Protective glass, super-strong impact-resistant protective glass and preparation method and application thereof

Abstract

The invention relates to the technical field of glass, in particular to protective glass, super-strong impact-resistant protective glass as well as a preparation method and application of the super-strong impact-resistant protective glass. The protective glass comprises the following raw materials in percentage by mass: 50%-65% of SiO2, 20%-30% of Al2O3, 0%-10% of B2O3, 2%-6% of Li2O, 1%-6% of Na2O, 0%-4% of K2O, 0%-1% of MgO, 0%-2% of CaO, 0%-2% of SrO, 0%-2% of ZnO, 0%-8% of P2O5 and 0%-1% of a clarifying agent, the ratio of Li2O + Na2O + K2O is 5%-12%, and the ratio of MgO + CaO + SrO + ZnO is 0%-5%. According to the invention, by controlling the mass percentage range of the raw materials, the obtained protective glass is ensured to have good impact resistance after being chemically strengthened.

Description

Technical Field

[0001] The present invention relates to the technical field of glass, and particularly to a protective glass, a super-strong impact-resistant protective glass, and a preparation method and application thereof. Background Art

[0002] In recent years, with the development of modern technology, the replacement rate of portable electronic devices such as smart phones, tablet PCs, and smart watches has become higher and higher. In the information age, there are higher requirements for electronic display devices, hoping that they are thinner, easier to carry, and have higher impact resistance.

[0003] When a heavy object impacts and falls on the surface of an electronic product, it may cause scratches on the glass surface, resulting in sharp indentations. These indentations become the damaged positions on the glass surface, and cracks may occur and propagate from these positions, leading to surface breakage accidents. In these devices, the protective glass plays a role in protecting the display screen and may incorporate touch functionality. When the protective glass is damaged, the touch use of the electronic device will also be affected, which has become an urgent problem to be solved.

[0004] Therefore, for the protective glass of portable electronic products, it is required to be scratch-resistant and have high impact resistance. In addition, due to the current demand for aesthetic effects, it is also required to be as thin as possible. Summary of the Invention

[0005] The purpose of the present invention is to provide a protective glass to solve the problem of insufficient impact resistance performance of the protective glass after strengthening when applied in electronic products in the prior art.

[0006] The present invention also provides a preparation method of a protective glass to solve the problem of insufficient impact resistance performance of the protective glass after strengthening when applied in electronic products in the prior art.

[0007] The present invention also provides a super-strong impact-resistant protective glass to solve the problem of insufficient impact resistance performance of the impact-resistant protective glass prepared by strengthening the protective glass in the prior art when applied in electronic products.

[0008] The present invention also provides a preparation method of a super-strong impact-resistant protective glass to solve the problem of insufficient impact resistance performance of the impact-resistant protective glass prepared by strengthening the protective glass in the prior art when applied in electronic products.

[0009] The present invention also provides an application of the super-strong impact-resistant protective glass in the display device and the back cover material of a mobile device to solve the problem of insufficient impact resistance of the impact-resistant protective glass when applied in the back cover material in the prior art.

[0010] To solve the above problems, the present invention provides a protective glass, and the technical solution adopted is: a protective glass, by mass percentage, its raw materials include: 50% - 65% SiO 2 、20% - 30% Al 2 O 3 、0% - 10% B 2 O 3 、2% - 6% Li 2 O, 1% - 6% Na 2 O, 0% - 4% K 2 O, 0% - 1% MgO, 0% - 2% CaO, 0% - 2% SrO, 0% - 2% ZnO, 0% - 8% P 2 O 5 、0% - 1% clarifying agent, wherein, Li 2 O + Na 2 O + K 2 O is 5% - 12%, and MgO + CaO + SrO + ZnO is 0% - 5%.

