Preparation method of chemically strengthened glass with high stress performance and strengthened glass

Abstract

The present invention discloses a method for preparing chemically strengthened glass with high stress performance and the strengthened glass. The preparation method of the present invention provides a method for rapidly screening raw glass sheets. By utilizing the relationship between the maximum tensile stress linear density achieved by lithium aluminosilicate glass under salt bath conditions in an extreme experiment and the bifurcation threshold of the glass of that formulation, raw glass sheets of different formulations can be rapidly screened to determine whether they are suitable for preparing strengthened glass that meets the requirements of the present invention, possessing both high stress performance and high individual strength. Furthermore, the suitability of single-step binary ion exchange chemical strengthening can be determined, providing a basis for optimizing the subsequent chemical strengthening process. By employing single-step binary ion exchange chemical strengthening, the strengthening process is greatly simplified, strengthening costs are reduced, and strengthening time can be effectively controlled. While achieving high stress performance, the strengthened glass can still maintain excellent individual strength.

Description

Technical Field

[0001] The present invention relates to the field of glass technology, and in particular to a preparation method of lithium aluminum silicon chemically strengthened glass with high stress performance and the strengthened glass. Background Art

[0002] At present, the display protection materials and exterior shell protection materials of portable smart electronic devices such as mobile phones, tablets, and electronic watches are all made of glass, and the vast majority are lithium aluminum silicate chemically strengthened glass. As protective glass for displays of portable terminals such as smartphones, it has certain requirements for strength (especially drop strength) and glass monomer performance. Therefore, lithium aluminum silicate chemically strengthened glass with high stress performance (including high surface compressive stress (CS), high pressure stress depth (DOL_0) and high tensile stress linear density (CT_LD)) and excellent monomer strength (including higher drop resistance and four-point bending strength) has a large market space. In addition, in order to ensure emergency use after customers' broken screens, more and more mobile phone manufacturers have further required that the glass will not produce many small fragments after breaking.

[0003] In order to prepare lithium aluminum silicate chemically strengthened glass with high stress performance and high monomer strength that meets market demand, most glass manufacturers usually constantly adjust the glass formula to obtain different glass sheets, and then adjust the strengthening process for different glass sheets to prepare strengthened glass. This process is very cumbersome and has a long cycle, and it cannot ensure that lithium aluminum silicate chemically strengthened glass that meets the requirements is obtained. The reason may be that the developed glass sheets do not meet the requirements for preparing high stress performance chemically strengthened glass. Even if the chemical strengthening process is continuously adjusted, the strengthened glass still cannot meet the high performance requirements. It may also be because the strengthening process has not been adjusted to the preferred strengthening process for the specific formula glass sheet, which often leads to over-strengthening or insufficient strengthening, thereby causing product waste. In addition, the existing strengthening process generally adopts a two-step method, which has a complicated strengthening process and high cost.

[0004] Therefore, in-depth and systematic research on glass sheets and strengthening processes to find specific rules will help to more accurately and efficiently prepare lithium aluminum silicon chemically strengthened glass with high stress performance and high monomer strength that meets the requirements. Summary of the Invention

[0005] The present invention aims to provide a method for preparing lithium aluminum silicate chemically strengthened glass with high stress resistance and high individual strength, as well as lithium aluminum silicate chemically strengthened glass prepared using this method. Through in-depth and systematic research on glass stock and strengthening processes, the inventors of the present invention have discovered the characteristic requirements that glass stock must meet when preparing chemically strengthened glass with both high stress resistance and high individual strength. Based on these characteristic requirements, it is possible to quickly screen out glass stock formulations that meet the requirements, and it is also possible to effectively avoid missing glass stock formulations that have been directly abandoned by manufacturers due to incompatibility with the strengthening process. Furthermore, the present invention provides a suitable single-step strengthening process for the glass stock corresponding to the screened glass stock formulation. Compared to the existing two-step strengthening process, the strengthening process provided by the present invention greatly simplifies the strengthening process, reduces strengthening costs, and effectively controls the strengthening time. While achieving high stress resistance, it can ensure that the strengthened glass still has excellent individual strength. It can also ensure that the fragments produced by the strengthened glass after immediate rupture are mainly large fragments, thus meeting the needs of emergency use.

[0006] The present invention provides a method for preparing chemically strengthened glass with high stress performance, comprising the following steps:

[0007] S1. Screening out a glass formula suitable for preparing chemically strengthened glass with high stress performance by single-step binary ion exchange chemical strengthening, and using the glass formula as the original glass sheet to be strengthened. The specific steps include:

[0008] (1) Place the unstrengthened lithium aluminosilicate glass in a 100 wt% sodium nitrate bath at 450°C and test the maximum tensile stress linear density CT_LD that the glass can obtain. max1 At the same time, the bifurcation threshold of the glass with the same formula as the lithium aluminum silicate glass was tested and CT_LD was calculated. max1 The difference from the bifurcation threshold;

[0009] (2) Screen out the bifurcation threshold greater than 40000MPa / mm and CT_LD max1 Subtract the glasses with a difference of 3000 MPa / mm in the bifurcation threshold and determine the corresponding glass formula. Then, place the glass with this formula in a mixed salt bath of 5 wt% sodium nitrate and 95 wt% potassium nitrate at 450°C and test the maximum tensile stress linear density CT_LD that the glass can obtain. max2 , and upon reaching CT_LD max2 When the surface compressive stress CS2 of the glass is measured, CT_LD is calculated. max2 Ratio to bifurcation threshold;

[0010] (3) Screening out CT_LD max2For glasses with a ratio to the bifurcation threshold greater than 1.05 and a CS2 greater than 800 MPa, the corresponding glass formula is determined and the glass with the formula is used as the original glass sheet to be strengthened;

[0011] S2. The glass sheet to be strengthened selected in S1 is subjected to single-step binary ion exchange chemical strengthening. By controlling the process conditions of the single-step binary ion exchange, chemically strengthened glass with high stress performance can be produced.

[0012] Furthermore, in S2, when the glass sheet undergoes single-step binary ion exchange chemical strengthening, the salt bath used includes: sodium nitrate greater than 0wt% and less than or equal to 15wt% and potassium nitrate greater than or equal to 85wt% and less than 100wt%, and the salt bath temperature is 400-500°C.

[0013] Furthermore, in S2, when the glass sheet undergoes single-step binary ion exchange chemical strengthening, the salt bath used includes: greater than or equal to 2.5wt% and less than or equal to 15wt% of sodium nitrate and greater than or equal to 85wt% and less than or equal to 97.5wt% of potassium nitrate.

[0014] Furthermore, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange satisfies:

[0015] a. The bifurcation threshold is greater than 40,000 MPa / mm, the tensile stress linear density CT_LD is greater than 40,000 MPa / mm, and the difference between the tensile stress linear density CT_LD and the bifurcation threshold is -3,000 MPa / mm to 3,000 MPa / mm;

[0016] b. Surface compressive stress CS is greater than 800MPa.

[0017] Furthermore, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0018] c. The compressive stress depth DOL_0 is greater than 16.00% of the thickness of the obtained lithium aluminum silicate chemically strengthened glass.

[0019] Furthermore, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0020] d. CS 50 Satisfies the formula:

[0021] Among them, CS 50is the compressive stress at a depth of 50 microns from the surface of the tempered glass, in MPa; a is -486.26; b is 0.449; c is (217-10t) to (217+70 / t), where t is the thickness of the tempered glass, in mm.

[0022] Furthermore, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0023] e. When the weight of the falling ball is 56 g, the falling height of the lithium aluminum silicate chemically strengthened glass is greater than or equal to 0.70 m when converted to a thickness of 0.7 mm.

[0024] Furthermore, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0025] f. The lithium aluminosilicate chemically strengthened glass has a four-point bending strength of greater than 700 MPa when converted to a thickness of 0.7 mm.

