Method for improving bending strength of flexible glass

Abstract

The invention discloses a method for improving the bending strength of flexible glass, and relates to the technical field of flexible glass surface defect control. The method comprises the following steps: depositing based on a magnetron sputtering technology to form nano-particle distribution which is gradually changed from bottom to top; stress is dispersed through gradually changing material properties, and the bending strength of the flexible glass is improved. The coating is deposited through the magnetron sputtering technology, and nano-particle distribution gradually changing from bottom to top is formed, so that stress during bending is dispersed, and microcracks are reduced. Meanwhile, a low-temperature annealing process is combined, so that the residual stress is further reduced. The Al2O3 nanoparticles are used to form gradient distribution in the coating, the bottom is tightly combined with the glass substrate, and the top provides hardness, so that the generation of cracks is reduced. The bending strength of the flexible glass is effectively improved, and a feasible and simple operation method is provided for application and development of the flexible glass.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of defect control of flexible glass surface, in particular to a method for improving the bending strength of flexible glass. BACKGROUND

[0002] The vigorous rise of flexible electronics is reshaping human-computer interaction and information display at an unprecedented speed. For example, foldable smartphones realize physical opening and closing of the screen, scrollable displays provide variable display area, and wearable health monitoring devices need to closely fit complex curved surfaces of the human body. These revolutionary application scenarios have put forward extreme requirements for core window materials, which must be "both rigid and flexible":

[0003] They not only need to have excellent optical transparency, surface hardness, scratch resistance, gas barrier property and chemical stability of traditional glass, but also must have mechanical flexibility similar to polymers, such as repeated bending or even folding. Ultra-thin flexible glass is considered as an ideal candidate material for realizing the next generation of flexible electronic products due to its unparalleled comprehensive performance advantages.

[0004] However, when the glass is made to an extreme thinness to give it sufficient bending ability, its inherent brittle fracture nature is dramatically amplified, resulting in insufficient bending strength as the core bottleneck restricting its large-scale commercial application. The internal reasons and limitations of existing strengthening techniques are as follows:

[0005] The basic structural unit of flexible glass is a strong covalent bond connected silicon-oxygen tetrahedral network, forming a rigid three-dimensional skeleton. This structure gives it high hardness and chemical stability, but also brings a fatal weakness: lack of plastic deformation ability. Under stress, glass cannot dissipate energy through dislocation slip like metal or molecular chain rearrangement like polymer. Stress is highly concentrated at any small defect in the structure (such as surface scratches, internal inclusions, micro-cracks), which easily reaches the theoretical breaking strength of the material;

[0006] The strength of glass is theoretically high, but the actual strength is much lower than the theoretical value, which is mainly due to surface and near-surface defects such as micro-cracks. The proportion of surface area contained in unit volume increases dramatically, meaning that the negative impact of surface defects (such as micro-scratches and edge collapse generated during processing and handling) on overall strength is significantly amplified. When the ultra-thin sheet is bent, the neutral layer is closer to the surface, making the surface bear more tensile stress.

[0007] Currently, chemical strengthening is the most mature technique to improve the mechanical strength of glass. The principle is to immerse the glass into a molten salt bath, and drive the small ions in the surface layer of the glass to exchange with the larger ions in the molten salt at high temperature (usually > 400℃). After cooling, the surface layer contains a compressive stress layer due to the accommodation of larger ions, and the interior generates a corresponding tensile stress to balance it. This compressive stress layer can effectively inhibit the opening and expansion of surface micro-cracks, thereby improving the strength and impact resistance.

[0008] However, ultra-thin glass has a very high specific surface area and a very low heat capacity, and at a processing temperature of 400℃ or even higher, it is extremely easy to soften and deform, warp, or even collapse. The viscosity of the glass decreases sharply with increasing temperature, and at high temperatures required for ion exchange, the gravity of the glass substrate itself or slight stress from the supporting clamp can cause irreversible dimensional changes and surface flatness degradation, which is fatal for display applications that require high flatness.

[0009] In addition, surface coatings (such as polymers, hard coatings) can provide some scratch resistance and toughening effect, but it is often difficult to form a coating that is thick enough and firmly bonded on ultra-thin glass without affecting the optical properties or increasing the thickness / stiffness, and the coating itself may crack or peel off under repeated bending. Alternatively, laminated structures can improve impact resistance and breakage safety by laminating flexible glass with polymer films, but they cannot fundamentally improve the bending strength of the glass substrate itself, and cracks can still occur and expand within the glass layer. Lamination also increases the complexity and thickness of the overall structure.

