阅读说明：本技术 一种一体化结构的吸波隐身防弹板及其制备方法 (Wave-absorbing stealth bulletproof plate with integrated structure and preparation method thereof ) 是由 黄小忠 陈解放 鲁先孝 刘鹏 于 2020-10-12 设计创作，主要内容包括：本发明公开了一种一体化结构的吸波隐身防弹板及其制备方法。述隐身防弹板从外至里依次包含玻璃钢板层、隐身防弹层、碳纤维复合材料层；所述隐身防弹层由纤维增强复合材料层与吸波材料层交替层叠获得,所述纤维增强复合材料层中的复合材料为超高分子量聚乙烯纤维增强聚乙烯基复合材料或芳纶纤维环氧树脂基复合材料,所述隐身防弹板的厚度≤23mm。制备方法是将纤维增强材料、吸波材料层交替层叠成型隐身防弹层,再将隐身防弹层、玻璃钢板层、碳纤维复合材料层进行粘合,将粘好的隐身防弹板压制,封边即得吸波隐身防弹板。本发明制备的一体化隐身防弹板不仅质量轻、厚度薄,而且能够抵御步枪射击、具有优异的吸波性能,制备方法简单。(The invention discloses a wave-absorbing stealth bulletproof plate with an integrated structure and a preparation method thereof. The stealth bulletproof plate sequentially comprises a glass fiber reinforced plastic plate layer, a stealth bulletproof layer and a carbon fiber composite material layer from outside to inside; the stealth bulletproof layer is obtained by alternately laminating fiber reinforced composite material layers and wave-absorbing material layers, the composite material in the fiber reinforced composite material layers is an ultrahigh molecular weight polyethylene fiber reinforced polyethylene-based composite material or an aramid fiber epoxy resin-based composite material, and the thickness of the stealth bulletproof layer is less than or equal to 23 mm. The preparation method comprises the steps of alternately laminating fiber reinforced materials and wave-absorbing material layers to form the stealth bulletproof layer, then bonding the stealth bulletproof layer, the glass fiber reinforced plastic plate layer and the carbon fiber composite material layer, pressing the bonded stealth bulletproof plate, and performing edge sealing to obtain the wave-absorbing stealth bulletproof plate. The integrated stealth bulletproof plate prepared by the invention is light in weight, thin in thickness, capable of resisting rifle shooting, excellent in wave absorbing performance and simple in preparation method.)

1. The utility model provides a stealthy armour of inhaling ripples of integral structure which characterized in that: the stealth bulletproof plate sequentially comprises a glass fiber reinforced plastic plate layer, a stealth bulletproof layer and a carbon fiber composite material layer from outside to inside; the stealth bulletproof layer is obtained by alternately laminating fiber reinforced composite material layers and wave-absorbing material layers, the fiber reinforced composite material in the fiber reinforced composite material layers is an ultrahigh molecular weight polyethylene fiber reinforced polyethylene-based composite material or an aramid fiber epoxy resin-based composite material, and the thickness of the stealth bulletproof layer is less than or equal to 23 mm.

2. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 1, characterized in that: the thickness of the glass fiber reinforced plastic plate layer is 0.3 mm-2 mm, the thickness of the stealth bulletproof layer is 18-22 mm, and the thickness of the carbon fiber composite material layer is 0.1 mm-1 mm.

3. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 1, characterized in that: in the stealth bulletproof layer, the bottommost layer and the topmost layer are fiber reinforced composite material layers and comprise 2-6 fiber reinforced composite material layers and 1-5 wave-absorbing material layers, the thickness of any one fiber reinforced composite material layer is 1-8 mm, and the thickness of any one wave-absorbing material layer is 0.01-0.5 mm.

4. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 1, characterized in that:

in the stealth bulletproof layer, the thickness of the fiber reinforced composite material layer of the (N + 1) th layer is larger than or equal to that of the fiber reinforced composite material layer of the Nth layer.

5. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 1, characterized in that: the surface density of the stealth bulletproof plate is less than or equal to 23Kg/m²。

6. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 1, characterized in that: the wave-absorbing material layer is at least one selected from a resistance film, an iron coating carbon fiber magnetic material film and a metamaterial film.

7. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 1, characterized in that:

the preparation process of the iron coating carbon fiber magnetic material film comprises the following steps: spraying a layer of epoxy glue on the release film, uniformly dispersing the carbon fiber with the pyrolytic carbonyl iron coating on the epoxy glue, and curing at normal temperature to obtain the carbon fiber release film;

the preparation method of the carbon fiber with the pyrolytic carbonyl iron coating comprises the following steps: dispersing the pretreated carbon fiber in xylene to obtain a solution containing carbon fiber, then adding carbonyl iron to obtain slurry, carrying out pyrolysis reaction under a protective atmosphere, carrying out solid-liquid separation, cleaning the obtained solid phase, soaking the solid phase in a mixed solution containing a coupling agent, and drying to obtain the coated carbon fiber.

8. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 7, characterized in that:

the mass ratio of the carbon fibers to the xylene is 0.5: 9-15;

the mass ratio of the carbon fibers to the carbonyl iron is 0.5: 1-3.

9. The wave-absorbing stealthy bulletproof plate with an integrated structure according to claim 7, characterized in that:

the procedure of the pyrolysis reaction is as follows: heating to 90-110 ℃ from normal temperature for 40-80 min, then heating to 120-140 ℃ for 300-420 min, then heating to 150-160 ℃ for 2000-3000 min, preserving heat for 2000-3000 min at 150-160 ℃, and then cooling to normal temperature for 60-180 min;

and carrying out pyrolysis reaction under stirring, wherein the stirring mode is that stirring is carried out for 1-2 min at a rotating speed of 30-60 r/min, and then stirring is carried out for 1-5 min at a rotating speed of 20-30 r/min at intervals of 1-2 h.

10. The method for preparing the wave-absorbing stealth bulletproof plate with an integrated structure according to claims 1-9, which is characterized in that: the method comprises the following steps:

step one preparation of stealth bulletproof layer

Alternately stacking and laying fiber reinforced composite material layers and wave-absorbing material layers in a mould, and carrying out hot pressing at 100-150 ℃ for 1-3h to obtain a stealth bulletproof layer;

step two preparation of stealth bulletproof plate

Arranging the glass fiber reinforced plastic plate layer, the stealth bulletproof layer and the carbon fiber composite material layer from top to bottom, bonding the glass fiber reinforced plastic plate layer, the stealth bulletproof layer and the carbon fiber composite material layer by using epoxy resin, and then pressing the glass fiber reinforced plastic plate layer, the stealth bulletproof layer and the carbon fiber composite material layer at the temperature of 40-100 ℃ for 60-120 min to obtain the stealth bulletproof plate with an integrated structure.

Technical Field

The invention belongs to the technical field of stealth bulletproof, and particularly relates to a broadband and efficient wave-absorbing stealth bulletproof plate with an integrated structure and a preparation method thereof.

Background

The present world military science and technology develops rapidly, reconnaissance and striking capability also develops rapidly, and stealth bulletproof materials are produced in order to improve the battlefield viability of weaponry. The stealth bulletproof material has the dual functions of radar stealth and bulletproof, but the traditional stealth bulletproof material is mainly formed by combining a radar absorbing material and a bulletproof material which are separated in function, so that the stealth bulletproof material is thicker in thickness and large in surface density, and the requirements of the traditional weaponry on the thin stealth bulletproof material and light weight are difficult to meet.

