High-performance ballistic helmet shell and preparation method therefor

Abstract

Disclosed in the present invention is a preparation method for a high-performance ballistic helmet shell, comprising: selecting a main body material and an appearance material of the ballistic helmet shell; on the basis of a helmet structure and a pre-tiling scheme, designing various cuts of different sizes and specifications; on the basis of the sizes of the designed cuts, cutting, arranging and processing the main body material and the appearance material to obtain cuts of different sizes and specifications; tiling the cuts of different sizes and specifications to prepare a helmet shell, so as to obtain a tiled helmet; placing the tiled helmet on a helmet male mold to perform mold closing pressing, so as to obtain a pressed helmet; performing laser cutting machining on the pressed helmet to obtain a final helmet shell. The preparation method of the present invention effectively improves the structural uniformity and the quality stability of the ballistic helmet, significantly improves the circumferential rigidity and the top rigidity of the helmet shell, improves the protection performance of the ballistic helmet, and effectively solves the problems of bubbles, bulges and the like of mold-pressed helmet bodies by means of a one-time mold-pressing process.

Description

High-performance bulletproof helmet shell and preparation method thereof Technical Field

[0001] The present invention belongs to the technical field of bulletproof protective equipment, and in particular relates to a high-performance bulletproof helmet shell and a preparation method thereof. Background Art

[0002] Bulletproof helmets absorb and dissipate the kinetic energy of projectiles or fragments, reducing their penetration and preventing penetration, effectively protecting the heads of those involved. The complex curved surface of a bulletproof helmet is the most critical factor in determining its protective performance, which is primarily influenced by its structural design, material properties, and molding process. With the rapid development of materials, helmet shell materials are gradually shifting from metal to high-performance fiber-reinforced composites. These composite helmets effectively reduce weight while significantly improving their protective performance, meeting the development requirements of lightweight and high-performance protective equipment.

[0003] At present, the fiber composite materials commonly used in bulletproof helmets are one or more of aramid fiber materials, ultra-high molecular weight polyethylene fiber materials, carbon fiber materials, etc. The density of ultra-high molecular weight polyethylene fiber is 0.97g / cm 3 , strength greater than 31.5 cN / dtex, modulus greater than 970 cN / dtex, is an ideal lightweight and high-protection bulletproof helmet material.

[0004] The helmet shell molding process primarily includes cutting and processing, shell fabrication, molding, cutting, and surface painting. Cutting and fabrication strategies influence raw material utilization, the uniformity of the shell structure, and consistent quality. The process principle is to maximize raw material utilization and ensure uniformity. To avoid wrinkles during curing, most materials are cut to specific shapes and specifications before the cut shell is fabricated. Common shapes and structures are shown in Figure 1.

[0005] The helmet shell molding process is closely related to the mold structure and the helmet laying plan, directly affecting the helmet's ultimate protective performance. Parameters such as molding temperature, time, and pressure must conform to the material's characteristics. For example, due to the low melting point, poor heat resistance, poor creep resistance, and easy deformation under stress, ultra-high molecular weight polyethylene fiber materials require strict control of molding process parameters. Summary of the Invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides a high-performance bulletproof helmet shell and a method for preparing the same. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] The present invention provides a method for preparing a high-performance bulletproof helmet shell, comprising:

[0008] Select the main material and appearance material of the bulletproof helmet shell;

[0009] Design panels of various sizes and specifications according to the helmet structure and pre-laying plan;

[0010] According to the size of the designed cutting pieces, the main body material and the appearance material are cut, laid out and processed to obtain cutting pieces of different sizes and specifications;

[0011] Using the cut pieces of different sizes to lay out the helmet shell, a finished helmet is obtained;

[0012] Placing the paved helmet on a male mold of a helmet mold and performing mold closing and pressing to obtain a pressed helmet;

[0013] The pressed helmet is subjected to laser cutting processing to obtain a final helmet shell.

[0014] In one embodiment of the present invention, the main body material and the appearance material of the bulletproof helmet shell are selected, including:

[0015] Ultra-high molecular weight polyethylene non-woven fabric with a molecular weight of 3 to 5 million is selected as the main material, and polyethylene plain prepreg fabric is selected as the appearance material.

