Preparation method of anti-burst glass

Abstract

The invention discloses a preparation method of anti-burst glass, which comprises the following steps: arranging a first layer of glass, a second layer of glass and a polyurethane layer, taking the first layer of glass as an inner layer of laminated glass, modifying the polyurethane layer, and dispersing stress as an impact dispersion layer, a magnetic field is used for inducing a Fe3O4 nano-particle self-assembled grid and a honeycomb foaming structure to realize multi-stage energy dissipation, reducing local stress concentration, preventing overall brittle fracture of the glass, enabling the glass to still keep integrity after fracture and preventing fragments from flying off, and introducing asymmetric prestress distribution and stress concentration design into the second layer of glass, so that the strength of the second layer of glass is improved, and the service life of the second layer of glass is prolonged. Impact energy is concentrated to a preset point, so that the glass fragments can further generate impact force to crush the polyurethane layer and the first layer of glass, external impact can rapidly break through the laminated glass, the fragments fall off, a rapid access channel is provided for rescue workers, and the rescue efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of glass preparation, and particularly to a method for preparing explosion-proof glass. Background Art

[0002] With the development of society, glass, as a widely used material in fields such as architecture, transportation, and household appliances, its safety issues have attracted increasing attention. Although traditional glass performs excellently in terms of transparency, strength, etc., when subjected to external impacts or pressures, it is prone to breakage, generating a large number of sharp glass fragments. The scattering of these fragments not only poses serious safety hazards but may also cause harm to the human body or surrounding objects. Especially in application scenarios such as high-rise buildings, vehicle windows, airplane windows, and transportation, the harm of broken glass to personnel and the environment is more prominent.

[0003] Existing explosion-proof glass technologies mostly improve the impact resistance and anti-fragmentation performance of glass by means such as sandwich design, toughening treatment, and toughening materials. Common explosion-proof glasses include tempered glass and laminated glass. Tempered glass increases its surface stress through special heating and rapid cooling treatments, enabling it to break into small particles when subjected to external force impacts, reducing harm. However, once tempered glass breaks, the entire glass will quickly shatter, causing relatively large fragments and making it difficult to effectively prevent the scattering of fragments. Laminated glass, on the other hand, sandwiches a plastic film (such as PVB film, EVA film, etc.) between two layers of glass, enabling the glass to remain integral after breakage and preventing the scattering of fragments. Although laminated glass performs excellently in preventing the scattering of fragments, its impact resistance is still limited. Especially when subjected to strong impacts, the glass layer may break, and the sandwich film may not be able to effectively withstand the strong impact, resulting in the glass fragments still falling.

[0004] In order to prevent the glass from breaking and falling from a height due to internal personnel colliding with the glass, high-altitude glass needs to ensure that the glass remains integral after breakage. And in some special situations (such as fires), during high-altitude rescue by rescue personnel, it is necessary to crush the glass from the outside to make the glass completely break and fall. If the glass remains integral after being broken outside, it will affect the rescue speed.

[0005] Therefore, it is necessary to design a method for preparing explosion-proof glass on how to improve the impact resistance of glass, enhance the fragment control ability after glass breakage, and maintain good protection effects under different impact directions. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides a method for preparing explosion-proof glass.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing explosion-proof glass, comprising the following steps: Step S1: Mix silicon dioxide, sodium oxide, calcium oxide, aluminum oxide, and potassium carbonate evenly in proportion, and heat until in a molten state to obtain a liquid glass matrix; Step S2: Divide the liquid glass matrix into two parts, subject one part of the liquid glass matrix to a forming process to obtain the first layer of glass; Step S3: Apply a directional stress to the other part of the liquid glass matrix to form a stress concentration layer to obtain the second layer of glass; Step S4: Prepare a polyurethane layer as an impact dispersion layer, and press the first layer of glass and the second layer of glass together with the polyurethane layer to prepare laminated glass.

[0008] In a preferred embodiment of the present invention, in the step S1, select raw materials for the glass substrate, including 100 parts by weight of quartz sand, 15 - 20 parts of sodium oxide, 10 - 15 parts of calcium oxide, 5 - 12 parts of potassium carbonate, and 1.5 - 5.5 parts of aluminum oxide.

[0009] In a preferred embodiment of the present invention, in the step S1, add 0.1 - 0.2 parts of sodium nitrate and 0.5 - 1 part of carbon powder to the raw materials for the glass substrate and mix evenly, and melt at 1550 - 1600 °C for 4 - 6 h to obtain a liquid glass matrix.

[0010] In a preferred embodiment of the present invention, in the step S2, the forming process includes the following steps: Step S21: Introduce the liquid glass matrix into a forming mold and flatten it by gravity to form a flat glass; Step S22: Cool the flat glass at a rate of 3 °C / min to 300 - 350 °C; Step S23: Immerse the flat glass in a KNO3 molten salt bath at 400 - 450 °C for 6 - 8 h for ion exchange; Step S24: Cool the flat glass after ion exchange is completed to room temperature at a rate of 10 °C / min, and ultrasonically clean it with deionized water to remove surface salt residues to obtain the first layer of glass.

[0011] In a preferred embodiment of the present invention, in the step S23, the composition of the KNO3 molten salt includes: KNO3 and NaNO3; and the mass ratio between KNO3 and NaNO3 is 95 - 97:3 - 5.

[0012] In a preferred embodiment of the present invention, in the step S3, it includes the following sub - steps: Step S31: Introduce the liquid glass matrix into a forming mold and flatten it by gravity to form a flat glass; Step S32: Immerse side A of the flat glass in a KNO3 molten salt bath at 450°C - 480°C for 6 - 8 h to form a deep high potassium ion concentration gradient of 65 - 80 μm; Step S33: Immerse side B of the flat glass in a KNO3 molten salt bath with a mass ratio of KNO3 to NaNO3 of 95:3 between 350°C - 380°C for 2 - 2.5 h to form a shallow uniform potassium ion permeation layer of 15 - 20 μm; Step S34: Position the center of side A of the flat glass after ion exchange at a preset stress concentration point; Step S35: Cool side A of the flat glass after completing step S34 by high - speed nitrogen jet with a wind speed of 25 - 30 m / s and a cooling rate of 100 - 120°C / s, and cool side B by natural convection with a cooling rate of 40 - 50°C / s to form an asymmetric stress distribution layer, obtaining the second - layer glass.