Disclosure of Invention

Aiming at the defects of thick thickness and large weight of stealth bulletproof materials in the prior art, the invention aims to provide the stealth bulletproof plate with an integrated structure, which has the advantages of thin thickness, light weight, wide wave-absorbing frequency band and radar stealth and bulletproof functions, and the preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme,

the wave-absorbing stealth bulletproof plate with an integrated structure comprises a glass fiber reinforced plastic plate layer, a stealth bulletproof layer and a carbon fiber composite material layer from outside to inside in sequence; the stealth bulletproof layer is obtained by alternately laminating fiber reinforced composite material layers and wave-absorbing material layers, the fiber reinforced composite material in the fiber reinforced composite material layers is an ultrahigh molecular weight polyethylene fiber reinforced polyethylene-based composite material or an aramid fiber epoxy resin-based composite material, and the thickness of the stealth bulletproof layer is less than or equal to 23 mm.

In the present invention, the ultra-high molecular weight in the ultra-high molecular weight polyethylene fiber reinforced polyethylene-based composite material means a molecular weight of more than 300 ten thousand. The carbon fiber composite material in the carbon fiber composite material layer is a carbon fiber reinforced resin matrix composite material which is used as a reflecting layer of the stealth bulletproof plate.

Preferably, the composite material in the fiber reinforced composite material layer is an ultrahigh molecular weight polyethylene fiber reinforced polyethylene-based composite material.

In the preferable scheme, the thickness of the glass fiber reinforced plastic plate layer is 0.3-2 mm, the thickness of the stealth bulletproof layer is 18-22 mm, and the thickness of the carbon fiber composite material layer is 0.1-1 mm.

In the preferable scheme, in the stealth bulletproof layer, the bottommost layer and the topmost layer are both fiber reinforced composite material layers and comprise 2-6 fiber reinforced composite material layers and 1-5 wave-absorbing material layers, the thickness of any one fiber reinforced composite material layer is 1-8 mm, and the thickness of any one wave-absorbing material layer is 0.01-0.5 mm.

In the preferable scheme, in the stealth bulletproof layer, the thickness of the fiber reinforced composite material layer of the (N + 1) th layer is more than or equal to that of the fiber reinforced composite material layer of the Nth layer.

In the preferable scheme, the surface density of the stealth bulletproof plate is less than or equal to 23Kg/m²。

In a preferable scheme, the wave-absorbing material layer is at least one selected from a resistance film, an iron coating carbon fiber magnetic material film and a metamaterial film.

Preferably, the wave-absorbing material layer is composed of a resistance film, an iron coating carbon fiber magnetic material film and a metamaterial film. The inventor finds that when the wave-absorbing material layer is provided with the three films, the finally obtained wave-absorbing stealth bulletproof plate has the optimal performance.

In the invention, the resistance film is directly commercially available in the prior art, and can be selected from one of PE, PU and ITO conductive films according to different manufacturers.

The metamaterial thin film is directly commercially available in the prior art.

Further preferably, the preparation process of the iron-coated carbon fiber magnetic material film comprises the following steps: spraying a layer of epoxy glue on the release film, uniformly dispersing the carbon fiber with the pyrolytic carbonyl iron coating on the epoxy glue, and curing at normal temperature to obtain the carbon fiber release film;

the preparation method of the carbon fiber with the pyrolytic carbonyl iron coating comprises the following steps: dispersing the pretreated carbon fiber in xylene to obtain a solution containing carbon fiber, then adding carbonyl iron to obtain slurry, carrying out pyrolysis reaction under a protective atmosphere, carrying out solid-liquid separation, cleaning the obtained solid phase, soaking the solid phase in a mixed solution containing a coupling agent, and drying to obtain the coated carbon fiber.

Further preferably, the carbon fiber is cut into 30-40 cm, then is subjected to heat treatment at 400-600 ℃ for 40-50 min, and then is cut into 2-5 mm; and drying to obtain the pretreated carbon fiber.

Further preferably, the drying temperature is 75-85 ℃, and the drying time is 10-12 h.

In the actual operation process, after the carbon fiber is cut into 30-40 cm, two ends of the carbon fiber are knotted, and then the knotted fiber is put into a tube furnace for heat treatment.

More preferably, the mass ratio of the carbon fiber to the xylene is 0.5: 9-15.

Further preferably, the carbon fibers are dispersed in the organic solvent under stirring, the stirring speed is 800-2000 r/min, and the stirring time is 10-30 min.

