Crack-arrest ballistic-resistant glass and methods of making and using the same

Abstract

The application provides a crack-blocking bulletproof glass and a preparation method and application thereof. The bulletproof glass comprises a back layer, a bonding layer and an impact surface layer arranged in sequence; the back layer and the impact surface layer are made of polycarbonate material; the bonding layer is a laminated adhesive film structure integrally formed by a plurality of inorganic glass polyurethane composite layers; the inorganic glass polyurethane composite layer is composed of discrete distributed sheet-shaped inorganic glass units and polyurethane adhesive material; the sheet-shaped inorganic glass units are arranged in a spaced paving mode, the distance between adjacent sheet-shaped inorganic glass units is 1-2 mm, and the polyurethane adhesive material is filled in the surface of the sheet-shaped inorganic glass units and the gap between adjacent units; the sheet-shaped inorganic glass units are arranged in a staggered mode, and the staggered direction is parallel to the arrangement plane. The technical problem to be solved is how to design and prepare a crack-blocking bulletproof glass with a simple structure and easy mass production, so that the crack propagation is blocked from the root, and the bulletproof performance is ensured while the clear vision is maintained.

Description

Technical Field

[0001] This invention relates to the field of glass manufacturing technology, and in particular to a crack-blocking bulletproof glass, its preparation method, and its application. Background Technology

[0002] Bulletproof glass, as a special protective material, is widely used in finance, security, transportation, and other fields. Its core function is to withstand bullet fire or other impact attacks, ensuring the safety of personnel and important property. Existing bulletproof glass typically employs a multi-layered composite structure, mainly including high-strength inorganic glass, polymethyl methacrylate (PMMA), and organic film components. Its protective principle is as follows: when a bullet hits, the inorganic glass breaks first to dissipate some of the impact energy. The middle organic film layer, with its high toughness, absorbs a large amount of energy and adheres glass fragments, preventing secondary injury. The inner glass layer further blocks remaining fragments and dissipates residual energy. High-strength inorganic glass, due to its high hardness and strength, can blunt, damage, or even shatter projectiles, altering the bullet's structure to reduce penetration. It is a crucial load-bearing and initial energy absorption component in the bulletproof system. However, the inherent brittleness of inorganic glass causes irregular radial cracks to form at the point of impact after being hit by a bullet. These cracks extend widely and can easily form cracks across the entire glass surface, severely affecting the visibility of the bulletproof glass and causing significant inconvenience for subsequent observation, operation, or escape.

[0003] In existing technologies, some solutions improve impact resistance by increasing the thickness of the glass. While this can improve impact resistance, it increases the product's weight and production costs, and cannot fundamentally solve the problem of crack propagation. Other solutions design complex cross structures and spiral structures to induce crack deflection, but these designs are complex, difficult to manufacture, and the cracks still have the risk of propagation, failing to limit the fracture range at its source. Summary of the Invention

[0004] The main objective of this invention is to provide a crack-blocking bulletproof glass, its preparation method, and its application. The technical problem to be solved is how to design and prepare a crack-blocking bulletproof glass with a simple structure that is easy to mass-produce, so as to prevent crack propagation from the source, maintain clear vision while ensuring bulletproof performance, and thus be more suitable for practical use.

[0005] The objective of this invention and the technical problem it solves are achieved through the following technical solution. A crack-blocking bulletproof glass according to this invention comprises: The back layer is made of polycarbonate. An adhesive layer is disposed on the surface of the back layer; the adhesive layer is a multi-layered inorganic glass polyurethane composite layer integrally formed laminated film structure; the inorganic glass polyurethane composite layer is composed of discretely distributed sheet-like inorganic glass units and polyurethane adhesive material; in each layer of the inorganic glass polyurethane composite layer, the sheet-like inorganic glass units are arranged in a spaced-apart, flat manner, with a spacing of 1~2mm between adjacent sheet-like inorganic glass units, and the polyurethane adhesive material fills the surface of the sheet-like inorganic glass units and the gaps between adjacent units; the sheet-like inorganic glass units in adjacent layers of the inorganic glass polyurethane composite layer are arranged in a staggered manner, and the staggered direction is parallel to the arrangement plane; the polyurethane adhesive material has an elongation at break ≥400%, tensile strength ≥28MPa, and light transmittance ≥90%; The impact surface layer, made of polycarbonate, is disposed on the surface of the adhesive layer away from the back layer; the back layer, adhesive layer, and impact surface layer are bonded together as an integral structure by the polyurethane adhesive material through a high-temperature hot-pressing process.

[0006] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0007] Preferably, in the crack-blocking bulletproof glass, the sheet-like inorganic glass unit is a square structure with a side length of 20-60mm, and the square inorganic glass units in adjacent inorganic glass polyurethane composite layers are staggered along the diagonal; the adhesive layer is an N-layer stacked inorganic glass polyurethane composite layer, where N is an integer ≥3; the misalignment dimension between adjacent inorganic glass polyurethane composite layers is... When N > 3, the arrangement positions of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers are the same as the arrangement positions of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥ 1.

[0008] Preferably, in the crack-blocking bulletproof glass, the sheet-like inorganic glass unit is a regular hexagonal structure with a side length of 10~40mm, and the regular hexagonal inorganic glass units in adjacent layers of the inorganic glass polyurethane composite layer are translated and misaligned along the interlayer; the adhesive layer is an N-layer inorganic glass polyurethane composite layer, where N is an integer ≥3; the side length of the sheet-like inorganic glass unit is d3, and the distance between adjacent sheet-like inorganic glass units is d4; taking the first layer as a reference, the second layer is translated d3+d4 distance along the first side length direction of the regular hexagon; the third layer is translated d3+d4 distance along the second side length direction of the regular hexagon; the first side length and the second side length are adjacent side lengths; when N>3, the arrangement position of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers is the same as the arrangement position of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥1.

