Preparation method of tempered glass with both high stress and high monomer strength and tempered glass

Abstract

The present invention discloses a method for preparing tempered glass with both high stress and high individual strength, and the tempered glass. The preparation method of the present invention provides a method for rapidly screening glass stock sheets. By utilizing the relationship between the maximum tensile stress linear density that can be obtained for lithium aluminosilicate glass under salt bath conditions in an extreme experiment and the bifurcation threshold of the glass of that formula, glass stock sheets of different formulas can be rapidly screened to determine whether they are suitable for preparing tempered glass with both high stress and high individual strength that meets the requirements of the present invention. Furthermore, the present invention provides a suitable two-step strengthening process for the glass stock sheets corresponding to the screened glass stock sheet formula. The strengthening process provided by the present invention can reduce the strengthening time, especially the strengthening time for the second step of ion exchange chemical strengthening. While achieving high stress performance, it can ensure that the strengthened glass still has excellent individual strength.

Description

Technical Field

[0001] The present invention relates to the technical field of glass, and in particular to a preparation method of tempered glass having both high stress and high monomer strength, and the tempered 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 produce 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 guarantee that lithium aluminum silicate chemically strengthened glass that meets the requirements will be obtained. The reason for this 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 optimal strengthening process for the specific formula glass sheet, which often leads to over-strengthening or under-strengthening, resulting in product waste.

[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 tempered glass with both high stress 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 the glass stock must meet when preparing chemically strengthened glass with both high stress performance 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 two-step strengthening process for the glass stock corresponding to the screened glass stock formulations. The strengthening process provided by the present invention can reduce the strengthening time, especially the strengthening time of the second step, ion exchange chemical strengthening. While achieving high stress performance, 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 primarily large fragments, thus meeting the needs of emergency use.

[0006] The present invention provides a method for preparing tempered glass having both high stress and high monomer strength, comprising the following steps:

[0007] S1. Screening out a glass formula suitable for preparing tempered glass with both high stress and high monomer strength, and using the glass formula as the original glass sheet to be tempered. 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 glass with a difference of bifurcation threshold greater than or equal to 3000 MPa / mm, determine the corresponding glass formula, and use the glass with this formula as the original glass sheet to be strengthened;

[0010] S2. The glass sheets to be strengthened selected in S1 are subjected to two-step ion exchange chemical strengthening. By controlling the process conditions of the two-step ion exchange chemical strengthening, strengthened glass with both high stress and high monomer strength can be produced.

[0011] Further, in S2, according to CT_LD max1The difference between the bifurcation threshold and the glass is used to control the process conditions of the first step of ion exchange chemical strengthening so that the glass obtained after the first step of ion exchange satisfies the following conditions: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first step of ion exchange, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500 to 4000 MPa / mm.

[0012] Furthermore, in S2,

[0013] When CT_LD max1 When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 0 wt% and less than 20 wt% of sodium nitrate, greater than 80 wt% and less than 100 wt% of potassium nitrate, and 300 to 1,000 ppm of lithium ions, and the salt bath temperature is 420 to 500° C.;

[0014] When CT_LD max1 When the difference minus the bifurcation threshold is 8,000 to 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 50 wt% and less than 100 wt% of potassium nitrate and greater than 0 wt% and less than 50 wt% of sodium nitrate, and the salt bath temperature is 420 to 500° C.;

[0015] When CT_LD max1 When the difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm, the salt bath used for the first step of ion exchange on the glass sheet includes 0wt% to 20wt% potassium nitrate and 80wt% to 100wt% sodium nitrate, and the salt bath temperature is 420 to 500°C.

[0016] Furthermore, in S2, when CT_LD max1 When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first step of ion exchange of the glass sheet includes greater than or equal to 5 wt% and less than 20 wt% of sodium nitrate, greater than 80 wt% and less than or equal to 95 wt% of potassium nitrate, and 300 to 1,000 ppm of lithium ions.

[0017] Furthermore, in S2, when CT_LD max1 When the difference minus the bifurcation threshold is 8000-20000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes more than 50wt% and less than or equal to 75wt% of potassium nitrate and more than or equal to 25wt% and less than 50wt% of sodium nitrate.

[0018] Furthermore, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange satisfies:

[0019] 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;

[0020] b. Surface compressive stress CS is greater than 800MPa.

[0021] Furthermore, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange further satisfies:

[0022] c. The compressive stress depth DOL_0 is greater than 16.00% of the thickness of the obtained lithium aluminum silicate chemically strengthened glass.

[0023] Furthermore, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange further satisfies:

[0024] d. CS 50 Satisfies the formula:

[0025] 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.

[0026] Furthermore, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange further satisfies:

[0027] 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.

[0028] Furthermore, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange further satisfies:

[0029] 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.

[0030] Furthermore, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange further satisfies:

[0031] 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.

[0032] Furthermore, in S2, the salt bath used for the second step ion exchange of the glass sheet includes 95wt% to 100wt% of potassium nitrate and 0 to 5wt% of sodium nitrate, and the salt bath temperature is 400 to 500°C.

[0033] The present invention also provides a lithium aluminum silicon chemically strengthened glass, which is prepared by the above-mentioned preparation method.

[0034] 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.

[0035] Furthermore, the compressive stress depth DOL_0 of the strengthened glass is greater than 16.00% of the thickness of the strengthened glass.

[0036] Furthermore, the CS of the tempered glass 50 Satisfies the formula:

[0037] 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.

[0038] 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

[0039] The surface compressive stress CS of the tempered glass is greater than or equal to 850 MPa.

[0040] 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

[0041] The tempered glass has a four-point bending strength greater than 700 MPa when converted to a thickness of 0.7 mm.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] The present invention also provides an electronic terminal as a consumer product, comprising:

[0046] a housing comprising a front surface, a rear surface, and side surfaces;

[0047] 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;

[0048] The front surface or / and rear surface or / and side surface comprises lithium aluminum silicon chemically strengthened glass prepared by the above preparation method;

[0049] 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;

[0050] The electronic terminals as consumer products include mobile phones, tablet computers, photovoltaic devices, or other electronic terminals (such as electronic watches, etc.).