[0026] Furthermore, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0027] g. The lithium aluminosilicate chemically strengthened glass has a sandpaper drop resistance height of greater than 1.0 m, preferably greater than or equal to 1.2 m, and more preferably greater than or equal to 1.5 m, when converted to a thickness of 0.7 mm.

[0028] The present invention also provides a lithium aluminum silicate chemically strengthened glass, which is prepared by the above-mentioned preparation method. The strengthened glass has a bifurcation threshold greater than 40,000 MPa / mm, a tensile stress linear density CT_LD greater than 40,000 MPa / mm, and the difference between the tensile stress linear density CT_LD and the bifurcation threshold is between -3,000 MPa / mm and 3,000 MPa / mm; the surface compressive stress CS of the strengthened glass is greater than 800 MPa.

[0029] Furthermore, the compressive stress depth DOL_0 of the strengthened glass is greater than 16.00% of the thickness of the strengthened glass.

[0030] Furthermore, the CS of the tempered glass 50 Satisfies the formula:

[0031] Among them, CS 50 is the compressive stress at a depth of 50 microns from the surface of the tempered glass, in MPa; a is -486.26; b is 0.449; c is (217-10t) to (217+70 / t), where t is the thickness of the tempered glass, in mm.

[0032] Furthermore, the difference between the tensile stress linear density CT_LD of the tempered glass and the bifurcation threshold is -2000 MPa / mm to 3000 MPa / mm; and / or

[0033] The surface compressive stress CS of the tempered glass is greater than or equal to 850 MPa.

[0034] Furthermore, when the weight of the falling ball is 56 g, the falling ball resistance height of the tempered glass when converted to a thickness of 0.7 mm is greater than or equal to 0.70 m; and / or

[0035] The tempered glass has a four-point bending strength greater than 700 MPa when converted to a thickness of 0.7 mm.

[0036] Furthermore, the tempered glass has a sandpaper drop resistance greater than 1.0 m, preferably greater than or equal to 1.2 m, and more preferably greater than or equal to 1.5 m, when converted to a thickness of 0.7 mm.

[0037] Furthermore, the tempered glass is broken into a plurality of fragments after being broken by the probe, and the average length of the fragments is greater than 10 mm.

[0038] The glass formula selected by the present invention is lithium aluminum silicate glass, which includes SiO2, Al2O3, Li2O, and Na2O in terms of oxides. The glass of this system can be chemically strengthened by ion exchange, and the deep stress can be obtained by sodium-lithium exchange. + With Na in ion exchange salt bath + Na + -Li + The glass formula may also include one or more of P2O5, B2O3, Y2O3, La2O3, Tm2O3, MgO, TiO2, ZrO2, and K2O.

[0039] The present invention also provides an electronic terminal as a consumer product, comprising:

[0040] a housing comprising a front surface, a rear surface, and side surfaces;

[0041] and an electronic assembly partially located within the housing, the electronic assembly including a display device located at or adjacent to a front surface of the housing;

[0042] The front surface or / and rear surface or / and side surface comprises lithium aluminum silicon chemically strengthened glass prepared by the above preparation method;

[0043] Also included is a covering product covering the front surface of the housing or located on the display device, the covering product comprising the lithium aluminum silicon chemically strengthened glass prepared by the above preparation method;

[0044] The electronic terminals as consumer products include mobile phones, tablet computers, photovoltaic devices, or other electronic terminals (including electronic watches, etc.).

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The preparation method of the present invention provides a method for rapidly screening glass blanks. By utilizing the relationship between the maximum tensile stress linear density that can be obtained by lithium aluminosilicate glass in the salt bath conditions of the extreme experiment (including a 100wt% sodium nitrate salt bath at 450°C and a mixed salt bath of 5wt% sodium nitrate and 95wt% potassium nitrate at 450°C) and the bifurcation threshold of the glass of the formula, glass blanks of different formulas can be rapidly screened to determine whether they are suitable for preparing tempered glass with both high stress performance and high monomer strength that meets the requirements of the present invention, and further determine whether they are suitable for single-step binary ion exchange chemical strengthening, providing a basis for the optimization of their subsequent chemical strengthening process, and avoiding the waste of manpower and material resources by optimizing the strengthening process for unsuitable glass blanks (the glass blanks used are unsuitable and cannot obtain high anti-destructive strength). This screening method can also effectively avoid omitting glass blank formulas that are directly abandoned by manufacturers due to incompatibility with the strengthening process.

[0047] 2. The inventors of the present invention provide a suitable single-step strengthening process for the glass sheets corresponding to the selected glass sheet formula. Compared with the existing two-step strengthening process, the single-step strengthening process provided by the present invention greatly simplifies the strengthening process, reduces the strengthening cost, and can effectively control the strengthening time, avoiding the problems of increased volume expansion of the strengthened glass product, increased surface microcracks, and increased risk of high-temperature salt bath erosion on the glass surface, thereby avoiding the problem of decreased single-unit strength performance of the strengthened glass product. By using the single-step binary ion exchange chemical strengthening process provided by the present invention on the selected lithium aluminum silicate glass sheets, while obtaining high stress performance, it can ensure that the strengthened glass still has excellent single-unit strength, and can also ensure that the fragments generated after the strengthened glass immediately breaks are mainly large fragments to meet emergency use needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a test diagram of the sandpaper drop resistance height;

[0049] Figure 2 It is a diagram of glass breakage patterns;

[0050] Figure 3It is a test diagram of the drop height of the falling ball;

[0051] Figure 4 This is a schematic diagram of the nine points on the sample surface to be impacted during the ball drop height test;

[0052] Figure 5 It is a schematic diagram of the four-point bending strength test;

[0053] Figure 6 This is a photograph showing the fracture of the tempered glass product of Example 3 after a sandpaper drop test. DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0055] 1. The relevant special names and related measurement methods involved in the present invention are explained as follows:

[0056] (1) Original glass: glass that has not been chemically strengthened by ion exchange.

[0057] (2) Strengthened glass: It is a solid composite material obtained by chemically strengthening the original glass. During the high-temperature chemical strengthening treatment, the alkali metal ions with large ionic radius (such as potassium ions and sodium ions) in the salt bath will replace the alkali metal ions with small ionic radius (such as sodium ions and lithium ions) in the original glass, resulting in an exchange ion volume difference and compressive stress on the glass surface.

[0058] (3) Surface compressive stress CS: After the glass sheet is chemically strengthened, the alkali metal ions with smaller surface radius are replaced by alkali metal ions with larger radius. Due to the crowding effect of the alkali metal ions with larger radius, compressive stress is generated on the glass surface, which is called surface compressive stress.

[0059] (4) Compressive stress depth DOL: refers to the distance from any surface of the tempered glass to the position where the compressive stress is zero.

[0060] (5)CS 50 :CS 50 It is the compressive stress at a depth of 50 micrometers from the surface of the strengthened glass (50 μm from the surface of the strengthened glass to the inside).

[0061] Surface compressive stress CS, CS 50 2. Measurement of compressive stress depth (DOL): Orihara's FSM6000 and SLP2000 can be used to measure the surface high-pressure stress area and the deep low-pressure stress area, respectively, and the stress curves can be fitted using PMC software. Of course, other stress testers that can measure both the surface high-pressure stress area and the deep low-pressure stress area can also be used.

[0062] (6) Tensile stress linear density CT_LD: The ratio of the sum of the tensile stresses obtained from the SLP stress instrument test to the thickness of the strengthened glass.

