Borosilicate glass and preparation method thereof

Abstract

The invention relates to the field of glass, and particularly discloses borosilicate glass and a preparation method thereof. According to the borosilicate glass, the oxides SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2 and B2O3 are accurately controlled to meet a specific proportion range, so that the borosilicate glass can give consideration to'loosening 'and'densification' of a glass network, the contradiction between promotion of ion exchange and maintenance of strength is solved, and the chemical strengthening performance of the glass is improved. According to the borosilicate glass, the strength coefficient factor W is greater than or equal to 1.2 MPa.mu m <-1 >, the surface CS is greater than 950 Mpa, the anti-falling height is greater than or equal to 140 cm, the borosilicate glass has high surface stress gradient, crack propagation can be effectively inhibited, the impact resistance and the bending resistance are improved, and the requirements of intelligent electronic products on high strength of the glass due to large screens and light and thin screens can be well met.

Description

Technical Field

[0001] This application relates to the field of glass manufacturing, and more specifically, to a borosilicate glass and a method for preparing the same. Background Technology

[0002] With the continuous advancement of smart electronic product technology, smartphones, tablets, and other mobile touch-screen smart devices are developing towards larger screens and thinner, lighter designs. This trend has significantly improved the appearance and portability of these devices, greatly satisfying consumers' demands for a more comfortable visual experience and convenient carrying, while also driving the further upgrading and diversified applications of the entire smart electronics industry. However, this development also places more stringent requirements on the strength of glass. As a key material for smart device screens, the performance of glass directly affects the device's lifespan and user experience. The strength indicators of glass encompass multiple aspects, such as pressure resistance, flexural strength, tensile strength, and impact resistance, and are influenced by a combination of factors, including the glass's composition, surface and internal condition, operating temperature, and heat treatment conditions.

[0003] In existing technologies, specific methods are often employed to improve the strength of glass. One common method is to adjust its chemical composition during glass manufacturing. For example, increasing the content of certain oxides that enhance the stability of the glass's network structure can strengthen the overall strength of the glass. Ion exchange technology can also be used to exchange ions within the glass with ions from the surrounding environment, forming a compressive stress layer on the glass surface and thus improving its impact resistance. Furthermore, appropriate heat treatment of the glass is also a common method; by controlling the heating and cooling process, the internal structure of the glass can be improved, thereby increasing its strength. Additionally, special additives are added during glass production to alter the physical properties of the glass, making it more robust and durable.

[0004] However, existing methods for improving glass strength have certain drawbacks. While traditional methods of adjusting chemical composition and ion exchange can improve glass strength to some extent, they struggle to simultaneously address both the "loosening" of the glass network to promote ion exchange and the "densification" to maintain strength. In practical applications, either the ion exchange efficiency is low, resulting in poor strengthening; or the glass structure is too dense, hindering ion migration and exchange, preventing the overall performance of the glass from reaching its ideal state and failing to adequately meet the high-strength requirements of large-screen, thin-and-lightweight smart electronic products. Summary of the Invention

[0005] To address the aforementioned problems, this application provides a borosilicate glass and a method for preparing the same.

[0006] The technical solution adopted in this application is as follows:

[0007] In a first aspect, this application provides a borosilicate glass comprising, in oxide form, SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2, and B2O3, wherein the oxides, in parts by mass, simultaneously satisfy the following conditions:

[0008] (1) 5.24≤(SiO2+B2O3-Al2O3) / (Li2O+ZrO2)≤7.86;

[0009] (2) 1.49≤(K2O+Na2O) / Li2O≤3.28;

[0010] (3) 1.78≤(Al2O3-Na2O) / (B2O3+Li2O)≤3.6.

[0011] Furthermore, the elastic modulus of the borosilicate glass is ≥80 GPa, and the stress layer depth D of the borosilicate glass is 12.4 to 14.6.

[0012] Furthermore, the aforementioned stress layer depth D value is calculated based on the following formula:

[0013] D=0.12*SiO2+0.2*Al2O3+0.04*Na2O+0.03*K2O+0.15*MgO+0.10*Li2O+0.06*ZrO2+0.07*B2O3.