[0011] The beneficial effects of the present invention are: SiO 2 is an essential component for forming the glass network structure of the precursor glass-ceramics. The content of SiO 2 is designed to be 50% - 65%, which is beneficial to obtaining glass with strong chemical stability and forming ability; the content of Al 2 O 3 is designed to be 20% - 30%, which makes the glass have a certain viscosity and a dense structure, improves the ion exchange rate of the glass, and increases the maximum surface compressive stress and the stress layer compression depth obtained; the content of B 2 O 3 is designed to be 0% - 10% to reduce the viscosity of the glass and can also be used as a flux to help reduce the softening point of the obtained glass; the content of Li 2 O is designed to be 2% - 6% to reduce the softening point of the base glass composition and participate in the ion exchange process; the content of Na 2 O is designed to be 1% - 6% and the content of K 2 O is designed to be 0% - 4% to improve the forming of the base glass composition and regulate the ion exchange process; alkaline earth metal oxides (MgO, CaO, SrO, ZnO) are components that reduce the liquid phase temperature and make it difficult to generate crystalline foreign substances in the glass, and are also components that improve fusibility and formability. Therefore, in the present invention, the content of MgO is designed to be 0% - 1%, the content of CaO is designed to be 0% - 2%, the content of SrO is designed to be 0% - 2%, and the content of ZnO is designed to be 0% - 2%; the content of P 2 O 5 is designed to be 0% - 8% to make the glass structure loose, which is beneficial to increasing the ion exchange depth of the glass, and with the mass percentage content of Na being 1% - 6%2 O and K with a mass percentage content of 0% to 4% 2 Combined with O, it can reduce the softening point of the glass, enabling ion exchange to reach a deeper depth on the glass surface, thereby obtaining the required surface compressive stress and stress layer compression depth; the clarifying agent content is designed to be 0% to 1% to promote the elimination or dissolution and absorption of bubbles in the glass melt.

[0012] Among them, Li 2 O + Na 2 O + K 2 O is 5% to 12%, which is used to balance the high viscosity brought by A1 2 O 3 Adjust the glass network structure, improve the formability of the base glass composition, thereby affecting the glass density, and promote the ion exchange process for chemical strengthening, improving the comprehensive strength performance of the strengthened glass; MgO + CaO + SrO + ZnO is 0% to 5%, which is used to form new compounds with the silicate in the glass, thereby reducing the melting point of the glass, increasing the glass expansion coefficient, affecting the short-range and medium-range structures of the glass, and further improving the chemical stability of the glass, as well as its mechanical properties such as elastic modulus and fracture toughness.

[0013] By controlling the mass percentage ranges of the above-mentioned raw materials in this application, it is ensured that the obtained protective glass has a high ion exchange layer depth, a long salt bath service life, good impact resistance, good thermal stability and high strength after chemical strengthening, is not prone to warping, and has the mechanical properties to be processed into thin glass products, so as to meet the requirements of the glass cover plate for light and strong mechanical properties, and can meet the requirements of customers for the portability and mechanical properties of electronic products after reprocessing.

[0014] In order to further improve the comprehensive strength performance of the glass after chemical strengthening, preferably, in the raw materials: (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + ZnO) / Al 2 O 3 ≤1.

[0015] In order to further improve the ion exchange layer depth and impact resistance of the protective glass after chemical strengthening, preferably, by mass percentage, its raw materials include: 53% to 63% SiO 2 , 22% to 28% Al 2 O 3 , 0% to 7% B 2 O 3 , 2% to 5% Li 2 O, 2% to 5% Na 2 O, 0% to 2.5% K 2O, 0% - 1% MgO, 0% - 2% CaO, 0% - 1.5% SrO, 0% - 1.5% ZnO, 0% - 6.5% P 2 O 5 , 0.1% - 0.2% clarifying agent, wherein, Li 2 O + Na 2 O + K 2 O is 5% - 11%, MgO + CaO + SrO + ZnO is 0.9% - 4%, (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + ZnO) / Al 2 O 3 is 0.3 - 0.6.

[0016] In order to further improve the impact resistance of the dropped ball that the protective glass can withstand after chemical strengthening and the height of the whole machine drop and breakage, preferably, by mass percentage, its raw materials include: 56% - 63% SiO 2 , 25% - 27.5% Al 2 O 3 , 3% - 7% B 2 O 3 , 3% - 4.5% Li 2 O, 2.2% - 3.7% Na 2 O, 0% - 2.1% K 2 O, 0% - 0.65% MgO, 0% - 1.3% CaO, 0.1% - 0.6% SrO, 0% - 2.2% P 2 O 5 , 0.12% - 0.15% clarifying agent, wherein, Li 2 O + Na 2 O + K 2 O is 5.3% - 9.2%, MgO + CaO + SrO + ZnO is 0.9% - 2.1%, (Li 2 O + Na 2 O + K 2 O + MgO + CaO + SrO + ZnO) / Al 2 O 3 is 0.3 - 0.5.

