Chemically strengthened glass, method for manufacturing chemically strengthened glass

Abstract

This invention relates to chemically strengthened glass and a method for manufacturing chemically strengthened glass. The invention provides chemically strengthened glass with excellent high-temperature and high-humidity resistance. One type of chemically strengthened glass has an average hydrogen atom concentration of 2.000 × 10⁻⁶ in a depth range of 0.75 μm to 1.25 μm measured from the surface of the chemically strengthened glass. 20 atoms / cm 3 above.

Description

Technical Field

[0001] This invention relates to chemically strengthened glass.

[0002] In addition, the present invention also relates to a method for manufacturing chemically strengthened glass. Background Technology

[0003] In recent years, protective glass has been used to improve the protection and aesthetics of display devices such as mobile phones, smartphones, and tablets. For these applications, protective glass requires excellent strength to prevent breakage caused by impacts and other factors.

[0004] In addition, the protective glass described above is sometimes used to protect solar cell modules and the like.

[0005] Previously, it was known to improve the surface strength of glass by immersing it in molten potassium nitrate salt or similar chemical strengthening treatment.

[0006] For example, Patent Document 1 discloses a method for improving the surface strength of a glass sheet by chemically strengthening it through impregnation in molten potassium nitrate salt. More specifically, it discloses a method for increasing the strength of a Li-containing glass sheet by sequentially performing chemical strengthening treatment on a Li-containing glass sheet in the order of a Na-containing molten salt and a K-containing molten salt. Furthermore, it describes the strengthening mechanism of this chemical treatment as improving the strength of the glass sheet through compressive stress generated by the exchange of alkali metals.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2017 / 170053 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] Chemically strengthened glass is sometimes used in high temperature and high humidity environments.

[0012] The inventors studied the chemically strengthened glass described in the aforementioned patent document 1 and found that it sometimes has poor resistance to high temperature and high humidity, so it is necessary to improve it.

[0013] The present invention was made in view of the above-mentioned problems, and its object is to provide a chemically strengthened glass with excellent high temperature and high humidity resistance.

[0014] In addition, the present invention aims to provide a method for manufacturing chemically strengthened glass.

[0015] means for solving problems

[0016] The inventors conducted in-depth research on the above-mentioned problems and found that by keeping the hydrogen concentration on the surface within a specified range, the high temperature and high humidity resistance was improved, thus completing the present invention.

[0017] That is, the inventors discovered that the above problems can be solved by the following configuration.

[0018] [1] A chemically strengthened glass, wherein the average hydrogen atom concentration in a depth range of 0.75 μm to 1.25 μm measured from the surface of the chemically strengthened glass is 2.000 × 10⁻⁶. 20 atoms / cm 3 above.

[0019] [2] According to the chemically strengthened glass of [1], the ratio of the hydrogen atom concentration at a depth of 1.00 μm from the surface of the chemically strengthened glass to the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface of the chemically strengthened glass is 1.490 or more.

[0020] [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 of the chemically strengthened glass to the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface of the chemically strengthened glass is 1.250 or more.

[0021] [4] The chemically strengthened glass according to any one of [1] to [3], wherein the absolute value of the slope of the hydrogen atom concentration relative to depth, calculated from the average hydrogen atom concentration in a depth range of 2.50 μm to 3.00 μm measured from the surface of the chemically strengthened glass and the hydrogen atom concentration at a depth of 0.50 μm measured from the surface of the chemically strengthened glass, is 0.600 × 10⁻⁶. 20 atoms / cm 3 Above μm.

[0022] [5] The chemically strengthened glass according to any one of [1] to [4], wherein the value obtained by subtracting the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface of the chemically strengthened glass from the hydrogen atom concentration at a depth of 0.50 μm measured from the surface of the chemically strengthened glass is 1.800 × 10⁻⁶. 20 atoms / cm 3 above.

[0023] [6] The chemically strengthened glass according to any one of [1] to [5], wherein the integral approximation of the hydrogen atom concentration in the depth range of 0.00 μm to 1.00 μm measured from the surface of the chemically strengthened glass is 15.000 × 10⁻⁶ with respect to the average hydrogen atom concentration in the depth range of 0.75 μm to 1.25 μm measured from the surface of the chemically strengthened glass. - 5 Less than cm.

[0024] [7] The chemically strengthened glass according to any one of [1] to [6], wherein the chemically strengthened glass is a microcrystalline glass.

[0025] [8] The chemically strengthened glass according to [7], wherein the chemically strengthened glass comprises one or more crystals selected from the group consisting of lithium silicate crystals, lithium aluminosilicate crystals and lithium phosphate crystals.

[0026] [9] The chemically strengthened glass according to [7] or [8], wherein the crystallinity of the chemically strengthened glass is 10% to 70%.

[0027]

[10] The chemically strengthened glass according to any one of [1] to [9], wherein, based on the molar percentage of oxides, the chemically strengthened glass comprises: 40.00% to 75.00% SiO2, 2.00% to 20.00% Al2O3, 9.00% to 40.00% Li2O, 1.00% to 8.00% Na2O, and 0.00% to 2.00% K2O.

[0028]

[11] The chemically strengthened glass as described in any one of [1] to

[10] , wherein the haze of the chemically strengthened glass after being subjected to a high temperature and high humidity resistance test for 240 hours at a temperature of 85°C and a relative humidity of 85% is less than 20 times the haze of the chemically strengthened glass before the high temperature and high humidity resistance test.

[0029]

[12] The chemically strengthened glass according to any one of [1] to

[11] , wherein the thickness of the chemically strengthened glass is 2.0 mm or less.

[0030]

[13] The chemically strengthened glass according to any one of [1] to

[12] , wherein the fracture toughness value K of the chemically strengthened glass is IC 0.82 MPa·m 1 / 2 above.

[0031]

[14] The chemically strengthened glass according to any one of [1] to

[13] , wherein the Young's modulus of the chemically strengthened glass is 84 GPa or higher.

[0032]

[15] A method for manufacturing chemically strengthened glass, comprising a method for obtaining chemically strengthened glass by performing one or more chemical strengthening treatments in which the chemically strengthened glass is brought into contact with molten salt, wherein, Based on oxide molar percentages, the chemically strengthened glass comprises: 40.00%–75.00% SiO2, 2.00%–20.00% Al2O3, 9.00%–40.00% Li2O, 1.00%–5.00% Na2O, and 0.00%–1.40% K2O. The molten salt used in at least one of the chemical strengthening processes satisfies the following necessary conditions 1 and 2. Necessary condition 1: The molten salt contains silicic acid; Necessary condition 2: When the molten salt is solidified and dissolved in pure water to prepare an aqueous solution with a concentration of 9% by mass, the pH of the aqueous solution is below 6.0.

[0033]

[16] The method for manufacturing chemically strengthened glass as described in

[15] , wherein the chemical strengthening treatment is performed more than twice.

[0034]

[17] The method for manufacturing chemically strengthened glass according to

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

[0035]

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

[15] or

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

[0036]

[19] A method for manufacturing chemically strengthened glass as described in any one of

[15] ,

[16] and

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

[0037]

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

[15] to

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

[0038]

[21] A method for manufacturing chemically strengthened glass as described in any one of

[15] to

[17] and

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

[0039]

[22] A method for manufacturing 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 in the chemical strengthening treatment to the content of Li2O in the chemically strengthened glass is 75 mol% or less.

[0040]

[23] The method for manufacturing chemically strengthened glass according to any one of

[15] to

[22] , wherein the molten salt satisfying the necessary condition 1 further comprises sodium metasilicate.

[0041] Invention Effects

[0042] According to the present invention, chemically strengthened glass with excellent high temperature and high humidity resistance can be provided.

[0043] Furthermore, according to the present invention, a method for manufacturing chemically strengthened glass can be provided. Attached Figure Description

[0044] Figure 1 To determine the fracture toughness value K using the DC-DC method IC An explanatory diagram of the sample used.

[0045] Figure 2 To illustrate the determination of fracture toughness value K using the DC-DC method IC The stress intensity factor K1 used (unit: MPa·m) 1 / 2 A graph of the K1-v curve showing the relationship between crack propagation rate v (unit: m / s) and crack propagation speed v. Detailed Implementation

[0046] The chemically strengthened glass of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. It can be implemented in any modified way without departing from the spirit of the present invention.

[0047] In this specification, "chemically strengthened glass" refers to glass that has undergone chemical strengthening treatment. Conversely, "chemically strengthened glass" refers to glass before undergoing chemical strengthening treatment.

[0048] In this specification, the glass composition of chemically strengthened glass is sometimes referred to as the matrix glass composition of chemically strengthened glass. In chemically strengthened glass, a compressive stress layer formed by ion exchange is usually formed on the glass surface; therefore, the glass composition of the portion that has not undergone ion exchange is consistent with the matrix glass composition of the chemically strengthened glass.

[0049] In this specification, the glass composition is expressed as a mole percentage based on oxides, and mole % is sometimes simply stated as %. Additionally, the "~" indicating a numerical range is used to encompass the values ​​preceding and following it as lower and upper limits.

[0050] "Substantially not contained" in the glass composition means that it is not contained except for unavoidable impurities contained in raw materials, etc., that is, it is not intentionally contained. Specifically, regarding components other than those described in the glass composition, it is preferably less than 0.1 mol%, more preferably less than 0.08 mol%, and even more preferably less than 0.05 mol%.

[0051] In this specification, "stress distribution" is a graph representing compressive stress values ​​with depth measured from the glass surface as the variable. Negative compressive stress values ​​refer to tensile stress.

[0052] In this specification, the "stress distribution" can be determined by using a scattered light photoelastic stress meter.

[0053] The method using a scattered light photoelastic stress meter allows for the measurement of stress independent of the refractive index distribution generated 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 Seisakusho Co., Ltd.

[0054] In this specification, the compressive stress layer depth refers to the depth at which the compressive stress value is zero.

