Composite bulletproof plugboard and preparation method thereof

Abstract

The invention relates to the technical field of bulletproof plugboards, in particular to a composite bulletproof plugboard and a preparation method thereof. The composite bulletproof flashboard comprises a crack arrest layer, a composite ceramic layer, a buffer layer, a tough layer and an outer packing material which are arranged in a stacked mode. All the layers are bonded by adopting polyethylene adhesive films. The overall density of the composite bulletproof flashboard does not exceed 38.9 kg / m < 2 >, the composite bulletproof flashboard is light in weight, after a shooting experiment is conducted, the sunken degree of the back of the composite bulletproof flashboard does not exceed 18.4 mm, most importantly, the composite bulletproof flashboard still has good protection performance after multiple times of dense shooting and shooting again, and soldiers can be effectively protected and casualties can be effectively reduced in actual combats.

Description

Technical Field

[0001] The present invention relates to the technical field of bulletproof insert plates, and in particular to a composite bulletproof insert plate and a preparation method thereof. Background Art

[0002] Bulletproof plates are important protective equipment that protect a soldier's body from bullets, and are usually used together with bulletproof vests or tactical vests. Bulletproof plates can improve a soldier's combat capability and survivability, and play an important role in reducing casualties and enhancing combat effectiveness. Traditional bulletproof plates are made of single-layer materials. Due to their simple material and structure, they can provide partial protection, but they are heavy, rigid, and unstable in performance, making it difficult to meet the needs of modern military operations.

[0003] Composite or combined structure bulletproof inserts are the focus of current and future development. They are mainly divided into outer layer, middle layer and inner layer. The outer layer is usually made of high-strength fiber (such as Kevlar, carbon fiber, etc.) to initially block and disperse the energy of bullets; the middle layer is usually made of high-performance composite materials (such as UHMWPE, ceramics, etc.) to absorb and disperse most of the impact energy; the inner layer is usually made of soft materials (such as aramid fiber, foam, etc.) to provide additional cushioning and comfort.

[0004] Patent technology document CN115406307B A bulletproof plug plate based on oxide filament reinforced ceramic composite material and its preparation method, the bulletproof plug plate includes mutually bonded packaging layer, ceramic layer, buffer layer and toughness layer from the explosion surface to the explosion surface; compared with the prior art, the invention effectively improves the toughness of alumina bulletproof ceramics, thereby significantly reducing the penetration depth and improving the anti-ballistic performance of the composite target plate. Patent technology document CN115420146B A novel lightweight bulletproof plug plate protection structure and its preparation method, the novel lightweight bulletproof plug plate described in the invention is composed of a crack arresting layer, a ceramic layer, a fiber layer and a depression reducing layer in the direction of the bullet.

[0005] Although the above patents all have good protective performance, their protective performance after being subjected to intensive bullet shooting still needs to be improved. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a composite bulletproof insert plate to solve the problem that the traditional bulletproof insert plate has poor protective performance after being subjected to intensive shooting of multiple bullets.

[0007] Based on the above purpose, the present invention provides a composite bulletproof plug plate, which includes a stacked crack-stop layer, a composite ceramic layer, a buffer layer, a toughness layer and an outer packaging material; the layers are bonded with a polyethylene film; The specific preparation steps of the composite ceramic layer are as follows: S1: Mix the carbon fiber and acetone, and after ultrasonic homogenization, react at 70°C for 20-24h, filter and dry, then put it into acidified liquid, react at 75-85°C for 2-3h, centrifuge, filter, wash and dry to obtain pretreated carbon fiber; S2: mixing the pretreated carbon fiber, γ-aminopropyltriethoxysilane solution and ethanol, reacting at 75-80° C. for 4 h, centrifuging, filtering, washing and drying to obtain amino carbon fiber; S3: mixing the aminated carbon fiber, graphene oxide and N,N-dimethylformamide, reacting at 100-110° C. for 4 h, centrifuging, filtering, washing and drying to obtain graphene-grafted carbon fiber; S4: placing the graphene-grafted carbon fiber in a 40 wt% polysilazane precursor solution, then adding graphene oxide, stirring evenly, standing for 10-20 hours, centrifuging, filtering, and drying to obtain modified carbon fiber; S5: mixing the modified carbon fiber, the alumina particles and the hybrid fiber, pressing and sintering them to obtain a composite ceramic layer; Preferably, the acidifying solution in step S1 is a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1.