[0010] In summary, due to the fact that the most effective chemical strengthening technique must rely on a high-temperature processing process that is extremely prone to cause unacceptable thermal deformation of ultra-thin glass, while facing a series of insurmountable disadvantages such as difficulty in optimizing the matching of stress layer depth and substrate thickness, high risk of stress relaxation, and complex and expensive process, the present application provides a method for improving the bending strength of flexible glass. SUMMARY

[0011] The present application aims to provide a method for improving the bending strength of flexible glass, which forms a gradually changing nanoparticle distribution from the bottom to the top by magnetron sputtering technology, thereby dispersing the stress during bending and reducing micro-cracks, solving the problem of poor bending strength of existing flexible glass.

[0012] To solve the above technical problems, the present application is realized by the following technical scheme:

[0013] The present application is a method for improving the bending strength of flexible glass, comprising the following steps:

[0014] Mixing isopropanol aluminum with anhydrous ethanol, then adding deionized water and stirring, adjusting PH to 4-6 with dilute nitric acid, grinding after water bath, drying and cooling to obtain Al2O3 nanoparticles;

[0015] Hydrophobic modification of Al2O3 nanoparticles with anhydrous ethanol and 3-methacryloxypropyltrimethoxysilane;

[0016] Through a multi-target magnetron sputtering system, the power of the Al2O3 nanoparticle target is adjusted every 10 minutes, the target power is 50-200 W, the polyimide target is turned on at a constant power of 100 W, the sputtering deposition time is 0-60 minutes, and a deposition coating with a total thickness of 2-5 μm is sputtered on the flexible glass in steps; a continuous PI matrix phase is formed, which wraps the Al2O3 nanoparticles to form a stress buffer layer, avoiding stress concentration caused by Al2O3 agglomeration;

[0017] After being kept at 100-400℃ for 2 hours, the product is obtained after natural cooling.

[0018] Further, it also includes the pretreatment of flexible glass, and the pretreatment method includes:

[0019] Put the flexible glass into the ethanol solution for ultrasonic cleaning to remove surface oil, dust and other impurities, then wash with deionized water and dry in a constant temperature oven for standby.

[0020] Further, the flexible glass includes the following raw materials in weight ratio:

[0021] SiO2: 55-65%, Al2O3: 16-25%, Na2O: 5-12%, K2O: 1-5%, MgO: 5-10%, ZrO2: 0-2%.

[0022] Further, when mixing isopropanol aluminum with anhydrous ethanol, the molar ratio is 1:10, the deionized water added satisfies the molar ratio of water to aluminum of 50:1, and the stirring conditions are magnetic stirring at room temperature for 30 minutes.

[0023] Further, the method for adjusting PH with dilute nitric acid is:

[0024] Add 0.1M dilute nitric acid drop by drop to adjust PH to 4-6 to control the hydrolysis rate.

[0025] Further, the method for obtaining Al2O3 nanoparticles after sealing, water bath, drying and cooling is:

[0026] After adjusting PH, seal and place in a 60℃ constant temperature water bath for 24 hours to form a transparent sol;

[0027] Dry in an 80℃ oven for 12 hours to obtain a white gel powder;

[0028] The powder is placed in a muffle furnace, heated to 500 DEG C at a rate of 5 DEG C / min, and kept for 2 hours, and then ground after natural cooling to obtain Al2O3 nanoparticles.

[0029] Further, the particle size of the Al2O3 nanoparticles is 20-50 nm.

[0030] Further, the method for hydrophobically modifying the Al2O3 nanoparticles comprises:

[0031] The Al2O3 nanoparticles are dispersed in anhydrous ethanol with a concentration of 10 wt%, 3-methacryloxypropyltrimethoxysilane (MPTS) is added, and stirred at 60 DEG C under reflux for 4 hours;

[0032] After reflux, the obtained solution is centrifuged at 8000 rpm for 10 minutes, and then washed with ethanol for 3 times;

[0033] Then, it is placed in a vacuum dryer at 60 DEG C for 12 hours to obtain the hydrophobically modified Al2O3 nanoparticles.

[0034] Further, the finished product is obtained after natural cooling at 150 DEG C for 2 hours.