By stirring at such a high speed, the carbon fibers can be sufficiently dispersed in the organic solvent, thereby ensuring the uniformity of the coating.

In the actual operation process, the high-speed stirring of a dispersing machine is adopted to realize the dispersion of the carbon fibers in the organic solvent.

More preferably, the mass ratio of the carbon fibers to the carbonyl iron is 0.5: 1-3. Controlling the hydroxyl iron in the range can ensure that the whole carbon fiber is evenly coated with the iron coating, and can ensure that the hydroxyl can be completely decomposed.

Still further preferably, the procedure of the pyrolysis reaction is: the temperature is raised to 90-110 ℃ from normal temperature for 40-80 min, then raised to 120-140 ℃ for 300-420 min, then raised to 150-160 ℃ for 2000-3000 min, and kept at 150-160 ℃ for 2000-3000 min, and then lowered to normal temperature for 60-180 min.

The inventor finds that the iron coating can be uniformly coated on the carbon fiber by controlling the pyrolysis procedure within the preferable range, and if the procedure is not carried out, if the early temperature is too high and the temperature is too high, the hydroxyl iron is decomposed too fast, and micro-nano accumulation is caused, so that the coating is not uniform.

Further preferably, the pyrolysis reaction is carried out under stirring, wherein the stirring mode is that the stirring is carried out for 1-2 min at the rotating speed of 30-60 r/min, and then the stirring is carried out for 1-5 min at the rotating speed of 20-30 r/min at intervals of 1-2 h. In the intermittent stirring manner adopted by the invention, the inventor finds that the final coating can be uniform by the stirring manner, and if continuous stirring is adopted or the stirring speed is too high, carbon fibers are agglomerated, so that the coating is not uniform.

More preferably, the solid phase is washed with absolute ethanol 3 times or more.

More preferably, in the mixed solution containing the coupling agent, the coupling agent is KH550, and the mass fraction of the coupling agent is 0.3-0.6 wt%.

More preferably, in the mixed solution containing the coupling agent, the solvent is an ethanol aqueous solution, and the mass fraction of ethanol in the ethanol aqueous solution is 90-95 wt%.

Further preferably, the soaking is carried out under stirring, and the soaking time is 30-60 min

Preferably, the drying process comprises the steps of spreading for 10-12 hours at room temperature, and then drying for 10-20 hours at 40-60 ℃.

The invention discloses a preparation method of a stealth bulletproof plate with an integrated structure, which comprises the following steps: the method comprises the following steps:

step one preparation of stealth bulletproof layer

Alternately stacking and laying fiber reinforced composite material layers and wave-absorbing material layers in a mould, and carrying out hot pressing at 100-150 ℃ for 1-3h to obtain a stealth bulletproof layer;

step two preparation of stealth bulletproof plate

Arranging the glass fiber reinforced plastic plate layer, the stealth bulletproof layer and the carbon fiber composite material layer from top to bottom, bonding the glass fiber reinforced plastic plate layer, the stealth bulletproof layer and the carbon fiber composite material layer by using epoxy resin, and then pressing the glass fiber reinforced plastic plate layer, the stealth bulletproof layer and the carbon fiber composite material layer at the temperature of 40-100 ℃ for 60-120 min to obtain the stealth bulletproof plate with an integrated structure.

In the actual operation process, the solidified invisible bulletproof plate with the integrated structure is cut according to the requirements of products, and masking tapes (paper tapes) are used for sticking the four peripheries of the upper surface and the lower surface to be flush with corners. Filling and leveling the groove by using edge sealing glue, sealing the edge, and curing at normal temperature for 20-24h to obtain a finished product of the stealth bulletproof plate.

