Chemically strengthened glass, method for manufacturing chemically strengthened glass

Abstract

We provide chemically strengthened glass with excellent resistance to high temperatures and high humidity. [Solution] A chemically strengthened glass in which the average hydrogen atom concentration at a depth of 0.75 to 1.25 μm from the surface is 2.000 × 10 20 atoms / cm 3 That concludes our explanation of chemically strengthened glass.

Description

[Technical Field]

[0001] This invention relates to chemically strengthened glass. The present invention also relates to a method for manufacturing chemically strengthened glass. [Background technology]

[0002] In recent years, cover glass has been used to protect and enhance the aesthetics of display devices in mobile phones, smartphones, and tablet devices. Cover glass used in these applications requires excellent strength to prevent damage from impacts and other factors. Furthermore, cover glass like the one described above is sometimes used to protect solar cell modules and other components.

[0003] Conventionally, a method has been known to increase the surface strength of glass by chemically strengthening it through immersion in potassium nitrate molten salt or the like. For example, Patent Document 1 discloses that the surface strength of a glass plate can be improved by chemically strengthening it by immersing it in a potassium nitrate molten salt. More specifically, it discloses that the strength of a glass plate can be improved by chemically strengthening a glass containing Li with a molten salt containing Na and then a molten salt containing K in sequence. It also states that the mechanism by which the strength of the glass plate is strengthened by such chemical treatment is due to the compressive stress generated by the exchange of alkali metals. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2017 / 170053 [Overview of the project] [Problems that the invention aims to solve]

[0005] Chemically strengthened glass can also be used in high-temperature and high-humidity environments. When the present inventors examined the chemically strengthened glass described in Patent Document 1, they found that it sometimes had poor resistance to high temperature and high humidity, and there was a need for improvement.

[0006] This invention has been made in view of the above problems, and aims to provide chemically strengthened glass that has excellent resistance to high temperature and high humidity. Furthermore, the present invention also aims to provide a method for manufacturing chemically strengthened glass. [Means for solving the problem]

[0007] As a result of diligent research into the above-mentioned problems, the inventors of this invention discovered that high temperature and high humidity resistance can be improved by setting the hydrogen concentration on the surface within a predetermined range, leading to the completion of the present invention.

[0008] In other words, the inventors found that the above problem could be solved by the following configuration. [1] Chemically strengthened glass, The average hydrogen atom concentration at a depth of 0.75 to 1.25 μm from the surface is 2.000 × 10⁻¹⁶ 20 atoms / cm 3 That concludes our explanation of chemically strengthened glass. [2] The chemically strengthened glass according to [1], wherein the ratio of the hydrogen atom concentration at a depth of 1.00 μm from the surface to the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface is 1.490 or greater. [3] The chemically strengthened glass according to [1] or [2], wherein the ratio of the hydrogen atom concentration at a depth of 1.50 μm from the surface to the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface is 1.250 or more. [4] The absolute value of the slope of hydrogen atom concentration with respect to depth, calculated from the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface and the hydrogen atom concentration at a depth of 0.50 μm from the surface, is 0.600 × 10 20 atoms / cm 3 Chemically strengthened glass described in any one of [1] to [3], having a thickness of μm or more. 〔5〕 The value obtained by subtracting the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface from the hydrogen atom concentration at a depth of 0.50 μm from the surface is 1.800×10 20 atoms / cm 3 or more, the chemically strengthened glass according to any one of 〔1〕 to 〔4〕. 〔6〕 The ratio of the integral approximation value of the hydrogen atom concentration at a depth of 0.00 to 1.00 μm from the surface to the average hydrogen atom concentration at a depth of 0.75 to 1.25 μm from the surface is 15.000×10 -5 ·cm or less, the chemically strengthened glass according to any one of 〔1〕 to 〔5〕. 〔7〕 The chemically strengthened glass according to any one of 〔1〕 to 〔6〕, which is crystallized glass. 〔8〕 The chemically strengthened glass according to 〔7〕, containing one or more crystals selected from the group consisting of lithium silicate crystals, lithium aluminosilicate crystals, and lithium phosphate crystals. 〔9〕 The chemically strengthened glass according to 〔7〕 or 〔8〕, having a crystallization rate of 10 to 70%. 〔10〕 The composition of the above chemically strengthened glass is expressed in mole percentage based on oxides, SiO2 is 40.00 to 75.00%, Al2O3 is 2.00 to 20.00%, Li2O is 9.00 to 40.00%, Na2O is 1.00 to 8.00%, K2O is 0.00 to 2.00%, the chemically strengthened glass according to any one of 〔1〕 to 〔9〕. 〔11〕 After conducting a high-temperature and high-humidity resistance test of standing still for 240 hours in an environment of a temperature of 85 °C and a relative humidity of 85%, the haze is 20 times or less with respect to the haze before the high-temperature and high-humidity resistance test, the chemically strengthened glass according to any one of〔1〕 to 〔10〕. 〔12〕 The chemically strengthened glass according to any one of 〔1〕 to 〔11〕, having a plate thickness of 2.0 mm or less. 〔13〕 The fracture toughness value K IC is 0.82 MPa·m 1 / 2 or more, the chemically strengthened glass according to any one of 〔1〕 to 〔12〕.

[14] A chemically strengthened glass as described in any one of [1] to

[13] , having a Young's modulus of 84 GPa or higher.

[15] A method for producing chemically strengthened glass, comprising performing a chemical strengthening treatment in which chemically strengthened glass is brought into contact with a molten salt one or more times, The composition of the above chemically strengthened glass is expressed as a mole percentage based on oxides, SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% Li2O at 9.00-40.00%, Na2O at 1.00-5.00%, It contains 0.00 to 1.40% K2O. A method for manufacturing chemically strengthened glass, wherein the molten salt used in at least one of the above chemical strengthening treatments satisfies the following requirements 1 and 2. Requirement 1: The above molten salt contains silicic acid. Requirement 2: When the above molten salt is solidified and dissolved in pure water to obtain a 9% by mass aqueous solution, the pH of the aqueous solution must be 6.0 or less.

[16] A method for producing chemically strengthened glass as described in

[15] , wherein the above chemical strengthening treatment is performed two or more times.

[17] A method for manufacturing chemically strengthened glass as described in

[15] , wherein the above chemical strengthening treatment is performed three or more times.

[18] A method for producing chemically strengthened glass according to

[15] or

[16] , wherein the above chemical strengthening treatment is performed twice, and the molten salt used in the first chemical strengthening treatment satisfies requirement 1 and requirement 2.

[19] A method for manufacturing chemically strengthened glass according to any one of

[15] ,

[16] , and

[18] , wherein the above chemical strengthening treatment is performed twice, and the molten salt used in the first chemical strengthening treatment and the second chemical strengthening treatment satisfies requirement 1 and requirement 2.

[20] A method for manufacturing chemically strengthened glass according to any one of

[15] to

[17] , wherein the above chemical strengthening treatment is performed three times, and the molten salt used in the first and second chemical strengthening treatments satisfies requirement 1 and requirement 2.

[21] A method for manufacturing chemically strengthened glass according to any one of

[15] to

[17] and

[20] , wherein the above chemical strengthening treatment is performed three times, and the molten salt used in the first, second, and third chemical strengthening treatments satisfies requirement 1 and requirement 2.

[22] A method for producing chemically strengthened glass according to any one of

[15] to

[21] , wherein the ratio of the content of LiNO3 in the molten salt used in the first chemical strengthening treatment to the content of Li2O in the chemically strengthened glass is 75 mol% or less.

[23] A method for producing chemically strengthened glass according to any one of

[15] to

[22] , wherein the molten salt satisfying requirement 1 above further contains sodium metasilicate. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide chemically strengthened glass with excellent resistance to high temperatures and high humidity. Furthermore, the present invention provides a method for manufacturing chemically strengthened glass. [Brief explanation of the drawing]

[0010] [Figure 1] This is an explanatory diagram of the sample used for measuring the fracture toughness value KIC using the DCDC method. [Figure 2] This figure shows the K1-v curve, which illustrates the relationship between the stress intensity factor K1 (unit: MPa·m1 / 2) and the crack propagation rate v (unit: m / s), used in measuring the fracture toughness value KIC by the DCDC method. [Modes for carrying out the invention]

[0011] The chemically strengthened glass of the present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified and implemented as desired without departing from the spirit of the invention.

[0012] In this specification, "chemically strengthened glass" refers to glass that has undergone chemical strengthening treatment. "Chemically strengthened glass" refers to glass that has not undergone chemical strengthening treatment.

[0013] In this specification, the glass composition of chemically strengthened glass is sometimes referred to as the mother glass composition of chemically strengthened glass. In chemically strengthened glass, a compressive stress layer is usually formed on the glass surface due to ion exchange, so the glass composition of the non-ion-exchanged portion is the same as the mother glass composition of chemically strengthened glass. In this specification, glass composition is expressed in mole percentages based on oxides, and mole% may be simply written as %. Furthermore, the "~" symbol indicating a numerical range is used to mean that the values ​​before and after it are included as the lower and upper limits, respectively.

[0014] In glass composition, "substantially absent" means that, excluding unavoidable impurities contained in the raw materials, etc., it means that the impurities are not intentionally included. Specifically, for components other than those listed in the glass composition, for example, less than 0.1 mol% is preferred, 0.08 mol% or less is more preferred, and 0.05 mol% or less is even more preferred.

[0015] In this specification, a "stress profile" is a pattern representing compressive stress values ​​with respect to the depth from the glass surface as a variable. Negative compressive stress values ​​indicate tensile stress. In this specification, the "stress profile" can be measured using a scattered light photoelastic stress meter.

[0016] The method using a scattered light photoelastic stress meter allows for stress measurement regardless of the refractive index distribution that occurs from the surface to the interior of chemically strengthened glass. An example of a scattered light photoelastic stress meter is the SLP2000 manufactured by Orihara Corporation.

[0017] In this specification, the compressive stress layer depth is defined as the depth to which the compressive stress value becomes zero.

[0018] In this specification, "fracture toughness value K" IC The stress intensity factor K1 (unit: MPa·m) is measured using the DCDC method [Reference: MY He, MR Turner and AG Evans, Acta Metall. Mater. 43 (1995) 3453.]. Specifically, using a sample with the shape shown in Figure 1 and a SHIMADZU Autograph AGS-X5KN, the stress intensity factor K1 (unit: MPa·m) is measured as shown in Figure 2. 1 / 2 The K1-v curve, which shows the relationship between stress and crack propagation rate v (unit: m / s), was measured, and the obtained data for Region III was regression and extrapolated using a linear equation. The stress intensity factor K1 of 0.1 m / s was used to determine the fracture toughness value K IC Let's assume that.