[0063] After chemical strengthening, a tensile stress layer forms within the tempered glass. The tensile stress layer has an upper boundary spaced a certain distance from the upper surface of the tempered glass and a lower boundary spaced a certain distance from the lower surface of the tempered glass. A curve is plotted with the tensile stress at a point on a line segment within the tensile stress layer that is perpendicular to both the upper and lower boundaries and whose upper and lower endpoints fall on the upper and lower boundaries, respectively, as the Y-axis and the distance from the corresponding point to the upper boundary as the X-axis, denoted as the tensile stress curve. The ratio of the definite integral of the tensile stress curve to the thickness of the tempered glass is denoted as the tensile stress linear density, which is the ratio of the sum of the tensile stresses of the tempered glass measured by the SLP-2000 stress meter to the thickness of the glass.

[0064] The compressive stress and tensile stress in chemically strengthened glass are in equilibrium. The SLP-2000 stress meter is more accurate in measuring the tensile stress region of glass. Therefore, the tensile stress integral and thickness ratio are used to represent the stress per unit thickness of the strengthened glass and to characterize the stress level of the chemically strengthened glass.

[0065] (7)CT_LD max : Chemical strengthening is carried out under salt bath conditions in the extreme experiment. As the strengthening time increases, the tensile stress line density CT_LD presents a parabolic form and has a maximum point, which is called the maximum tensile stress line density CT_LD max .

[0066] CT_LD max The test method is: when chemically strengthening in the salt bath conditions of the extreme experiment, take out the glass at regular intervals (such as 1h, 0.5h, etc.) to test its CT_LD value (after each test, immediately put it into the salt bath to continue strengthening, and take it out again for testing when the next test time is reached), and analyze the test results to obtain its CT_LD max .

[0067] The salt bath conditions used in the limit experiment in the present invention are: 100wt% sodium nitrate salt bath at 450℃ or a mixed salt bath of 5wt% sodium nitrate and 95wt% potassium nitrate at 450℃. The maximum tensile stress linear density of the glass obtained in the 100wt% sodium nitrate salt bath at 450℃ is CT_LD max1 The maximum tensile stress linear density of glass obtained in a mixed salt bath of 5wt% sodium nitrate and 95wt% potassium nitrate at 450℃ is CT_LD max2 .

[0068] (9) Bifurcation threshold: The bifurcation threshold is the tensile stress linear density of the tempered glass when the glass cross section bifurcates in the immediate fracture test of the tempered glass. The immediate fracture test: the center point of the tempered glass sample is used as the breaking point, and a "stress release device" is used (for details, please refer to the article "Study on the intrinsic influencing factors of the drop resistance of the cover glass treated with double strength", from Glass and Enamel. 2021, 49 (02)) to generate a crack at the breaking point. The crack extends under the action of its internal tensile stress, such as Figure 2 a and Figure 2 b, rather than a starburst due to excessive impact force, such as Figure 2 c. When the glass crack just produces bifurcation, the tensile stress linear density of the strengthened glass sample is the bifurcation threshold.

[0069] Bifurcation threshold test method:

[0070] Test the CT_LD that can be obtained from the glass sheet corresponding to a certain glass formula under extreme experimental conditions max Then, the tempered glass samples with different CT_LD were strengthened under the salt bath conditions of the extreme experiment, and the CT_LD range was from 30000MPa / mm to CT_LD max , increasing by about 1000MPa / mm, 1500MPa / mm or 2000MPa / mm. For example, the glass sheet corresponding to the glass formula to be tested is strengthened under the salt bath conditions of the extreme experiment to obtain a CT_LD of about 30000MPa / mm, about 31000MPa / mm, about 32000MPa / mm, about 33000MPa / mm, about 34000MPa / mm, about 36000MPa / mm... max A bifurcation threshold test was conducted on a tempered glass sample. That is, the center point of the tempered glass sample was used as the failure point, and a "stress release device" was used to cause a crack to appear at the failure point. When the glass crack happened to bifurcate, the tensile stress linear density of the tempered glass sample was the bifurcation threshold.

[0071] Since the bifurcation threshold is a reference indicator for the ability of glass to safely accommodate stress and is an inherent characteristic of the original glass sheet itself, it will not change with changes in glass strengthening conditions, but only with changes in the glass formulation. Therefore, the salt bath conditions for the extreme experiment in the present invention can be a 100wt% sodium nitrate salt bath at 450°C, or a mixed salt bath of 5wt% sodium nitrate and 95wt% potassium nitrate at 450°C.

[0072] Note that when the CT_LD of the strengthened glass sample has reached CT_LD max , and perform an immediate fracture test on it. If it is found that the glass crack still does not bifurcate, then it is judged that the bifurcation threshold of this formula glass is greater than the CT_LD obtained by the limit experiment.max .

[0073] (10) Ball drop resistance test method:

[0074] Prepare 2.5D tempered glass samples measuring (60-80) x (150-170) x 0.7 mm. A 56g steel ball is dropped vertically from above the tempered glass sample. Each batch of at least 10 samples is subjected to a drop test. Starting from a drop height of 0.20 m, the ball is dropped once at nine points on the sample surface. The ball is held during rebound to prevent a second impact. If the sample does not break, the drop is increased by 0.1 m and repeated until it breaks. The average of the two broken heights is taken as the drop height.

[0075] (11) Four-point bending strength test method:

[0076] A 2.5D sample of tempered glass was prepared with dimensions of (60-80) x (150-170) x 0.7 mm. A four-bar bending tester (model: MK-9991WQ) was used, with an upper span of 20 cm and a lower span of 40 cm. The sample was compressed downward at a constant speed of 10 mm / min until it broke. The compressive strength at the time of breaking was then measured.

[0077] Each batch of samples shall consist of at least 10 pieces, and the average compressive strength of the batch samples shall be taken as the four-point bending strength.

[0078] (12) Sandpaper drop resistance test method:

[0079] Prepare a 2D sample of tempered glass measuring 50 x 50 x 0.7 mm. Prepare a weighted module made of an acrylic sheet and a metal weight block. Secure the tempered glass to one side of the weighted module using foam and double-sided tape. The acrylic sheet and metal block weigh 200 g, and the foam and double-sided tape are 0.2-0.3 mm thick.

[0080] The prepared test sample is dropped from a specified height onto a marble floor covered with 120-grit sandpaper in a manner such that the tempered glass faces downward. The acceleration of the impact drop is 9.5-9.8 m / s. 2 . To simulate the normal use of the mobile phone and the state of accidentally falling.

[0081] Each batch of samples shall consist of at least 10 pieces. The samples shall be dropped from a height of 0.4m. If they are not broken, the height shall be increased by 0.1m each time and dropped again until they are broken. The average of the broken heights shall be taken as the anti-drop height.

[0082] 2. A method for preparing chemically strengthened glass with high stress performance.

[0083] This embodiment provides a method for preparing chemically strengthened glass with high stress performance, comprising the following steps:

[0084] S1. Screening out a glass formula suitable for preparing chemically strengthened glass with high stress performance by single-step binary ion exchange chemical strengthening, and using the glass formula as the original glass sheet to be strengthened. The specific steps include:

[0085] (1) Unstrengthened lithium aluminosilicate glass (the lithium aluminosilicate glass here can be lithium aluminosilicate glass prepared by conventional methods such as float method and overflow method, and the preparation method of the glass is not particularly limited) is placed in a 100 wt% sodium nitrate salt bath at 450°C, and the maximum tensile stress linear density CT_LD that the glass can obtain is tested. max1 At the same time, the bifurcation threshold of the glass with the same formula as the lithium aluminum silicate glass was tested and CT_LD was calculated. max1 The difference from the bifurcation threshold;

[0086] (2) Screen out the bifurcation threshold greater than 40000MPa / mm and CT_LD max1 Subtract the glasses with a difference of 3000 MPa / mm in the bifurcation threshold and determine the corresponding glass formula. Then, place the glass with this formula in a mixed salt bath of 5 wt% sodium nitrate and 95 wt% potassium nitrate at 450°C and test the maximum tensile stress linear density CT_LD that the glass can obtain. max2 , and upon reaching CT_LD max2 When the surface compressive stress CS2 of the glass is measured, CT_LD is calculated. max2 Ratio to bifurcation threshold;

[0087] (3) Screening out CT_LD max2 For glasses with a ratio to the bifurcation threshold greater than 1.05 and a CS2 greater than 800 MPa, the corresponding glass formula is determined and the glass with the formula is used as the original glass sheet to be strengthened;

[0088] S2. The glass sheet to be strengthened selected in S1 is subjected to single-step binary ion exchange chemical strengthening. By controlling the process conditions of the single-step binary ion exchange, chemically strengthened glass with high stress performance can be produced.

