A non-metallic bulletproof helmet and its manufacturing device and manufacturing method

Abstract

The invention provides a non-metal bulletproof helmet and a manufacturing device and method thereof, proposes a special non-metal helmet preparation device and method and product, and realizes the improvement and optimization of the bulletproof performance of the helmet; improves the problems of uneven thickness of the helmet, large depression of the front part after being hit by bullets, optimizes the current molding process production mode, makes up for the deficiency that the helmet cannot be uniformly pressed when pressed, applies equal pressure around the helmet mold, makes the thickness of the helmet in the mold uniform, because the mold is in a closed space, and is pressurized by the surrounding oil medium liquid, according to Pascal's principle, all parts of the helmet will be subjected to high pressure of equal conditions, and the heat conduction process is also conducted by the liquid medium (compared with the traditional electric heating mode, the liquid heating method is more uniform and stable), the resin between the helmet layers melts evenly, so the finished product has good isotropy, the molded helmet shell does not have the problems of uneven force, uneven thickness distribution, etc., makes up for the defect of large depression of the front part of the helmet, and improves the overall bulletproof performance of the helmet.

Description

Technical Field

[0001] The invention belongs to the technical field of non-woven fabric production and manufacturing, in particular to a non-metal bulletproof helmet and a manufacturing device and a manufacturing method thereof. Background Art

[0002] Bulletproof helmets mainly protect against physical damage such as pistol bullets, high-speed fragments, impacts and explosions. They absorb the kinetic energy of high-speed projectiles through high-strength and high-modulus materials, prevent bullets and fragments from penetrating, and absorb energy through a buffer system to protect the safety of the head. Currently, bulletproof helmets are mainly divided into metal bulletproof helmets and non-metallic bulletproof helmets according to their material composition.

[0003] Metal bulletproof helmets are mainly produced through metal stretching or stamping. Due to their heavy weight, they will put pressure on the head and cause discomfort when used. Long-term wearing will cause cervical spondylosis. The air permeability is extremely poor (almost not breathable). And the "ricochet" phenomenon is prone to occur during the protective application process, causing secondary damage to the body and people around. Therefore, metal bulletproof helmets have been gradually eliminated.

[0004] Non-metallic bulletproof helmets are hot-pressed using multiple layers of high-performance fiber prepregs. Because of their lightness and comfort, they have become the mainstream bulletproof helmets. The helmet shell is mainly made of high-strength, high-modulus fibers, such as aramid II, aramid III, ultra-high molecular weight polyethylene, PBO, carbon fiber and polyimide. Most of them are in the form of filaments or fibers, woven by looms into woven fabrics with plain, twill, satin, square and other structures, or made of non-woven fabrics by evenly laying high-strength and high-modulus materials and bonding them with resins and films; resins (such as modified phenolic resins, modified epoxy resins, polyurethanes, polyolefins and acrylic acid, etc.) are then added to the woven fabrics or non-woven fabrics, and finally the helmet shells are made through cutting, laying, compression molding and other processes.

[0005] At present, the bulletproof performance of non-metallic bulletproof helmets can meet the requirements of Level 2 in the GA 293-2012 standard, that is, using a 54-type pistol to fire a 51-type lead-core bullet with a projectile speed of 445±10m / s. Under effective hit conditions, the helmet cannot be penetrated, and the height of the bullet marks on the side, back and top must be ≤25mm, and the height of the bullet marks on the front must be ≤30mm. The requirements for anti-fragmentation are generally in accordance with GJB 5115A-2012, using the 1.1g standard simulation. When the helmet is not penetrated, the fragment V50 value is measured, and the V50 value is required to be no less than 610m / s.

[0006] In the existing non-metallic bulletproof helmet manufacturing process, the preparation of the bulletproof helmet is to cut high-strength, high-modulus woven fabric or non-woven fabric (aramid II, aramid III, ultra-high molecular weight polyethylene, PBO, carbon fiber and polyimide, etc.) into a set shape (mostly petal shape and wind impeller shape), then rotate the cut pieces and stack them in layers, and finally use a mold to hot press (Research Progress of Fiber Reinforced Resin-based Composite Material Bulletproof Helmets. Ordnance Materials Science and Engineering, 2022, 45(04): 125-132). There is also a bulletproof helmet preparation method in which the material is cut into discs and stacked, directly cold-pressed into blanks, and then subjected to two processes of pre-forming molding and forming molding, and finally trimming, painting, hanging and other processes to obtain a finished helmet (patent: CN206556513U bulletproof helmet shell).

[0007] Regardless of the molding method of the bulletproof helmet, the helmet needs to be molded; when multiple layers of prepreg are stacked or the helmet blank with the helmet paved is molded, due to the long-term downward pressure of the ordinary hydraulic press, the initial pressure only exists in the vertical direction, and the force in other directions is generated after contacting the material, which is prone to uneven force on the material around the mold, resulting in uneven thickness distribution of the helmet, especially when the bulletproof helmet is subjected to a bullet impact test, the bullet mark height of the front is greater than the bullet mark height of the side, rear and top;