[0014] Furthermore, the total mass of the above oxides is 100 wt%, of which:

[0015] SiO261.5wt%-63wt%, Al2O319.4wt%-19.9wt%, Na2O 6.8wt%-7.4wt%, K2O1.3 wt%-1.8wt%, MgO 1.8wt%-3.8wt%, Li2O 4.2wt%-5.2wt%, ZrO21.8wt%-2.6wt%, B2O30.1wt%-2.6wt%.

[0016] Furthermore, the strength factor W of the aforementioned borosilicate glass is calculated according to the following formula, wherein W ≥ 1.2 MPa·μm. -1 :

[0017] W = [CS] 10 -CS 50 ] / 50μm

[0018] In the formula,

[0019] CS 10The compressive stress (MPa) is located 10 μm below the surface.

[0020] CS 50 The compressive stress (MPa) is located 50 μm below the surface.

[0021] Furthermore, the surface CS of the above borosilicate glass is greater than 950 MPa.

[0022] Furthermore, the drop resistance of the aforementioned borosilicate glass is ≥140cm.

[0023] Secondly, this application also provides a method for preparing the above-mentioned borosilicate glass, which includes: mixing and melting the raw materials SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2 and B2O3 in oxide form, and then clarifying, homogenizing, shaping, annealing and chemical strengthening to obtain the glass.

[0024] Furthermore, the above chemical strengthening is a secondary strengthening:

[0025] The first chemical fortification salt bath was 100% NaNO3, and the fortification conditions were: 430-450℃, 60-80min.

[0026] The second chemically enhanced salt bath consisted of a mixed salt of 96-99% KNO3 and 1-4% NaNO3, with enhancement conditions of 410-430℃ for 70-90 minutes.

[0027] Furthermore, the above-mentioned forming process can be any one of the following: float glass, slot casting, casting, or overflow.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. The borosilicate glass provided in this application achieves a balance between the "loosening" and "densification" of the glass network by precisely controlling the proportions of oxides SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2, and B2O3 within a specific range. This resolves the contradiction between promoting ion exchange and maintaining strength, thereby improving the chemical strengthening properties of the glass.

[0030] 2. Furthermore, the borosilicate glass contains specific oxides and meets corresponding ratio conditions to ensure a reasonable glass network structure, allowing for appropriate migration of Li⁺ and Zr. 4The "pinning effect" facilitates the exchange between Li⁺, Na⁺, and K, achieving synergistic optimization of high strain point and low stress relaxation; the elastic modulus ≥80GPa ensures good rigidity of the glass; the stress layer depth D value of 12.4~14.6 ensures the synergistic effect of Li⁺-Na⁺ and Na⁺-K⁺ exchange, avoiding stress unevenness caused by single ion dominance, and taking into account the ion exchange efficiency of Li ions in the glass with Na ions in the molten salt, and Na ions in the glass with K ions in the molten salt.

[0031] 3. The glass provided in this application has a strength coefficient factor W≥1.2MPa·μm⁻¹, surface CS>950Mpa, drop resistance height≥140cm, and a high surface stress gradient, which can effectively inhibit crack propagation, improve impact and bending resistance, and can well meet the high strength requirements of glass for the large screen and thinness of smart electronic products. Detailed Implementation

[0032] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Specific conditions not specified in the examples shall be carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0033] The technical solution of this invention is as follows:

[0034] This application provides a borosilicate glass comprising, in oxide form, SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2, and B2O3, wherein the oxides satisfy the following conditions by mass fraction:

[0035] (1) 5.24≤(SiO2+B2O3-Al2O3) / (Li2O+ZrO2)≤7.86;

[0036] (2) 1.49≤(K2O+Na2O) / Li2O≤3.28;

[0037] (3) 1.78≤(Al2O3-Na2O) / (B2O3+Li2O)≤3.6.