[0035] Further, the deposition concentration is 10%-50%, and the total volume of the Al2O3 nanoparticles in the coating gradually changes from 50% to 10% from the bottom to the top of the coating.

[0036] The present application has the following beneficial effects:

[0037] The present application disperses stress by gradually changing material properties through the design of a gradient coating, and improves the bending strength of flexible glass. The coating is deposited by magnetron sputtering technology, and forms a gradually changing nanoparticle distribution from the bottom to the top, thereby dispersing stress during bending and reducing micro-cracks. At the same time, combined with a low-temperature annealing process, the residual stress is further reduced. Al2O3 nanoparticles are used to form a gradient distribution in the coating, the bottom is tightly combined with the glass substrate, and the top provides hardness, thereby reducing crack generation. The bending strength of the flexible glass is effectively improved, and a feasible and simple operation method is provided for the application and development of flexible glass.

[0038] Of course, any product implementing the present application does not necessarily need to achieve all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0040] Fig. 1 Flow chart of the method for improving the bending strength of flexible glass of the present application;

[0041] Fig. 2 Coating diagram corresponding to the embodiment of the method for improving the bending strength of flexible glass of the present application. DETAILED DESCRIPTION

[0042] In the following description, for the purpose of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0043] It should be understood that the term "comprising" as used in the specification and the appended claims indicates the presence of the recited features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0044] It should also be understood that the term "and / or" as used in the specification and the appended claims, means any one or more of the associated listed items, as well as all possible combinations of the items.

[0045] As used in the specification and the appended claims, the term "if' can be interpreted as meaning "when" or "once" or "in response to a determination" or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if detected [the described condition or event]" can be interpreted to mean "once determined" or "in response to a determination" or "once detected [the described condition or event]" or "in response to detecting [the described condition or event]" depending on the context.

[0046] In addition, in the description of the present application and the appended claims, the terms "first", "second", "third", etc. are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0047] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0048] Please see Figs. 1-2 As shown, this invention provides a method for improving the bending strength of flexible glass. Considering the stress concentration on the surface of flexible glass during bending, which may lead to microcracks, this invention designs a gradient coating to disperse stress through gradually changing material properties. The coating is deposited using magnetron sputtering technology, forming a gradually changing nanoparticle distribution from bottom to top, thereby dispersing stress during bending and reducing microcracks. Simultaneously, a low-temperature annealing process is combined to further reduce residual stress. The gradient distribution of nanoparticles in the coating, with a tight bond between the bottom and the glass substrate, and the top providing hardness, effectively reduces crack formation. This method effectively improves the bending strength of flexible glass, providing a feasible and simple operating method for the application and development of flexible glass. Specifically, it includes the following steps:

[0049] Aluminum isopropoxide was mixed with anhydrous ethanol, then deionized water was added and stirred. The pH was adjusted to 4-6 with dilute nitric acid. After sealing, the mixture was dried and cooled in a water bath before grinding to obtain Al2O3 nanoparticles with a particle size of 20-50 nm.

[0050] Al₂O₃ nanoparticles were hydrophobically modified with anhydrous ethanol and 3-methacryloxypropyltrimethoxysilane. The resulting Al₂O₃ nanoparticles were dispersed in 10 wt% anhydrous ethanol, and 3-methacryloxypropyltrimethoxysilane (MPTS) was added. The mixture was refluxed and stirred at 60 °C for 4 hours. After reflux, the resulting solution was centrifuged at 8000 rpm for 10 minutes, washed three times with ethanol, and then vacuum dried at 60 °C for 12 hours to obtain hydrophobically modified Al₂O₃ nanoparticles. Treatment with MPTS silane coupling agent can prevent nanoparticle aggregation and enhance the interfacial bonding with the PI matrix. By using a gradient doping process, the concentration gradient distribution of nanoparticles can be dynamically adjusted by sputtering power, which can effectively inhibit crack propagation.

[0051] Through the multi-target magnetron sputtering system, the Al2O3 nanoparticle target power is adjusted once every 10 minutes, the target power is 50-200 W, the polyimide target is started at a constant power of 100 W, the sputtering deposition time is 0-60 minutes, the total thickness of the deposited coating on the flexible glass is 2-5 microns, the deposition concentration is 10%-50%, and the Al2O3 nanoparticles account for 50%-10% of the total volume of the coating from the bottom to the top of the coating; the Al2O3 target and the PI target are started at the same time during sputtering to prepare a PI-Al2O3 composite coating rather than simple deposition, the PI target is constant at 100 W to form a continuous phase, and the Al2O3 target power is changed to form a gradient dispersed phase, which can maintain flexibility and realize surface strengthening.