[0016] In one embodiment of the present invention, a plurality of panels of different sizes are designed according to the helmet structure and the pre-laying scheme, including:

[0017] Eight types of cutting pieces are designed using the ultra-high molecular weight polyethylene non-woven fabric, including cutting piece No. 1, cutting piece No. 2, cutting piece No. 3, cutting piece No. 4, cutting piece No. 5, cutting piece No. 6, cutting piece No. 7 and cutting piece No. 8, wherein the eight cutting pieces have the same overall size and all include a square portion and a 3 / 4 circular portion, wherein the two outer sides of the square portion are respectively tangent to the outer circle of the 3 / 4 circular portion, and the two inner sides of the square portion are respectively aligned with the cut portion of the 3 / 4 circular portion; and the interior of each of the eight cutting pieces includes four inner cutting lines in a radial direction, adjacent inner cutting lines are perpendicular to each other, and each inner cutting line extends from the edge of the cutting piece to the center of the circle to a position close to the circle, and the four inner cutting lines do not intersect;

[0018] Cutting pieces No. 9, No. 10, and No. 11 are designed using the ultra-high molecular weight polyethylene non-woven fabric, wherein the cutting piece No. 9 is in a semicircular structure as a whole, and a notch is provided at the center of the straight edge of the semicircular structure; the cutting piece No. 10 is in a drum shape, including two parallel straight edges and outwardly protruding arc edges connected to both sides of the straight edges; and the cutting piece No. 11 is in a circular shape;

[0019] The polyethylene plain weave prepreg fabric is used to design a No. 12 cutting piece, which has a square structure. An inner cutting line is vertically extended from the middle of each side of the square structure toward the center of the square.

[0020] In one embodiment of the present invention, the inner cutting lines of the eight cutting pieces are at different positions, the two inner cutting lines of cutting piece No. 1 respectively coincide with the two inner sides of the square portion, and the other two inner cutting lines are respectively perpendicular to these two inner cutting lines, so that every two inner cutting lines are located on the same straight line, and in order of numbering, the inner cutting line of each cutting piece is rotated 10 to 20 degrees along the center of the 3 / 4 circular portion relative to the inner cutting line of the previous numbered cutting piece.

[0021] In one embodiment of the present invention, the radius of the 3 / 4 circular part of the eight types of cutting pieces is 260-350 mm, the side length of the square part is 260-350 mm, and the spacing between the inner cutting lines on the same straight line is 142-232 mm.

[0022] In one embodiment of the present invention, the radius of the semicircle of the No. 9 cutting piece is 125~175mm, the notch is triangular, the angle of the notch is 65°, and the side length is 19~25mm; in the No. 10 cutting piece, the length of each straight edge is 120~130mm, the spacing between two straight edges is 120~130mm, and the radius of each curved edge is 85mm; the radius of the No. 11 cutting piece is 60~80mm.

[0023] In one embodiment of the present invention, the side length of the No. 12 cutting piece is 480-520 mm, and each inner cutting line is 71-75 mm away from the center of the No. 12 cutting piece.

[0024] In one embodiment of the present invention, the helmet shell is paved using the cut pieces of different sizes to obtain a paved helmet, including:

[0025] Prepare 5 pieces each of No. 1, No. 2, No. 3, and No. 4, 4 pieces each of No. 5, No. 6, No. 7, and No. 8, 2 pieces of No. 12, 44 pieces of No. 9, 15 pieces of No. 10, and 33 pieces of No. 11;

[0026] Place a No. 12 piece in the helmet laying mold, overlap the four inner cutting lines in a clockwise direction, and the glue-impregnated side of the piece faces up; then, according to the combination order of No. 1 piece + No. 2 piece, No. 3 piece + No. 4 piece, No. 5 piece + No. 6 piece, No. 7 piece + No. 8 piece, and make sure that the outer shapes of the pieces completely overlap, stagger the four inner cutting lines in sequence, and overlap the inner cutting lines in a clockwise direction in the helmet laying mold. According to the principle of evenly overlapping the pieces, use No. 9 piece to reinforce the circumferential inner cutting line of the helmet, and No. 10 and No. 11 pieces to reinforce the top of the helmet. Take two pieces as a group, and take 2 for each piece. Zhang is laid out, and during the laying process, piece No. 9 is laid at the four inner cutting line positions of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 for reinforcement operation, and the number of piece No. 9 laid at piece No. 2, piece No. 4, piece No. 6, and piece No. 8 is 3, 2, 2, 2 in sequence; piece No. 11 and piece No. 10 are laid at the top position of the helmet of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 for reinforcement operation, among which the number of piece No. 11 laid at the top position of the helmet of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 is 3, 3, 3, 0 in sequence, and the number of piece No. 10 laid is 3, 3, 3, 3 in sequence;

[0027] According to the combination order of piece No. 1 + piece No. 2, piece No. 3 + piece No. 4, piece No. 5 + piece No. 6, and piece No. 7 + piece No. 8, follow the rule of two pieces as a group and take 1 piece of each piece, and repeat the laying twice. During the laying process, pieces No. 2, No. 4, No. 6, and No. 8 are reinforced with 3 pieces of No. 11 on the top of the helmet. Finally, 1 piece each of No. 1 + piece No. 2, No. 3 + piece No. 4 is laid. 3 pieces of No. 11 are laid at the top of the helmet of piece No. 2, and 1 piece of No. 12 is laid above piece No. 4, with the glue-impregnated side of the pieces facing down.