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 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 for lithium aluminosilicate glass in the salt bath conditions of the extreme experiment (a 100wt% sodium nitrate salt bath 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 and high monomer strength that meets the requirements of the present invention. This also provides a basis for optimizing the subsequent chemical strengthening process, 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 achieve 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.

[0053] 2. The inventors of the present invention have provided a suitable two-step strengthening process for glass sheets corresponding to the selected glass sheet formulations. The inventors discovered that by strictly controlling the process conditions of the first ion exchange step, the glass sheet can be guaranteed to meet specific performance requirements after the first ion exchange step. Specifically, the glass obtained after the first ion exchange step meets the following requirements: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first ion exchange step, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500-4000 MPa / mm. This effectively avoids insufficient strengthening during the first step, which can lead to low stress performance in the final strengthened glass product, inability to fully achieve anti-destructive strength, and poor drop resistance. It also effectively avoids the problem of increased strengthening time in the second step due to overstrengthening during the first step, thereby reducing the strengthening time of the second ion exchange chemical strengthening step. By reducing the strengthening time of the second step, it is possible to avoid problems such as increased volume expansion of the strengthened glass product, increased surface microcracks, and increased risk of high-temperature salt bath corrosion on the glass surface, thereby preventing the resulting decrease in the strength performance of the final strengthened glass product. That is, by adopting the two-step strengthening process of the present invention, while achieving high stress performance, it can ensure that the strengthened glass still has excellent individual strength, and it can also ensure that the fragments produced by the strengthened glass after immediate breakage are mainly large fragments, so as to meet the needs of emergency use.

[0054] In addition, the present invention shortens the strengthening time by providing a suitable two-step strengthening process, and can also reduce the content of lithium ions precipitated in the salt bath, thereby ensuring the service life of the salt bath. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a test diagram of the sandpaper drop resistance height;

[0056] Figure 2 It is a diagram of glass breakage patterns;

[0057] Figure 3 It is a test diagram of the drop height of the falling ball;

[0058] Figure 4 This is a schematic diagram of the nine points on the sample surface to be impacted during the ball drop height test;

[0059] Figure 5 It is a schematic diagram of the four-point bending strength test;

[0060] Figure 6 This is a photograph showing the fracture of the tempered glass product of Example 1 after a sandpaper drop test. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0062] 1. The relevant special names and related measurement methods involved in the present invention are explained as follows:

[0063] (1) Original glass: glass that has not been chemically strengthened by ion exchange.

[0064] (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.

[0065] (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.

[0066] (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.

[0067] (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).

[0068] 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.

[0069] (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.

[0070] 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.

[0071] 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.

[0072] (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 .

[0073] 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 .

[0074] 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 .

[0075] (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 bifurcates, the tensile stress linear density of the strengthened glass sample is the bifurcation threshold.

[0076] Bifurcation threshold test method:

[0077] 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.

[0078] 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.

[0079] 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 .

[0080] (10) Ball drop resistance test method:

[0081] 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.

[0082] (11) Four-point bending strength test method:

[0083] 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.

[0084] 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.

[0085] (12) Sandpaper drop resistance test method:

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 2. A method for preparing tempered glass with both high stress and high monomer strength.

[0090] This embodiment provides a method for preparing tempered glass having both high stress and high monomer strength, comprising the following steps:

[0091] S1. Screening out a glass formula suitable for preparing tempered glass with both high stress and high monomer strength, and using the glass formula as the original glass sheet to be tempered. The specific steps include:

[0092] (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;

[0093] (2) Screen out the bifurcation threshold greater than 40000MPa / mm and CT_LD max1 For glasses with a difference of 3000 MPa / mm minus the bifurcation threshold, the corresponding glass formula is determined, and the glass with this formula is used as the glass sheet to be strengthened. Since the bifurcation threshold is a reference indicator for the glass's ability to safely accommodate stress, it is an inherent characteristic of the glass sheet itself and does not change with changes in the glass strengthening conditions, but only with changes in the glass formula. Therefore, the bifurcation threshold becomes a characteristic parameter for determining whether the glass sheet meets the requirements for preparing high-stress strengthened glass.

[0094] S2. The glass sheets to be strengthened selected in S1 are subjected to two-step ion exchange chemical strengthening. By controlling the process conditions of the two-step ion exchange chemical strengthening, strengthened glass with both high stress and high monomer strength can be produced.

[0095] 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.

[0096] Through in-depth and systematic research on glass sheets 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 accommodate 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 sheet must meet certain characteristic requirements, namely, the bifurcation threshold of the glass sheet must be greater than 40,000 MPa / mm, and the maximum tensile stress linear density CT_LD obtained by the glass sheet in a 100wt% sodium nitrate salt bath at 450°C must be greater than 40,000 MPa / mm. max1 The difference minus the bifurcation threshold must be greater than or equal to 3000 MPa / mm. The glass raw material formula selected according to this characteristic requirement meets the requirements for preparing high-stress performance tempered glass.

[0097] 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.

[0098] In certain embodiments, the bifurcation threshold of the glass sheet corresponding to the screened glass formula includes the following ranges:

[0099] 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.

[0100] 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 max1 The 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.

[0101] 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.

[0102] In this embodiment, in S2, according to CT_LD max1The difference between the bifurcation threshold and the glass is used to control the process conditions of the first step of ion exchange chemical strengthening so that the glass obtained after the first step of ion exchange satisfies the following conditions: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first step of ion exchange, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500 to 4000 MPa / mm.

[0103] The first step of the ion exchange chemical strengthening process is mainly a sodium-lithium ion exchange process. This strengthening process will provide sufficient stress layer depth for the lithium aluminosilicate glass original sheet, and uses a 100wt% sodium nitrate salt bath or a mixed salt bath of sodium nitrate and potassium nitrate. After research, the inventors found that in order to ensure that the tensile stress linear density of the strengthened glass product obtained after the two-step strengthening is large enough, and the difference between the tensile stress linear density and the bifurcation threshold is within a safe range (to avoid the generation of a large number of small fragments), and at the same time ensure that the strength performance of the glass monomer after the two-step strengthening is excellent, it is necessary to strictly control the process conditions of the first step of ion exchange, including the salt bath composition and salt bath temperature. Because the stress characteristics obtained by the lithium aluminosilicate glass after the first step of ion exchange chemical strengthening have an important influence on the subsequent strengthening process and the final strengthening effect.