[0008] At present, in the domestic market, almost all bulletproof helmets are produced by hydraulic presses. Whether it is an upper pressure hydraulic press or a lower pressure hydraulic press, the initial pressure on the helmet during the molding process is limited to the vertical direction. Taking the lower pressure press with a male mold as an example, the helmet embryo is placed in the female mold of the press base. Since the helmet embryo is relatively loose and thick, it cannot fit tightly with the female mold. There is a certain gap between the two. When the press is pressed down to the position of the helmet embryo, the male mold will slide down with the entire helmet embryo. During the sliding process, the sides of the helmet will be worn and squeezed by the female mold, destroying the fiber structure of the side of the helmet and reducing the protective performance of the side of the helmet. In addition, since the slope of the front of the helmet is relatively gentle compared to the side and rear, the pressure received during the molding process is relatively small, which makes the thickness distribution of the helmet uneven during the molding process, resulting in a large depression after the front is hit by a bullet, and poor bulletproof performance. Therefore, the existing manufacturing process is prone to poor overall bulletproof performance of bulletproof helmets, especially poor bulletproof performance of the front. Summary of the invention

[0009] The purpose of the present invention is to provide a non-metallic bulletproof helmet and a manufacturing device and a manufacturing method thereof. Based on the existing helmet molding method and isostatic pressing concept, a special non-metallic helmet preparation device and method are proposed to achieve improvement and optimization of the helmet's bulletproof performance; the problems of uneven helmet thickness and large depression of the front part after being hit by bullets are improved, the current molding process production mode is optimized, and the deficiency that the helmet cannot be uniformly pressed during pressing is compensated. An equal pressure is applied around the helmet mold to make the thickness of the helmet in the mold uniform. Since the mold is in a closed space and is pressurized by the surrounding oil medium liquid, according to Pascal's principle, all parts of the helmet will be subjected to high pressure of equal magnitude, and the heat conduction process is also conducted by the liquid medium (compared with the traditional electric heating mode, the liquid heating method is more uniform and stable), the resin between the helmet layers melts evenly, so the finished product has good isotropy, and the molded helmet shell does not have uneven force, uneven thickness distribution and other problems, which compensates for the defect of large depression of the front part of the helmet and improves the overall bulletproof performance of the helmet.

[0010] A non-metallic bulletproof helmet and a manufacturing device and method thereof, wherein:

[0011] A non-metallic bulletproof helmet, comprising: a helmet body, a buffer pad and a suspension assembly; the buffer pad and the suspension assembly are arranged inside the helmet body;

[0012] The helmet body comprises: a helmet shell, a helmet edge sealing ring and a helmet body coating. The helmet shell is made of non-metallic material and is produced by isostatic pressing of a uniformly pressurized liquid to achieve uniform overall quality of the helmet shell and ensure high-efficiency bulletproof performance. The helmet edge sealing ring is arranged around the lower part of the helmet shell; the helmet body coating is sprayed on the outer side of the helmet shell.

[0013] As an example, the non-metallic material is a high-strength, high-modulus material with a tensile strength greater than 3 GPa and a tensile modulus greater than 80 GPa.

[0014] As an example, the high-strength, high-modulus material includes, but is not limited to, one or a combination of aramid II, aramid III, ultra-high molecular weight polyethylene, PBO, carbon fiber or polyimide.

[0015] As an example, the high-strength, high-modulus material includes, but is not limited to: a woven fabric with a plain, twill, satin or square weave structure, or a non-woven fabric made by evenly laying high-strength, high-modulus material and bonding it with a resin and a film.

[0016] A manufacturing device for a non-metallic bulletproof helmet comprises: an isostatic press and a helmet shell hydraulic unit; the isostatic press has a cylinder body built therein, and hydraulic oil can be injected into or discharged from the cylinder body through pressure increase and pressure reduction operations to complete hydraulic operations; the helmet shell hydraulic unit is arranged inside the cylinder body;

[0017] Furthermore, the helmet shell oil pressure unit comprises: an outer mold, an inner mold, an upper fixing rod, a lower fixing rod, an upper piston, a lower piston, a liquid separation ring and a vacuum pump;

[0018] The inner mold comprises: a concave mold and a convex mold;

[0019] As an example, in order to achieve a better oil pressure effect, a plurality of exhaust holes are provided above the male mold.

[0020] One end of the upper fixing rod is connected to one end of the upper piston, and the other end of the upper piston is sealed and connected to the upper part of the outer mold;

[0021] One end of the lower fixing rod is connected to one end of the lower piston, and a friction ring structure is arranged around the lower piston to ensure that when the inner pressure of the outer mold is negative, a good friction seal can be formed with the inner wall of the lower end of the outer mold, so that the upper piston and the lower piston form a closed space with the inner part of the outer mold; the outer diameter of the lower piston is slightly smaller than the inner diameter of the outer mold;

[0022] The liquid separation ring plays the role of opening and closing the valve, and is used to inject and discharge hydraulic oil and ensure the neatness of the prefabricated helmet shell;

[0023] As an example, the liquid separation ring is a double-layer sleeve structure, and multiple groups of vertically arranged through holes are evenly spaced around the outer ring and the inner ring. By rotating the outer ring or the inner ring, the valve effect of opening and closing is achieved; the diameter of the liquid separation ring is slightly larger than the diameter of the lower end piston;

[0024] As an example, the double-layer sleeve structure can ensure the uniform injection and discharge of hydraulic oil, and will not cause a large deviation of the outer mold due to excessive hydraulic injection on one side;

[0025] The lower part of the outer mold is sealedly connected to the upper part of the liquid separation ring;

[0026] The upper fixing rod and the upper piston are provided with a through exhaust passage, and the exhaust passage is communicated with the vacuum pump;

[0027] As an example, the upper piston, the lower piston, the outer mold and the liquid separation ring are all cylindrical structures.

[0028] As an example, the outer mold and the inner mold are both made of soft and retractable materials.