[0089] In the prior art, adjustments to the lithium aluminosilicate glass formula do not always result in the lithium aluminosilicate glass meeting the requirements for producing high-stress chemically strengthened glass. Often, after multiple chemical strengthening adjustments, it is discovered that the glass stock with the specified glass formula is unsuitable for producing high-stress chemically strengthened glass, which undoubtedly results in a waste of raw material resources. Even if the resulting glass stock meets the requirements for producing high-stress chemically strengthened glass, an inappropriate strengthening process will result in insufficient improvement in the glass stock's performance, making it impossible to produce high-performance strengthened glass. This can also easily lead to manufacturers abandoning their painstakingly developed glass formulas due to performance failures.

[0090] Through in-depth and systematic research on glass substrates and strengthening processes, the inventors of this invention discovered that lithium aluminosilicate glass, which can be used to prepare chemically strengthened glass with high stress performance, must be able to withstand the stress caused by chemical strengthening. If the stress tolerance limit is too low, the stress effect achieved by chemical strengthening will be extremely limited. Based on this, the inventors further discovered that when preparing chemically strengthened glass with both high stress performance and high monomer strength, the glass substrate must meet certain characteristic requirements: the bifurcation threshold of the glass substrate must be greater than 40,000 MPa / mm, and the maximum tensile stress linear density CT_LD of the glass substrate must be greater than 40,000 MPa / mm in a 100wt% sodium nitrate salt bath at 450°C. max1 The difference from the bifurcation threshold must be greater than or equal to 3000 MPa / mm. At the same time, the inventors further discovered that when the glass sheet is based on the above, it also has the following characteristics: the maximum tensile stress linear density CT_LD obtained by the glass sheet in a mixed salt bath of 5wt% sodium nitrate and 95wt% potassium nitrate at 450°C max2 The ratio to the bifurcation threshold is greater than 1.05 and reaches CT_LD max2 When the surface compressive stress CS2 of the resulting glass is greater than 800 MPa, the original glass can be directly strengthened in a single step to produce chemically strengthened glass with both high stress resistance and high individual strength. This research result greatly simplifies the strengthening process for producing chemically strengthened glass with both high stress resistance and high individual strength, effectively reducing the strengthening cost.

[0091] In an embodiment, the bifurcation threshold of the glass sheet corresponding to the screened glass formula is greater than 40,000 MPa / mm. For example, the bifurcation threshold of the glass sheet corresponding to the screened glass formula is greater than 40,000 MPa / mm, greater than 41,000 MPa / mm, greater than 42,000 MPa / mm, greater than 43,000 MPa / mm, greater than 44,000 MPa / mm, greater than 45,000 MPa / mm, greater than 46,000 MPa / mm, greater than 47,000 MPa / mm, greater than 48,000 MPa / mm, greater than 49,000 MPa / mm, greater than 50,000 MPa / mm, or greater than 53,000 MPa / mm. It should be understood that in an embodiment, any of the above ranges may be combined with any other ranges.

[0092] In certain embodiments, the bifurcation threshold of the glass sheet corresponding to the screened glass formula includes the following ranges:

[0093] MPa / mm to 52000 MPa / mm, 40000 MPa / mm to 53000 MPa / mm, 45000 MPa / mm to 50000 MPa / mm, 41000 MPa / mm to 45000 MPa / mm, 44000 MPa / mm to 45000 MPa / mm, 46000 MPa / mm to 50000 MPa / mm, 47000 MPa / mm to 51000 MPa / mm, 45000 MPa / mm to 48000 MPa / mm, 44000 MPa / mm to 52000 MPa / mm, 40000 MPa / mm to 53000 MPa / mm, 50000 MPa / mm to 52000 MPa / mm, and all ranges and subranges between the above values.

[0094] In the embodiment, the maximum tensile stress linear density CT_LD that can be obtained by the glass sheet corresponding to the screened glass formula is max1 The difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm. For example, the maximum tensile stress linear density CT_LD that can be obtained for the glass sheet corresponding to the screened glass formula is max1The difference minus the bifurcation threshold is greater than or equal to 3000MPa / mm, greater than or equal to 3100MPa / mm, greater than or equal to 3200MPa / mm, greater than or equal to 3300MPa / mm, greater than or equal to 3400MPa / mm, greater than or equal to 3500MPa / mm, greater than or equal to 3600MPa / mm, greater than or equal to 3700MPa / mm, greater than or equal to 3800MPa / mm, greater than or equal to 3900MPa / mm, greater than or equal to 4000MPa / mm, greater than or equal to 450 The present invention relates to a method for producing a thermal conductivity of a carbon fiber that is greater than or equal to 0 MPa / mm, a thermal conductivity of 1000 MPa / mm, a thermal conductivity of 1000 MPa / mm, a thermal conductivity of 2000 MPa / mm, a thermal conductivity of 25000 MPa / mm, a thermal conductivity of 30000 MPa / mm, a thermal conductivity of 34000 MPa / mm, a thermal conductivity of 38000 MPa / mm, and a thermal conductivity of 40000 MPa / mm. It should be understood that in embodiments, any of the above ranges may be combined with any other ranges.

[0095] In some embodiments, the maximum tensile stress linear density CT_LD that can be obtained by the glass sheet corresponding to the screened glass formula is max1 The difference ranges from the bifurcation threshold include: 3000MPa / mm~40000MPa / mm, 3100MPa / mm~38000MPa / mm, 3200MPa / mm~34000MPa / mm, 3300MPa / mm~30000MPa / mm, 3400MPa / mm~28000MPa / mm, 3500MPa / mm~25000MPa / mm, 3600MPa / mm~ 20000 MPa / mm, 3700 MPa / mm to 15000 MPa / mm, 3800 MPa / mm to 10000 MPa / mm, 3900 MPa / mm to 7000 MPa / mm, 4000 MPa / mm to 5000 MPa / mm, 4500 MPa / mm to 5500 MPa / mm, 4800 MPa / mm to 5600 MPa / mm, and all ranges and subranges between the above values.

[0096] In the embodiment, the maximum tensile stress linear density CT_LD that can be obtained by the glass sheet corresponding to the screened glass formula is max2 The ratio to the bifurcation threshold is greater than 1.05. For example, the maximum tensile stress linear density CT_LD that can be obtained for the glass sheet corresponding to the screened glass formula is max2The ratio of the bifurcation threshold to the bifurcation threshold is greater than 1.05, greater than 1.10, greater than 1.20, greater than 1.25, greater than 1.30, greater than 1.35, greater than 1.40, greater than 1.45, and greater than 1.50. It should be understood that, in embodiments, any of the above ranges can be combined with any other ranges. In certain embodiments, the maximum tensile stress linear density CT_LD that can be obtained for the glass blank corresponding to the screened glass formula is max2 The ratio to the bifurcation threshold ranges are 1.05-1.50, 1.05-1.15, 1.08-1.15, 1.09-1.17, 1.15-1.20, 1.25-1.30, 1.15-1.25, 1.30-1.35, 1.15-1.22, and all ranges and subranges between the above values.