[0055] In this specification, "fracture toughness value K" IC "The determination was performed using the DCDC method [Reference: MY He, MR Turner and AG Evans, Acta Metall. Mater. 43(1995)3453.]. Specifically, using..." Figure 1 The sample, as shown, and the SHIMADZU Autograph AGS-X5KN were measured as follows: Figure 2 The figure shows the stress intensity factor K1 (unit: MPa·m). 1 / 2 The K1-v curve relating the stress intensity factor K1 to the crack propagation rate v (unit: m / s) was used to extrapolate the obtained Region III data using a linear regression, and the stress intensity factor K1 of 0.1 m / s was taken as the fracture toughness value K. IC .

[0056] In this specification, "high temperature and high humidity resistance" refers to the fact that when chemically strengthened glass is left to stand for 240 hours at 85°C and 85% relative humidity, the haze does not easily increase. The specific evaluation method for high temperature and high humidity resistance is described below.

[0057] Chemically strengthened glass

[0058] The chemically strengthened glass of this invention has an average hydrogen atom concentration of 2.000 × 10⁻⁶ in a depth range of 0.75 μm to 1.25 μm from the surface. 20 atoms / cm 3 above.

[0059] The mechanism by which the chemically strengthened glass of the present invention exhibits excellent high-temperature and high-humidity resistance may not be determined, but the inventors speculate as follows.

[0060] According to the research of the inventors, it has been found that under high temperature and high humidity conditions, due to the reaction between carbon dioxide contained in the air, water in the environment, and alkaline components contained in chemically strengthened glass, white precipitates sometimes form on the surface of chemically strengthened glass.

[0061] In the chemically strengthened glass of this invention, the concentration of hydrogen atoms near the surface is relatively high. It is believed that with a high concentration of hydrogen atoms near the surface, the interatomic distance between the atoms constituting the glass near the surface tends to be shorter due to the small ionic radius of hydrogen atoms. Therefore, even when moisture adheres to the surface of the chemically strengthened glass under high temperature and humidity conditions, alkali components are less likely to dissolve to the surface of the chemically strengthened glass, resulting in a less pronounced increase in haze.

[0062] The chemically strengthened glass of the present invention will now be described.

[0063] [Hydrogen atom concentration]

[0064] The parameters related to hydrogen atom concentration in the chemically strengthened glass of the present invention can be obtained by using the following methods to obtain the hydrogen concentration distribution and by analyzing it through various methods.

[0065] In determining the hydrogen concentration distribution in chemically strengthened glass, secondary ion mass spectrometry (SIMS) was used. It should be noted that SIMS allows analysis to be performed simultaneously with surface cutting via ion irradiation, thus enabling the determination of hydrogen concentration at specified depths.

[0066] In this invention, the hydrogen concentration distribution is determined by measuring the hydrogen concentration in a standard sample with a known hydrogen concentration. 1 H - / 30 Si- The depth-direction distribution of the intensity ratio and the chemically strengthened glass being measured. 1 H - / 30 Si - The intensity ratio is determined by comparing the distribution of intensity ratios along the depth direction.

[0067] The following is a detailed explanation of the method for obtaining the hydrogen concentration distribution.

[0068] The standard sample with the known hydrogen concentration was prepared by the following method.

[0069] First, a portion of the chemically strengthened glass to be measured is cut out.

[0070] The area exceeding 50 μm from the cut surface of the chemically strengthened glass is removed by grinding or chemical etching. This removal process is performed on both sides of the chemically strengthened glass. That is, the total removal thickness on both sides is 100 μm or more. The chemically strengthened glass with the surface removed as described above is used as a standard sample.

[0071] The obtained standard sample was measured using infrared spectroscopy (IR), and the 3550 cm⁻¹ of the obtained IR spectrum was determined. -1 The absorbance height A of the nearby peak 3550 and 4000cm -1 absorbance height A 4000 (Baseline). Next, the thickness d (cm) of the standard sample was measured using a micrometer and other plate thickness measuring instruments. Then, referring to reference A, the actual infrared absorption coefficient ε of H₂O in the glass was calculated. pract (L / (mol·cm)) is set to 75, and the hydrogen concentration of the standard sample is calculated using equation (II) (converted to H2O, mol / L).

[0072] Hydrogen concentration of standard sample = (A 3550 -A 4000 ) / (ε pract ·d)…Formula (II)

[0073] Document A: S. lievski et al., Glasstch. Ber. Glass Sci. Technol., 73(2000)39.

[0074] 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 measured sequentially to obtain the results. 1 H - and 30 Si -The intensity distribution along the depth direction. Then, using... 1 H - Distribution divided by 30 Si - Distribution, obtained 1 H - / 30 Si - The distribution of intensity ratio along the depth direction.

[0075] Next, based on the standard sample 1 H - / 30 Si - The depth-direction distribution of the intensity ratio was calculated, and the average intensity ratio was calculated for the range from 1 μm to 2 μm. 1 H - / 30 Si - The intensity ratio was determined, and a calibration curve was constructed between this value and the hydrogen concentration, passing through the origin. This yielded a calibration curve for a standard sample at a given level. Using this calibration curve, the vertical axis representing the distribution of the chemically strengthened glass being measured was plotted. 1 H - / 30 Si - The intensity ratio is converted into hydrogen concentration. Through the above steps, the hydrogen concentration distribution of the chemically strengthened glass being measured is obtained. It should be noted that the measurement conditions for SIMS and IR are as follows.

[0076] (SIMS measurement conditions)

[0077] The measurement conditions for SIMS in this invention are as follows.

[0078] Device: ADEPT 1010 manufactured by ULVAC-PHI

[0079] Primary ion type: Cs +

[0080] Accelerating voltage for primary ions: 5kV

[0081] Primary ion current: 500 nA

[0082] The incident angle of the primary ions is 60° relative to the normal to the sample surface.

[0083] Primary ion grating size: 300×300μm 2

[0084] Polarity of secondary ions: negative

[0085] Detection area for secondary ions: 60 × 60 μm 2 (4% of the grating size for primary ions)

[0086] ESA Input Lens: 0

[0087] Use of neutralization guns: Yes

[0088] In addition, the sputtering rate of the primary ions was measured beforehand, and the sputtering time was converted into depth. Specifically, the depth of the analytical pit was measured using a stylus-type surface shape analyzer (Dektak 150 manufactured by Veeco), and the sputtering rate of the primary ions was determined.

[0089] It should be noted that, 1 H - The optimal value of the field axis potential during testing may vary depending on the device, so the tester should carefully set the value to adequately remove background.

[0090] (IR measurement conditions)

[0091] The IR measurement conditions in this invention are as follows.

[0092] Device: Nic-plan / Nicolet 6700 manufactured by Thermo Fisher Scientific

[0093] Resolution: 4cm -1

[0094] Total number of sums: 16

[0095] Detector: TGS detector

[0096] Through the above steps, the hydrogen concentration distribution along the depth direction, measured from the outermost surface of the chemically strengthened glass, is obtained. The above hydrogen concentration distribution is plotted with depth (μm) on the horizontal axis and hydrogen concentration (atoms / cm³) on the vertical axis. 3 The distribution of ).

[0097] In this specification, the average hydrogen atom concentration within a depth range of d1μm to d2μm from the surface refers to the value obtained by arithmetic averaging of the hydrogen concentrations at measurement points within the depth range of d1μm to d2μm from the surface.

[0098] Furthermore, in this specification, the hydrogen atom concentration at a depth of d3μm, measured from the surface, refers to the value obtained by linear interpolation from the measurement points closest to and second closest to d3μm. It should be noted that if a measurement point with a hydrogen concentration of d3μm exists, the hydrogen concentration at that measurement point is taken as the hydrogen concentration at d3μm.

[0099] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (hereinafter also referred to as "A") in the depth range of 0.25 μm to 0.75 μm from the surface is... 0.5μm The preferred value is 2.500×10⁻⁶. 20 atoms / cm 3 The above, more preferably 3.000×10 20 atoms / cm 3 The above is further preferred to be 4.000×10 20 atoms / cm 3 above. A 0.5μm In most cases, it is 100,000 × 10 20 atoms / cm 3 The preferred value is 50.000 × 10 20 atoms / cm 3 Hereinafter, 30.000×10 is more preferred. 20 atoms / cm 3 Hereinafter, 10.000×10 is further preferred. 20 atoms / cm 3 the following.

[0100] The average hydrogen atom concentration (hereinafter also referred to as "A") of the chemically strengthened glass of the present invention in the depth range of 0.75 μm to 1.25 μm from the surface. 1.0μm ") is 2.000×10 20 atoms / cm 3 Above, A 1.0μm Preferably 2.500×10 20 atoms / cm 3 The above, more preferably 3.000×10 20 atoms / cm 3 above. A 1.0μm In most cases, it is 50,000 × 10 20 atoms / cm 3 The preferred value is 30.000 × 10. 20 atoms / cm 3 Hereinafter, 15.000 × 10 is more preferred. 20 atoms / cm 3 Hereinafter, 10.000×10 is further preferred. 20 atoms / cm 3 the following.

[0101] Furthermore, in the chemically strengthened glass of the present invention, the average hydrogen atom concentration (hereinafter also referred to as "A") in the depth range of 2.50 μm to 3.00 μm measured from the surface is... 2.75μm The preferred value is 0.400×10⁻⁶. 20atoms / cm 3 The above, more preferably 0.600×10 20 atoms / cm 3 The above is further optimized to be 0.900×10 20 atoms / cm 3 above. A 2.75μm In most cases, it is 30,000 × 10 20 atoms / cm 3 The preferred value is 20.000 × 10. 20 atoms / cm 3 Hereinafter, 10.000×10 is more preferred. 20 atoms / cm 3 Hereinafter, 5.000×10 is further preferred. 20 atoms / cm 3 the following.

[0102] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (hereinafter also referred to as "C") at a depth of 0.05 μm from the surface is... 0.05μm The preferred value is 2.500×10⁻⁶. 20 atoms / cm 3 The above, more preferably 3.000×10 20 atoms / cm 3 The above is further preferred to be 4.000×10 20 atoms / cm 3 That's all. (C) 0.05μm In most cases, it is 100,000 × 10 20 atoms / cm 3 The preferred value is 50.000 × 10 20 atoms / cm 3 Hereinafter, 30.000×10 is more preferred. 20 atoms / cm 3 Hereinafter, 15.000×10 is further preferred. 20 atoms / cm 3 the following.