[0008] Preferably, in step S2, the usage ratio of the pretreated carbon fiber, the γ-aminopropyltriethoxysilane solution and the ethanol is 10-15 g: 80-100 ml: 300-400 ml.

[0009] Preferably, in step S3, the weight ratio of the amination carbon fiber, graphene oxide and N,N-dimethylformamide is 10-15:0.5-1:1500.

[0010] Preferably, in step S4, the amount ratio of the graphene-grafted carbon fiber, the polysilazane precursor solution and the graphene oxide dispersion is 5-10 g: 100-200 ml: 10-15 ml.

[0011] Preferably, the graphene oxide dispersion in step S4 is graphene oxide dispersed in NMP solution, and the content of graphene oxide is 4wt%.

[0012] Preferably, the mixed fibers in step S5 are a mixture of third-generation silicon carbide short fiber powder and metal short fiber powder in a weight ratio of 1:1.

[0013] Preferably, in step S5, the weight ratio of the modified carbon fiber, the alumina particles, and the mixed fiber is 5-10:80-90:5-10.

[0014] Preferably, the sintering parameters in step S5 are: temperature of 1650-1750° C., and pressure of 56-60 MPa.

[0015] Preferably, the crack-stop layer is a lightweight aluminum alloy with a thickness of 1-3 mm.

[0016] Preferably, the thickness of the composite ceramic layer is 10-15 mm.

[0017] Preferably, the buffer layer is formed by sequentially stacking aramid non-woven fabric and PE non-woven fabric, and each layer is bonded with a polyethylene film, and the total surface density of the buffer layer is 10-12 kg / m.

[0018] Preferably, the single-layer surface density of the aramid non-woven fabric is 190-230 g / m, and the single-layer surface density of the PE non-woven fabric is 100-150 g / m.

[0019] Preferably, the thickness of the buffer layer is 8-10 mm.

[0020] Preferably, the toughness layer is an ultra-high molecular weight polyethylene fiber fabric with a thickness of 8-10 mm.

[0021] Preferably, the ultra-high molecular weight polyethylene fiber fabric is laminated by two-dimensional woven fabrics, and the surface density is 100-200g / m Preferably, the outer packaging material is waterproof Oxford cloth.

[0022] Preferably, the length of the carbon fiber is 50-70 μm.

[0023] Furthermore, the present invention also provides a method for preparing a composite bulletproof insert, and the specific preparation steps are as follows: The buffer layer is obtained by vacuum hot pressing in the order of aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric using an autoclave; (2) The composite bulletproof plate is formed by vacuum hot pressing in an autoclave in the order of crack arrest layer - polyethylene film - composite ceramic layer - polyethylene film - buffer layer - polyethylene film - toughness layer, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof plate.

[0024] Beneficial effects of the present invention: The present invention performs graphene oxide grafting treatment on the surface of carbon fiber and impregnates it with graphene oxide dispersion, so as to form slip between graphenes in the form of chemical grafting and physical surface impregnation. This slip effect can release the stress during impact, thereby making the composite bulletproof insert plate still have relatively excellent protective performance after being hit by multiple bullets.

[0025] The present invention can generate a ceramic reinforcement phase in situ by impregnating a polysilazane precursor solution on the surface of the carbon fiber and then undergoing a subsequent high-temperature sintering treatment, thereby improving the protective performance of the composite bulletproof insert.