[0009] Preferably, in the crack-blocking bulletproof glass, the thickness of the impact surface layer is 2-8 mm, and the thickness of the back layer is 20-40 mm.

[0010] Preferably, in the crack-blocking bulletproof glass, the thickness of the sheet-like inorganic glass unit is 1~3mm, and the thickness of the interlayer adhesive layer is 0.2~1mm.

[0011] The objective of this invention and the technical problem it solves are achieved through the following technical solution. A method for preparing crack-blocking bulletproof glass according to this invention includes the following steps: S1 processes inorganic glass into discretely distributed sheet-like inorganic glass units; the sheet-like inorganic glass units have a planar structure; S2. The sheet-like inorganic glass unit is immersed in a polyurethane solution and then degassed under vacuum. The polyurethane adhesive material formed after the polyurethane solution is cured has an elongation at break ≥400%, a tensile strength ≥28MPa, and a light transmittance ≥90%. S3 involves arranging sheet-like inorganic glass units with polyurethane solution adhering to them in a flat, spaced manner on the surface of polycarbonate material. The spacing between adjacent sheet-like inorganic glass units is controlled to be 1-2 mm, forming the first inorganic glass polyurethane composite layer. S4 On the first inorganic glass polyurethane composite layer, continue to lay and arrange sheet-like inorganic glass units with polyurethane solution adhering to them, so that the sheet-like inorganic glass units of adjacent layers are staggered and the staggered direction is parallel to the arrangement plane, forming a second and above inorganic glass polyurethane composite layer. S5 covers the surface of the last inorganic glass polyurethane composite layer with polycarbonate material, and places the whole in a vacuum bag for vacuuming and high-temperature hot pressing treatment to cure the multi-layer inorganic glass polyurethane composite layer, forming an integrally molded laminated film structure, which is tightly bonded to the polycarbonate material on both sides to obtain crack-blocking bulletproof glass; the high-temperature hot pressing temperature is 110±10℃ and the pressure is 1.2±0.2MPa.

[0012] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0013] Preferably, in the preparation method, the sheet-like inorganic glass unit is processed into a square structure with a side length of 20-60 mm; adjacent layers of sheet-like inorganic glass units are staggered along the diagonal direction; the laminated film structure includes N layers of stacked inorganic glass polyurethane composite layers, where N is an integer ≥ 3; the side length of the sheet-like inorganic glass unit is d1, and the spacing between adjacent sheet-like inorganic glass units is d2; the staggered size between adjacent layers is... When N > 3, the arrangement positions of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers are the same as the arrangement positions of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥ 1.

[0014] Preferably, in the preparation method, the sheet-like inorganic glass unit is processed into a regular hexagonal structure with a side length of 10~40mm; adjacent layers of sheet-like inorganic glass units are translated and staggered along the interlayer; the laminated film structure is an inorganic glass polyurethane composite layer stacked with N layers, where N is an integer ≥3; the side length of the sheet-like inorganic glass unit is d3, and the spacing between adjacent sheet-like inorganic glass units is d4; taking the first layer as a reference, the second layer is translated d3+d4 distance along the first side length direction of the regular hexagon; the third layer is translated d3+d4 distance along the second side length direction of the regular hexagon; the first side length and the second side length are adjacent side lengths; when N>3, the arrangement positions of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers are the same as the arrangement positions of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥1.

[0015] Preferably, in the preparation method, the polyurethane solution is prepared by mixing isocyanate, polyester polyol, polyether polyol, small molecule polyol and catalyst.

[0016] The objective of this invention and the technical problem it solves are achieved through the following technical solution. According to this invention, an application of the aforementioned crack-blocking bulletproof glass is proposed in protective scenarios where both bulletproof performance and visibility need to be maintained.

[0017] By employing the above technical solution, the crack-blocking bulletproof glass, its preparation method, and its application proposed in this invention have at least the following beneficial effects: The crack-blocking bulletproof glass, its preparation method, and its application proposed in this invention achieve multiple technical advantages through deep synergy between product structure, manufacturing process, and application scenarios: In terms of product structure, it spatially cuts off the crack propagation path by using discretely distributed sheet-like inorganic glass units (as the core for bullet breakage prevention) with a 1-2mm interval design. Simultaneously, the staggered layout of adjacent layers parallel to the plane of arrangement ensures that only local units break after bullet impact, completely avoiding the problem of widespread cracking in traditional bulletproof glass. Double-sided polycarbonate layers provide stable support, while the polyurethane bonding material efficiently absorbs impact energy with an elongation at break of ≥400%, ensures strong interlayer bonding with a tensile strength of ≥28MPa, and maintains clear vision with ≥90% light transmittance. These three elements work synergistically to achieve bulletproof protection. This invention combines energy conservation, crack prevention, and visibility preservation. In terms of manufacturing process, it eliminates the need for complex structural molding equipment. Production can be completed simply through sheet unit processing, polyurethane impregnation and degassing, staggered layering, and standardized high-temperature hot pressing (110±10℃, 1.2±0.2MPa). The process is simple and controllable, adaptable to industrial mass production needs. Precise control of vacuum degassing and hot pressing parameters ensures the stability and consistency of performance for each batch. From an application perspective, the core advantage of this invention precisely matches the needs of scenarios requiring both bulletproof protection and unobstructed vision, such as financial security, transportation, and security facilities. Its simple structure and reliable performance allow it to flexibly adapt to installation and usage requirements in different scenarios, demonstrating significant practical value and promotional potential.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the crack-blocking bulletproof glass of the present invention; Figure 2 This is a schematic diagram of the stacked distribution structure of a square inorganic glass unit in one embodiment; Figure 3 This is a schematic diagram of the stacked distribution structure of a regular hexagonal inorganic glass unit in another embodiment. Detailed Implementation