[0103] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (hereinafter also referred to as "C") at a depth of 0.50 μm from the surface is... 0.5μm The preferred value is 2.000×10⁻⁶. 20 atoms / cm 3 The above is preferred, and more preferably is 2.500×10 20 atoms / cm 3 The above is further preferred to be 3.000×10 20 atoms / cm 3 The above is particularly preferred to be 4.000×10.20 atoms / cm 3 That's all. (C) 0.5μm In most cases, it is 100,000 × 10 20 atoms / cm 3 The preferred value is 50.000 × 10 20 atoms / cm 3 Hereinafter, 30.000×10 is more preferred. 20 atoms / cm 3 Hereinafter, 15.000×10 is further preferred. 20 atoms / cm 3 the following.

[0104] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (hereinafter also referred to as "C") at a depth of 1.00 μm measured from the surface is... 1.0μm The preferred value is 2.000×10⁻⁶. 20 atoms / cm 3 The above is preferred, and more preferably is 2.250×10 20 atoms / cm 3 The above is further preferred to be 2.500×10 20 atoms / cm 3 That's all. (C) 1.0μm In most cases, it is 100,000 × 10 20 atoms / cm 3 The preferred value is 50.000 × 10 20 atoms / cm 3 Hereinafter, 30.000×10 is more preferred. 20 atoms / cm 3 Hereinafter, 10.000×10 is further preferred. 20 atoms / cm 3 the following.

[0105] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (hereinafter also referred to as "C") at a depth of 1.50 μm measured from the surface is... 1.5μm The preferred value is 1.650×10⁻⁶. 20 atoms / cm 3 The above, more preferably 1.700×10 20 atoms / cm 3 The above is further preferred to be 2.000×10 20 atoms / cm 3 That's all. (C) 0.5μm In most cases, it is 50,000 × 10 20 atoms / cm 3 The preferred value is 30.000 × 10. 20 atoms / cm3 Hereinafter, 15.000 × 10 is more preferred. 20 atoms / cm 3 the following.

[0106] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (C) at a depth of 0.05 μm measured from the surface is... 0.05μm The average hydrogen atom concentration relative to the depth range of 2.50 μm to 3.00 μm from the surface (A) 2.75μm The ratio of (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. Furthermore, the above ratio (C) 0.05μm / A 2.75μm Preferably, it is 18.000 or less, more preferably 14.000 or less, and even more preferably 11.000 or less.

[0107] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (C0) at a depth of 0.50 μm measured from the surface is... 0.5μm The average hydrogen atom concentration relative to the depth range of 2.50 μm to 3.00 μm from the surface (A) 2.75μm The ratio of (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. Furthermore, the above ratio (C) 0.5μm / A 2.75μm In most cases, it is 12.000 or less, preferably 10.000 or less, and more preferably 8.000 or less.

[0108] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (C) at a depth of 1.00 μm measured from the surface is... 1.0μm The average hydrogen atom concentration relative to the depth range of 2.50 μm to 3.00 μm from the surface (A) 2.75μm The ratio of (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. Furthermore, the above ratio (C) 1.0μm / A 2.75μm In most cases, it is 10.000 or less, preferably 8.000 or less, and more preferably 6.000 or less.

[0109] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (C) at a depth of 1.50 μm measured from the surface is... 1.5μmThe average hydrogen atom concentration relative to the depth range of 2.50 μm to 3.00 μm from the surface (A) 2.75μm The ratio of (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. Furthermore, the above ratio (C) 1.5μm / A 2.75μm In most cases, it is 10.000 or less, preferably 6.000 or less, and more preferably 4.000 or less.

[0110] Furthermore, in the chemically strengthened glass of the present invention, the hydrogen atom concentration (C0) at a depth of 0.50 μm measured from the surface is... 0.5μm Subtract the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface (A) 2.75μm The value obtained (C) 0.5μm -A 2.75μm The preferred value is 1.500×10 20 atoms / cm 3 The above, more preferably 1.800×10 20 atoms / cm 3 The above is further preferred to be 1.900×10 20 atoms / cm 3 That's all. Additionally, the above value (C) 0.5μm -A 2.75μm In most cases, it is 15.000 × 10 20 atoms / cm 3 The preferred value is 10.000 × 10. 20 atoms / cm 3 Hereinafter, 8.000×10 is more preferred. 20 atoms / cm 3 the following.

[0111] Hereinafter, an integral approximation of the hydrogen atom concentration in the chemically strengthened glass of the present invention, measured from the surface in the depth range of 0.00 μm to 1.00 μm (hereinafter also referred to as "I"), is obtained. 1.0μm The method described is as follows: First, for each measurement point, the product of the distance from each measurement point to the measurement point with a depth smaller than that measurement point and the hydrogen atom concentration at that measurement point is calculated. It should be noted that for the measurement point closest to 0.00 μm, the product of the distance from 0.00 μm to that measurement point and the hydrogen atom concentration at that measurement point is calculated.

[0112] For the measurement points within a depth range of 0.00 μm to 1.00 μm from the surface, accumulate the product calculated above to obtain the above I. 1.0μm .

[0113] I 1.0μm Preferably 31.000×10 15 atoms / cm 2 The above, more preferably 35.000×10 15 atoms / cm 2 The above is further preferred to be 40.000×10 15 atoms / cm 2 That's all. Additionally, I 1.0μm In most cases, it is 150,000 × 10 15 atoms / cm 2 The preferred value is 120.000 × 10 15 atoms / cm 2 Hereinafter, 100.000 × 10 is more preferred. 15 atoms / cm 2 the following.

[0114] Furthermore, in the chemically strengthened glass of the present invention, the integral approximation of the hydrogen concentration in the depth range of 0.00 μm to 0.1 μm measured from the surface (hereinafter also referred to as "I") is... 0.1μm The preferred value is 5.500×10⁻⁶. 15 atoms / cm 2 The above, more preferably 6.000×10 15 atoms / cm 2 The above is further preferred to be 6.300×10 15 atoms / cm 2 That's all. Additionally, I 0.1μm In most cases, it is 30,000 × 10 15 atoms / cm 2 The preferred value is 20.000 × 10. 15 atoms / cm 2 Hereinafter, 15.000 × 10 is more preferred. 15 atoms / cm 2 the following.

[0115] I 0.1μm Apart from the difference in scope, it is similar to the above I 1.0μm Similarly, find the answer.

[0116] Furthermore, in the chemically strengthened glass of the present invention, the integral approximation of the hydrogen concentration in the depth range of 0.00 μm to 1.00 μm measured from the surface (I... 1.0μmThe average hydrogen atom concentration relative to the depth range of 0.75 μm to 1.25 μm from the surface (A) 1.0μm The ratio of (I) 1.0μm / A 1.0μm The preferred value is 15.000 × 10 -5 Below 1 cm, more preferably 14.500 × 10 cm. - 5 Below 1 cm, more preferably 13.500 × 10 cm. -5 Below cm. The above ratio (I) 1.0μm / A 1.0μm In most cases, it is 2.000 × 10 -5 cm or larger, preferably 5.000 × 10 cm -5 cm or more, preferably 8.000 × 10 cm. -5 cm or more.

[0117] The average hydrogen atom concentration (A) within a depth range of 2.50 μm to 3.00 μm from the surface. 2.75μm ) and the hydrogen atom concentration (C) at a depth of 0.50 μm measured from the surface. 0.5μm The absolute value of the slope of the calculated hydrogen atom concentration relative to depth is preferably 0.600 × 10⁻⁶. 20 atoms / cm 3 μm or larger, more preferably 0.700 × 10 μm 20 atoms / cm 3 μm or larger, more preferably 0.800 × 10⁻⁶ μm or larger. 20 atoms / cm 3 • μm and above. The absolute value of the aforementioned slope is in most cases 10.000 × 10⁻⁶. 20 atoms / cm 3 Below μm. Here, the slope S of the hydrogen atom concentration relative to depth is calculated by the following formula.

[0118]

[0119] [Compressive stress]

[0120] The chemically strengthened glass of the present invention, in most cases, has a compressive stress layer that acts on the surface side compressive stress. Hereinafter, preferred parameters regarding the compressive stress will be described.

[0121] From the viewpoint that the chemically strengthened glass of the present invention is not prone to breakage even under greater impact when it collides with other objects, the compressive stress (CS) at a depth of 50 μm in the chemically strengthened glass of the present invention is [missing information]. 50Preferably, the pressure is 30 MPa or more, more preferably 40 MPa or more, and even more preferably 50 MPa or more. Furthermore, from the viewpoint of not exceeding the CT limit of glass, the CS of the chemically strengthened glass of the present invention... 50 In most cases, the pressure is 350 MPa or less, preferably 300 MPa or less, more preferably 250 MPa or less, and even more preferably 200 MPa or less.

[0122] From the viewpoint that the chemically strengthened glass of the present invention is not prone to breakage even under greater impact when it collides with other objects, the compressive stress (CS) at a depth of 90 μm in the chemically strengthened glass of the present invention is [missing information]. 90 Preferably, the pressure is -10 MPa or higher, more preferably 0 MPa or higher, and even more preferably 5 MPa or higher. Furthermore, from the viewpoint of not exceeding the CT limit of glass, the CS of the chemically strengthened glass of the present invention... 90 In most cases, the pressure is 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.

[0123] The compressive stress at each of the aforementioned depths can be determined by using the method described above, and then calculated from the stress distribution.

[0124] 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.

[0125] Furthermore, regarding the compressive stress layer depth (DOC) of the chemically strengthened glass of the present invention, the value of the compressive stress layer depth (DOC) is preferably 0.16 times or more than the thickness of the chemically strengthened glass of the present invention, more preferably 0.17 times or more. Herein, the units for the compressive stress layer depth (DOC) and the unit for the thickness of the chemically strengthened glass are μm. That is, the value obtained by dividing the DOC (unit: μm) of the chemically strengthened glass of the present invention by the thickness (unit: μm) is preferably 0.16 times or more, more preferably 0.17 times or more.