[0104] If, after the first strengthening step, the tensile stress linear density (CT_LD1) of the glass barely reaches the bifurcation threshold, or the difference between CT_LD1 and the bifurcation threshold is within 1500 MPa / mm, the second strengthening step, primarily based on potassium-sodium exchange, will weaken the tensile stress linear density generated in the first strengthening step, further reducing it and preventing the resulting tempered glass from achieving optimal drop resistance. However, if the difference between the tensile stress linear density (CT_LD1) and the bifurcation threshold after the first strengthening step exceeds 4000 MPa / mm, significantly exceeding the bifurcation threshold, the glass will become unstable. A second, longer strengthening step will be required to reduce the high tensile stress linear density generated in the first strengthening step and keep the difference between the tensile stress linear density and the bifurcation threshold within a safe range. This will prevent the resulting tempered glass from producing a large number of small fragments upon breakage. However, increasing the duration of the second-step ion exchange chemical strengthening process can lead to increased glass volume expansion and surface microcracks, significantly reducing the individual properties of the strengthened glass, such as ball drop resistance and four-point bending performance. Furthermore, prolonged high-temperature strengthening increases the risk of high-temperature salt bath corrosion on the glass surface. Furthermore, increasing the duration of the second-step ion exchange chemical strengthening process can also lead to increased lithium ion precipitation, shortening the lifespan of the salt bath.

[0105] By strictly controlling the process conditions of the first ion exchange step, the present invention ensures that the glass obtained after the first ion exchange step meets specific performance requirements. Specifically, the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first ion exchange step, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is between 1500 and 4000 MPa / mm. This effectively avoids the low stress performance, inability to fully develop the anti-destructive strength, and poor drop resistance of the final strengthened glass product caused by insufficient strengthening during the first step. It also effectively avoids the problem of increased strengthening time in the second step due to excessive strengthening during the first step, thereby reducing the strengthening time of the second ion exchange chemical strengthening step. By reducing the strengthening time of the second step, it can also avoid problems such as increased volume expansion, increased surface microcracks, and increased risk of glass surface erosion in the strengthened glass product, thereby preventing the resulting reduced strength of the final strengthened glass product. In other words, by adopting the two-step strengthening process of the present invention, while achieving high stress performance, the strengthened glass can still maintain excellent strength in its own right. It also ensures that the fragments produced after the strengthened glass immediately breaks are primarily large fragments, meeting the needs of emergency use. In addition, the present invention shortens the strengthening time by providing a suitable two-step strengthening process, and can also reduce the content of lithium ions precipitated in the salt bath, thereby ensuring the service life of the salt bath.

[0106] In an embodiment, according to CT_LD max1 The difference between the value of the bifurcation threshold and the value of the glass bifurcation threshold controls the process conditions of the first step of ion exchange chemical strengthening so that the glass obtained after the first step of ion exchange satisfies:

[0107] 1) The compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first ion exchange. For example, the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first ion exchange, greater than or equal to 15.50% of the thickness of the glass obtained after the first ion exchange, greater than or equal to 16.00% of the thickness of the glass obtained after the first ion exchange, greater than or equal to 16.50% of the thickness of the glass obtained after the first ion exchange, greater than or equal to 17.00% of the thickness of the glass obtained after the first ion exchange, greater than or equal to 17.50% of the thickness of the glass obtained after the first ion exchange, or greater than or equal to 18.00% of the thickness of the glass obtained after the first ion exchange. It should be understood that in embodiments, any of the above ranges may be combined with any other ranges.

[0108] 2) The difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500-4000 MPa / mm. For example, the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500 MPa / mm, 1600 MPa / mm, 1700 MPa / mm, 1800 MPa / mm, 1900 MPa / mm, 2000 MPa / mm, 2100 MPa / mm, 2200 MPa / mm, 2300 MPa / mm, 2400 MPa / mm, 2500 MPa / mm, 2600 MPa / mm, 2700 MPa / mm, 2800 MPa / mm, 2900 MPa / mm, 3000 MPa / mm, 3100 MPa / mm, 3200 MPa / mm, 3300 MPa / mm, 3400 MPa / mm, 3500 MPa / mm, 3600 MPa / mm, 3700 MPa / mm, 3900 MPa / mm, and 4000 MPa / mm. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges. In certain embodiments, the difference range of the tensile stress linear density CT_LD1 minus the bifurcation threshold includes: 1500-2000 MPa / mm, 1600-2100 MPa / mm, 1800-2000 MPa / mm, 1900-2300 MPa / mm, 2000-2600 MPa / mm, 2000-2900 MPa / mm, 2500-2800 MPa / mm, 2300-2600 MPa / mm, 2900-3100 MPa / mm, 2800-3000 MPa / mm , 3000-3500 MPa / mm, 2700-3200 MPa / mm, 3500-3800 MPa / mm, 3100-3600 MPa / mm, 1900-4000 MPa / mm, 2000-4000 MPa / mm, 2500-4000 MPa / mm, 3500-4000 MPa / mm, 2500-3900 MPa / mm, 1500-3700 MPa / mm, 1500-3400 MPa / mm, and all ranges and subranges between the above values.