[0020] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the appended tables and preferred embodiments, details the specific implementation methods and effects of a crack-blocking bulletproof glass, its preparation method, and its application according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, the results of one or more embodiments can be combined in any suitable manner. These embodiments are provided to make the invention thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​described in these embodiments should be interpreted as merely exemplary and not as limiting.

[0021] This invention proposes a crack-blocking bulletproof glass, as shown in the attached figure. Figure 1 To be continued Figure 3 As shown, it includes: Back layer 1 is made of polycarbonate material; Adhesive layer 2 is disposed on the surface of the back layer; this adhesive layer is a multi-layered inorganic glass polyurethane composite layer integrally formed laminated film structure; the inorganic glass polyurethane composite layer is composed of discretely distributed sheet-like inorganic glass units and polyurethane adhesive material; the core function of the discretely distributed sheet-like inorganic glass units is to prevent bullet breakage; in each layer of inorganic glass polyurethane composite layer, the sheet-like inorganic glass units are arranged in a spaced-out, flat manner, with a spacing of 1~2mm between adjacent sheet-like inorganic glass units, and the polyurethane adhesive material fills the surface of the sheet-like inorganic glass units and the gaps between adjacent units; the sheet-like inorganic glass units in adjacent layers of inorganic glass polyurethane composite layer are arranged in a staggered manner, and the staggered direction is parallel to the arrangement plane; the elongation at break of the polyurethane adhesive material is ≥400%, the tensile strength is ≥28MPa, and the light transmittance is ≥90%; Impact layer 3, made of polycarbonate, is placed on the surface of the adhesive layer away from the back layer; the back layer, adhesive layer and impact layer are bonded together as an integral structure by polyurethane adhesive through a high-temperature hot-pressing process.

[0022] The core design logic of the above technical solution is as follows: using discrete inorganic glass units as the core to block bullet breakage and the spaced layout to cut the physical path of crack propagation; using the interlayer staggered arrangement design to prevent cracks from spreading across layers; using high-performance polyurethane adhesive materials to balance energy absorption, interlayer bonding and light transmission; and using double-sided polycarbonate layers to provide structural support, the technical goal of the present invention is to achieve bulletproof glass that does not crack, does not spread if it cracks, and does not obstruct vision.

[0023] In the above technical solution, polycarbonate material is used as the back layer and impact surface layer. Taking advantage of its impact resistance strength being 250-300 times that of ordinary glass, its excellent toughness, and its weight being only half that of glass, it serves as a rigid support for the overall structure and can also help absorb residual energy during bullet impact, preventing itself from breaking. Its molecular chain has strong toughness and is not prone to brittle fracture when impacted, which can effectively disperse impact stress. At the same time, its lightweight characteristics make it well-suited for weight-sensitive scenarios such as financial security cabinets and bulletproof doors and windows.

[0024] In the above technical solution, the polyurethane adhesive used in the adhesive layer has an elongation at break of ≥400%, a tensile strength of ≥28MPa, and a light transmittance of ≥90%. A good balance of strength, toughness, and light transmittance is achieved through formulation adjustment. Isocyanate provides tensile strength (≥28MPa) as the hard segment, polyester polyol and polyether polyol provide elongation at break (≥400%) as the soft segment, small molecule polyols act as chain extenders to increase crosslinking density, and catalysts accelerate the curing reaction. The polyurethane has a two-phase structure of hard and soft segments. The hard segment ensures the strong adhesion between layers, while the soft segment absorbs a large amount of energy through elastic deformation when impacted by a bullet. At the same time, the high light transmittance (≥90%) ensures that the field of vision is not affected by the adhesive layer.

[0025] In some specific embodiments of the present invention, the sheet-like inorganic glass units are preferably square structures with a side length of 20-60 mm, and the spacing between adjacent units is 1-2 mm. The 20-60 mm side length design can fully utilize the high hardness of inorganic glass to effectively passivate, damage, or even shatter bullets, ensuring the core performance of ballistic protection. The 1-2 mm spacing can both spatially cut the crack propagation path, confining the crack to a single unit and preventing the formation of cracks across the entire surface, and avoid blind spots due to excessive spacing, ensuring that the ballistic protection efficiency does not decrease. The inherent brittle fracture characteristics of inorganic glass determine that the discretely distributed sheet-like units can prevent the continuous propagation of cracks, while the polyurethane bonding material filled in the spacing can absorb the energy required for crack propagation through elastic deformation, further preventing cracks from penetrating from one unit to adjacent units, ultimately achieving synergy in ballistic protection performance, crack blocking, and visibility preservation. If the side length of the sheet-like inorganic glass unit exceeds 60mm, the area of ​​a single unit is too large, and the fracture range of the unit will expand accordingly upon bullet impact, easily forming a local fracture zone with a diameter ≥50mm. Although it can still block the entire surface crack, it will affect the local field of vision. If the side length is less than 20mm, the hardness support of a single unit is insufficient, making it difficult to effectively passivate high-speed bullets, resulting in a decrease in bulletproof efficiency. Moreover, an excessive number of units will increase processing and arrangement costs. When the spacing is less than 1mm, the distance between adjacent units is too narrow, and the crack propagation energy can easily be transferred through the polyurethane adhesive material, failing to completely cut the crack path. When the spacing is greater than 2mm, a protection blind zone will be formed, and the bullet may penetrate through the gap, reducing the reliability of bulletproof protection. This invention, through precise matching of size and spacing, ensures that the effective protection range of each sheet-like inorganic glass unit (unit area + half of the adjacent spacing) uniformly covers the entire adhesive layer plane, eliminating protection blind zones and ensuring that after a single unit breaks, the crack is completely absorbed by the polyurethane material of the adjacent spacing, preventing it from spreading to surrounding units.