[0013] In a preferred embodiment of the present invention, in the step S34, the setting of the stress concentration point includes: etching an array of micro - holes in the central area of side A of the flat glass with femtosecond laser at a wavelength of 1030 nm. Among them, each micro - hole is a conical structure with a diameter of 45 - 50 μm and a depth of 95 - 100 μm, uniformly arranged in a hexagonal symmetric distribution pattern, and the center - to - center distance between adjacent micro - holes is 480 - 500 μm.

[0014] In a preferred embodiment of the present invention, in the step S4, preparing the polyurethane layer includes the following steps: Step S41: Mix polyether polyol and isocyanate in a mass ratio of 1 - 2:1.5 - 4 and react at 50 - 65°C to generate a polyurethane prepolymer containing dynamic bonds; Step S42: Add an amphiphilic block copolymer, nanocrystalline cellulose whiskers and Fe 3 O 4 particles to the polyurethane prepolymer, and mix at a rotation speed of 2000 rpm for 30 - 35 min to obtain a mixed slurry; Step S43: Inject the mixed slurry into a mold and place it in a uniform magnetic field of 0.5 - 0.8 T to drive the Fe 3 O 4 particles to align along the magnetic induction lines, driving the nanocrystalline cellulose whiskers to form a grid - like structure; Step S44: Add azodicarbonamide and raise the temperature to 75 - 85°C to generate honeycomb pores, inducing the self - assembly of the amphiphilic copolymer at the gas - liquid interface to form a three - dimensional interpenetrating network, forming an impact - dispersion layer; Step S45: Regionally regulate the ultraviolet intensity, cure at 110 - 125°C for 1.5 - 2 h, and anneal for 24 h to obtain the polyurethane layer.

[0015] In a preferred embodiment of the present invention, the thickness of the first layer of glass is 5.8-6.2 mm, the thickness of the second layer of glass is 5.8-6.2 mm, and the thickness of the polyurethane layer is 0.7-1.2 mm.

[0016] In a preferred embodiment of the present invention, in step S4, a polyurethane layer is placed between a first layer of glass and a second layer of glass, and laminated glass is prepared by vacuum hot pressing.

[0017] The present invention solves the defects existing in the background technology and has the following beneficial effects: (1) The present invention provides a method for preparing explosion-proof glass, which uses ion exchange strengthening treatment to introduce potassium ions into the surface layer of the glass to form a high surface compressive stress layer, thereby improving the impact resistance and preventing slight impact from causing breakage. Through asymmetric prestress distribution, ion penetration layers of different depths are formed on both sides of the glass, and differential cooling is used to form a stress gradient inside the glass. When impacted, the cracks can be guided to expand in a directional manner to prevent overall breakage. At the same time, an impact dispersion layer is added to quickly absorb and diffuse stress, prevent glass fragments from splashing, and maintain the integrity of the glass. The nano-enhanced network in the impact dispersion layer further enhances the adhesion and avoids the risk of broken glass falling.

[0018] (2) The present invention provides a method for preparing explosion-proof glass, comprising arranging a first layer of glass, a second layer of glass and a polyurethane layer, wherein the first layer of glass is used as the inner layer of the laminated glass, and the polyurethane layer is modified and arranged as an impact dispersion layer and a diffusion stress layer, and a magnetic field is induced to induce Fe 3 O 4 The nanoparticle self-assembled grid and honeycomb foaming structure realize multi-level energy dissipation, reduce local stress concentration, prevent the overall brittle fracture of the glass, and significantly improve the adhesion and toughness of the dispersion layer, so that the glass can still maintain its integrity after breaking and prevent fragments from flying. The second layer of glass is introduced into an asymmetric prestressed distribution, and a shallow high-pressure stress gradient is formed through short-term ion exchange at low temperature on the A side, while a deep uniform compressive stress is formed on the B side through long-term high-temperature treatment. Combined with the preset micropore array etched by laser, the impact energy is concentrated to the preset point, so that the glass fragments can further generate impact force, shatter the polyurethane layer and the first layer of glass, so that the external impact can quickly penetrate the laminated glass and cause the fragments to fall, providing a quick entry channel for rescue personnel and improving rescue efficiency.

[0019] (3) The present invention drives Fe under magnetic field induction 3 O 4 The particles drive the nanocellulose whiskers to align along the direction of the magnetic flux lines, thus forming a grid-like structure inside the material. When impacted, it can quickly disperse the external force and transfer the impact energy along the nanofibers and Fe 3 O4 Chain-like path conduction between particles effectively reduces local stress concentration, thereby enhancing the overall impact resistance and dispersion performance. At the same time, by introducing azodicarbonamide blowing agent, micron-scale honeycomb pores are generated during the heating and foaming stage, enabling the amphiphilic block copolymer to self-assemble at the gas-liquid interface to form a three-dimensional interpenetrating network, which firmly locks the glass fragments when the glass breaks, endowing the polyurethane layer with strong adhesion ability and effectively preventing the fragments from falling off.

[0020] (4) In the present invention, by adopting an asymmetric prestress distribution and stress concentration design for the second-layer glass, a stress gradient structure is formed. During an external impact, the prestress distribution can transfer the external force inward and concentrate it at specific stress concentration points of the glass, inducing a strong local stress concentration effect when the glass breaks. This breaking point will further transfer stress in the direction of the impact, thereby triggering a larger range of glass breakage, effectively enhancing the overall destructive force, driving the entire interlayer to break and causing the glass fragments to fall off, thus ensuring the smooth opening of the rescue passage. At the same time, the impact direction of the glass fragments is controlled to avoid the danger caused by the fragments falling from a high altitude. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings; Figure 1 It is a flowchart of a preparation method for an explosion-proof glass of the present invention. Detailed Embodiments

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0023] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0024] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as limiting the protection scope of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0025] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood through specific circumstances.

