Composite flexible plate with bulletproof performance and high flexibility and preparation method thereof

Abstract

The invention provides a composite flexible plate with bulletproof performance and high flexibility and a preparation method thereof, and relates to the technical field of materials. The composite flexible plate with bulletproof performance and high flexibility is prepared by stacking and paving multiple layers of single-layer prepregs and then carrying out hot press molding. Wherein the single-layer prepreg is formed by compounding an aramid fabric and a modified rubber film covering at least one surface of the aramid fabric. The modified rubber film melts, flows and adheres to the adjacent single-layer prepreg in the hot pressing process, so that the composite flexible plate has the bulletproof performance and meanwhile keeps the characteristic of being capable of being bent at will.

Description

Technical Field

[0001] This invention provides a composite flexible plate with both ballistic protection and high flexibility, and its preparation method, belonging to the field of materials technology. Background Technology

[0002] Aramid fibers are widely used in the preparation of bulletproof materials due to their excellent mechanical and heat resistance properties. For example, Chinese patent CN110861382A discloses a solvent-free aramid bulletproof prepreg and its composite material. This technology uses modified epoxy resin and a hot-melt fiber carrier to form an adhesive film, and one side of the adhesive film is impregnated with aramid fabric. The resulting composite material has good bulletproof performance. However, the epoxy resin matrix used in this technology forms a rigid network structure after curing, resulting in insufficient flexibility of the composite material, which cannot be bent arbitrarily. Chinese patent CN105856789A discloses a method for preparing a bulletproof aramid composite material, which involves stacking aramid plain weave prepreg and aramid twill weave prepreg in a specific manner and then hot-pressing them together to reduce the number of layers and thus reduce weight. Although this method improves the bulletproof performance of the material to some extent, the resin matrix used still limits the flexibility of the material.

[0003] Chinese patent CN112549693A discloses an impact-resistant composite material, consisting of a prepreg layer, a fabric layer, and a thermoplastic material or thermoplastic composite material, formed by integral composite molding. While this technology utilizes thermoplastic materials to improve the material's toughness, the complex multi-layered structure increases manufacturing difficulty, and the overall flexibility of the material remains limited. Chinese patent CN104215130B discloses a multifunctional composite bulletproof plate and its preparation method. This bulletproof plate includes a rigid reinforcement layer, an intermediate bulletproof layer, an anti-back convexity layer, and a buffer layer. This technology integrates multiple functions through a multi-layered structure design; however, due to the use of thermosetting resin as the matrix material, the resulting bulletproof plate has high rigidity and insufficient flexibility.

[0004] Chinese patent CN102909920B discloses a modified phenolic resin semi-impregnated aramid fiber prepreg. By controlling the resin impregnation rate between 5% and 20%, the resulting aramid elastic composite material exhibits low porosity and high structural strength. However, the network structure formed after the phenolic resin cures still results in insufficient flexibility in the material, preventing arbitrary bending.

[0005] In summary, existing bulletproof materials generally suffer from the following problems: On the one hand, while traditional rigid bulletproof plates possess good ballistic protection performance, they lack flexibility and cannot be used on curved surfaces without molds; on the other hand, while existing flexible bulletproof materials have a certain degree of flexibility, their ballistic protection performance is poor, failing to simultaneously meet the requirements of high ballistic protection and high flexibility. Furthermore, existing technologies struggle to achieve both good ballistic protection performance and the flexibility to be bent arbitrarily, which severely limits the application scope and effectiveness of bulletproof materials in practical applications. Therefore, developing a composite flexible plate that combines excellent ballistic protection performance and high flexibility has significant practical value and market demand. Summary of the Invention

[0006] In order to solve the technical problem that existing bulletproof materials cannot simultaneously achieve both bulletproof performance and flexibility, and to achieve the technical effect of having both excellent bulletproof performance and high flexibility, this invention provides a composite flexible plate with both bulletproof performance and high flexibility and its preparation method.

[0007] The present invention is specifically implemented using the following technical solutions: A method for preparing a composite flexible plate that combines ballistic protection and high flexibility includes the following steps: (1) Provide aramid fabrics and modified rubber films; (2) The modified rubber film is covered on at least one surface of the aramid fabric to form a single-layer prepreg; (3) The single-layer prepreg is stacked in multiple layers to obtain a multi-layer structure; (4) The multi-layered structure after stacking is subjected to hot pressing treatment, and after cooling, the composite flexible board is obtained; In step (3), when the aramid fibers in the single-layer prepreg of adjacent layers are laid, the fiber orientations are 0°, ±45° or 90°.

