Composite fluxing agent, aluminoborosilicate glass as well as preparation method and application of aluminoborosilicate glass

Abstract

The invention discloses a composite fluxing agent, aluminoborosilicate glass as well as a preparation method and application of the aluminoborosilicate glass, and belongs to the technical field of glass. The composite fluxing agent provided by the invention can realize efficient fluxing of aluminoborosilicate glass on the premise of being more environment-friendly and lower in energy consumption, so that the prepared glass not only has excellent internal quality (extremely low bubble and knot defect rate), but also has super-hydrophilic and lasting self-cleaning functions on the surface; the preparation method disclosed by the invention is controllable in process and suitable for large-scale production, and distribution of the chlorine element in the glass can be accurately regulated and controlled, so that synergism of fluxing and hydrophilic functions is realized.

Description

Technical Field

[0001] This invention relates to the field of glass technology, specifically to a composite flux, aluminoborosilicate glass, its preparation method, and its application. Background Technology

[0002] With the rapid development of display technologies (such as smartphones, tablets, and LCD TVs), the automotive industry (automotive displays and window glass), and the new energy industry (photovoltaic module covers), the performance requirements for special glass are increasing. Modern high-end applications not only demand excellent mechanical properties (such as high hardness and high strength), thermal stability (high strain point and low coefficient of thermal expansion), and optical properties (high transmittance and low color difference), but also urgently require excellent surface functional properties, such as self-cleaning, anti-fogging, anti-fingerprint, and anti-fogging. Aluminum borosilicate glass, especially alkali-free aluminum borosilicate glass, has become one of the preferred materials for display electronic glass substrates and high-end automotive glass due to its high strain point, good chemical stability, excellent mechanical strength, and coefficient of thermal expansion matching semiconductor materials.

[0003] In the glass melting process, fluxing is a crucial step in removing air bubbles from the molten glass, directly determining the intrinsic quality and grade of the glass products. Currently, widely used fluxes in the industry mainly include sulfates, arsenic oxide, antimony oxide, cerium oxide, and tin oxide. Chinese invention patent CN117980276A discloses a clarifying bag for glass compositions, containing cerium dioxide and tin oxide, and explicitly states that the clarifying bag may be chlorine-free. This technology primarily targets borosilicate glass and aluminosilicate glass tubing used in pharmaceutical packaging (such as ampoules and vials). The patent focuses on achieving effective fluxing through the synergistic effect of CeO2 / SnO2 in specific tube drawing processes, without addressing the imparting of hydrophilic properties to the glass surface.

[0004] Furthermore, Chinese invention patent CN119330585A provides an aluminosilicate or aluminoborosilicate glass composition and products containing the same. This glass composition, by introducing a specific proportion of alkaline earth metal oxides and a low concentration of boron oxide, exhibits excellent properties such as a high annealing point (e.g., above 775°C) and high elastic modulus, making it suitable as a substrate for ultra-high resolution flat panel display devices. However, the technical focus of this patent is on improving the bulk physical and chemical properties of the glass (such as annealing point, elastic modulus, and liquidus viscosity) through composition optimization, without addressing the design of specific fluxes to achieve efficient melting while imparting a durable hydrophilic function to the glass surface.

[0005] Through in-depth analysis of existing technologies, the following technical problems that urgently need to be solved can be identified: (1) Functional singularity: Traditional flux technology mainly focuses on bubble removal efficiency, and rarely considers the influence of flux and its residual components on the final surface properties of glass. The fluxing process and surface functionalization are regarded as two independent and even contradictory process links, resulting in a complex and costly preparation process for high-performance glass.

[0006] (2) Limitations in Mechanism Understanding and Technological Bias: Existing technologies, especially in the field of high-end electronic glass, generally adopt a cautious or even avoidant attitude towards the application of chlorine. This is mainly due to the potential corrosiveness of chlorine to furnace refractory materials at high temperatures, as well as concerns about its potential to introduce impurities or lead to performance instability. Therefore, there is a widespread technological bias in the industry that the use of chlorine should be avoided or strictly limited in high-end alkali-free aluminoborosilicate glass, or it should only be used as an auxiliary flux, completely ignoring the enormous potential of chlorine in glass surface modification. There is a lack of systematic and in-depth research and understanding of the migration and segregation behavior of chloride ions during the cooling process of glass melt and their impact on surface energy.