[0028] In one embodiment of the present invention, the paved helmet is placed on a male mold of a helmet mold for mold closing and pressing to obtain a pressed helmet shell, comprising:

[0029] Place the paved helmet on the male mold of the helmet mold, with the inside of the helmet facing down and the pointed corner of the helmet facing the back of the helmet shell; insert the temperature measuring line from the right end of the pointed corner of the helmet into the center, and start mold closing and pressing. The pressing temperature is 130±5℃, the constant temperature and pressure holding time is 1000±200s, the constant temperature and pressure holding pressure is 18±2MPa, and the mold opening temperature is 35±5℃. Four exhaust operations are performed during the pressing process, and the exhaust temperatures are 50℃, 70℃, 80℃, and 100℃ respectively. The female mold of the helmet mold is raised 30±10mm during exhaust.

[0030] Another aspect of the present invention provides a high-performance bulletproof helmet shell, which is prepared using the preparation method described in any one of the above embodiments.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The preparation method of the present invention has made a new design for the cutting specifications in the process of laying the helmet shell, and adopts a one-time molding process to ensure the full adhesion of the resin and the fiber material matrix in the main material and the appearance material, ensure the effective molding of the helmet shell, and reduce the negative impact of sudden heating and cooling of the material on the helmet body structure and helmet body quality during the heating and cooling segmented molding process.

[0033] 2. The cutting pieces No. 1 to No. 8 of the present invention are used as the main bulletproof material. Their external dimensions ensure that the edge of the pre-laid body of the helmet shell coincides with the edge of the helmet mold, and there is no situation where there is too much or too little material at the edge of the mold, which is beneficial to improving the utilization rate of raw materials. The design of the cutting piece's sharp corners facilitates the positioning of the pre-laid body mold and the demolding of the helmet shell during the molding process. The inner cutting lines of the cutting pieces No. 1 to No. 8 are rotated in sequence, and the positions of the inner cutting lines of the cutting pieces are evenly distributed around the helmet. During the laying of the helmet, the cutting pieces cover and overlap each other, effectively avoiding the material wrinkles formed during the pre-laid process of the helmet shell, improving the uniformity of the material around the helmet shell, and helping to reduce the impact of material unevenness on the appearance quality of the helmet shell and the stability of protective performance.

[0034] 3. This invention utilizes three panels, No. 9 through No. 11, as bulletproof reinforcements to reinforce the perimeter and top of the helmet, significantly increasing the axial and top rigidity of the helmet shell and enhancing its protective performance. Furthermore, the snap-fit ​​structure formed at the inner trimming line between panel No. 9 and panels No. 1 through No. 8 effectively enhances the structural stability of the pre-laid helmet shell, preventing the quality impact of slippage of the reinforcement panels during the pressing process.

[0035] 4. The helmet laying principle adopted by the present invention is: the order of cutting pieces is from small to large, and the inner cutting line position is overlapped and laid in the clockwise direction, which ensures the orthogonal structure of the fibers in the helmet shell and the gripping effect of the fiber buckling and interweaving in the fabric, which is beneficial to increase the number of fibers that effectively bear the impact stress wave and improve the diffusion speed of the impact stress wave. At the same time, it enhances the structural stability of the bulletproof material of the helmet main body, which is beneficial to the quality stability of the product.

[0036] 5. The present invention utilizes a one-shot compression molding process, ensuring sufficient adhesion between the resin and fiber matrix in the ultra-high molecular weight polyethylene (UHMWPE) fabric and the polyethylene plain weave prepreg fabric. This ensures efficient helmet shell formation and reduces the negative impact of sudden heating and cooling of the material during the staged heating and cooling process on the helmet's structure and quality. Furthermore, two low-temperature and two high-temperature exhaust steps during the compression process allow for the smooth expulsion of air trapped within the pre-laid helmet and volatile components from the resin during the molding process, effectively preventing bubbles and bulging in the molded helmet.

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 is a schematic diagram of a typical structure of a bulletproof helmet shell panel;

[0039] FIG2 is a flow chart of a method for preparing a high-performance bulletproof helmet shell according to an embodiment of the present invention;

[0040] FIG3 is a schematic diagram of the structure and dimensions of cutting pieces No. 1 to No. 8 provided in an embodiment of the present invention;

[0041] FIG4 is a schematic diagram of the structure and dimensions of a No. 9 to No. 11 cutting piece provided in an embodiment of the present invention;

[0042] FIG5 is a schematic diagram of the structure and dimensions of a No. 12 cutting piece provided in an embodiment of the present invention;

[0043] FIG6 is a schematic diagram of cutting and layout of various pieces provided by an embodiment of the present invention;

[0044] FIG7 is a schematic diagram of specifications and dimensions of a helmet product provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of the preparation method of a high-performance bulletproof helmet shell proposed in accordance with the present invention in conjunction with the accompanying drawings and specific embodiments.