[0008] Preferably, the aramid fabric in step (1) is aramid woven fabric or aramid non-woven fabric.

[0009] Preferably, the modified rubber film in step (1) is a modified butyl rubber film or a modified polyisoprene rubber film.

[0010] Preferably, the modified rubber film in step (2) covers one or both sides of the aramid fabric.

[0011] Preferably, the multilayer structure in step (3) has 2-40 layers.

[0012] Preferably, during step (3) of the stacking process, the fiber orientation of the aramid woven fabric in the single-layer prepreg of the adjacent layers is arranged in a cross pattern of 0° / 90° or +45° / -45°, and the fiber orientation of the aramid non-woven fabric in the single-layer prepreg of the adjacent layers is arranged in a cross pattern of 0° / 90°.

[0013] Preferably, the temperature of hot pressing in step (4) is 50℃-180℃, the pressure is 0.5-10 MPa, and the hot pressing time is 5-20 minutes.

[0014] The present invention also provides a composite flexible plate with both ballistic performance and high flexibility, with a size of 50cm*50cm; when bent by 20mm, the pressure value of the composite flexible plate is no greater than 180N.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The composite flexible plate prepared by this invention has both excellent ballistic performance and high flexibility. It can be bent at will and can adapt to curved surface requirements, expanding the application of curved surfaces in the absence of molds. It overcomes the shortcomings of traditional rigid ballistic plates, which are too rigid and cannot flexibly fit curved surfaces. The modified rubber film of this invention can melt and flow during hot pressing and bond adjacent layers of aramid fabric to form an integral structure, thereby improving the overall performance of the material and solving the problem of poor ballistic performance of existing flexible bulletproof materials. This invention achieves an organic combination of high-strength and flexible materials through a composite structure of aramid fabric and modified rubber film, overcoming the shortcomings of traditional bulletproof materials that are too rigid or have insufficient protective performance. The fiber orientation of adjacent aramid fabric layers in this invention is cross-arranged, which can optimize the ballistic performance and mechanical properties, and improve the overall protective effect of the material. The preparation process of this invention is simple, highly controllable, easy to industrialize, saves mold costs, reduces production costs, and improves the market competitiveness of the product. Detailed Implementation

[0016] The technical solution of the present invention will be clearly and completely described below with the aid of embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example 1

[0018] A composite flexible board combining ballistic performance and high flexibility is produced by hot pressing multiple layers of single-layer prepreg. Each single-layer prepreg is composed of aramid fabric and a modified butyl rubber film covering at least one surface. During hot pressing, the modified butyl rubber film melts and flows, bonding adjacent layers of single-layer prepreg, allowing the composite flexible board to maintain its bendability while possessing ballistic performance.

[0019] In this embodiment, the modified butyl rubber film in the single-layer prepreg covers both sides of the aramid fabric. Specifically, the modified butyl rubber film is bonded to both sides of the aramid fabric to form a three-layer structure of the single-layer prepreg, namely, a structure of "modified butyl rubber film - aramid fabric - modified butyl rubber film". This double-sided covering structure allows the aramid fabric to fully bond with the modified butyl rubber film, improving the overall performance of the composite flexible board.

[0020] During the stacking process, the aramid fibers in the adjacent single-layer prepregs are arranged in a 0° / 90° cross pattern. Specifically, the aramid fiber orientation in the first single-layer prepreg is defined as 0°, the aramid fiber orientation in the second single-layer prepreg is 90°, the aramid fiber orientation in the third single-layer prepreg is 0° again, and so on. This cross-arrangement allows the composite flexible panel to have good mechanical properties in different directions, improving bulletproof performance.

[0021] In this embodiment, the number of layers of multilayer single-layer prepreg is 10. This layer design ensures that the composite flexible board has sufficient ballistic performance without making the board too thick, which would affect its flexibility and ease of use.

[0022] Aramid fabrics are made from woven aramid fibers, a material with excellent tensile strength and impact resistance, making it an ideal choice for producing bulletproof materials. The areal density of woven aramid fabric is 200 g / m². 2 With a thickness of 0.25mm, this specification of aramid fabric provides sufficient ballistic protection without making the final product too heavy.

[0023] The modified butyl rubber film uses brominated butyl rubber film with a thickness of 0.2 mm. The brominated butyl rubber film has good adhesion and flexibility, and can fully melt and flow during hot pressing to effectively bond adjacent layers of aramid fabric while maintaining the flexibility of the molded product.