[0026] The present invention not only improves the protective performance of the composite bulletproof insert plate against a single bullet impact by modifying the carbon fiber, but also enables the composite bulletproof insert plate to still have relatively excellent protective performance after being intensively hit by multiple bullets. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0028] Embodiment 1: A composite bulletproof insert, the specific preparation steps are as follows: (1) Mix 30g of carbon fiber and 1000ml of acetone, and then react at 70℃ for 20h after ultrasonic homogenization. Centrifuge and dry under vacuum, and then place in acidified solution (V 浓硫酸 :V 浓硝酸 The reaction was carried out at 75°C for 2 hours, and then the mixture was centrifuged and filtered, and then washed until the pH value was 7, and finally vacuum dried to obtain pretreated carbon fiber; (2) 10 g of pretreated carbon fiber, 80 ml of γ-aminopropyltriethoxysilane solution and 300 ml of ethanol were mixed, reacted at 75 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain amino carbon fiber; (3) 10 g of amino carbon fiber, 0.5 g of graphene oxide and 1500 g of N,N-dimethylformamide were mixed, reacted at 100 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain graphene-grafted carbon fiber; (4) Place 5 g of graphene-grafted carbon fiber in 100 ml of 40 wt% Durazane™ 1800 solution, then add 10 ml of 4 wt% graphene oxide dispersion, stir evenly, let stand for 10 h, centrifuge, filter, and vacuum dry at 150 °C for 1 h to obtain modified carbon fiber; (5) 5 g of modified carbon fiber, 80 g of alumina particles, 2.5 g of third-generation silicon carbide short fiber powder, and 2.5 g of metal short fiber powder were mixed, pressed and molded, and kept at 1650 ° C and a pressure of 56 MPa for 10 min to obtain a 10 mm composite ceramic layer; (6) using an autoclave to vacuum press and form the following steps in the order of aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric to obtain a buffer layer with a total surface density of 10 kg / m; (7) The composite bulletproof plate is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 1 mm, the thickness of the buffer layer is 8 mm, and the thickness of the toughness layer is 8 mm.

[0029] Embodiment 2: A composite bulletproof insert, the specific preparation steps are as follows: (1) 30 g of carbon fiber and 1000 ml of acetone were mixed, ultrasonically homogenized, reacted at 70 °C for 22 h, centrifuged and vacuum dried, and then placed in an acidified solution (V 浓硫酸 :V 浓硝酸 The reaction was carried out at 80°C for 2 hours, and then the mixture was centrifuged and filtered, and then washed until the pH value was 7, and finally vacuum dried to obtain pretreated carbon fiber; (2) 13 g of pretreated carbon fiber, 90 ml of γ-aminopropyltriethoxysilane solution and 350 ml of ethanol were mixed, reacted at 78 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain amino carbon fiber; (3) 13 g of amino carbon fiber, 0.8 g of graphene oxide and 1500 g of N,N-dimethylformamide were mixed, reacted at 105 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain graphene-grafted carbon fiber; (4) 8 g of graphene-grafted carbon fiber was placed in 150 ml of 40 wt% Durazane™ 1800 solution, and then 13 ml of 4 wt% graphene oxide dispersion was added. After stirring evenly, the mixture was allowed to stand for 15 h, centrifuged, filtered, and vacuum dried at 150 °C for 1 h to obtain modified carbon fiber. (5) 8 g of modified carbon fiber, 85 g of alumina particles, 4 g of third-generation silicon carbide short fiber powder, and 4 g of metal short fiber powder were mixed, pressed and molded, and kept at 1700 ° C and a pressure of 58 MPa for 13 min to obtain a 13 mm composite ceramic layer; (6) using an autoclave to vacuum press the aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric in the order of forming to obtain a buffer layer with a total surface density of 11 kg / m; (7) The composite bulletproof plate is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 2 mm, the thickness of the buffer layer is 9 mm, and the thickness of the toughness layer is 9 mm.

[0030] Embodiment 3: A composite bulletproof insert, the specific preparation steps are as follows: (1) 30 g of carbon fiber and 1000 ml of acetone were mixed, ultrasonically homogenized, reacted at 70 °C for 24 h, centrifuged and vacuum dried, and then placed in an acidified solution (V 浓硫酸 :V 浓硝酸 The carbon fiber was reacted at 85°C for 3 hours, centrifuged and filtered, washed until the pH value was 7, and finally vacuum dried to obtain pretreated carbon fiber; (2) 15 g of pretreated carbon fiber, 100 ml of γ-aminopropyltriethoxysilane solution and 400 ml of ethanol were mixed, reacted at 80 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain amino carbon fiber; (3) 15 g of amino carbon fiber, 1 g of graphene oxide and 1500 g of N,N-dimethylformamide were mixed, reacted at 110 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain graphene-grafted carbon fiber; (4) Place 10 g of graphene-grafted carbon fiber in 200 ml of 40 wt% Durazane™ 1800 solution, then add 15 ml of 4 wt% graphene oxide dispersion, stir evenly, let stand for 20 h, centrifuge, filter, and vacuum dry at 150 °C for 1 h to obtain modified carbon fiber; (5) 10 g of modified carbon fiber, 80 g of alumina particles, 5 g of third-generation silicon carbide short fiber powder, and 5 g of metal short fiber powder were mixed, pressed and molded, and kept at 1750 ° C and a pressure of 60 MPa for 15 min to obtain a 15 mm composite ceramic layer; (6) using an autoclave to vacuum press and form the following steps: aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric to obtain a buffer layer with a total surface density of 12 kg / m; (7) The composite bulletproof insert is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 3 mm, the thickness of the buffer layer is 10 mm, and the thickness of the toughness layer is 10 mm.