[0029] As an example, the structural design of the helmet shell oil pressure unit not only ensures that the prefabricated helmet shell can be subjected to equal pressure in all directions, so that the helmet shell after the product is uniform, but also ensures dry-wet separation. The hydraulic oil in the process forms a good dry-wet separation with the prefabricated helmet shell, thus avoiding liquid contamination of the product caused by the existing isostatic press oil pressure process.

[0030] A method for manufacturing a non-metallic bulletproof helmet, comprising:

[0031] Step 1: cutting operation;

[0032] The cutting operation refers to: cutting the prepreg into a shape suitable for laying a helmet;

[0033] As an example, the shapes of the available helmets include, but are not limited to: one or a combination of a fan impeller shape, a petal shape, a four-leaf clover shape or a six-leaf shape;

[0034] As an example, the prepreg refers to: a high-strength, high-modulus material that is pre-impregnated with a resin;

[0035] As an example, the resin includes, but is not limited to: one or a combination of modified phenolic, modified epoxy, polyurethane, polyolefin or acrylic;

[0036] As an example, the resin content is 10% to 30% (based on the weight percentage of the entire prepreg)

[0037] Step 2: Helmet laying operation;

[0038] The helmet laying operation refers to: laying the cut prepregs layer by layer on the pre-pressed helmet mold in a bottom-up order, relying on the resin on the surface of the prepregs to heat and bond, so as to form a helmet embryo with a multi-layer prepreg structure;

[0039] As an example, for non-metallic protective materials that are not resistant to high temperatures, such as PE (ultra-high molecular weight polyethylene), the heating and bonding operation should be omitted, and the pre-pressing process can be directly performed after laying.

[0040] Step 3: pre-pressing process;

[0041] The pre-pressing process refers to: placing the helmet blank into a downward pressing machine for a short period of time, with a pre-pressing temperature of 60-80°C, the purpose of which is to increase the interlayer adhesion between each layer of prepreg and to print the contour shape of the helmet shell on the surface of the helmet blank;

[0042] As an example, the shorter time period is: no more than 1 minute.

[0043] As an example, the purpose of using a shorter time is not to damage the fiber structure on the side of the helmet and reduce the overall protective performance of the helmet; it can also complete the contour shape of the helmet shell and prepare for the next step of the isostatic press oil pressure process.

[0044] Step 4: Trimming operation;

[0045] The trimming operation refers to: cutting the prefabricated helmet shell according to the contour shape of the helmet shell printed out in the pre-pressing process to make it into a helmet shape that matches the inner mold;

[0046] Step 5: Isostatic press oil pressure process;

[0047] The isostatic press oil pressure process uses an isostatic press to perform liquid molding on the prefabricated helmet shell, specifically:

[0048] ① Place the prefabricated helmet shell between the concave and convex molds (i.e., inner molds) of the helmet and close them, and then fix the entire inner mold on the piston at the lower end of the isostatic press;

[0049] As an example, the inner mold is made of soft rubber material;

[0050] ② Push the lower piston through the lower fixed rod to send the inner mold upward into the outer mold in the cylinder of the isostatic press. The upper piston and the lower piston form a closed connection with the upper and lower ends of the outer mold respectively. At this time, the liquid separation ring is in a locked state to ensure that the hydraulic oil inside the isostatic press will not contaminate the prefabricated helmet shell;

[0051] As an example, the outer mold is a hollow cylindrical structure;

[0052] As an example, the outer mold is also made of soft rubber material;

[0053] ③ During the upward movement of the inner mold, the vacuum pump is turned on to discharge the gas in the outer mold in real time through the exhaust channel that runs through the upper piston and the upper fixed rod. At the same time, a small amount of gas in the inner mold is also extracted along with the exhaust hole on the male mold;

[0054] ④ When the upward running inner mold contacts the upper piston, the lower fixed rod stops pushing, and the isostatic press cylinder is closed and sealed. At this time, the upper piston, the lower piston and the outer mold form a sealed space;

[0055] ⑤ Open the liquid separation ring under the lower piston to allow the hydraulic oil to spread evenly around the isostatic press cylinder to perform liquid replenishment. After the liquid replenishment is completed, set the temperature, pressure and oil pressure time;

[0056] As an example, the temperature is: 120°C ~ 165°C; the pressure is: 15MPa ~ 25MPa; the oil pressure time is: 10min ~ 30min.

[0057] ⑥ Start the isostatic press. At this time, the high-pressure and high-temperature hydraulic oil will evenly transmit the pressure and temperature to the prefabricated helmet shell through the outer mold and the inner mold, so that the prefabricated helmet shell can be subjected to equal pressure and temperature in all directions on all sides;

[0058] As an example, the hydraulic oil may be other liquid media, such as pure water;

[0059] As an example, the hydraulic oil in the cylinder of the isostatic press squeezes the outer mold, causing the outer mold to be extruded and deformed. The pressure generated by the contraction of the outer mold further causes the inner mold to be extruded and deformed. Finally, the contraction deformation pressure of the inner mold is transmitted to the prefabricated helmet shell, forming equal pressure and temperature in all directions.

[0060] Step 6: Finalization process;

[0061] The shaping process refers to: after the oil pressure time is completed, the hydraulic oil is cooled down while the pressure remains unchanged, and after the pressure is maintained at the set temperature for 1min to 10min, the vacuum pump is turned off, and the hydraulic oil in the isostatic press cylinder is discharged at the same time, and the normal pressure in the isostatic press cylinder is restored to complete the curing of the thermoplastic resin to produce a helmet shell;

[0062] As an example, the set temperature is between 40°C and 60°C;

[0063] Step 7. Close the liquid separation ring, and the lower fixed rod drives the lower piston to move downward. The inner mold is taken out by the lower piston, and the outer mold remains in the cylinder body and is not taken out, waiting to be placed in the next inner mold, and continuous operation can be performed.