[0038] In this technical solution, the significance of controlling 5.24≤(SiO2+B2O3-Al2O3) / (Li2O+ZrO2)≤7.86 is as follows:

[0039] In the molecule (SiO2 + B2O3 - Al2O3), SiO2 acts as a glass network former, constituting a stable [SiO4] tetrahedral framework. B2O3 partially acts as a network former ([BO3] trigonometric or [BO4] tetrahedron), adjusting the coefficient of thermal expansion and chemical stability. Al2O3 replaces part of [SiO4] in the form of [AlO4], its volume being larger than that of the silicon-oxygen tetrahedron, expanding the network gaps and thus accelerating ion exchange. During strengthening (e.g., K⁺ replacing Li⁺), the larger gaps facilitate the diffusion of alkali metal ions, improving strengthening efficiency. Maintaining structural integrity: the aluminum-oxygen tetrahedron still participates in network construction, preventing a decrease in strength due to excessively large gaps. In the denominator (Li2O + ZrO2), Li2O is a network modifier, providing free Li⁺ for ion exchange, but excessive amounts weaken the network. ZrO2 is a high-field-strength ion, filling network gaps in the form of [ZrO6] octahedrons, enhancing local packing density. Synergistic effect: The controlled ratio of Li⁺ to ZrO₂ ensures: moderate migration of Li⁺ (enhanced performance); Zr 4 The "pinning effect" of ⁺ inhibits network loosening (increases mechanical strength).

[0040] This invention controls the ratio of 1.49 ≤ (K₂O + Na₂O) / Li₂O ≤ 3.28. Within this range, it is beneficial to Li + Na + K + The exchange between components generates sufficient ion exchange depth, improving the chemical strengthening properties of the glass. The innovation of this invention lies in resolving the contradiction between "loosening" (promoting ion exchange) and "densifying" (maintaining strength) of the glass network through precise control of component ratios, providing a new approach for the design of high-performance glasses.

[0041] This invention controls the ratio of Li⁺ to Li⁺ to be 1.49 ≤ (K₂O + Na₂O) / Li₂O ≤ 3.28. The dominant role of Li⁺ is that Li₂O provides Li⁺ ions in the glass. Due to its small ionic radius (≈0.76 Å), it is easily replaced by larger Na⁺ (≈1.02 Å) or K⁺ (≈1.38 Å) ions during chemical strengthening, thus forming a compressive stress layer on the surface. Synergistic effects: Na₂O and K₂O act as melt fluxes, reducing glass viscosity while simultaneously providing Na⁺ and K⁺ for ion exchange. K⁺ has a larger radius, enhancing the compressive stress depth, while Na⁺ diffuses rapidly, facilitating the rapid formation of the initial stress layer. Furthermore, the lower limit (≥1.49) ensures sufficient total Na₂O and K₂O, preventing excessive Li₂O from causing glass structural instability (such as crystallization), while providing ample Na⁺ / K⁺ for Li⁺ exchange. Upper limit (≤3.28): This prevents excessive Na₂O and K₂O from inhibiting Li⁺ migration, leading to insufficient exchange depth or uneven stress layer. Excessive alkali metal content may also reduce the glass's weather resistance.

[0042] This invention controls the ratio to 1.78 ≤ (Al2O3-Na2O) / (B2O3+Li2O) ≤ 3.6. This ratio range achieves synergistic optimization of high strain point and low stress relaxation by precisely controlling the competitive relationship between the glass network forging body (Al2O3), the modifier (Na2O), and the flux / exchange components (B2O3 / Li2O). It is suitable for demanding display cover plates or ultra-thin glass products. Furthermore, the lower limit of the range ≥ 1.78 ensures sufficient relative Al2O3 content, maintaining a high strain point and network stability, and suppressing stress relaxation during chemical strengthening (e.g., potassium salt bath at 400–450℃). The upper limit of the range ≤ 3.6 avoids excessively high melting temperature or insufficient ion exchange rate due to insufficient B2O3 and Li2O, which would affect production efficiency.

[0043] Furthermore, the elastic modulus of the borosilicate glass is ≥80 GPa, and the stress layer depth D of the borosilicate glass is 12.4 to 14.6.

