A helmet made of a composite material and its preparation process

Abstract

The present invention provides a helmet made of composite materials and its preparation process, which relates to the technical field of helmet equipment; the helmet includes a helmet body, and the helmet body includes a composite fiber layer and a polymer layer arranged in sequence from outside to inside; wherein, the composite fiber layer includes several layers of ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepregs and several layers of carbon fiber prepregs, the polymer layer is injection molded from polymers with a variety of preferred combinations and mixed according to a certain mass fraction, and the two functional layers are formed through two processes and are organically combined into one. The present invention has excellent penetration resistance and collision energy absorption performance, and has a low areal density, light weight and strong protection ability.

Description

Technical Field

[0001] The present invention belongs to the technical field of helmet devices, and particularly relates to a helmet made of composite materials and a preparation process thereof. Background Art

[0002] In modern explosion-proof and emergency response tasks, with the impact of many cold weapons, such as knives, axes, hammers, air rifles, etc., the helmets of the original head protection equipment composed of a single polymer material are prone to fragmentation after being impacted; in order to achieve high protection, ordinary polymer helmets mostly adopt the method of increasing the thickness of the helmet body, which leads to a continuous increase in the weight of the helmet, affects the execution of tactical actions after wearing, and long-term wearing will cause cervical spine injuries to personnel. In addition, the helmets made of a single polymer material are susceptible to the action of external environmental factors such as light and heat, resulting in aging and a continuous decline in the protection efficiency. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a helmet made of composite materials and a preparation process thereof. By adopting fiber composite materials and modified polymer materials, and through designing corresponding preparation processes, the helmet made by organically combining the composite fiber materials and polymer materials can effectively improve the protection performance and weather resistance of the helmet, and further reduce the weight of the helmet and improve the wearing comfort of the helmet.

[0004] On the one hand, the invention provides a helmet made of composite materials, including a helmet body. The helmet body includes a composite fiber layer and a polymer layer which are sequentially laminated from outside to inside; the composite fiber layer formed by hot pressing is placed in an injection mold, and the polymer layer is formed by injection molding, so that the polymer layer is placed on the composite fiber layer to form the integral helmet body.

[0005] Among them, the composite fiber layer is composed of a super high molecular weight polyethylene fiber and an aramid fiber mixed prepreg and a carbon fiber prepreg with a preset number of layers stacked in sequence.

[0006] The polymer layer is made of a modified polymer material. The content of each component of the modified polymer material is as follows: by mass fraction, acrylonitrile-butadiene-styrene copolymer - 45 to 55 parts, polycarbonate - 25 to 35 parts, nylon 66 - 15 to 25 parts, polyoxymethylene - 5 to 15 parts, polyborosiloxane - 6 to 10 parts, maleic anhydride - 5 to 10 parts, processing aids - 1 to 2 parts, antioxidant - 0.4 to 0.6 parts, dicumyl peroxide - 0.4 to 0.6 parts, paraffin oil - 0.1 to 0.3 parts.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: The sandwich structure composed of ultra-high molecular weight polyethylene fibers, aramid fibers, and carbon fibers in the outer composite fiber layer well matches the requirements of rigidity and toughness of the composite fiber layer, enabling both efficient protection and maintaining the integrity of the helmet under high-intensity impacts. At the same time, the composite fiber layer has excellent weather resistance, strong environmental adaptability, and small performance degradation caused by environmental stress. Moreover, the polymer layer is injection-molded onto the composite fiber layer and organically integrated into one body. The modified polymer material of the polymer layer is used to toughen, strengthen, and improve the bending, tensile, and impact strength properties. At the same time, it combines with the composite fiber layer to achieve a synergistic step effect of performance, that is, on the basis of its superior performance, the composite fiber layer can also play a role of skeleton and protection for the polymer layer, so that the polymer layer will not break when subjected to strong impacts and shear forces, while the polymer layer synergistically enhances the impact barrier and absorption capabilities of the composite fiber layer, achieving an overall improvement in the protection performance and weather resistance of the helmet.

[0008] Preferably, the ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg is composed of orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric and unsaturated polyester.

[0009] Preferably, the warp of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is aramid yarn, the weft is ultra-high molecular weight polyethylene yarn, and it is twisted in the Z direction.

[0010] Preferably, the areal density of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is 410 g / m 2 ~450 g / m 2 。

[0011] Preferably, the unsaturated polyester is a thermosetting resin, and the unsaturated polyester is transferred to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric by a hot melt transfer method.