[0064] As an example, the purpose of closing the liquid separation ring is to prevent residual hydraulic oil in the isostatic press cylinder from causing oil contamination to the helmet shell.

[0065] As an example, if the raw material of the prefabricated helmet shell is a non-thermoplastic resin-based prepreg, the shaping process is omitted.

[0066] As an example, both the outer mold and the inner mold are reusable.

[0067] Beneficial effects of the present invention:

[0068] 1. Compared with the traditional helmet manufacturing method, the present invention has the following advantages:

[0069] ① During the isostatic press oil pressure process, the sides of the prefabricated helmet shell are no longer squeezed by unidirectional force and wear occurs, the structure of the side fibers will not be damaged, all parts of the helmet will be subjected to equal high pressure, the structure is tight, the anti-fragment performance of the helmet is enhanced, and the fragment limit V50 value is significantly improved.

[0070] ② Through the hot pressing and shaping of the isostatic press, all parts of the helmet will be subjected to equal pressure, and the heat conduction process is also conducted by liquid medium. In the traditional helmet hot pressing process, the heat is provided by the electric heating system in the mold. The distribution of the electric heating tubes is different, so the temperature of each point on the mold surface is uneven, and when the mold temperature is set, the temperature of the heating tube itself will far exceed the set temperature. When the mold reaches the set temperature, the heating tube stops heating. At this time, the mold often exceeds the set temperature for a period of time, which will cause temperature instability. The isostatic press uses liquid medium to conduct heat, the mold is heated evenly, and the insulation is stable. Therefore, the resin between the helmet layers melts evenly, the hot pressing state of each helmet is consistent, the volatility of the helmet fragment V50 value is reduced, and the phenomenon of "high wear and low protection" will not occur, which improves the stability and consistency of the helmet's anti-fragmentation performance.

[0071] ③ All parts of the helmet will be subjected to equal pressure, and the heat conduction process is also uniformly conducted by the liquid medium. The resin between the layers of the helmet melts evenly, so the finished product has good isotropy. And because all the pressures are equal and the thickness of the helmet is uniform, even if the slope of the front of the helmet is gentle, it can still receive the same pressure as the side. The bulletproof performance of the helmet is increased, and the height of the bullet marks on the front, back, sides and top of the helmet are all reduced, especially the front. The dent after the bullet impact has been significantly reduced, which better protects the safety of the wearer.

[0072] ④ The metal molds used in traditional molding are not only heavy and complex in internal structure, but also require built-in heating and cooling devices in the concave and convex molds. The helmet molds used in the isostatic press are made of elastomeric rubber material and do not require additional heating devices. The molds are light in weight, simple in structure, and easy to make. It is easy to achieve rapid mixed production of helmets of different specifications, and the overall price is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 This is a collection of examples of shapes of helmets that can be cut during the cutting operation of a method for manufacturing a non-metallic bulletproof helmet according to the present invention.

[0074] Figure 2 The present invention is a schematic diagram of the overall structure of a manufacturing device for a non-metallic bulletproof helmet.

[0075] Figure 3 It is a three-dimensional diagram of the overall structure of a manufacturing device for a non-metallic bulletproof helmet according to the present invention.

[0076] Figure 4 The present invention is a schematic diagram of the mold decomposition in a manufacturing device for a non-metallic bulletproof helmet.

[0077] Figure 5 The present invention is a schematic diagram of a method for manufacturing a non-metallic bulletproof helmet in which a prefabricated helmet shell is placed between a concave mold and a convex mold in a closed state.

[0078] Figure 6 The present invention is a schematic diagram of the overall structure of a mold outside a manufacturing device for a non-metallic bulletproof helmet.

[0079] Figure 7 The present invention is a schematic diagram of the isostatic press oil pressure process flow of a method for manufacturing a non-metallic bulletproof helmet.

[0080] Figure 8 The invention discloses a schematic diagram of an exhaust design of a manufacturing device for a non-metallic bulletproof helmet.

[0081] Fig. 9 The present invention is a schematic diagram of the structural design of the outer ring and inner ring of a liquid separation ring of a manufacturing device for a non-metallic bulletproof helmet. DETAILED DESCRIPTION

[0082] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0083] Referring to the drawings of the specification, a non-metallic bulletproof helmet and a manufacturing device and method thereof, wherein:

[0084] A non-metallic bulletproof helmet, comprising: a helmet body, a buffer pad and a suspension assembly; the buffer pad and the suspension assembly are arranged inside the helmet body;

[0085] The helmet body comprises: a helmet shell, a helmet edge sealing ring and a helmet body coating. The helmet shell is made of non-metallic material and is produced by isostatic pressing of a uniformly pressurized liquid to achieve uniform overall quality of the helmet shell and ensure high-efficiency bulletproof performance. The helmet edge sealing ring is arranged around the lower part of the helmet shell; the helmet body coating is sprayed on the outer side of the helmet shell.

[0086] As an example, the non-metallic material is a high-strength, high-modulus material with a tensile strength greater than 3 GPa and a tensile modulus greater than 80 GPa.

[0087] As an example, the high-strength, high-modulus material includes, but is not limited to, one or a combination of aramid II, aramid III, ultra-high molecular weight polyethylene, PBO, carbon fiber or polyimide.