[0044] D=0.12*SiO2+0.2*Al2O3+0.04*Na2O+0.03*K2O+0.15*MgO+0.10*Li2O+0.06*ZrO2+0.07*B2O3

[0045] This configuration balances the efficiency of ion exchange between Li ions in the glass and Na ions in the molten salt, as well as the efficiency of ion exchange between Na ions in the glass and K ions in the molten salt. D = 12.4–14.6: This value quantifies the balance of the glass composition through weighted summation. The range corresponds to the following characteristics:

[0046] Ion exchange efficiency: Ensure the synergistic effect of Li⁺-Na⁺ and Na⁺-K⁺ exchanges, avoiding stress unevenness caused by single ion dominance. Stress layer depth and intensity: A D value that is too high (e.g., >14.6) may lead to excessive Li₂O, causing excessive stress or crystallization; a value that is too low (<12.4) will result in insufficient exchange. Simultaneously satisfying dual ion exchange pathways:

[0047] (1) Li⁺ ⇌ Na⁺ (low temperature): Li₂O content (weight 0.10) ensures rapid diffusion and forms deep compressive stress.

[0048] (2) Na⁺ ⇌ K⁺ (high temperature): A small amount of Na₂O (0.04) allows for secondary exchange, which enhances the surface compressive stress.

[0049] Synergistic effect: Al2O3 and B2O3 may form a mixed [AlO4 / BO4] structure, providing a channel for the migration of alkali metal ions.

[0050] Furthermore, the total mass of the above oxides is 100 wt%, of which:

[0051] The mass percentage of SiO2 is 61.5wt%-63wt%; SiO2 is a component that forms the network of the glass. If the SiO2 content is too low, vitrification is difficult, and the coefficient of thermal expansion tends to be too high, reducing thermal shock resistance. Additionally, resistance to hydrofluoric acid may also decrease. Preferably, the mass percentage of SiO2 is [missing information]. 62wt%-63wt%.

[0052] The mass percentage of Al2O3 is 19.4 wt%-19.9 wt%. Al2O3 is a component that improves ion exchange performance, and also improves strain point, Young's modulus, fracture toughness, and Vickers hardness. Preferably, the mass percentage of Al2O3 is 19.6 wt%-19.8 wt%.

[0053] The mass percentage of Na₂O is 6.8 wt%-7.4 wt%; Na₂O is an ion-exchange component and also a component that reduces viscosity at high temperatures and improves meltability and formability. Preferably, the mass percentage of Na₂O is 7.0 wt%-7.3 wt%.

[0054] The mass percentage of K2O is 1.3 wt%-1.8 wt%; K2O is a component that reduces viscosity at high temperatures and improves meltability and formability. Furthermore, it is a component that increases stress depth. Preferably, the mass percentage of K2O is 1.5 wt%-1.7 wt%.

[0055] The mass percentage of MgO is 1.8 wt%-3.8 wt%. MgO is a component that reduces high-temperature viscosity, improves meltability and formability, and increases strain point, Vickers hardness, Young's modulus, and fracture toughness. Among alkaline earth metal oxides, it is the component with the greatest effect on improving ion exchange performance. Preferably, the mass percentage of MgO is 2.4 wt%-3.2 wt%.

[0056] The mass percentage of Li₂O is 4.2 wt%-5.2 wt%. Li₂O is an ion-exchange component, particularly effective in exchanging Li ions in the glass with Na ions in the molten salt, making it efficient for achieving deep stress depth. Additionally, Li₂O reduces high-temperature viscosity, improves melt flowability and formability, and increases the elastic modulus. Preferably, the mass percentage of Li₂O is 4.5 wt%-5.0 wt%.

[0057] The mass percentage of ZrO2 is: 1.8wt%-2.6wt%; ZrO2 is a network intermediate oxide that can participate in the glass network structure, playing a role in reinforcing the network structure. Simultaneously, the addition of ZrO2 can stabilize the glass network structure, reduce the glass's deformation and cracking tendency under heat or stress, and improve the glass's heat resistance and mechanical stability. Preferably, the mass percentage of ZrO2 is 2.0wt%-2.4wt%.

[0058] The mass percentage of B2O3 is 0.1wt%-2.6wt%. B2O3 is a component that reduces viscosity and density at high temperatures, stabilizes glass, makes it difficult for crystals to precipitate, and lowers the liquidus temperature. Furthermore, it increases the binding force of cations on oxygen electrons, thus reducing the basicity of the glass. If the B2O3 content is too low, the stress depth in the ion exchange between Li ions in the glass and Na ions in the molten salt becomes too deep. Preferably, the mass percentage of B2O3 is 0.5wt%-2.1wt%.