[0019] In this specification, "high temperature and high humidity resistance" means that chemically strengthened glass does not experience a significant increase in haze when left undisturbed for 240 hours in an environment of 85°C and 85% relative humidity. The specific evaluation method for high temperature and high humidity resistance is described later.

[0020] <Chemically strengthened glass> The chemically strengthened glass of the present invention has an average hydrogen atom concentration of 2.000 × 10¹⁶ at a depth of 0.75 to 1.25 μm from the surface. 20 atoms / cm 3 That's all. The mechanism by which the chemically strengthened glass of the present invention exhibits excellent resistance to high temperatures and high humidity is not entirely clear, but the inventors speculate as follows. Through our research, we have found that under high temperature and high humidity conditions, a reaction between carbon dioxide in the air, water in the environment, and alkaline components in the chemically strengthened glass may cause white precipitates to form on the surface of the chemically strengthened glass. In the chemically strengthened glass of the present invention, the hydrogen atom concentration near the surface is relatively high. When the hydrogen atom concentration is high near the surface, the ionic radius of the hydrogen atom is small, so it is thought that the interatomic distance between the atoms constituting the glass tends to be short near the surface of the glass. Consequently, even if moisture adheres to the surface of the chemically strengthened glass in a high-temperature, high-humidity environment, alkaline components are less likely to dissolve to the surface of the chemically strengthened glass, and as a result, it is thought that the haze will not increase easily. The chemically strengthened glass of the present invention will be described below.

[0021] [Hydrogen atom concentration] The parameters related to the hydrogen atom concentration in the chemically strengthened glass of the present invention are obtained by obtaining a hydrogen concentration profile using the following method and analyzing it using various methods. Secondary ion mass spectrometry (SIMS) is used to measure the hydrogen concentration profile of chemically strengthened glass. SIMS allows for analysis while simultaneously cutting the surface with ion irradiation, making it possible to measure the hydrogen concentration at a predetermined depth. In this invention, the hydrogen concentration profile is obtained in a standard sample with a known hydrogen concentration. 1 H - / 30 Si - The depth profile of the intensity ratio and the chemically strengthened glass being measured, 1 H - / 30 Si - It is determined by comparing it with the depth-direction profile of the intensity ratio. The following describes in detail how to obtain a hydrogen concentration profile.

[0022] Standard samples with known hydrogen concentrations are prepared by the following method. First, cut out a portion of the chemically strengthened glass to be measured. A region of 50 μm or more is removed from the surface of the cut chemically strengthened glass by polishing or chemical etching. This removal process is performed on both sides of the chemically strengthened glass. That is, the total thickness of the removed material on both sides is 100 μm or more. The chemically strengthened glass from which the above surface has been removed is used as the standard sample. The obtained standard samples were measured using infrared spectroscopy (IR), and the IR spectrum obtained was measured at 3550 cm⁻¹. -1 Absorbance height A of the nearby peak top 3550 and 4000cm -1 Absorbance height A 4000 (Baseline) is determined. Next, the plate thickness d (cm) of the standard sample is measured using a plate thickness measuring instrument such as a micrometer. Then, referring to reference A, the practical infrared absorption coefficient ε of H2O in glass is determined. pract Set (L / (mol·cm)) to 75 and use equation (II) to determine the hydrogen concentration of the standard sample (converted to H2O, mol / L). Hydrogen concentration of standard sample = (A 3550 -A 4000 ) / (ε pract ·d)···Formula (II) Reference A: S. lievski et al., Glastech. Ber. Glass Sci. Technol., 73 (2000) 39.

[0023] The chemically strengthened glass to be measured and a standard sample with a known hydrogen concentration obtained by the above method are simultaneously transported into the SIMS apparatus, and measurements are performed sequentially. 1 H - and 30 Si - Obtain the depth profile of the intensity. Then, 1 H - From the profile 30 Si - Remove the profile, 1 H - / 30 Si - Obtain the depth-direction profile of the intensity ratio. Next, the standard sample 1 H - / 30 Si - From the depth-direction profile of the intensity ratio, the average in the region from depth 1 μm to 2 μm 1 H - / 30 Si - The intensity ratio is calculated, and a calibration curve is created between this value and the hydrogen concentration, passing through the origin. That is, a calibration curve with one level of standard sample is obtained. Using the above calibration curve, the vertical axis of the profile of the chemically strengthened glass to be measured is... 1 H - / 30 Si - The intensity ratio is converted to hydrogen concentration. The hydrogen concentration profile of the chemically strengthened glass to be measured is obtained using the above procedure. The measurement conditions for SIMS and IR are as follows.

[0024] (SIMS measurement conditions) The measurement conditions for SIMS in this invention are as follows: Equipment: ULVAC-PHI ADEPT1010 Primary ion species: Cs + Primary ion acceleration voltage: 5kV Primary ion current: 500 nA Angle of incidence of primary ions: 60° relative to the normal to the sample surface. Primary ion raster size: 300 x 300 μm 2 Polarity of secondary ions: negative Secondary ion detection area: 60 × 60 μm 2 (4% of the primary ion's luster size) ESA Input Lens: 0 Use of neutralizing gun: Yes Furthermore, the sputtering rate due to primary ions is measured in advance, and the sputtering time is converted into depth. Specifically, the depth of the analytical crater is measured using a stylus-type surface profile analyzer (Veeco Dektak150), and the sputtering rate of primary ions is determined. In addition, 1 H -The optimal Field Axis Potential for detection may vary depending on the device; therefore, the operator should carefully set the value to ensure sufficient background noise reduction.

[0025] (IR measurement conditions) The measurement conditions for IR in this invention are as follows: Equipment: Thermo Fisher Scientific Nic-plan / Nicolet 6700 Resolution: 4cm -1 Total number of times: 16 Detector: TGS detector

[0026] By following the above procedure, a hydrogen concentration profile can be obtained in the depth direction from the outermost surface of the chemically strengthened glass. In the above hydrogen concentration profile, the horizontal axis is depth (unit: μm) and the vertical axis is hydrogen concentration (unit: atoms / cm³). 3 This is the profile of ). In this specification, the average hydrogen atom concentration at a depth of d1 to d2 μm from the surface is the arithmetic mean of the hydrogen concentrations at measurement points within the range of d1 to d2 μm from the surface. Furthermore, in this specification, the hydrogen atom concentration at a depth of d3 μm from the surface is the value obtained by linearly interpolating between the measurement point closest to d3 μm and the measurement point second closest to d3 μm. If there is a measurement point for hydrogen concentration at d3 μm, the hydrogen concentration at that measurement point shall be considered the hydrogen concentration at d3 μm.

[0027] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration at a depth of 0.25 to 0.75 μm from the surface (hereinafter referred to as "A") 0.5μm It is also called ). ) is 2.500 × 10 20 atoms / cm 3 The above is preferable, 3,000 × 10 20 atoms / cm 3 The above is more preferable, 4.000 × 10 20 atoms / cm 3The above is more preferable. A 0.5μm is 100,000×10 20 atoms / cm 3 or less in many cases, 50,000×10 20 atoms / cm 3 or less is preferable, 30,000×10 20 atoms / cm 3 or less is more preferable, 10,000×10 20 atoms / cm 3 or less is even more preferable.

[0028] In the chemically strengthened glass of the present invention, the average hydrogen atom concentration at a depth of 0.75 to 1.25 μm from the surface (hereinafter also referred to as "A" 1.0μm .) is 2,000×10 20 atoms / cm 3 or more, and A 1.0μm is preferably 2,500×10 20 atoms / cm 3 or more, more preferably 3,000×10 20 atoms / cm 3 or more. A 1.0μm is often times 50,ooo×10 20 atoms / cm 3 or less, preferably 30,000×10 20 atoms / cm 3 or less, more preferably 15,000×10 20 atoms / cm 3 or less, even more preferably 10,000×10 20 atoms / cm 3 or less is even more preferable.

[0029] Also, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface (hereinafter also referred to as "A" 2.75μm .) is preferably 0.400×10 20 atoms / cm 3 or more, more preferably 0.600×10 20 atoms / cm 3 or more, even more preferably 0.900×10 20 atoms / cm 3 or more. A 2.75μm is 30,000×1020 atoms / cm 3 The following is often the case: 20,000 × 10 20 atoms / cm 3 The following is preferable: 10,000 × 10 20 atoms / cm 3 The following is more preferable: 5,000 × 10 20 atoms / cm 3 The following are even more preferable.

[0030] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration at a depth of 0.05 μm from the surface (hereinafter referred to as "C") 0.05μm It is also called ). ) is 2.500 × 10 20 atoms / cm 3 The above is preferable, 3,000 × 10 20 atoms / cm 3 The above is more preferable, 4.000 × 10 20 atoms / cm 3 The above is even more preferable. C 0.05μm is 100,000 × 10 20 atoms / cm 3 The following is often the case: 50,000 × 10 20 atoms / cm 3 The following is preferable: 30,000 × 10 20 atoms / cm 3 The following is more preferable: 15,000 × 10 20 atoms / cm 3 The following are even more preferable.

[0031] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration at a depth of 0.50 μm from the surface (hereinafter referred to as "C") 0.5μm It is also called ). ) is 2.000 × 10 20 atoms / cm 3 The above is preferable, 2,500 × 10 20 atoms / cm 3 The above is more preferable, 3,000 × 10 20 atoms / cm 3 The above is even more preferable: 4,000 × 10 20 atoms / cm 3 The above is particularly preferable. C 0.5μm is 100,000 × 10 20atoms / cm 3 The following is often the case: 50,000 × 10 20 atoms / cm 3 The following is preferable: 30,000 × 10 20 atoms / cm 3 The following is more preferable: 15,000 × 10 20 atoms / cm 3 The following are even more preferable.