[0126] The compressive stress layer depth (DOC) is in most cases less than 0.25 times the thickness of the chemically strengthened glass of this invention.

[0127] [Tensile stress]

[0128] The chemically strengthened glass of the present invention has a compressive stress layer on its surface in most cases, in which case a tensile stress that balances it acts inside the chemically strengthened glass.

[0129] The preferred parameters related to tensile stress are explained below.

[0130] The maximum tensile stress (CT) of the chemically strengthened glass of this invention Max Preferably, the pressure is 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 In most cases, the pressure is below 200 MPa, preferably below 175 MPa, more preferably below 150 MPa, and even more preferably below 130 MPa.

[0131] CT Max Determined by stress distribution, it typically plays a role in the center of the plate thickness.

[0132] The average tensile stress (CT) of the chemically strengthened glass of this invention ave Preferably, the pressure is 10 MPa or more, more preferably 20 MPa or more, and even more preferably 30 MPa or more. Furthermore, the CT of the chemically strengthened glass of the present invention... ave In most cases, the pressure is 150 MPa or less, preferably 120 MPa or less, more preferably 100 MPa or less, and even more preferably 90 MPa or less.

[0133] The average value of tensile stress is obtained by dividing the integral value of the tensile stress in the thickness direction of the plate by the length of the tensile stress region in the region showing the depth of tensile stress in the stress distribution.

[0134] The integral value of tensile stress (ICT) of the chemically strengthened glass of the present invention is, in most cases, 40,000 Pa·m or less, preferably 35,000 Pa·m or less, and more preferably 30,000 Pa·m or less. There is no particular limitation on the lower limit of ICT, but in most cases it is 8,000 Pa·m or more, preferably 10,000 Pa·m or more.

[0135] ICT is obtained by integrating the tensile stress over a region where the stress distribution is deep enough to show the tensile stress.

[0136] [Plate thickness]

[0137] The thickness of the chemically strengthened glass of the present invention can be appropriately adjusted according to the application, but in most cases it is 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 in most cases 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 can also be 0.7 mm or less.

[0138] [physical properties]

[0139] 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 limitation on the upper limit of the Young's modulus, typically it is 120 GPa or lower.

[0140] The Young's modulus of chemically strengthened glass is usually the same as that of chemically strengthened glass.

[0141] The fracture toughness value K of the chemically strengthened glass of this invention IC The preferred value is 0.80 MPa·m 1 / 2 The above is more preferably 0.82 MPa·m 1 / 2 The above is further preferably 0.85 MPa·m 1 / 2 The above, especially preferred, is 0.90 MPa·m 1 / 2 The above is preferably in the following order: 1.00 MPa·m 1 / 2 Above, 1.10 MPa·m 1 / 2 The above. Fracture toughness value K IC There is no specific upper limit, typically 1.60 MPa·m. 1 / 2 the following.

[0142] Fracture toughness value K of chemically strengthened glass IC Typically compared with the fracture toughness value K of chemically strengthened glass. IC Consistent.

[0143] [High Temperature and High Humidity Resistance Test]

[0144] The chemically strengthened glass of the present invention exhibits excellent high-temperature and high-humidity resistance. Specifically, the haze of the chemically strengthened glass of the present invention after undergoing a high-temperature and high-humidity resistance test for 240 hours at a relative humidity of 85% is preferably less than 60 times, more preferably less than 20 times, compared to the haze before the high-temperature and high-humidity resistance test.

[0145] The haze before and after the high temperature and high humidity resistance test was measured according to the method described in the examples below.

[0146] In most cases, the haze level after the high temperature and humidity resistance test is more than double that before the test.

[0147] [composition]

[0148] The chemically strengthened glass of the present invention is obtained by chemically strengthening glass (glass for chemical strengthening) before chemical strengthening.

[0149] The composition of chemically strengthened glass is generally consistent with the composition at the center of its thickness. That is, the preferred composition at the center of the thickness of chemically strengthened glass is generally consistent with the preferred composition of chemically strengthened glass.

[0150] Based on the molar percentage of oxides, the chemically strengthened glass preferably contains: 40.00%–75.00% SiO2, 2.00%–20.00% Al2O3, 9.00%–40.00% Li2O, 1.00%–8.00% Na2O, and 0.00%–2.00% K2O.

[0151] Based on the molar percentage of oxides, the chemically strengthened glass preferably contains: 40.00%–75.00% SiO2, 2.00%–20.00% Al2O3, 0.00%–5.00% P2O5, 9.00%–40.00% Li2O, 1.00%–8.00% Na2O, 0.00%–2.00% K2O, 0.00%–10.00% MgO, 0.00%–5.00% CaO, and 0.00%–5.00% ZrO2.

[0152] Further optimized compositions of chemically strengthened glass and methods for manufacturing chemically strengthened glass will be detailed later.

[0153] Furthermore, the chemically strengthened glass is preferably a glass crystal. When the chemically strengthened glass, which is a glass crystal, is chemically strengthened, a chemically strengthened glass, which is a glass crystal, is obtained. That is, the chemically strengthened glass of the present invention is preferably a glass crystal.

[0154] It should be noted that the crystals contained in the chemically strengthened glass are also included in the chemically strengthened glass itself, and the preferred method for the crystals contained in the chemically strengthened glass is the same as that for the chemically strengthened glass. The preferred method for the case where the chemically strengthened glass is a glass-ceramic is the same as that for the case where the chemically strengthened glass is a glass-ceramic, therefore, the description is omitted.

[0155] <Manufacturing Methods of Chemically Strengthened Glass>

[0156] The method for manufacturing chemically strengthened glass according to the present invention is to obtain chemically strengthened glass by performing a chemical strengthening treatment in which the chemically strengthened glass is brought into contact with molten salt once or more.

[0157] Here, the molten salt used in at least one of the above-mentioned chemical enhancement treatments satisfies the following necessary conditions 1 and 2.

[0158] Necessary condition 1: The above molten salt contains silicic acid.

[0159] Necessary condition 2: When the above molten salt is solidified and dissolved in pure water to prepare an aqueous solution with a concentration of 9% by mass, the pH of the aqueous solution is below 6.0.

[0160] In addition, based on the molar percentage of oxides, the chemically strengthened glass preferably contains: 40.00% to 75.00% SiO2, 2.00% to 20.00% Al2O3, 9.00% to 40.00% Li2O, 1.00% to 5.00% Na2O, and 0.00% to 1.40% K2O.

[0161] The method for manufacturing the chemically strengthened glass of the present invention will be described below.

[0162] [Chemical fortification treatment]

[0163] In the method for manufacturing chemically strengthened glass of the present invention, a chemical strengthening treatment is performed once or more, in which the chemically strengthened glass is brought into contact with molten salt.

[0164] It should be noted that in the above chemical strengthening treatment, the molten salt used in at least one chemical strengthening treatment satisfies the above-mentioned necessary conditions 1 and 2. Hereinafter, the molten salt that satisfies the above-mentioned necessary conditions 1 and 2 will also be referred to as the "specific molten salt".

[0165] When chemically strengthened glass is immersed in molten salt, the metal ions with small ionic radii (typically Na or Li ions) in the chemically strengthened glass are replaced by metal ions with large ionic radii (typically K ions relative to Na ions, and Na or K ions relative to Li ions).

[0166] The following is an explanation of chemical enhancement treatment.

[0167] (molten salt)

[0168] The molten salt used in the method for manufacturing chemically strengthened glass of the present invention will be described.

[0169] First, the following describes a specific molten salt that satisfies the above-mentioned necessary conditions 1 and 2.

[0170] The specific molten salt contains silica (necessary condition 1).

[0171] In addition, when a specific molten salt is solidified and dissolved in pure water to prepare an aqueous solution with a concentration of 9% by mass, the pH of the aqueous solution is below 6.0 (necessary condition 2).

[0172] In this specification, silicic acid refers to a compound containing 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), disilicic acid (2SiO2·H2O), orthosilicic acid (SiO2·2H2O), pyrosilicic acid (2SiO2·3H2O), and silica gel, etc.

[0173] In this invention, silica gel is preferably included as the silicic acid.

[0174] Silica gel is a compound represented by the chemical formula SiO2·mH2O (where m is a real number from 0.1 to 1). In silica gel, in most cases, non-porous primary particles with silanol groups on the surface aggregate to form secondary particles with tiny porous structures.

[0175] The silanol groups in silicic acid (preferably silica gel) interact with alkali ions (e.g., Li, Na, and K ions) present in a specific molten salt, releasing hydrogen ions. When the released hydrogen ions are present in the specific molten salt, they can exchange with Li and Na ions contained in the chemically strengthened glass, thereby introducing hydrogen into the chemically strengthened glass. Furthermore, when the specific molten salt contains silicic acid (preferably silica gel), the OH groups in the specific molten salt... - The ions undergo a dehydration reaction with the silanol groups in silicic acid, thereby increasing the amount of hydrogen ions in a specific molten salt.

[0176] Based on the above principle, it is believed that silicic acid lowers the pH of aqueous solutions that cause specific molten salts to solidify and dissolve in pure water. It should be noted that the principle of pH lowering is not limited to this and can be explained by other principles.

[0177] It is believed that when the molten salt meets necessary condition 2, a large amount of hydrogen ions are released, making it easy to introduce hydrogen through chemical strengthening. Therefore, it is believed that the method for manufacturing chemically strengthened glass according to the present invention using the specific molten salt described above can obtain chemically strengthened glass that meets the necessary condition of average hydrogen concentration described above.

[0178] It should be noted that the pH measurement in condition 2 above was performed using a pH meter (9625-D71 manufactured by Horiba Seisakusho). Additionally, the measurement temperature was set to 25°C.

[0179] The content of silicic acid in a particular molten salt is not particularly limited as long as the specific molten salt meets the above-mentioned necessary conditions 1 and 2. The content of silicic acid relative to the mass of the components other than silicic acid in the specific molten salt 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.