[0007] (3) Difficulty in balancing performance: Due to the aforementioned limitations in functional singularity and mechanistic understanding, existing technologies struggle to simultaneously achieve both highly desirable properties—"efficient fluxing" (low bubble defect rate) and "durable hydrophilicity" (low and stable contact angle)—within the same glass system. Typically, achieving a low bubble rate requires high-temperature, long-duration melting, which may negatively impact the stability of surface functions; while surface modification treatments (such as coatings) may introduce new defects or reduce mechanical strength. Overcoming this technological bottleneck and achieving a balance between intrinsic quality and surface function has been a long-term goal pursued by those skilled in the art.

[0008] Therefore, developing a novel flux specifically for alkali-free aluminoborosilicate glass that can simultaneously achieve efficient fluxing and durable surface hydrophilicity, along with the corresponding glass composition and preparation method, has significant theoretical and industrial application value. Summary of the Invention

[0009] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a composite flux, aluminoborosilicate glass, its preparation method and application. This flux can achieve efficient fluxing of aluminoborosilicate glass under the premise of being more environmentally friendly and having lower energy consumption. This results in glass with not only excellent internal quality (extremely low rate of bubbles and nodules) but also superhydrophilic and long-lasting self-cleaning function on the surface. Furthermore, the preparation method of this invention is process-controllable, suitable for large-scale production, and can precisely control the distribution of chlorine in the glass, thereby achieving synergy between fluxing and hydrophilic functions.

[0010] The technical solution of this invention is as follows: In a first aspect, the present invention provides a composite flux, based on the total mass of the glass batch, composed of 0.4-5.5% calcium chloride and 0.01-0.5% tin dioxide, with a mass ratio of calcium chloride to tin dioxide of (1-20):1. This composite flux, based on chloride ion transport kinetics optimization design, can achieve staged and synergistic fluxing over a wide temperature range of 1200-1650℃. Specifically, CaCl2 dominates medium-temperature fluxing in the relatively lower temperature range of 1200-1400℃, effectively removing small bubble nuclei formed early in the melt by generating Cl2 gas through decomposition; while SnO2 dominates high-temperature deep fluxing in the higher temperature range of 1500-1650℃, releasing O2 through valence change to merge and eliminate larger bubbles.

[0011] In a second aspect, the present invention provides an aluminoborosilicate glass comprising a batch material and a composite flux as described in claim 1 or 2, wherein the batch material comprises the following components in molar percentage: SiO2 63-69%, Al2O3 7-15%, B2O3 6-17%, MgO 0.01-5%, CaO 6-10%, SrO 0.1-1.5%, BaO 0.001-1.5%, SnO2 0.005-0.35%, Cl... - 0.001-0.5%; wherein, the total content of alkali metal oxides in the glass is <0.1 mol%, and the Cl content on the glass surface (within a depth of 0.50 nm) is <0.1 mol%. - Concentration and bulk Cl - The concentration ratio is (2.5-6.75):1, indicating the presence of significant Cl. - Surface enrichment phenomenon; HCEF=Cl - ×(SiO2+Al2O3)=1-30, NSI=(SiO2+Al2O3) / (MgO+CaO+SrO+BaO)=3-40.

[0012] The design basis for the function and content of each component in this invention is as follows: SiO2 (63-69%): As the main glass network forging, it forms the basic framework of the glass. Its content is higher than 63% to ensure that the glass has high chemical stability, mechanical strength, hardness, and heat resistance (high strain point and softening point). However, a content exceeding 69% will lead to a sharp increase in the high-temperature viscosity of the glass, making melting difficult, significantly increasing energy consumption, and making it prone to crystallization.

[0013] Al2O3 (7-15%): As an amphoteric oxide, it mainly enters the glass network in this system, forming a stable [SiO4] and [AlO4] network structure together with SiO2. It can significantly improve the strain point, elastic modulus, hardness, and chemical corrosion resistance of the glass. When the content is below 7%, the network strengthening effect is insufficient; when it is above 15%, it will significantly increase the melting temperature and liquidus temperature, deteriorate the melting and forming properties, and increase the risk of crystallization.

[0014] B2O3 (6-17%): It is an important network former and an effective flux. It can significantly reduce the high-temperature viscosity of glass, improve melting and homogenization, and lower the melting temperature. B2O3 can also reduce the coefficient of thermal expansion of glass and improve its thermal stability. However, if its content is too high (e.g., close to the upper limit of 17%), attention should be paid to its volatilization at high temperatures and the potential phase separation problems it may cause.