[0032] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration at a depth of 1.00 μm from the surface (hereinafter referred to as "C") 1.0μm It is also called ). ) is 2.000 × 10 20 atoms / cm 3 Preferably, 2.250 × 10 20 atoms / cm 3 The above is more preferable, 2,500 × 10 20 atoms / cm 3 The above is even more preferable. C 1.0μm is 100,000 × 10 20 atoms / cm 3 The following is often the case: 50,000 × 10 20 atoms / cm 3 The following is preferable: 30,000 × 10 20 atoms / cm 3 The following is more preferable: 10,000 × 10 20 atoms / cm 3 The following are even more preferable.

[0033] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration at a depth of 1.50 μm from the surface (hereinafter referred to as "C") 1.5μm It is also called ). ) is 1.650 × 10 20 atoms / cm 3 The above is preferable, 1,700 × 10 20 atoms / cm 3 The above is more preferable, 2,000 × 10 20 atoms / cm 3 The above is even more preferable. C 0.5μm is 50,000 × 10 20 atoms / cm 3 The following is often the case: 30,000 × 10 20 atoms / cm3 The following is preferable: 15,000 × 10 20 atoms / cm 3 The following are preferable.

[0034] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (A) at a depth of 2.50 to 3.00 μm from the surface. 2.75μm The hydrogen atom concentration (C) at a depth of 0.05 μm from the surface relative to ) 0.05μm ) ratio (C 0.05μm / A 2.75μm The ratio (C) is preferably 1.000 or higher, more preferably 2.000 or higher, and even more preferably 3.000 or higher. 0.05μm / A 2.75μm ) is preferably 18.000 or less, more preferably 14.000 or less, and even more preferably 11.000 or less.

[0035] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (A) at a depth of 2.50 to 3.00 μm from the surface. 2.75μm The hydrogen atom concentration (C) at a depth of 0.50 μm from the surface relative to ) 0.5μm ) ratio (C 0.5μm / A 2.75μm The ratio (C) is preferably 2.200 or higher, more preferably 3.000 or higher, and even more preferably 4.000 or higher. 0.5μm / A 2.75μm ) is often 12,000 or less, preferably 10,000 or less, and more preferably 8,000 or less.

[0036] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (A) at a depth of 2.50 to 3.00 μm from the surface. 2.75μm The hydrogen atom concentration (C) at a depth of 1.00 μm from the surface relative to ) 1.0μm ) ratio (C 1.0μm / A 2.75μm The ratio (C) is preferably 1.490 or higher, more preferably 1.600 or higher, even more preferably 2.000 or higher, and particularly preferably 3.000 or higher. 1.0μm / A 2.75μm) is often 10,000 or less, preferably 8,000 or less, and more preferably 6,000 or less.

[0037] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (A) at a depth of 2.50 to 3.00 μm from the surface. 2.75μm The hydrogen atom concentration (C) at a depth of 1.50 μm from the surface relative to ) 1.5μm ) ratio (C 1.5μm / A 2.75μm The ratio (C) is preferably 1.200 or higher, more preferably 1.400 or higher, even more preferably 1.500 or higher, and particularly preferably 2.000 or higher. 1.5μm / A 2.75μm ) is often 10,000 or less, preferably 6,000 or less, and more preferably 4,000 or less.

[0038] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (C) at a depth of 0.50 μm from the surface is 0.5μm ) From the average hydrogen atom concentration (A) at a depth of 2.50 to 3.00 μm from the surface 2.75μm The value obtained by subtracting (C 0.5μm -A 2.75μm ) is 1.500 × 10 20 atoms / cm 3 The above is preferable, 1,800 × 10 20 atoms / cm 3 The above is more preferable, 1,900 × 10 20 atoms / cm 3 The above is even more preferable. Also, the above value is 15.000 × 10 20 atoms / cm 3 In many cases, the following is true: 10.000 × 10 20 atoms / cm 3 The following is preferable: 8,000 × 10 20 atoms / cm 3 The following are preferable.

[0039] Hereinafter, in the chemically strengthened glass of the present invention, the integral approximation of the hydrogen atom concentration at a depth of 0.00 to 1.00 μm from the surface (hereinafter referred to as "I 1.0μmThis section explains how to determine the hydrogen atom concentration (also known as ). First, for each measurement point, calculate the product of the distance from that point to the nearest measurement point that is less deep than the measurement point, and the hydrogen atom concentration at that point. For the measurement point closest to 0.00 μm, calculate the product of the distance from 0.00 μm to the depth of that measurement point and the hydrogen atom concentration at that point. The product obtained above is accumulated over measurement points in the depth range of 0.00 to 1.00 μm from the surface, and the above I 1.0μm We seek. I 1.0μm is 31,000 × 10 15 atoms / cm 2 The above is preferable, 35.000 × 10 15 atoms / cm 2 The above is more preferable, 40,000 × 10 15 atoms / cm 2 The above is even more preferable. Also, I 1.0μm is 150,000 × 10 15 atoms / cm 2 In many cases, the following is true: 120.000 × 10 15 atoms / cm 2 The following is preferable: 100.000 × 10 15 atoms / cm 2 The following are preferable.

[0040] Furthermore, in the chemically strengthened glass of the present invention, the integral approximation of the hydrogen concentration at a depth of 0.00 to 0.1 μm from the surface (hereinafter referred to as "I 0.1μm It is also called ). ) is 5.500 × 10 15 atoms / cm 2 The above is preferable, 6.000 × 10 15 atoms / cm 2 The above is more preferable, 6.300 × 10 15 atoms / cm 2 The above is even more preferable. Also, I 0.1μm is 30,000 × 10 15 atoms / cm 2 In many cases, the following is true: 20,000 × 10 15 atoms / cm 2 The following is preferable: 15,000 × 10 15atoms / cm 2 The following are preferable. I 0.1μm Except for the range, the above I 1.0μm It can be calculated in the same way.

[0041] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (A) at a depth of 0.75 to 1.25 μm from the surface. 1.0μm The integral approximation of the hydrogen concentration at a depth of 0.00 to 1.00 μm from the surface (I 1.0μm ) ratio (I 1.0μm / A 1.0μm ) is 15,000 × 10 -5 Preferably less than 14.500 × 10 -5 Less than 13.500 × 10 -5 It is even more preferable to be less than cm. The above ratio (I 1.0μm / A 1.0μm ) is 2.000 × 10 -5 Often larger than 10 cm, 5.000 × 10 -5 Preferably 8,000 × 10 -5 A length of 1 cm or more is preferable.

[0042] The average hydrogen atom concentration (A) at a depth of 2.50 to 3.00 μm from the surface. 2.75μm ) and the hydrogen atom concentration (C) at a depth of 0.50 μm from the surface. 0.5μm The absolute value of the gradient of hydrogen atom concentration with respect to depth, calculated from ), is 0.600 × 10⁻⁶. 20 atoms / cm 3 • Preferably 0.700 × 10⁻¹⁰ μm or larger. 20 atoms / cm 3 • μm or larger is more preferable, 0.800 × 10 20 atoms / cm 3 A value of μm or greater is even more preferable. The absolute value of the above slope is 10.000 × 10⁻⁶. 20 atoms / cm 3 • Often less than μm. Here, the gradient S of hydrogen atom concentration with respect to depth is calculated using the following formula.

[0043]

number

[0044] [Compressive stress] The chemically strengthened glass of the present invention often has a compressive stress layer on the surface side where compressive stress acts. Preferred parameters related to compressive stress are described below.

[0045] The compressive stress (CS) at a depth of 50 μm of the chemically strengthened glass of the present invention 50 The CS of the chemically strengthened glass of the present invention is preferably 30 MPa or higher, more preferably 40 MPa or higher, and even more preferably 50 MPa or higher, in that it makes the chemically strengthened glass of the present invention less prone to cracking even with greater impacts when other objects collide with it. 50 From the viewpoint of not exceeding the CT limit of the glass, the pressure is often 350 MPa or less, preferably 300 MPa or less, more preferably 250 MPa or less, and even more preferably 200 MPa or less.

[0046] The compressive stress (CS) at a depth of 90 μm of the chemically strengthened glass of the present invention 90 ) is preferably -10 MPa or higher, more preferably 0 MPa or higher, and even more preferably 5 MPa or higher, in that when another object collides with the chemically strengthened glass of the present invention, cracking is less likely to occur even with a greater impact. 90 From the viewpoint of not exceeding the CT limit of the glass, the pressure is often 150 MPa or less, preferably 100 MPa or less, more preferably 75 MPa or less, even more preferably 60 MPa or less, and particularly preferably 45 MPa or less. The compressive stress at each of the depths mentioned above can be calculated by determining the stress profile using the method described above and then determining the stress profile from that profile.

[0047] The compressive stress layer depth DOC of the chemically strengthened glass of the present invention is preferably 80 μm or more, more preferably 90 μm or more, and even more preferably 100 μm or more. The compressive stress layer depth DOC of the chemically strengthened glass of the present invention is preferably 180 μm or less, more preferably 150 μm or less, and even more preferably 130 μm or less.

[0048] Furthermore, with respect to the compressive stress layer depth DOC of the chemically strengthened glass of the present invention, it is preferable that the value of the compressive stress layer depth DOC is 0.16 times or more the thickness of the chemically strengthened glass of the present invention, and more preferably 0.17 times or more. However, the unit of the compressive stress layer depth DOC and the unit of the thickness of the chemically strengthened glass are μm. That is, it is also preferable that the value obtained by dividing the DOC (unit: μm) of the chemically strengthened glass of the present invention by the thickness (unit: μm) is 0.16 times or more, and more preferably 0.17 times or more. The value of the compressive stress layer depth DOC is often 0.25 times or less the thickness of the chemically strengthened glass of the present invention.

[0049] [Tensile stress] The chemically strengthened glass of the present invention often has a compressive stress layer on its surface, but in this case, a tensile stress that balances it acts inside the chemically strengthened glass. The following describes preferred parameters for tensile stress.

[0050] The maximum tensile stress (CT) of the chemically strengthened glass of the present invention Max The pressure is preferably 20 MPa or higher, more preferably 30 MPa or higher, even more preferably 40 MPa or higher, and particularly preferably 50 MPa or higher. Furthermore, the CT of the chemically strengthened glass of the present invention Max The pressure is often 200 MPa or less, preferably 175 MPa or less, more preferably 150 MPa or less, and even more preferably 130 MPa or less. CT Max This is determined from the stress profile and typically acts at the center of the plate thickness.