[0024] The hot-pressing process parameters are: temperature 80℃, pressure 5MPa, and time 10 minutes. Under these conditions, the modified butyl rubber film can fully melt and penetrate into the aramid fabric, forming a strong adhesive interface without damaging the aramid fibers.

[0025] The method for preparing the composite flexible plate of the present invention includes the following steps: Firstly, aramid woven fabric and brominated butyl rubber film are provided as raw materials. The areal density of the aramid woven fabric is 200 g / m². 2 The thickness is 0.25 mm; the thickness of the brominated butyl rubber film is 0.03 mm.

[0026] A brominated butyl rubber film is applied to both sides of the aramid woven fabric, and then gently pressed to initially bond them together, forming a single-layer prepreg. Specifically, one brominated butyl rubber film is first laid flat on a smooth work surface, then the aramid woven fabric is placed on the rubber film. Another brominated butyl rubber film is then placed over the top surface of the aramid fabric. Finally, a hand roller is used to gently press the film, ensuring the three layers are tightly bonded to form a single-layer prepreg.

[0027] The prepared single-layer prepreg is then multi-layered according to design requirements. In this embodiment, 10 layers are stacked, with the aramid fibers of adjacent layers arranged in a 0° / 90° cross pattern. Specifically, the first layer of single-layer prepreg is placed on a flat release film, with the fiber direction defined as 0°; then the second layer of single-layer prepreg is placed on top of the first layer, with the fiber direction rotated 90°; and so on, until all 10 layers are stacked. During the stacking process, it is necessary to ensure that each layer is flat and adhered to the others, without obvious air bubbles or wrinkles.

[0028] The multilayered structure is then subjected to hot pressing. The stacked multilayered structure, along with the release liner, is placed in a hot press at a set temperature of 80°C, a pressure of 5 MPa, and a holding time of 10 minutes. During hot pressing, the brominated butyl rubber membrane melts and flows, penetrating into the interlayer of the aramid fabric and bonding adjacent layers. After hot pressing, the pressure is released, and the structure is allowed to cool naturally to room temperature (approximately 25°C).

[0029] The composite flexible board prepared by the above process has a thickness of approximately 6.5 mm and an areal density of approximately 10.2 kg / m³. 2 The composite flexible sheet has a smooth surface without obvious defects and can be bent arbitrarily without permanent deformation or delamination. Ballistic testing has verified that the composite flexible sheet can effectively resist the impact of 9mm caliber pistol bullets while maintaining good flexibility. It can be bent and fitted according to usage requirements, making it suitable for various occasions requiring both ballistic protection and flexibility.

[0030] Example 2

[0031] In this embodiment, the modified butyl rubber film in the single-layer prepreg covers one side of the aramid fabric. Specifically, the modified butyl rubber film is adhered to one side of the aramid fabric, forming a double-layer structure of the single-layer prepreg, namely, the "aramid fabric-modified butyl rubber film" structure. During stacking, the modified butyl rubber film side of the single-layer prepreg is arranged upwards, so that there is always a layer of modified butyl rubber film between adjacent layers. This single-sided covering structure can reduce material usage and lower production costs, while still ensuring good interlayer adhesion.

[0032] During the stacking process, the aramid fibers in the adjacent single-layer prepregs are arranged in a ±45° cross pattern. Specifically, the aramid fiber orientation in the first single-layer prepreg is defined as +45°, the second single-layer prepreg has a -45° orientation, the third single-layer prepreg has a +45° orientation, and so on. This ±45° cross arrangement enables the composite flexible panel to have better shear resistance under oblique stress, thus improving bulletproof performance.

[0033] In this embodiment, the number of layers of multilayer single-layer prepreg is 8. This layer design can make the composite flexible board thinner and lighter while ensuring ballistic performance and improving wearing comfort.

[0034] Aramid fabric is made of woven aramid fiber, a material with good heat resistance and chemical stability, while also possessing some ballistic protection. The areal density of woven aramid fiber is 200 g / m². 2 With a thickness of 0.25mm, this specification of aramid fabric provides adequate ballistic protection while maintaining good flexibility.

[0035] The rubber membrane is a modified butyl rubber membrane with a thickness of 0.3 mm. The modified butyl rubber membrane has better adhesion properties and can achieve good melt flow at lower temperatures, which is beneficial to improving the interlayer bonding strength of the composite flexible board without affecting its flexibility.

[0036] The hot pressing process parameters are: temperature 80℃, pressure 10MPa, and time 15 minutes. This process ensures sufficient melt flow and good interlayer adhesion, while avoiding thermal damage to the aramid fibers.