[0052] After being kept at 100-400 DEG C for 2 hours and naturally cooled, the finished product is obtained.

[0053] As an embodiment provided by the application, preferably, the power switching adopts ramp transition, for example, when the power is changed from 50 W to 80 W, the power is gradually changed at a rate of 6 W / min to avoid the concentration mutation and the interface stress concentration.

[0054] A method for improving the bending strength of flexible glass, a gradient coating is designed to disperse stress through gradually changing material properties. The coating is deposited by magnetron sputtering technology to form a gradually changing nanoparticle distribution from the bottom to the top, thereby dispersing the stress when bending and reducing micro-cracks. At the same time, a low-temperature annealing process is combined to further reduce residual stress. Al2O3 nanoparticles are used to form a gradient distribution in the coating, the bottom is tightly combined with the glass substrate, and the top provides hardness to improve the bending strength of the flexible glass, thereby reducing crack generation. The bending strength of the flexible glass is effectively improved, and a feasible and simple operation method is provided for the application and development of flexible glass.

[0055] Example 1:

[0056] As an embodiment provided by the application, preferably, the application is a method for improving the bending strength of flexible glass, comprising the following steps:

[0057] The flexible glass sample is selected and placed in an ethanol solution for ultrasonic cleaning to remove surface oil, dust and other impurities, then washed with deionized water, and dried in a constant temperature oven for standby.

[0058] Aluminum isopropoxide (Al(OCH(CH3)2)3) was mixed with anhydrous ethanol in a 1:10 molar ratio, deionized water was added (water: aluminum molar ratio = 50:1), and the mixture was stirred magnetically at room temperature for 30 minutes. Dilute nitric acid (0.1 M) was added dropwise to adjust the pH to 4-6 to control the hydrolysis rate. After sealing, the mixture was placed in a 60°C constant-temperature water bath for 24 hours to form a transparent sol; the sol was then dried in an 80°C oven for 12 hours to obtain a white gel powder. The powder was placed in a muffle furnace and heated at a rate of 5°C / min to 500°C, and held at this temperature for 2 hours. After natural cooling, the product was ground to obtain Al2O3 nanoparticles with a particle size of 20-50 nm.

[0059] The obtained Al2O3 nanoparticles were dispersed in anhydrous ethanol at a concentration of 10 wt%, and 3-methacryloxypropyltrimethoxysilane (MPTS) was added. The mixture was stirred at reflux at 60°C for 4 hours. After refluxing, the obtained solution was centrifuged at 8000 rpm for 10 minutes, washed with ethanol three times, and the obtained sample was placed in a vacuum oven at 60°C for 12 hours to obtain hydrophobically modified Al2O3 nanoparticles.

[0060] A multi-target magnetron sputtering system was used to adjust the Al2O3 target power every 10 minutes to 50-200 W, and the deposition time was 0-60 minutes to achieve gradient doping of the nanoparticles; the substrate material was polyimide (PI) to provide flexibility, the PI target power was constant at 100 W, the total thickness of the coating was controlled at 3 μm, and after deposition, the sample was held at 150°C for 2 hours and then naturally cooled to obtain the sample.

[0061] Example 2:

[0062] As an embodiment provided by the present application, preferably, the present application is a method for improving the bending strength of flexible glass, comprising the following steps:

[0063] A flexible glass sample was selected and placed in an ethanol solution for ultrasonic cleaning to remove surface oil, dust and other impurities, and then washed with deionized water and dried in a constant-temperature oven for standby use.