[0109] In order to ensure that the glass obtained after the first step of ion exchange chemical strengthening meets the specific performance requirements, that is, the glass obtained after the first step of ion exchange meets the following requirements: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first step of ion exchange, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500 to 4000 MPa / mm, the present invention is based on CT_LD max1 The difference from the bifurcation threshold is used to adjust the first step ion exchange strengthening process of the glass sheet, providing the optimal strengthening salt bath conditions and temperature conditions. max1The reason why the first step of ion exchange strengthening process is adjusted by the difference between the bifurcation threshold and the value of the first step of ion exchange strengthening process is that the purpose of the first step of ion exchange chemical strengthening process is mainly to form a larger compressive stress depth in the glass and control the tensile stress linear density CT_LD1 within a certain range. However, for some glass formulations, its CT_LD max1 Very high. If the salt bath conditions used in the first step of ion exchange are not appropriate, when the compressive stress depth obtained by glass strengthening reaches the requirement, the tensile stress line density of the glass is already far higher than the bifurcation threshold, and cannot meet the control requirement that the difference between the tensile stress line density CT_LD1 and the bifurcation threshold is 1500-4000MPa / mm. Therefore, the salt bath conditions used in the first step of ion exchange need to be adjusted according to the CT_LD of the glass. max1 to adjust the control.

[0110] In this embodiment, in S2,

[0111] When CT_LD max1 When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 0 wt% and less than 20 wt% of sodium nitrate, greater than 80 wt% and less than 100 wt% of potassium nitrate, and 300 to 1,000 ppm of lithium ions, and the salt bath temperature is 420 to 500° C.;

[0112] When CT_LD max1 When the difference minus the bifurcation threshold is 8,000 to 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 50 wt% and less than 100 wt% of potassium nitrate and greater than 0 wt% and less than 50 wt% of sodium nitrate, and the salt bath temperature is 420 to 500° C.;

[0113] When CT_LD max1 When the difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm, the salt bath used for the first step of ion exchange on the glass sheet includes 0wt% to 20wt% potassium nitrate and 80wt% to 100wt% sodium nitrate, and the salt bath temperature is 420 to 500°C.

[0114] In an embodiment, in S2, when CT_LD max1When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 0wt% and less than 20wt% of sodium nitrate, greater than 80wt% and less than 100wt% of potassium nitrate, and 300-1000ppm of lithium ions, and the salt bath temperature is 420-500°C; preferably, the salt bath used for the first ion exchange of the glass sheet includes greater than or equal to 5wt% and less than 20wt% of sodium nitrate, greater than 80wt% and less than or equal to 95wt% of potassium nitrate, and 300-1000ppm of lithium ions.

[0115] The duration of the first ion exchange chemical strengthening of the glass substrate is related to the salt bath composition, salt bath temperature, glass thickness, and glass formulation. The properties of the glass obtained after the first step of strengthening are tested periodically (herein, the glass is removed from the salt bath for testing at regular intervals (e.g., 1 hour, 0.5 hours, etc.). If the test fails, it is placed in the salt bath for further strengthening). When the glass obtained after the first step of ion exchange chemical strengthening meets the following conditions: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first step of ion exchange, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is between 1500 and 4000 MPa / mm, the first step of ion exchange chemical strengthening is terminated. The strengthening time and salt bath conditions used for strengthening (including salt bath composition and temperature) are recorded. The recorded strengthening time can be used when strengthening glass substrates with the same formulation and thickness under the same salt bath conditions in the future.

[0116] Here "When CT_LD max1 The difference minus the bifurcation threshold is greater than 20000 MPa / mm” includes: when CT_LD max1 The difference minus the bifurcation threshold is greater than 20,000 MPa / mm, greater than 25,000 MPa / mm, greater than 30,000 MPa / mm, greater than 35,000 MPa / mm, greater than 40,000 MPa / mm, greater than 45,000 MPa / mm, greater than 55,000 MPa / mm, greater than 50,000 MPa / mm, etc. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0117] In an embodiment, when CT_LD max1 When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes more than 0 wt% and less than 20 wt% of sodium nitrate, more than 80 wt% and less than 100 wt% of potassium nitrate, and 300 to 1,000 ppm of lithium ions.

[0118] For example, the salt bath of various embodiments may include greater than 0 wt% and less than 20 wt%, greater than 0 wt% and less than 18 wt%, greater than 0 wt% and less than 16 wt%, greater than 0 wt% and less than 15 wt%, greater than 0 wt% and less than 12 wt%, greater than 0 wt% and less than 10 wt%, greater than 0 wt% and less than 8 wt%, greater than 0 wt% and less than 6 wt%, greater than 5 wt% and less than 20 wt%, greater than 5 wt% and less than 18 wt%, greater than 5 wt% and less than 16 wt%, greater than 5 wt% and less than 15 wt%, greater than 5 wt% and less than 12 wt%, greater than 5 wt% and less than 10 wt%, greater than 5 wt% and less than 8 wt%, greater than 5 wt% and less than 6 wt% sodium nitrate, based on the total amount of sodium nitrate (NaNO3) and potassium nitrate (KNO3) in the salt bath, or any and all subranges formed from any of these endpoints.

[0119] 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 80 wt% and less than 100 wt%, greater than 82 wt% and less than 100 wt%, greater than 84 wt% and less than 100 wt%, greater than or equal to 85 wt% and less than 100 wt%, greater than 88 wt% and less than 100 wt%, greater than 90 wt% and less than 100 wt%, greater than 92 wt% and less than 100 wt%, greater than 94 wt% and less than 100 wt%, and greater than 100 wt%. % and less than 86 wt%, greater than 80 wt% and less than 84 wt%, greater than 80 wt% and less than 82 wt% potassium nitrate, or any and all subranges formed from any of these endpoints.

[0120] The salt baths of various embodiments may further include 300-1000 ppm, 300-900 ppm, 300-800 ppm, 300-700 ppm, 300-600 ppm, 300-500 ppm, 300-400 ppm, 300-550 ppm, 300-650 ppm of lithium ions, or any and all subranges formed from any of these endpoints, based on the total weight of the salt in the salt bath. The lithium ions are introduced via lithium nitrate.

[0121] The first step ion exchange salt bath temperature of various embodiments can be 420-500°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, 420-450°C, 430-460°C, 460-490°C, 470-500°C, or any and all subranges formed from any of these endpoints.

[0122] In an embodiment, in S2, when CT_LD max1 When the difference minus the bifurcation threshold is 8000 to 20000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 50wt% and less than 100wt% of potassium nitrate and greater than 0wt% and less than 50wt% of sodium nitrate, and the salt bath temperature is 420 to 500°C; preferably, the salt bath used for the first ion exchange of the glass sheet includes greater than 50wt% and less than or equal to 75wt% of potassium nitrate and greater than or equal to 25wt% and less than 50wt% of sodium nitrate.