[0012] Preferably, the mass fraction of the unsaturated resin is 28% - 32% of the mass fraction of the ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg.

[0013] Preferably, the carbon fiber prepreg is composed of left diagonal twill carbon fiber woven fabric and epoxy resin; during the weaving process of the left diagonal twill carbon fiber woven fabric, the fiber bundles are not twisted, and the epoxy resin is immersed into the carbon fiber woven fabric by a hot melt transfer method.

[0014] Preferably, the areal density of the carbon fiber prepreg is 680 g / m 2 ~720 g / m 2 。

[0015] On the other hand, the present invention also provides a preparation method of the helmet as described above, comprising the following steps:

[0016] S10: Cut the ultra-high molecular weight polyethylene fiber and aramid fiber co-woven prepreg, as well as the carbon fiber prepreg, into pieces respectively, and cut incisions on the pieces at preset angles at intervals;

[0017] S20: Lay the cut ultra-high molecular weight polyethylene fiber and aramid fiber co-woven prepreg, as well as the carbon fiber prepreg, layer by layer on the metal hot pressing male mold for helmet body forming in a preset order;

[0018] S30: Close the mold for hot pressing, and open the mold to release air at preset intervals during the pressing process, and each air release lasts for a preset duration;

[0019] S40: After the hot pressing is completed, open the mold to take out the formed composite fiber layer, cut off the flash, and polish the inner surface of the formed composite fiber layer with sandpaper;

[0020] S50: Uniformly apply epoxy resin on the outer surface of the composite fiber layer, and paste the composite fiber layer in the female mold of the injection mold, and close the mold after completion;

[0021] S60: Inject the pre-prepared modified polymer material into the injection mold through an injection molding machine to form a polymer layer, and combine it with the composite fiber layer to form an integral structure, so as to complete the helmet body with an outer composite fiber layer and an inner polymer layer structure.

[0022] Preferably, the preparation method of the modified polymer material comprises the following steps:

[0023] S01: Dry the acrylonitrile-butadiene-styrene copolymer;

[0024] S02: Weigh the acrylonitrile-butadiene-styrene copolymer, maleic anhydride, dicumyl peroxide and liquid paraffin oil according to preset mass parts, mix them evenly and extrude and pelletize them in an extruder equipped with a graft screw to obtain compound A;

[0025] S03: Weigh polycarbonate, nylon 66 and polyoxymethylene according to preset mass parts, put them into a high-speed mixer at a temperature of 80±3°C for high-speed mixing, and extrude and pelletize them in a twin-screw extruder. After completion, place the pellets in an oven at a temperature of 80±5°C for drying treatment for 2h to 4h to obtain compound B;

[0026] S04: Weigh polyborosiloxane according to the preset mass fraction, disperse it in deionized water to form a suspension, adjust the pH to 9 with NaOH solution, add the preset mass fraction of processing aids while stirring, perform ultrasonic oscillation at room temperature for 0.5 h to 1.5 h, then obtain a filter cake in a centrifuge. After washing, drying, grinding, and sieving the filter cake, compound C is obtained.

[0027] S05: Dry compound A, compound B, and compound C in a dryer at a temperature of 90 ± 5 °C for 3 h to 5 h. Weigh the preset mass fraction of antioxidant, put them into a high-speed mixer and stir evenly, then extrude and pelletize in a co-rotating twin-screw extruder to obtain the modified polymer material.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: Through the above preparation process, the hot-pressed composite fiber layer structure has high specific strength and specific modulus. Under the condition of the same or higher protection efficiency, the weight of the equipment can be effectively reduced. After being impacted by the outside world, under the combined superior performance of its high tensile strength, low elongation at break, and high impact strength, the impact force can be quickly dispersed, transferred from a small area to a large area, consume the impact kinetic energy, reduce the impact force penetrating into the helmet, and prevent the penetration of sharp instruments; and after the polymer layer is affected by the outside impact of reduced kinetic energy and increased action area, the modified polymer material can provide a large impact work absorption margin, quickly prevent and absorb the impact kinetic energy, and protect the safety of personnel. Specific Embodiments

[0029] For the convenience of understanding the description of the present invention, the present invention can be implemented in many different forms and is not limited to the examples described herein. On the contrary, the purpose of providing examples is to make the disclosure content of the present invention more thorough.