The invention provides a broadband and efficient wave-absorbing stealth bulletproof plate with an integrated structure, which adopts a function and structure integrated design and effectively improves radar stealth and bulletproof performance on the basis of meeting national standards. The invention adopts the carbon fiber composite material as the reflecting layer, not only can reflect the transmitted electromagnetic waves into the stealth bulletproof layer, but also can effectively improve the defects of poor bonding property and easy delamination of the stealth bulletproof plate. The glass fiber reinforced plastic plate is used as the panel layer, so that the stealth bulletproof layer can be effectively protected, the stealth bulletproof layer can be effectively protected while the glass fiber reinforced plastic plate has good wave permeability, and the influence of the external environment on the stealth bulletproof layer is reduced. In addition, the edges of the periphery of the stealth bulletproof plate are sealed, so that the interior stealth bulletproof layer can be effectively protected, and the influence of external factors on the stealth bulletproof layer is avoided.

In the preferred scheme of the invention, the wave-absorbing material layer is formed by alternately laminating ultrahigh molecular weight polyethylene fiber reinforced polyethylene-based composite materials and wave-absorbing materials, wherein an iron coating carbon fiber magnetic material film is introduced into the wave-absorbing material layer, and the carbon fiber has higher specific strength and specific modulus, and also has excellent performances in conductivity, reflection and absorption, electromagnetic shielding and electronic countermeasure, and is an ideal wave-absorbing material with double functions of mechanical bearing and radar wave reflection section reduction.

In a preferred scheme of the invention, the stealth bulletproof plate can defend 7.62mm common steel core bullets from being shot vertically at a distance of 100m without breakdown. The radar reflectivity of the frequency 1-2GHz is less than-8 dB, the radar reflectivity of the frequency 2-4GHz and the radar reflectivity of the frequency 4-8GHz are less than-13 dB, the radar reflectivity mean values of the frequency 8-12GHz, the frequency 12-18GHz and the radar reflectivity mean values of the frequency 26.5-40GHz are all less than-18 dB, and the wave absorbing effect is excellent.

Drawings

Fig. 1 is a schematic structural view of a stealth bulletproof plate.

In the attached drawing, the composite bulletproof energy-saving building material comprises a glass fiber reinforced plastic plate layer 1, a glass fiber reinforced plastic plate layer 2, a carbon fiber composite material layer 3 and a stealth bulletproof layer, wherein the materials 4, 6, 8, 10 and 12 are all fiber reinforced composite material layers, and the materials 5, 7, 9 and 11 are wave-absorbing material layers.

Detailed Description

The following examples are intended to further illustrate the present disclosure, but not to limit the scope of the invention.

As used in the examples of the present invention, the resistive film was an ITO conductive film obtained from Dongguan volitake optical materials, Inc

The metamaterial thin film is purchased from Shenzhen light launch Innovation technology, Inc.

Example 1:

the preparation method of the integrated stealth bulletproof plate comprises the following steps:

preparing a stealth bulletproof layer: an ultrahigh molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 3.0mm, an ultrahigh molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 0.02mm and the thickness of 4.0mm, an ultrahigh molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 0.02mm and the thickness of 4.9mm, an ultrahigh molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 0.02mm and the thickness of 5.5mm, an ultrahigh molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 0.02mm and the thickness of 5.9mm are sequentially laid in a mould, and a stealth bulletproof layer is formed by hot pressing at 100 ℃ for 2 hours.

Preparing a stealth bulletproof plate: and (3) bonding the stealth bulletproof layer, the 0.6mm glass fiber reinforced plastic plate layer and the 0.4mm carbon fiber composite material (carbon fiber reinforced resin matrix composite material) layer from top to bottom, pressing the bonded stealth bulletproof plate with the integrated structure at 70 ℃ for 60min, and taking out the stealth bulletproof plate with the integrated structure after pressing.

Edge sealing: after the panel was cured, it was cut 300 × 300mm, and the upper and lower surfaces were pasted around their peripheries using masking tape (paper tape) to be flush with the corners. And filling, leveling and sealing the groove by using a sealing adhesive. Curing at normal temperature for 20h to obtain the invisible bulletproof plate finished product with the integrated structure.