[0064] Aluminum isopropoxide (Al(OCH(CH3)2)3) was mixed with absolute ethanol in a 1:10 molar ratio, deionized water was added, and the mixture was stirred magnetically at room temperature for 30 minutes. Dilute nitric acid (0.1 M) was added dropwise to adjust the pH to >7. After sealing, the mixture was placed in a 60 °C constant temperature water bath for 1-6 hours to form a transparent sol; then the mixture was dried in an 80 °C oven for 12 hours to obtain a white gel powder. The powder was placed in a muffle furnace, heated at a rate of 5 °C / min to 650 °C, and held at 650 °C for 2 hours. After natural cooling, the mixture was ground to obtain Al2O3 nanoparticles with a particle size of 50-100 nm. The obtained Al2O3 nanoparticles were dispersed in absolute ethanol with a concentration of 10 wt%, 3-methacryloxypropyltrimethoxysilane (MPTS) was added, and the mixture was stirred at reflux at 60 °C for 4 hours. After the reflux was completed, the obtained solution was centrifuged at 8000 rpm for 10 minutes, then washed with ethanol 3 times, and the obtained sample was placed in a vacuum drying oven at 60 °C for 12 hours to obtain hydrophobically modified Al2O3 nanoparticles.

[0065] A multi-target magnetron sputtering system was used, the power of the Al2O3 target was adjusted every 10 minutes to 50-200 W, the deposition time was 0-60 minutes, and the gradient doping of the nanoparticles was achieved; the substrate material was selected to be polyimide (PI) to provide flexibility, and the PI target power was constant at 100 W. The total thickness of the coating was controlled to be 3 μm. After the deposition was completed, the sample was naturally cooled after being held at 150 °C for 2 hours to obtain the sample.

[0066] Example 3:

[0067] As an embodiment provided by the present application, preferably, the present application is a method for improving the bending strength of flexible glass, comprising the following steps:

[0068] The flexible glass sample was selected, placed in an ethanol solution, and ultrasonically cleaned to remove surface oil, dust, and other impurities, then washed with deionized water, and dried in a constant temperature oven for standby use.

[0069] Aluminum isopropoxide (Al(OCH(CH3) v )3) was mixed with absolute ethanol in a 1:10 molar ratio, deionized water was added (water:aluminum molar ratio = 50:1), and the mixture was stirred magnetically at room temperature for 30 minutes. Dilute nitric acid (0.1 M) was added dropwise to adjust the pH to 4-6 to control the hydrolysis rate. After sealing, the mixture was placed in a 60 °C constant temperature water bath for 24 hours to form a transparent sol; then the mixture was dried in an 80 °C oven for 12 hours to obtain a white gel powder. The powder was placed in a muffle furnace, heated at a rate of 5 °C / min to 500 °C, and held at 500 °C for 2 hours. After natural cooling, the mixture was ground to obtain Al2O3 nanoparticles with a particle size of 20-50 nm.

[0070] The obtained Al2O3 nanoparticles were dispersed in anhydrous ethanol with a concentration of 10wt%, 3-methacryloxypropyltrimethoxysilane (MPTS) was added, and reflux stirring was carried out at 60°C for 4 hours. After the reflux was completed, the obtained solution was centrifuged at 8000 rpm for 10 minutes, then washed with ethanol for 3 times, and the obtained sample was placed in a vacuum drying oven at 60°C for 12 hours to obtain hydrophobic modified Al2O3 nanoparticles.

[0071] A multi-target magnetron sputtering system was used, the power of the Al2O3 target was adjusted every 10 minutes, the target power was 50-200 W, the deposition time was 0-240 minutes, the gradient doping of the nanoparticles was realized, the real-time monitoring was carried out through a crystal oscillator film thickness instrument, and different thicknesses of the coating were controlled; the substrate material was selected to be polyimide (PI) to provide flexibility, and the PI target power was constant at 100 W. The total thickness of the coating was controlled to be 5 μm. After the deposition was completed, the sample was obtained after being naturally cooled after being kept at 150°C for 2 hours.

[0072] Example 4:

[0073] As an embodiment provided by the present application, preferably, the present application is a method for improving the bending strength of flexible glass, comprising the following steps:

[0074] The flexible glass sample was selected and placed in an ethanol solution for ultrasonic cleaning to remove surface oil stains, dust and other impurities, then washed with deionized water, and dried in a constant temperature oven for standby use.

[0075] Aluminum isopropyl alcohol (Al(OCH(CH3)2)3) was mixed with anhydrous ethanol at a molar ratio of 1:10, deionized water was added (water:aluminum molar ratio = 50:1), and magnetic stirring was carried out at room temperature for 30 minutes. 0.1M dilute nitric acid was added dropwise, and the PH was adjusted to 4-6 to control the hydrolysis rate. After sealing, it was placed in a 60°C constant temperature water bath for 24 hours to form a transparent sol; then dried in an 80°C oven for 12 hours to obtain a white gel powder. The powder was placed in a muffle furnace, heated to 500°C at a rate of 5°C / min, kept for 2 hours, naturally cooled, and ground to obtain Al2O3 nanoparticles with a particle size of 20-50 nm.

