Chemically tempered ultrathin flexible glass and preparation method thereof

Abstract

The invention provides chemically tempered ultrathin flexible glass and a preparation method thereof, and belongs to the technical field of flexible glass preparation. The raw materials comprise silicon dioxide, aluminum oxide, sodium oxide, potassium oxide, cerium oxide, europium oxide, strontium oxide, magnesium oxide and antimony oxide; the raw materials comprise 60.5-78.8% of silicon dioxide, 8-12% of aluminum oxide, 10-12% of sodium oxide, 1-5% of potassium oxide, 0.5-2% of cerium oxide, 0.1-1% of europium oxide, 0.5-2% of strontium oxide, 1-5% of magnesium oxide and 0.05-0.5% of antimony oxide. The preparation method of the chemically tempered ultrathin flexible glass comprises the steps of preparing the glass substrate and performing two-stage chemical tempering. The step of preparing the glass substrate comprises the steps of raw material melting and clarifying, pull-down forming and pre-cooling annealing; the two-stage chemical tempering comprises the steps of low-temperature pre-exchange and high-temperature deep tempering. The product provided by the invention has good barrier effect on harmful blue light while giving consideration to both flexibility and high strength.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible glass preparation, and in particular to a chemically tempered ultra-thin flexible glass and a preparation method thereof. Background Art

[0002] With the advancement of science and technology, flexible display devices are gradually becoming popular as a means of conveying information. For example, a large number of mobile phones and other communication devices featuring foldable, rotating, and scrollable screens have emerged on the market, as well as wearable devices such as VR glasses, AR glasses, and smart watches and bracelets. These devices have greatly enriched people's entertainment activities and broadened their access to information. However, the advancement of digitalization also means that people's eyes are exposed to blue light emitted by various display devices for a long time. High-energy visible light in the blue-violet spectrum (wavelength 385-445nm) is potentially harmful to the human eye and is a major cause of eye diseases such as chronic retinal damage. Among the currently popular blue light blocking products, some are not effective in filtering blue light, and some even cause color cast and dimming of the screen, further exacerbating eye fatigue.

[0003] The prior art with publication number CN119735364A discloses a production and preparation process for ultra-thin flexible glass. Through tempering treatment, a compressive stress layer is formed on the glass surface, which significantly improves the strength and impact resistance of the glass; the prior art with publication number CN118684438A discloses a chemically tempered flexible ultra-thin glass, which has high flexibility, thermal shock resistance, and scratch resistance compared to traditional flexible glass; the prior art with publication number CN113511812B discloses an ultra-thin flexible electronic glass and a preparation method thereof. By optimizing the formula and processing conditions, the compressive stress on the glass surface is reduced and the elastic modulus is increased, thereby improving the flexibility of the glass; the relevant technologies have all strengthened the mechanical properties of flexible glass in different directions, but rarely involve research related to blocking harmful blue light.

[0004] From the above, it can be seen that the flexible glass involved in the existing technology still has the technical problem of not being able to have both excellent mechanical properties and high blue light protection performance. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a chemically tempered ultra-thin flexible glass and a preparation method thereof, and achieves the following invention objectives: to prepare a tempered ultra-thin flexible glass with high strength, impact resistance, protection against harmful blue light, and high light transmittance.

[0006] To achieve the above objectives, the technical solutions adopted are as follows: A chemically tempered ultra-thin flexible glass, the raw materials of which include: silicon dioxide (SiO2), aluminum oxide (Al2O3), sodium oxide (Na2O), potassium oxide (K2O), cerium oxide (CeO2), europium oxide (Eu2O3), strontium oxide (SrO), magnesium oxide (MgO), and antimony oxide (Sb2O3); The raw materials are mixed in the following proportions: 60.5-78.8% silicon dioxide, 8-12% aluminum oxide, 10-12% sodium oxide, 1-5% potassium oxide, 0.5-2% cerium oxide, 0.1-1% europium oxide, 0.5-2% strontium oxide, 1-5% magnesium oxide, and 0.05-0.5% antimony oxide; all percentages are by mass.