The surface density of the integrated stealth bulletproof plate prepared by the embodiment is 23Kg/m²And the steel core can prevent the puncture of 7.62mm common steel core bullets when vertically shot at a distance of 100 m. The radar reflectivity of 1-2GHz is less than-8 dB, the radar reflectivity of 2-4GHz, 4-8GHz and 8-12GHz are less than-13 dB, and the radar reflectivity of the radar at the frequencies of 12-18GHz and 26.5-40GHzThe mean values are all less than-16 dB.

Example 2:

the preparation method of the integrated stealth bulletproof plate comprises the following steps:

preparing a stealth bulletproof layer: aramid fiber epoxy resin-based composite materials with the thickness of 3.2mm, aramid fiber epoxy resin-based composite materials with the thickness of 0.02mm and the thickness of 3.4mm, aramid fiber epoxy resin-based composite materials with the thickness of 0.3mm and aramid fiber epoxy resin-based composite materials with the thickness of 3.6mm are sequentially paved in a mould, and the stealth bulletproof layer is formed by hot-pressing at the temperature of 80 ℃.

Preparing a stealth bulletproof plate: and (3) bonding the stealth bulletproof layer, the 0.4mm glass fiber reinforced plastic plate layer and the 0.2mm carbon fiber composite material layer from top to bottom, pressing the bonded stealth bulletproof plate with the integrated structure at 70 ℃, wherein the pressing time is 60min, and taking out the stealth bulletproof plate with the integrated structure after pressing.

Edge sealing: after the panel was cured, it was cut 300 × 300mm, and the upper and lower surfaces were pasted around their peripheries using masking tape (paper tape) to be flush with the corners. And filling, leveling and sealing the groove by using a sealing adhesive. Curing at normal temperature for 20h to obtain the invisible bulletproof plate finished product with the integrated structure.

The surface density of the integrated stealth bulletproof plate prepared by the embodiment is 11Kg/m³The bulletproof performance is equivalent to that of a 5mm bulletproof steel plate, the wave absorbing performance meets the requirement that the radar reflectivity is less than-13 dB within the frequency ranges of 2-18GHz and 26.5-40GHz, and the wave absorbing effect is good.

Example 3

The iron-coated carbon fiber magnetic material film is prepared as follows:

s1, cutting carbon fibers into 30cm long, knotting two ends of the carbon fibers, putting the knotted fibers into a tube furnace, firing at a high temperature of 500 ℃ for 40min, cooling and taking out; cutting into short carbon fibers;

s2, drying the carbon fiber at 80 ℃ for 10 h;

s3, sealing the reaction kettle, adding about 2/3 of solvent into 6 gas washing bottles, introducing nitrogen, and testing whether the reaction kettle cover leaks gas or not by using soap water, wherein no bubbles exist, and the reaction kettle is sealed to be qualified.

S4 carbon fiber 500g and solvent xylene 12kg are added into a barrel and dispersed by a dispersion machine at high speed of 800 r/min for 30 min.

S5, adding the well dispersed xylene fiber soak solution into a reaction kettle; weighing a certain amount of iron pentacarbonyl, filling the iron pentacarbonyl into a reaction kettle, and flushing a carbonyl iron container and a funnel by using the retained dimethylbenzene; and rapidly sealing the reaction kettle, introducing nitrogen, continuing for 30min, igniting by using a lighter, observing whether the flame is immediately extinguished at an air outlet, wherein the flame is immediately extinguished to indicate that the air in the reaction kettle is replaced by the nitrogen.

The temperature-raising program set for the S6 reaction kettle is as follows: the temperature is raised to 100 ℃ from normal temperature within 60min, then raised to 130 ℃ within 360min, then raised to 155 ℃ within 2400min, and kept at 155 ℃ for 2400min, and then lowered to normal temperature within 60 min. 88 hours in total

S7, starting stirring at 30r/min for 2min, and then stirring at 20r/min for 1min every 1 h;

s8, setting parameters of the water cooler to be-2 ℃, opening a water outlet valve of the water cooler, and starting the water cooler.