[0088] As an example, the high-strength, high-modulus material includes, but is not limited to: a woven fabric with a plain, twill, satin or square weave structure, or a non-woven fabric made by evenly laying high-strength, high-modulus material and bonding it with a resin and a film.

[0089] A manufacturing device for non-metallic bulletproof helmets, referring to Figure 2 As shown, it includes: an isostatic press 101 and a helmet shell oil pressure unit; the isostatic press has a cylinder 102 built in it, and hydraulic oil can be injected into or discharged from the cylinder 102 through pressure increase and pressure reduction operations to complete the oil pressure operation; the helmet shell oil pressure unit is arranged inside the cylinder 102;

[0090] Furthermore, the helmet shell oil pressure unit includes: an outer mold 103, an inner mold, an upper fixing rod 104, a lower fixing rod 105, an upper piston 106, a lower piston 107, a liquid separation ring 108 and a vacuum pump 114;

[0091] The inner mold includes: a concave mold 109 and a convex mold 110;

[0092] As an example, in order to achieve a better oil pressure effect, a plurality of exhaust holes 111 are provided above the male mold 110 .

[0093] One end of the upper fixing rod 104 is connected to one end of the upper piston 106, and the other end of the upper piston 106 is sealed and connected to the upper part of the outer mold 103;

[0094] One end of the lower fixing rod 105 is connected to one end of the lower piston 107. A friction ring structure is arranged around the lower piston 107 to ensure that when the inner pressure of the outer mold 103 is negative, it can form a good friction seal with the inner side wall of the lower end of the outer mold 103, so that the upper piston 106 and the lower piston 107 form a closed space with the inner part of the outer mold 103; the outer diameter of the lower piston 107 is slightly smaller than the inner diameter of the outer mold 103;

[0095] The liquid separation ring 108 plays the role of opening and closing the valve, and is used to inject and discharge hydraulic oil and ensure the cleanliness of the prefabricated helmet shell 112;

[0096] As an example, the liquid separation ring 108 is a double-layer sleeve structure, and multiple groups of vertically arranged through holes are evenly spaced around the outer ring 115 and the inner ring 116. By rotating the outer ring 115 or the inner ring 116, the valve effect of opening and closing is achieved; the diameter of the liquid separation ring 108 is slightly larger than the diameter of the lower end piston 107; refer to Fig. 9 As shown;

[0097] As an example, the double-layer sleeve structure can ensure that the hydraulic oil is evenly injected and discharged, and will not cause a large deviation of the outer mold 103 due to excessive hydraulic injection on one side;

[0098] The lower part of the outer mold 103 is sealedly connected to the upper part of the liquid separation ring 108;

[0099] The upper fixing rod 104 and the upper piston 106 are provided with an exhaust passage 113 which is connected to the vacuum pump 114;

[0100] As an example, the upper piston 106, the lower piston 107, the outer mold 103 and the liquid separation ring 108 are all cylindrical structures.

[0101] As an example, the outer mold 103 and the inner mold are both made of soft and retractable materials.

[0102] As an example, the structural design of the helmet shell oil pressure unit not only ensures that the prefabricated helmet shell 112 can be subjected to equal pressure in all directions, so that the helmet shell after the product is uniform, but also ensures dry-wet separation. The hydraulic oil in the process forms a good dry-wet separation with the prefabricated helmet shell 112, avoiding liquid contamination of the product caused by the existing isostatic press oil pressure process;

[0103] A method for manufacturing a non-metallic bulletproof helmet, comprising:

[0104] Step 1: cutting operation;

[0105] The cutting operation refers to: cutting the prepreg into a shape suitable for laying helmets;

[0106] As an example, the shape of the helmet that can be laid includes but is not limited to: one or a combination of a fan impeller shape, a petal shape, a four-leaf clover shape or a six-leaf shape; see Figure 1 shown.

[0107] As an example, the prepreg refers to: a high-strength, high-modulus material that is pre-impregnated with a resin;

[0108] As an example, the resin includes, but is not limited to: one or a combination of modified phenolic, modified epoxy, polyurethane, polyolefin or acrylic;

[0109] As an example, the resin content is 10% to 30% (based on the weight percentage of the entire prepreg)

[0110] Step 2: Helmet laying operation;

[0111] The helmet laying operation refers to: laying the cut prepregs layer by layer on the pre-pressed helmet mold in a bottom-up order, relying on the resin on the surface of the prepregs to heat and bond, so as to form a helmet embryo with a multi-layer prepreg structure;

[0112] As an example, for non-metallic protective materials that are not resistant to high temperatures, such as PE (ultra-high molecular weight polyethylene), the heating and bonding operation should be omitted, and the pre-pressing process can be directly performed after laying.

[0113] Step 3: pre-pressing process;

[0114] The pre-pressing process refers to: placing the helmet blank into a downward pressing machine for a short period of time, with a pre-pressing temperature of 60-80°C, the purpose of which is to increase the interlayer adhesion between each layer of prepreg and to print the contour shape of the helmet shell on the surface of the helmet blank;

[0115] As an example, the shorter time period is: no more than 1 minute.

[0116] As an example, the purpose of using a shorter time is not to damage the fiber structure on the side of the helmet and reduce the overall protective performance of the helmet; it can also complete the contour shape of the helmet shell and prepare for the next step of the isostatic press oil pressure process.