[0007] Preferably, the raw material ratio is: 65.4-69.3% silicon dioxide, 10.1-11% aluminum oxide, 11.1-11.6% sodium oxide, 2.7-4.7% potassium oxide, 1-1.6% cerium oxide, 0.3-0.4% europium oxide, 0.5-1% strontium oxide, 3.8-5% magnesium oxide, and 0.3-0.4% antimony oxide.

[0008] A method for preparing chemically tempered ultra-thin flexible glass, comprising preparing a glass substrate and a two-stage chemical tempering step; The preparation of the glass substrate includes the steps of melting and clarifying raw materials, down-drawing and forming, and pre-cooling and annealing.

[0009] The raw materials are melted and clarified: the raw materials are weighed, mixed and transferred into a high-temperature furnace, melted and clarified to form a uniform glass liquid, and then enter the down-draw molding step.

[0010] Furthermore, the melting temperature is 1650~1750℃, and the melting time is 12~18h.

[0011] The down-draw forming process involves introducing the molten glass from a high-temperature furnace into a down-draw roller system, where the molten glass is drawn downward by the rollers to form a glass substrate.

[0012] Furthermore, the thickness of the formed glass substrate is 100±5 μm.

[0013] The pre-cooling annealing: the formed glass substrate is first cooled in a pre-cooling area, and then enters an annealing area for 30 to 60 minutes.

[0014] Furthermore, the pre-cooling area is gradually cooled from 800°C to 600°C.

[0015] Furthermore, the temperature of the annealing zone is 400-500°C.

[0016] The two-stage chemical tempering includes low-temperature pre-exchange and high-temperature deep tempering steps.

[0017] The low-temperature pre-exchange comprises immersing the glass substrate in pre-exchange molten salt and treating the glass substrate at 360-380° C. for 0.5-2 hours.

[0018] The high temperature deep tempering process involves immersing the glass substrate in deep tempering molten salt and treating the glass substrate at 420-450° C. for 2-6 hours.

[0019] Furthermore, the pre-exchange molten salt components are: KNO3 80~85%, NaNO3 11~15%, Ce(NO3)3 3~6%.

[0020] Furthermore, the deep tempering molten salt components are: KNO3 95~99%, Sr(NO3)2 1~5%.

[0021] Compared with the prior art, the present invention has achieved the following beneficial effects: The present invention provides a chemically tempered ultra-thin flexible glass, the surface compressive stress of which can reach up to 997MPa and the maximum bending radius is ≤4.0mm. While having excellent strength and bending performance, it can also effectively block harmful blue light. DETAILED DESCRIPTION

[0022] To make the purpose, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0023] Example 1 A method for preparing chemically tempered ultra-thin flexible glass Step 1: Prepare glass substrate Raw material ratio: silicon dioxide 60.5%, aluminum oxide 12%, sodium oxide 12%, potassium oxide 5%, cerium oxide 2%, europium oxide 1%, strontium oxide 2%, magnesium oxide 5%, and antimony oxide 0.5%.

[0024] 1. Raw material melting and clarification: According to the weight ratio of the above-mentioned materials, weigh them and put them into a blender to mix evenly. After mixing, transfer them into a high-temperature furnace for melting and clarification to form a uniform glass liquid. The melting temperature is 1750°C and the melting time is 12 hours; then enter the down-draw molding step.

[0025] 2. Down-draw molding: The glass liquid is introduced from the high-temperature furnace into the down-draw roller system, and is stretched downward by the rollers to form a glass substrate with a thickness of 100±5μm.

[0026] 3. Pre-cooling annealing: The formed glass substrate is first cooled in the pre-cooling area, where the temperature gradually decreases from 800°C to 600°C; the cooled glass substrate then enters the annealing area, where the temperature is 400°C and the annealing time is 30 minutes.

[0027] Step 2: Two-stage chemical tempering 1. Low-temperature pre-exchange: Immerse the annealed glass substrate in pre-exchange molten salt and treat it at 360°C for 2 hours.

[0028] The distribution ratio of the pre-exchange molten salt components is: KNO3 85%, NaNO3 11%, Ce(NO3)3 4%, and the percentages are all mass percentages.