[0059] Furthermore, the strength factor W of the aforementioned borosilicate glass is calculated according to the following formula, wherein W ≥ 1.2 MPa·μm. -1 :

[0060] W = [CS] 10 -CS 50 ] / 50μm

[0061] In the formula,

[0062] CS 10 The compressive stress (MPa) is located 10 μm below the surface.

[0063] CS 50 The compressive stress (MPa) is located 50 μm below the surface.

[0064] 50μm: Depth difference between stress measurement points.

[0065] The strength factor W reflects the gradient of compressive stress (CS) on the glass surface with depth and is an important parameter for measuring the mechanical strength of glass. W ≥ 1.2 MPa·μm⁻¹: indicates that the glass has a high surface stress gradient, which can effectively inhibit crack propagation and improve impact and bending resistance. The preferred range is 1.2~1.8 MPa·μm⁻¹: balancing strength and brittleness, avoiding excessively high W that could lead to sensitivity to surface microcracks.

[0066] Furthermore, the surface CS of the aforementioned borosilicate glass is greater than 950 MPa. The drop resistance of the aforementioned borosilicate glass is ≥140 cm.

[0067] Secondly, this application also provides a method for preparing the above-mentioned borosilicate glass, which includes: mixing and melting the raw materials SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2 and B2O3 in oxide form, and then clarifying, homogenizing, shaping, annealing and chemical strengthening to obtain the glass.

[0068] Furthermore, the above chemical strengthening is a secondary strengthening:

[0069] The first chemical fortification salt bath was 100% NaNO3, and the fortification conditions were: 430-450℃, 60-80 min; preferably...

[0070] The second chemically enhanced salt bath consisted of a mixed salt of 96-99% KNO3 and 1-4% NaNO3, with enhancement conditions of 410-430℃ for 70-90 minutes.

[0071] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0072] Example

[0073] This set of embodiments provides a borosilicate glass, the preparation method of which includes:

[0074] (1) Prepare materials according to the mass percentage of each oxide in Table 1;

[0075] (2) After mixing the raw materials, the mixture is melted, clarified, and shaped to obtain a glass matrix;

[0076] (3) Anneal and chemically strengthen the glass matrix to obtain borosilicate glass.

[0077] The technical parameters for chemical strengthening are as follows:

[0078] The first chemical fortification salt bath was 100% NaNO3, and the fortification conditions were: 440℃, 70min;

[0079] The second chemical fortification salt bath was a mixed salt of 98% KNO3 and 2% NaNO3, and the fortification conditions were: 420℃ for 80 min.

[0080] Table 1.

[0081] serial number <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Na2O]]> <![CDATA[K2O]]> MgO <![CDATA[ZrO2]]> <![CDATA[B2O3]]> <![CDATA[Li2O]]> Example 1 61.5 19.4 7.2 1.5 2.4 2.6 0.2 5.2 Example 2 63.0 19.9 6.8 1.3 1.8 2.5 0.5 4.2 Example 3 61.9 19.5 7.4 1.8 3.3 1.8 0.1 4.2 Example 4 61.5 19.6 6.8 1.3 1.9 1.9 2.6 4.4 Example 5 62.5 19.8 7.0 1.6 2.2 2.0 0.4 4.5 Example 6 62.1 19.5 7.0 1.4 2.8 1.8 1.0 4.4 Comparative Example 1 64.5 14.5 8.2 4.8 1.2 1.0 2.8 3.0 Comparative Example 2 60.4 16.8 7.8 3.1 3.9 1.2 3.0 3.8 Comparative Example 3 59.8 13.8 8.5 5.6 4.0 1.0 2.7 4.6

[0082] Based on Table 1, the proportional relationships and D values ​​among the various oxides in the borosilicate glass were further calculated. The D value was calculated as follows:

[0083] D=0.12*SiO2+0.2*Al2O3+0.04*Na2O+0.03*K2O+0.15*MgO+0.10*Li2O+0.06*ZrO2+0.07*B2O3

[0084] The results are shown in Table 2:

[0085] Table 2.