[0015] MgO (0.01-5%): As a network oxide, its main function is to regulate the high-temperature viscosity and crystallization properties of glass. An appropriate amount of MgO can effectively reduce high-temperature viscosity and promote fluxing and homogenization. It produces a "mixed alkaline earth effect" with alkaline earth metal oxides such as CaO, which helps to inhibit crystallization and improve the forming stability of glass. A content exceeding 5% can easily lead to glass devitrification.

[0016] CaO (6-10%): Also a network excipient, it is an important component in this invention. It works synergistically with MgO to significantly improve the hardness, Young's modulus, and chemical stability of the glass while reducing high-temperature viscosity. Its content is similar to that of Cl. - The introduction of CaO (through CaCl2) is related. However, excessively high CaO content (>10%) will significantly shorten the glass's properties, which is not conducive to precision forming and may increase the coefficient of thermal expansion.

[0017] SrO (0.1-1.5%): As a network exogenous substance, its ionic radius is larger than that of Mg. 2+ and Ca 2+ Introducing SrO can further optimize the "mixed alkaline earth effect," allowing for more precise control of the glass's viscosity-temperature profile and crystallization tendency. This helps maintain good thermal stability and mechanical properties while lowering the melting temperature.

[0018] BaO (0.001-1.5%): As the alkaline earth metal oxide with the largest ionic radius, the introduction of a small amount of BaO can effectively further reduce the high-temperature viscosity of glass and significantly improve melting and fluxing effects. Simultaneously, BaO can increase the density and refractive index of glass and has a positive effect on lowering the liquidus temperature and inhibiting crystallization. Its content is controlled at a low level to avoid excessively lowering the glass strain point or significantly increasing the coefficient of thermal expansion.

[0019] SnO2 (0.005-0.35%) and Cl - (0.001-0.5%): These two are the residual components of the functional flux of this invention in the glass. SnO2 decomposes and releases O2 during the melting process, participating in high-temperature deep melting; the Cl element comes from the decomposition of CaCl2, partly escaping as Cl2 to play a role in medium-temperature melting, and partly as Cl... - The form is dissolved in the glass. This portion of the dissolved Cl... - It is key to achieving superhydrophilic surface properties. Its content range ensures fluxing effect and surface function, while avoiding excessive amounts that could lead to glass performance degradation (such as phase separation, crystallization) or excessive erosion of furnace refractory materials.

[0020] To achieve precise and predictable control over glass properties, this invention proposes two key scientific parameters: (1) Hydrophilic fluxing efficiency factor: HCEF=Cl - ×(SiO2+Al2O3) This factor comprehensively considers the two core elements for achieving dual functionality. - The content (molar percentage) is the driving force for surface segregation and the source of fluxing gas, determining the functional strength. (SiO2 + Al2O3) (molar percentage) represents the stability and strength of the glass network, which constrains the Cl... - The solid solution capacity of the glass affects its bulk properties (such as strain point and hardness). If the HCEF value is too small (<1), then Cl... - Insufficient functionality, with insignificant fluxing and hydrophilic effects; excessively high HCEF values ​​(>30) indicate excessive Cl. - It may disrupt network stability, leading to glass crystallization or decreased chemical durability.

[0021] Preferably, HCEF = 15-30. Within this range, the glass exhibits both excellent bubble removal capability and a superhydrophilic surface.

[0022] (2) Network stability index: NSI = (SiO2 + Al2O3) / (MgO + CaO + SrO + BaO) This index reflects the ratio of "network forming bodies" to "network external bodies" (modifiers) in a glass network. A higher NSI value indicates a higher degree of connectivity in the glass network and a more robust network structure.

[0023] The NSI value is closely related to a range of important properties of glass. A higher NSI typically corresponds to a higher strain point, annealing point, softening point, hardness, and chemical stability, as well as a lower coefficient of thermal expansion.

[0024] The NSI value of the glass of this invention is 3-40. By adjusting the NSI within this range, it can be ensured that the glass has good meltability while meeting the stringent requirements of high-end applications for thermal stability and mechanical strength.

[0025] Preferably, the aluminoborosilicate glass has superhydrophilicity and durability: the initial water droplet angle is 0.5°-3.5°, and after 1000h of accelerated aging test at 85°C and 85%RH, the water droplet angle is 2.6°-5.9°, showing good hydrophilic durability.

[0026] Preferably, the aluminoborosilicate glass has excellent fluxing effect and a bubble defect rate of 0.2-1.85%.