[0046] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0047] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the article or device comprising the element.

[0048] Please refer to Figure 2, which is a flow chart of a method for preparing a high-performance bulletproof helmet shell according to an embodiment of the present invention. The preparation method includes:

[0049] S1: Select the main material and appearance material of the bulletproof helmet shell.

[0050] In this embodiment, ultra-high molecular weight polyethylene non-woven fabric (UD fabric) with high strength and high modulus and a molecular weight of 3 to 5 million is selected as the main bulletproof material. The non-woven fabric structure has no interweaving points, no fiber buckling, no reflection and transfer during shock wave propagation, faster transmission speed, and a larger number of fibers that can withstand bullet penetration. This can effectively improve the impact resistance of the helmet shell and the protective performance of the helmet.

[0051] Polyethylene plain weave pre-impregnated fabric is selected as the exterior material, which not only protects the structural integrity of the main body of the bulletproof material but also facilitates subsequent surface spraying.

[0052] S2: Design the panel structure according to the helmet structure and pre-laying plan, and design panels of various sizes and specifications.

[0053] This step designs the shape and specifications of the above-mentioned bulletproof main material and appearance material: using ultra-high molecular weight polyethylene flat cloth as the bulletproof main material, eight pieces are designed: piece 1, piece 2, piece 3, piece 4, piece 5, piece 6, piece 7 and piece 8 (pieces 1# to 8#), as shown in Figure 3. Their special shape and specifications ensure the uniformity of the helmet structure and the stability of its ballistic performance.

[0054] Specifically, the eight types of cutting pieces have the same overall size and all include a square part and a 3 / 4 circular part, wherein the two outer sides of the square part are respectively tangent to the outer circle of the 3 / 4 circular part, and the two inner sides of the square part are respectively fitted with the cut parts of the 3 / 4 circular part; and the interior of these eight types of cutting pieces includes four inner cutting lines along the radial direction, adjacent inner cutting lines are perpendicular to each other and each inner cutting line extends from the edge of the cutting piece to the center of the circle to a position close to the circle, and the four inner cutting lines do not intersect.

[0055] The eight pieces have different inner trimming lines. Specifically, the two inner trimming lines of piece 1 coincide with the inner edges of the square, while the other two inner trimming lines are perpendicular to these two lines, ensuring that each pair of inner trimming lines is aligned. In order of numbering, the inner trimming lines of each piece are rotated by a predetermined angle relative to the inner trimming line of the previous piece, along the center of the 3 / 4 circle. During this rotation, the length of some trimming lines may change.

[0056] The radius of the 3 / 4 circular portion of the eight pieces is 260-350 mm, the side length of the square portion is 260-350 mm, and the spacing between the inner cutting lines located on the same straight line is 142-232 mm.

[0057] Preferably, the radius of the 3 / 4 circular portion of the eight pieces is 260 mm, the side length of the square portion is 260 mm, and the spacing between the inner cutting lines on the same straight line is 142 mm. The length of the four inner cutting lines of piece No. 1 is 189 mm.

[0058] As shown in Figure 3, with piece 1 as the reference, the outer dimensions of pieces 2 through 8 remain unchanged. The four internal trimming lines are rotated by (10-20)°, changing their lengths. The dimensions are determined by their intersection with the outer dimension lines. For piece 5, one of the internal trimming lines intersects the sharp corner of the piece, i.e., the vertex of the square. All eight pieces face the same side upward, ensuring that the pre-laid helmet material is aligned in warp and weft.

[0059] Subsequently, ultra-high molecular weight polyethylene non-woven fabric was used as the main bulletproof material to design piece No. 9 (9# piece), piece No. 10 (10# piece) and piece No. 11 (11# piece), among which piece No. 9 had a semicircular structure as a whole, and a notch was opened in the center of the straight side of the semicircular structure; piece No. 10 was drum-shaped, including two parallel straight sides and outward-convex arc sides connected to both sides of the straight sides; piece No. 11 was circular.

[0060] In this embodiment, pieces 9, 10, and 11 are all small-sized pieces. Their different shapes determine their application locations. These three sizes of pieces are used to reinforce the perimeter and top of the helmet during the helmet laying process, effectively improving the circumferential and top stiffness of the bulletproof helmet. Piece 9 is used around the perimeter of the helmet, while pieces 10 and 11 are used on the top.

[0061] The radius of the semicircular structure of piece No. 9 is 125-175 mm, and the cut is triangular with a side length of 19-25 mm. In piece No. 10, the length of each straight edge is 120-130 mm, and the distance between the two straight edges is 120-130 mm. The radius of piece No. 11 is 60-80 mm.