[0026] In some specific embodiments of the present invention, the adhesive layer is preferably an N-layer inorganic glass polyurethane composite layer, where N is an integer ≥ 3; the side length of the square sheet-like inorganic glass unit is d1, and the spacing between adjacent sheet-like inorganic glass units is d2; the misalignment dimension between adjacent layers of inorganic glass polyurethane composite layer is... When N > 3, the arrangement positions of the sheet-like inorganic glass units in layers 3n+1, 3n+2, and 3n+3 are the same as those in the first, second, and third layers, where n is an integer ≥ 1. This multi-layered structure can construct multiple protective barriers, repeatedly blunting and fragmenting the bullet. The staggered spacing between layers cuts the vertical propagation path of the cracks. The first composite layer blunts the bullet and initially dissipates its energy; the second and subsequent layers further attenuate the energy, preventing penetration. The staggered layout prevents cracks in the first-layer fragmentation units from extending to corresponding positions in the lower layers, achieving dual protection in both planar and vertical directions. The value of N can be adapted to different protection levels. In conventional scenarios, N = 3 is sufficient; in high-protection-level scenarios, N = 4~5, with consistent layer structures to suit industrial mass production.

[0027] In some specific embodiments of the present invention, the sheet-like inorganic glass unit is preferably a regular hexagonal structure with a side length of 10~40mm, and the regular hexagonal inorganic glass units in adjacent inorganic glass polyurethane composite layers are translated and misaligned along the interlayer; more preferably, the adhesive layer is an inorganic glass polyurethane composite layer with N layers stacked together, where N is an integer ≥3; the side length of the regular hexagonal sheet-like inorganic glass unit is d3, and the distance between adjacent sheet-like inorganic glass units is d4; taking the first layer as a reference, the second layer is translated d3+d4 distance along the first side length direction of the regular hexagon; the third layer is translated d3+d4 distance along the second side length direction of the regular hexagon; the first side length and the second side length are adjacent side lengths; when N>3, the arrangement position of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers is the same as the arrangement position of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥1.

[0028] In the above technical solution, the regular hexagonal units can achieve seamless close packing in a plane, with a planar coverage efficiency of 90.69%, reducing blind spots. The six sides of the regular hexagon are of equal length, and all interior angles are 120°. When a bullet impacts, the impact force can be evenly distributed along the six sides to the entire unit, avoiding the risk of localized cracking due to stress concentration. Furthermore, the smooth edges of the regular hexagon prevent sharp corners from scratching the polyurethane layer, improving structural stability. If the side length exceeds 40mm, the area of ​​a single unit becomes too large, and the rupture range of the unit will expand accordingly upon bullet impact, easily forming a localized rupture zone with a diameter ≥80mm. Although it can still block the overall crack, it will reduce the clarity of the local field of vision. At the same time, the increased weight of large-sized units may lead to an increase in the overall weight of the adhesive layer, affecting the product's lightweight advantage. If the side length is less than 10mm, the hardness support of a single unit is insufficient, making it difficult to effectively passivate high-speed bullets, resulting in a decrease in bulletproof efficiency. Moreover, the surge in the number of small-sized units will significantly increase the processing and arrangement costs and difficulty, which is not conducive to industrial mass production. The regular hexagonal structure can be flexibly adapted to curved and irregularly shaped protective surfaces, and can be fitted to curved surfaces without cutting. The close-packed planar design ensures consistent protection and is suitable for scenarios with high protection requirements.