[0027] Preferably, the aluminoborosilicate glass has high mechanical strength and a Vickers hardness ≥575HV.

[0028] Preferably, the aluminoborosilicate glass possesses excellent thermal properties, with a strain point of 635-725℃, an annealing point of 635-775℃, a softening point of 965-1055℃, and a coefficient of thermal expansion of 29.6 × 10⁻⁶ in the range of 25-300℃. -7 / ℃-37.5×10 -7 / ℃, which is very suitable as a display substrate material.

[0029] Thirdly, the present invention provides a method for preparing the above-mentioned aluminoborosilicate glass, comprising the following steps: S1: The batching material and the composite flux as described in claim 1 or 2 are mixed uniformly to obtain a mixture; S2: The mixture is first heated from room temperature to 1200℃ at a rate of 8-12℃ / min to rapidly decompose the raw materials and initiate a preliminary solid-phase reaction, reducing volatilization loss; then heated to 1550℃ at a rate of 3-6℃ / min. This stage is the glass formation and main fluxing zone. CaCl2 decomposes in large quantities in this temperature range (especially 1200-1400℃), producing Cl2 gas, achieving medium-temperature fluxing; finally, the temperature is raised to 1650℃ and held for 2-4 hours. This stage is the high-temperature deep fluxing and homogenization stage. SnO2 plays a full role, releasing O2, eliminating residual large bubbles, and making the chemical composition of the glass melt highly uniform, completing fluxing and homogenization. S3: The homogenized molten glass is shaped (e.g., float glass, overflow casting, molding), and then the shaped glass product is annealed at 680-750℃ for 2-4 hours. This annealing process not only effectively eliminates the internal stress of the glass but also helps to improve its properties. - Stable migration and segregation to the surface during the later stages of cooling are crucial for the formation of a durable hydrophilic surface.

[0030] Fourthly, the present invention also provides applications of the aforementioned aluminoborosilicate glass, which is used in display device glass as cover glass or substrate glass for displays such as smartphones, tablets, laptops, and LCD TVs. Its super-hydrophilic surface provides fingerprint resistance, stain resistance, and easy cleaning, enhancing the user experience. In automotive glass, it is used in car dashboards, central control screens, head-up display systems, and side and rear windows, significantly improving driving safety through its anti-fog and self-cleaning properties. It is also used in wafer carriers and wafer sealing. In photovoltaic glass, it serves as cover glass for solar cell modules, where its self-cleaning function effectively reduces the accumulation of dust and dirt, maintaining high light transmittance and thus improving the power generation efficiency of the photovoltaic system. Finally, it is used in architectural glass for building curtain walls, doors, and windows requiring self-cleaning functions.

[0031] The Cl of the present invention - Thermodynamics and kinetics of surface segregation: (1) Thermodynamic driving force: Based on the principles of surface physicochemicals, any system has a spontaneous tendency to move towards the state of lowest surface free energy. During the cooling process of glass melt, Cl - Due to its large ionic radius and low polarizability, it forms a network with bulk ions (Si). 4+ Al 3+ The bonding energy of Cl is relatively weak, placing it in a higher energy state. - When the material migrates from the bulk phase to the surface, it significantly reduces the surface energy (γ) of the system. The thermodynamic driving force of this process can be described by the following simplified model: ΔG = ΔH - TΔS + γΔA.

[0032] Where ΔG is the Gibbs free energy change, ΔH and ΔS are the enthalpy change and entropy change, respectively, T is the temperature, and ΔA is the surface area change. For Cl - The migration towards the surface is primarily driven by the decrease in the surface energy term γΔA. In this invention, the surface Cl... - Enrichment leads to a significant reduction in surface energy, especially a substantial increase in its polar component.

[0033] Experimental verification: XPS In-Depth Analysis: Using Thermo Scientific K Alpha XPS with a monochromatic Al Kα source, and through Ar... + Ion beam sputtering was used for depth profiling to obtain the Cl element concentration from the surface to the bulk phase (depth of approximately tens of nanometers). Typical results show that the Cl concentration at the glass surface / bulk phase is... - The concentration ratio reaches (2.5-6.75):1.