[0017] The present invention also provides a preparation method of a protective glass, and the technical solution adopted is: A preparation method of a protective glass, mixing, melting, forming and annealing the raw materials in sequence to obtain the protective glass.

[0018] The beneficial effects of the present invention are as follows: the preparation method is simple and convenient, and the protective glass can be obtained by mixing, melting, molding and annealing various raw materials, and the operation is simple and suitable for large-scale industrial applications.

[0019] In order to reduce or eliminate the stress inside the prepared protective glass and prevent the protective glass from cracking or breaking during subsequent processing or use, preferably, the annealing temperature is 600-800° C. and the time is 8-48 hours.

[0020] The present invention also proposes a super impact-resistant protective glass, and the technical solution adopted is: A super impact-resistant protective glass, which is formed by chemically strengthening the protective glass or the protective glass prepared by the protective glass preparation method.

[0021] The beneficial effect of the present invention is that after chemical strengthening treatment, the protective glass is obtained into super impact-resistant protective glass, and the glass density is greater than 2.38g / cm 3 The softening point is less than 900℃, ranging from 857 to 896℃, with a surface compressive stress of at least 896MPa, and a stress layer compression depth of at least 101.5μm extending from the glass surface to the inside; the thermal expansion coefficient is less than 66.1×10 -7 / ℃, Young's modulus is higher than 74GPa, the drop ball impact force it can withstand is greater than 0.25J, and the whole machine can fall and break to a height of 1900mm. The resulting super-strong impact-resistant protective glass has high strength and good whole machine drop performance, high drop ball impact force, high strength and impact resistance.

[0022] The present invention also proposes a method for preparing super impact-resistant protective glass, and the technical solution adopted is: A method for preparing super-strong impact-resistant protective glass, wherein the protective glass or the protective glass prepared by the protective glass preparation method is placed in an alkali metal molten salt for a first step chemical strengthening treatment and a second step chemical strengthening treatment to obtain the super-strong impact-resistant protective glass.

[0023] The beneficial effects of the present invention are as follows: the above-mentioned preparation method can obtain impact-resistant protective glass with a deeper ion exchange layer through two chemical strengthening processes; the super-strong impact-resistant protective glass is a chemically strengthened protective glass with a higher ion exchange layer depth, a long salt bath service life, and good impact resistance; after reprocessing, it can meet customers' requirements for the portability and mechanical properties of electronic products, solves the requirements of the glass cover plate for light and strong mechanical properties, and can be used as a shell component of consumer electronic products such as mobile phones and tablets; the preparation method is safe, easy to operate and low in cost.

[0024] In order to further improve the uniform ion exchange inside the glass, preferably, the temperature of the first-step chemical strengthening treatment is 400-480 °C, and the time is 0.5-2 h; the temperature of the second-step chemical strengthening treatment is 400-450 °C, and the time is 0.5-1.5 h; the alkali metal molten salt is sodium nitrate molten salt or potassium nitrate molten salt or a mixed molten salt of sodium nitrate and potassium nitrate, and the mixed molten salt of sodium nitrate and potassium nitrate includes 20-100 wt% of potassium nitrate and 0-80 wt% of sodium nitrate.

[0025] The present invention also proposes an application of a super-strong impact-resistant protective glass or a super-strong impact-resistant protective glass prepared by a preparation method of a super-strong impact-resistant protective glass in a back cover material of a display device and a mobile device.

[0026] The beneficial effects of the present invention are as follows: Since the super-strong impact-resistant protective glass is a chemically strengthened protective glass with a relatively high ion exchange layer depth, a long service life of the salt bath, and good impact resistance, it has good overall machine drop performance, high ball drop impact force, high strength and impact resistance. When it is applied in the back cover material of a display device and a mobile device, it can meet the requirements of customers for the portability of electronic products and the mechanical properties. Specific embodiments

[0027] In the prior art, the impact resistance strength performance of the protective glass after strengthening is insufficient when applied in electronic products. The present invention proposes a protective glass, and by mass percentage, its raw materials include: 50%-65% SiO 2 、20%-30% Al 2 O 3 、0%-10% B 2 O 3 、2%-6% Li 2 O、1%-6% Na 2 O、0%-4% K 2 O、0%-1% MgO、0%-2% CaO、0%-2% SrO、0%-2% ZnO、0%-8% P 2 O 5 、0%-1% clarifying agent, wherein, Li 2 O + Na 2 O + K 2 O is 5%-12%, and MgO + CaO + SrO + ZnO is 0%-5%.