[0180] In addition, relative to the mass of the components other than silicic acid in a specific molten salt, the content of silicic acid 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.

[0181] The specific molten salt preferably comprises 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 can be used alone or in combination.

[0182] The specific molten salt preferably contains nitrates, 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 is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to the total amount of components other than silicic acid. In the specific molten salt, the nitrate content may be 100% by mass, relative to the total amount of components other than silicic acid.

[0183] Furthermore, the ratio of the LiNO3 content (mol%) of the specific molten salt to the Li2O content (mol%) of the chemically strengthened glass described in detail later is preferably 75 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. The above ratio is also preferably 0 mol% or more.

[0184] A specific molten salt may contain the aforementioned metal salts and components other than silica (other components).

[0185] Other components include heteroanionic compounds. Heteroanionic compounds are compounds that contain anions of a different species than the anions that constitute the molten salt. By including heteroanionic compounds in the molten salt, the heteroanions in the molten salt react with Li ions, thereby adsorbing Li ions from the molten salt.

[0186] Examples of heteroionic anionic compounds include, for example, heteroionic sodium and heteroionic potassium. Examples of heteroionic sodium compounds include, for example, sodium metasilicate, sodium orthosilicate, sodium sesquisilicate, sodium phosphate, and sodium carbonate. Examples of heteroionic potassium compounds include, for example, potassium metasilicate, potassium phosphate, and potassium carbonate. One or more of these compounds may be used, or a combination of two or more may be used. Sodium metasilicate and potassium metasilicate exhibit particularly high lithium adsorption effects and are therefore preferred. Specifically, the molten salt preferably further comprises at least one selected from the group consisting of sodium metasilicate and potassium metasilicate, and more preferably, sodium metasilicate.

[0187] In the method for manufacturing chemically strengthened glass of the present invention, chemical strengthening treatment using molten salts other than specific molten salts can be performed. Hereinafter, molten salts other than specific molten salts will also be referred to as "other molten salts".

[0188] Other molten salts, except that they do not contain silica, are preferably in the same manner as the specific molten salts described above, and therefore their descriptions are omitted.

[0189] (Number of processing times)

[0190] In the method for manufacturing chemically strengthened glass of the present invention, one or more chemical strengthening treatments are performed.

[0191] The number of chemical enhancement treatments can be one, two, or even three times. In most cases, the number of chemical enhancement treatments is five or fewer.

[0192] It should be noted that the number of chemical strengthening treatments refers to the number of times chemical strengthening treatments are performed using molten salts with different compositions.

[0193] In the case of a single chemical strengthening treatment, the specific molten salt described above is used in that chemical strengthening treatment.

[0194] In the case of performing multiple chemical strengthening treatments, the specific molten salt described above is used in any one or more of the chemical strengthening treatments. In the case of performing multiple chemical strengthening treatments, it is preferable that the specific molten salt is used in two or more chemical strengthening treatments, and more preferably in all of the chemical strengthening treatments.

[0195] For example, in the case of performing three chemical strengthening treatments, it is preferable to use the specific molten salt described above in the first and second chemical strengthening treatments. In other words, it is preferable to perform three chemical strengthening treatments, and the molten salt used in the first and second chemical strengthening treatments satisfies the aforementioned necessary condition 1 and the aforementioned necessary condition 2.

[0196] Furthermore, when performing three chemical strengthening treatments, it is preferable to use the specific molten salt described above in the first, second, and third chemical strengthening treatments. In other words, it is preferable to perform three chemical strengthening treatments, and the molten salt used in the first, second, and third chemical strengthening treatments satisfies the aforementioned necessary condition 1 and the aforementioned necessary condition 2.

[0197] Furthermore, in the case of multiple chemical strengthening treatments, 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 (described in detail later) is preferably 75 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. The above ratio is also preferably 0 mol% or more.

[0198] (Processing conditions)

[0199] 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. It should be noted that the temperature of the chemical strengthening treatment refers to the temperature at which the molten salt for chemically strengthening glass is impregnated.

[0200] The temperature for each chemical strengthening treatment is preferably below 500°C, and more preferably below 470°C.

[0201] In the method for manufacturing chemically strengthened glass according to the present invention, the time for 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 time for each chemical strengthening treatment is in most cases 720 minutes or less, preferably 600 minutes or less, more preferably 420 minutes or less, and even more preferably 360 minutes or less.

[0202] From the viewpoint of obtaining a more preferred embodiment of the chemically strengthened glass of the present invention, the ratio of the total time of the chemical strengthening treatment using the aforementioned specific molten salt to the total time of the chemical strengthening treatment performed in the manufacturing method of the chemically strengthened glass of the present invention is preferably 0.65 or more, more preferably 0.80 or more, and even more preferably 0.90 or more. The above ratio may also be 1.00.

[0203] Chemically strengthened glass

[0204] (composition)

[0205] The composition of the chemically strengthened glass in the method for manufacturing the 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 "matrix glass composition".

[0206] Based on the molar percentage of oxides, the composition (matrix glass composition) of the chemically strengthened glass preferably contains: 40.00% to 75.00% SiO2, 2.00% to 20.00% Al2O3, 9.00% to 40.00% Li2O, 1.00% to 8.00% Na2O, and 0.00% to 2.00% K2O.

[0207] In addition, the matrix glass composition, based on the molar percentage of oxides, preferably contains: 40.00% to 75.00% SiO2, 2.00% to 20.00% Al2O3, 9.00% to 40.00% Li2O, 1.00% to 5.00% Na2O, and 0.00% to 1.40% K2O.

[0208] Based on the molar percentage of oxides, the preferred composition (matrix glass composition) of the chemically strengthened glass of the present invention more preferably contains: 40.00% to 75.00% SiO2, 2.00% to 20.00% Al2O3, 0.00% to 5.00% P2O5, 9.00% to 40.00% Li2O, 1.00% to 8.00% Na2O, 0.00% to 2.00% K2O, 0.00% to 10.00% MgO, 0.00% to 5.00% CaO, and 0.00% to 5.00% ZrO2.

[0209] The following describes the components contained in the matrix glass.

[0210] SiO2 is a component that makes up the glass network. Additionally, it improves chemical durability and reduces the formation of cracks when the glass surface is damaged.

[0211] To improve chemical durability, the SiO2 content is more preferably 42.00% or more, further preferably 45.00% or more, and particularly preferably 48.00% or more. On the other hand, from the viewpoint of improving meltability, the SiO2 content is more preferably 74.00% or less, further preferably 72.00% or less, and particularly preferably 70.00% or less.

[0212] Al₂O₃ is a component that improves ion exchange performance during chemical strengthening and increases the surface compressive stress after strengthening. Additionally, it helps in the formation of crystals containing Al and Li.

[0213] From the viewpoint of achieving the aforementioned effects, the Al2O3 content is more preferably 3.00% or more, further preferably 3.50% or more, particularly preferably 4.00% or more, and most preferably 4.05% or more. On the other hand, sometimes it is required that crystals do not easily grow during melting, that devitrification defects are not easily generated, thereby making the yield easier to increase, and that the high-temperature viscosity of the glass is reduced so that it is easy to melt. From these viewpoints, the Al2O3 content is more preferably 18.00% or less, further preferably 15.00% or less, and 12.00% or less in the following order.

[0214] Both SiO2 and Al2O3 are 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.

[0215] Furthermore, both SiO2 and Al2O3 tend to increase the melting temperature of glass. Therefore, in order to facilitate melting, the total content of SiO2 and Al2O3 is preferably 80.00% or less, more preferably 78.00% or less.

[0216] Li₂O is an ion-exchange component that improves the melt permeability of glass. By containing Li₂O in the glass, Li ions on the glass surface exchange with external Na ions, introducing Na ions into the glass interior. Furthermore, by utilizing the method of exchanging the introduced Na ions with external K ions, a stress distribution with high surface compressive stress and a thick compressive stress layer is easily obtained. In addition, by including Li₂O within the aforementioned range, microcrystalline glass is easily obtained during specific heat treatments. From the above perspective, the Li₂O content is more preferably 9.05% or more, and even more preferably 10.00% or more.

[0217] On the other hand, from the viewpoint of reducing the crystal growth rate in glass forming and minimizing the quality degradation caused by devitrification, the Li2O content is more preferably 38.00% or less, and even more preferably 36.00% or less.

[0218] Na₂O and K₂O are components that improve the meltability of glass and reduce the crystal growth rate during glass forming. Additionally, a small amount is preferred to improve ion exchange performance.

[0219] Na₂O is a component capable of ion exchange during chemical strengthening treatment using potassium salts, and it also reduces the viscosity of the glass. To achieve these effects, the Na₂O content is preferably 1.00% or more, 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 (Na₂CS) during strengthening treatment using sodium salts, the Na₂O content is more preferably 7.00% or less, further preferably 6.00% or less, and particularly preferably 5.00% or less.

[0220] K2O is a component that suppresses devitrification by inhibiting the rise of devitrification temperature and thus inhibits devitrification, and improves ion exchange performance. The content of K2O is more preferably 0.03% or more, further preferably 0.05% or more, particularly preferably 0.10% or more, and most preferably 0.50% or more.

[0221] On the other hand, from the viewpoint of avoiding a decrease in surface compressive stress (K_CS) during the strengthening treatment using sodium salt, the K2O content is more preferably 1.80% or less, further preferably 1.50% or less, and particularly preferably 1.40% or less.

[0222] It should be noted that it may not actually contain K2O.

[0223] From the viewpoint of suppressing the rise of devitrification temperature and reducing the crystal growth rate, the total R2O content of Li2O, Na2O and K2O is more preferably 10.00% to 45.00%, further preferably 15.00% to 40.00%, and particularly preferably 17.00% to 38.00%.

[0224] From the viewpoint of further improving the deep-layer stress in chemical strengthening properties, the Li2O content relative to the aforementioned R2O ratio ([Li2O] / ([Li2O]+[Na2O]+[K2O], hereinafter also referred to as "Li2O / R2O") is more preferably 0.50 or more, and even more preferably 0.55 or more. From the viewpoint of further improving chemical resistance, the Li2O / R2O ratio is more preferably 0.99 or less, even more preferably 0.98 or less, and particularly preferably 0.95 or less.