[0051] Average value of tensile stress (CT) of the chemically strengthened glass of the present invention ave The pressure is preferably 10 MPa or higher, more preferably 20 MPa or higher, and even more preferably 30 MPa or higher. Furthermore, the CT of the chemically strengthened glass of the present invention ave The pressure is often 150 MPa or less, preferably 120 MPa or less, more preferably 100 MPa or less, and even more preferably 90 MPa or less. The average value of tensile stress can be obtained by dividing the integral of tensile stress in the thickness direction of the plate by the length of the tensile stress region in the depth region of the stress profile that exhibits tensile stress.

[0052] The integral tensile stress (ICT) of the chemically strengthened glass of the present invention is often 40,000 Pa·m or less, preferably 35,000 Pa·m or less, and more preferably 30,000 Pa·m or less. The lower limit of ICT is not particularly limited, but it is often 8,000 Pa·m or more, and preferably 10,000 Pa·m or more. ICT is obtained by integrating the tensile stress in the depth region that exhibits tensile stress from the stress profile.

[0053] [plate thickness] The thickness of the chemically strengthened glass of the present invention can be adjusted as appropriate depending on the application, but is often 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.4 mm or more. Furthermore, the thickness of the chemically strengthened glass of the present invention is often 2.0 mm or less, preferably 1.5 mm or less, more preferably 1.2 mm or less, even more preferably 1.0 mm or less, particularly preferably 0.8 mm or less, and may also be 0.7 mm or less.

[0054] [Physical properties] The Young's modulus of the chemically strengthened glass of the present invention is preferably 80 GPa or higher, more preferably 84 GPa or higher, even more preferably 90 GPa or higher, particularly preferably 95 GPa or higher, and most preferably 100 GPa or higher. There is no particular upper limit to the Young's modulus, but it is typically 120 GPa or lower. The Young's modulus of chemically strengthened glass usually coincides with the Young's modulus of glass used for chemical strengthening.

[0055] The fracture toughness value K of the chemically strengthened glass of the present invention IC This is 0.80 MPa·m 1 / 2 The above is preferable, and 0.82 MPa·m 1 / 2 The above is more preferable, 0.85 MPa·m 1 / 2 The above is even more preferable, 0.90 MPa·m 1 / 2The above are particularly preferred, followed in order: 1.00 MPa·m 1 / 2 More than 1.10MPa m 1 / 2 The above is preferable. Fracture toughness value K IC There is no particular upper limit, but it is typically 1.60 MPa·m 1 / 2 The following applies: Fracture toughness value K of chemically strengthened glass IC This is the fracture toughness value K of chemically strengthened glass. IC This usually matches.

[0056] [High temperature and high humidity resistance test] The chemically strengthened glass of the present invention exhibits excellent resistance to high temperatures and high humidity. Specifically, the chemically strengthened glass of the present invention preferably exhibits a haze of 60 times or less, and more preferably 20 times or less, after undergoing a high temperature and high humidity resistance test in which it is left standing for 240 hours in an environment of 85% relative humidity, compared to the haze before the high temperature and high humidity resistance test. The haze before and after the high temperature and high humidity resistance test is measured according to the method described in the examples below. The haze after high temperature and high humidity resistance testing is often more than 1 times greater than the haze before the high temperature and high humidity resistance testing.

[0057] [composition] The chemically strengthened glass of the present invention is obtained by chemically strengthening glass before chemical strengthening (glass for chemical strengthening). The composition of chemically strengthened glass typically coincides with the composition at the center of the glass thickness. That is, the preferred composition at the center of the glass thickness of chemically strengthened glass typically coincides with the preferred composition of glass for chemical strengthening. The composition of chemically strengthened glass is expressed as a mole percentage based on oxides. SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% Li2O at 9.00-40.00%, Na2O at 1.00-8.00%, It is preferable that the product contains 0.00 to 2.00% K2O. The composition of chemically strengthened glass is expressed as a mole percentage based on oxides. SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% P2O5 at 0.00-5.00% Li2O at 9.00-40.00%, Na2O at 1.00-8.00%, K2O at 0.00-2.00% MgO at 0.00-10.00% CaO at 0.00-5.00% It is more preferable to contain 0.00 to 5.00% ZrO2. More preferred compositions for chemically strengthened glass, as well as methods for manufacturing chemically strengthened glass, will be described in detail later.

[0058] Furthermore, it is preferable that the chemically strengthened glass be crystallized glass. When chemically strengthened glass that is crystallized glass is chemically strengthened, chemically strengthened glass that is crystallized glass is obtained. In other words, it is preferable that the chemically strengthened glass of the present invention be crystallized glass. Furthermore, the crystals contained in chemically strengthened glass are also contained in chemically strengthened glass, and the preferred embodiments of the crystals contained in chemically strengthened glass are the same as the preferred embodiments of the crystals contained in chemically strengthened glass. The preferred embodiments when the chemically strengthened glass is crystallized glass are the same as those when the chemically strengthened glass is crystallized glass, so the explanation is omitted.

[0059] <Method for manufacturing chemically strengthened glass> The present invention provides a method for producing chemically strengthened glass, which involves performing a chemical strengthening treatment in which chemically strengthened glass is brought into contact with a molten salt one or more times to obtain chemically strengthened glass. Here, the molten salt used in at least one of the above chemical strengthening treatments satisfies the following requirements 1 and 2. Requirement 1: The above molten salt contains silicic acid. Requirement 2: When the above molten salt is solidified and dissolved in pure water to obtain a 9% by mass aqueous solution, the pH of the aqueous solution must be 6.0 or less. Furthermore, the composition of chemically strengthened glass is expressed as a mole percentage based on oxides. SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% Li2O at 9.00-40.00%, Na2O at 1.00-5.00%, It is preferable that it contains 0.00 to 1.40% K2O. The method for producing the chemically strengthened glass of the present invention will be described below.

[0060] [Chemical strengthening treatment] In the method for producing chemically strengthened glass of the present invention, a chemical strengthening treatment is performed once or more times, in which the chemically strengthened glass is brought into contact with a molten salt. Furthermore, of the above chemical strengthening treatments, the molten salt used in at least one chemical strengthening treatment satisfies requirements 1 and 2 above. Hereinafter, a molten salt that satisfies requirements 1 and 2 above will also be referred to as a "specified molten salt." When chemically strengthened glass is immersed in a molten salt, metal ions with small ionic radii (typically Na ions or Li ions) in the chemically strengthened glass are replaced by metal ions with large ionic radii (typically K ions for Na ions, and Na ions or K ions for Li ions). The following explains chemical strengthening treatment.

[0061] (molten salt) The molten salt used in the method for producing chemically strengthened glass of the present invention will be described. First, the specific molten salts that satisfy requirements 1 and 2 above will be described below.

[0062] The specified molten salt contains silicic acid (Requirement 1). Furthermore, when the specific molten salt is solidified and dissolved in pure water to obtain a 9% by mass aqueous solution, the pH of the aqueous solution must be 6.0 or less (Requirement 2). In this specification, silicic acid refers to a compound consisting of silicon, hydrogen, and oxygen represented by the chemical formula nSiO2·xH2O. In the above chemical formula, n and x are positive real numbers. Specific examples of silicic acid include metasilicic acid (SiO2·H2O), metadisilicate (2SiO2·H2O), orthosilicic acid (SiO2·2H2O), pyrosilicic acid (2SiO2·3H2O), and silica gel. In the present invention, it is preferable that silica gel is included as the silicic acid. Silica gel is a compound represented by the chemical formula SiO2·mH2O (where m is a real number between 0.1 and 1). Silica gel often consists of non-porous primary particles with silanol groups on their surface that aggregate to form secondary particles with minute porosity. The silanol groups of silicic acid (preferably silica gel) interact with alkali ions (e.g., Li ions, Na ions, and K ions) present in the specific molten salt, and can release hydrogen ions. If the released hydrogen ions are present in the specific molten salt, they can be exchanged with Li ions and Na ions contained in the chemically strengthened glass, and hydrogen can be introduced into the chemically strengthened glass. Furthermore, if the specific molten salt contains silicic acid (preferably silica gel), the OH group in the specific molten salt - The amount of hydrogen ions in a specific molten salt increases due to a dehydration reaction between ions and silanol groups in silica. Based on the above principle, silicic acid is thought to lower the pH of the aqueous solution obtained by solidifying a specific molten salt and dissolving it in pure water. However, the principle of pH reduction is not limited to this and may be explained by other principles as well. When the molten salt satisfies requirement 2, a large amount of released hydrogen ions are present, and it is thought that hydrogen is easily introduced through the resulting chemical strengthening. As a result, it is thought that the chemical strengthening glass manufacturing method of the present invention using the above-mentioned specific molten salt can be obtained to obtain chemically strengthened glass that satisfies the above-mentioned requirement for average hydrogen concentration.

[0063] For pH measurement in requirement 2 above, a pH meter (Horiba, Ltd. 9625-D71) shall be used. The measurement temperature shall be 25°C.

[0064] The silicic acid content in the specified molten salt is not particularly limited as long as the specified molten salt satisfies requirements 1 and 2 above. The silicic acid content in the specified molten salt, relative to the mass of the components excluding silicic acid, is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, and particularly preferably 1.0% by mass or more. Furthermore, the silica content relative to the mass of the components of the specific molten salt excluding silica is preferably 15.0% by mass or less, more preferably 10.0% by mass or less, even more preferably 7.0% by mass or less, particularly preferably 5.0% by mass or less, and may also be 3.0% by mass or less.

[0065] The specified molten salt preferably contains one or more metal salts selected from the group consisting of 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 metal salts may be used individually or in combination. In particular, the specific molten salt preferably contains a nitrate, and more preferably contains at least one selected from the group consisting of lithium nitrate, sodium nitrate, and potassium nitrate. In the specific molten salt, the nitrate content relative to the total amount of components excluding silicic acid is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In the specific molten salt, the nitrate content relative to the total amount of components excluding silicic acid may be 100% by mass.

[0066] Furthermore, the ratio of the LiNO3 content (mol%) of the specific molten salt to the Li2O content (mol%) of the chemically strengthened glass, which will be described in detail later, is preferably 75 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. It is also preferable that the above ratio be 0 mol% or more.