[0028] The technical concept of the present invention is: in the protective glass, SiO 2 is an essential component for forming the glass network structure of the precursor glass-ceramics. In the present invention, if the content of SiO 2 is too high, it will cause an excessive increase in viscosity and a decrease in meltability. Therefore, in the present invention, SiO 2With a content of 50% to 65%, glass with strong chemical stability and formability can be obtained.

[0029] Al 2 O 3 is an essential component for providing a stabilizing effect to the network, forming the network structure, and is also an essential component for forming the crystalline phase. Its relatively large volume structure is beneficial to the ion exchange process between the glass and the molten salt, helping to improve the mechanical properties of the glass and enhance chemical durability. In the present invention, if the content of Al 2 O 3 is too high, the viscosity increases, and at the same time its meltability decreases. Therefore, in the present invention, the content of Al 2 O 3 is 20% to 30%, enabling the glass to have a certain viscosity and a dense structure, increasing the ion exchange rate of the glass, and increasing the maximum surface compressive stress and the stress layer compression depth obtained.

[0030] B 2 O 3 belongs to network-forming oxides and can form a network alone. In the present invention, the content of B 2 O 3 is 0% to 10%, which is used to reduce the viscosity of the glass and can also act as a flux to help reduce the softening point of the obtained glass.

[0031] Li 2 O can reduce the softening point of the base glass composition and participate in the ion exchange process. If the content of Li 2 O is less than 2%, the ion exchange enhancement effect is not good, but if the content of Li 2 O is too high, the viscosity is too low and the composition becomes fluid-like, so that the base glass cannot be formed. Therefore, the content of Li 2 O in the glass of the present invention is 2% to 6%.

[0032] Na 2 O and K 2 O, as the alkali metal oxides in the base glass other than Li 2 O, are mainly used to improve the formability of the base glass composition and adjust its thermal expansion coefficient. If the content of Na 2 O and K 2 O is too high, it may cause the thermal expansion coefficient to be too high. Therefore, the content of the alkali metal oxide R 2 O (Li 2 O + Na 2 O + K 2 O) is designed to be 5% to 12% to balance the high viscosity brought by A1 2 O 3 and improve the formability of the base glass composition and achieve the ion exchange process.

[0033] The content of the alkaline earth metal oxide R'O (MgO + CaO + SrO + ZnO) is designed to be 0% - 5%, which is used to form new compounds with silicates in the glass, thereby reducing the melting point of the glass and improving the chemical stability of the glass.

[0034] In the present invention, the content of P 2 O 5 is 0% - 8%, which makes the glass structure loose, conducive to increasing the ion exchange depth of the glass, and combines with Na 2 O with a mass percentage content of 1% - 6% and K 2 O with a mass percentage content of 0% - 4%, which can reduce the softening point of the glass, enabling the ion exchange to reach a deeper depth on the glass surface, thereby obtaining the required surface compressive stress and stress layer compression depth.

[0035] The clarifying agent is added to the basic glass components, which can promote the elimination or dissolution and absorption of bubbles in the glass melt. The mass percentage of the designed clarifying agent is 0% - 1%, which can promote the elimination or dissolution and absorption of bubbles in the glass melt. Therefore, the glass finally obtained after melting, high-temperature heat treatment, and ion exchange in molten salt can be formed into a double-strength cover glass with a low softening point, having good scratch resistance and impact resistance.

[0036] By controlling the mass percentage ranges of the above-mentioned raw materials in this application, it is ensured that the obtained protective glass can achieve a chemically strengthened protective glass with a high ion exchange layer depth, a long service life of the salt bath, and good impact resistance after chemical strengthening. After reprocessing, it can meet the requirements of customers for the portability of electronic products and the mechanical properties, and solve the requirements of the glass cover plate for light and strong mechanical properties. The surface compressive stress (CS) of the super-strong impact-resistant protective glass prepared in this application can reach up to 1013 Mpa at most; the stress layer depth (DOL) can reach up to 121.7 μm at most; the thermal expansion coefficient in the temperature range of 30 - 380 °C is at least 57.9×10 -7 / °C; the density can reach up to 2.53 g / cm 3 ; the softening point is between 857 - 896 °C, all less than 900 °C; the stress intensity factor (KIC) is 1.1 MPa·m 1 / 2 ; the Young's modulus can reach up to 81 Gpa at most; the falling ball can reach up to 0.4 J at most; the simulated whole machine drop can reach up to 1900 mm at most.