[0030] Test Example 1

[0031] This embodiment provides a helmet made of a composite material, including a helmet body. The helmet body includes a composite fiber layer and a polymer layer stacked from outside to inside in sequence; wherein, the composite fiber layer is composed of two layers of ultra-high molecular weight polyethylene fiber and aramid fiber mixed pre-impregnated materials, and one layer of carbon fiber pre-impregnated material stacked in sequence. Specifically, the stacking order is ultra-high molecular weight polyethylene fiber and aramid fiber mixed pre-impregnated material + ultra-high molecular weight polyethylene fiber and aramid fiber mixed pre-impregnated material + carbon fiber pre-impregnated material, and the thickness of the stacked composite fiber layer is 1.8 mm.

[0032] Furthermore, the ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg is composed of 70% by weight of orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric and 30% by weight of unsaturated polyester. The 30% unsaturated polyester can more completely ensure that the unsaturated polyester is impregnated into the fiber fabric, so that the material forms a higher interlayer bonding force during the hot pressing process, which is more conducive to providing the material with impact resistance and can reduce the weight of the material. In this embodiment, the surface density of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is 430g / m 2 , its warp is aramid yarn with a linear density of 1000tex, and its weft is ultra-high molecular weight polyethylene yarn with a linear density of 1000tex. Through the orthogonal weaving method, it has better fiber structure stability, so that the fiber bundle is not easy to separate and slip during external impact; and it has high specific strength and specific modulus, so that the weight of the equipment can be effectively reduced under the condition of equal or higher protection effectiveness. Preferably, the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric are twisted in the Z direction, and the double-wire parallel weaving and twisted in the Z direction are used to improve the tensile strength of the warp and weft, so that the warp and weft are tightly combined, so as to improve the fabric's ability to resist puncture and cutting, and can effectively increase the breaking force value of the fiber bundle, so as to improve the protective performance of the helmet. The unsaturated polyester is a thermosetting resin, and the adhesive is transferred to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric by the hot melt transfer method. Specifically, the steps of the hot melt transfer method are as follows:

[0033] a. Preparation of film: Spray the mixed unsaturated polyester onto the release paper with a spraying surface density of 40g / m 2 ,

[0034] b. Transfer film: The film is laminated to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric, and the film is transferred into the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric through a hot roll, pressurized at 1.5±0.1MPa, and heated at 80±3℃ to form a mixed prepreg of ultra-high molecular weight polyethylene fiber and aramid fiber. The hot melt transfer method can ensure the uniformity of the density of the unsaturated polyester per unit area and the consistency of the quality of the composite fiber layer during the processing.

[0035] It should be noted that for helmets with higher technical requirements, other embodiments can use the fiber layer structure of this embodiment as a basic unit, and higher technical requirements can be achieved by increasing the number of basic units. This embodiment adopts a sandwich structure composed of ultra-high molecular weight polyethylene fibers, aramid fibers, and carbon fibers in the outer composite fiber layer, which well matches the rigidity and toughness requirements of the composite fiber layer. It can not only achieve efficient protection but also maintain the integrity of the helmet under high-intensity impacts. At the same time, the composite fiber layer has excellent weather resistance, strong environmental adaptability, and little performance degradation caused by environmental stress.

[0036] Further, the areal density of the carbon fiber prepreg is 700 g / m 2 , and the carbon fiber prepreg with a large areal density has the characteristics of high modulus and high strength, which is beneficial to reducing the structural collapse caused by external impacts, improving the structural strength of the helmet, and ensuring the structural stability of the helmet. In this embodiment, the carbon fiber prepreg is composed of left-handed twill carbon fiber machine cloth and epoxy resin. Specifically, during the weaving process of the left-handed twill carbon fiber machine cloth, the fiber bundles are not twisted, and the epoxy resin is impregnated into the carbon fiber woven cloth by the hot melt transfer method.

[0037] Further, the polymer layer is made of a modified polymer material with a thickness of 2.2 mm. The content of each component of the modified polymer material is as follows: by mass, acrylonitrile-butadiene-styrene copolymer - 50 parts, polycarbonate - 30 parts, nylon 66 - 20 parts, polyoxymethylene - 10 parts, polyborosiloxane - 8 parts, maleic anhydride - 8 parts, processing aid - 1.5 parts, antioxidant - 0.5 parts, dicumyl peroxide - 0.5 parts, paraffin oil - 0.2 parts. In this embodiment, the polymer layer is injection-molded on the composite fiber layer to be integrally combined. The modified polymer material of the polymer layer is used to toughen, strengthen, and improve the bending, tensile, and impact strength properties. At the same time, it combines with the composite fiber layer to achieve a synergistic step effect of performance, that is, on the basis of the superior performance of the composite fiber layer, it can also play a role of skeleton and protection for the polymer layer, so that the polymer layer will not break when subjected to strong impacts and cuts, and the polymer layer synergistically improves the impact barrier and absorption ability of the composite fiber layer, achieving an overall improvement in the protection performance and weather resistance of the helmet.