[0034] Physicochemical analysis of the interface based on hydrophilic mechanism: The hydrophilicity of a glass surface is primarily determined by its surface energy, which is closely related to its chemical composition and microstructure. In this invention, Cl... - The surface enrichment achieves superhydrophilic properties through the synergistic effect of the following mechanisms: (1) Enhance surface polarity: Cl - These are strongly electronegative ions, and their enrichment on the surface greatly increases the surface polarity. According to the Owens-Wendt-Rabel-Kaeble method for surface energy, surface energy (γ) can be decomposed into a polar component (γ^p) and a dispersive component (γ^d). Experimental measurements show that the polar component of the glass surface of this invention is significantly higher than that of conventional alkali-free aluminoborosilicate glass. According to the Young Dupre equation, the solid-liquid adhesion work (W... a )for: W a = γ 1v (1 + cosθ); Where, γ 1v Let W be the surface tension of water and θ be the contact angle. A high surface polarity component leads to an adhesion work W of water on the solid surface. a The increase in the contact angle θ results in a decrease in the contact angle, which in turn enhances hydrophilicity.

[0035] (2) Promotes the formation of the hydration layer: Cl - It has a strong hydration capacity, capable of physically adsorbing water molecules from the air to form a stable, molecularly thick pre-hydrated layer on the glass surface. When a water droplet falls onto the surface, this pre-hydrated layer acts as a bridge, greatly reducing the solid-liquid interfacial tension and promoting the rapid spread of the water droplet.

[0036] (3) Microscopic roughness effect: AFM (Atomic Force Microscopy, Bruker Dimension Icon, tapping mode) measurements show that the glass surface of the present invention has a moderate nanoscale roughness (RMS = 0.8-1.2 nm). This is due to the microscopic inhomogeneity of the surface composition (Cl... - The topological structure caused by the enriched and non-enriched regions may further enhance hydrophilicity through the Wenzel effect. Meanwhile, the contact angle hysteresis (the difference between the advancing and retreating angles) is less than 5°, indicating uniform surface chemical properties.

[0037] Two-stage fluxing kinetics and hydrodynamic optimization: The composite flux (CaCl2 / SnO2) of this invention is designed based on a deep understanding of bubble behavior in different temperature ranges.

[0038] Fundamentals of bubble motion: The rising velocity of bubbles in molten glass follows a modified form of Stokes' law: v = [2r2 g(ρ1-ρ v )] / [9η] × K; Where v is the upward velocity, r is the bubble radius, g is the gravitational acceleration, ρ1, ρ v Here, η represents the density of the molten glass and the bubble, respectively; η is the viscosity of the molten glass; and K is a correction factor that takes into account factors such as interfacial tension and bubble shape.

[0039] Phased synergistic mechanism: Mid-temperature stage (1200-1400℃, CaCl2 dominant): In this temperature range, the viscosity of the molten glass remains relatively high. CaCl2 decomposes to produce a large number of tiny Cl2 bubbles (radius r = 5-20 μm). Although these small bubbles rise slowly individually, their large number and total surface area allow them to efficiently absorb and carry residual gases dissolved in the melt (such as N2 and CO2) as well as tiny bubble nuclei, thus playing a scavenging role. At the same time, the strong oxidizing property of Cl2 helps to break down some impurity clusters that cause bubbles.

[0040] High-temperature stage (1500-1650℃, SnO2 dominant): In this high-temperature range, viscosity decreases. SnO2 releases O2 through the reaction 2SnO2→2SnO+O2. These O2 bubbles are typically large (r=50-200μm), and according to Stokes' law, their rising speed is much greater than that of smaller bubbles. They can merge with small bubbles encountered along the way (including Cl2 bubbles), rapidly grow, and quickly rise to the liquid surface and rupture, achieving efficient and rapid deep fluxing.

[0041] Synergistic effect: When the mass ratio of CaCl2 to SnO2 is (1.4-50):1, the release rates of Cl2 and O2 are optimally matched (Cl2 / O2=1.2-2.5). This ensures that, across the entire fluxing temperature range, there is both a sufficient number of small bubbles for deep cleaning and a sufficient number of large bubbles for rapid removal, forming an efficient bubble removal chain, thereby reducing the bubble defect rate to an extremely low level.

[0042] Compared with the prior art, the present invention has the following advantages: 1. This invention is the first to systematically propose and experimentally verify the "dual-function theory" of chloride ions in aluminoborosilicate glass: that is, acting as a "dynamic vapor-phase flux" during the high-temperature melting stage, and acting as a "permanent hydrophilic modifier" through "surface segregation" during the cooling and application stages. This invention is the first to confirm that chloride ions... - The gradient distribution on the glass surface provides a reasonable explanation for the surface segregation phenomenon. This breaks the industry's technical prejudice that "chlorine is merely a harmful impurity or auxiliary flux in high-end glass," and innovatively transforms it into a key element for achieving high-performance surface functions.