[0037] The method for preparing the composite flexible plate of the present invention includes the following steps: Firstly, aramid woven fabric and modified butyl rubber film are provided as raw materials. The areal density of the aramid woven fabric is 200 g / m². 2 The thickness is 0.25mm.

[0038] A modified butyl rubber film is applied to one side of an aramid woven fabric, and then gently pressed to allow for initial adhesion, forming a single-layer prepreg. Specifically, the aramid woven fabric is laid flat on a workbench, and the modified butyl rubber film is then placed over the upper surface of the aramid fabric. A hand roller is used to gently press the film, ensuring a tight bond between the two layers to form a single-layer prepreg.

[0039] The prepared single-layer prepreg is then multi-layered according to design requirements. In this embodiment, eight layers are stacked, with the aramid fibers of adjacent layers arranged at ±45° angles. Specifically, the first layer of single-layer prepreg is placed on a flat release liner with the rubber film side facing up and the fiber direction defined as +45°; then the second layer of single-layer prepreg is placed on top of the first layer with the rubber film side facing up and the fiber direction defined as -45°; and so on, until all eight layers are stacked. During the stacking process, it is necessary to ensure that each layer is flat and adhered to the other layers, without obvious air bubbles or wrinkles.

[0040] The multilayered structure after stacking is subjected to hot pressing. The stacked multilayered structure, along with the release liner, is placed in a hot press. The temperature is set to 80℃, the pressure to 10MPa, and the holding time to 15 minutes. During the hot pressing process, the butyl rubber film with added tackifying resin melts and flows, penetrating into the spaces between the aramid fabric layers and bonding adjacent layers. After hot pressing, the pressure is released, and the structure is removed and allowed to cool naturally to room temperature (approximately 25℃).

[0041] The composite flexible board prepared by the above process has a thickness of approximately 3.8 mm and an areal density of approximately 6.5 kg / m³. 2 The composite flexible sheet has a smooth surface without obvious defects and can be bent arbitrarily without permanent deformation or delamination. Ballistic testing has verified that the composite flexible sheet can effectively resist the impact of 9mm pistol bullets while maintaining good flexibility. It can be bent and fitted according to usage requirements, making it suitable for ballistic protection applications requiring high flexibility.

[0042] Example 3

[0043] In this embodiment, the modified polyisoprene rubber film in the single-layer prepreg covers both sides of the aramid fabric. Specifically, the modified polyisoprene rubber film is bonded to both sides of the aramid fabric, forming a three-layer structure of the single-layer prepreg, namely, a structure of "modified polyisoprene rubber film - aramid fabric - modified polyisoprene rubber film". This double-sided covering structure allows the aramid fabric to fully bond with the modified polyisoprene rubber film, improving the overall performance of the composite flexible board.

[0044] During the stacking process, the aramid fibers in the adjacent single-layer prepregs are arranged in a 0° / 90° cross pattern. Specifically, the aramid fiber orientation in the first single-layer prepreg is defined as 0°, the aramid fiber orientation in the second single-layer prepreg is 90°, the aramid fiber orientation in the third single-layer prepreg is 0° again, and so on. This cross-arrangement allows the composite flexible panel to have good mechanical properties in different directions, improving bulletproof performance.

[0045] In this embodiment, the multilayer single-layer prepreg is stacked in 16 layers. This higher layer count provides a higher level of ballistic protection and is suitable for applications requiring a higher level of protection.

[0046] Aramid fabrics are made from non-woven aramid fibers, a material with excellent tensile strength and impact resistance, making it an ideal choice for preparing bulletproof materials. The areal density of para-aramid non-woven fabric is 210 g / m³. 2 With a thickness of 0.15mm, this specification of aramid fabric can provide higher ballistic performance.

[0047] The modified polyisoprene rubber film has a thickness of 0.18 mm, exhibiting good weather resistance and abrasion resistance while maintaining good adhesion and flexibility. It can fully melt and flow during hot pressing, effectively bonding adjacent layers of aramid fabric.

[0048] The hot-pressing process parameters are: temperature 70℃, pressure 8MPa, and time 10 minutes. Under these conditions, the polyisoprene rubber film can quickly melt and penetrate into the aramid fabric, forming a strong adhesive interface and shortening the production cycle.

[0049] The method for preparing the composite flexible plate of the present invention includes the following steps: First, aramid nonwoven fabric and polyisoprene rubber film are provided as raw materials. The areal density of the aramid nonwoven fabric is 210 g / m². 2 The thickness is 0.15mm; the thickness of the polyisoprene rubber film is 0.18mm.