[0029] 2. High temperature deep tempering: Immerse the pre-exchanged glass substrate in deep tempering molten salt and treat it at 450℃ for 6 hours.

[0030] The composition ratio of the deep tempering molten salt is: KNO3 95.5%, Sr(NO3)2 4.5%, and the percentages are all by mass.

[0031] Following the steps of Example 1, only the raw material ratios and process parameters were changed to carry out Examples 2 to 9. The raw material ratios and some process parameters used in Examples 2 to 9 are shown in Table 1.

[0032] Table 1 Raw material ratios and process parameters of chemically tempered ultra-thin flexible glass

[0033] Note: All percentages are by mass.

[0034] Comparative Example 1 Step 1: Prepare glass substrate Raw material ratio: silicon dioxide 69%, aluminum oxide 10.5%, sodium oxide 10.5%, potassium oxide 2.5%, cerium oxide 1%, europium oxide 0.2%, strontium oxide 1.5%, magnesium oxide 4.6%, and antimony oxide 0.2%.

[0035] 1. Raw material melting and clarification: Weigh the materials according to the ratio and put them into the blender to mix evenly. After mixing, transfer them into the high-temperature furnace to melt and clarify to form a uniform glass liquid. The melting temperature is 1680℃ and the melting time is 12h. Then enter the down-draw molding step.

[0036] 2. Down-draw molding: The glass liquid is introduced from the high-temperature furnace into the down-draw roller system, and is stretched downward by the rollers to form a glass substrate with a thickness of 100±5μm.

[0037] 3. Pre-cooling annealing: The formed glass substrate is first cooled in the pre-cooling area, where the temperature gradually decreases from 800°C to 600°C. The cooled glass substrate then enters the annealing area, where the temperature is 450°C and the annealing time is 40 minutes.

[0038] Step 2: Two-stage chemical tempering 1. Low-temperature pre-exchange: Immerse the annealed glass substrate in pre-exchange molten salt and treat it at 380°C for 2 hours.

[0039] The distribution ratio of the pre-exchange molten salt components is: KNO3 84%, NaNO3 16%, and the percentages are all mass percentages.

[0040] 2. High temperature deep tempering: Immerse the pre-exchanged glass substrate in deep tempering molten salt and treat it at 430℃ for 4 hours.

[0041] Deep tempering molten salt component ratio: KNO3 100%, all percentages are by mass.

[0042] Following the steps of Comparative Example 1, only the raw material ratios and some process parameters were changed to carry out Comparative Examples 2 to 5. The raw material ratios and process parameters used in Comparative Examples 2 to 5 are shown in Table 1.

[0043] Table 2 Raw material ratio and process parameters used in the comparative example

[0044] Note: All percentages are by mass.

[0045] Performance Testing The glasses prepared in Examples 1 to 9 of the present invention were subjected to performance tests, and the test results are shown in Table 3.

[0046] The glasses prepared in Comparative Examples 1 to 5 of the present invention were subjected to performance tests, and the test results are shown in Table 4.

[0047] The test methods used are as follows: Bending fatigue times: tested in accordance with GB / T 44752-2024 "Flexible glass bending fatigue test method".

[0048] Limit bending radius: tested using GB / T 38686-2020 "Ultra-thin glass flexibility test method two-point bending method".

[0049] Surface stress: Tested using ASTM C1422 / C1422M-20 Standard Specification for Chemically Tempered Flat Glass.

[0050] Blue light transmittance: tested using GB / T 38120-2019 "Technical Requirements for Light Health and Light Safety Application of Blue Light Protective Film".

[0051] Light transmittance: The test is conducted using the light transmittance determination method in ASTM E903-20 "Standard Test Method for Solar Absorption, Reflection, and Transmittance of Materials Using an Integrating Sphere".