[0043] 2. Compared to traditional chlorine-free fluxing systems (such as Sb₂O₃ and CeO₂), the composite flux of this invention significantly reduces the bubble defect rate, achieving top-tier internal glass quality. It achieves a superhydrophilic surface (water droplet angle ≤ 4°) with extremely durable hydrophilic properties; after 1000 hours of aging, the contact angle decay is minimal, and durability is significantly improved compared to traditional surface treatment techniques or comparative samples. While achieving excellent fluxing and hydrophilic properties, the aluminoborosilicate glass prepared by this invention retains the excellent characteristics of alkali-free aluminoborosilicate glass, such as a high strain point (≥ 635℃) and high hardness (≥ 575HV), successfully resolving the technical contradiction of simultaneously achieving efficient fluxing and durable hydrophilicity.

[0044] 3. This invention innovatively proposes scientific parameters such as the hydrophilic fluxing efficiency factor HCEF and the network stability index NSI, and establishes a quantitative structure-property relationship model between glass composition, structure and final performance, realizing predictable design and precise control of glass performance, and reducing the blindness of traditional trial-and-error development.

[0045] 4. The preparation method of this invention is highly compatible with traditional glass production processes, eliminating the need for complex post-processing steps (such as coating) to achieve surface functionalization, simplifying the process, reducing costs, and meeting the requirements of large-scale and stable production. Due to the synergistic effect and optimized composition of the composite flux, the melting temperature can be appropriately reduced or the holding time shortened, resulting in lower overall energy consumption. Detailed Implementation

[0046] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0047] Examples 1-16 The formulations of the aluminoborosilicate glass batches (molar percentage) and composite fluxes (mass percentage of the batches) in Examples 1-16 and Comparative Examples 1-9 are shown in Tables 1-3.

[0048] Table 1. Formulations of aluminoborosilicate glass batches and composite fluxes in Examples 1-8 Table 2. Formulations of aluminoborosilicate glass batches and composite fluxes in Examples 9-16 Table 3 Formulations of aluminoborosilicate glass batches for Comparative Examples 1-9 The preparation methods of the aluminoborosilicate glasses in Examples 1-16 and Comparative Examples 1-9 include the following steps: S1 Ingredients: According to the formula shown in Table 1, calculate and weigh the corresponding high-purity raw materials: quartz sand (SiO2), alumina (Al2O3), boric acid (H3BO3, introduced into B2O3), magnesium carbonate (MgCO3, introduced into MgO), calcium carbonate, calcium chloride (CaCO3, CaCl2, introduced into CaO), strontium carbonate (SrCO3, introduced into SrO), and barium carbonate (BaCO3, introduced into BaO); the composite flux is anhydrous calcium chloride (CaCl2) and tin dioxide (SnO2); the purity of all raw materials is ≥99.8%.

[0049] S2 Mixing: Place the weighed raw materials into a three-dimensional mixer and mix for 2 hours to ensure uniform mixing.

[0050] S3 Melting: The uniformly mixed material is placed in a platinum crucible and then placed in a high-temperature heating furnace. A stepped heating regime is adopted: the temperature is increased from room temperature to 1200℃ at a rate of 10℃ / min, then to 1550℃ at a rate of 5℃ / min, and finally to 1650℃, and held for 4 hours.

[0051] S4 Forming and Annealing: The homogenized molten glass is poured into a preheated graphite mold to form a glass plate of specified dimensions. The glass plate is then immediately transferred to an annealing furnace with a pre-set temperature and annealed at 700°C for 2 hours, and then cooled to room temperature at a rate of 0.5°C / min.

[0052] The performance of the aluminoborosilicate glasses of Examples 1-16 and Comparative Examples 1-6 was tested, and the testing and characterization methods are as follows: Hydroxyl content (%): Measured according to the method specified in GB / T 12442-2019 Test method for hydroxyl content in quartz glass.

[0053] Fusion energy consumption (kcal / kg): Measured according to the method in GB / T2589 General Rules for Calculation of Comprehensive Energy Consumption.

[0054] Bubble analysis: After cutting, grinding and polishing the glass sample, observe it under a microscope with an image analysis system, count the number of bubbles with a diameter >0.1mm per unit area, and convert them into the number of bubbles per kilogram of glass (bubbles / kg). A bubble count ≥1 per kilogram of glass is considered a defective product.

[0055] Nodule defect rate (%): Nodule defects are defined as those with a size ≥100μm.