[0117] Step 4: Trimming operation;

[0118] The trimming operation refers to: cutting the prefabricated helmet shell 112 according to the contour shape of the helmet shell printed out in the pre-pressing process, so as to make it into a helmet shape that matches the inner mold;

[0119] Step 5: Isostatic Press Oil Pressure Process; refer to Figure 7 As shown;

[0120] The isostatic press oil pressure process uses an isostatic press to perform liquid molding on the prefabricated helmet shell, specifically:

[0121] ① Place the prefabricated helmet shell between the helmet concave mold 109 and the convex mold 110 and close them, see Figure 5 As shown, the entire inner mold is then fixed on the piston 107 at the lower end of the isostatic press;

[0122] As an example, the inner mold is made of soft rubber material;

[0123] ② The lower piston 107 is pushed by the lower fixed rod 105 to send the inner mold upward into the outer mold 103 in the cylinder 102. The upper piston 106 and the lower piston 107 form a sealed connection with the upper and lower ends of the outer mold 103 respectively. At this time, the liquid separation ring 108 is in a locked state to ensure that the hydraulic oil inside the isostatic press will not contaminate the prefabricated helmet shell 112;

[0124] As an example, the outer mold 103 is a hollow cylindrical structure;

[0125] As an example, the outer mold 103 is also made of soft rubber material;

[0126] ③ During the upward movement of the inner mold, the vacuum pump 114 is turned on to exhaust the gas in the outer mold 103 in real time through the exhaust channel 113 that passes through the upper piston 106 and the upper fixed rod 104. At the same time, a small amount of gas in the inner mold is also extracted along with the exhaust hole 111 on the male mold 110; see Figure 8 As shown;

[0127] ④ When the inner mold 109 moving upward contacts the upper piston 106, the lower fixed rod 105 stops pushing, and the isostatic press cylinder 102 closes the seal. At this time, the upper piston 106, the lower piston 107 and the outer mold 103 form a sealed space;

[0128] ⑤ Open the liquid separation ring 108 below the lower piston 107 to allow the hydraulic oil to diffuse evenly around the isostatic press cylinder 102 for liquid replenishment. After the liquid replenishment is completed, set the temperature, pressure and oil pressure time;

[0129] As an example, the temperature is: 120°C ~ 165°C; the pressure is: 15MPa ~ 25MPa; the oil pressure time is: 10min ~ 30min.

[0130] ⑥ Start the isostatic press. At this time, the high-pressure and high-temperature hydraulic oil evenly transmits the pressure and temperature to the prefabricated helmet shell 112 through the outer mold 103 and the inner mold, so that the prefabricated helmet shell 112 can be subjected to equal pressure and temperature in all directions on all sides;

[0131] As an example, the hydraulic oil may be other liquid media, such as pure water;

[0132] As an example, the hydraulic oil in the cylinder of the isostatic press squeezes the outer mold 103, causing the outer mold 103 to be extruded and deformed. The pressure generated by the contraction of the outer mold 103 further causes the inner mold to be extruded and deformed. Finally, the contraction deformation pressure of the inner mold is transmitted to the prefabricated helmet shell 112, forming equal pressure and temperature in all directions.

[0133] Step 6: Finalization process;

[0134] The shaping process refers to: after the oil pressure time is completed, the hydraulic oil is cooled down while the pressure remains unchanged, and after the pressure is maintained at the set temperature for 1min to 10min, the vacuum pump 114 is turned off, and the hydraulic oil in the isostatic press cylinder 102 is discharged at the same time, and the normal pressure in the isostatic press cylinder 102 is restored to complete the curing of the thermoplastic resin to produce a helmet shell;

[0135] As an example, the set temperature is between 40°C and 60°C;

[0136] Step 7, close the liquid separation ring 108, and the lower fixed rod 105 drives the lower piston 107 to move downward, and the inner mold is taken out by the lower piston 107, and the outer mold 103 remains in the cylinder body 102 and is not taken out, waiting to be placed in the next inner mold, and continuous operation can be performed.

[0137] As an example, the purpose of closing the liquid separation ring 108 is to prevent the residual hydraulic oil in the isostatic press cylinder 102 from causing oil pollution to the helmet shell.

[0138] As an example, if the raw material of the prefabricated helmet shell 112 is a non-thermoplastic resin-based prepreg, the shaping process is omitted.

[0139] As an example, both the outer mold 103 and the inner mold are reusable.

[0140] In order to better understand the principle design of the manufacturing method of a non-metallic bulletproof helmet of the present invention, an example is now given to illustrate;

[0141] Example 1:

[0142] Aramid II woven fabric prepreg is used as the raw material for non-metallic bulletproof helmets. The aramid II yarn specification used is 1100dtex, the resin is modified phenolic resin, and the prepreg surface density is 405g / m 2 , the resin content is 15% (based on the weight percentage of the entire prepreg);

[0143] The aramid II woven fabric prepreg is cut into six sheets and laid on a pre-pressed helmet mold. Each layer of prepreg is staggered by 5°, and a total of 23 layers are laid. During the laying process, a hot air gun is used to heat the resin between the prepreg layers to soften and bond them to form a helmet embryo. After the laying is completed, the helmet embryo is removed from the pre-pressed helmet mold.