[0037] Specifically, the preparation method of the protective glass includes the following steps: (1) Calculate and weigh the raw materials corresponding to each component according to the component ratios, and perform a mixing process on the raw materials of each component to obtain a mixed material; (2) Put the mixed materials into a platinum crucible for melting. The melting method can be the way of a fully electric melting furnace or the way of a flame combined with an electro-assisted melting furnace. Carry out melting at 1500 - 1680 °C for 8 h to obtain glass liquid; (3) Cast the glass liquid into a preheated stainless steel mold to form a glass plate with a specified shape; Finally, after the glass is formed and demolded, put it into an annealing furnace for annealing. The annealing temperature is 600 - 800 °C and the time is 8 - 48 h to prepare the protective glass, and then cut the obtained protective glass into sheet glass with a thickness of 0.7 mm; Specifically, the preparation method of the super-strong impact-resistant protective glass includes the following steps: Place the sheet glass prepared above in an alkali metal molten salt for the first-step chemical strengthening treatment and the second-step chemical strengthening treatment to obtain the super-strong impact-resistant protective glass. Among them, the conditions of the first-step chemical strengthening treatment and the second-step chemical strengthening treatment are: Conditions of the first-step chemical strengthening treatment: The temperature is 400 - 480 °C, the time is 0.5 - 2 h, and the alkali metal molten salt includes 20 - 100 wt% potassium nitrate and 0 - 80 wt% sodium nitrate; Conditions of the second-step chemical strengthening treatment: The temperature is 400 - 450 °C, the time is 0.5 - 1.5 h, and the alkali metal molten salt includes 20 - 100 wt% potassium nitrate and 0 - 80 wt% sodium nitrate.

[0038] Preferably, the conditions of the first-step chemical strengthening treatment: The time is 90 - 120 min, the temperature is 420 - 450 °C, and the alkali metal molten salt includes 25 - 60 wt% potassium nitrate and 40 - 75 wt% sodium nitrate; Conditions of the second-step chemical strengthening treatment: The time is 30 - 60 min, the temperature is 400 - 420 °C, and the alkali metal molten salt includes 96 - 98 wt% potassium nitrate and 2 - 4 wt% sodium nitrate.

[0039] During chemical strengthening, weigh analytical pure sodium nitrate and potassium nitrate in proportion and put them into a stainless steel container, heat to the set temperature to form a salt bath and then keep it warm.

[0040] Preferably, the thickness of the super-strong impact-resistant protective glass is 0.5 - 1.6 mm.

[0041] Preferably, the clarifying agent is SnO 2 .

[0042] It should be noted that the main melting method of this application can be the way of a fully electric melting furnace or the way of a flame combined with an electro-assisted melting furnace, and high-temperature annealing treatment is carried out after forming; The specific forming method can be carried out by the float method, the slot-down method, the overflow-down method or casting. The examples provided by the present invention are only for illustration and are not limited to this method.

[0043] The implementation process of the present invention will be described in detail below in conjunction with specific embodiments.

[0044] In the following examples and comparative examples, the raw materials used are all ordinary commercially available products that can be directly purchased or can be prepared according to conventional techniques in the art.

[0045] I. Examples of the preparation method of the super-strong impact-resistant protective glass of the present invention Examples 1-12 Examples 1-12 all provide protective glass; among them, the preparation method of the protective glass includes the following steps: First, according to the component ratios in Table 1 and Table 2, calculate and weigh the raw materials corresponding to each component, and mix the raw materials of each component to obtain a mixed material; secondly, put the mixed material into a platinum crucible and melt the mixed material to obtain a glass melt, wherein the melting treatment temperature is 1680 °C and the time is 8 h; then, pour the glass melt into a preheated stainless steel mold for molding; finally, wait for the glass to be molded and demolded and put it into an annealing furnace for annealing, the annealing temperature is 640 °C and the time is 28 h to obtain the protective glass.

[0046] Examples 1-12 also provide super-strong impact-resistant protective glass; among them, the preparation method of the super-strong impact-resistant protective glass includes the following steps: Cut the above-mentioned protective glass into sheet glass with a thickness of 0.7 mm and immerse it in a potassium nitrate and potassium nitrate mixed molten salt with a special ratio for the first-step chemical strengthening treatment and the second-step chemical strengthening treatment to obtain the super-strong impact-resistant protective glass. Among them, the strengthening conditions are shown in Table 3 and Table 4.