[0056] Coefficient of thermal expansion CTE (10) -7 / ℃): Measured using a horizontal dilatometer in the range of 25-300℃, according to the method specified in ASTM E-228.

[0057] Young's modulus (GPa): Measured according to the method specified in GB / T 37780-2019.

[0058] Poisson's ratio: Measured according to the method specified in GB / T 37780-2019.

[0059] Annealing point (°C), strain point (°C), and softening point (°C): measured using a three-point tester according to the method specified in ASTM C-336.

[0060] 200P temperature (°C) and 35000P temperature (°C): The high-temperature viscosity-temperature profiles of glass were obtained by rotating a high-temperature viscometer according to the method specified in ASTM C-965; the temperature corresponding to the 200P viscosity is denoted as T. m The molding temperature corresponding to a viscosity of 35000P is denoted as T. 35000 .

[0061] Vickers hardness (HV): Determined using a microhardness tester under a load of 0.5 kgf, according to the method specified in GB / T 37900-2019.

[0062] Density (g / cm³) 3 ): Measured according to the method specified in ASTM C-693.

[0063] Thinning weight loss: The weight loss per unit area of ​​a glass substrate after immersion in a 10 wt.% HF solution for 20 minutes at 20°C is denoted as CHF and the unit is mg / cm³. 2 .

[0064] Chemical composition: The contents of elements such as Si, Al, B, Mg, Ca, Sr, Ba, and Sn in the glass phase were determined by X-ray fluorescence spectrometry.

[0065] solid phase Cl - Content: Determined by ion chromatography (instrument model: Dionex ICS-900, test standard: GB / T15453-2018). This method can accurately determine Cl in the glassy phase. - The content accuracy can reach ±0.01%.

[0066] Surface Cl - Content: Using Thermo Scientific K Alpha XPS with a monochromatic Al Kα source, via Ar + Ion beam sputtering was used for depth profiling to obtain the Cl 2p spectral line intensities at different depths, and the atomic concentration was calculated after calibration with standard samples.

[0067] Internal Cl -Content: The glass cross-section was tested using a Thermo Scientific K Alpha XPS source with a monochromatic AlKα source, and the content was determined by Ar. + Ion beam sputtering was used for depth profiling, and the intensity of Cl 2p spectral lines at different depths was used to calculate the atomic concentration after calibration with standard samples.

[0068] Water droplet angle (°): The static contact angle was measured using a Tianzheng Huayi TH-E contact angle meter and the seated drop method. The water droplet volume was 1 μL, and the static contact angle was measured 3 seconds after the water droplet came into contact with the sample surface. Five different positions were measured for each sample, and the average value was taken.

[0069] Aging test: The glass sample was placed in a constant temperature and humidity chamber at 85℃ and 85%RH, and removed at 1000h. After cooling to room temperature, the water droplet angle was measured.

[0070] The performance test and characterization results are shown in Table 4-6: Table 4 Performance test and characterization results of aluminoborosilicate glasses in Examples 1-8 Table 5 Performance test and characterization results of aluminoborosilicate glasses in Examples 9-16 Table 6 Performance test and characterization results of aluminoborosilicate glasses of Comparative Examples 1-9 The data above shows that: Cl - Correlation between surface enrichment and hydrophilicity: All examples exhibited superhydrophilicity (droplet angle ≤ 4°), while Comparative Examples 1-6, due to the absence of Cl, showed superior hydrophilicity. - The droplet angles were all above 38°, which directly proves that Cl - Surface enrichment is the fundamental reason for superhydrophilicity. XPS and droplet angle data show a significant negative correlation, verifying the presence of Cl on the surface in this application. - Concentration and bulk Cl - The characteristic is that the concentration ratio is ≥3.5.

[0071] Hydrophilicity and durability: After 1000 hours of aging testing, the contact angle of the example only increased slightly, but remained within the superhydrophilic or extremely hydrophilic range (<6°); while the comparative example showed a significant decrease in hydrophilicity. This indicates that the contact angle of the Cl-based example increased slightly, but remained within the superhydrophilic or extremely hydrophilic range (<6°). - The hydrophilic layer formed by surface segregation is part of the bulk structure and therefore has extremely high stability.

[0072] Fluxing effect: The bubble defect rate of all examples was significantly lower than that of the corresponding comparative examples, which proves that the CaCl2 / SnO2 composite flux has an overwhelming advantage in fluxing efficiency compared with single SnO2 or chlorine-free systems. The bubble defect rate of Examples 5-10, 15, and 16 was all below 1.1%, and Example 10 even reached 0.2%.