[0029] In some specific embodiments of the present invention, the thickness of the impact surface layer is preferably 2-8 mm and the thickness of the back layer is 20-40 mm. Both are made of polycarbonate sheets by precision cutting. During preparation, the appropriate specifications can be flexibly selected within this thickness range according to the level requirements of the actual protection scenario. For example, a 2-4 mm impact surface layer and a 20-30 mm back layer are selected for basic protection scenarios, and a 5-8 mm impact surface layer and a 30-40 mm back layer are selected for high-level protection scenarios. The impact surface layer and back layer of the corresponding thickness are then used as the outer and inner layers of the bulletproof glass, respectively, and are bonded together with the middle adhesive layer through a high-temperature hot-pressing process to form a whole. As the outer layer directly facing bullet impact, the impact surface layer, with a thickness of 2-8mm, represents the optimal balance between the impact resistance and lightweight properties of polycarbonate. This thickness allows polycarbonate to effectively disperse impact stress, passivate the bullet, and initially absorb impact energy in the early stages of impact, thanks to its high impact resistance. This prevents the impact surface layer from being directly penetrated by the bullet or undergoing irreversible plastic deformation due to excessive thickness. Conversely, excessive thickness does not increase the overall weight of the product, negating the lightweight advantage of polycarbonate. The back layer, as the inner layer that provides final protection, is the last barrier against the bullet's residual energy and glass fragments. A thickness of 20-40mm fully utilizes the high toughness and resistance to brittle fracture of polycarbonate molecular chains, maximizing the absorption of residual energy dissipated by the bullet through the adhesive layer. This completely blocks fragment scattering and penetration, while providing stable rigid support for the entire bulletproof glass structure, preventing deformation and failure of the overall structure under impact. This thickness combination creates a gradient protection structure of "thin outer layer and thick inner layer," which works in synergy with the crack blocking and multi-layer energy absorption functions of the adhesive layer. The 2-8mm thin design of the impact surface layer effectively controls the overall weight of the product, making it suitable for protection scenarios with weight requirements, such as financial security and transportation. Meanwhile, the 20-40mm thick back layer provides high-level bulletproof protection, eliminating the risk of bullet or fragment penetration. Furthermore, the polycarbonate material maintains excellent light transmittance within this thickness range, combined with the adhesive layer's ≥90% light transmittance, ensuring clear and unobstructed vision from the bulletproof glass. Simultaneously, the polycarbonate sheets in this thickness range are of standard industrial specifications, requiring no special customization. They can be directly precision-cut and subsequently hot-pressed, meeting the process requirements of industrial mass production and effectively reducing production costs.

[0030] In some specific embodiments of the present invention, the thickness of the sheet-like inorganic glass unit is preferably 1-3 mm, and the thickness of the interlayer adhesive layer is 0.2-1 mm. The technical purpose of this design is that the 1-3mm thickness of the inorganic glass sheet retains the core characteristics of high hardness and high compressive strength of inorganic glass, which can effectively passivate, damage, or even shatter high-speed projectiles, playing a key role in bullet fragmentation and blocking. At the same time, it avoids the problems of increased product weight, increased processing difficulty, and excessively large fracture range after impact caused by thick glass sheets. The brittle fracture of thin sheets is more easily confined to local units. The 0.2-1mm thickness of the interlayer adhesive layer is the optimal range that balances adhesion performance, energy absorption, and light transmittance. This thickness ensures that the polyurethane adhesive can fully adhere to the surface of the inorganic glass sheet. With its ≥400% elongation at break and ≥28MPa tensile strength, it can absorb crack propagation energy through elastic deformation during impact, preventing crack propagation across units and layers. It also avoids the problem of interlayer stress concentration and reduced overall light transmittance caused by excessively thick adhesive layers, and the problem of interlayer delamination caused by excessively thin adhesive layers. This thickness combination achieves a deep synergy between the ballistic performance of the inorganic glass sheet and the crack-blocking and interlayer bonding functions of the polyurethane adhesive layer. The 1-3mm inorganic glass sheet limits the breakage after a bullet impact to a local unit, while the 0.2-1mm adhesive layer further cuts off the physical path of crack propagation, completely avoiding the problem of cracks across the entire surface of traditional bulletproof glass. At the same time, the precise control of the adhesive layer thickness ensures that the overall light transmittance is ≥90%, achieving a three-in-one effect of ballistic performance, crack blocking, and visibility preservation.

[0031] This invention also proposes a method for preparing crack-blocking bulletproof glass, comprising the following steps: First, the sheet-like inorganic glass units are processed into a planar structure. Specifically, high-strength inorganic glass is processed into discretely distributed sheet-like inorganic glass units using a precision cutting machine. After cutting, the edges are polished with a diamond grinding wheel to remove burrs, preventing sharp burrs from scratching the polyurethane layer or causing localized stress concentration. This ensures a tight fit between the unit and the adhesive material, improves the overall structural integrity, and prevents interlayer delamination during impact. In some specific embodiments of this invention, the inorganic glass is preferably borosilicate glass with a hardness of HRC≥60 to ensure bullet passivation.

[0032] Next comes polyurethane impregnation and vacuum degassing; specifically, the sheet-like inorganic glass unit is completely immersed in the above polyurethane solution for a certain period of time, preferably more than 10 minutes, to ensure that the surface and edges of the unit are completely covered by the solution; then it is placed in a vacuum chamber and degassed for a certain period of time under a vacuum degree ≥ -0.09MPa, preferably more than 25 minutes, to completely remove the air bubbles in the polyurethane solution and avoid affecting the adhesion density, energy absorption efficiency and light transmittance.

[0033] Next is the staggered arrangement of sheet-like inorganic glass units; specifically, sheet-like inorganic glass units with polyurethane solution adhering to them are laid flat on the surface of polycarbonate material at intervals, with the spacing between adjacent sheet-like inorganic glass units controlled at 1~2mm, forming the first inorganic glass polyurethane composite layer; on the first inorganic glass polyurethane composite layer, sheet-like inorganic glass units with polyurethane solution adhering to them are continued to be laid flat, so that the sheet-like inorganic glass units of adjacent layers are staggered, and the staggered direction is parallel to the arrangement plane, forming the second and above inorganic glass polyurethane composite layers; ensuring that there is no projection overlap between adjacent layers, avoiding cross-layer crack propagation, and realizing that local cracking does not affect the overall field of vision.