[0097] In an embodiment, upon reaching CT_LD max2 When the glass sheet corresponding to the selected glass formula has a CS2 greater than 800 MPa, for example, the CS2 of the selected glass is greater than 800 MPa, greater than 810 MPa, greater than 820 MPa, greater than 830 MPa, greater than 840 MPa, greater than 850 MPa, greater than 860 MPa, greater than 870 MPa, greater than 880 MPa, greater than 890 MPa, greater than 900 MPa, greater than 920 MPa, greater than 950 MPa, greater than 1000 MPa, greater than 1050 MPa, or greater than 1100 MPa. It should be understood that in embodiments, any of the above ranges may be combined with any other ranges. In certain embodiments, the CS2 value range that can be obtained for the glass raw material corresponding to the screened glass formula is 800MPa~1100MPa, 800MPa~850MPa, 830MPa~860MPa, 800MPa~820MPa, 840MPa~890MPa, 850MPa~900MPa, 860MPa~900MPa, 890MPa~910MPa, 830MPa~910MPa, 850MPa~950MPa, 900MPa~1000MPa, 950MPa~1000MPa, 1000MPa~1100MPa, and all ranges and sub-ranges between the above values.

[0098] In this embodiment, in S2, when the glass sheet undergoes single-step binary ion exchange chemical strengthening, the salt bath used includes: sodium nitrate greater than 0wt% and less than or equal to 15wt% and potassium nitrate greater than or equal to 85wt% and less than 100wt%, and the salt bath temperature is 400-500°C; preferably, when the glass sheet undergoes single-step binary ion exchange chemical strengthening, the salt bath used includes: sodium nitrate greater than or equal to 2.5wt% and less than or equal to 15wt% and potassium nitrate greater than or equal to 85wt% and less than or equal to 97.5wt%.

[0099] The duration of single-step binary ion exchange chemical strengthening of raw glass is related to the salt bath composition, salt bath temperature, glass thickness, and glass formulation. The properties of the resulting strengthened glass are tested periodically (this timed testing refers to removing the glass from the salt bath for testing at regular intervals (e.g., 1 hour, 0.5 hours, etc.). If the glass does not meet the performance requirements after testing, it is placed back in the salt bath for further strengthening). When the strengthened glass meets the performance requirements for the desired strengthened glass product, the single-step binary ion exchange chemical strengthening is stopped. The strengthening time and salt bath conditions (including salt bath composition and temperature) used for the strengthening are recorded. The recorded strengthening time can be used later when strengthening raw glass sheets of the same formulation and thickness under the same salt bath conditions.

[0100] In the implementation:

[0101] Based on the total amount of sodium nitrate (NaNO3) and potassium nitrate (KNO3) in the salt bath, the salt bath of each embodiment may include greater than 0 wt% and less than or equal to 15 wt%, greater than 0 wt% and less than or equal to 14 wt%, greater than 0 wt% and less than or equal to 13 wt%, greater than 0 wt% and less than or equal to 12 wt%, greater than 0 wt% and less than or equal to 11 wt%, greater than 0 wt% and less than or equal to 10 wt%, greater than 0 wt% and less than or equal to 9 wt%, greater than 0 wt% and less than or equal to 8 wt%, greater than 0 wt% and less than or equal to 7 wt%, greater than or equal to 2.5 wt% and less than or equal to 1. % and less than, or equal to, sodium nitrate, greater than or equal to 7 wt %, greater than or equal to 2.5 wt % and less than, or equal to 15 wt %, greater than or equal to 7 wt %, greater than or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 11 wt % and less than, or equal to 15 wt %, greater than or equal to 12 wt % and less than, or equal to 13 wt % and less than, or equal to 15 wt %, greater than or equal to 15 wt %, greater than or equal to 14 wt % and less than, or any and all subranges formed from any of these endpoints.

[0102] The salt bath of various embodiments may include 85 wt% to less than 100 wt%, 85 wt% to less than 100 wt%, 86 wt% to less than 100 wt%, 87 wt% to less than 100 wt%, 88 wt% to less than 100 wt%, 85 wt% to less than 97.5 wt%, 89 wt% to less than 97.5 wt%, 90 wt% to less than 97.5 wt%, 91 wt% to less than 97.5 wt%, 92 wt% to less than 97.5 wt%, 93 wt% to less than 97.5 wt%, 94 wt% to less than 97.5 wt%, 95 wt% to less than 97.5 wt% potassium nitrate in the salt bath, based on the total amount of sodium nitrate (NaNO3) and potassium nitrate (KNO3) in the salt bath, or any and all subranges formed by any of these endpoints.

[0103] The single-step binary ion exchange salt bath temperature of various embodiments can be 400-500°C, 420-425°C, 425-430°C, 430-435°C, 435-440°C, 440-445°C, 445-450°C, 420-435°C, 430-440°C, 440-450°C, 435-450°C, 425-440°C, or any and all subranges formed by any of these endpoints.

[0104] By applying the single-step binary ion exchange chemical strengthening process provided in this embodiment to the lithium aluminosilicate glass substrate corresponding to the selected glass formulation, the strengthening time can be effectively controlled, avoiding problems such as increased volume expansion, surface microcracks, and increased risk of glass surface erosion in the strengthened glass product, thereby preventing the problem of decreased individual strength performance in the strengthened glass product. In other words, by adopting the preparation method provided in this embodiment, while achieving high stress resistance, the strengthened glass can still maintain excellent individual strength. Furthermore, it can ensure that the fragments produced after immediate breakage of the strengthened glass are primarily large fragments, thus meeting the needs of emergency use.

[0105] In this embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange satisfies:

[0106] a. The bifurcation threshold is greater than 40,000 MPa / mm, the tensile stress linear density CT_LD is greater than 40,000 MPa / mm, and the difference between the tensile stress linear density CT_LD and the bifurcation threshold is -3,000 MPa / mm to 3,000 MPa / mm;

[0107] b. Surface compressive stress CS is greater than 800MPa.

[0108] In an embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the bifurcation threshold of the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange is greater than 40,000 MPa / mm, greater than 41,000 MPa / mm, greater than 42,000 MPa / mm, greater than 43,000 MPa / mm, greater than 44,000 MPa / mm, greater than 45,000 MPa / mm, greater than 46,000 MPa / mm, greater than 47,000 MPa / mm, greater than 48,000 MPa / mm, greater than 49,000 MPa / mm, greater than 50,000 MPa / mm, and greater than 53,000 MPa / mm. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges. In certain embodiments, in S2, the process conditions of the single-step binary ion exchange are controlled so that the bifurcation threshold of the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange has a value range including:

[0109] MPa / mm to 52000 MPa / mm, 40000 MPa / mm to 53000 MPa / mm, 45000 MPa / mm to 50000 MPa / mm, 41000 MPa / mm to 45000 MPa / mm, 44000 MPa / mm to 45000 MPa / mm, 46000 MPa / mm to 50000 MPa / mm, 47000 MPa / mm to 51000 MPa / mm, 45000 MPa / mm to 48000 MPa / mm, 44000 MPa / mm to 52000 MPa / mm, 40000 MPa / mm to 53000 MPa / mm, 50000 MPa / mm to 52000 MPa / mm, and all ranges and subranges between the above values.

[0110] In an embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the tensile stress linear density CT_LD of the lithium aluminosilicate chemically strengthened glass obtained after the single-step binary ion exchange is greater than 40,000 MPa / mm, greater than 41,000 MPa / mm, greater than 42,000 MPa / mm, greater than 43,000 MPa / mm, greater than 44,000 MPa / mm, greater than 45,000 MPa / mm, greater than 46,000 MPa / mm, greater than 47,000 MPa / mm, greater than 48,000 MPa / mm, greater than 49,000 MPa / mm, greater than 50,000 MPa / mm, and greater than 55,000 MPa / mm. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges. In certain embodiments, in S2, the process conditions of the single-step binary ion exchange are controlled so that the tensile stress linear density CT_LD of the lithium aluminosilicate chemically strengthened glass obtained after the single-step binary ion exchange has a value range including:

[0111] 40000 MPa / mm to 45000 MPa / mm, 40000 MPa / mm to 50000 MPa / mm, 45000 MPa / mm to 51000 MPa / mm, 41000 MPa / mm to 48000 MPa / mm, 44000 MPa / mm to 48000 MPa / mm, 46000 MPa / mm to 50000 MPa / mm, 47000 MPa / mm to 51000 MPa / mm, 45000 MPa / mm to 48000 MPa / mm, 44000 MPa / mm to 52000 MPa / mm, 40000 MPa / mm to 55000 MPa / mm, 50000 MPa / mm to 55000 MPa / mm, and all ranges and subranges between the above values.