[0076] The obtained Al2O3 nanoparticles were dispersed in anhydrous ethanol with a concentration of 10wt%, 3-methacryloxypropyltrimethoxysilane (MPTS) was added, and reflux stirring was carried out at 60°C for 4 hours. After the reflux was completed, the obtained solution was centrifuged at 8000 rpm for 10 minutes, then washed with ethanol for 3 times, and the obtained sample was placed in a vacuum drying oven at 60°C for 12 hours to obtain hydrophobic modified Al2O3 nanoparticles.

[0077] A multi-target magnetron sputtering system was used, the power of the Al2O3 target was adjusted every 10 min, the target power was 50-200 W, the deposition time was 0-60 min, the gradient doping of nanoparticles was realized; the substrate material was polyimide (PI) to provide flexibility, the PI target power was constant at 100 W. The total thickness of the coating was controlled at 3 μm. After deposition, the sample was obtained by performing shaping annealing at 550 °C.

[0078] Comparative Example 1:

[0079] A method for improving the bending strength of flexible glass, a flexible glass sample was selected and placed in an ethanol solution for ultrasonic cleaning to remove surface oil, dust and other impurities, then washed with deionized water, and dried in a constant temperature oven for standby.

[0080] Aluminum isopropyl alcohol (Al(OCH(CH3) v )3) was mixed with anhydrous ethanol at a molar ratio of 1:10, deionized water was added (water: aluminum molar ratio = 50:1), and magnetic stirring was performed at room temperature for 30 minutes. 0.1M dilute nitric acid was added dropwise, and the pH was adjusted to 4-6 to control the hydrolysis rate. After sealing, it was placed in a 60°C constant temperature water bath for 24 hours to form a transparent sol; then dried in an 80°C oven for 12 hours to obtain a white gel powder. The powder was placed in a muffle furnace, heated to 500°C at a rate of 5°C / min, and held for 2 hours, then naturally cooled and ground to obtain Al2O3 nanoparticles with a particle size of 20-50 nm.

[0081] The obtained Al2O3 nanoparticles were dispersed in anhydrous ethanol with a concentration of 10wt%, 3-methacryloxypropyltrimethoxysilane (MPTS) was added, and stirring was performed at 60°C for 4 hours. After refluxing, the obtained solution was centrifuged at 8000 rpm for 10 minutes, then washed with ethanol 3 times, and the obtained sample was placed in a 60°C vacuum drying oven for 12 hours to obtain hydrophobic modified Al2O3 nanoparticles.

[0082] The Al2O3 powder was mixed with ethanol and ammonium polyacrylate at a content of 30wt% to obtain an Al2O3 slurry. The Al2O3 slurry was uniformly sprayed on the treated flexible glass substrate by spraying. After vacuum drying in a 60°C oven for 2 hours, it was transferred to a muffle furnace and heated to 500°C at a rate of 5°C / min, and cured for 2 hours to obtain Comparative Sample 1.

[0083] For Examples 1-4 above, the sample prepared in Comparative Example 1:

[0084] The obtained samples were subjected to the bending strength test according to the unified reference standard GB / T 4740-2024. The obtained glass samples (Examples 1-4, Comparative Example 1) were placed in an oven at a temperature of 110°C, dried to a constant weight, and then placed in a desiccator and cooled to room temperature. The sample was then placed on the supporting knife edges, the distance between the supporting knife edges was adjusted so that the length of the sample outside the supporting knife edges was 10 mm, the two supporting knife edges were in the same plane and parallel to each other, and the loading knife edge was located in the middle of the two supporting knife edges. The bending strength tester was started, and the loading was applied at an average speed of 10 N / s-50 N / s until the sample was broken. The maximum load at the time of sample breakage was recorded. The width and thickness of the sample at the breakage were measured with a vernier caliper, accurate to 0.1 mm. The bending strength was calculated according to Formula 1. The obtained sample bending strength test results are shown in Table 1.