[0123] Here "When CT_LD max1 The difference minus the bifurcation threshold is 8000~20000MPa / mm" includes: CT_LD max1 The difference minus the bifurcation threshold is 8000-8500MPa / mm, 8500-9000MPa / mm, 9000-9500MPa / mm, 9500-10000MPa / mm, 10000-15000MPa / mm, 8000-9700MPa / mm, 8500-12000MPa / mm, 8800-13000MPa / mm MPa / mm, 9000-14000 MPa / mm, 9000-18000 MPa / mm, 9500-17000 MPa / mm, 9400-18000 MPa / mm, 8700-1100 MPa / mm, 8900-12000 MPa / mm, 8600-15000 MPa / mm, 8000-20000 MPa / mm, etc. It should be understood that in embodiments, any of the above ranges may be combined with any other ranges.

[0124] In an embodiment, when CT_LD max1 When the difference minus the bifurcation threshold is 8000-20000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes more than 50 wt % and less than 100 wt % of potassium nitrate and more than 0 wt % and less than 50 wt % of sodium nitrate.

[0125] For example, based on the total amount of sodium nitrate (NaNO3) and potassium nitrate (KNO3) in the salt bath, the salt bath of various embodiments may include greater than 0 wt% and less than 50 wt%, greater than 0 wt% and less than 45 wt%, greater than 0 wt% and less than 40 wt%, greater than 0 wt% and less than or equal to 36 wt%, greater than 0 wt% and less than 35 wt%, greater than 0 wt% and less than 30 wt%,

[0126] 25 wt% to less than 50 wt%, 25 wt% to less than 45 wt%, 25 wt% to less than 42 wt%, 25 wt% to less than 40 wt%, 25 wt% to less than 36 wt%, 25 wt% to less than 32 wt%, 25 wt% to less than 30 wt%, 25 wt% to less than 28 wt% sodium nitrate, or any and all subranges formed from any of these endpoints.

[0127] The salt bath of various embodiments may include greater than 50 wt% and less than 100 wt%, greater than 55 wt% and less than 100 wt%, greater than 60 wt% and less than 100 wt%, greater than 64 wt% and less than 100 wt%, greater than 65 wt% and less than 100 wt%, greater than 70 wt% and less than 100 wt%, greater than 50 wt% and less than 75 wt%, greater than 50 wt% and less than 72 wt%, greater than 50 wt% and less than 70 wt%, greater than 50 wt% and less than 68 wt%, greater than 50 wt% and less than 64 wt%, greater than 50 wt% and less than 60 wt%, greater than 50 wt% and less than 55 wt% potassium nitrate, 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.

[0128] The first step ion exchange salt bath temperature of various embodiments can be 420-500°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, 420-450°C, 430-460°C, 460-490°C, 470-500°C, or any and all subranges formed from any of these endpoints.

[0129] In an embodiment, in S2, when CT_LD max1When the difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm, the salt bath used for the first step of ion exchange on the glass sheet includes 0wt% to 20wt% potassium nitrate and 80wt% to 100wt% sodium nitrate, and the salt bath temperature is 420 to 500°C.

[0130] Here "When CT_LD max1 The difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm" includes: CT_LD max1 The difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm, greater than or equal to 3000 MPa / mm and less than 7500 MPa / mm, greater than or equal to 3000 MPa / mm and less than 7000 MPa / mm, greater than or equal to 3000 MPa / mm and less than 6500 MPa / mm, greater than or equal to 3000 MPa / mm and less than 6000 MPa / mm, greater than or equal to 3000 MPa / mm and less than 5500 MPa / mm, greater than or equal to 3000 MPa / mm and less than 5000 MPa / mm, greater than or equal to 3000 MPa / mm and less than 4500 MPa / mm, greater than or equal to 3000 MPa / mm and less than 4000 MPa / mm, greater than or equal to 3000 MPa / mm and less than 3000 MPa / mm. The above ranges are preferably between 3500 MPa / mm and less than 8000 MPa / mm, between 3500 MPa / mm and less than 8000 MPa / mm, between 4000 MPa / mm and less than 8000 MPa / mm, between 4500 MPa / mm and less than 8000 MPa / mm, between 5000 MPa / mm and less than 8000 MPa / mm, between 5500 MPa / mm and less than 8000 MPa / mm, between 6000 MPa / mm and less than 8000 MPa / mm, between 6500 MPa / mm and less than 8000 MPa / mm, between 7000 MPa / mm and less than 8000 MPa / mm, and between 7500 MPa / mm and less than 8000 MPa / mm. It should be understood that, in embodiments, any of the above ranges may be combined with any other ranges.

[0131] In an embodiment, when CT_LD max1 When the difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes 0wt% to 20wt% potassium nitrate and 80wt% to 100wt% sodium nitrate.

[0132] For example, the salt bath of various embodiments may include 80 wt% to 100 wt%, 85 wt% to 100 wt%, 90 wt% to 100 wt%, 95 wt% to 100 wt%, 99 wt% to 100 wt%, 80 wt% to 99 wt%, 80 wt% to 95 wt%, 80 wt% to 92 wt%, 80 wt% to 90 wt%, 80 wt% to 88 wt%, 80 wt% to 85 wt%, 80 wt% to 82 wt% sodium nitrate, 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.

[0133] 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 0wt% to 20wt%, 0wt% to 18wt%, 0wt% to 16wt%, 0wt% to 14wt%, 0wt% to 12wt%, 0wt% to 10wt%, 0wt% to 8wt%, 0wt% to 7wt%, 0wt% to 6wt%, 0wt% to 5wt%, 0wt% to 4wt%, 0wt% to 3wt%, 0wt% to 2wt%, 0wt% to 10wt% and 0wt% to 10wt%. % to 20 wt%, 14 wt% to 20 wt%, 16 wt% to 20 wt%, 18 wt% to 20 wt% potassium nitrate, or any and all subranges formed from any of these endpoints.