[0050] A polyisoprene rubber film is applied to both sides of an aramid nonwoven fabric, and then gently pressed to initially bond them together, forming a single-layer prepreg. Specifically, one piece of polyisoprene rubber film is first laid flat on a smooth work surface. Then, the aramid nonwoven fabric is placed on the rubber film, followed by another piece of polyisoprene rubber film covering the upper surface of the aramid fabric. Finally, a hand roller is used to gently press the film, ensuring the three layers are tightly bonded to form a single-layer prepreg.

[0051] The prepared single-layer prepreg is then multi-layered according to design requirements. In this embodiment, 16 layers are laid, with the aramid fibers of adjacent layers arranged in a 0° / 90° cross pattern. Specifically, the first layer of single-layer prepreg is placed on a flat release film, with the fiber direction defined as 0°; then the second layer of single-layer prepreg is placed on top of the first layer, with the fiber direction rotated 90°; and so on, until all 16 layers are laid. During the laying process, it is necessary to ensure that each layer is flat and adhered to the others, without obvious air bubbles or wrinkles.

[0052] The multilayered structure after stacking is subjected to hot pressing. The stacked multilayered structure, along with the release liner, is placed in a hot press. The temperature is set to 70℃, the pressure to 8MPa, and the holding time to 10 minutes. During the hot pressing process, the polyisoprene rubber film melts and flows, penetrating into the interlayer of the aramid fabric and bonding adjacent layers. After hot pressing is completed, the pressure is released, and the structure is allowed to cool naturally to room temperature (approximately 25℃).

[0053] The composite flexible board prepared by the above process has a thickness of approximately 5.0 mm and an areal density of approximately 4.9 kg / m³. 2 The composite flexible sheet has a smooth surface without obvious defects and can be bent arbitrarily without permanent deformation or delamination. Ballistic testing has verified that this composite flexible sheet can effectively resist the impact of high-powered ammunition, such as .44 Magnum pistol rounds, while maintaining good flexibility. It can be bent and fitted according to usage requirements, making it suitable for applications requiring a high level of protection.

[0054] It should be noted that Examples 1, 2, and 3 are all types of composite flexible boards that combine ballistic performance and high flexibility.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite flexible plate that combines ballistic performance and high flexibility, characterized in that, Includes the following steps: (1) Provide aramid fabrics and modified rubber films; (2) The modified rubber film is covered on at least one surface of the aramid fabric to form a single-layer prepreg; (3) The single-layer prepreg is stacked in multiple layers to obtain a multi-layer structure; (4) The multi-layered structure after stacking is subjected to hot pressing treatment, and after cooling, the composite flexible board is obtained; In step (3), when the aramid fibers in the single-layer prepreg of adjacent layers are laid, the fiber orientations are 0°, ±45° or 90°.

2. The method for preparing the composite flexible plate with both ballistic protection and high flexibility as described in claim 1, characterized in that, The aramid fabric mentioned in step (1) is aramid woven fabric or aramid non-woven fabric.

3. The method for preparing the composite flexible plate with both ballistic protection and high flexibility as described in claim 1, characterized in that, The modified rubber membrane in step (1) is a modified butyl rubber membrane or a modified polyisoprene rubber membrane with a thickness of less than 0.5 mm.

4. The method for preparing the composite flexible plate with both ballistic protection and high flexibility as described in claim 1, characterized in that, In step (2), the modified rubber film is applied to one or both sides of the aramid fabric.

5. The method for preparing the composite flexible plate with both ballistic protection and high flexibility as described in claim 1, characterized in that, The multi-layer structure described in step (3) consists of 2-40 layers.

6. The method for preparing the composite flexible plate with both ballistic protection and high flexibility as described in claim 1, characterized in that, In step (3), when the prepregs of adjacent layers are stacked, the fiber orientation of the aramid woven fabric is 0° / 90° or +45° / -45°, and the fiber orientation of the aramid non-woven fabric in the prepregs of adjacent layers is 0° / 90°.

7. The method for preparing the composite flexible plate with both ballistic protection and high flexibility as described in claim 1, characterized in that, Step (4) The hot pressing temperature is 50℃-180℃, the pressure is 0.5-10 MPa, and the hot pressing time is 5-20 minutes.

8. A composite flexible board that combines ballistic performance and high flexibility, characterized in that, It is prepared using any one of the methods described in claims 1 to 7.

9. The composite flexible board with both ballistic protection and high flexibility as described in claim 8, characterized in that, The composite flexible plate has dimensions of 50cm*50cm; when bent by 20mm, the pressure value of the composite flexible plate is no greater than 180N.