[0026] As Figure 1 shown, a method for preparing explosion-proof glass includes the following steps: Step S1: Mix silicon dioxide, sodium oxide, calcium oxide, aluminum oxide, and potassium carbonate evenly in proportion and heat until in a molten state to obtain a liquid glass matrix; Step S2: Divide the liquid glass matrix into two parts, perform a shaping process on one part of the liquid glass matrix to obtain the first layer of glass; Step S3: Apply a directional stress to the other part of the liquid glass matrix to form a stress concentration layer to obtain the second layer of glass; Step S4: Prepare a polyurethane layer as an impact dispersion layer, and press the first layer of glass and the second layer of glass together with the polyurethane layer to prepare laminated glass; In the present invention, the thickness of the first layer of glass is 5.8 - 6.2 mm, the thickness of the second layer of glass is 5.8 - 6.2 mm, and the thickness of the polyurethane layer is 0.7 - 1.2 mm.

[0027] In the step S1, raw materials for the glass substrate are selected, including 100 parts by weight of quartz sand, 15 - 20 parts of sodium oxide, 10 - 15 parts of calcium oxide, 5 - 12 parts of potassium carbonate, and 1.5 - 5.5 parts of aluminum oxide. Sodium nitrate (0.1 - 0.2 parts) and carbon powder (0.5 - 1 part) are added to the raw materials for the glass substrate and mixed evenly. Then, they are melted at 1550 - 1600 °C for 4 - 6 h to obtain a liquid glass matrix. During the melting stage, sodium nitrate and carbon powder can be added. The role of sodium nitrate is to help improve the fluidity of the glass matrix, while the carbon powder helps reduce the viscosity of the glass during melting and is beneficial to improving the surface flatness of the glass.

[0028] Silicon dioxide: sourced from Jiangsu Lianrui New Materials Co., Ltd., with a purity of ≥99.5% Sodium oxide: sourced from Jiangsu Bost Chemical Technology Co., Ltd., with a purity of 80% Calcium oxide: sourced from Anhui Conch Cement Co., Ltd., with a purity of ≥98% Aluminum oxide: sourced from Aluminum Corporation of China Limited, with a purity of ≥99.9% Potassium carbonate: sourced from Qinghai Salt Lake Industry Co., Ltd., with a purity of ≥99% and a Cl⁻ content of ≤0.01% Carbon powder: sourced from Shanghai Haoyue Electric Furnace Technology Co., Ltd., HY - CP200 (high - purity carbon powder, with an ash content of ≤0.5%) Sodium nitrate: sourced from Shanghai Merck Chemical Technology Co., Ltd., with a purity of ≥98.5%.

[0029] In the step S2, the liquid glass matrix obtained in the step S1 is evenly divided into two parts, and the two parts of the liquid glass matrix are formed by different forming processes. One part of the liquid glass matrix is formed to obtain the first - layer glass. The forming process of the first - layer glass includes the following steps: Step S21: The liquid glass matrix is introduced into a forming mold and flattened by gravity to form a flat glass; Step S22: The flat glass is cooled at a rate of 3 °C / min to 300 - 350 °C to slowly release the internal stress of the glass evenly and avoid residual stress concentration; Step S23: The flat glass is immersed in a KNO3 molten salt bath at 400 - 450 °C for 6 - 8 h for ion exchange; By immersing the flat glass in a KNO3 molten salt bath at 400 - 450 °C, the surface strength of the glass is enhanced. Through the exchange with potassium ions in the molten salt, a high - pressure stress layer will be formed on the glass surface, thereby improving its impact resistance and crack resistance. The ion - exchange process lasts for 6 - 8 hours to ensure that potassium ions can fully penetrate the glass surface and form a relatively deep potassium - ion enrichment layer; Step S24: The flat glass after ion exchange treatment needs to be slowly cooled again to avoid thermal stress caused by excessive temperature difference. Cool the flat glass after ion exchange to room temperature at a rate of 10 °C / min. After the ion exchange is completed, a certain amount of salt will adhere to the glass surface, especially the unreacted KNO3 or its by-products. To remove these residual salts, ultrasonic cleaning with deionized water is used, which can effectively remove the salt stains on the glass surface and prevent them from affecting the subsequent processes.

[0030] The composition of the KNO3 molten salt includes: KNO3 and NaNO3; and the mass ratio between KNO3 and NaNO3 is 95 - 97:3 - 5.