[0225] From the viewpoint of further improving the deep-layer stress in chemical strengthening properties, the ratio of Na2O content to R2O ([Na2O] / ([Li2O]+[Na2O]+[K2O], hereinafter also referred to as "Na2O / R2O") is preferably greater than 0, more preferably 0.01 or more, even more preferably 0.02 or more, and particularly preferably 0.04 or more. From the viewpoint of further improving chemical resistance, Na2O / R2O is preferably 0.40 or less, more preferably 0.35 or less.

[0226] From the viewpoint of further improving the resistivity of the glass, the ratio of K2O content to R2O ([K2O] / ([Li2O]+[Na2O]+[K2O], hereinafter also referred to as "K2O / R2O") is preferably 0.001 or more, more preferably 0.004 or more, and even more preferably 0.01 or more. From the viewpoint of improving the compressive stress near the surface in chemical strengthening properties, the K2O / R2O ratio is preferably 0.50 or less, more preferably 0.40 or less, even more preferably 0.30 or less, and particularly preferably 0.20 or less.

[0227] It should be noted that K2O / R2O can be 0.

[0228] Furthermore, from the viewpoint of suppressing the rise in devitrification temperature and reducing the crystal growth rate, the product of Li₂O / R₂O, Na₂O / R₂O, and K₂O / R₂O is more preferably 0.00005 or more, and even more preferably 0.0001 or more. Moreover, the above product is more preferably 0.020 or less.

[0229] It should be noted that the above product can be 0.

[0230] The content of Al2O3 relative to the above-mentioned R2O ratio ([Al2O3 / ([Li2O]+[Na2O]+[K2O], hereinafter also referred to as "Al2O3 / R2O")) is preferably 0.05 or more, more preferably 0.10 or more, even more preferably 0.12 or more, and even more preferably 0.13 or more. The Al2O3 / R2O ratio is preferably 0.80 or less, more preferably 0.75 or less, and even more preferably 0.70 or less.

[0231] The value represented by [Al2O3]-[Na2O]-[K2O]+[Li2O] is preferably 10.00% or more, more preferably 14.00% or more. Furthermore, the above value is preferably 40.00% or less, more preferably 37.00% or less.

[0232] To reduce viscosity during melting, MgO may be included. The content of MgO 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 the following order.

[0233] On the other hand, from the viewpoint that the compressive stress layer is easily increased 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 the following order.

[0234] Furthermore, the presence of MgO can suppress the phase transformation from β-quartz solid solution to β-spodumene, and can suppress the precipitation of β-spodumene crystals. Therefore, the presence of MgO is preferred. From the above viewpoint, it is preferable to contain more than 0.5% and less than or equal to 7.0% MgO. Further preferred ranges are as described above.

[0235] It may also contain no MgO at all.

[0236] CaO is a component that improves the meltability of glass, and therefore may contain CaO. The CaO content is more preferably 0.005% or more, and even more preferably 0.01% or more. On the other hand, from the viewpoint that it is easy to increase 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.

[0237] SrO is a component that improves the meltability of glass, and therefore may contain SrO. The content of SrO is more preferably 0.10% or more, further preferably 0.15% or more, and particularly preferably 0.50% or more.

[0238] From the viewpoint that chemical strengthening treatment can easily increase the compressive stress value, the content of SrO is more preferably 3.00% or less, further preferably 2.00% or less, particularly preferably 1.00% or less, and most preferably 0.50% or less.

[0239] It may also be that it does not actually contain SrO.

[0240] BaO is a component that improves the meltability of glass, and therefore may contain BaO. When BaO is present, its content is preferably 0.10% or more, more preferably 0.15% or more, and even more preferably 0.50% or more.

[0241] From the viewpoint that chemical strengthening treatment can easily increase the compressive stress value, 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.

[0242] It may also not contain BaO in substance.

[0243] ZnO is a component that improves the meltability of glass. The ZnO content is more preferably 0.10% or more, further preferably 0.15% or more, and particularly preferably 0.50% or more.

[0244] From the viewpoint that chemical strengthening treatment can easily increase the compressive stress value, the ZnO content is more preferably 3.00% or less, further preferably 2.00% or less, particularly preferably 1.00% or less, and most preferably 0.50% or less.

[0245] It may also not contain ZnO in substance.

[0246] lnW is a parameter representing 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.

[0247] lnW=ln(([Li2O]+[Na2O]+[K2O]+[MgO]+[CaO]+[SrO]+[BaO]+[ZnO])! / ([Li2O]!×[Na2O]!×[K2O]!×[MgO]!×[CaO]!×[SrO]!

[0248] In formula (W1), [Li2O], [Na2O], [K2O], [MgO], [CaO], [SrO], [BaO] and [ZnO] represent the molar percentage content of each component Li2O, Na2O, K2O, MgO, CaO, SrO, BaO and ZnO, respectively, based on oxides.

[0249] Additionally, the ! symbol indicates factorial operation on a positive integer. For example, [XO]! means rounding down the decimal part of the molar percentage of component XO based on oxides, and then multiplying that integer by the factorial. For instance, when Na2O is 4.80 mol%, the factorial of "4" is calculated as 4 × 3 × 2 × 1.

[0250] The higher the value of lnW, the higher the degree of mixing of the aforementioned metal oxides, and the better the devitrification of the glass can be suppressed. From this perspective, lnW is preferably 10 or more, more preferably 12 or more, even more preferably 13 or more, and particularly preferably 14 or more. lnW is preferably 20 or less, more preferably 18 or less, and even more preferably 17 or less.

[0251] TiO2 is a component that is highly effective in suppressing the solar eclipse effect on glass and is a material that forms crystal nuclei, therefore it can be contained in the glass. When TiO2 is present, its content is preferably 0.05% or more, more preferably 0.10% or more.

[0252] On the other hand, TiO2 has light absorption properties, so from the viewpoint of preventing color development in glass, the content of TiO2 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.

[0253] It may also be that it does not actually contain TiO2.

[0254] ZrO2 is a component that easily increases the surface compressive stress of chemically strengthened glass-ceramics. Furthermore, it is a material that forms crystal nuclei, and therefore may contain ZrO2. 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 the following order. The ZrO2 content is more preferably 4.80% or less, and even more preferably 4.60% or less.

[0255] P2O5 readily increases the compressive stress layer during chemical strengthening. The content of P2O5 is more preferably 0.20% or more, and even more preferably 0.50% or more.

[0256] On the other hand, from the viewpoint of improving 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 the formation of ripples during melting, it is preferable that the material contains virtually no P2O5.

[0257] B2O3 reduces the brittleness of glass and improves its crack resistance, or it improves the meltability of glass. The content of B2O3 is preferably 0.50% or more, more preferably 1.00% or more, and even more preferably 1.20% or more.

[0258] On the other hand, from the viewpoint 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 the formation of ripples during melting, it is preferable that the material contains virtually no B2O3.

[0259] Y₂O₃ is a component that easily increases the surface compressive stress of chemically strengthened glass-ceramics and reduces the crystal growth rate. The content of Y₂O₃ is preferably greater than 0.00%, more preferably 0.10% or more, 0.20% or more, and 0.50% or more in the following order. On the other hand, from the viewpoint that it easily increases the compressive stress layer during chemical strengthening treatment, the content of Y₂O₃ is more preferably 2.00% or less, and more preferably 1.50% or less.

[0260] It may also not contain Y2O3 in substance.

[0261] From the viewpoint of improving initial meltability, the total content of ZrO2 and Y2O3 is more preferably 6.00% or less. There is no particular limitation on the lower limit of the total content of ZrO2 and Y2O3, but from the viewpoint of improving 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 the following order.

[0262] La2O3 is not essential, but it may be included for the same reasons as Y2O3. The content 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 La2O3, it is difficult to increase the compressive stress layer during chemical strengthening treatment; therefore, the content 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.

[0263] The preferred formulation does not actually contain La2O3.

[0264] Nb₂O₅, Ta₂O₅, Gd₂O₃, and CeO₂ have the effect of suppressing the sunlight effect on glass and are components that improve meltability, therefore they can be included. When these components are included, their respective contents are preferably 0.03% or more, more preferably 0.10% or more, further preferably 0.50% or more, particularly preferably 0.80% or more, and most preferably 1.00% or more. On the other hand, they are preferably 3.00% or less, more preferably 2.00% or less, and further preferably 1.00% or less.

[0265] Fe2O3 absorbs heat rays, thus improving the meltability of glass. Therefore, when producing glass in large quantities using large melting furnaces, the presence of Fe2O3 is preferable. In this case, the Fe2O3 content, based on oxide mass%, is preferably 0.002% or more, more preferably 0.005% or more, even more preferably 0.007% or more, and particularly preferably 0.01% or more. On the other hand, when Fe2O3 is present in excess, it causes coloration. Therefore, from the viewpoint of improving the transparency of glass, its content, based on oxide mass%, is preferably 0.30% or less, more preferably 0.04% or less, even more preferably 0.025% or less, and particularly preferably 0.015% or less.

[0266] Furthermore, other coloring components may be added within the limits of achieving the desired chemical strengthening properties. Examples of other coloring components include: Co3O4, MnO2, NiO, CuO, Cr2O3, V2O5, Bi2O3, SeO2, Er2O3, and Nd2O3.

[0267] As a clarifying agent during glass melting, it may appropriately contain SO3, chlorides, fluorides, etc. It is preferable that it does not contain As2O3. If it does contain Sb2O3, it is preferably 0.30% or less, more preferably 0.10% or less, and most preferably not contained.

[0268] From the viewpoint of clarifying bubbles in the glass, the SnO2 content is more preferably 0.05% or more, and even more preferably 0.07% or more. Furthermore, in order to suppress the formation of defects, the SnO2 content is preferably 1.00% or less, more preferably 0.80% or less, even more preferably 0.70% or less, and particularly preferably 0.50% or less.