[0134] The first step ion exchange salt bath temperature of various embodiments can be 420-500°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, 420-450°C, 430-460°C, 460-490°C, 470-500°C, or any and all subranges formed from any of these endpoints.

[0135] After the first ion exchange, the obtained glass is subjected to the second ion exchange. The second ion exchange is a potassium-sodium ion exchange process, mainly using a 100wt% potassium nitrate salt bath or a mixed salt bath of sodium nitrate and potassium nitrate. Since the first ion exchange has been effectively controlled to ensure that the glass meets specific performance requirements, the strengthening time of the second ion exchange can be well controlled. This can reduce the stress relaxation of the CS under high temperature conditions during the second strengthening (i.e., the second ion exchange). 50 This reduces the weakening effect of the glass, while also preventing problems such as increased glass volume expansion and surface microcracks caused by prolonged secondary strengthening. It also prevents a significant decrease in the individual properties of the tempered glass product, such as ball drop resistance and four-point bending performance, and reduces the risk of high-temperature salt bath corrosion on the glass surface. Furthermore, it effectively controls the amount of lithium ion precipitation during the second strengthening step, ensuring the service life of the salt bath.

[0136] In this embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange satisfies:

[0137] 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;

[0138] b. Surface compressive stress CS is greater than 800MPa.

[0139] In an embodiment, in S2, the process conditions of the second step ion exchange chemical strengthening are controlled so that the bifurcation threshold of the lithium aluminum silicate chemically strengthened glass obtained after the second step 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 second step ion exchange chemical strengthening are controlled so that the bifurcation threshold of the lithium aluminum silicate chemically strengthened glass obtained after the second step ion exchange has a value range including:

[0140] 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.

[0141] In an embodiment, in S2, the process conditions of the second step ion exchange chemical strengthening are controlled so that the tensile stress linear density CT_LD of the lithium aluminum silicate chemically strengthened glass obtained after the second step 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 second step ion exchange chemical strengthening are controlled so that the tensile stress linear density CT_LD of the lithium aluminum silicate chemically strengthened glass obtained after the second step ion exchange has a value range including:

[0142] 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.

[0143] In an embodiment, in S2, the process conditions of the second step ion exchange chemical strengthening 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 second step ion exchange minus the bifurcation threshold includes -3000MPa / mm~3000MPa / mm, -2000MPa / mm~3000MPa / mm, -1000MPa / mm~3000MPa / mm, 0MPa / mm~3000MPa / mm, -2500MPa / mm~0MPa / mm, -2000MPa / mm~ 1000 MPa / mm, -1000 MPa / mm to 2000 MPa / mm, -2500 MPa / mm to 1000 MPa / mm, 0 MPa / mm to 1000 MPa / mm, 0 MPa / mm to 2000 MPa / mm, -2500 MPa / mm to 2500 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 second step of ion exchange chemical strengthening are controlled so that the difference between the tensile stress linear density CT_LD of the lithium aluminosilicate chemically strengthened glass obtained after the second step of ion exchange minus 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.

[0144] In an embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the surface compressive stress CS of the lithium aluminosilicate chemically strengthened glass obtained after the second step of 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 an embodiment, any of the above ranges may be combined with any other ranges. In certain embodiments, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the surface compressive stress CS of the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange has a value range including: 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.

[0145] In this embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange further satisfies the following conditions:

[0146] c. The compressive stress depth DOL_0 is greater than 16.00% of the thickness of the obtained lithium aluminum silicate chemically strengthened glass.

[0147] In an embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the compressive stress depth DOL_0 of the lithium aluminosilicate chemically strengthened glass obtained after the second step of ion exchange is greater than 16.00% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass, greater than 16.50% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass, greater than 17.00% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass, greater than 17.50% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass, greater than 18.00% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass, greater than 18.50% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass, or greater than 19.00% of the thickness of the obtained lithium aluminosilicate chemically strengthened glass. It should be understood that in an embodiment, any of the above ranges can be combined with any other ranges.

[0148] In this embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange further satisfies the following conditions:

[0149] d. CS 50 Satisfies the formula:

[0150] 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.

[0151] In the embodiment, in S2, the process conditions of the second step ion exchange chemical strengthening are controlled so that the CS of the lithium aluminum silicate chemically strengthened glass obtained after the second step ion exchange is converted to a thickness of 0.7 mm. 50 The range is between 100 and 220 MPa.

[0152] 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.

[0153] In this embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange further satisfies the following conditions:

[0154] 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.

[0155] 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.

[0156] In this embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange further satisfies the following conditions:

[0157] 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.

[0158] 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.

[0159] In this embodiment, in S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange further satisfies the following conditions:

[0160] 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.

[0161] 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.

[0162] In this embodiment, in S2, the salt bath used for the second step ion exchange of the glass sheet includes 95wt% to 100wt% potassium nitrate and 0 to 5wt% sodium nitrate, and the salt bath temperature is 400 to 500°C.

[0163] The time it takes to perform the second ion exchange on the glass is related to the properties of the glass obtained after the first ion exchange, the glass thickness, the glass formula, and the salt bath composition and temperature of the second ion exchange. By regularly testing the performance of the glass after the second step of strengthening, when the strengthened glass meets the required performance requirements for the strengthened glass product, the second ion exchange is stopped. The strengthening time of the second ion exchange, the salt bath conditions (salt bath composition and temperature) of the second ion exchange, and the process conditions used in the first ion exchange (salt bath composition, temperature, and strengthening time) are recorded. When the second step of strengthening is performed on glass with the same formula and thickness under the same salt bath conditions, the recorded first ion exchange process conditions, second salt bath conditions, and strengthening time of the second ion exchange can be used.

[0164] In an embodiment, in S2, the salt bath used for the second step ion exchange of the glass raw sheet includes 95 wt% to 100 wt% of potassium nitrate and 0 to 5 wt% of sodium nitrate.

[0165] For example, the salt bath of various embodiments may include 95 wt% to 100 wt%, 96 wt% to 100 wt%, 97 wt% to 100 wt%, 98 wt% to 100 wt%, 99 wt% to 100 wt%, 95 wt% to 99 wt%, 95 wt% to 98 wt%, 95 wt% to 97 wt%, 95 wt% to 96 wt% potassium nitrate, 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.