[0031] In the present invention, in the said step S3, the following sub-steps are included: Step S31: Introduce the liquid glass matrix into the forming mold and flatten it by gravity to form a flat glass. Step S32: Immerse side A of the flat glass in a KNO3 molten salt bath at 450 °C - 480 °C for 6 - 8 h. Through ion exchange with potassium ions in the molten salt, a deep high-potassium ion concentration gradient will be formed on the glass surface and last for 6 - 8 hours to ensure that potassium ions penetrate deep enough on the surface of side A of the glass to form a relatively strong compressive stress layer, which helps the glass maintain structural stability during the subsequent cooling process and avoid cracks on the surface. Among them, the main purpose of the shallow high-potassium ion concentration gradient is to introduce compressive stress on the glass surface and enhance the impact resistance and crack resistance of the glass. The introduction of potassium ions will cause compressive stress on the glass surface, thereby improving its crack resistance. Step S33: Different from the treatment of side A, a deeper ion exchange treatment is carried out on side B (i.e., the other side of the glass). Immerse side B of the flat glass in a KNO3 molten salt bath at 350 °C - 380 °C with a mass ratio of KNO3 to NaNO3 of 95:3 for 2 - 2.5 h to form a 15 - 20 μm shallow and uniform potassium ion penetration layer. This process aims to make potassium ions penetrate deeply into side B of the glass, making the compressive stress layer on side B of the glass deeper and more uniform, thereby greatly improving the overall compressive resistance and crack resistance of the glass. The deep high-potassium ion concentration helps guide cracks to expand along the stress gradient when the glass is impacted, rather than resulting in a sudden breakthrough of cracks. Step S34: Center side A of the flat glass after the ion exchange is completed at a preset stress concentration point to help guide the impact energy to a specific preset point, so that the glass is more likely to break along the predetermined path under an external force. Step S35: Use high-speed nitrogen jet to cool the A side of the flat glass that has completed Step S34 at a wind speed of 30 m / s and a cooling rate of 120 °C / s to ensure that the surface of the A side cools rapidly and forms a relatively high surface stress. The B side is cooled by natural convection at a cooling rate of 50 °C / s, so that different-depth stress layers are generated on the A side and the B side, thereby forming an asymmetric stress distribution in the glass and forming an asymmetric stress distribution layer to obtain the second layer of glass. Among them, the rapid cooling of the A side will form a surface compressive stress layer, while the slow cooling of the B side will form a deeper tensile stress layer. The asymmetric stress distribution can guide the impact force to the preset stress concentration point when the glass is externally impacted, thereby achieving the effect of positioning and breaking, and further generating an impact force to crush the polyurethane layer and the first layer of glass, enabling the external impact to quickly penetrate the laminated glass and causing the fragments to fall, providing a fast entry channel for rescue personnel and improving the rescue efficiency.

[0032] In the present invention, in the step S34, the setting of the stress concentration point includes: using femtosecond laser with a wavelength of 1030 nm to etch an array of microholes in the central area of the A side of the flat glass. Each microhole is a conical structure with a diameter of 45 - 50 μm and a depth of 95 - 100 μm, and is uniformly arranged in a hexagonal symmetric distribution pattern, and the center distance between adjacent microholes is 480 - 500 μm.

[0033] The setting of the microhole array plays a role in guiding the cracking path. When the glass is impacted, cracks usually expand along the positions of the microholes. As stress concentration points, the microholes can concentrate the external impact energy on the microholes, so that the cracks expand along these microholes, effectively preventing the glass from having disordered crack expansion, ensuring that the cracks expand along the predetermined path, thereby avoiding the generation of irregular cracks in the glass under external force, and being able to generate a greater impact force when broken. When the glass is impacted by external factors without the need to break the glass, the setting and arrangement of the microholes can not only guide the expansion of cracks, but also absorb the external impact energy to a certain extent and slow down the energy transfer speed, thereby improving the impact resistance of the glass. Under the action of external force, cracks will first expand from the microholes and will not directly penetrate the entire glass surface, avoiding the instantaneous fragmentation of the glass under external impact and ensuring the toughness of the glass.

[0034] It should be noted that by controlling the arrangement and depth of the microholes, the glass can show a certain predetermined cracking mode when broken. Therefore, when broken, the fragments can spread along the path in the impact direction, avoiding the fragments from scattering or falling randomly and causing harm to the surrounding environment and personnel. Moreover, the design of the microholes can make the glass break into smaller fragments under the action of external force instead of large pieces, ensuring that the broken glass is easier to control.

[0035] In the present invention, in the step S4, preparing a polyurethane layer includes the following steps: Step S41: Polyether polyol and isocyanate are mixed in a mass ratio of 1 - 2:1.5 - 4 and reacted at 50 - 65 °C to generate a polyurethane prepolymer containing dynamic bonds. Specifically, the dynamic bond is formed by the reaction of the hydroxyl group in the polyether polyol with the isocyanate group in the isocyanate to form a urethane bond. This prepolymer has certain elasticity and adhesiveness and can better bond with the glass layer; Step S42: Add an amphiphilic block copolymer, nanocellulose whiskers and Fe 3 O 4 particles to the polyurethane prepolymer and mix at a speed of 2000 rpm for 30 - 35 min to obtain a mixed slurry; Nanocellulose whiskers can improve the toughness and adhesiveness of the polyurethane layer and enhance the strength of the overall structure; By introducing Fe 3 O 4 particles, Fe 3 O 4 particles are induced to arrange in the prepolymer under a magnetic field to form a grid-like structure, which can enhance the conductivity and magnetism of the polyurethane layer and also play a positive role in absorbing impact energy; Step S43: Inject the mixed slurry into a mold and place it in a uniform magnetic field of 0.5 - 0.8 T to drive Fe 3 O 4 particles to align along the magnetic induction lines, driving the nanocellulose whiskers to form a quasi-grid structure, which can effectively disperse the impact force and enhance the overall toughness of the material; Step S44: Add azodicarbonamide and raise the temperature to 75 - 85 °C to generate honeycomb pores, inducing the self-assembly of the amphiphilic copolymer at the gas-liquid interface to form a three-dimensional interpenetrating network and form an impact dispersion layer; Step S45: Regionally regulate the ultraviolet intensity, cure at 110 - 125 °C for 1.5 - 2 h and anneal for 24 h to obtain the polyurethane layer.

[0036] Polyether polyol: Polyoxypropylene glycol is selected, sourced from Wanhua Chemical Group Co., Ltd. (model: PPG - 2000); Isocyanate: Toluene diisocyanate is selected, sourced from Cangzhou Dahua Co., Ltd. (model: TDI - 80); The amphiphilic block copolymer is specifically: polyethylene glycol - b - polypropylene glycol - b - polyethylene glycol, sourced from Beijing Research Institute of Chemical Industry, Sinopec (model: F127); The size of the nanocellulose whiskers is 20 ± 5 nm in diameter and 1.2 ± 0.3 μm in length, sourced from Shandong Quanlin Paper Co., Ltd.; Fe 3 O 4Particles: sourced from Shanghai Aladdin Biochemical Technology Co., Ltd., with a particle size of 50 - 100 nm and a purity of ≥99.9%.