[0062] Preferably, the semicircular shape of piece No. 9 has a radius of 125 mm, the notch is triangular, the notch angle is 65°, and the side length is 19 mm. In piece No. 10, each straight edge is 120 mm long, the distance between two straight edges is 120 mm, and the radius of each curved edge is 85 mm. The radius of piece No. 11 is 60 mm.

[0063] In addition, a No. 12 cutting piece (No. 12 cutting piece) was designed using polyethylene plain weave prepreg fabric. The No. 12 cutting piece is square, with inner shear lines extending vertically from the center of each side of the square toward the center. See Figure 5 , which is a schematic diagram of the structural dimensions of a No. 12 cutting piece provided in an embodiment of the present invention.

[0064] The side length of the No. 12 cutting piece is 480-520 mm, and each inner cutting line is 71-75 mm away from the center of the No. 12 cutting piece. Preferably, the side length of the No. 12 cutting piece is 480 mm, and each inner cutting line is 71 mm away from the center of the No. 12 cutting piece.

[0065] S3: According to the size of the designed cutting pieces, the main body material and the appearance material are cut, laid out and processed to obtain cutting pieces of different sizes and specifications.

[0066] Please refer to Figure 6, which is a schematic diagram of the cutting and layout of various pieces provided in an embodiment of the present invention. Specifically, the selected ultra-high molecular weight polyethylene flat fabric is cut and laid out as raw material and processed using an automatic cutting machine to obtain pieces 1 to 11, as shown in Figure 6(a). Similarly, the polyethylene plain weave prepreg fabric is cut and processed to obtain piece 12, and the cutting and layout is shown in Figure 6(b). The layout method of this embodiment can effectively improve the utilization rate of raw materials.

[0067] S4: using the cut pieces of different sizes to lay out the helmet shell to obtain a completed helmet.

[0068] The present invention provides a novel process for producing a helmet shell. Specifically, panels 1-8 are used as the main bulletproof material, panels 9-11 as the surrounding and top reinforcement materials, and panel 12 as the inner and outer surface material of the helmet. The helmet shell is then laid according to the helmet shell laying design. During the laying process, panels 1-8 are overlapped clockwise at the inner cut lines to form circumferential overlapping reinforcement. The cut edge of panel 9 is engaged with the inner cut lines of panels 1-8 to form lateral reinforcement. Panels 10-11 are laid on top of the helmet to form top reinforcement.

[0069] Specifically, please refer to Table 1. First, prepare 5 pieces each of No. 1 piece, No. 2 piece, No. 3 piece, and No. 4 piece, 4 pieces each of No. 5 piece, No. 6 piece, No. 7 piece, and No. 8 piece, 2 pieces of No. 12 piece, 44 pieces of No. 9 piece, 15 pieces of No. 10 piece, and 33 pieces of No. 11 piece.

[0070] Place two No. 12 pieces in the helmet laying mold, overlap the four inner cutting lines in a clockwise direction, and the glue-impregnated side of the pieces faces upwards; then, according to the combination order of No. 1 piece + No. 2 piece, No. 3 piece + No. 4 piece, No. 5 piece + No. 6 piece, No. 7 piece + No. 8 piece, and make sure the pieces completely overlap in shape, stagger the four inner cutting lines in turn, overlap the inner cutting lines in a clockwise direction and lay them in the helmet laying mold. According to the principle of evenly overlapping the pieces, use No. 9 piece to reinforce the inner cutting lines on the circumference of the helmet, and No. 10 and No. 11 pieces to reinforce the top of the helmet. The design principle of partial reinforcement is to take every two pieces as a group, and take 2 pieces of each piece for laying. During the laying process, piece No. 9 is laid at the 4 inner cutting lines of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 for reinforcement. The number of pieces of No. 9 laid at piece No. 2, piece No. 4, piece No. 6, and piece No. 8 is 3, 2, 2, and 2 respectively; the number of pieces of No. 11 laid at the top position of the helmet of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 is 3, 3, 3, and 0 respectively, and the number of pieces of No. 10 laid is 3, 3, 3, and 3 respectively.

[0071] According to the combination order of piece No. 1 + piece No. 2, piece No. 3 + piece No. 4, piece No. 5 + piece No. 6, and piece No. 7 + piece No. 8, follow the rule of two pieces as a group and take 1 piece of each piece, and repeat the laying twice. During the laying process, pieces No. 2, No. 4, No. 6, and No. 8 are reinforced with 3 pieces of No. 11 on the top of the helmet. Finally, 1 piece each of No. 1 + piece No. 2, No. 3 + piece No. 4 is laid. 3 pieces of No. 11 are laid at the top of the helmet of piece No. 2, and 1 piece of No. 12 is laid above piece No. 4, with the glue-impregnated side of the pieces facing down.