[0067] The specified molten salt may contain components other than the above-mentioned metal salt and silicic acid (other components). Other components include heterogeneous anion compounds. Heterogeneous anion compounds are compounds that contain anion species different from those that make up the molten salt. By including heterogeneous anion compounds in the molten salt, the heterogeneous anions in the molten salt react with Li ions, allowing for the adsorption of Li ions in the molten salt. Examples of heterogeneous anionic compounds include heterogeneous sodium anions and heterogeneous potassium anions. Examples of heterogeneous sodium anions include sodium metasilicate, sodium orthosilicate, sodium sesquisilicate, sodium phosphate, and sodium carbonate. Examples of heterogeneous potassium anions include potassium metasilicate, potassium phosphate, and potassium carbonate. These may be used individually or in combination of two or more. Of these, sodium metasilicate and potassium metasilicate are particularly preferred because they exhibit high lithium adsorption effects. That is, the specific molten salt preferably further contains at least one selected from the group consisting of sodium metasilicate and potassium metasilicate, and more preferably contains sodium metasilicate.

[0068] In the method for producing chemically strengthened glass of the present invention, a chemical strengthening treatment using a molten salt other than the specified molten salt may be performed. Hereinafter, the molten salt other than the specified molten salt will also be referred to as "other molten salts". Other molten salts are similar in preferred embodiments to the specified molten salts described above, except that they do not contain silicic acid, so their descriptions are omitted.

[0069] (Number of processing steps) In the method for manufacturing chemically strengthened glass of the present invention, the chemical strengthening treatment is performed one or more times. The number of chemical strengthening treatments may be one or more, two or more, or three or more. In most cases, the number of chemical strengthening treatments is five or less. The number of chemical strengthening treatments refers to the number of times chemical strengthening treatments are performed using molten salts with different compositions.

[0070] If chemical strengthening treatment is performed only once, the specific molten salt described above shall be used for that chemical strengthening treatment. When chemical strengthening treatment is performed multiple times, the specified molten salt described above should be used in at least one of the chemical strengthening treatments. When chemical strengthening treatment is performed multiple times, it is preferable that the specified molten salt is used in two or more chemical strengthening treatments, and it is even more preferable that the specified molten salt is used in all chemical strengthening treatments.

[0071] For example, when performing chemical strengthening treatment three times, it is preferable to use the above-mentioned specific molten salt in the first and second chemical strengthening treatments. In other words, it is preferable to perform chemical strengthening treatment three times, and that the molten salt used in the first and second chemical strengthening treatments satisfies requirements 1 and 2 above. Furthermore, when performing chemical strengthening treatment three times, it is preferable to use the above-mentioned specific molten salt in the first, second, and third chemical strengthening treatments. In other words, it is preferable to perform chemical strengthening treatment three times, and that the molten salt used in the first, second, and third chemical strengthening treatments satisfies requirements 1 and 2 above.

[0072] Furthermore, when chemical strengthening treatment is performed multiple times, the ratio of the LiNO3 content (mol%) of the specific molten salt used in the first chemical strengthening treatment to the Li2O content (mol%) of the chemically strengthened glass, as detailed later, is preferably 75 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. It is also preferable that the above ratio be 0 mol% or more.

[0073] (Processing conditions) In the method for manufacturing chemically strengthened glass of the present invention, the temperature of each chemical strengthening treatment is preferably 300°C or higher, more preferably 350°C or higher, and even more preferably 370°C or higher. The temperature of the chemical strengthening treatment refers to the temperature of the molten salt into which the chemically strengthened glass is immersed. The temperature for each chemical strengthening treatment is preferably 500°C or lower, and more preferably 470°C or lower.

[0074] In the method for manufacturing chemically strengthened glass of the present invention, the duration of each chemical strengthening treatment is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 20 minutes or more. Furthermore, the duration of each chemical strengthening treatment is often 720 minutes or less, preferably 600 minutes or less, more preferably 420 minutes or less, and even more preferably 360 minutes or less. Here, the ratio of the total time of chemical strengthening treatment using the specified molten salt to the total time of chemical strengthening treatment performed in the method for manufacturing chemically strengthened glass of the present invention is preferably 0.65 or higher, more preferably 0.80 or higher, and even more preferably 0.90 or higher, from the viewpoint of obtaining a more preferred embodiment of the chemically strengthened glass of the present invention. The above ratio may also be 1.00.

[0075] [Chemically strengthened glass] (composition) The composition of the chemically strengthened glass used in the method for manufacturing chemically strengthened glass of the present invention will be described below. Hereinafter, the preferred composition of the chemically strengthened glass will also be referred to as the "master glass composition". The composition of chemically strengthened glass (matrix glass composition) is expressed as a mole percentage based on oxides. SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% Li2O at 9.00-40.00%, Na2O at 1.00-8.00%, It is preferable that the product contains 0.00 to 2.00% K2O. Furthermore, the composition of the mother glass is expressed as a mole percentage based on oxides. SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% Li2O at 9.00-40.00%, Na2O at 1.00-5.00%, It is also preferable to contain 0.00 to 1.40% K2O.

[0076] The preferred composition of the chemically strengthened glass of the present invention (matrix glass composition) is expressed in mole percentage based on oxides, SiO2 at 40.00-75.00%, Al2O3 at 2.00-20.00% P2O5 at 0.00-5.00% Li2O at 9.00-40.00%, Na2O at 1.00-8.00%, K2O at 0.00-2.00% MgO at 0.00-10.00% CaO at 0.00-5.00% It is more preferable to contain 0.00 to 5.00% ZrO2. The following describes each component included in the composition of the mother glass.

[0077] SiO2 is a component that makes up the network of glass. It is also a component that increases chemical durability and reduces the occurrence of cracks when the glass surface is scratched.

[0078] To improve chemical durability, the SiO2 content is more preferably 42.00% or more, even more preferably 45.00% or more, and particularly preferably 48.00% or more. On the other hand, from the viewpoint of improving melting properties, the SiO2 content is more preferably 74.00% or less, even more preferably 72.00% or less, and particularly preferably 70.00% or less.

[0079] Al2O3 is a component that improves ion exchange performance during chemical strengthening and increases the surface compressive stress after strengthening. It also contributes to the formation of crystals containing Al and Li. From the viewpoint of obtaining the above effects, the Al2O3 content is more preferably 3.00% or more, even more preferably 3.50% or more, particularly preferably 4.00% or more, and most preferably 4.05% or more. On the other hand, it is sometimes required that crystal growth be hindered during melting, that devitrification defects be less likely to occur, that the yield tends to be higher, and that the high-temperature viscosity of the glass be reduced to facilitate melting. From this viewpoint, the Al2O3 content is more preferably 18.00% or less, even more preferably 15.00% or less, and then 12.00% or less.

[0080] SiO2 and Al2O3 are both components that stabilize the structure of glass. To reduce brittleness, the total content of SiO2 and Al2O3 is preferably 45.00% or more, more preferably 50.00% or more, and even more preferably 55.00% or more. Furthermore, both SiO2 and Al2O3 tend to increase the melting temperature of glass. Therefore, in order to make it easier to melt, the total content of SiO2 and Al2O3 is preferably 80.00% or less, and more preferably 78.00% or less.

[0081] Li2O is an ion-exchangeable component that improves the meltability of glass. When glass contains Li2O, Li ions on the glass surface are exchanged with external Na ions and incorporated into the glass, and these incorporated Na ions are then exchanged with external K ions. This method makes it easier to obtain a stress profile with high surface compressive stress and a thick compressive stress layer. Furthermore, including Li2O within the above range makes it easier to obtain crystallized glass when subjected to specific heat treatments. From the above viewpoint, a Li2O content of 9.05% or more is more preferable, and 10.00% or more is even more preferable.

[0082] On the other hand, from the viewpoint of reducing the crystal growth rate during glass molding and minimizing quality degradation due to devitrification, the Li2O content is more preferably 38.00% or less, and even more preferably 36.00% or less.

[0083] Na2O and K2O are components that improve the meltability of glass and reduce the crystal growth rate during glass molding. It is also preferable to include small amounts of these components to improve ion exchange performance.

[0084] Na2O is a component that can undergo ion exchange in chemical strengthening treatment using potassium salts, and also a component that reduces the viscosity of glass. To obtain the above effects, the Na2O content is preferably 1.00% or more, and more preferably 1.20% or more, 1.40% or more, and 1.60% or more, in that order. On the other hand, from the viewpoint of maintaining the glass network and avoiding a decrease in surface compressive stress (Na_CS) in the strengthening treatment with sodium salts, the Na2O content is more preferably 7.00% or less, even more preferably 6.00% or less, and particularly preferably 5.00% or less.

[0085] K2O is a component that suppresses devitrification by inhibiting the rise in devitrification temperature, and also improves ion exchange performance. The K2O content is more preferably 0.03% or more, even more preferably 0.05% or more, particularly preferably 0.10% or more, and most preferably 0.50% or more. On the other hand, from the viewpoint of avoiding a decrease in surface compressive stress (K_CS) during the strengthening treatment with sodium salts, the K2O content is more preferably 1.80% or less, even more preferably 1.50% or less, and particularly preferably 1.40% or less. Furthermore, K2O does not necessarily need to be included.

[0086] The sum of the Li2O, Na2O, and K2O content, R, is more preferably 10.00 to 45.00%, even more preferably 15.00 to 40.00%, and particularly preferably 17.00 to 38.00%, from the viewpoint of suppressing the rise in devitrification temperature and reducing the crystal growth rate.

[0087] The ratio of Li2O content to R ([Li2O] / ([Li2O]+[Na2O]+[K2O]), hereinafter also referred to as "Li2O / R2O") is more preferably 0.50 or higher, and even more preferably 0.55 or higher, from the viewpoint of further improving deep stress in chemical strengthening properties. From the viewpoint of further improving chemical resistance, Li2O / R2O is more preferably 0.99 or lower, even more preferably 0.98 or lower, and particularly preferably 0.95 or lower.

[0088] The ratio of Na2O content to R ([Na2O] / ([Li2O]+[Na2O]+[K2O]), hereinafter also referred to as "Na2O / R2O") is preferably greater than 0, more preferably 0.01 or greater, even more preferably 0.02 or greater, and particularly preferably 0.04 or greater, from the viewpoint of further improving the deep stress in chemical strengthening properties. From the viewpoint of further improving chemical resistance, Na2O / R2O is preferably 0.40 or less, and more preferably 0.35 or less.