[0037] Among them, the polyurethane layer, as the interlayer in laminated glass, has extremely strong impact dispersion ability. When the glass is impacted by external factors without being broken, the polyurethane layer can quickly absorb the impact energy and spread it throughout the layer, thereby reducing the local impact force on the glass surface and enabling the overall structure of the glass to maintain a high impact resistance. Even when encountering a large impact, the glass will break locally rather than shatter completely, thus ensuring that when the glass inside a high-rise building is impacted and broken, through the adhesive property of the polyurethane layer, the glass can still remain intact as a whole, effectively maintaining the adhesion of the glass fragments, preventing the fragments from flying, and avoiding the harm caused by the fragments falling from a height to the people on the ground floor.

[0038] Regarding the impact dispersion performance of the polyurethane layer, the honeycomb pore structure inside can not only enhance the lightweight characteristics of the material but also further improve its impact energy absorption effect. The micron-sized pores can absorb part of the impact energy through the compression effect when being impacted and reduce local stress concentration when the glass breaks.

[0039] During the preparation process, the Fe 3 O 4 particles in the polyurethane layer are placed in a magnetic field, causing the Fe 3 O 4 particles to align along the magnetic induction line direction, and at the same time driving the nano-cellulose whiskers to align directionally to form a grid-like structure, which improves the mechanical properties of the polyurethane layer, mainly reflected in: The grid structure improves the toughness of the material: The directionally aligned nano-cellulose whiskers and Fe 3 O 4 particles form a grid structure with enhanced mechanical properties. During impact, this structure can effectively disperse the external force and conduct energy through the chain-like paths between the nano-cellulose and Fe 3 O 4 particles, thereby reducing stress concentration; Prevent crack propagation: The grid structure has high toughness and can effectively prevent crack propagation. When micro-cracks occur in the glass, the grid structure will play a restraining role, restricting the cracks from spreading to a wider area and preventing large-area fragment scattering when the glass breaks.

[0040] It should be noted that the amphiphilic block copolymer added to the polyurethane layer can self-assemble to form a three-dimensional interpenetrating network structure at the gas-liquid interface, and its specific manifestation in improving the impact dispersion performance is as follows: Relieve local stress concentration: The three-dimensional network structure can distribute energy when subjected to stress to avoid stress concentration. Each node and channel in the structure can effectively disperse the impact force to prevent excessive stress concentration in local areas of the glass, which may lead to cracking. Multi-level energy dissipation: The three-dimensional interpenetrating network structure has a multi-level energy dissipation effect. When impacted, the external force is first relieved through the honeycomb structure and grid structure of the polyurethane layer, and then further dispersed in the three-dimensional network structure, thereby gradually reducing the intensity of the impact force. The multi-level energy dissipation mechanism enables the polyurethane layer to effectively reduce the transmission of impact force, thereby protecting the glass layer from brittle fracture.

[0041] In summary, the polyurethane layer forms a multi-level impact dispersion and absorption mechanism through the honeycomb pores, magnetic field induced grids, three-dimensional interpenetrating networks and reinforcing materials nanocellulose whiskers and Fe3O4 particles. Through the coordinated work of these mechanisms, the polyurethane layer can effectively absorb and disperse external impact energy, reduce the direct effect of impact on the glass; prevent fragments from flying when the glass breaks, maintain the integrity of the glass; and improve the impact resistance of the glass so that it will not suffer brittle fracture when encountering impact.

[0042] In the present invention, in step S4, a polyurethane layer is placed between a first layer of glass and a second layer of glass, and laminated glass is prepared by vacuum hot pressing; In the process of preparing laminated glass by vacuum hot pressing, after the preparation of the polyurethane layer is completed, it serves as the core layer in the laminated glass to provide additional impact resistance, anti-shattering and impact relief functions, and integrates the first layer of glass, the polyurethane layer and the second layer of glass into a three-layer structure. At this time, the polyurethane layer serves as an intermediate layer to completely separate the first layer of glass from the second layer of glass, and the contact surface of the two layers of glass needs to be tightly and evenly covered with the polyurethane layer.

[0043] In a vacuum environment, the three-layer structure of the laminated glass (including the polyurethane layer) will be heated to between 80-120°C. During this process, the polyurethane layer will be heated to a softened state to facilitate better bonding with the glass layer; During the heating process, vacuum is required to remove bubbles and impurities in the laminated glass structure to ensure close contact between the layers without gaps. The vacuum environment helps to improve the pressing quality, avoid air residue or bubble formation, and avoid affecting the transparency and resistance of the glass layer.

[0044] When the polyurethane layer reaches a certain softening state, pressure is applied to ensure that the first layer of glass, the polyurethane layer and the second layer of glass are more tightly bonded, thereby avoiding gaps or local poor contact.

[0045] After the vacuum hot pressing is completed, the temperature is gradually lowered to allow the polyurethane layer to harden again, solidify and maintain its structural properties. At this time, the first layer of glass, the polyurethane layer and the second layer of glass have been firmly combined together to form a stable laminated glass.

[0046] During this vacuum hot pressing process, the polyurethane layer is in full contact with the glass surface in a softened state. Through the effects of vacuum and hot pressing, a strong adhesion force can be formed between the polyurethane layer and the glass layer to avoid separation or falling off between the layers. Vacuum hot pressing can also ensure that the contact surface between the polyurethane layer and the two layers of glass is smooth and uniform without bubbles, cracks or unevenness, making the overall structure of the glass stable and greatly improving the impact resistance.

[0047] Among them, the polyurethane layer, as the core layer of the laminated glass, can effectively absorb and disperse external impacts. The vacuum hot pressing ensures the close bonding between the polyurethane layer and the glass layer, which enhances the energy dispersion and absorption capacity of the polyurethane layer when it is impacted, thereby improving the impact resistance of the laminated glass. Due to the energy absorption and dispersion of the polyurethane layer, even if the glass is subjected to severe impact, it can prevent the glass from brittle fracture or fragments from flying.