[0144] The helmet embryo is placed in a downward pressing machine for molding, with the temperature set to 80°C, the pressure to 20MPa, and the time set to 50 seconds. After the pre-pressing is completed, the helmet embryo is taken out;

[0145] As an example, at this time, we can observe whether the indentation produced by the mold is within the range of the inner surface of the helmet embryo. If it is beyond the range, re-prepress;

[0146] According to the helmet shell imprint produced in the pre-pressing process, the helmet embryo is cut by a saw blade cutting machine so that the embryo forms a prefabricated helmet shell 112 that matches the mold model;

[0147] The prefabricated helmet shell 112 is placed in the concave mold 109 and the convex mold 110 made of rubber, and the molds are closed. Then the entire inner mold is fixed on the lower piston 107 and sent into the cylinder 102 for sealing. After sealing, the vacuum pump 114 is turned on to extract the residual air in the outer mold 103 and the inner mold through the vacuum pump 114. Then, the liquid separation ring 108 is opened by rotation control to perform the liquid replenishment operation. The medium is glycerol, the set temperature is 155°C, the pressure is 25MPa, and the pressure holding time is 20min.

[0148] After the oil pressure is over, the hydraulic oil is cooled to 50°C while the pressure remains unchanged. After reaching the set temperature, the pressure is maintained for minutes. The vacuum pump is turned off and the hydraulic oil in the isostatic press cylinder 102 is discharged at the same time. The normal pressure in the isostatic press cylinder 102 is restored to complete the curing of the thermoplastic resin and produce a helmet shell.

[0149] Close the liquid separation plate 108 and open the sealing plate at the bottom of the cylinder 102. The inner mold is brought out by the lower piston. During the bringing out process, the lower piston 107 presses the liquid back and closes the liquid separation ring 108 at the same time. The outer mold 103 remains in the cylinder 102 and is not taken out.

[0150] The prepared helmet was tested according to the Level 2 method in GA 293-2012 "Police Bulletproof Helmets and Masks", using a Type 54 pistol to fire a Type 51 lead core bullet to test the bullet hole height. The performance of the helmet prepared by the special method in the present invention is compared with the conventional process. The maximum bullet hole height of the front part of the helmet is reduced by about 15mm, and the maximum bullet hole height of other parts is reduced by about 8mm.

[0151] According to the anti-fragmentation requirements in GJB 5115A-2012 "Technical Performance Requirements for Safety of Military Bulletproof Helmets", 17 grains (1.1 grams) standard simulated fragments were used to test the anti-fragmentation limit V50 value of the helmet. The performance of the helmet prepared by the special method in the present invention is compared with the helmet produced by the conventional process, and the measured V50 value is increased by an average of 25m / s; the maximum and minimum V50 difference of the 10 helmets is reduced from the original 44m / s to 21m / s, and the product stability is improved.

[0152] Example 2:

[0153] PE (ultra-high molecular weight polyethylene) non-woven fabric prepreg is used as the raw material for non-metallic bulletproof helmets. The PE yarn specification used is 1100dtex, the resin is water-based polyurethane, and the prepreg surface density is 110g / m 2 , resin content is 18%;

[0154] The PE non-woven fabric prepreg was cut into a four-leaf clover shape, with a total of 57 layers, and stacked according to the direction of the filaments in the non-woven fabric. Then, it was placed in an oven, set to a temperature of 90°C (not high temperature), heated for 10 minutes to soften the prepreg, and the laminated prepreg was taken out after heating;

[0155] Pull and fix the four corners of the laminated prepreg, lay it horizontally on the downward pressure press mold, start pre-pressing, set the temperature to 80℃, the pressure to 10MPa, and the time to 1min. After the pre-pressing is completed, take out the helmet embryo;

[0156] According to the contour produced by the pre-pressing, the helmet embryo is cut using a saw blade cutting machine, so that the helmet embryo is formed into a prefabricated helmet shell 112 that matches the mold model;

[0157] The prefabricated helmet shell is placed in the rubber concave mold 109 and the convex mold 110 and closed. Then the inner mold is fixed on the lower piston 107 and sent into the cylinder 102 for sealing. After sealing, the vacuum pump 114 is turned on to extract the residual air in the outer mold 103 and the inner mold. Then, the liquid separation ring 108 is opened by rotation to perform the liquid replenishment operation. The medium is glycerol, the set temperature is 125°C, the pressure is 25MPa, and the oil pressure time is 20min.

[0158] After the oil pressure time is over, the vacuum pump 114 is turned off, and the hydraulic oil in the isostatic press cylinder 102 is discharged at the same time, and the normal pressure in the isostatic press cylinder is restored to complete the curing of the thermoplastic resin to produce a helmet shell;

[0159] Close the liquid separation ring 108, and the lower fixed rod 105 drives the lower piston 107 to move downward, and the inner mold is taken out by the lower piston, and the outer mold remains in the cylinder body and is not taken out, waiting for the next inner mold to be placed, and continuous operation can be performed.

[0160] The prepared helmet was tested according to the Level 2 method in GA 293-2012 "Police Bulletproof Helmets and Masks", and a 51-type lead core bullet was fired from a 54-type pistol to test the bullet hole height. The performance of the helmet prepared by the special method in the present invention was compared with that of the conventional process, and the maximum bullet hole height of the front part of the helmet was reduced by about 22 mm, and the maximum bullet hole height of other parts was reduced by about 13 mm; according to the anti-fragmentation requirements in GJB5115A-2012 "Safety Technical Performance Requirements for Military Bulletproof Helmets", a 17-grain (1.1-gram) standard was used to simulate fragments to test the anti-fragmentation limit V50 value of the helmet. The performance of the helmet prepared by the special method in the present invention was compared with that of the helmet produced by the conventional process, and the measured V50 value was increased by an average of 21 m / s; the maximum and minimum V50 difference of 10 helmets decreased from the original 39 m / s to 23 m / s, and the product stability was improved.