[0047] In the present application, when the annealing temperature is 600 °C or 800 °C and the time is 8 h or 48 h, the super-strong impact-resistant protective glass prepared has the same technical effect as the above examples.

[0048] In the present application, when the alkali metal molten salt is potassium nitrate or sodium nitrate, the super-strong impact-resistant protective glass prepared has the same technical effect as the above examples.

[0049] Table 1 Component ratios of the protective glass in Examples 1-6

[0050] Table 2 Component ratios of the protective glass in Examples 7-12

[0051] Table 3 Strengthening conditions of the super-strong impact-resistant protective glass in Examples 1-6

[0052] Table 4 Strengthening Conditions of Ultra-Strong Impact-Resistant Protective Glass for Examples 7-12

[0053] II. Experimental Examples The ultra-strong impact-resistant protective glass prepared in Examples 1-12 was subjected to CS, DOL, coefficient of thermal expansion, density, softening point, KIC, Young's modulus, ball-drop and whole-machine drop performance tests. Among them, CS and DOL were tested using FSM6000X and SLP2000 respectively, and the photoelastic coefficient / refractive index was 30.8 / 1.51; the coefficient of thermal expansion α was the value measured using a dilatometer, and the average value in the temperature range of 30 to 380 °C was taken; the density ρ was the value measured using the well-known Archimedes method; the softening point T s was determined according to the methods of ASTM C336 and C338; according to GB T 37900-2019, "Test Method for Hardness and Fracture Toughness of Ultra-Thin Glass - Vickers Hardness Indentation Method with Small Load", its fracture toughness was tested using the Vickers hardness indentation method; the Young's modulus E was the value measured using the resonance method. The larger the Young's modulus, the easier it is for the specific Young's modulus (Young's modulus / density) to increase. If it is in the shape of a flat plate, the self-weight makes it difficult for the glass to bend.

[0054] The chemically strengthened glass (144.98 mm × 66.78 mm × thickness) was bonded to an 180 g steel plate to fabricate a test sample. The test sample was fixed on a glass support frame, and then steel balls of the same weight were freely dropped from different heights to simulate the impact force that might be received in a real environment. According to the requirements of the IEC glass ball-drop test standard, the number of glass samples for the ball-drop test of each example was 10 pieces, and the average value of the impact force received by the glass samples was recorded. For the whole-machine drop experiment, the sandpaper used was German-made sandpaper with 180-mesh silicon carbide material. The drop test started from 200 mm and increased by 100 mm each time until the glass broke, and this height was recorded as the glass breakage height; the number of glass samples for the drop test of each example was 10 pieces, and the average value of the breakage height in the drop test was used as the average whole-machine drop breakage height. The specific test results are shown in Tables 5 and 6 as follows: Table 5 Performance Test Results of Ultra-Strong Impact-Resistant Protective Glass Prepared in Examples 1-6

[0055] Table 6 Performance Test Results of Ultra-Strong Impact-Resistant Protective Glass Prepared in Examples 7-12

[0056] As can be seen from Table 5 and Table 6, for the protective glass of the present invention, by precisely controlling the types and contents of components, and by precisely controlling the synergistic quantitative relationship between components, it is ensured that the ion exchange depth of the high-strength impact-resistant protective glass of the present invention is not less than 101 μm, reducing the strengthening difficulty. The CS of the ultra-strong impact-resistant protective glass prepared in this application is above 896 MPa, up to 1013 Mpa at most; the DOL is above 101.5 μm, up to 121.7 μm at most; the thermal expansion coefficient in the temperature range of 30 - 380 °C is lower than 66.1×10 -7 / °C, with the lowest being 57.9×10 -7 / °C; the density is above 2.38 g / cm 3 , up to 2.53 g / cm 3 at most; the softening point is between 857 - 896 °C, all less than 900 °C; the KIC is 1.1 MPa·m 1 / 2 ; the Young's modulus is above 74 Gpa, up to 81 Gpa at most; the falling ball is above 0.25 J, up to 0.4 J at most; the simulated whole-machine drop is above 1400 mm, up to 1900 mm at most.