[0048] In summary, the present invention can effectively prevent glass from bursting by preparing a laminated glass with bidirectional breaking characteristics. When the laminated glass is used on the curtain wall of a high-rise building, the first layer of glass is facing the inside of the high-rise building, and the second layer of glass is facing the outside of the building. Due to the uniform and stable stress distribution formed in the ion exchange of the first layer of glass, the anti-burst performance of the first layer of glass is improved, and the polyurethane layer bonded to the first layer of glass has a high-efficiency impact dispersion performance. After the first layer of glass is directly impacted, the impact force can be further dispersed by the polyurethane layer, thereby ensuring the safety of people in the building. If the first layer of glass is broken by a greater impact force, the glass can be broken locally instead of being broken as a whole due to the adhesion of the polyurethane, thereby ensuring that the glass inside the high-rise building is broken after being impacted. The adhesion of the polyurethane layer can make the glass as a whole still intact, effectively maintaining the adhesion of glass fragments, preventing the fragments from flying, and preventing the fragments from falling from a high altitude from causing harm to people on the bottom. When a fire or other dangerous situation occurs in a high-rise building and high-altitude rescue is required, it is necessary to impact the second-layer glass so that the entire laminated glass is shattered and the fragments are dispersed. Therefore, an asymmetric prestress distribution and stress concentration design are introduced in the preparation of the second-layer glass to form a stress gradient structure. When subjected to an external impact, the prestress distribution can transfer the external force inward and concentrate it at specific stress concentration points of the glass, inducing a strong local stress concentration effect when the glass breaks. This breaking point will further transmit stress in the direction of the impact, triggering a larger range of glass breakage, effectively enhancing the overall destructive force, driving the entire laminated glass to break and causing the glass fragments to fall off, thus ensuring the smooth opening of the rescue passage. At the same time, the impact direction of the glass fragments is controlled to avoid danger caused by the high-altitude fall of the fragments.

[0049] Example 1:

[0050] I. Experimental Preparation Experimental Group 1: Select 100 parts by weight of quartz sand, 20 parts of sodium oxide, 15 parts of calcium oxide, 12 parts of potassium carbonate, and 5.5 parts of aluminum oxide, mix them evenly, and melt them at 1600 °C for 6 h to obtain a liquid glass matrix; Pour the liquid glass matrix into a forming mold, flatten it by gravity to form a flat glass, immerse side A of the flat glass in a KNO3 molten salt bath with a mass ratio of 95:3 between KNO3 and NaNO3 at 480 °C for 8 h to form a 70 ± 2 μm deep high-potassium ion concentration gradient, immerse side B of the flat glass in a KNO3 molten salt bath with a mass ratio of 95:3 between KNO3 and NaNO3 at 380 °C for 2.5 h to form an 18 ± 2 μm shallow and uniform potassium ion penetration layer. Place the center of side A of the flat glass after ion exchange at the preset stress concentration point, and cool side A of the flat glass by high-speed nitrogen injection with a wind speed of 30 m / s and a cooling rate of 120 °C / s, and cool side B by natural convection with a cooling rate of 50 °C / s to form an asymmetric stress distribution layer, obtaining a second-layer glass with a thickness of 6 mm.

[0051] Experimental Group 2: Select 100 parts by weight of quartz sand, 20 parts of sodium oxide, 15 parts of calcium oxide, 12 parts of potassium carbonate, and 5.5 parts of aluminum oxide, mix them evenly, and melt them at 1600 °C for 6 h to obtain a liquid glass matrix; Pour the liquid glass matrix into a forming mold, flatten it by gravity to form a flat glass, immerse both sides A and B of the flat glass in a KNO3 molten salt bath at 480 °C for 8 h to form a 70 μm ± 2 deep high-potassium ion concentration gradient, and cool side A of the flat glass by high-speed nitrogen injection with a wind speed of 30 m / s and a cooling rate of 120 °C / s, and cool side B by natural convection with a cooling rate of 50 °C / s to form an asymmetric stress distribution layer, obtaining a second-layer glass with a thickness of 6 mm.

[0052] Experimental Group 3: Select 100 parts by weight of quartz sand, 20 parts of sodium oxide, 15 parts of calcium oxide, 12 parts of potassium carbonate, and 5.5 parts of aluminum oxide, mix them evenly, and melt them at 1600 °C for 6 h to obtain a liquid glass matrix; Pour the liquid glass matrix into a forming mold, and form a flat glass by gravity spreading. Immerse both sides A and B of the flat glass into a KNO3 molten salt bath with a mass ratio of 95:3 between KNO3 and NaNO3 at 380 °C for 2.5 h to form a shallow and uniform potassium ion penetration layer of 18 ± 2 μm. Then, cool the A side of the flat glass by high-speed nitrogen injection with a wind speed of 30 m / s and a cooling rate of 120 °C / s, and cool the B side by natural convection with a cooling rate of 50 °C / s to form an asymmetric stress distribution layer, obtaining the second layer of glass with a thickness of 6 mm.

[0053] II. Quantitative Test of Fragment Impact Force 1. Preparation of Experimental Equipment Drop Ball Impact Machine: Equipped with a 227 g ± 1 g quenched steel ball (HRC60 - 62); Height Adjustment Range: 0.5 - 6 m (accuracy ±0.1 cm); Ballistic Gelatin: 10% concentration (density 1.04 g / cm 3 , simulating human soft tissue); Standard Aluminum Plate: 2024 - T3 aluminum alloy, thickness 2 mm (simulating a rigid surface); High - speed Camera: Phantom V2512 (1280×800@100,000 fps); Dynamic Pressure Sensor: PCB 113B21 (range 0 - 50 MPa, response time 1 μs); Three - dimensional Laser Velocimeter: Dantec Dynamics BSA P60.