[0052] Table 3 Performance test results of the glasses prepared in Examples 1-9

[0053] Table 4 Performance test results of the glasses prepared in Comparative Examples 1 to 5

[0054] According to Tables 3 and 4, the surface compressive stress of the chemically tempered ultra-thin flexible glass prepared in Examples 1 to 9 reaches 847 to 997 MPa, and the ultimate bending radius is ≤4.0 mm, which indicates that it has both excellent strength and flexibility. The chemically tempered ultra-thin flexible glass prepared in Examples 1 to 9 has a blue light transmittance of 12.0 to 19.2% at 385 to 415 nm and a blue light transmittance of 15.3 to 20.6% at 415 to 445 nm, indicating that it has a good blue light blocking effect in the 385 to 445 nm band.

[0055] Unless otherwise specified, the percentages described in the present invention are all percentages by mass, and the ratios described are all mass ratios. Obviously, under the concept of the present invention, there are many specific implementation methods that can be varied, and the embodiments listed in the present invention are only some preferred embodiments. It should be stated here that any changes made under the inventive concept of the present invention will fall within the scope of protection of the present invention.

Claims

1. A chemically tempered ultra-thin flexible glass, characterized by: The raw materials include silicon dioxide, aluminum oxide, sodium oxide, potassium oxide, cerium oxide, europium oxide, strontium oxide, magnesium oxide, and antimony oxide; the ratio of the raw materials is: silicon dioxide 60.5-78.8%, aluminum oxide 8-12%, sodium oxide 10-12%, potassium oxide 1-5%, cerium oxide 0.5-2%, europium oxide 0.1-1%, strontium oxide 0.5-2%, magnesium oxide 1-5%, and antimony oxide 0.05-0.5%; the percentages are all by mass.

2. The chemically tempered ultra-thin flexible glass according to claim 1, characterized in that: The raw material ratio is: 65.4-69.3% silicon dioxide, 10.1-11% aluminum oxide, 11.1-11.6% sodium oxide, 2.7-4.7% potassium oxide, 1-1.6% cerium oxide, 0.3-0.4% europium oxide, 0.5-1% strontium oxide, 3.8-5% magnesium oxide, and 0.3-0.4% antimony oxide.

3. The method for preparing chemically tempered ultra-thin flexible glass according to any one of claims 1 and 2, characterized in that: The method comprises the steps of preparing a glass substrate and two-stage chemical tempering; the preparation of the glass substrate comprises the steps of melting and clarifying raw materials, down-drawing, and pre-cooling annealing; the raw material melting and clarification comprises weighing the raw materials, mixing them evenly, transferring them into a high-temperature furnace, melting and clarifying them to form a uniform glass liquid, and then entering the down-drawing step; the melting temperature is 1650-1750°C, and the melting time is 12-18 hours.

4. The method for preparing chemically tempered ultra-thin flexible glass according to claim 3, wherein: The down-draw forming process involves introducing the molten glass from a high-temperature furnace into a down-draw roller system, where the molten glass is drawn downward by the rollers to form a glass substrate.

5. The method for preparing chemically tempered ultra-thin flexible glass according to claim 3, wherein: The pre-cooling annealing: the formed glass substrate is first cooled in a pre-cooling area, starting from 800° C. and gradually cooled to 600° C., and then enters an annealing area for 30 to 60 minutes.

6. The method for preparing chemically tempered ultra-thin flexible glass according to claim 3, wherein: The two-stage chemical tempering includes low-temperature pre-exchange and high-temperature deep tempering steps; The low-temperature pre-exchange process comprises immersing the glass substrate in pre-exchange molten salt and treating the pre-exchange molten salt at 360-380° C. for 0.5-2 hours.

7. The method for preparing chemically tempered ultra-thin flexible glass according to claim 6, wherein: The pre-exchange molten salt composition is KNO3 80-85%, NaNO3 11-15%, and Ce(NO3)3 3-6%.

8. The method for preparing chemically tempered ultra-thin flexible glass according to claim 6, wherein: The high temperature deep tempering process involves immersing the glass substrate in deep tempering molten salt and treating the glass substrate at 420-450° C. for 2-6 hours.

9. The method for preparing chemically tempered ultra-thin flexible glass according to claim 8, characterized in that: The deep tempering molten salt composition is KNO3 95-99%, Sr(NO3)2 1-5%.

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