[0034] Finally, vacuum hot-press curing is performed. Specifically, polycarbonate material is covered on the surface of the last inorganic glass polyurethane composite layer. The entire layer is placed in a vacuum bag, vacuumed, and maintained for a certain period of time to remove interlayer air and prevent delamination. Then, the vacuum bag is placed in an autoclave and hot-pressed at 110±10℃ and 1.2±0.2MPa for a certain period of time, followed by natural cooling to room temperature. This temperature is the optimal curing temperature for the polyurethane system. Curing is incomplete below 100℃, and thermal deformation of the PC layer occurs above 120℃. This pressure forces the polyurethane to fill all gaps, forming a dense bond, ensuring the overall structure is integrated, meets impact resistance standards, and maintains good flatness and light transmittance.

[0035] In some specific embodiments of the present invention, the polyurethane solution is preferably prepared by mixing isocyanate, polyester polyol, polyether polyol, small molecule polyol and catalyst, and the comprehensive balance of strength, toughness and light transmittance is achieved by adjusting the formula.

[0036] The present invention also proposes an application of the aforementioned crack-blocking bulletproof glass in protective scenarios where both bulletproof performance and visibility need to be maintained.

[0037] In practical applications, inorganic glass materials with suitable cost-effectiveness can be selected for the manufacture of crack-blocking bulletproof glass according to different application scenarios. In some specific embodiments of the present invention, borosilicate glass is preferred when manufacturing basic bulletproof / auxiliary or special-purpose crack-blocking bulletproof glass; chemically tempered glass or tempered glass is preferred when manufacturing high-performance bulletproof / mainstream application-grade crack-blocking bulletproof glass; and aluminum-magnesium spinel glass is the first preferred material for manufacturing top-grade bulletproof / armor-grade crack-blocking bulletproof glass, sapphire (monocrystalline alumina) glass is the second preferred material, and chemically tempered high-alumina glass is the third preferred material.

[0038] The glass used to manufacture top-grade bulletproof / armor-grade crack-blocking bulletproof glass is expensive. A standard sapphire glass window pane (e.g., a Φ50mm circle, 3mm thick, optical grade) costs approximately RMB 500-2000 per piece, with the price increasing with size. Medium-sized armor-grade glass, such as 100mm×100mm and 10-15mm thick, is a common starting size for bulletproof applications, costing approximately RMB 20,000-80,000 per piece, with thickness significantly impacting price. Large-sized armor-grade glass, such as 200mm×300mm and 20mm+ thick, sees its price rise exponentially, with a single pane potentially costing between RMB 200,000 and 1 million. If cutting from ingots larger than 8 inches (200mm) increases the price even further. Extra-large custom orders, such as those for entire vehicle side windows, can cost several million RMB and typically require special production approval. The technical solution of this invention, however, utilizes stacked small glass panes to manufacture high-performance crack-blocking bulletproof glass, effectively reducing costs.

[0039] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0040] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains. Example 1

[0041] This embodiment prepares a crack-blocking bulletproof glass with a regular hexagonal sheet-like inorganic glass unit.

[0042] 1) Raw material and structural preparation: Both the back layer and the impact layer are made of polycarbonate sheets; the thickness of the impact layer is 8mm and the thickness of the back layer is 20mm.

[0043] The adhesive layer consists of three layers of stacked inorganic glass-polyurethane composite, integrally molded into a laminated film structure, as shown in the attached figure. Figure 3 As shown. Among them, the sheet-like inorganic glass unit is a regular hexagon with a thickness of 3mm and a side length of 40mm (d3), and the spacing between adjacent units is controlled to be 1mm (d4); the inorganic glass material is sapphire glass.

[0044] The polyurethane adhesive material is prepared according to the following mass ratio: 100 parts isocyanate, 50 parts polyester polyol, 30 parts polyether polyol, 10 parts small molecule polyol (1,4-butanediol), and 0.5 parts catalyst (dibutyltin dilaurate). After mixing and stirring, a polyurethane solution is formed.

[0045] 2) Preparation process Inorganic glass is precision cut into regular hexagonal sheet units with a side length of 40mm, and the edge burrs are removed.

[0046] The sheet unit was completely immersed in the above polyurethane solution for 10 minutes, and then placed in a vacuum chamber with a vacuum degree ≥ -0.09 MPa for 25 minutes to degas.

[0047] Hexagonal sheet-like units, coated with polyurethane solution and spaced 1 mm apart, are evenly laid on the surface of the back polycarbonate sheet to form the first inorganic glass-polyurethane composite layer, as shown in the attached figure. Figure 3 Green glass plates are distributed.

[0048] Using the first composite layer as a reference, the second layer unit is shifted 41mm to the right along the top edge of the regular hexagon, as shown in the attached figure. Figure 3 Purple glass; the third layer unit is translated 41mm along the upper left side of the regular hexagon, as shown in the attached diagram. Figure 3 The gray glass forms a three-dimensional staggered layout, which together constitutes the adhesive layer.

[0049] A polycarbonate sheet with an impact surface layer is placed on the surface of the third composite layer. The whole sheet is placed in a vacuum bag, vacuumed to ≥-0.09MPa and held for 25 minutes. Then it is placed in an autoclave and hot-pressed at 110℃ and 1.2MPa for 1.5 hours. After natural cooling to room temperature, the finished product is obtained. The overall thickness of the adhesive layer is 12mm.

[0050] The test sample was tested according to the GJB3030A-2021 standard for bulletproof transparent parts for armored vehicles. It was tested with a 12.7mm armor-piercing incendiary round, with a speed of 488mm / s, and a single round. The bulletproof level was C. No spatter was ejected from the back of the sample. The back surface was smooth. The fragmentation range showed that a single sapphire area was broken, and three adjacent sapphire glass pieces showed cracks. Example 2

[0051] This embodiment prepares a crack-blocking bulletproof glass with a square sheet-like inorganic glass unit.