[0072] Table 1 Description of the structure of bulletproof helmet

[0073]

[0074] In short, the laying principle of the pieces is as follows: pieces 1 to 8 are laid in sequence to ensure that the shapes of the four pieces are completely overlapped, the four inner cutting lines are staggered in sequence, and the inner cutting line positions are overlapped and laid in the helmet laying mold in the clockwise direction. This ensures that the inner cutting lines of the pieces are staggered in sequence according to the design, the overall overlap of the pieces is uniform, and the number of layers around the helmet shell is consistent, effectively ensuring the uniformity of the helmet shell structure. Pay attention to the overlap between the pieces at each inner cutting line position to avoid the situation where the pieces are not overlapped in place, which affects the protective performance of the position. The order of the pieces is from small to large, and the inner cutting line positions are overlapped and laid in the clockwise direction to ensure the orthogonal structure of the fibers in the helmet shell, as well as the bending and interweaving of the fibers in the fabric. This is beneficial to increase the number of fibers that effectively bear the impact stress wave and increase the diffusion rate of the impact stress wave. At the same time, it enhances the structural stability of the bulletproof material of the helmet body, which is beneficial to the quality stability of the product.

[0075] The number of pieces laid in the above steps is designed according to the helmet protection level or bullet, helmet structure and mold structure. As long as the overall laying principle remains unchanged, the structural stability and material uniformity of this solution can be guaranteed.

[0076] The embodiment of the present invention has made a new design for the specifications of the cutting pieces used in the helmet shell laying process. Cut pieces No. 1 to No. 8 are used as the main bulletproof materials. Their external dimensions ensure that the edge of the pre-laid body of the helmet shell coincides with the edge of the helmet mold, and there is no situation where there is too much or too little material at the edge of the mold, which is beneficial to improving the utilization rate of raw materials. The design of the cutting piece's sharp corners facilitates the mold positioning of the pre-laid body and the demolding of the helmet shell during the molding process. The inner cutting lines of cutting pieces No. 1 to No. 8 are rotated in sequence, and the positions of the inner cutting lines of the cutting pieces are evenly distributed around the helmet. During the laying of the helmet, the cutting pieces cover and overlap each other, effectively avoiding the material wrinkles formed during the pre-laid process of the helmet shell, improving the uniformity of the material around the helmet shell, and helping to reduce the impact of material unevenness on the appearance quality of the helmet shell and the stability of the protective performance.

[0077] This invention utilizes three pieces, No. 9 through No. 11, as bulletproof reinforcement materials to reinforce the perimeter and top of the helmet, significantly increasing the axial and top stiffness of the helmet shell and enhancing its protective performance. Furthermore, the snap-fit ​​structure formed at the inner trimming line between piece No. 9 and pieces No. 1 through No. 8 effectively enhances the structural stability of the pre-laid helmet shell, preventing the quality impact of slippage of the reinforcement pieces during the pressing process.

[0078] S5: placing the paved helmet on the male mold of the helmet mold for mold closing and pressing to obtain a pressed helmet.

[0079] Specifically, place the finished helmet on the male mold of the helmet mold, with the inside of the helmet facing down and the sharp corner of the helmet facing the back of the helmet. At the same time, insert the temperature measuring wire from the right end of the sharp corner of the helmet into the center, about 10 cm inward from the edge, and start mold closing and pressing. The pressing temperature is 130℃±5℃, the constant temperature holding time is 1000±200s, the constant temperature holding pressure is 15±2MPa, and the mold opening temperature is 30±10℃. Four exhaust operations are performed during the pressing process, the exhaust temperature is 50~100℃, and the helmet mold is raised 30±10mm during exhaust.

[0080] This invention utilizes a one-shot compression molding process, ensuring sufficient adhesion between the resin and fiber matrix in the ultra-high molecular weight polyethylene (UHMWPE) free-weave fabric and the polyethylene plain weave prepreg fabric, ensuring efficient helmet shell formation and minimizing the negative impact of sudden heating and cooling of the material during the staged heating and cooling process on the helmet's structure and quality. Furthermore, two low-temperature and two high-temperature exhaust steps during the compression process allow for the smooth expulsion of air trapped within the pre-laid helmet and volatile components from the resin during the molding process, effectively preventing bubbles and bulging in the molded helmet.

[0081] S6: The pressed helmet is subjected to laser cutting processing to obtain a final helmet shell.

[0082] The pressed helmet is laser cut according to the helmet specifications shown in Figure 7, and the excess edge material is cut off according to the helmet shape size, thus obtaining a bulletproof helmet with grade IIIA protection performance in accordance with the NIJ (US bulletproof standard) 0106.01 (revised version) bulletproof helmet standard, which weighs 850~860g.