[0054] 2. Performance Test Steps Fix the glass samples (300×300×5 mm) of Experimental Group 1, Experimental Group 2, and Experimental Group 3 in special fixtures respectively, ensuring that the free margin around is ≥15 mm, and spray titanium dioxide speckles (diameter 50 μm, for Digital Image Correlation Method DIC analysis) on the sample surface; The release height of the steel ball is 4 m, corresponding to an impact energy of 98 J. Locate the geometric center of the sample through a laser crosshair (error < ±1 mm); Pour a 10% gelatin solution into a 40×40×40 cm mold, cure it at a constant temperature of 25 °C for 24 hours to obtain gelatin with a surface hardness of Bloom 250 ± 5, and embed a pressure sensor array in the gelatin in a grid pattern with a spacing of 50 mm. Attach strain gauges (range ±5000 με, sampling rate 1 MHz) to the surface of the aluminum plate.

[0055] The samples on both sides of A and B in the above Experimental Group 1, Experimental Group 2, and Experimental Group 3 were tested, and experimental data were obtained, as shown in Table 1.

[0056] Table 1:

[0057] Based on Table 1, it can be concluded that the second-layer glass prepared by the present invention has high impact resistance and thus high explosion-proof performance. After being impacted and broken on the A side, the impact force of the glass fragments generated by the breakage is the largest and concentrated and dispersed toward the B side.

[0058] Example 2: Energy Absorption and Fragment Adhesion of Polyurethane Interlayer I. Experimental Preparation Experimental Group 4: A. Select 100 parts by weight of quartz sand, 20 parts of sodium oxide, 15 parts of calcium oxide, 12 parts of potassium carbonate, and 5.5 parts of aluminum oxide, mix them evenly, and melt them at 1600 °C for 6 h to obtain a liquid glass matrix; B. Divide the liquid glass matrix into two parts. Pour one part of the liquid glass matrix into a forming mold, flatten it by gravity to form a flat glass, cool it at a rate of 3 °C / min to 350 °C, and immerse it in a KNO3 molten salt bath with a mass ratio of KNO3 to NaNO3 of 95:3 at 450 °C for 8 h for ion exchange, and then cool it to room temperature at a rate of 10 °C / min to obtain the first-layer glass; C. Pour the other part of the liquid glass matrix into a forming mold, flatten it by gravity to form a flat glass. Immerse the A side of the flat glass in a KNO3 molten salt bath with a mass ratio of KNO3 to NaNO3 of 95:3 at 480 °C for 8 h to form a 70 ± 2 μm deep high potassium ion concentration gradient. Immerse the B side of the flat glass in a KNO3 molten salt bath with a mass ratio of KNO3 to NaNO3 of 95:3 at 380 °C for 2.5 h to form an 18 ± 2 μm shallow uniform potassium ion permeation layer. Place the center of the A side of the flat glass after ion exchange at a preset stress concentration point, and spray and cool the A side of the flat glass with high-speed nitrogen at a wind speed of 30 m / s and a cooling rate of 120 °C / s, and cool the B side by natural convection at a cooling rate of 50 °C / s to form an asymmetric stress distribution layer to obtain the second-layer glass with a thickness of 6 mm; D. Mix polyether polyol and isocyanate in a mass ratio of 1:1.5 and react at 65 °C to generate a polyurethane prepolymer containing dynamic bonds. Add an amphiphilic block copolymer, nanocrystalline cellulose whiskers, and Fe 3 O 4Particles were mixed at a rotational speed of 2000 rpm for 35 min to obtain a mixed slurry. The mixed slurry was injected into a mold and placed in a uniform magnetic field of 0.8 T to drive the Fe 3 O 4 particles to align along the magnetic induction lines, driving the nanocellulose whiskers to form a grid-like structure. Azodicarbonamide was added and the temperature was raised to 85 °C to generate honeycomb pores, inducing the self-assembly of amphiphilic copolymers at the gas-liquid interface to form a three-dimensional interpenetrating network, forming an impact dispersion layer. The ultraviolet intensity was regulated in different regions, cured at 125 °C for 1.5 h, and annealed for 24 h to obtain a polyurethane layer with a thickness of 0.76 mm; E. With the polyurethane layer as the intermediate layer, the first layer of glass and the second layer of glass were respectively attached to both sides of the polyurethane layer. In a vacuum environment, it was heated to 80 - 120 °C to prepare laminated glass.

[0059] Experimental Group Five: It was substantially the same as Experimental Group Four, except that the intermediate layer used a 0.76 mm PVB film sourced from Beijing Haiyang Shunda Glass Co., Ltd.

[0060] 2. Test methods: The notched impact test was carried out according to the ASTM D256 standard to measure the energy absorption density; the fragment retention rate was tested according to ANSI Z97.1; The surface morphology of the intermediate film after impact was recorded, the boundary of the complete area was marked, and the proportion of the remaining area was calculated: retention rate = (complete area / total intermediate film area) × 100%; The intermediate film was broken by a standard hook claw or a pair of needle-nose pliers, and the time from applying force to complete tearing was recorded; as shown in Table 2.

[0061] Table 2:

[0062] In summary, the polyurethane layer prepared by the present invention has high-efficient impact dispersion performance and adhesiveness. The main reason is that during the preparation process, under the induction of the magnetic field, the Fe 3 O 4 particles drive the nanocellulose whiskers to be oriented along the direction of the magnetic induction lines, thereby forming a grid-like structure inside the material. When impacted, it can quickly disperse the external force, conduct the impact energy along the chain-like path between the nanofibers and the Fe 3 O 4 particles, effectively reducing the local stress concentration, thereby enhancing the overall impact dispersion performance. At the same time, by introducing azodicarbonamide foaming agent, micron-sized honeycomb pores are generated during the heating and foaming stage, enabling the amphiphilic block copolymer to self-assemble at the gas-liquid interface to form a three-dimensional interpenetrating network, firmly locking the glass fragments when the glass breaks, endowing the polyurethane layer with strong adhesion ability, and effectively preventing the fragments from falling off; Moreover, the laminated glass prepared by the present invention has the characteristic of bidirectional fragmentation and is suitable for high-altitude operations.