[0269] Chemically strengthened glass is preferably microcrystalline glass.

[0270] The crystals included in the glass-ceramic are preferably selected from one or more crystals chosen from the group consisting of lithium silicate crystals, lithium aluminosilicate crystals and lithium phosphate crystals, and more preferably selected from one or more crystals chosen from the group consisting of lithium silicate crystals and lithium aluminosilicate crystals.

[0271] Lithium silicate crystals are preferably lithium metasilicate (Li₂SiO₃) crystals and lithium disilicate (Li₂Si₂O₅) crystals. Lithium phosphate crystals are preferably lithium orthophosphate (Li₃PO₄) crystals. Lithium aluminosilicate crystals are preferably β-spodumene crystals (LiAlSi₂O₆), β-quartz solid solution crystals (LiAlSiO₄), and petalite crystals (LiAlSi₄O₅). 10 )wait.

[0272] In addition, the obtained microcrystalline glass preferably 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.

[0273] When the chemically strengthened glass is a glass-ceramic, from the viewpoint of improving mechanical strength, its crystallinity is preferably 10% or more, more preferably 15% or more, further preferably 20% or more, and particularly preferably 25% or more. Furthermore, to improve transparency, it is preferably 70% or less, more preferably 60% or less, and further preferably 50% or less. Lower crystallinity also provides advantages in terms of ease of bending and shaping by heating. Crystallinity can be calculated using the Riedbold method from X-ray diffraction intensity. The Riedbold method is described in the "Crystal Analysis Handbook" edited by the Editorial Committee of the "Crystal Analysis Handbook" of the Crystallographic Society of Japan (Kyoritsu Publishing, 1999, pp. 492-499).

[0274] When the chemically strengthened glass is a glass-ceramic, in order to improve transparency, the average particle size of the precipitated crystals is preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, and particularly preferably 100 nm or less. The average particle size of the precipitated crystals can be determined from transmission electron microscopy (TEM) images. Alternatively, it can be estimated from scanning electron microscopy (SEM) images.

[0275] (physical properties)

[0276] The preferred physical properties of chemically strengthened glass are described below.

[0277] The devitrification temperature of chemically strengthened glass is preferably below 1300°C. More preferably, it is below 1280°C, and even more preferably below 1250°C. Particularly preferred are below 1240°C, below 1230°C, below 1220°C, and below 1210°C in the following order. There is no particular limitation on the lower limit of the devitrification temperature, which is generally above 1100°C.

[0278] The crystallization onset temperature Tcs of chemically strengthened glass (e.g., glass composed of the matrix glass described above), as determined by DSC, is preferably 500°C or higher. There is no particular upper limit to the crystallization onset temperature; it is typically 800°C or lower.

[0279] When the crystallization initiation temperature Tcs is within the above range, for example, when heat treatment is performed at 500°C to 600°C for 1 to 6 hours and then at 600°C to 800°C for 0.5 to 6 hours, crystals can be precipitated in the glass, thereby obtaining a chemically strengthened glass as a microcrystalline glass.

[0280] The above heat treatment can be carried out in three stages. For example, it can be held at 500℃~600℃ for 1 hour to 6 hours, at 550℃~650℃ for 0.5 hours to 6 hours, and at 600℃~800℃ for 0.5 hours to 6 hours, thereby obtaining chemically strengthened glass.

[0281] From the viewpoint of reducing warpage after chemical strengthening, 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 facilitating float forming, Tg 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.

[0282] The crystallization peak temperature Tc of the chemically strengthened glass composed of the aforementioned matrix glass is preferably 600°C or higher, more preferably 650°C or higher, and even more preferably 700°C or higher. Stable forming is possible with a crystallization peak temperature Tc of 600°C or higher. It should be noted that, most preferably, no crystallization peak is observed. There is no particular upper limit to the crystallization peak temperature Tc, which is typically below 950°C.

[0283] The β-OH value of chemically strengthened glass is preferably 0.1 mm. -1 The above, more preferably 0.15mm -1 The above is further preferred to be 0.2mm. -1 The above is particularly preferred, with 0.22mm being the optimal size. -1 The optimal value is 0.25mm. -1 above.

[0284] The β-OH value is an indicator of the moisture content in glass. Glass with a high β-OH value tends to have a lower softening point and is easier to bend and process. On the other hand, from the viewpoint of improving the strength of glass through chemical strengthening, a higher β-OH value tends to result in a lower compressive stress (CS) after chemical strengthening treatment. From these considerations, a β-OH value of 0.5 mm is preferred. -1 The following is more preferably 0.4mm -1 Hereinafter, 0.3mm is further preferred. -1 the following.

[0285] Fracture toughness value (K) of chemically strengthened glass IC The preferred value is 0.80 MPa·m 1 / 2 The above, more preferably 0.85 MPa·m 1 / 2 The above is further preferably 0.90 MPa·m 1 / 2 The above, especially preferred, is 1.00 MPa·m 1 / 2 The optimal value is 1.10 MPa·m.1 / 2 That's all. There is no particular upper limit to the fracture toughness value; typically it is 1.60 MPa·m. 1 / 2 the following.

[0286] The Young's modulus of chemically strengthened glass is preferably 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 below 120 GPa.

[0287] The method for determining the Young's modulus of chemically strengthened glass is as described in the following examples section.

[0288] <Application>

[0289] The chemically strengthened glass of the present invention is useful, for example, as a protective glass.

[0290] The aforementioned protective glass can also be used for surface protection purposes such as displays and solar cell modules.

[0291] In particular, the chemically strengthened glass of the present invention is useful as protective glass for mobile devices such as mobile phones, smartphones, portable information terminals (PDAs), and tablet terminals. Furthermore, it is also useful for protective glass for display devices such as televisions (TVs), personal computers (PCs), and touch panels that are not intended for portability; protective glass for the surface of solar cell modules; building materials such as elevator walls, walls of buildings (full-screen displays) and windows; and interior decorations for desktops, automobiles, and aircraft. Additionally, it is useful as protective glass for the aforementioned items. Furthermore, through bending processing and bending forming, it can also be applied to applications such as housings with curved shapes.

[0292] The chemically strengthened glass of the present invention has excellent resistance to high temperature and high humidity, and is therefore preferably used in applications that require high temperature and high humidity environments.

[0293] Example

[0294] The present invention will now be described in more detail based on embodiments.

[0295] The materials, amounts, proportions, processing contents, and processing steps shown in the following embodiments can be appropriately modified without departing from the spirit of the invention. Therefore, the scope of the invention should not be interpreted as limited by the embodiments shown below.

[0296] It should be noted that Examples 1 to 3, 5, 7 and 9 described below are examples, Examples 4, 8 and 10 are comparative examples, and Example 6 is a reference example.

[0297] Preparation of Chemically Strengthened Glass

[0298] First, glass materials A to D were obtained by melting glass raw materials in a platinum crucible in such a way that each glass has the composition shown in Table 1 as a molar percentage based on oxides.

[0299] More specifically, select commonly used glass raw materials from oxides, hydroxides, carbonates or nitrates used as glass raw materials, and weigh them in a way that the glass weight reaches 1000g.

[0300] Next, the mixed raw materials are placed in a platinum crucible and melted in a resistance-heated electric furnace at 1500℃~1700℃ for about 3 hours to degas and homogenize, thus obtaining molten glass. The obtained molten glass is poured into mold material and held at a temperature 50℃ higher than the glass transition temperature for 1 hour, and then cooled to room temperature at a rate of 0.5℃ / min to obtain a glass block. The obtained glass block is cut and ground to produce sheet glass.

[0301] The thicknesses of the plate glass are shown in Tables 2 and 3.

[0302] It should be noted that after glass material A was made into plate-shaped glass, it was heat-treated by heating to 550°C and holding for 2 hours, and then heating to 720°C and holding for 2 hours.

[0303] In addition, after glass material C was made into plate-shaped glass, it was heat-treated by heating to 540°C and holding for 4 hours, then heating to 600°C and holding for 4 hours, and then heating to 700°C and holding for 2 hours.

[0304] In addition, after glass material D was made into plate-shaped glass, it was heat-treated by heating to 550°C and holding for 2 hours, and then heating to 720°C and holding for 2 hours.

[0305] The above heat treatment yields a glass-ceramic with precipitated crystals. This glass-ceramic is then used as a chemically strengthened glass.

[0306] The crystals precipitated after the above heat treatment and their crystallinity are shown in Table 1 below.

[0307] In addition, another glass block was subjected to the same heat treatment as described above, and the fracture toughness value (K) was obtained. IC The sample pieces used for the determination, as well as the sample pieces used for determining Young's modulus, were used to determine the fracture toughness and Young's modulus by the methods described later.

[0308]

[0309] <Preparation of Chemically Strengthened Glass>

[0310] The chemically strengthened glasses (glass materials A to D) obtained in the above-described steps were subjected to chemical strengthening treatment under the conditions described in Tables 2 and 3, thereby obtaining chemically strengthened glasses for each example. As the added silica, silica gel (average particle size 1.3 mm, specific surface area 450 m²) was used. 2 / g, pore volume 0.75ml / g, pore size 6nm).

[0311] In addition, Tables 2 and 3 also record the pH of the aqueous solution when the molten salt used in the chemical fortification process is solidified and dissolved in pure water to prepare an aqueous solution with a concentration of 9% by mass (“Aqueous Solution pH” in Tables 2 and 3).

[0312] <Hydrogen Atom Concentration>

[0313] The hydrogen atom concentration was determined following the above operating procedures, and the parameters were calculated. The meaning of each parameter is as described above.

[0314] <Determination of Young's Modulus>

[0315] The Young's modulus of chemically strengthened glass was determined using sample pieces cut from the above-described glass material preparation steps. Specifically, the determination was performed using the sample pieces via ultrasonic pulse method according to JIS R 1602.

[0316] It should be noted that the Young's modulus was measured using the same method after chemical fortification, and the result was the same as that before chemical fortification.