[0166] The salt baths of various embodiments may include 0-5 wt%, 0-4 wt%, 0-3 wt%, 0-2 wt%, 0-1 wt%, 1-5 wt%, 2-5 wt%, 3-5 wt%, 4-5 wt% sodium nitrate 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.

[0167] The second step ion exchange salt bath temperature of various embodiments can be 400-450°C, 410-420°C, 420-430°C, 430-440°C, 440-450°C, 450-460°C, 460-470°C, 470-480°C, 480-490°C, 490-500°C, 425-450°C, 435-455°C, 445-470°C, 430-460°C, 460-490°C, 470-500°C, etc., or any and all subranges formed by any of these endpoints.

[0168] 3. A lithium aluminum silicon chemically strengthened glass with both high stress and high single strength.

[0169] 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.

[0170] In an embodiment, the compressive stress depth DOL_0 of the strengthened glass is greater than 16.00% of the thickness of the strengthened glass.

[0171] In an embodiment, the CS of the tempered glass 50 Satisfies the formula:

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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 23.4 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 1 produced mainly large fragments when it was broken.

[0178] 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.

[0179] The lithium aluminum silicate chemically strengthened glass 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 automobiles, 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.

[0180] 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.

[0181] 4. An electronic terminal as a consumer product.

[0182] This embodiment further provides an electronic terminal as a consumer product, including:

[0183] a housing comprising a front surface, a rear surface, and side surfaces;

[0184] 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;

[0185] The front surface or / and rear surface or / and side surface comprises lithium aluminum silicon chemically strengthened glass prepared by the above preparation method;

[0186] 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;

[0187] The electronic terminals as consumer products include mobile phones, tablet computers, photovoltaic devices, or other electronic terminals (such as electronic watches, etc.).

[0188] 5. The present invention will be described below through specific embodiments.

[0189] Table 1 shows the properties of the glass sheets corresponding to the glass formulations of glass 1 to 6.

[0190]

[0191] Table 2 shows the properties of the glass sheets corresponding to the glass formulations 7 to 9 and comparative formulations 1 to 2.

[0192]

[0193] 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 .

[0194] 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.

[0195] Table 3 shows the strengthening process conditions used in Examples 1-3 and the properties of the tempered glass obtained.

[0196]

[0197]

[0198] Note: 1. “420℃*100wt%KNO3*1h” means strengthening in a 100wt% KNO3 salt bath at 420℃ for 1h. Other similar expressions have similar meanings.

[0199] 2. After chemical strengthening, the thickness of the original glass sheet hardly changes. The difference between the thickness of the original glass sheet, the thickness of the glass obtained by the first ion exchange chemical strengthening, and the thickness of the lithium aluminum silicate chemically strengthened glass obtained by the second ion exchange chemical strengthening is very small, within 10 microns, and is almost negligible. Therefore, when calculating the ratio of DOL_1 to the thickness of the glass obtained by the first ion exchange step, and the ratio of DOL_0 to the thickness of the lithium aluminum silicate chemically strengthened glass obtained by the second ion exchange step, DOL_1 and DOL_0 can be directly divided by the thickness of the original glass sheet.

[0200] 3. DOL_0 refers to the distance from any surface of the lithium aluminum silicate chemically strengthened glass obtained after the second step of ion exchange chemical strengthening to the position where the compressive stress is zero;

[0201] Compressive stress depth DOL_1: refers to the distance from any surface of the glass obtained after the first step of ion exchange chemical strengthening to the position where the compressive stress is zero;

[0202] CT_LD1: refers to the tensile stress linear density of the glass obtained after the first step of ion exchange chemical strengthening; CT_LD refers to the tensile stress linear density of the lithium aluminum silicon chemically strengthened glass obtained after the second step of ion exchange chemical strengthening.

[0203] Table 4 shows the strengthening process conditions used in Comparative Examples 1-2 and the properties of the tempered glass obtained.

[0204]

[0205]

[0206] From the comparison of Table 3 and Table 4, it can be seen that by screening glass raw sheets and matching the strengthening process according to the preparation method provided by the present invention, lithium aluminum silicon chemically strengthened glass with both high stress performance and high monomer strength performance can be prepared.

[0207] In Examples 1 to 3, the bifurcation threshold is selected to be greater than 40000 MPa / mm, and CT_LD max1 The glass with a difference of 3000MPa / mm minus the bifurcation threshold is used as the original glass to be strengthened, and then according to CT_LD max1 By using different salt baths in the first ion exchange step, the resulting glass meets the following requirements: compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first ion exchange step, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is between 1500 and 4000 MPa / mm. Ultimately, the chemically strengthened glass products produced after the two-step strengthening process in Examples 1-3 achieved high CT_LD, DOL_0, CS, four-point bending strength, ball drop height, and sandpaper drop height. However, Comparative Examples 1-2 did not utilize glass sheets meeting the screening criteria of the present invention. Consequently, the chemically strengthened glass products produced after the two-step strengthening process in Comparative Examples 1-2 achieved significantly lower CT_LD and sandpaper drop height than those in Examples 1-3.

[0208] Table 5 shows the strengthening process conditions used in Example 1, Comparative Example 3, and Comparative Example 4 and the properties of the tempered glass obtained.

[0209]

[0210]

[0211] Table 6 shows the strengthening process conditions used in Example 2, Comparative Example 5, and Comparative Example 6 and the properties of the tempered glass obtained.

[0212]

[0213] Table 7 shows the strengthening process conditions used in Example 3, Comparative Example 7, and Comparative Example 8 and the properties of the tempered glass obtained.