[0073] Mechanical and thermal properties: Vickers hardness ≥ 575 HV, strain point ≥ 635℃, annealing point ≥ 635℃, softening point ≥ 965℃ for all embodiments. Comparative Examples 1-6 do not contain Cl. - Its strain point and hardness are generally slightly lower than those of the corresponding embodiments, which proves the superiority of the composition design of the present invention.

[0074] To assess the industrialization potential of this invention, a verification test was conducted on a near-commercial pilot production line with a daily output of 25 tons: Yield: After 30 consecutive batches of production, the yield (the proportion of products with a bubble defect rate of ≤2% and a water droplet angle of ≤4°) remained stable between 98.5% and 99.2%, which is much higher than the 92%-95% of traditional processes.

[0075] Process capability: Statistical process control analysis was performed on key performance parameters (bubble defect rate, water droplet angle, strain point). The process capability index Cpk was greater than 1.67, indicating that the production process was stable and had the level of Six Sigma management.

[0076] Energy consumption: Due to the excellent effect of the composite flux, the melting temperature can be reduced by about 20°C, and the overall energy consumption is reduced by about 22.3% compared with the traditional process.

[0077] In summary, through scientific theoretical guidance, precise composition design, and optimized preparation process, this invention has successfully prepared a novel aluminoborosilicate glass that combines excellent intrinsic quality (low bubbles, high hardness, and high thermal stability) with durable surface functions (superhydrophilicity and self-cleaning). Its comprehensive performance is significantly superior to existing technologies, and it is ready for large-scale production and commercial application.

Claims

1. A composite flux, characterized in that, Based on the total mass of the glass batch, it consists of 0.4-5.5% calcium chloride and 0.01-0.5% tin dioxide, with the mass ratio of calcium chloride to tin dioxide being (1-20):

1.

2. An aluminoborosilicate glass, characterized in that, The mixture includes a batching material and a composite flux as described in claim 1. The batching material comprises the following components in molar percentage: SiO2 63-69%, Al2O3 7-15%, B2O3 6-17%, MgO 0.01-5%, CaO 6-10%, SrO 0.1-1.5%, BaO 0.001-1.5%, SnO2 0.005-0.35%, Cl... - 0.001-0.5%; the total content of alkali metal oxides in the glass is <0.1 mol%, and the Cl content on the glass surface is <0.1 mol%. - Concentration and bulk Cl - The concentration ratio is (2.5-6.75):1; HCEF=Cl - ×(SiO2+Al2O3)=1-30, NSI=(SiO2+Al2O3) / (MgO+CaO+SrO+BaO)=3-40.

3. The aluminoborosilicate glass as described in claim 2, characterized in that, The initial water droplet angle of the aluminoborosilicate glass is 0.5°-3.5°, and after 1000 hours of accelerated aging test at 85°C and 85%RH, the water droplet angle is 2.6°-5.9°.

4. The aluminoborosilicate glass as described in claim 2, characterized in that, The bubble defect rate of the aluminoborosilicate glass is 0.2-1.85%.

5. The aluminoborosilicate glass as described in claim 2, characterized in that, The Vickers hardness of the aluminoborosilicate glass is ≥575HV.

6. The aluminoborosilicate glass as described in claim 2, characterized in that, The aluminoborosilicate glass has a strain point of 635-725℃, an annealing point of 635-775℃, a softening point of 965-1055℃, and a coefficient of thermal expansion of 29.6×10⁻⁶ in the range of 25-300℃. -7 / ℃-37.5×10 -7 / ℃.

7. The method for preparing aluminoborosilicate glass according to claim 2, characterized in that, Includes the following steps: S1: The batching material and the composite flux as described in claim 1 are mixed uniformly to obtain a mixture; S2: First, heat the mixture from room temperature to 1200℃ at a rate of 8-12℃ / min, then heat it to 1550℃ at a rate of 3-6℃ / min, and finally heat it to 1650℃ and hold it for 2-4 hours to complete the melting and homogenization. S3: The homogenized molten glass is shaped, and then the shaped glass product is annealed at 680-750℃ for 2-4 hours.

8. The application of the aluminoborosilicate glass as described in claim 2, characterized in that, The aluminoborosilicate glass is used in display device glass, automotive glass, wafer carrier, wafer sealing, photovoltaic glass, or architectural glass.

Images