[0085]

[0086] Table 1: Sample Bending Strength Test Results

[0087]

[0088]

[0089] The stress is dispersed by gradually changing the material properties. The coating is deposited by a magnetron sputtering technique, forming a gradually changing nanoparticle distribution from the bottom to the top, thereby dispersing the stress when bending and reducing microcracks. At the same time, combined with a low-temperature annealing process, the residual stress is further reduced. The bending strength of the flexible glass is effectively improved, providing a feasible and simple operation method for the application and development of flexible glass.

[0090] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0091] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details of the application, nor limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the contents of the specification. The embodiments are chosen and described in order to better explain the principles and actual application of the application, so that those skilled in the art can better understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. A method for improving the bending strength of flexible glass, characterized in that, Includes the following steps: Aluminum isopropoxide was mixed with anhydrous ethanol, then deionized water was added and stirred. The pH was adjusted to 4-6 with dilute nitric acid, sealed, and then ground after water bath, drying, and cooling to obtain Al2O3 nanoparticles. Al2O3 nanoparticles were hydrophobically modified with anhydrous ethanol and 3-methacryloyloxypropyltrimethoxysilane. Using a multi-target magnetron sputtering system, the power of the Al2O3 nanoparticle target is adjusted every 10 minutes to make the target power 50-200W and the polyimide target is turned on with a constant power of 100W. The sputtering deposition time is 0-60 minutes, and a deposition coating with a total thickness of 2-5μm is deposited on the flexible glass by step sputtering. The finished product is obtained by holding the product at 100-400℃ for 2 hours and then allowing it to cool naturally.

2. The method for improving the bending strength of flexible glass according to claim 1, characterized in that, It also includes the pretreatment of flexible glass, and the pretreatment methods include: Take flexible glass and immerse it in an ethanol solution for ultrasonic cleaning to remove surface oil and dust. Then rinse it with deionized water and dry it in a constant temperature oven for later use.

3. A method for improving the bending strength of flexible glass according to claim 1 or 2, characterized in that, Flexible glass comprises the following raw materials in the following weight ratios: SiO2: 55~65%, Al2O3: 16~25%, Na2O: 5~12%, K2O: 1~5%, MgO: 5~10%, ZrO2: 0~2%.

4. The method for improving the bending strength of flexible glass according to claim 1, characterized in that, When aluminum isopropoxide is mixed with anhydrous ethanol, the molar ratio is 1:10, and the added deionized water satisfies the water:aluminum molar ratio of 50:

1. The stirring conditions are: magnetic stirring at room temperature for 30 minutes.

5. The method for improving the bending strength of flexible glass according to claim 1, characterized in that, The method for adjusting pH using dilute nitric acid is as follows: Add 0.1M dilute nitric acid dropwise to adjust the pH to 4-6.

6. The method for improving the bending strength of flexible glass according to claim 1, characterized in that, The method for obtaining Al2O3 nanoparticles by sealing, water bath, drying, cooling, and then grinding is as follows: After adjusting the pH, seal the container and place it in a 60℃ constant temperature water bath for 24 hours to form a transparent sol. Drying in an oven at 80°C for 12 hours yields a white gel powder; The powder was placed in a muffle furnace and heated to 500°C at a rate of 5°C / min. The temperature was maintained for 2 hours, and the powder was ground after natural cooling to obtain Al2O3 nanoparticles.

7. A method for improving the bending strength of flexible glass according to claim 1 or 6, characterized in that, The particle size of Al2O3 nanoparticles is 20–50 nm.

8. The method for improving the bending strength of flexible glass according to claim 1, characterized in that, Methods for hydrophobic modification of Al2O3 nanoparticles include: Al2O3 nanoparticles were dispersed in 10wt% anhydrous ethanol, and 3-methacryloyloxypropyltrimethoxysilane was added. The mixture was then refluxed and stirred at 60°C for 4 hours. After reflux, the resulting solution was centrifuged at 8000 rpm for 10 minutes and then washed three times with ethanol. The particles were then dried under vacuum at 60°C for 12 hours to obtain hydrophobically modified Al2O3 nanoparticles.

9. A method for improving the bending strength of flexible glass according to claim 1, characterized in that, The finished product is obtained by holding the product at 150℃ for 2 hours and then allowing it to cool naturally.

10. A method for improving the bending strength of flexible glass according to claim 1, characterized in that, The deposition concentration is 10% to 50%, and the proportion of Al2O3 nanoparticles in the total volume of the coating gradually changes from 50% to 10% from the bottom to the top of the coating.

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