[0089] The ratio of K2O content to R ([K2O] / ([Li2O]+[Na2O]+[K2O]), hereinafter also referred to as "K2O / R2O") is preferably 0.001 or higher, more preferably 0.004 or higher, and even more preferably 0.01 or higher, from the viewpoint of further increasing the electrical resistance of the glass. From the viewpoint of increasing the compressive stress near the surface in the chemical strengthening properties, the K2O / R2O ratio is preferably 0.50 or lower, more preferably 0.40 or lower, even more preferably 0.30 or lower, and particularly preferably 0.20 or lower. Note that the K2O / R2O ratio may be 0.

[0090] Furthermore, the product of Li2O / R2O, Na2O / R2O, and K2O / R2O is more preferably 0.00005 or higher, and even more preferably 0.0001 or higher, from the viewpoint of suppressing the rise in devitrification temperature and reducing the crystal growth rate. Moreover, the above product is more preferably 0.020 or lower. Note that the above product may be zero.

[0091] The ratio of Al2O3 content to R ([Al2O3] / ([Li2O]+[Na2O]+[K2O]), hereinafter also referred to as "Al2O3 / R2O") is preferably 0.05 or higher, more preferably 0.10 or higher, even more preferably 0.12 or higher, and even more preferably 0.13 or higher. Al2O3 / R2O is preferably 0.80 or lower, more preferably 0.75 or lower, and even more preferably 0.70 or lower.

[0092] The value represented by [Al2O3]-[Na2O]-[K2O]+[Li2O] is preferably 10.00% or more, and more preferably 14.00% or more. Furthermore, the above value is preferably 40.00% or less, and more preferably 37.00% or less.

[0093] MgO may be included to reduce viscosity during dissolution, etc. The MgO content is more preferably 0.05% or more, and even more preferably 0.50% or more, 1.00% or more, 2.00% or more, and 3.00% or more, in that order. On the other hand, in terms of making it easier to increase the compressive stress layer during chemical strengthening treatment, the MgO content is more preferably 9.00% or less, and even more preferably 8.00% or less, 7.00% or less, and 6.00% or less, in that order.

[0094] Furthermore, the inclusion of MgO can suppress the phase transition of the crystalline phase from the β-quartz solid solution to β-spodumene, thereby suppressing the precipitation of β-spodumene crystals. Therefore, in Embodiment 2, it is preferable to include MgO. From the above viewpoint, it is preferable to contain more than 0.5% and 7.0% or less of MgO. The more preferable range is as described above. MgO can be practically omitted.

[0095] CaO is a component that improves the meltability of glass and may be included. The CaO content is more preferably 0.005% or more, and even more preferably 0.01% or more. On the other hand, in terms of easily increasing the compressive stress value during chemical strengthening treatment, the CaO content is more preferably 2.00% or less, even more preferably 1.00% or less, particularly preferably 0.80% or less, and most preferably 0.50% or less.

[0096] SrO is an ingredient that improves the meltability of the glass and may be included. The SrO content is more preferably 0.10% or more, even more preferably 0.15% or more, and particularly preferably 0.50% or more. In order to facilitate increasing the compressive stress value during chemical strengthening treatment, the SrO content is more preferably 3.00% or less, even more preferably 2.00% or less, particularly preferably 1.00% or less, and most preferably 0.50% or less. SrO can be practically omitted.

[0097] BaO is an ingredient that improves the meltability of glass and may be included. If BaO is included, the content is preferably 0.10% or more, more preferably 0.15% or more, and even more preferably 0.50% or more. In order to facilitate increasing the compressive stress value during chemical strengthening treatment, the BaO content is preferably 3.0% or less, more preferably 2.00% or less, even more preferably 1.00% or less, and particularly preferably 0.50% or less. BaO can be effectively omitted.

[0098] ZnO is a component that improves the meltability of glass. The ZnO content is more preferably 0.10% or more, even more preferably 0.15% or more, and particularly preferably 0.50% or more. In order to facilitate increasing the compressive stress value during chemical strengthening treatment, the ZnO content is more preferably 3.00% or less, even more preferably 2.00% or less, particularly preferably 1.00% or less, and most preferably 0.50% or less. ZnO can be practically omitted.

[0099] lnW is a parameter that represents the degree of oxide mixing, calculated from the content of alkali metal oxides, alkaline earth metal oxides, and zinc oxide in the glass. lnW is expressed by the following formula. lnW=ln(([Li2O]+[Na2O]+[K2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO])! / ([Li 2O]!×[Na2O]!×[K2O]!×[MgO]!×[CaO]!×[SrO]!×[BaO]!×[ZnO]!))...Formula (W1) In formula (W1), [Li2O], [Na2O], [K2O], [MgO], [CaO], [SrO], [BaO], and [ZnO] represent the content of each component, Li2O, Na2O, K2O, MgO, CaO, SrO, BaO, and ZnO, expressed as a mole percentage on an oxide basis. Furthermore, ! indicates raising a positive integer to a factorial. For example, [XO]! means taking the molar percentage content of component XO on an oxide basis, truncating the decimal part to an integer, and then raising that integer to a factorial. For example, if Na2O is 4.80 mol%, the calculation would be the factorial of "4", i.e., 4 × 3 × 2 × 1. A larger lnW value indicates a higher degree of mixing of the metal oxides, thereby suppressing glass devitrification. From this viewpoint, lnW is preferably 10 or higher, more preferably 12 or higher, even more preferably 13 or higher, and particularly preferably 14 or higher. lnW is preferably 20 or lower, more preferably 18 or lower, and even more preferably 17 or lower.

[0100] TiO2 is a component that is highly effective in suppressing the solarization of glass and is a material that forms crystal nuclei, so it may be included. When TiO2 is included, the content is preferably 0.05% or more, and more preferably 0.10% or more. On the other hand, since TiO2 has light absorption properties, from the viewpoint of preventing discoloration of the glass, the TiO2 content is preferably 2.50% or less, more preferably 2.00% or less, even more preferably 1.50% or less, and particularly preferably 1.00% or less. TiO2 does not necessarily need to be included.

[0101] ZrO2 is a component that facilitates increasing the surface compressive stress of chemically strengthened crystallized glass. Furthermore, since it is a material that forms crystal nuclei, it may be included. The ZrO2 content is more preferably greater than 0.00%, and even more preferably 0.50% or more, 1.00% or more, and 1.20% or more, in that order. The ZrO2 content is more preferably 4.80% or less, and even more preferably 4.60% or less.

[0102] P2O5 tends to increase the compressive stress layer during chemical strengthening. The P2O5 content is more preferably 0.20% or more, and even more preferably 0.50% or more. On the other hand, from the viewpoint of increasing acid resistance, the P2O5 content is more preferably 3.00% or less, and even more preferably 2.00% or less. From the viewpoint of preventing striations from forming during melting, it is also preferable for it to be substantially absent.

[0103] B2O3 reduces the brittleness of glass, improves its crack resistance, or improves its meltability. The B2O3 content is preferably 0.50% or more, more preferably 1.00% or more, and even more preferably 1.20% or more. On the other hand, in terms of maintaining good acid resistance, the B2O3 content is preferably 8.00% or less. More preferably, the B2O3 content is 6.00% or less, even more preferably 4.00% or less, and particularly preferably 2.00% or less. From the viewpoint of preventing striation formation during melting, it is also preferable that it be substantially absent.

[0104] Y2O3 is a component that facilitates increasing the surface compressive stress of chemically strengthened crystallized glass while reducing the crystal growth rate. The Y2O3 content is preferably more than 0.00%, and more preferably 0.10% or more, 0.20% or more, and 0.50% or more, in that order. On the other hand, in terms of facilitating the creation of a larger compressive stress layer during chemical strengthening, the Y2O3 content is more preferably 2.00% or less, and even more preferably 1.50% or less. Y2O3 does not necessarily need to be included.

[0105] From the viewpoint of improving initial solubility, the total content of ZrO2 and Y2O3 is more preferably 6.00% or less. There is no particular lower limit to the total content of ZrO2 and Y2O3, but from the viewpoint of increasing the strength of the glass, it is more preferably 0.50% or more, and even more preferably 1.00% or more, and 1.50% or more, in that order.

[0106] La2O3 is not essential, but can be included for the same reasons as Y2O3. The amount of La2O3 is preferably 0.10% or more, more preferably 0.20% or more, even more preferably 0.50% or more, and particularly preferably 0.8% or more. On the other hand, if there is too much, it becomes difficult to enlarge the compressive stress layer during chemical strengthening treatment, so the amount of La2O3 is preferably 5.00% or less, more preferably 3.00% or less, even more preferably 2.00% or less, and particularly preferably 1.50% or less. It is also preferable that La2O3 is substantially absent.

[0107] Nb2O 5、 Ta2O5, Gd2O3, and CeO2 are components that have the effect of suppressing the solarization of glass and improving meltability, and may be included. When these components are included, the content of each is preferably 0.03% or more, more preferably 0.10% or more, even more preferably 0.50% or more, particularly preferably 0.80% or more, and most preferably 1.00% or more. On the other hand, it is preferably 3.00% or less, more preferably 2.00% or less, and even more preferably 1.00% or less.

[0108] Since Fe2O3 absorbs heat rays, it has the effect of improving the solubility of glass. When producing glass in large quantities using a large melting furnace, it is preferably contained. In that case, the content is preferably 0.002% or more, more preferably 0.005% or more, still more preferably 0.007% or more, and particularly preferably 0.01% or more in terms of mass% based on the oxide. On the other hand, if Fe2O3 is contained in excess, coloring occurs. Therefore, from the viewpoint of enhancing the transparency of the glass, the content is preferably 0.30% or less, more preferably 0.04% or less, still more preferably 0.025% or less, and particularly preferably 0.015% or less in terms of mass% based on the oxide.

[0109] Furthermore, other coloring components may be added as long as the achievement of the desired chemical strengthening characteristics is not inhibited. Examples of other coloring components include Co3O4, MnO2, NiO, CuO, Cr2O3, V2O5, Bi2O3, SeO2, Er2O3, Nd2O3, etc.

[0110] As a fining agent or the like during the melting of glass, SO3, chlorides, fluorides, etc. may be appropriately contained. It is preferably not to contain As2O3. When containing Sb2O3, it is preferably 0.30% or less, more preferably 0.10% or less, and most preferably not to contain it. From the viewpoint of fining the bubbles in the glass, the content of SnO2 is more preferably 0.05% or more, and still more preferably 0.07% or more. Also, the content of SnO2 is preferably 1.00% or less, more preferably 0.80% or less, still more preferably 0.70% or less, and particularly preferably 0.50% or less in order to suppress the occurrence of defects.