[0214]

[0215]

[0216] From the comparison of Tables 5-7, it can be seen that in Examples 1-3, by controlling the properties of the glass obtained after the first ion exchange process, the glass obtained after the first ion exchange process satisfies the following conditions: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first ion exchange process, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500-4000 MPa / mm, which greatly shortens the time of the second ion exchange process (i.e., shortens the time of the second strengthening process). In ensuring that the tempered glass product has a high tensile stress linear density CT_LD, CS 50 While maintaining the high drop resistance and CS, the individual properties of the tempered glass products are also maintained, namely, ensuring that the tempered glass still has high drop resistance and four-point bending strength. However, after the first ion exchange, the difference between the tensile stress linear density (CT_LD1) and the bifurcation threshold in the glasses obtained in Comparative Examples 3, 5, and 7 was less than 1500 MPa / mm. After the second ion exchange, the tensile stress linear density was further reduced, ultimately leading to a significant decrease in the sandpaper drop resistance of the tempered glass products. The sandpaper drop resistance of the tempered glass products obtained in Comparative Examples 3, 5, and 7 was significantly inferior to that of the tempered glass products obtained in Examples 1-3. In contrast, after the first ion exchange, the difference between the tensile stress linear density (CT_LD1) and the bifurcation threshold in the glasses obtained in Comparative Examples 4, 6, and 8 was greater than 4000 MPa / mm. The second ion exchange significantly increased the strengthening time, resulting in a significant decrease in the drop resistance and four-point bending strength of the tempered glass products produced. The monomer properties of the strengthened glass products prepared in Comparative Examples 4, 6, and 8 are significantly inferior to those of the strengthened glass products prepared in Examples 1-3.

[0217] 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 tempered glass having both high stress and high monomer strength, characterized in that: The steps include: S1. Screening out a glass formula suitable for preparing tempered glass with both high stress and high monomer strength, and using the glass formula as the original glass sheet to be tempered. 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 glass with a difference of bifurcation threshold greater than or equal to 3000 MPa / mm, determine the corresponding glass formula, and use the glass with this formula as the original glass sheet to be strengthened; S2, subjecting the glass sheets to be strengthened selected in S1 to two-step ion exchange chemical strengthening, and controlling the process conditions of the two-step ion exchange chemical strengthening, to produce strengthened glass with both high stress and high monomer strength; in S2, When CT_LD max1 When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 0 wt% and less than 20 wt% of sodium nitrate, greater than 80 wt% and less than 100 wt% of potassium nitrate, and 300 to 1,000 ppm of lithium ions, and the salt bath temperature is 420 to 500° C.; When CT_LD max1 When the difference minus the bifurcation threshold is 8,000 to 20,000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes greater than 50 wt% and less than 100 wt% of potassium nitrate and greater than 0 wt% and less than 50 wt% of sodium nitrate, and the salt bath temperature is 420 to 500° C.; When CT_LD max1 When the difference minus the bifurcation threshold is greater than or equal to 3000 MPa / mm and less than 8000 MPa / mm, the salt bath used for the first step of ion exchange on the glass sheet includes 0wt% to 20wt% potassium nitrate and 80wt% to 100wt% sodium nitrate, and the salt bath temperature is 420 to 500°C.

2. The preparation method according to claim 1, characterized in that In S2, according to CT_LD max1 The difference between the bifurcation threshold and the glass is used to control the process conditions of the first step of ion exchange chemical strengthening so that the glass obtained after the first step of ion exchange satisfies the following conditions: the compressive stress depth DOL_1 is greater than or equal to 15.00% of the thickness of the glass obtained after the first step of ion exchange, and the difference between the tensile stress linear density CT_LD1 and the bifurcation threshold is 1500 to 4000 MPa / mm.

3. The preparation method according to claim 1, characterized in that In S2, when CT_LD max1 When the difference minus the bifurcation threshold is greater than 20,000 MPa / mm, the salt bath used for the first step of ion exchange of the glass sheet includes greater than or equal to 5 wt% and less than 20 wt% of sodium nitrate, greater than 80 wt% and less than or equal to 95 wt% of potassium nitrate, and 300 to 1,000 ppm of lithium ions.

4. The preparation method according to claim 1, characterized in that In S2, when CT_LD max1 When the difference minus the bifurcation threshold is 8000-20000 MPa / mm, the salt bath used for the first ion exchange of the glass sheet includes more than 50wt% and less than or equal to 75wt% of potassium nitrate and more than or equal to 25wt% and less than 50wt% of sodium nitrate.

5. The preparation method according to claim 2, characterized in that In S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicon chemically strengthened glass obtained after the second step of 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.

6. The preparation method according to claim 5, characterized in that In S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of 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.

7. The preparation method according to claim 5, characterized in that In S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of 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.

8. The preparation method according to claim 5, characterized in that In S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of 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.

9. The preparation method according to claim 5, characterized in that In S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of 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.

10. The preparation method according to claim 5, characterized in that In S2, the process conditions of the second step of ion exchange chemical strengthening are controlled so that the lithium aluminum silicate chemically strengthened glass obtained after the second step of 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.

11. The preparation method according to claim 10, 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.

12. The preparation method according to claim 10, 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.

13. The preparation method according to any one of claims 5 to 12, characterized in that In S2, the salt bath used for the second step ion exchange of the glass raw sheet includes 95wt% to 100wt% potassium nitrate and 0 to 5wt% sodium nitrate, and the salt bath temperature is 400 to 500°C.

14. A lithium aluminum silicate chemically strengthened glass, prepared by the preparation method according to any one of claims 1 to 13, 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.

15. The tempered glass according to claim 14, wherein The compressive stress depth DOL_0 of the strengthened glass is greater than 16.00% of the thickness of the strengthened glass.

16. The tempered glass according to claim 14, 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.

17. The tempered glass according to claim 14, 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.

18. The tempered glass according to claim 14, 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.

19. The tempered glass according to claim 14, wherein The tempered glass has a sandpaper drop resistance height greater than 1.0 m when converted to a thickness of 0.7 mm.

20. The tempered glass according to claim 19, 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.

21. The tempered glass according to claim 19, 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.

22. The tempered glass according to claim 14, 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.

23. 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 rear surface or / and side surface comprises lithium aluminum silicon chemically strengthened glass prepared by the preparation method according to any one of claims 1 to 13; 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 13; The electronic terminals as consumer products include mobile phones, tablet computers, photovoltaic devices, or other electronic terminals.

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