[0063] Based on the ideal embodiments of the present invention as inspiration, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing explosion-proof glass, characterized in that: The following steps are involved: Step S1, mixing silicon dioxide, sodium oxide, calcium oxide, aluminum oxide and potassium carbonate in proportion and heating them until they are molten to obtain a liquid glass matrix; Step S2, dividing the liquid glass matrix into two parts, and performing molding treatment on one part of the liquid glass matrix to obtain a first layer of glass; Step S3, applying directional stress to another portion of liquid glass substrate to form a stress concentration layer to obtain a second layer of glass; Step S4, taking polyether polyol and isocyanate to synthesize a polyurethane prepolymer, and subjecting it to magnetic field oriented arrangement, foaming self-assembly and gradient curing process to form a polyurethane layer with a honeycomb-grid interpenetrating structure as an impact dispersion layer, and using the polyurethane layer to press the first layer of glass and the second layer of glass to prepare laminated glass.

2. The method for preparing explosion-proof glass according to claim 1, characterized in that: In the step S1, glass substrate raw materials are selected, and the weight proportions thereof are 100 parts of quartz sand, 15-20 parts of sodium oxide, 10-15 parts of calcium oxide, 5-12 parts of potassium carbonate, and 1.5-5.5 parts of aluminum oxide.

3. The method for preparing explosion-proof glass according to claim 2, characterized in that: In the step S1, 0.1-0.2 parts of sodium nitrate and 0.5-1 parts of carbon powder are added to the glass substrate raw material and mixed evenly, and melted at 1550-1600° C. for 4-6 hours to obtain a liquid glass matrix.

4. The method for preparing explosion-proof glass according to claim 1, characterized in that: In step S2, the molding process includes the following steps: Step S21, introducing the liquid glass matrix into a forming mold, and flattening it by gravity to form a flat glass; Step S22, cooling the flat glass to 300°C-350°C at a rate of 3°C / min; Step S23, immersing the flat glass in a KNO3 molten salt bath at 400°C-450°C for 6-8h to perform ion exchange; Step S24, cooling the flat glass after ion exchange to room temperature at a rate of 10°C / min, and ultrasonically cleaning with deionized water to remove surface salt residues to obtain a first layer of glass.

5. The method for preparing explosion-proof glass according to claim 4, characterized in that: In the step S23, the KNO3 molten salt composition includes: KNO3 and NaNO3; and the mass ratio between KNO3 and NaNO3 is 95-97:3-5.

6. The method for preparing explosion-proof glass according to claim 1, characterized in that: In the step S3, the following sub-steps are included: Step S31, introducing the liquid glass matrix into a forming mold, and flattening it by gravity to form a flat glass; Step S32, immersing side A of the flat glass in a KNO3 molten salt bath at 450°C-480°C for 6-8 hours to form a 65-80 μm deep high potassium ion concentration gradient; Step S33, immersing the side B of the flat glass in a KNO3 molten salt bath having a mass ratio of KNO3 to NaNO3 of 95:3 at 350°C-380°C for 2-2.5 hours to form a 15-20 μm shallow and uniform potassium ion penetration layer; Step S34, positioning the center of side A of the flat glass after ion exchange at a preset stress concentration point; Step S35, cooling the side A of the flat glass that has completed step S34 by high-speed nitrogen jet at a wind speed of 25-30m / s and a cooling rate of 100-120℃ / s, and cooling the side B by natural convection at a cooling rate of 40-50℃ / s to form an asymmetric stress distribution layer to obtain a second layer of glass.

7. The method for preparing explosion-proof glass according to claim 6, characterized in that: In step S34, the setting of the stress concentration point includes: etching an array of micropores in the central area of ​​side A of the flat glass with a femtosecond laser of 1030 nm wavelength, wherein each micropore is a conical structure with a diameter of 45-50 μm and a depth of 95-100 μm, and is evenly arranged in a hexagonal symmetrical distribution pattern, with a center spacing of 480-500 μm between adjacent micropores.

8. The method for preparing explosion-proof glass according to claim 1, characterized in that: In step S4, the polyurethane layer is prepared, comprising the following steps: Step S41, polyether polyol and isocyanate are mixed in a mass ratio of 1-2:1.5-4, and reacted at 50-65° C. to generate a polyurethane prepolymer containing dynamic bonds; Step S42, adding the amphiphilic block copolymer, nanocellulose whiskers and Fe3O4 particles to the polyurethane prepolymer, mixing at a rotation speed of 2000 rpm for 30-35 minutes to obtain a mixed slurry; Step S43, injecting the mixed slurry into a mold, placing it in a 0.5-0.8T uniform magnetic field, driving the Fe3O4 particles to align along the magnetic flux lines, driving the nanocellulose whiskers to form a grid-like structure; Step S44, adding azodicarbonamide and raising the temperature to 75-85° C. to generate honeycomb holes, inducing the amphiphilic copolymer to self-assemble at the gas-liquid interface to form a three-dimensional interpenetrating network and an impact dispersion layer; Step S45, adjusting the ultraviolet intensity by region, curing at 110-125° C. for 1.5-2 h, and annealing for 24 h to obtain a polyurethane layer.

9. The method for preparing explosion-proof glass according to claim 1, characterized in that: The thickness of the first layer of glass is 5.8-6.2 mm, the thickness of the second layer of glass is 5.8-6.2 mm, and the thickness of the polyurethane layer is 0.7-1.2 mm.

10. The method for preparing explosion-proof glass according to claim 1, characterized in that: In the step S4, a polyurethane layer is placed between the first layer of glass and the second layer of glass, and laminated glass is prepared by vacuum hot pressing.

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