[0031] Comparative Example 1: A bulletproof insert, the specific preparation steps are as follows: The difference from Example 2 is that the carbon fiber is not subjected to the graphene oxide grafting treatment. The specific preparation steps are as follows: (1) 8 g of carbon fiber was placed in 150 ml of 40 wt% Durazane™ 1800 solution, and then 13 ml of 4 wt% graphene oxide dispersion was added. After stirring evenly, the mixture was allowed to stand for 15 h, centrifuged, filtered, and vacuum dried at 150 °C for 1 h to obtain modified carbon fiber. (2) 8 g of modified carbon fiber, 85 g of alumina particles, 4 g of third-generation silicon carbide short fiber powder, and 4 g of metal short fiber powder were mixed, pressed and molded, and kept at 1700 ° C and a pressure of 58 MPa for 13 min to obtain a 13 mm composite ceramic layer; (3) using an autoclave to vacuum press the aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric in the order of forming to obtain a buffer layer with a total surface density of 11 kg / m; (4) The composite bulletproof plate is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 2 mm, the thickness of the buffer layer is 9 mm, and the thickness of the toughness layer is 9 mm.

[0032] Comparative Example 2: A bulletproof insert, the specific preparation steps are as follows: The difference from Example 2 is that when impregnating the graphene-grafted carbon fiber, 13 ml of 4 wt% graphene oxide dispersion is not added. The specific preparation steps are as follows: (1) 30 g of carbon fiber and 1000 ml of acetone were mixed, ultrasonically homogenized, reacted at 70 °C for 22 h, centrifuged and vacuum dried, and then placed in an acidified solution (V 浓硫酸 :V 浓硝酸 The reaction was carried out at 80°C for 2 hours, and then the mixture was centrifuged and filtered, and then washed until the pH value was 7, and finally vacuum dried to obtain pretreated carbon fiber; (2) 13 g of pretreated carbon fiber, 90 ml of γ-aminopropyltriethoxysilane solution and 350 ml of ethanol were mixed, reacted at 78 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain amino carbon fiber; (3) 13 g of amino carbon fiber, 0.8 g of graphene oxide and 1500 g of N,N-dimethylformamide were mixed, reacted at 105 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain graphene-grafted carbon fiber; (4) 8 g of graphene-grafted carbon fiber was placed in 150 ml of 40 wt% Durazane™ 1800 solution, stirred evenly, allowed to stand for 15 h, centrifuged, filtered, and vacuum dried at 150 °C for 1 h to obtain modified carbon fiber; (5) 8 g of modified carbon fiber, 85 g of alumina particles, 4 g of third-generation silicon carbide short fiber powder, and 4 g of metal short fiber powder were mixed, pressed and molded, and kept at 1700 ° C and a pressure of 58 MPa for 13 min to obtain a 13 mm composite ceramic layer; (6) using an autoclave to vacuum press the aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric in the order of forming to obtain a buffer layer with a total surface density of 11 kg / m; (7) The composite bulletproof plate is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 2 mm, the thickness of the buffer layer is 9 mm, and the thickness of the toughness layer is 9 mm.

