, and SiO ２ , Al ２ O ３ , and Li ２ Using the content ratio of O expressed as mole percentage, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 68.5 to 76.0%, {[Al ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 1.0 to 5.0%, and {[Li ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 21.0 to 29.0%, The crystalline phase is Li ２ Si ２ O ５ Contains crystals, The Li in the crystallized glass ２ Si ２ O ５ The crystal content is 50 to 85 mass %. 　 A crystallized glass having a crystalline phase and an amorphous phase, The composition of the crystallized glass is SiO 2 expressed in mole percentage based on oxides. ２ , Al ２ O ３ , and Li ２ Using the content ratio of O, {[SiO ２ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 68.5 to 76.0%, {[Al ２ O ３ ] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 1.0 to 5.0%, and {[Li ２ O] / ([SiO ２ ]+[Al ２ O ３ ]+[Li ２ O] × 100} is 21.0 to 29.0%, The crystalline phase is Li ２ Si ２ O ５ Contains crystals, The Li in the crystallized glass ２ Si ２ O ５ The content of crystals is 50 to 85 mass %; The composition of the amorphous phase is expressed in mole percentage on an oxide basis as follows: Yes ２ 50-72%, Li ２ O 0.1~15%、 Al ２ O ３ 3~15%、 P ２ O ５ 1~10%, ZrO ２ 1~15%、 SnO ２ 0.01~5%、 Na ２ O 1-18%, and K ２ O 0 to 7%. 　 The composition of the crystallized glass is expressed in mole percentage based on oxides as follows: Yes ２ 55-70%, Li ２ O 15~30%、 Al ２ O ３ 1.00-4.50 P ２ O ５ 0.5 to 5.0%, ZrO ２ 0.5 to 4.4%, and SnO ２ The crystallized glass according to claim 2, wherein the crystallized glass satisfies the above formula (1). 　 The composition of the crystallized glass is expressed in mole percentage based on oxides as follows: Na ２ O 0.1 to 5%, and K ２ The crystallized glass according to claim 1 or 3, further comprising: O 0 to 3%. The Li in the crystallized glass ２ Si ２ O ５ 3. The crystallized glass according to claim 1, wherein the content of crystals other than crystals is 10% by mass or less. 　 The composition of the crystallized glass is SiO 2 expressed in mole percentage based on oxides. ２ , Al ２ O ３ , and Li ２ 4. The crystallized glass according to claim 1, wherein the total content of O is 90% or more. 　 Fracture toughness value K ＩＣ is 1.3 MPa m １／２ The crystallized glass according to claim 1 or 2, wherein 　 3. The crystallized glass according to claim 1, having a Young's modulus of 95 to 120 GPa.

3. The crystallized glass according to claim 1, wherein the haze value when converted into a thickness of 0.6 mm is 0.03 to 0.29%.

3. The crystallized glass according to claim 1, wherein the average transmittance of light having a wavelength of 380 to 780 nm is 85% or more when converted into a glass having a thickness of 0.6 mm.

3. The crystallized glass according to claim 1, wherein the average crystallite size of the crystals constituting the crystalline phase is 20 to 200 nm.

3. The crystallized glass according to claim 1, wherein the difference in the increase in haze value (%) converted to a thickness of 0.6 mm after immersion in 0.1 mol% hydrochloric acid at 90°C for 20 hours is 0.05% or less.

3. The crystallized glass according to claim 1, wherein the difference in the increase in haze value (%) converted to a thickness of 0.6 mm after immersion in a 0.1 mol% aqueous sodium hydroxide solution at 90°C for 20 hours is 3% or less.

3. The crystallized glass according to claim 1, which has a compressive stress layer formed on its surface by ion exchange. 　 Compressive stress value CS on the outermost surface ０ The crystallized glass according to claim 14, wherein the strain is 300 MPa or more. 　 The crystallized glass according to claim 14, wherein the compressive stress layer depth DOL is 50 μm or more.

15. The crystallized glass according to claim 14, wherein the compressive stress layer depth DOL is {t×0.13} μm or more, where t (μm) is the thickness of the glass.

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