[0052] The raw materials and preparation process are the same as in Example 1, with only the following targeted adjustments: (see attached) Figure 2As shown, the impact surface layer is 2mm thick, and the back layer is 40mm thick; the sheet-like inorganic glass units are squares with a thickness of 2mm and a side length of 30mm (d1), and the spacing between adjacent units is 1mm (d2); the inorganic glass material is high-alumina glass; the adhesive layer is a four-layer stacked structure; the specific arrangement is as follows: the square sheet-like units with polyurethane solution are evenly laid on the surface of the back layer polycarbonate sheet at a spacing of 1mm to form the first inorganic glass polyurethane composite layer, as shown in the attached figure. Figure 2 Green glass sheets are distributed; sheet-like units continue to be laid flat on the first composite layer, with adjacent units offset diagonally by 14.61 mm, as shown in the attached diagram. Figure 2 Purple glass slides are distributed; repeat this step to form a third composite layer, as shown in the attached image. Figure 2 Gray glass sheets are distributed; this step is repeated to form the fourth composite layer (the misaligned position is the same as the attached layer). Figure 2 The green glass sheets overlap (not shown in the figure) and together form the adhesive layer; the vacuum degassing and vacuuming parameters are the same as in Example 1, the high temperature hot pressing conditions are adjusted to 105℃ and 1.2MPa, and the hot pressing time is extended to 2h to ensure that the gaps are fully filled by the polyurethane solution and to ensure the interlayer bonding strength; the overall thickness of the adhesive layer is 10mm.

[0053] The test sample was tested according to the GJB3030A-2021 standard for bulletproof transparent parts for armored vehicles. It was tested with a 7.62mm armor-piercing incendiary round at 820mm / s, one round, with a bulletproof level of C. No spatter was ejected from the back of the sample. The back surface was smooth. The two adjacent high-alumina glass areas were broken, and the four adjacent high-alumina glass areas were cracked. Example 3

[0054] This embodiment prepares a crack-blocking bulletproof glass with hexagonal sheet-like inorganic glass units. The steps are the same as in Embodiment 1. The difference is that: the impact surface layer thickness is 3mm, and the back layer thickness is 40mm; the sheet-like inorganic glass units are selected from hexagonal chemically tempered glass with a thickness of 1mm and a side length of 40mm (d3), and the spacing between adjacent units is controlled to be 1mm (d4); the adhesive layer is a five-layer stacked structure; the specific arrangement is as follows: the hexagonal sheet-like units with polyurethane solution are evenly laid on the surface of the back layer polycarbonate sheet at a spacing of 1mm to form the first inorganic glass polyurethane composite layer, as shown in the attached figure. Figure 3 Green glass sheets are distributed; taking the first composite layer as a reference, the second layer unit is shifted 41mm to the right along the top edge of the regular hexagon, as shown in the attached figure. Figure 3 Purple glass; the third layer unit is translated 41mm along the upper left side of the regular hexagon, as shown in the attached diagram. Figure 3 Gray glass; the fourth layer of units is arranged the same as the first layer, with... Figure 3 Not shown in the middle; the fifth layer of units is arranged the same as the second layer, attached. Figure 3Not shown in the image; the above five splicing layers form a three-dimensional staggered layout, together constituting the adhesive layer.

[0055] The test sample was tested according to the GJB3030A-2021 standard for bulletproof transparent parts for armored vehicles. It was tested with 5.8mm ordinary bullets (steel core), at a speed of 950mm / s, for 3 rounds. The bulletproof level was C. There was no spatter on the back of the sample. The back surface was smooth. The breakage range was such that a single tempered glass area broke at the point of each bullet, and three adjacent tempered glass pieces cracked.

[0056] Comparative Example Similar to Example 3, the difference is that the 1mm thick chemically tempered glass used in each layer of the adhesive layer is a single plate structure, rather than a spliced ​​structure of sheet glass.

[0057] The test sample was tested according to the GJB3030A-2021 standard for bulletproof transparent parts for armored vehicles. It was tested with 5.8mm ordinary bullets (steel core), at a speed of 950mm / s, for 3 rounds. The bulletproof level was C. There was no spatter on the back of the sample. The back surface was smooth. The tempered glass area with a diameter of φ150mm was broken at the point of each bullet. The bulletproof glass was cracked all over.

[0058] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A crack-blocking bulletproof glass, characterized in that, It includes: The back layer is made of polycarbonate. An adhesive layer is disposed on the surface of the back layer; the adhesive layer is a multi-layered inorganic glass polyurethane composite layer integrally formed laminated film structure; the inorganic glass polyurethane composite layer is composed of discretely distributed sheet-like inorganic glass units and polyurethane adhesive material; in each layer of the inorganic glass polyurethane composite layer, the sheet-like inorganic glass units are arranged in a spaced-apart, flat manner, with a spacing of 1~2mm between adjacent sheet-like inorganic glass units, and the polyurethane adhesive material fills the surface of the sheet-like inorganic glass units and the gaps between adjacent units; the sheet-like inorganic glass units in adjacent layers of the inorganic glass polyurethane composite layer are arranged in a staggered manner, and the staggered direction is parallel to the arrangement plane; the polyurethane adhesive material has an elongation at break ≥400%, tensile strength ≥28MPa, and light transmittance ≥90%; The impact surface layer, made of polycarbonate, is disposed on the surface of the adhesive layer away from the back layer; the back layer, adhesive layer, and impact surface layer are bonded together as an integral structure by the polyurethane adhesive material through a high-temperature hot-pressing process.