[0083] It is important to note that during the cutting process, the laser beam of the laser cutting machine cuts the flash along the edge of the helmet shell blank, ensuring a clean, burr-free cut with a straight, flat cut, and a smooth, straight edge. The arc should be smooth and free of deflection, notches, virtual edges, or missing layers. The helmet shell mentioned in the above steps refers to a specific bare helmet type that meets the ballistic performance requirements. The present embodiment does not include the polyurea spraying operation of the helmet shell.

[0084] Another embodiment of the present invention further provides a high-performance bulletproof helmet shell, which is prepared using the preparation method of the above embodiment.

[0085] Next, the helmet shells produced using the present invention were tested for ballistic performance, using the following bullet types and velocities: Level IIIA (.44 Mag) bullet type and initial velocity, as specified in NIJ 0106.01 "Ballistic Helmet Performance Test Standard" and NIJ 0101.06 "Ballistic Protection Capability of Individual Body Armor." The test conditions were: bullet size, structure, and material: (44 Magnum SJHP SC); bullet mass: 15.6 g; bullet velocity: 436 ± 15 m / s; firing range: 5 m; firing angle: 0°; and number of shots: 4 (front, rear, left, and right) / top. The test results are shown in Table 2.

[0086] Table 2. Test results of protective performance of bulletproof helmet shell

[0087]

[0088] As can be seen from Table 2, when shooting from different shooting positions including the front, left, right and back of the helmet, the high-performance bulletproof helmet prepared using the embodiment of the present invention is in an unpenetrated state. At the same time, under the premise that the bulletproof helmet is not penetrated, the bullet mark height, i.e., the depression, at each shooting position of the bulletproof helmet is less than 44 mm, indicating that the bulletproof helmet has excellent protective performance.

[0089] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance bulletproof helmet shell, characterized in that: include: Select the main material and appearance material of the bulletproof helmet shell; Design various sizes of cut pieces according to the helmet structure and pre-laying plan; According to the size of the designed cut pieces, the main body material and the appearance material are cut, laid out and processed to obtain the cut pieces of different sizes and specifications; Using the cut pieces of different sizes to lay out the helmet shell, to obtain a finished helmet; Placing the paved helmet on a male mold of a helmet mold for mold closing and pressing to obtain a pressed helmet; The pressed helmet is subjected to laser cutting processing to obtain a final helmet shell.

2. The method for preparing a high-performance bulletproof helmet shell according to claim 1, characterized in that: Select the main material and appearance material of the bulletproof helmet shell, including: Ultra-high molecular weight polyethylene non-woven fabric with a molecular weight of 3 to 5 million is selected as the main body material, and polyethylene plain weave prepreg fabric is selected as the appearance material.

3. The method for preparing a high-performance bulletproof helmet shell according to claim 1, characterized in that: According to the helmet structure and pre-laying plan, we design a variety of different sizes of cutting pieces, including: 8 kinds of cutting pieces are designed by using the ultra-high molecular weight polyethylene non-wefted fabric, including cutting piece No. 1, cutting piece No. 2, cutting piece No. 3, cutting piece No. 4, cutting piece No. 5, cutting piece No. 6, cutting piece No. 7 and cutting piece No. 8, wherein the overall size of the 8 kinds of cutting pieces is the same, and all of them include a square part and a 3 / 4 circular part, wherein the two outer sides of the square part are respectively tangent to the outer circle of the 3 / 4 circular part, and the two inner sides of the square part are respectively fitted with the cut part of the 3 / 4 circular part; and the interior of the 8 kinds of cutting pieces includes four inner cutting lines along the radial direction, the adjacent inner cutting lines are perpendicular to each other, and each inner cutting line extends from the edge of the cutting piece to the center of the circle to a position close to the circle, and the four inner cutting lines do not intersect; Cutting pieces No. 9, No. 10 and No. 11 are designed by using the ultra-high molecular weight polyethylene non-woven fabric, wherein the cutting piece No. 9 is in a semicircular structure as a whole, and a notch is provided at the center of the straight edge of the semicircular structure; the cutting piece No. 10 is in a drum shape, including two parallel straight edges and arc-shaped edges protruding outwards and connected to both sides of the straight edges; the cutting piece No. 11 is in a circular shape; The polyethylene plain weave prepreg fabric is used to design a No. 12 cutting piece, which is a square structure, and an inner cutting line is vertically extended from the middle of each side of the square structure toward the center of the square.