[0033] Comparative Example 3: A bulletproof insert, the specific preparation steps are as follows: (1) 30 g of carbon fiber and 1000 ml of acetone were mixed, ultrasonically homogenized, reacted at 70 °C for 22 h, centrifuged and vacuum dried, and then placed in an acidified solution (V 浓硫酸 :V 浓硝酸 The reaction was carried out at 80°C for 2 hours, and then the mixture was centrifuged and filtered, and then washed until the pH value was 7, and finally vacuum dried to obtain pretreated carbon fiber; (2) 13 g of pretreated carbon fiber, 90 ml of γ-aminopropyltriethoxysilane solution and 350 ml of ethanol were mixed, reacted at 78 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain amino carbon fiber; (3) 13 g of amino carbon fiber, 0.8 g of graphene oxide and 1500 g of N,N-dimethylformamide were mixed, reacted at 105 ° C for 4 h, centrifuged, filtered, added with deionized water and anhydrous ethanol for shaking washing, centrifuged, and vacuum dried at 80 ° C for 24 h to obtain graphene-grafted carbon fiber; (4) 7.5 g of graphene-grafted carbon fiber, 0.5 g of SiCN, 85 g of alumina particles, 4 g of third-generation silicon carbide short fiber powder, and 4 g of metal short fiber powder were mixed, pressed and molded, and kept at 1700 ° C and a pressure of 58 MPa for 13 min to obtain a 13 mm composite ceramic layer; (5) using an autoclave to vacuum press and form the following steps in the order of aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric to obtain a buffer layer with a total surface density of 11 kg / m; (6) The composite bulletproof plate is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 2 mm, the thickness of the buffer layer is 9 mm, and the thickness of the toughness layer is 9 mm.

[0034] Comparative Example 4: A bulletproof insert, the specific preparation steps are as follows: (1) 8 g of carbon fiber, 85 g of alumina particles, 4 g of third-generation silicon carbide short fiber powder, and 4 g of metal short fiber powder were mixed, pressed and molded, and kept at 1700 ° C and a pressure of 58 MPa for 13 min to obtain a 13 mm composite ceramic layer; (2) using an autoclave to vacuum press the aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric in the order of forming to obtain a buffer layer with a total surface density of 11 kg / m; (3) The composite bulletproof plate is formed by vacuum hot pressing in the order of crack-stop layer-polyethylene film-composite ceramic layer-polyethylene film-buffer layer-polyethylene film-toughness layer using an autoclave, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof insert, wherein the thickness of the crack-stop layer is 2 mm, the thickness of the buffer layer is 9 mm, and the thickness of the toughness layer is 9 mm.

[0035] Performance Testing The ballistic performance test was conducted according to the GJB 4300A-2012 military bulletproof vest safety technical performance requirements, using a 7.62 mm ballistic gun; the test bullet was a 53-type 7.62 mm armor-piercing incendiary bullet (speed-adjustable bullet); the shooting distance was 15 m, the impact speed was 878±10 m / s, and the incident angle was 0°. Ten random shots were conducted on each sample, and the depth of the dent caused by each shot was recorded and the average value was taken. The test results are shown in Table 1. Take another series of samples and test them with a 7.62 mm ballistic gun; test bullet: Type 53 7.62 mm armor-piercing incendiary bullet (speed-adjustable bullet); shooting distance 15 m, impact speed 878±10 m / s, 0° shooting angle of incidence. Each sample is shot 4 times in total. The impact points of the first three shots are distributed in a triangular shape. The distance between the first three shots is 50 mm, and the fourth shot is located at the center of the impact points of the first three shots. Repeat three times, record the depth of the depression caused by the last shot of each shot and take the average value. The test results are shown in Table 1.

[0036]

[0037] Data analysis shows that, through Examples 1-3, the overall density of the composite bulletproof insert of the present invention does not exceed 38.9 kg / m 2 After the shooting experiment, the degree of depression on its back did not exceed 18.4mm. Most importantly, after being shot many times and being shot again, it still had good protective performance. In actual combat, it could effectively protect our soldiers and reduce casualties.

[0038] It can be seen from Example 2 and Comparative Examples 1 and 2 that the present invention performs a surface-grafting graphene oxide treatment on carbon fiber and impregnates it with a graphene oxide dispersion. On the one hand, in the subsequent high-temperature sintering process, the internal structure of the composite ceramic layer obtained after sintering is made more compact, thereby improving the protective performance of the composite bulletproof insert plate; on the other hand, the chemically grafted graphene and the graphene deposited on the surface by a physical method are stacked on each other, so that slip is formed between the graphenes. This slip effect can release the stress during impact, thereby making the composite bulletproof insert plate still have relatively excellent protective performance after being intensively hit by multiple bullets.