[0057] This shows that the protective glass provided in this application can achieve good chemical strengthening by controlling the mass percentage ranges of various raw materials. The ultra-strong impact-resistant protective glass prepared using the above protective glass has the characteristics of a relatively high ion exchange layer depth, a long salt bath service life, and good impact resistance. After reprocessing, it can meet the requirements of customers for the portability of electronic products and the mechanical properties, solving the requirements for the mechanical properties of lightness and firmness of the glass cover plate, and can be used as the outer shell components of consumer electronic products such as mobile phones and tablets.

[0058] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A protective glass, characterized in that: Calculated by mass percentage, the raw materials include: 50%~65%SiO2, 20%~30%Al2O3, 0%~10%B2O3, 2%~6%Li2O, 1%~6%Na2O, 0%~4%K2O, 0%~1%MgO, 0%~2%CaO, 0%~2%SrO, 0%~2%ZnO, 0%~8%P2O5, and 0%~1% clarifier, among which Li2O+Na2O+K2O is 5%~12%, and MgO+CaO+SrO+ZnO is 0%~5%.

2. The protective glass according to claim 1, characterized in that: Among the raw materials: (Li2O+Na2O+K2O+MgO+CaO+SrO+ZnO) / Al2O3≤1.

3. The protective glass according to claim 2, characterized in that: Calculated by mass percentage, the raw materials include: 53%~63%SiO2, 22%~28%Al2O3, 0%~7%B2O3, 2%~5%Li2O, 2%~5%Na2O, 0%~2.5%K2O, 0%~1%MgO, 0%~2%CaO, 0%~1.5%SrO, 0%~1.5%ZnO, 0%~6.5%P2O5, and 0.1%~0.2% clarifier, among which Li2O+Na2O+K2O is 5%~11%, MgO+CaO+SrO+ZnO is 0.9%~4%, and (Li2O+Na2O+K2O+MgO+CaO+SrO+ZnO) / Al2O3 is 0.3~0.

6.

4. The protective glass according to claim 2, characterized in that: Calculated by mass percentage, the raw materials include: 56%~63%SiO2, 25%~27.5%Al2O3, 3%~7%B2O3, 3%~4.5%Li2O, 2.2%~3.7%Na2O, 0%~2.1%K2O, 0%~0.65%MgO, 0%~1.3%CaO, 0.1%~0.6%SrO, 0%~2.2%P2O5, and 0.12%~0.15% clarifier, among which Li2O+Na2O+K2O is 5.3%~9.2%, MgO+CaO+SrO+ZnO is 0.9%~2.1%, and (Li2O+Na2O+K2O+MgO+CaO+SrO+ZnO) / Al2O3 is 0.3~0.

5.

5. A method for preparing protective glass, characterized in that: The method comprises the following steps: according to the raw materials of the protective glass according to any one of claims 1 to 4, the raw materials are sequentially mixed, melted, molded and annealed to obtain the protective glass.

6. The method for preparing protective glass according to claim 5, characterized in that: The annealing temperature is 600-800° C. and the annealing time is 8-48 hours.

7. A super impact-resistant protective glass, characterized in that: The ultra-strong impact-resistant protective glass is formed by chemically strengthening the protective glass described in any one of claims 1 to 4 or the protective glass prepared by the method for preparing the protective glass described in any one of claims 5 to 6.

8. A method for preparing super impact-resistant protective glass, characterized in that: The method comprises the following steps: placing the protective glass described in any one of claims 1 to 4 or the protective glass prepared by the method for preparing the protective glass described in any one of claims 5 to 6 in an alkali metal molten salt for a first step chemical strengthening treatment and a second step chemical strengthening treatment to obtain the super impact-resistant protective glass.

9. The method for preparing the ultra-strong impact-resistant protective glass according to claim 8, characterized in that: The temperature of the first step chemical strengthening treatment is 400-480°C, and the time is 0.5-2h; the temperature of the second step chemical strengthening treatment is 400-450°C, and the time is 0.5-1.5h; the alkali metal molten salt is sodium nitrate molten salt or potassium nitrate molten salt or a mixed molten salt of sodium nitrate and potassium nitrate, and the mixed molten salt of sodium nitrate and potassium nitrate includes 20-100 wt% of potassium nitrate and 0-80 wt% of sodium nitrate.

10. Use of the super-strong impact-resistant protective glass as claimed in claim 7 or the super-strong impact-resistant protective glass prepared by the preparation method of the super-strong impact-resistant protective glass as claimed in claim 8 or 9 in the back cover material of display devices and mobile devices.

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