[0038] The manufacturing process of the above helmet is as follows: First, prepare the modified polymer material for the polymer layer. After the composite fiber layer is hot-pressed and formed by a hot-pressed metal mold, the formed composite fiber layer is placed in an injection mold, and the polymer layer is injection-molded to form an integral structure of the helmet body with the polymer layer placed on the composite fiber layer.

[0039] First, the preparation method of the modified polymer material includes the following steps:

[0040] S01: Dry the acrylonitrile-butadiene-styrene copolymer.

[0041] S02: Weigh 50 parts by mass of acrylonitrile-butadiene-styrene copolymer, 8 parts by mass of maleic anhydride, 0.5 parts by mass of diisopropylbenzene peroxide and 0.2 parts by mass of liquid paraffin oil. After mixing evenly, extrude and pelletize in an extruder equipped with a grafting screw to obtain Compound A. Among them, the temperatures of each section of the screw barrel of the extruder are 155 °C, 180 °C, 210 °C, 210 °C, 165 °C (head) respectively. The vacuum degree of the impurity removal section is 0.12 MPa, and the screw speed is 68 r / min.

[0042] S03: Weigh 30 parts by mass of polycarbonate, 20 parts by mass of nylon 66, and 10 parts by mass of polyoxymethylene, and put them into a high-speed mixer at a temperature of 80 ± 3 °C. After the raw materials are mixed at high speed, extrude and pelletize in a twin-screw extruder. After the extrusion and pelletization are completed, place the pellets in an oven and dry them at 80 ± 5 °C for 3 h to obtain Compound B. Among them, the temperatures of each section of the screw barrel of the twin-screw extruder are 55 °C, 130 °C, 150 °C, 190 °C, 205 °C, 210 °C, 210 °C, 218 °C, 230 °C respectively. The vacuum degree of the impurity removal section is 0.12 MPa, and the screw speed is 68 r / min.

[0043] S04: Weigh 8 parts by mass of polyborosiloxane and disperse it in deionized water to form a suspension. Adjust the pH to 9 with NaOH solution, and add the specified mass parts of processing aids while stirring. Oscillate ultrasonically at room temperature for 1 h; centrifuge at 3000 r / min for 10 min. After the obtained filter cake is washed with water, dry it at 100 °C, grind it, and sieve it through a 300-mesh sieve to obtain Compound C.

[0044] S05: After drying the prepared Compound A, Compound B, and Compound C in a dryer at 90 ± 5 °C for 4 h, weigh 0.5 parts by mass of antioxidant, and put them into a high-speed mixer together, and stir for 10 min. Extrude and pelletize the uniformly mixed material in a co-rotating twin-screw extruder to obtain a modified polymer material. Among them, the temperatures of each section of the twin-screw extruder are 160 °C to 180 °C, the head temperature is 175 °C, and the screw speed is 80 r / min.

[0045] Secondly, the specific manufacturing process of the helmet includes the following steps:

[0046] S10: Cut the ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg and carbon fiber prepreg into elliptical pieces with a major axis length of 600 mm and a minor axis length of 500 mm respectively for topological fitting of the personnel head structure; and cut incisions with a length of 150 mm every 90°, so that the pieces can be spread on the helmet curved surface mold without wrinkles.

[0047] S20: Layer by layer lay the two cut ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepregs and one layer of carbon fiber prepreg on the metal hot pressing male mold for helmet body forming. Among them, during the laying process, the incision of the lower layer rotates 15° relative to the incision of the upper layer to avoid the overlap of incisions between adjacent layers.

[0048] S30: Lower the metal hot pressing female mold to close the mold for hot pressing. The hot pressing temperature is 135 ± 3 °C, the hot pressing time is 28 min, the hot pressing pressure is 18 ± 0.5 MPa, and open the mold to release air twice at the 3rd minute and the 8th minute of pressing, each time lasting 20 s.