[0112] In an embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the value range of the difference between the tensile stress linear density CT_LD of the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange and the bifurcation threshold is -3000MPa / mm to 3000MPa / mm, -2000MPa / mm to 3000MPa / mm, -1000MPa / mm to 3000MPa / mm, 0MPa / mm to 3000MPa / mm, -2500MPa / mm to 0MPa / mm, -2000MPa / mm to 1 MPa / mm, -500 MPa / mm to 2000 MPa / mm, -500 MPa / mm to 1500 MPa / mm, -800 MPa / mm to 1600 MPa / mm, and all ranges and subranges between the above values. In certain embodiments, in S2, the process conditions of the single-step binary ion exchange are controlled so that the difference between the tensile stress linear density CT_LD of the lithium aluminosilicate chemically strengthened glass obtained after the single-step binary ion exchange and the bifurcation threshold is -3000 MPa / mm, -2500 MPa / mm, -2000 MPa / mm, -1500 MPa / mm, -1000 MPa / mm, 0 MPa / mm, 500 MPa / mm, 1000 MPa / mm, 1500 MPa / mm, 2000 MPa / mm, 2500 MPa / mm, or 3000 MPa / mm. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0113] In certain embodiments, in S2, the process conditions of the single-step binary ion exchange are controlled so that the surface compressive stress CS of the lithium aluminosilicate chemically strengthened glass obtained after the single-step binary ion exchange is greater than 800 MPa, greater than 810 MPa, greater than 820 MPa, greater than 830 MPa, greater than 840 MPa, greater than 850 MPa, greater than 860 MPa, greater than 870 MPa, greater than 880 MPa, greater than 890 MPa, greater than 900 MPa, greater than 920 MPa, greater than 950 MPa, greater than 1000 MPa, greater than 1050 MPa, greater than 1100 MPa, greater than 1200 MPa, greater than 1300 MPa, or greater than 1400 MPa. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges. In certain embodiments, in S2, the process conditions of the single-step binary ion exchange are controlled so that the surface compressive stress CS of the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange has a value range comprising: 800 MPa to 1400 MPa, 810 MPa to 850 MPa, 830 MPa to 860 MPa, 810 MPa to 820 MPa, 840 MPa to 890 MPa, 850 MPa to 900 MPa, 860 MPa to 900 MPa, 890 MPa to 910 MPa, 830 MPa to 910 MPa, 850 MPa to 950 MPa, 900 MPa to 1000 MPa, 950 MPa to 1000 MPa, 1000 MPa to 1100 MPa, and all ranges and sub-ranges between the above values.

[0114] In this embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies the following conditions: c. the compressive stress depth DOL_0 is greater than 16.00% of the thickness of the obtained lithium aluminum silicate chemically strengthened glass.

[0115] In an embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the compressive stress depth DOL_0 of the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange is greater than 16.00% of the thickness of the original glass sheet, greater than 16.50% of the thickness of the original glass sheet, greater than 17.00% of the thickness of the original glass sheet, greater than 17.50% of the thickness of the original glass sheet, greater than 18.00% of the thickness of the original glass sheet, greater than 18.50% of the thickness of the original glass sheet, or greater than 19.00% of the thickness of the original glass sheet. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0116] In this embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0117] d. CS50 Satisfies the formula:

[0118] Among them, CS 50 is the compressive stress at a depth of 50 microns from the surface of the tempered glass, in MPa; a is -486.26; b is 0.449; c is (217-10t) to (217+70 / t), where t is the thickness of the tempered glass, in mm.

[0119] In the embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the CS of the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange is 0.7 mm when converted to a thickness of 0.7 mm. 50 The range is between 100 and 220 MPa.

[0120] In the present invention, "the obtained lithium aluminosilicate chemically strengthened glass has a thickness of 0.7 mm" specifically refers to the case where the obtained lithium aluminosilicate chemically strengthened glass has a thickness of 0.7 mm.

[0121] In this embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0122] e. When the weight of the falling ball is 56 g, the falling height of the lithium aluminum silicate chemically strengthened glass is greater than or equal to 0.70 m when converted to a thickness of 0.7 mm.

[0123] In embodiments, when the ball weight is 56 g, the ball drop resistance height of the lithium aluminosilicate chemically strengthened glass, when converted to a thickness of 0.7 mm, is greater than or equal to 0.70 m, greater than or equal to 0.75 m, greater than or equal to 0.80 m, greater than or equal to 0.85 m, greater than or equal to 0.90 m, greater than or equal to 0.95 m, greater than or equal to 1.00 m, or greater than or equal to 1.05 m. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges. In certain embodiments, when the ball weight is 56 g, the ball drop resistance height of the lithium aluminosilicate chemically strengthened glass, when converted to a thickness of 0.7 mm, is in the range of 0.75-0.85 m, 0.75-1.05 m, 0.85-1.00 m, 0.70-0.90 m, 0.95-1.00 m, 0.95-1.05 m, and all ranges and sub-ranges therebetween.

[0124] In this embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0125] f. The lithium aluminosilicate chemically strengthened glass has a four-point bending strength of greater than 700 MPa when converted to a thickness of 0.7 mm.

[0126] In embodiments, the lithium aluminosilicate chemically strengthened glass has a four-point flexural strength, when converted to a thickness of 0.7 mm, of greater than 700 MPa, greater than 750 MPa, greater than 760 MPa, greater than 770 MPa, greater than 780 MPa, greater than 790 MPa, greater than 800 MPa, greater than 820 MPa, greater than 850 MPa, greater than 900 MPa, greater than 1050 MPa, or greater than 1100 MPa. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges. In certain embodiments, the four-point bending strength of the lithium aluminosilicate chemically strengthened glass, when converted to a thickness of 0.7 mm, ranges from 750 MPa to 890 MPa, 750 MPa to 900 MPa, 760 MPa to 800 MPa, 790 MPa to 810 MPa, 870 MPa to 910 MPa, 850 MPa to 950 MPa, 880 MPa to 940 MPa, 900 MPa to 1000 MPa, 950 MPa to 1000 MPa, 1000 MPa to 1100 MPa, and all ranges and sub-ranges between the above values.

[0127] In this embodiment, in S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange further satisfies:

[0128] g. The lithium aluminosilicate chemically strengthened glass has a sandpaper drop resistance height of greater than 1.0 m, preferably greater than or equal to 1.2 m, and more preferably greater than or equal to 1.5 m, when converted to a thickness of 0.7 mm.

[0129] In certain embodiments, the lithium aluminosilicate chemically strengthened glass, when converted to a thickness of 0.7 mm, has a sandpaper drop resistance of greater than 1.0 m, 1.1 m, 1.2 m, 1.3 m, 1.4 m, 1.5 m, 1.6 m, 1.7 m, 1.8 m, 1.9 m, 2.0 m, 2.1 m, 2.2 m, 2.3 m, 2.4 m, 2.5 m, or 2.6 m. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0130] 3. A lithium aluminum silicon chemically strengthened glass.