[0086] serial number <![CDATA[(SiO2+B2O3-Al2O3) / (Li2O+ZrO2)]]> <![CDATA[(K2O+Na2O) / Li2O]]> <![CDATA[(Al2O3-Na2O) / (B2O3+Li2O)]]> D value Example 1 5.4 1.7 2.3 12.6 Example 2 6.5 1.9 2.8 12.7 Example 3 7.1 2.2 2.8 12.7 Example 4 7.1 1.8 1.8 12.6 Example 5 6.6 1.9 2.6 12.7 Example 6 7.0 1.9 2.3 12.7 Comparative Example 1 13.2 4.3 1.1 11.8 Comparative Example 2 9.3 2.9 1.3 12.3 Comparative Example 3 8.7 3.1 0.7 11.8

[0087] Performance tests were conducted on the glasses provided in Examples 1-6 and Comparative Examples 1-3.

[0088] 1. Testing method:

[0089] (1) The stress and stress layer depth of the glass were tested using an Origen SLP-2000 stress tester. Ten test samples were used. A sandpaper drop test was conducted using a XH-YF1000 drop tester. The test conditions were: 180-grit sandpaper, a total weight of 186 grams for the glass sample and fixture, a base height of 50 cm, a drop height of 5 cm each time, repeated once at each height until the glass broke. Twenty test samples were used.

[0090] (2) The test method for elastic modulus refers to JC / T678-1997. The test device mainly consists of an audio generator, an audio amplifier, a power amplifier, a frequency detector, an oscilloscope, and a transducer. The audio generator is used to generate a sine wave, which is converted into mechanical vibration by the resonant transducer to make the glass sample vibrate. The resonance generated by the material is then converted into an electrical signal by the detection transducer. After being amplified by the power amplifier, the resonant frequency is measured by the frequency detector. Then, the elastic modulus or shear modulus of the material can be obtained by certain calculations.

[0091] The cross-section of the specimen for determining the elastic modulus should be rectangular or circular. A rectangular specimen should be 120 mm x 25 mm x 3 mm. The specimen should be suspended by a metal wire, with the suspension point within 0.224L of the specimen length and on the center line of the specimen. An audio generator should produce vibrations, which, through a transducer, excite the specimen to induce bending vibrations.

[0092] With the sample unexcited, adjust the oscilloscope to produce a horizontal baseline. Adjust the gain of the probe circuit to amplify the detected sample vibration, maximizing the signal and displaying it on the oscilloscope for accurate frequency measurement. Slowly adjust the frequency of the audio generator until the maximum sine wave generated by the sample is displayed on the oscilloscope. Locate the fundamental bending frequency at the steady-state resonance of the sample. To determine the fundamental frequency, suspend the probe at the sample node. At this point, the resonance signal will drop to zero, indicating that the previous resonance frequency was the fundamental bending frequency.

[0093] Calculation of elastic modulus

[0094] Calculate using the following formula:

[0095] E = 94.65 (L 3 / bt 3 T1wf 2 x10 -12

[0096] Where: E is the elastic modulus, GPa; L is the sample length, cm; b is the sample width, cm; t is the sample thickness, cm; w is the sample weight, g; f is the resonant frequency of the sample, Hz; T1 is the correction factor.

[0097] 2. Test Results:

[0098] The specific test results are shown in Table 3.

[0099] Table 3.

[0100] serial number <![CDATA[W=[CS 10 -CS 50 ] / 50μm]]> CS(MPa) Fall height (cm) Elastic modulus (GMP) Example 1 1.58 1063 145 84 Example 2 1.62 1086 155 83 Example 3 1.59 1120 150 86 Example 4 1.78 1087 145 82 Example 5 1.72 1042 140 84 Example 6 1.65 1100 145 84 Comparative Example 1 2.08 890 80 72 Comparative Example 2 1.11 888 100 70 Comparative Example 3 1.90 820 90 76

[0101] As can be seen from Table 3:

[0102] The strength coefficient W of the glass provided in Examples 1-6 of this application is between 1.5 and 1.8 MPa·μm. -1 Within the specified range, the surface stress gradient (CS) is greater than 1000 MPa, and the drop height is greater than 140 cm. This indicates that by precisely controlling the component ratio, the oxides can meet the following conditions by mass fraction: (1) 5.24≤(SiO2+B2O3-Al2O3) / (Li2O+ZrO2)≤7.86; (2) 1.49≤(K2O+Na2O) / Li2O≤3.28; (3) 1.78≤(Al2O3-Na2O) / (B2O3+Li2O)≤3.6. The obtained glass has a high surface stress gradient and mechanical strength.

[0103] By comparing Examples 1-6 with Comparative Examples 1-3, it can be seen that when the above conditions are not met in the component ratio control, that is, (SiO2+B2O3-Al2O3) / (Li2O+ZrO2) is greater than 7.86, (K2O+Na2O) / Li2O is greater than 3.28, and (Al2O3-Na2O) / (B2O3+Li2O) is less than 1.78, the surface stress of the glass is significantly reduced to below 900 MPa, and the decay height is also reduced to 80-100 cm, which is insufficient to meet the high strength requirements of glass for the large screen and thinness of smart electronic products.

[0104] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A borosilicate glass, characterized in that, The borosilicate glass comprises, in oxide form, SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2, and B2O3, wherein the oxides, by mass fraction, satisfy the following conditions: (1) 5.24≤(SiO2+B2O3-Al2O3) / (Li2O+ZrO2)≤7.86; (2) 1.49≤(K2O+Na2O) / Li2O≤3.28; (3) 1.78≤(Al2O3-Na2O) / (B2O3+Li2O)≤3.

6.

2. The borosilicate glass according to claim 1, characterized in that, The borosilicate glass has an elastic modulus ≥80 GPa and a stress layer depth D of 12.4 to 14.

6.

3. The borosilicate glass according to claim 2, characterized in that, The stress layer depth D value is calculated based on the following formula: D=0.12*SiO2+0.2*Al2O3+0.04*Na2O+0.03*K2O+0.15*MgO+0.10*Li2O+0.06*ZrO2+0.07*B2O3.

4. The borosilicate glass according to claim 1, characterized in that, The total mass of the oxide is 100 wt%, of which: SiO261.5wt%-63wt%, Al2O319.4wt%-19.9wt%, Na2O 6.8wt%-7.4wt%, K2O 1.3wt%-1.8wt%, MgO 1.8wt%-3.8wt%, Li2O 4.2wt%-5.2wt%, ZrO21.8wt%-2.6wt%, B2O30.1wt%-2.6wt%.

5. The borosilicate glass according to claim 4, characterized in that, The strength factor W of the borosilicate glass is calculated according to the following formula, where W ≥ 1.2 MPa·μm. -1 : W=[CS 10 -CS 50 ] / 50μm In the formula, CS 10 The compressive stress (MPa) is located 10 μm below the surface. CS 50 The compressive stress (MPa) is located 50 μm below the surface.

6. The borosilicate glass according to claim 4, characterized in that, The surface CS of the borosilicate glass is greater than 950 MPa.

7. The borosilicate glass according to claim 4, characterized in that, The borosilicate glass has a drop resistance height of ≥140cm.

8. A method for preparing borosilicate glass according to any one of claims 1-7, characterized in that, It includes: mixing and melting the raw materials SiO2, Al2O3, Na2O, K2O, MgO, Li2O, ZrO2, and B2O3 in oxide form, followed by clarification, homogenization, shaping, annealing, and chemical strengthening.

9. The method for preparing borosilicate glass according to claim 8, characterized in that, The chemical strengthening is a secondary strengthening: The first chemical fortification salt bath was 100% NaNO3, and the fortification conditions were: 430-450℃, 60-80min. The second chemically enhanced salt bath consisted of a mixed salt of 96-99% KNO3 and 1-4% NaNO3, with enhancement conditions of 410-430℃ for 70-90 minutes.

10. The method for preparing borosilicate glass according to claim 8, characterized in that, The forming process can be any one of the following: float glass, slot casting, casting, or overflow.