[0049] S40: After the hot pressing is completed, open the mold to take out the formed composite fiber layer, cut off the flash, and polish the inner surface of the formed composite fiber layer with 100-mesh sandpaper. Among them, the composite fiber layer with a rough surface is more conducive to the combination with the polymer layer, and at the same time can also make the composite fiber layer firmly adhere to the injection mold.

[0050] S50: Uniformly apply epoxy resin on the outer surface of the composite fiber layer and paste it into the female mold of the injection mold, and then close the mold after completion. The epoxy resin applied to the composite fiber layer is a thermosetting material, and after thermoforming, it can quickly break away from the injection mold.

[0051] S60: Set the process conditions of the injection molding machine: zone 1 is 220 °C, zones 2 to 4 are 225 °C, zones 5 to 7 are 215 °C, the head is 233 °C, the screw speed is 180 r / min, the injection temperature is 246 °C, and the injection pressure is 125 MPa. Inject the preset prepared modified polymer material into the injection mold through the injection molding machine to form a polymer layer, and combine with the composite fiber layer to form an integral structure to complete the helmet body with an outer composite fiber layer and an inner polymer layer structure. Among them, the polymer layer is located inside, and through pressure injection molding, the polymer layer can wrap the edge of the composite fiber layer to enhance the bonding force between the two.

[0052] S70: Take out the helmet after injection molding, correct the overflow material, clean the surface, and obtain the finished helmet.

[0053] Test Example 2

[0054] The present embodiment provides a helmet made of composite materials, including a helmet body, wherein the helmet body includes a composite fiber layer and a polymer layer sequentially stacked from the outside to the inside; wherein the composite fiber layer is composed of two layers of ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg, and one layer of carbon fiber prepreg stacked in sequence. Specifically, the stacking sequence is ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg + ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg + carbon fiber prepreg, and the thickness of the stacked composite fiber layer is 1.7 mm.

[0055] Furthermore, the ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg is composed of 72% by weight of orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric and 28% by weight of unsaturated polyester. In this embodiment, the surface density of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is 410g / m 2 , the warp is an aramid yarn with a linear density of 1000tex, and the weft is an ultra-high molecular weight polyethylene yarn with a linear density of 1000tex. Preferably, the orthogonal ultra-high molecular weight polyethylene fiber and the aramid fiber woven fabric are twisted in the Z direction, and are woven with double wires and twisted in the Z direction, which improves the tensile strength of the warp and weft, making the warp and weft tightly combined, thereby achieving the purpose of improving the fabric's ability to resist puncture and cutting, and can effectively increase the breaking force value of the fiber bundle, thereby achieving the purpose of improving the protective performance of the helmet. The unsaturated polyester is a thermosetting resin, and the adhesive is transferred to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and the aramid fiber woven fabric by a hot melt transfer method. Specifically, the steps of the hot melt transfer method are as follows:

[0056] a. Preparation of film: Spray the mixed unsaturated polyester onto the release paper with a spraying surface density of 42g / m 2 ,

[0057] b. Transferring the adhesive film: Lay the adhesive film on the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric, and pass it through a hot roll, pressurize it at 1.5±0.1MPa, and heat it at 80±3℃, so that the adhesive film is transferred into the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric to form a mixed prepreg of ultra-high molecular weight polyethylene fiber and aramid fiber.

[0058] Furthermore, the surface density of the carbon fiber prepreg is 720g / m 2 In this embodiment, the carbon fiber prepreg is composed of left-hand twill carbon fiber machine cloth and epoxy resin. Specifically, during the weaving process of the left-hand twill carbon fiber machine cloth, the fiber bundles are not twisted, and the epoxy resin is impregnated into the carbon fiber machine cloth by a hot melt transfer method.

[0059] Further, the polymer layer is made of a modified polymer material and has a thickness of 2.3 mm. The contents of the components of the modified polymer material are as follows: by mass, acrylonitrile-butadiene-styrene copolymer - 55 parts, polycarbonate - 35 parts, nylon 66 - 25 parts, polyoxymethylene - 15 parts, polyborosiloxane - 10 parts, maleic anhydride - 18 parts, processing aids - 2 parts, antioxidant - 0.6 parts, dicumyl peroxide - 0.6 parts, paraffin oil - 0.3 parts. In this embodiment, the polymer layer is injection-molded onto the composite fiber layer and organically combined into one body. The modified polymer material of the polymer layer is used to toughen, strengthen, and improve the bending, tensile, and impact strength properties. At the same time, it combines with the composite fiber layer to achieve a synergistic step effect in performance, that is, on the basis of its superior performance, the composite fiber layer can also play a role of skeleton and protection for the polymer layer, so that the polymer layer will not break when subjected to strong impact and cutting, and the polymer layer synergistically improves the impact barrier and absorption ability of the composite fiber layer, achieving an overall improvement in the protection performance and weather resistance of the helmet.