[0131] This embodiment further provides a lithium aluminum silicate chemically strengthened glass, which is prepared by the above-mentioned preparation method. The strengthened glass has a bifurcation threshold greater than 40,000 MPa / mm, a tensile stress linear density CT_LD greater than 40,000 MPa / mm, and a difference between the tensile stress linear density CT_LD and the bifurcation threshold is between -3,000 MPa / mm and 3,000 MPa / mm. Preferably, the difference between the tensile stress linear density CT_LD and the bifurcation threshold is between -2,000 MPa / mm and 3,000 MPa / mm. The strengthened glass has a surface compressive stress CS greater than 800 MPa. Preferably, the surface compressive stress CS of the strengthened glass is greater than or equal to 850 MPa.

[0132] In this embodiment, the compressive stress depth DOL_0 of the tempered glass is greater than 16.00% of the thickness of the original glass sheet.

[0133] In an embodiment, the CS of the tempered glass 50 Satisfies the formula:

[0134] Among them, CS 50 is the compressive stress at a depth of 50 microns from the surface of the tempered glass, in MPa; a is -486.26; b is 0.449; c is (217-10t) to (217+70 / t), where t is the thickness of the tempered glass, in mm.

[0135] In certain embodiments, the CS of the tempered glass when converted to a thickness of 0.7 mm is 50 The range is between 100 and 220 MPa.

[0136] In an embodiment, when the weight of the falling ball is 56 g, the falling ball resistance height of the tempered glass when converted to a thickness of 0.7 mm is greater than or equal to 0.70 m.

[0137] In an embodiment, the tempered glass has a four-point bending strength greater than 700 MPa when converted to a thickness of 0.7 mm.

[0138] In an embodiment, the tempered glass has a sandpaper drop resistance greater than 1.0 m, preferably greater than or equal to 1.2 m, and more preferably greater than or equal to 1.5 m when converted to a thickness of 0.7 mm. The sandpaper used here is 120-grit sandpaper.

[0139] In an embodiment, the tempered glass is broken into several fragments after being broken by the probe, and the average length of the fragments is greater than 10 mm. The length of the fragments refers to the value of the maximum size of the fragments. The average length of the fragments specifically refers to the average length of several fragments formed by the breakage is greater than 10 mm. For example, there are 10 fragments formed after the breakage, and the lengths of these 10 fragments are 40 mm, 35 mm, 26 mm, 30 mm, 27 mm, 45 mm, 8 mm, 5 mm, 15 mm, and 3 mm, respectively. Then, the average length of the fragments is about 23 mm. The fact that the average length of the fragments is greater than 10 mm indicates that the lithium aluminum silicon chemically strengthened glass provided in this embodiment will not produce a large number of small fragments even after being broken to affect its subsequent use, thereby indicating that the lithium aluminum silicon chemically strengthened glass provided in this embodiment has excellent safety performance. For example Figure 6 In the test of the sandpaper drop resistance, the tempered glass product of Example 3 produced mainly large fragments when it was broken.

[0140] In certain embodiments, the strengthened glass is shattered by the probe into a plurality of fragments, and the average length of the formed fragments is greater than 10 mm, greater than 11 mm, greater than 13 mm, greater than 15 mm, greater than 16 mm, greater than 20 mm, greater than 25 mm, greater than 30 mm, or greater than 35 mm. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0141] The lithium aluminum silicate chemically strengthened glass provided in this embodiment has excellent stress resistance and monomer performance, and can be included in / applied in other products, such as watches, transparent armor, missile windows, fairings, substrate materials, new lamps, observation windows for equipment in high temperature, high pressure and corrosive environments, display protection materials and exterior shell protection materials for portable smart electronic devices (portable smart electronic devices include mobile phones, tablets, electronic watches, etc.), building products, transportation products (such as cars, trains, airplanes, marine vehicles, etc.), appliance products, or any product requiring a certain degree of transparency, scratch resistance, impact resistance, wear resistance, or a combination thereof.

[0142] In this embodiment, the glass formula selected is lithium aluminum silicate glass. In terms of oxides, the glass formula includes SiO2, Al2O3, Li2O, and Na2O. This system of glass can be chemically strengthened by ion exchange. The deep stress can be obtained by sodium-lithium exchange. The Li in the glass + With Na in ion exchange salt bath + Na + -Li +The glass formula may also include one or more of P2O5, B2O3, Y2O3, La2O3, Tm2O3, MgO, TiO2, ZrO2, and K2O.

[0143] 4. An electronic terminal as a consumer product.

[0144] This embodiment further provides an electronic terminal as a consumer product, including:

[0145] a housing comprising a front surface, a rear surface, and side surfaces;

[0146] and an electronic assembly partially located within the housing, the electronic assembly including a display device located at or adjacent to a front surface of the housing;

[0147] The front surface or / and rear surface or / and side surface comprises lithium aluminum silicon chemically strengthened glass prepared by the above method;

[0148] Also included is a covering product covering the front surface of the housing or located on the display device, the covering product comprising the lithium aluminum silicon chemically strengthened glass produced by the above method;

[0149] The electronic terminals as consumer products include mobile phones, tablet computers, photovoltaic devices, or other electronic terminals (such as electronic watches, etc.).

[0150] 5. The present invention will be described below through specific embodiments.

[0151] Table 1 shows the properties of the glass sheets corresponding to the glass formulations of glass 1 to 6.

[0152]

[0153]

[0154] Table 2 shows the properties of the glass sheets corresponding to the glass formulations 7 to 9 and comparative formulations 1 to 2.

[0155]

[0156] Note: When testing the bifurcation threshold, the glass sheet corresponding to the comparative formula 1 was strengthened at 450℃ in a 100wt% NaNO3 salt bath to obtain a CT_LD equal to CT_LD max1 The glass sample was subjected to an immediate fracture test and found that the glass crack did not bifurcate. Therefore, it was determined that the bifurcation threshold of the glass sheet with this formula was higher than the maximum tensile stress linear density value CT_LD that can be obtained by strengthening under the conditions of 450℃ and 100wt% NaNO3 salt bath.max1 .

[0157] Combining Table 1 and Table 2, it can be seen that the properties of glass sheets corresponding to different glass formulations are not the same. Specifically, different lithium aluminosilicate glass formulations, the bifurcation threshold of the glass, and the maximum tensile stress linear density CT_LD that can be obtained under the conditions of 450°C and 100wt% NaNO3 salt bath are different. max1 The maximum tensile stress linear density CT_LD that can be obtained under the conditions of 450℃, 5wt%NaNO3+95wt%KNO3 salt bath max2 , and when CT_LD is reached max2 The surface compressive stress CS2 of the glass will change.

[0158] Table 3 shows the strengthening process conditions used in Examples 3-5 and Comparative Examples 9-10 and the properties of the tempered glass obtained.

[0159]

[0160] Note: “430℃*5wt%NaNO3+95wt%KNO3*7h” means strengthening in a mixed salt bath of 5wt%NaNO3+95wt%KNO3 at 430℃ for 7h. Other similar expressions have similar meanings.

[0161] 2. After chemical strengthening, the thickness of the original glass sheet hardly changes. The difference between the thickness of the original glass sheet and the thickness of the lithium aluminum silicate chemically strengthened glass obtained by single-step binary ion exchange chemical strengthening is very small, within 10 microns, and is almost negligible. Therefore, when calculating the ratio of DOL_0 to the thickness of the lithium aluminum silicate chemically strengthened glass obtained by single-step binary ion exchange chemical strengthening, DOL_0 can be directly divided by the thickness of the original glass sheet.

[0162] 3. DOL_0 refers to the distance from the surface of the lithium aluminum silicate chemically strengthened glass to the position where the compressive stress is zero after single-step binary ion exchange chemical strengthening.