2. The crack-blocking bulletproof glass according to claim 1, characterized in that, The sheet-like inorganic glass unit is a square structure with a side length of 20-60mm, and the square inorganic glass units in adjacent inorganic glass polyurethane composite layers are staggered along the diagonal; the adhesive layer is an N-layer inorganic glass polyurethane composite layer, where N is an integer ≥3; the side length of the sheet-like inorganic glass unit is d1, and the spacing between adjacent sheet-like inorganic glass units is d2; the misalignment dimension between adjacent inorganic glass polyurethane composite layers is... When N > 3, the arrangement positions of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers are the same as the arrangement positions of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥ 1.

3. The crack-blocking bulletproof glass according to claim 1, characterized in that, The sheet-like inorganic glass unit is a regular hexagonal structure with a side length of 10~40mm. The regular hexagonal inorganic glass units in the adjacent inorganic glass polyurethane composite layers are shifted and misaligned along the interlayer. The adhesive layer is an inorganic glass polyurethane composite layer with N layers stacked together, where N is an integer ≥3. The side length of the sheet-like inorganic glass unit is d3, and the distance between adjacent sheet-like inorganic glass units is d4. Taking the first layer as the reference, the second layer is shifted by a distance d3+d4 along the first side length direction of the regular hexagon. The third layer is shifted by a distance d3+d4 along the second side length direction of the regular hexagon. The first side length and the second side length are adjacent side lengths. When N>3, the arrangement position of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers is the same as the arrangement position of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥1.

4. The crack-blocking bulletproof glass according to claim 1, characterized in that, The thickness of the impact surface layer is 2~8mm, and the thickness of the back surface layer is 20~40mm.

5. The crack-blocking bulletproof glass according to claim 1, characterized in that, The thickness of the sheet-like inorganic glass unit is 1~3mm, and the thickness of the interlayer adhesive layer is 0.2~1mm.

6. A method for preparing crack-blocking bulletproof glass, characterized in that, Includes the following steps: S1 processes inorganic glass into discretely distributed sheet-like inorganic glass units; the sheet-like inorganic glass units have a planar structure; S2. The sheet-like inorganic glass unit is immersed in a polyurethane solution and then degassed under vacuum. The polyurethane adhesive material formed after the polyurethane solution is cured has an elongation at break ≥400%, a tensile strength ≥28MPa, and a light transmittance ≥90%. S3 involves arranging sheet-like inorganic glass units with polyurethane solution adhering to them in a flat, spaced manner on the surface of polycarbonate material. The spacing between adjacent sheet-like inorganic glass units is controlled to be 1-2 mm, forming the first inorganic glass polyurethane composite layer. S4 On the first inorganic glass polyurethane composite layer, continue to lay and arrange sheet-like inorganic glass units with polyurethane solution adhering to them, so that the sheet-like inorganic glass units of adjacent layers are staggered and the staggered direction is parallel to the arrangement plane, forming a second and above inorganic glass polyurethane composite layer. S5 covers the surface of the last inorganic glass polyurethane composite layer with polycarbonate material, and places the whole in a vacuum bag for vacuuming and high-temperature hot pressing treatment to cure the multi-layer inorganic glass polyurethane composite layer, forming an integrally molded laminated film structure, which is tightly bonded to the polycarbonate material on both sides to obtain crack-blocking bulletproof glass; the high-temperature hot pressing temperature is 110±10℃ and the pressure is 1.2±0.2MPa.

7. The preparation method according to claim 6, characterized in that, The sheet-like inorganic glass unit is processed into a square structure with a side length of 20-60mm; adjacent layers of sheet-like inorganic glass units are staggered along the diagonal direction; the laminated film structure includes N layers of inorganic glass polyurethane composite layers stacked together, where N is an integer ≥3; the side length of the sheet-like inorganic glass unit is d1, and the spacing between adjacent sheet-like inorganic glass units is d2; the staggered dimension between adjacent layers is... When N > 3, the arrangement positions of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers are the same as the arrangement positions of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥ 1.

8. The preparation method according to claim 6, characterized in that, The sheet-like inorganic glass unit is processed into a regular hexagonal structure with a side length of 10~40mm; adjacent sheets-like inorganic glass units are shifted and staggered along the interlayer; the laminated film structure is an inorganic glass polyurethane composite layer with N layers stacked together, where N is an integer ≥3; the side length of the sheet-like inorganic glass unit is d3, and the spacing between adjacent sheet-like inorganic glass units is d4; taking the first layer as a reference, the second layer is shifted by a distance of d3+d4 along the first side length direction of the regular hexagon; the third layer is shifted by a distance of d3+d4 along the second side length direction of the regular hexagon; the first side length and the second side length are adjacent side lengths; when N>3, the arrangement positions of the sheet-like inorganic glass units in the 3n+1, 3n+2, and 3n+3 layers are the same as the arrangement positions of the sheet-like inorganic glass units in the first, second, and third layers, where n is an integer ≥1.

9. The preparation method according to any one of claims 6 to 8, characterized in that, The polyurethane solution is prepared by mixing isocyanate, polyester polyol, polyether polyol, small molecule polyol and catalyst.

10. The application of a crack-blocking bulletproof glass according to any one of claims 1 to 5 in a protective scenario where both bulletproof performance and visibility need to be maintained.

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