[0060] Test Example 3

[0061] This embodiment provides a helmet made of a composite material, including a helmet body. The helmet body includes a composite fiber layer and a polymer layer that are sequentially stacked from outside to inside; wherein, the composite fiber layer is composed of two layers of ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg, and one layer of carbon fiber prepreg stacked in sequence. Specifically, the stacking order is ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg + ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg + carbon fiber prepreg, and the thickness of the composite fiber layer formed by stacking is 1.9 mm.

[0062] Further, the ultra-high molecular weight polyethylene fiber and aramid fiber mixed woven prepreg is composed of 68% by mass of orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric and 32% by mass of unsaturated polyester. In this embodiment, the areal density of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is 450 g / m 2 , its warp is aramid yarn with a linear density of 1000 tex, and its weft is ultra-high molecular weight polyethylene yarn with a linear density of 1000 tex. Preferably, the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is twisted in the Z direction, and is woven with double filaments and twisted in the Z direction, which improves the tensile strength of the warp and weft and makes the warp and weft tightly combined, achieving the purpose of improving the fabric's ability to resist puncture and cutting, and can effectively increase the breaking force value of the fiber bundle, achieving the purpose of improving the protection performance of the helmet. The unsaturated polyester is a thermosetting resin, and through the hot melt transfer method, the adhesive is transferred to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric. Specifically, the steps of the hot melt transfer method are as follows:

[0063] a. Preparation of the adhesive film: The mixed unsaturated polyester in proportion is sprayed onto the release paper, and the spraying surface density is 38 g / m 2 ,

[0064] b. Transfer of the adhesive film: The adhesive film is adhered to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric. Through a hot drum, pressurize at 1.5 ± 0.1 MPa and heat at 80 ± 3 °C to immerse the adhesive film into the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric, forming a mixed pre-impregnated material of ultra-high molecular weight polyethylene fiber and aramid fiber.

[0065] Further, the surface density of the carbon fiber pre-impregnated material is 680 g / m 2 . In this embodiment, the carbon fiber pre-impregnated material is composed of a left oblique twill carbon fiber woven fabric and epoxy resin. Specifically, during the weaving process of the left oblique twill carbon fiber woven fabric, the fiber bundles are not twisted, and the epoxy resin is immersed in the carbon fiber woven fabric by the hot melt transfer method.

[0066] Further, the polymer layer is made of a modified polymer material with a thickness of 2.1 mm. The content of each component of this modified polymer material is: by mass fraction, acrylonitrile-butadiene-styrene copolymer - 45 parts, polycarbonate - 25 parts, nylon 66 - 15 parts, polyoxymethylene - 5 parts, polyborosiloxane - 6 parts, maleic anhydride - 5 parts, processing aid - 1 part, antioxidant - 0.4 part, dicumyl peroxide - 0.4 part, paraffin oil - 0.1 part. In this embodiment, the polymer layer is injection-molded and integrally combined with the composite fiber layer. The modified polymer material of the polymer layer is used to toughen, strengthen, improve the bending, tensile, and impact strength properties, and at the same time combine with the composite fiber layer to achieve a synergistic step effect in performance, that is, on the basis of its superior performance, the composite fiber layer can also play a role of skeleton and protection for the polymer layer, so that the polymer layer will not break when subjected to strong impact and cutting, and the polymer layer synergistically improves the impact barrier and absorption ability of the composite fiber layer, achieving an overall improvement in the protection performance and weather resistance of the helmet.

[0067] Comparative Example 1

[0068] Conventional helmets mostly use a single polymer material, such as polycarbonate or nylon, and need to give specific ratio materials of common helmet products through the injection molding process.

[0069] 1. Perform helmet shell penetration resistance tests on Test Example 1, Test Example 2, Test Example 3, and Comparative Example 1. Among them, according to the regulations of "GA294-2012 Police Anti-riot Helmets": At normal temperature (25 ± 5 °C), use a 3 kg heavy steel cone with a height of 3.6 m to puncture the helmet shell with an energy of 106 J. If the steel cone does not penetrate the helmet shell, it is qualified. The specific test results are shown in Table 1.