[0163] As shown in Table 3, when the glass sheet meets the screening requirements of the present invention, it can be directly strengthened by single-step binary ion exchange chemical strengthening using the single-step strengthening process of the present invention. 50, CS, DOL_0), and the resulting chemically strengthened glass can also maintain excellent individual performance, namely, the strengthened glass still has high ball drop resistance and four-point bending strength. However, when the original glass sheet does not meet the screening requirements of the present invention, if it is chemically strengthened by single-step binary ion exchange using the single-step strengthening process of the present invention, the resulting chemically strengthened glass has a low CT_LD and poor sandpaper drop resistance. The strengthened glasses produced in Comparative Examples 9 and 10 have significantly lower CT_LD than Examples 3-5, and show a significant decrease in sandpaper drop resistance.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing chemically strengthened glass with high stress performance, characterized in that: The steps include: S1. Screening out a glass formula suitable for preparing chemically strengthened glass with high stress performance by single-step binary ion exchange chemical strengthening, and using the glass formula as the original glass sheet to be strengthened. The specific steps include: (1) Place the unstrengthened lithium aluminosilicate glass in a 100 wt% sodium nitrate bath at 450°C and test the maximum tensile stress linear density CT_LD that the glass can obtain. max1 At the same time, the bifurcation threshold of the glass with the same formula as the lithium aluminum silicate glass was tested and CT_LD was calculated. max1 The difference from the bifurcation threshold; (2) Screen out the bifurcation threshold greater than 40000MPa / mm and CT_LD max1 Subtract the glasses with a difference of 3000 MPa / mm in the bifurcation threshold and determine the corresponding glass formula. Then, place the glass with this formula in a mixed salt bath of 5 wt% sodium nitrate and 95 wt% potassium nitrate at 450°C and test the maximum tensile stress linear density CT_LD that the glass can obtain. max2 , and upon reaching CT_LD max2 When the surface compressive stress CS2 of the glass is measured, CT_LD is calculated. max2 Ratio to bifurcation threshold; (3) Screening out CT_LD max2 For glasses with a ratio to the bifurcation threshold greater than 1.05 and a CS2 greater than 800 MPa, the corresponding glass formula is determined and the glass with the formula is used as the original glass sheet to be strengthened; S2. Subjecting the glass sheet to be strengthened selected in S1 to single-step binary ion exchange chemical strengthening, and controlling the process conditions of the single-step binary ion exchange to produce chemically strengthened glass with high stress performance; In S2, when the glass sheet undergoes single-step binary ion exchange chemical strengthening, the salt bath used includes: sodium nitrate greater than 0 wt% and less than or equal to 15 wt% and potassium nitrate greater than or equal to 85 wt% and less than 100 wt%, and the salt bath temperature is 400-500° C.; In S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange satisfies: a. The bifurcation threshold is greater than 40,000 MPa / mm, the tensile stress linear density CT_LD is greater than 40,000 MPa / mm, and the difference between the tensile stress linear density CT_LD and the bifurcation threshold is -3,000 MPa / mm to 3,000 MPa / mm; b. Surface compressive stress CS is greater than 800MPa.

2. The preparation method according to claim 1, characterized in that In S2, when the glass sheet undergoes single-step binary ion exchange chemical strengthening, the salt bath used includes: greater than or equal to 2.5 wt% and less than or equal to 15 wt% of sodium nitrate and greater than or equal to 85 wt% and less than or equal to 97.5 wt% of potassium nitrate.

3. The preparation method according to claim 1, characterized in that In S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange also satisfies: c. The compressive stress depth DOL_0 is greater than 16.00% of the thickness of the obtained lithium aluminum silicate chemically strengthened glass.

4. The preparation method according to claim 1, wherein In S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange also satisfies: d. CS 50 Satisfies the formula: Among them, CS 50 is the compressive stress at a depth of 50 microns from the surface of the tempered glass, in MPa; a is -486.26; b is 0.449; c is (217-10t) to (217+70 / t), where t is the thickness of the tempered glass, in mm.

5. The preparation method according to claim 1, characterized in that In S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange also satisfies: e. When the weight of the falling ball is 56 g, the falling height of the lithium aluminum silicate chemically strengthened glass is greater than or equal to 0.70 m when converted to a thickness of 0.7 mm.

6. The preparation method according to claim 1, characterized in that In S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange also satisfies: f. The lithium aluminosilicate chemically strengthened glass has a four-point bending strength of greater than 700 MPa when converted to a thickness of 0.7 mm.

7. The preparation method according to claim 1, characterized in that In S2, the process conditions of the single-step binary ion exchange are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the single-step binary ion exchange also satisfies: g. The lithium aluminum silicate chemically strengthened glass has a sandpaper drop resistance of greater than 1.0 m when converted to a thickness of 0.7 mm.

8. The preparation method according to claim 7, characterized in that The lithium aluminum silicate chemically strengthened glass has a sandpaper drop resistance height greater than or equal to 1.2 m when converted to a thickness of 0.7 mm.

9. The preparation method according to claim 7, characterized in that The lithium aluminum silicate chemically strengthened glass has a sandpaper drop resistance height greater than or equal to 1.5 m when converted to a thickness of 0.7 mm.

10. A lithium aluminum silicate chemically strengthened glass, the strengthened glass being prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The strengthened glass has a bifurcation threshold greater than 40,000 MPa / mm, a tensile stress linear density CT_LD greater than 40,000 MPa / mm, and a difference between the tensile stress linear density CT_LD and the bifurcation threshold is -3,000 MPa / mm to 3,000 MPa / mm; and a surface compressive stress CS of the strengthened glass is greater than 800 MPa.

11. The tempered glass according to claim 10, wherein The compressive stress depth DOL_0 of the strengthened glass is greater than 16.00% of the thickness of the strengthened glass.

12. The tempered glass according to claim 10, wherein CS of the tempered glass 50 Satisfies the formula: Among them, CS 50 is the compressive stress at a depth of 50 microns from the surface of the tempered glass, in MPa; a is -486.26; b is 0.449; c is (217-10t) to (217+70 / t), where t is the thickness of the tempered glass, in mm.

13. The tempered glass according to claim 10, wherein The difference between the tensile stress linear density CT_LD of the tempered glass and the bifurcation threshold is -2000 MPa / mm to 3000 MPa / mm; and / or The surface compressive stress CS of the tempered glass is greater than or equal to 850 MPa.

14. The tempered glass according to claim 10, wherein When the weight of the falling ball is 56 g, the height of the tempered glass against falling ball when converted to a thickness of 0.7 mm is greater than or equal to 0.70 m; and / or The tempered glass has a four-point bending strength greater than 700 MPa when converted to a thickness of 0.7 mm.

15. The tempered glass according to claim 10, wherein The tempered glass has a sandpaper drop resistance height greater than 1.0 m when converted to a thickness of 0.7 mm.

16. The tempered glass according to claim 15, wherein The tempered glass has a sandpaper drop resistance height of greater than or equal to 1.2 m when converted to a thickness of 0.7 mm.

17. The tempered glass according to claim 15, wherein The tempered glass has a sandpaper drop resistance height of greater than or equal to 1.5 m when converted to a thickness of 0.7 mm.

18. The tempered glass according to claim 10, wherein The tempered glass is broken into a plurality of fragments after being broken by the probe, and the average length of the fragments is greater than 10 mm.

19. An electronic terminal as a consumer product, characterized in that: include: a housing comprising a front surface, a rear surface, and side surfaces; and an electronic assembly partially located within the housing, the electronic assembly including a display device located at or adjacent to a front surface of the housing; The front surface or / and the rear surface or / and the side surface comprises lithium aluminum silicon chemically strengthened glass prepared by the preparation method according to any one of claims 1 to 9; Also included is a covering product covering the front surface of the housing or located on the display device, the covering product comprising lithium aluminum silicon chemically strengthened glass prepared by the preparation method according to any one of claims 1 to 9; The electronic terminals as consumer products include mobile phones, tablet computers, photovoltaic devices, or other electronic terminals.

Images