[0039] It can be seen from Example 2 and Comparative Example 3 that the present invention can generate a ceramic reinforcement in situ by impregnating the surface of the carbon fiber with a polysilazane precursor solution and then subjecting it to a subsequent high-temperature sintering treatment. Compared with directly adding ceramics, the in-situ generation method can make its internal structure more uniform and compact, thereby improving the protective performance of the composite bulletproof insert.

[0040] It can be seen from Example 2 and Comparative Example 3 that the present invention not only improves the protective performance of the composite bulletproof insert against bullet impact by modifying the carbon fiber, but also enables the composite bulletproof insert to still have relatively excellent protective performance after being intensively hit by multiple bullets.

[0041] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A composite bulletproof insert, characterized in that: The composite bulletproof insert plate comprises a crack-stop layer, a composite ceramic layer, a buffer layer, a toughness layer and an outer packaging material which are stacked; each layer is bonded with a polyethylene film; The specific preparation steps of the composite ceramic layer are as follows: S1: Mix the carbon fiber and acetone, and after ultrasonic homogenization, react at 70°C for 20-24h, filter and dry, then put it into acidified liquid, react at 75-85°C for 2-3h, centrifuge, filter, wash and dry to obtain pretreated carbon fiber; S2: mixing the pretreated carbon fiber, γ-aminopropyltriethoxysilane solution and ethanol, reacting at 75-80° C. for 4 h, centrifuging, filtering, washing and drying to obtain amino carbon fiber; S3: mixing the aminated carbon fiber, graphene oxide and N,N-dimethylformamide, reacting at 100-110° C. for 4 h, centrifuging, filtering, washing and drying to obtain graphene-grafted carbon fiber; S4: placing the graphene-grafted carbon fiber in a 40 wt% polysilazane precursor solution, then adding graphene oxide, stirring evenly, standing for 10-20 hours, centrifuging, filtering, and drying to obtain modified carbon fiber; S5: The modified carbon fibers, alumina particles, and hybrid fibers are mixed, pressed into shape, and sintered to obtain a composite ceramic layer.

2. The composite bulletproof insert according to claim 1, characterized in that: The crack arresting layer is a lightweight aluminum alloy with a thickness of 1-3 mm.

3. The composite bulletproof insert according to claim 1, characterized in that: The buffer layer is formed by sequentially stacking aramid non-woven fabric and PE non-woven fabric, and each layer is bonded by polyethylene film. The total surface density of the buffer layer is 10-12 kg / m, and the thickness is 8-10 mm.

4. The composite bulletproof insert according to claim 1, characterized in that: The toughness layer is made of ultra-high molecular weight polyethylene fiber fabric with a thickness of 8-10 mm.

5. The composite bulletproof insert according to claim 1, characterized in that: The outer packaging material is waterproof Oxford cloth.

6. The composite bulletproof insert according to claim 1, characterized in that: The amount ratio of the pretreated carbon fiber, γ-aminopropyltriethoxysilane solution and ethanol in step S2 is 10-15g:80-100ml:300-400ml.

7. The composite bulletproof insert according to claim 1, characterized in that: The weight ratio of the amino carbon fiber, graphene oxide and N,N-dimethylformamide in step S3 is 10-15:0.5-1:1500.

8. The composite bulletproof insert according to claim 1, characterized in that: In step S4, the amount ratio of the graphene-grafted carbon fiber, the polysilazane precursor solution and the graphene oxide dispersion is 5-10 g: 100-200 ml: 10-15 ml.

9. The composite bulletproof insert according to claim 1, characterized in that: In step S5, the weight ratio of the modified carbon fiber, the alumina particles, and the mixed fiber is 5-10:80-90:5-10.

10. A method for preparing a composite bulletproof insert according to any one of claims 1 to 9, characterized in that: The steps include: (1) vacuum hot pressing is performed in an autoclave in the order of aramid non-woven fabric-polyethylene film-PE non-woven fabric-polyethylene film-aramid non-woven fabric to obtain a buffer layer; (2) The composite bulletproof plate is formed by vacuum hot pressing in an autoclave in the order of crack arrest layer - polyethylene film - composite ceramic layer - polyethylene film - buffer layer - polyethylene film - toughness layer, and finally packaged with waterproof Oxford cloth to obtain a composite bulletproof plate.

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