[0070] Table 1: Inspection Results of the Penetration Resistance Performance of the Helmet Shell at Room Temperature

[0071] Test Example 1 Test Example 2 Test Example 3 Comparative Example 1 Whether to penetrate No No No Yes

[0072] To further verify the penetration resistance performance of the helmet shell of the embodiments of the present invention in a relatively harsh environment, the penetration resistance performance inspection of the helmet shell was carried out in a low-temperature environment and a high-temperature environment. The specific inspection results are shown in Table 2:

[0073] Table 2: Inspection Results of the Penetration Resistance Performance of the Helmet Shell at High and Low Temperatures

[0074]

[0075] It can be seen from Table 1 and Table 2 that: compared with the existing helmets, the composite fiber layer formed by two layers of ultra-high molecular weight polyethylene fiber and aramid fiber prepregs and one layer of carbon fiber prepreg in the embodiments of the present invention is formed by hot pressing die molding. This structure has high specific strength and specific modulus. After being subjected to an external impact, under the combined action of its comprehensive superior performance such as high tensile strength, low elongation at break, and high impact strength, the impact force can be quickly dispersed, transferred from a small area to a large area, consume the impact kinetic energy, reduce the impact force penetrating into the helmet, and prevent the penetration of sharp instruments. Moreover, after the embodiments of the present invention are used for 4 hours in harsh high and low temperature conditions, they still have the characteristics of reducing the impact force penetrating into the helmet and preventing the penetration of sharp instruments.

[0076] 2. The helmet shell absorption of collision energy performance inspection was carried out for Test Example 1, Test Example 2, Test Example 3 and Comparative Example 1. Among them, according to the requirements of "GA294-2012 Police Riot Helmets": at room temperature (25 ±5°C), a 5 kg heavy drop hammer is dropped from a height of 1.3 m. The helmet shell can withstand an impact of 63.7 J of energy, and the force transmitted to the test head mold during the impact should be less than 4.9 KN, and the helmet shell is qualified. The specific test results are shown in Table 3.

[0077] Table 3: Inspection Results of the Helmet Shell Absorption of Collision Energy Performance at Room Temperature

[0078]

[0079] To further verify the helmet shell absorption of collision energy performance of the embodiments of the present invention in a relatively harsh environment, the penetration resistance performance inspection of the helmet shell was carried out in a low-temperature environment and a high-temperature environment. The specific inspection results are shown in Table 4:

[0080] Table 4: Inspection Results of the Helmet Shell Absorption of Collision Energy Performance at High and Low Temperatures

[0081]

[0082] Moreover, through multiple rounds of tests, for helmets made of fiber prepregs, at low temperatures, due to the shrinkage of fiber molecular weight, the structural performance is further improved and the impact resistance is enhanced; while for helmets made of single polymer materials, low temperatures can cause an increase in the brittleness of the materials, and they are extremely prone to fragmentation after being impacted.

[0083] As can be seen from Table 1 and Table 2: Compared with existing helmets, different materials are preferably used for the polymer layer. For example, the impact strength of acrylonitrile-butadiene-styrene copolymer is significantly improved after grafting, and polyborosiloxane is a non-Newtonian fluid substance that can improve the impact resistance of the material and absorb impact energy to a certain extent; by reasonably matching their respective properties, the material can synergistically achieve high flexural strength, tensile strength, and impact strength, and this material has low low-temperature brittleness and, after toughening treatment, has the characteristics of non-fragmentation and good shrinkage on the damaged surface. When the polymer layer is subjected to an external impact with a decrease in kinetic energy and an increase in the acting area, it provides a large margin for absorbing impact energy, quickly stops and absorbs the impact kinetic energy, and protects the safety of personnel. Moreover, after being used for 4 hours under harsh high- and low-temperature conditions, the embodiments of the present invention still have strong performance in absorbing collision energy.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A helmet made of a composite material, comprising a helmet body, characterized in that, The helmet body includes a composite fiber layer and a polymer layer stacked in sequence from outside to inside; the composite fiber layer formed by hot pressing is placed in an injection mold, and the polymer layer is formed by injection molding, so that the polymer layer is placed on the composite fiber layer to form the helmet body with an integrated structure; Among them, the composite fiber layer is composed of a prefabricated number of ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepregs and carbon fiber prepregs stacked in sequence; The polymer layer is made of a modified polymer material, and the content of each component of the modified polymer material is: by mass fraction, acrylonitrile-butadiene-styrene copolymer - 45 to 55 parts, polycarbonate - 25 to 35 parts, nylon 66 - 15 to 25 parts, polyoxymethylene - 5 to 15 parts, polyborosiloxane - 6 to 10 parts, maleic anhydride - 5 to 10 parts, processing aid - 1 to 2 parts, antioxidant - 0.4 to 0.6 parts, dicumyl peroxide - 0.4 to 0.6 parts, paraffin oil - 0.1 to 0.3 parts.