And cooling the S9 reaction kettle to room temperature, closing the nitrogen valve, and closing the water outlet valves of the water cooler and the water chiller. And slowly opening a blanking valve to avoid liquid splashing and xylene discharging, taking out the solid fiber from the upper part, and filtering by using a 80-mesh screen.

S10, cleaning the plated fiber for 3 times by using absolute ethyl alcohol; performing post-treatment with 95% ethanol and 0.4 wt% KH550 mixed solution of coupling agent, soaking for 30min under stirring, and filtering.

And S11, tedding at room temperature for 10 hours, and drying in an oven at a low temperature of 40 ℃ for 10 hours to obtain the carbonyl iron coating carbon fiber magnetic wave-absorbing composite material.

S12, preparing the iron-coated carbon fiber into an iron-coated carbon fiber magnetic material film: firstly, uniformly spraying a layer of epoxy glue on a release film, then uniformly dispersing an iron coating carbon fiber magnetic material film on the sprayed glue, and curing at normal temperature to form the film.

A preparation method of an integrated stealth bulletproof plate comprises the following steps:

preparing a stealth bulletproof layer: an ultra-high molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 3.7mm, an ultra-high molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 0.02mm and 3.7mm as a resistance film, an ultra-high molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 3.7mm, an iron coating carbon fiber magnetic material film of a third wave absorbing material layer with the thickness of 0.02mm, an ultra-high molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 5.5mm, an ultra-high molecular weight polyethylene fiber reinforced polyethylene based composite material with the thickness of 0.1mm and 5.5mm as a metamaterial film of a fourth wave absorbing material layer are sequentially laid in a mould, and the stealth bulletproof layer is formed by hot pressing for.

Preparing a stealth bulletproof plate: and (3) bonding the stealth bulletproof layer, the 0.6mm glass fiber reinforced plastic plate layer and the 0.2mm carbon fiber composite material layer from top to bottom, pressing the bonded stealth bulletproof plate with the integrated structure at 90 ℃, wherein the pressing time is 90min, and taking out the stealth bulletproof plate with the integrated structure after pressing.

Edge sealing: after the panel was cured, it was cut 300 × 300mm, and the upper and lower surfaces were pasted around their peripheries using masking tape (paper tape) to be flush with the corners. And filling, leveling and sealing the groove by using a sealing adhesive. Curing at normal temperature for 24h to obtain the invisible bulletproof plate finished product with the integrated structure.

The surface density of the integrated stealth bulletproof plate prepared by the embodiment is 22Kg/m²And the steel core can prevent the puncture of 7.62mm common steel core bullets when vertically shot at a distance of 100 m. The radar reflectivity of 1-2GHz is less than-8 dB, the radar reflectivity of 2-4GHz and 4-8GHz are both less than-13 dB, and the radar reflectivity mean values of 8-12GHz, 12-18GHz and 26.5-40GHz are all less than-18 dB.

Comparative example 1

The other conditions are the same as those in the example 3, and only in the preparation process of the iron-coated carbon fiber magnetic material film, the stirring mode is different, in the comparative example, the stirring mode is that the stirring is continuously carried out at the rotating speed of 30-60 r/min, after solid-liquid separation, carbon fiber agglomeration is found, and after cleaning and drying, no coating is formed inside, so that the coating is not uniform.

Comparative example 2

The other conditions are the same as those of the example 3, only in the process of preparing the iron-coated carbon fiber magnetic material film, the temperature program is set differently, the temperature program set in the comparative example 2 is firstly heated from the normal temperature to 100 ℃ through 60min, then heated to 130 ℃ through 90min, then heated to 155 ℃ through 1200min, and then kept at 3600min at 155 ℃, and then cooled to the normal temperature through 60 min. In 88 hours total, after the solid-liquid separation, it was found that iron powder was accumulated on the surface of some carbon fibers and in the container to cause non-uniform coating.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and those skilled in the art can make many similar changes without departing from the principle of the present invention and the claims, and these changes are all within the scope of the present invention.