4. The method for preparing a high-performance bulletproof helmet shell according to claim 3, characterized in that: The positions of the inner cutting lines of the eight kinds of cutting pieces are different. The two inner cutting lines of cutting piece No. 1 coincide with the two inner sides of the square part respectively, and the other two inner cutting lines are perpendicular to these two inner cutting lines respectively, so that every two inner cutting lines are located on the same straight line. In the order of numbering, the inner cutting line of each cutting piece is rotated 10 to 20 degrees along the center of the 3 / 4 circular part relative to the inner cutting line of the previous numbered cutting piece.

5. The method for preparing a high-performance bulletproof helmet shell according to claim 3, characterized in that: The radius of the 3 / 4 circular part of the 8 types of cutting pieces is 260-350 mm, the side length of the square part is 260-350 mm, and the spacing between the inner cutting lines located on the same straight line is 142-232 mm.

6. The method for preparing a high-performance bulletproof helmet shell according to claim 3, characterized in that: The radius of the semicircle of the No. 9 cutting piece is 125~175mm, the notch is triangular, the angle of the notch is 65°, and the side length is 19~25mm; in the No. 10 cutting piece, the length of each straight edge is 120~130mm, the spacing between two straight edges is 120~130mm, and the radius of each curved edge is 85mm; the radius of the No. 11 cutting piece is 60~80mm.

7. The method for preparing a high-performance bulletproof helmet shell according to claim 3, characterized in that: The side length of the No. 12 cutting piece is 480-520 mm, and each inner cutting line is 71-75 mm away from the center of the No. 12 cutting piece.

8. The method for preparing a high-performance bulletproof helmet shell according to claim 3, characterized in that: The helmet shell is paved by using the cut pieces of different sizes to obtain a paved helmet, including: Prepare 5 pieces each of No. 1, No. 2, No. 3, and No. 4, 4 pieces each of No. 5, No. 6, No. 7, and No. 8, 2 pieces of No. 12, 44 pieces of No. 9, 15 pieces of No. 10, and 33 pieces of No. 11; Lay a No. 12 piece in the helmet laying mold, overlap the four inner cutting lines in a clockwise direction, and the glue-impregnated side of the piece faces up; then, according to the combination order of No. 1 piece + No. 2 piece, No. 3 piece + No. 4 piece, No. 5 piece + No. 6 piece, No. 7 piece + No. 8 piece, according to the complete overlap of the piece shapes, the four inner cutting lines are staggered in sequence, and the inner cutting lines are overlapped clockwise and laid in the helmet laying mold. According to the principle of uniform laying of the pieces, use No. 9 piece to reinforce the circumferential inner cutting line position of the helmet, and use No. 10 and No. 11 pieces to reinforce the top of the helmet. Take two pieces as a group, and take 2 pieces from each piece. During the laying process, piece No. 9 is laid at the four inner cutting line positions of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 for reinforcement operation, and the number of pieces No. 9 laid at piece No. 2, piece No. 4, piece No. 6, and piece No. 8 is 3, 2, 2, and 2 respectively; pieces No. 11 and No. 10 are laid at the top positions of the helmets of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 for reinforcement operation, wherein the number of pieces No. 11 laid at the top positions of the helmets of piece No. 2, piece No. 4, piece No. 6, and piece No. 8 is 3, 3, 3, and 0 respectively, and the number of pieces No. 10 laid is 3, 3, 3, and 3 respectively; According to the combination order of piece No. 1 + piece No. 2, piece No. 3 + piece No. 4, piece No. 5 + piece No. 6, and piece No. 7 + piece No. 8, follow the rule of taking 1 piece of each piece as a group with two types of pieces, and repeat the laying twice. During the laying process, pieces No. 2, No. 4, No. 6, and No. 8 are reinforced with 3 pieces of No. 11 on the top of the helmet. Finally, piece No. 1 + piece No. 2, piece No. 3 + piece No. 4 are laid, 3 pieces of No. 11 are laid at the top of the helmet of piece No. 2, and 1 piece of No. 12 is laid above piece No. 4, with the glue-impregnated side of the pieces facing down.

9. The method for preparing a high-performance bulletproof helmet shell according to claim 2, characterized in that: The paved helmet is placed on the male mold of the helmet mold for mold closing and pressing to obtain a pressed helmet shell, including: Place the finished helmet on the male mold of the helmet mold, with the inside of the helmet facing downward and the sharp corner of the helmet facing the back of the helmet shell; insert the temperature measuring line from the right end of the sharp corner of the helmet into the center, and start mold pressing. The pressing temperature is 130±5℃, the constant temperature and pressure holding time is 1000±200s, the constant temperature and pressure holding pressure is 18±2MPa, and the mold opening temperature is 35±5℃. Perform four exhaust operations during the pressing process, and the exhaust temperatures are 50℃, 70℃, 80℃, and 100℃ respectively. During exhaust, the female mold of the helmet mold is raised 30±10mm.

10. A high performance bulletproof helmet shell, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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