2. The helmet according to claim 1, wherein, The ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg is composed of an orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric and unsaturated polyester.

3. The helmet according to claim 2, characterized in that, The warp of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is aramid yarn, the weft is ultra-high molecular weight polyethylene yarn, and it is twisted in the Z direction.

4. The helmet according to claim 3, characterized in that, The areal density of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric is 410 g / m 2 ~450 g / m 2 .

5. The helmet according to claim 2, characterized in that, The unsaturated polyester is a thermosetting resin, and the unsaturated polyester is transferred to the surface of the orthogonal ultra-high molecular weight polyethylene fiber and aramid fiber woven fabric by a hot melt transfer method.

6. The helmet according to claim 2, characterized in that, The mass fraction of the unsaturated polyester is 28% - 32% of the mass fraction of the ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg.

7. The helmet according to claim 1, characterized in that, The carbon fiber prepreg is composed of a left-handed twill carbon fiber woven fabric and epoxy resin; during the weaving process of the left-handed twill carbon fiber woven fabric, the fiber bundle is not twisted, and the epoxy resin is immersed in the carbon fiber woven fabric by a hot melt transfer method.

8. The helmet according to claim 7, characterized in that, The areal density of the carbon fiber prepreg is 680 g / m 2 ~720 g / m 2 .

9. A method for preparing a helmet according to any one of claims 1 to 8, characterized in that, Including the following steps: S10: Cut the ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg and the carbon fiber prepreg into pieces respectively, and cut incisions on the pieces at preset angles; S20: Lay the cut ultra-high molecular weight polyethylene fiber and aramid fiber mixed prepreg and the carbon fiber prepreg layer by layer on a metal hot pressing punch for helmet body forming in a preset order; S30: Close the mold for hot pressing, and open the mold to release air at preset intervals during the pressing process, and each time of air release lasts for a preset time; S40: After hot pressing, open the mold to take out the formed composite fiber layer, cut off the flash, and polish the inner surface of the formed composite fiber layer with sandpaper; S50: Uniformly apply epoxy resin on the outer surface of the composite fiber layer, paste the composite fiber layer in the female mold of the injection mold, and close the mold after completion; S60: Inject the pre-prepared modified polymer material into the injection mold through an injection molding machine to form a polymer layer, and combine it with the composite fiber layer to form an integrated structure, so as to complete the helmet body with an outer composite fiber layer and an inner polymer layer structure.

10. The preparation method of the helmet according to claim 9, wherein, The preparation method of the modified polymer material includes the following steps: S01: Dry the acrylonitrile-butadiene-styrene copolymer; S02: Weigh acrylonitrile-butadiene-styrene copolymer, maleic anhydride, diisopropylbenzene peroxide and liquid paraffin oil according to the preset mass parts. After mixing evenly, extrude and granulate in an extruder equipped with a graft screw to obtain Compound A; S03: Weigh polycarbonate, nylon 66 and polyoxymethylene according to the preset mass parts, put them into a high-speed mixer at a temperature of 80 ± 3 °C for high-speed mixing, and extrude and granulate in a twin-screw extruder. After completion, place the pellets in an oven at a temperature of 80 ± 5 °C for drying treatment for 2 h to 4 h to obtain Compound B; S04: Weigh polyborosiloxane and disperse it in deionized water to form a suspension. Adjust the pH to 9 with NaOH solution, add the preset mass parts of processing aids while stirring, ultrasonically oscillate at room temperature for 0.5 h to 1.5 h, and then obtain a filter cake in a centrifuge. After washing, drying, grinding and sieving the filter cake, obtain Compound C; S05: Dry Compound A, Compound B and Compound C in a dryer at a temperature of 90 ± 5 °C for 3 h to 5 h. Weigh the preset mass parts of antioxidant, put them into a high-speed mixer and stir evenly, and then extrude and granulate in a co-rotating twin-screw extruder to obtain the modified polymer material.

Images