[0317] Determination of Fracture Toughness Value

[0318] Using the sample pieces cut during the above-mentioned glass material preparation steps, the fracture toughness value K of the chemically strengthened glass is determined. IC The fracture toughness value was determined using the DCDC method described above.

[0319] It should be noted that the fracture toughness value K was measured using the same method after chemical strengthening. IC The result was the same as the value before chemical fortification.

[0320] <Evaluation of High Temperature and High Humidity Resistance>

[0321] The high temperature and high humidity resistance of chemically strengthened glass in each case was evaluated according to the following operating procedures.

[0322] Specifically, firstly, the chemically strengthened glass samples were cut into 5cm squares to obtain test samples. The obtained test samples were placed in a constant temperature and humidity bath (ESPEC SH-642) and left to stand for 240 hours at a temperature of 85°C and a relative humidity of 85%.

[0323] After each test sample was allowed to stand, the haze of each test sample was measured. Additionally, the haze of each test sample was measured before it was allowed to stand.

[0324] The haze was measured using an HZ-V3 manufactured by Suga Testing Machine Co., Ltd. under the following conditions.

[0325] Optical conditions: Two-beam configuration (JIS K7361.7136)

[0326] Light source: C-beam

[0327] The following table records the fog level after the high temperature and high humidity test and the ratio of fog level after the high temperature and high humidity test to fog level before the high temperature and high humidity test.

[0328] In addition, the high temperature and high humidity resistance was compared and evaluated for each glass material. Specifically, for each glass material, the highest haze ratio of the aforementioned chemically strengthened glass obtained by chemical strengthening treatment without the addition of silica (silica gel) was compared with the aforementioned haze ratio of each chemically strengthened glass for evaluation. More specifically, for glass material A, the aforementioned haze ratio before and after the high temperature and high humidity test of Example 4 was compared with the aforementioned haze ratio of Examples 1 to 3 and Example 5 for evaluation.

[0329] <Stress Measurement>

[0330] As described above, the stress distribution was obtained using a scattered light photoelastic stress gauge, 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.

[0331] <Results>

[0332] The types of chemically strengthened glass, chemical strengthening conditions, the above-mentioned measurement results, and the above-mentioned evaluation results for each example are shown in Tables 2 and 3. Additionally, Table 4 shows stress-related parameters obtained from stress distribution.

[0333] In Tables 2 and 3, the silica content is expressed as the silica content relative to the total mass of the molten salt excluding silica.

[0334]

[0335] The results shown in Tables 2 and 3 confirm that when glass material A is used as the chemically strengthened glass, it is comparable to that of A. 1.0μm The value is less than 2.000 × 10 20 atoms / cm 3 Compared to the chemically strengthened glass in Example 4, A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 The chemically strengthened glass of the present invention in Examples 1 to 3 and 5 above has a low haze value after high temperature and high humidity test and excellent high temperature and high humidity resistance.

[0336] Relatedly, for glass material A, SIMS-based analysis was performed using the same method as for obtaining the hydrogen atom concentration distribution, and the results of the determination of the Na and K atom concentration distributions are shown in Table 4.

[0337] In Table 5, for example, in the "Na Concentration" column, "C" 0.5μm The description is the same as in Table 3, indicating the Na atom concentration at a depth of 0.50 μm from the surface. The other descriptions are the same.

[0338] Additionally, the “Na+K” column displays the value obtained by summing the values ​​of the parameters corresponding to the “Na concentration” column and the parameters corresponding to the “K concentration” column.

[0339]

[0340] As shown in Table 5, compared with the chemically strengthened glass of Example 4, the ratio of the sum of 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 in the chemically strengthened glass of the present invention (Examples 1 to 3 and Example 5) at a depth of 0.50 μm from the surface to the average sum of the average Na atom concentration and average K atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface (C) 0.5μm / A 2.75μm The K atom concentration ratio (C0.05) is smaller than that of the chemically strengthened glass of Example 4. Furthermore, compared to the chemically strengthened glass of Example 4, the chemically strengthened glass of the present invention (Examples 1-3 and 5) has a lower K atom concentration ratio (C0.05). 0.5μm / A 2.75μm )Small.

[0341] That is, it can be said that compared with the chemically strengthened glass of Example 4, the Na concentration near the surface of the chemically strengthened glass of Examples 1 to 3 and Example 5 is relatively low, and the K concentration near the surface is relatively low.

[0342] Therefore, it is believed that through the above mechanism, even under high temperature and high humidity conditions, the haze of the chemically strengthened glass of the present invention is not likely to increase.

[0343] As shown in Tables 2 and 3, when glass material B is used as the chemically strengthened glass and chemical strengthening is performed using a molten salt that satisfies both necessary conditions 1 and 2 (Example 6), A 1.0μm The value did not reach 2.000 × 10 20 atoms / cm 3 above.

[0344] The results shown in Tables 2 and 3 confirm that, when using glass material C as the chemically strengthened glass, it is comparable to A. 1.0μm The value is less than 2.000 × 10 20 atoms / cm 3 Compared to the chemically strengthened glass in Example 8, A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 The chemically strengthened glass of the present invention in Example 7 above has a low haze value after high temperature and high humidity test, and excellent high temperature and high humidity resistance.

[0345] Similarly, the results shown in Tables 2 and 3 confirm that when glass material D is used as the chemically strengthened glass, compared with A... 1.0μm The value is less than 2.000 × 10 20 atoms / cm 3 Compared to the chemically strengthened glass of Example 10, A 1.0μm The value is 2.000 × 10 20 atoms / cm 3 The chemically strengthened glass of the present invention in Example 9 above has a low haze value after high temperature and high humidity test, and excellent high temperature and high humidity resistance.

Claims

1. A chemically strengthened glass, wherein, The average hydrogen atom concentration in the depth range of 0.75 μm to 1.25 μm measured from the surface of the chemically strengthened glass is 2.000 × 10⁻⁶. 20 atoms / cm 3 above.

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 of the chemically strengthened glass to the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface of the chemically strengthened glass is 1.490 or higher.

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 of the chemically strengthened glass to the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface of the chemically strengthened glass is 1.250 or higher.

4. The chemically strengthened glass according to claim 1 or 2, wherein, The absolute value of the slope of the hydrogen atom concentration relative to depth, calculated from the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm measured from the surface of the chemically strengthened glass and the hydrogen atom concentration at a depth of 0.50 μm measured from the surface of the chemically strengthened glass, is 0.600 × 10⁻⁶. 20 atoms / cm 3 Above μm.

5. The chemically strengthened glass according to claim 1 or 2, wherein, The value obtained by subtracting the average hydrogen atom concentration in the depth range of 2.50 μm to 3.00 μm from the surface of the chemically strengthened glass from the hydrogen atom concentration at a depth of 0.50 μm measured from the surface of the chemically strengthened glass is 1.800 × 10⁻⁶. 20 atoms / cm 3 above.

6. The chemically strengthened glass according to claim 1 or 2, wherein, The approximate integral value of the hydrogen atom concentration in the depth range of 0.00 μm to 1.00 μm from the surface of the chemically strengthened glass is 15.000 × 10⁻⁶ with respect to the average hydrogen atom concentration in the depth range of 0.75 μm to 1.25 μm from the surface of the chemically strengthened glass. -5 Less than cm.

7. The chemically strengthened glass according to claim 1 or 2, wherein, The chemically strengthened glass is a microcrystalline glass.

8. The chemically strengthened glass according to claim 7, wherein, The chemically strengthened glass comprises 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 of the chemically strengthened glass is 10% to 70%.

10. The chemically strengthened glass according to claim 1 or 2, wherein, The chemically strengthened glass, in molar percentages based on oxides, comprises: 40.00%~75.00% SiO2, 2.00%~20.00% Al2O3, 9.00%~40.00% Li2O, 1.00%~8.00% Na2O, 0.00% to 2.00% K2O.

11. The chemically strengthened glass according to claim 1 or 2, wherein, The haze of the chemically strengthened glass after undergoing a high-temperature and high-humidity resistance test at 85°C and 85% relative humidity for 240 hours was less than 20 times that of the chemically strengthened glass before the high-temperature and high-humidity resistance test.

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

13. The chemically strengthened glass according to claim 1 or 2, wherein, The fracture toughness value K of the chemically strengthened glass IC 0.82 MPa·m 1 / 2 above.

14. The chemically strengthened glass according to claim 1 or 2, wherein, The chemically strengthened glass has a Young's modulus of 84 GPa or higher.

15. A method for manufacturing chemically strengthened glass, comprising a method for obtaining chemically strengthened glass by performing one or more chemical strengthening treatments in which the chemically strengthened glass is brought into contact with molten salt, wherein, The chemically strengthened glass, in molar percentages based on oxides, comprises: 40.00%~75.00% SiO2, 2.00%~20.00% Al2O3, 9.00%~40.00% Li2O, 1.00%~5.00% Na2O, 0.00%~1.40% K2O, The molten salt used in at least one of the chemical enhancement treatments satisfies the following necessary conditions 1 and 2. Necessary condition 1: The molten salt contains silicic acid; Necessary condition 2: When the molten salt is solidified and dissolved in pure water to prepare an aqueous solution with a concentration of 9% by mass, the pH of the aqueous solution is below 6.

0.

16. The method for manufacturing chemically strengthened glass according to claim 15, wherein, The chemical enhancement treatment is performed more than twice.

17. The method for manufacturing chemically strengthened glass according to claim 15, wherein, The chemical enhancement treatment is performed three or more times.

18. The method for manufacturing chemically strengthened glass according to claim 16, wherein, The chemical enhancement treatment is performed twice, and the molten salt used in the first chemical enhancement treatment satisfies both necessary condition 1 and necessary condition 2.

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

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

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

22. The method for manufacturing chemically strengthened glass according to claim 15 or 16, wherein, The ratio of the LiNO3 content of the molten salt used in the first chemical strengthening process of the chemical strengthening process to the Li2O content of the chemically strengthened glass is 75 mol% or less.

23. The method for manufacturing chemically strengthened glass according to claim 15 or 16, wherein, The molten salt that satisfies condition 1 further comprises sodium metasilicate.

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