[0111] The glass for chemical strengthening is preferably a crystallized glass. As the crystals contained in the crystallized glass, for example, one or more crystals selected from the group consisting of lithium silicate crystals, lithium aluminosilicate crystals, and lithium phosphate crystals are preferable, and one or more crystals selected from the group consisting of lithium silicate crystals and lithium aluminosilicate crystals are more preferable. As the lithium silicate crystals, lithium metasilicate (Li2SiO3) crystals, lithium disilicate crystals (Li2Si2O5), etc. are preferable. As the lithium phosphate crystals, lithium orthophosphate crystals (Li3PO4), etc. are preferable. As the lithium aluminosilicate crystals, β-spodumene crystals (LiAlSi2O6), β-quartz solid solution crystals (LiAlSiO4), petalite crystals (LiAlSi4O 10 ) etc. are preferable. Moreover, it is also preferable that the obtained crystallized glass contains one or more crystals selected from the group consisting of lithium disilicate crystals, β-spodumene crystals, β-quartz solid solution crystals, and petalite crystals.

[0112] When the glass for chemical strengthening is crystallized glass, the crystallization rate is preferably 10% or more, more preferably 15% or more, further preferably 20% or more, and particularly preferably 25% or more in terms of improving the mechanical strength. Also, in order to enhance transparency, it is preferably 70% or less, more preferably 60% or less, and further preferably 50% or less. The fact that the crystallization rate is small is also excellent in terms of being easy to heat and bend and form. The crystallization rate can be calculated by the Rietveld method from the X-ray diffraction intensity. The Rietveld method is described in the "Crystallography Handbook" (published by Kyoritsu Shuppan in 1999, p492 - 499), edited by the Editorial Committee of the "Crystallography Handbook" of the Japan Crystallographic Society.

[0113] <00009 (Physical properties) The following describes the desirable physical properties of chemically strengthened glass.

[0115] Chemically strengthened glass is preferably devitrified at a temperature of 1300°C or lower. More preferably at 1280°C or lower, and even more preferably at 1250°C or lower. Particularly preferred are, in order, 1240°C or lower, 1230°C or lower, 1220°C or lower, and 1210°C or lower. The lower limit of the devitrification temperature is not particularly limited, but is usually 1100°C or higher.

[0116] For chemically strengthened glass (for example, glass with the above-mentioned mother glass composition), a crystallization onset temperature Tcs measured by DSC is preferably 500°C or higher. There is no particular upper limit to the crystallization onset temperature, but it is usually 800°C or lower.

[0117] If the crystallization onset temperature Tcs is within the above range, then, for example, by performing a heat treatment in which the glass is held at 500-600°C for 1-6 hours and then at 600-800°C for 0.5-6 hours, crystals can be precipitated in the glass, and a chemically strengthened glass, which is a crystallized glass, can be obtained. The above heat treatment may be carried out in three stages. For example, chemically strengthened glass may be obtained by holding at 500-600°C for 1-6 hours, 550-650°C for 0.5-6 hours, and 600-800°C for 0.5-6 hours.

[0118] The glass transition temperature (Tg) is preferably 500°C or higher, more preferably 520°C or higher, and even more preferably 540°C or higher, from the viewpoint of reducing warping after chemical strengthening. From the viewpoint of ease of float molding, it is preferably 750°C or lower, more preferably 700°C or lower, even more preferably 650°C or lower, particularly preferably 600°C or lower, and most preferably 580°C or lower.

[0119] The chemically strengthened glass having the above-described matrix glass composition preferably has a crystallization peak temperature Tc of 600°C or higher, more preferably 650°C or higher, and even more preferably 700°C or higher. A crystallization peak temperature Tc of 600°C or higher allows for stable molding. It is most preferable that no crystallization peak is observed. There is no particular upper limit to the crystallization peak temperature Tc, but it is usually 950°C or lower.

[0120] Chemically strengthened glass has a β-OH value of 0.1 mm -1 Preferably, it is 0.15 mm or more. -1 The above is more preferable, 0.2 mm -1 The above is even more preferable, 0.22 mm -1 The above is particularly preferred, 0.25 mm -1 The above is the most preferable option.

[0121] The β-OH value is an indicator of the water content in glass. Glass with a high β-OH value tends to have a lower softening point and is easier to bend. On the other hand, from the perspective of improving the strength of glass through chemical strengthening, a higher β-OH value in glass tends to result in a lower surface compressive stress (CS) after chemical strengthening treatment. From the above perspective, a β-OH value of 0.5 mm is considered to be a good indicator. -1 The following is preferred: 0.4 mm -1 The following is more preferable: 0.3 mm -1 The following are even more preferable.

[0122] Chemically strengthened glass has a fracture toughness value (K IC ) However, 0.80 MPa·m 1 / 2 Preferably, it is 0.85 MPa·m 1 / 2 It is more preferable that the value be greater than or equal to 0.90 MPa·m 1 / 2 It is even more preferable that the pressure be greater than or equal to 1.00 MPa·m, and particularly preferable that it be 1.00 MPa·m. 1 / 2 In summary, the most preferred value is 1.10 MPa·m. 1 / 2 That concludes the explanation. There is no particular upper limit to the fracture toughness value, but it is typically 1.60 MPa·m. 1 / 2 The following applies:

[0123] Chemically strengthened glass preferably has a Young's modulus of 80 GPa or higher, more preferably 85 GPa or higher, even more preferably 90 GPa or higher, particularly preferably 95 GPa or higher, and most preferably 100 GPa or higher. There is no particular upper limit to the Young's modulus, but it is typically 120 GPa or lower. The method for measuring the Young's modulus of chemically strengthened glass follows the method described in the examples section below.

[0124] <Application> The chemically strengthened glass of the present invention is useful, for example, as a cover glass. The above-mentioned cover glass can also be suitably used for surface protection purposes such as for displays and solar cell modules. In particular, the chemically strengthened glass of the present invention is useful as cover glass for mobile devices such as mobile phones, smartphones, personal digital assistants (PDAs), and tablet devices. Furthermore, it is useful for cover glass for display devices such as televisions (TVs), personal computers (PCs), and touch panels that are not intended to be portable, as well as for cover glass provided on the surface of solar cell modules, building materials such as elevator walls, walls of buildings such as houses and office buildings (full-surface displays), and window glass, and also for interiors of tabletops, automobiles, and airplanes. It is also useful as cover glass for the above-mentioned articles. Furthermore, it can be applied to applications such as casings with curved shapes by bending and bending. Because the chemically strengthened glass of the present invention has excellent resistance to high temperatures and high humidity, it can be suitably applied to applications used in high-temperature and high-humidity environments. [Examples]

[0125] The present invention will be described in more detail below based on examples. The materials, quantities, proportions, processing details, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples. Note that Examples 1 to 3, Example 5, Example 7, and Example 9 described below are examples, Example 4, Example 8, and Example 10 are comparative examples, and Example 6 is a reference example.

[0126] <Preparation of Chemically Strengthened Glass> First, glass raw materials were melted in a platinum crucible to obtain frit materials A to D so as to have the composition of each glass shown in Table 1 in terms of molar percentage based on oxides. More specifically, oxides, hydroxides, carbonates, or nitrates used as glass raw materials were appropriately selected from generally used glass raw materials and weighed so as to be 1000 g as glass. Next, the mixed raw materials were put into a platinum crucible, charged into a resistance heating electric furnace at 1500 to 1700 °C, melted for about 3 hours, defoamed and homogenized to obtain molten glass. The obtained molten glass was poured into a shaped material, held at a temperature 50 °C higher than the glass transition point for 1 hour, and then cooled to room temperature at a rate of 0.5 °C / min to obtain a glass block. The obtained glass block was cut and ground to obtain sheet glass. The thickness of the sheet glass was as shown in Tables 2 and 3.

[0127] Note that after the frit material A was made into sheet glass, it was heated to 550 °C, held for 2 hours, then heated to 720 °C, and heat-treated under the condition of holding for 2 hours. Also, after the frit material C was made into sheet glass, it was heated to 540 °C, held for 4 hours, then heated to 600 °C, held for 4 hours, then heated to 700 °C, and heat-treated under the condition of holding for 2 hours. Also, after the frit material D was made into sheet glass, it was heated to 5� °C, held for 2 hours, then heated to 720 °C, and heat-treated under the condition of holding for 2 hours. By the above heat treatment, a crystallized glass with crystals precipitated was obtained. The obtained crystallized glass was used as chemically strengthened glass. The crystals precipitated after the above heat treatment and the degree of crystallinity are shown in Table 1 in the following section, respectively.

[0128] Also, the same heat treatment as above was separately performed on a glass block, and the fracture toughness value (K ICSample pieces for measurement and sample pieces for measuring Young's modulus were obtained, and the fracture toughness value and Young's modulus were measured using the method described later.

[0129] [Table 1]

[0130] <Fabrication of chemically strengthened glass> The chemically strengthened glass (glass material A to glass material D) obtained by the above procedure was subjected to chemical strengthening treatment under the conditions described in Tables 2 and 3 to obtain the chemically strengthened glass for each example. Silica gel (average particle size 1.3 mm, specific surface area 450 m²) was used as the added silica. 2 (A sample size of 0.75 ml / g with a pore volume of 0.75 ml / g and a pore diameter of 6 nm was used.) Tables 2 and 3 also show the pH of the aqueous solution (labeled "Aqueous Solution pH" in Tables 2 and 3) obtained by solidifying the molten salt used in the chemical strengthening treatment, dissolving it in pure water, and preparing a 9% by mass aqueous solution.

[0131] <Hydrogen atom flavor> The hydrogen atom concentration was measured using the procedure described above, and each parameter was calculated. The meaning of each parameter is as described above.

[0132] <Measurement of Young's modulus> In the procedure for obtaining each of the above glass materials, the Young's modulus of the chemically strengthened glass was measured using the cut sample pieces. Specifically, the measurement was performed using the ultrasonic pulse method with the above sample pieces in accordance with JIS R 1602. Furthermore, when Young's modulus was measured using the same method after chemical strengthening, it was the same as the value before chemical strengthening.

[0133] <Measurement of fracture toughness value> In the procedure for obtaining each of the above glass materials, the fracture toughness value K of the chemically strengthened glass is determined using the cut sample pieces. IC The following measurements were performed. Fracture toughness values ​​were measured using the DCDC method described above. Furthermore, the fracture toughness value K was determined using the same method after chemical strengthening. ICWhen measured, the values ​​were similar to those before chemical strengthening.

[0134] <Evaluation of resistance to high temperature and high humidity> The high-temperature and high-humidity resistance of each example of chemically strengthened glass was evaluated according to the following procedure. Specifically, first, each example of chemically strengthened glass was cut into 5cm squares to serve as test samples. The obtained test samples were placed in a constant temperature and humidity chamber (ESPEC SH-642) and left to stand for 240 hours under conditions of 85°C and 85% relative humidity. After allowing each test sample to stand, the haze of each test sample was measured. Additionally, the haze of each test sample was measured before allowing it to stand. Haze was measured using the HZ-V3 manufactured by Suga Test Instruments Co., Ltd. under the following conditions. Optical conditions: Double-beam system (JIS K7361.7136) Light source: C light The table below shows the haze after the high-temperature, high-humidity test, and the ratio of the haze after the high-temperature, high-humidity test to the haze before the test. Furthermore, high temperature and high humidity resistance is evaluated by comparing each glass material. Specifically, for each glass material, the ratio of the highest haze among chemically strengthened glass obtained by chemical strengthening treatment without adding silica (silica gel) during the chemical strengthening treatment is compared with the ratio of the haze of each chemically strengthened glass. More specifically, for glass material A, the ratio of the haze before and after the high temperature and high humidity test in Example 4 is compared with the ratio of the haze in Examples 1 to 3 and Example 5.

[0135] <Stress Measurement> As described above, stress profiles were obtained using a scattered photoelastic stress meter, and various parameters related to compressive stress and tensile stress were calculated. The various parameters related to compressive stress and tensile stress are as described above.

[0136] <Result> Tables 2 and 3 show the type of chemically strengthened glass, chemical strengthening conditions, measurement results, and evaluation results for each example. Table 4 shows the stress parameters obtained from the stress profiles. In Tables 2 and 3, the silica gel content indicates the silica gel content relative to the total mass of the molten salt excluding silica gel.

[0137] [Table 2]

[0138] [Table 3]

[0139] [Table 4]

[0140] From the results shown in Tables 2 and 3, when glass material A is used as chemically strengthened glass, A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 The chemically strengthened glass of the present invention described in Examples 1 to 3 and Example 5 above is A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 Compared to the chemically strengthened glass of Example 4, which had a haze value less than [value missing], the haze value after the high-temperature and high-humidity test was smaller, confirming superior resistance to high temperatures and humidity. In relation to this, SIMS analysis was performed on glass material A using the same method as for obtaining the hydrogen atom concentration profile, and the atomic concentration profiles of Na and K were measured, as shown in Table 4. In Table 5, for example, in the "Na concentration" column, "C 0.5μm The description is the same as in Table 3, and represents the concentration of Na atoms at a depth of 0.50 μm from the surface. The other descriptions are also the same. Furthermore, the "Na+K" column shows the sum of the values ​​of the corresponding parameters in the "Na concentration" column and the corresponding parameters in the "K concentration" column.

[0141] [Table 5]

[0142] From the results shown in Table 5, when comparing the chemically strengthened glass of the present invention (Examples 1 to 3 and 5) with the chemically strengthened glass of Example 4, the ratio of the sum of the Na atom concentration and K atom concentration at a depth of 0.50 μm from the surface to the sum of the average Na atom concentration and average K atom concentration at a depth of 2.50 to 3.00 μm from the surface (C 0.5μm / A 2.75μm The ratio of K atom concentrations (C) is small. Furthermore, when comparing the chemically strengthened glass of the present invention (Examples 1 to 3 and Example 5) with the chemically strengthened glass of Example 4, the ratio of K atom concentrations (C) is small. 0.5μm / A 2.75μm ) is small. In other words, the chemically strengthened glasses of Examples 1-3 and Example 5 have relatively lower Na concentrations near the surface and relatively lower K concentrations near the surface compared to the chemically strengthened glass of Example 4. Therefore, due to the mechanism described above, the chemically strengthened glass of the present invention is expected to exhibit less haze even in high-temperature and high-humidity environments.

[0143] From the results shown in Tables 2 and 3, when glass material B is used as a chemically strengthened glass and chemical strengthening is performed using a molten salt that satisfies the above requirements 1 and 2 (Example 6), A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 It did not go any further than that. From the results shown in Tables 2 and 3, when glass material C is used as chemically strengthened glass, A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 The chemically strengthened glass of the present invention in Example 7, as described above, is A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 Compared to the chemically strengthened glass of Example 8, which had a haze value less than [value missing], the haze value after the high-temperature and high-humidity test was smaller, confirming superior resistance to high temperatures and humidity. Similarly, from the results shown in Tables 2 and 3, when glass material D is used as chemically strengthened glass, A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 The chemically strengthened glass of the present invention in Example 9, as described above, is A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 Compared to the chemically strengthened glass of Example 10, which had a haze value less than [value missing], the haze value after the high-temperature and high-humidity test was smaller, confirming superior resistance to high temperatures and high humidity.

Claims

1. It is a chemically strengthened glass, The average hydrogen atom concentration at a depth of 0.75 to 1.25 μm from the surface is 2,000 × 10⁻¹⁴. ２０ atoms / cm ３ That concludes our explanation of chemically strengthened glass.

2. The chemically strengthened glass according to claim 1, wherein the ratio of the hydrogen atom concentration at a depth of 1.00 μm from the surface to the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface is 1.490 or more.

3. The chemically strengthened glass according to claim 1 or 2, wherein the ratio of the hydrogen atom concentration at a depth of 1.50 μm from the surface to the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface is 1.250 or more.

4. The absolute value of the slope of hydrogen atom concentration with respect to depth, calculated from the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the surface and the hydrogen atom concentration at a depth of 0.50 μm from the surface, is 0.600 × 10⁻¹⁰. ２０ atoms / cm ３ - Chemically strengthened glass according to claim 1 or 2, wherein the thickness is μm or greater.

5. The value obtained by subtracting the average hydrogen atom concentration at a depth of 2.50 to 3.00 μm from the hydrogen atom concentration at a depth of 0.50 μm from the surface is 1.800 × 10⁻¹⁰ ２０ atoms / cm ３ The chemically strengthened glass according to claim 1 or 2.

6. The ratio of the integral approximation of the hydrogen atom concentration at a depth of 0.00 to 1.00 μm from the surface to the average hydrogen atom concentration at a depth of 0.75 to 1.25 μm from the surface is 15.000 × 10⁻¹⁰ －５ A chemically strengthened glass according to claim 1 or 2, wherein the thickness is less than or equal to cm.

7. The chemically strengthened glass according to claim 1 or 2, which is a crystallized glass.

8. The chemically strengthened glass according to claim 7, comprising one or more crystals selected from the group consisting of lithium silicate crystals, lithium aluminosilicate crystals, and lithium phosphate crystals.

9. The chemically strengthened glass according to claim 7, wherein the crystallinity is 10 to 70%.

10. The composition of the aforementioned chemically strengthened glass is expressed as a mole percentage based on oxides, SiO ２ 40.00-75.00% Al ２ O ３ を2.00~20.00%、 Li ２ Oを9.00~40.00%、 Na ２ Oを1.00~8.00%、 K ２ A chemically strengthened glass according to claim 1 or 2, containing 0.00 to 2.00% of oxygen.

11. The chemically strengthened glass according to claim 1 or 2, wherein the haze after a high-temperature and high-humidity resistance test, in which the glass is left standing for 240 hours in an environment of 85°C and 85% relative humidity, is 20 times or less than the haze before the high-temperature and high-humidity resistance test.

12. The chemically strengthened glass according to claim 1 or 2, wherein the plate thickness is 2.0 mm or less.

13. Fracture toughness value K ＩＣ However, 0.82 MPa·m １／２ The chemically strengthened glass according to claim 1 or 2.

14. A chemically strengthened glass according to claim 1 or 2, wherein the Young's modulus is 84 GPa or higher.

15. A method for producing chemically strengthened glass, comprising performing a chemical strengthening treatment in which chemically strengthened glass is brought into contact with a molten salt one or more times, The composition of the aforementioned chemically strengthened glass is expressed as a mole percentage based on oxides, SiO ２ 40.00-75.00% Al ２ O ３ を2.00~20.00%、 Li ２ Oを9.00~40.00%、 Na ２ Oを1.00~5.00%、 K ２ It contains 0.00 to 1.40% of O, A method for manufacturing chemically strengthened glass, wherein the molten salt used in at least one of the chemical strengthening treatments satisfies the following requirements 1 and 2. Requirement 1: The molten salt contains silicic acid. Requirement 2: When the molten salt is solidified and dissolved in pure water to obtain a 9% by mass aqueous solution, the pH of the aqueous solution is 6.0 or less.

16. A method for producing chemically strengthened glass according to claim 15, wherein the chemical strengthening treatment is performed two or more times.

17. A method for producing chemically strengthened glass according to claim 15, wherein the chemical strengthening treatment is performed three or more times.

18. A method for producing chemically strengthened glass according to claim 16, wherein the chemical strengthening treatment is performed twice, and the molten salt used in the first chemical strengthening treatment satisfies requirement 1 and requirement 2.

19. A method for manufacturing chemically strengthened glass according to claim 16, wherein the chemical strengthening treatment is performed twice, and the molten salt used in the first and second chemical strengthening treatments satisfies requirements 1 and 2.

20. A method for manufacturing chemically strengthened glass according to claim 17, wherein the chemical strengthening treatment is performed three times, and the molten salt used in the first and second chemical strengthening treatments satisfies requirements 1 and 2.

21. A method for manufacturing chemically strengthened glass according to claim 17, wherein the chemical strengthening treatment is performed three times, and the molten salt used in the first, second, and third chemical strengthening treatments satisfies requirement 1 and requirement 2.

22. Li of the chemically strengthened glass ２ Regarding the O content, the LiNOx used in the first chemical strengthening treatment of the chemical strengthening treatment is... ３ A method for producing chemically strengthened glass according to claim 15 or 16, wherein the content ratio of is 75 mol% or less.

23. A method for producing chemically strengthened glass according to claim 15 or 16, wherein the molten salt satisfying requirement 1 further comprises sodium metasilicate.

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