[0161] During the isostatic press oil pressure process, the sides of the prefabricated helmet shell are no longer squeezed by unidirectional force to cause wear, the structure of the side fibers will not be damaged, all parts of the helmet will be subjected to high pressures of equal magnitude, the structure is compact, the anti-fragmentation performance of the helmet is enhanced, and the fragmentation limit V50 value is significantly improved.

[0162] Through the hot pressing and shaping of the isostatic press, all parts of the helmet will be subjected to equal pressure, and the heat conduction process is also conducted by liquid medium. In the traditional helmet hot pressing process, heat is provided by the electric heating system in the mold. The distribution of electric heating tubes is different, so the temperature of each point on the mold surface is uneven, and when the mold temperature is set, the temperature of the heating tube itself will far exceed the set temperature. When the mold reaches the set temperature, the heating tube stops heating. At this time, the mold often exceeds the set temperature for a period of time, which will cause temperature instability. The isostatic press uses liquid medium to conduct heat, the mold is heated evenly, and the insulation is stable. Therefore, the resin between the helmet layers melts evenly, the hot pressing state of each helmet is consistent, the volatility of the helmet fragment V50 value is reduced, and the phenomenon of "high wear and low protection" will not occur, which improves the stability and consistency of the helmet's anti-fragmentation performance.

[0163] All parts of the helmet will be subjected to equal pressure, and the heat conduction process is also uniformly conducted by the liquid medium. The resin between the helmet layers melts evenly, so the finished product has good isotropy. And because all the pressures are equal and the thickness of the helmet is uniform, even if the slope of the front of the helmet is gentle, it can still receive the same pressure as the side. The bulletproof performance of the helmet is increased, and the height of the bullet marks on the front, back, sides and top of the helmet are all reduced, especially the front. The dent after the bullet impact has been significantly reduced, which better protects the safety of the wearer.

[0164] The metal molds used in traditional molding are not only heavy and have complex internal structures, but also require built-in heating and cooling devices in the concave and convex molds. The helmet molds used in the isostatic press are made of elastomeric rubber material and do not require additional heating devices. The molds are light in weight, simple in structure, and easy to make. It is easy to achieve rapid mixed production of helmets of different specifications, and the overall price is low.

[0165] The above are only preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and core ideas of the present invention, and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A manufacturing device for a non-metallic bulletproof helmet, characterized in that: include: Isostatic press and helmet shell hydraulic unit; the isostatic press has a built-in cylinder, and hydraulic oil can be injected into or discharged from the cylinder through pressure increase and pressure reduction operations to complete the hydraulic operation; The helmet shell oil pressure unit is arranged inside the cylinder body; The helmet shell oil pressure unit comprises: an outer mold, an inner mold, an upper fixing rod, a lower fixing rod, an upper piston, a lower piston, a liquid separation ring and a vacuum pump; The inner mold comprises: a concave mold and a convex mold; a plurality of exhaust holes are arranged above the convex mold; One end of the upper fixing rod is connected to one end of the upper piston, and the other end of the upper piston is sealed and connected to the upper part of the outer mold; One end of the lower fixing rod is connected to one end of the lower piston, and a friction ring structure is arranged around the lower piston to ensure that when the inner pressure of the outer mold is negative, a good friction seal can be formed with the inner wall of the lower end of the outer mold, so that the upper piston and the lower piston form a closed space with the inner part of the outer mold; the outer diameter of the lower piston is slightly smaller than the inner diameter of the outer mold; The liquid separation ring plays the role of opening and closing the valve, and is used to inject and discharge hydraulic oil and ensure the neatness of the prefabricated helmet shell; The lower part of the outer mold is sealedly connected to the upper part of the liquid separation ring; The upper fixing rod and the upper piston are provided with a through exhaust passage, and the exhaust passage is communicated with the vacuum pump; The diameter of the liquid separation ring is slightly larger than the diameter of the lower end piston.

2. A manufacturing device for a non-metallic bulletproof helmet according to claim 1, characterized in that: The liquid separation ring is a double-layer sleeve structure, and multiple groups of vertically arranged through holes are evenly spaced around the outer ring and the inner ring. The valve effect of opening and closing can be achieved by rotating the outer ring or the inner ring. The double-layer sleeve structure can ensure the uniform injection and discharge of hydraulic oil, and will not cause a large deviation of the outer mold due to excessive hydraulic injection on one side.

3. The manufacturing device of a non-metallic bulletproof helmet according to claim 2 is characterized in that: The upper piston, the lower piston, the outer mold and the liquid separation ring are all cylindrical structures.

4. The manufacturing device of a non-metallic bulletproof helmet according to claim 3 is characterized in that: The outer mold and the inner mold are both made of soft and retractable materials.

5. A method for manufacturing a non-metallic bulletproof helmet according to claim 1, characterized in that: include: Step 1: cutting operation; The cutting operation refers to cutting the prepreg into a shape suitable for laying a helmet; the prepreg refers to a high-strength, high-modulus material pre-impregnated with resin; Step 2: Helmet laying operation; The helmet laying operation refers to: laying the cut prepregs layer by layer on the pre-pressed helmet mold in a bottom-up order, relying on the resin on the surface of the prepregs to heat and bond, so as to form a helmet embryo with a multi-layer prepreg structure; Step 3: pre-pressing process; The pre-pressing process refers to: placing the helmet blank into a downward pressing machine for a short period of time, with a pre-pressing temperature of 60-80°C, the purpose of which is to increase the interlayer adhesion between each layer of prepreg and to print the contour shape of the helmet shell on the surface of the helmet blank; Step 4: Trimming operation; The trimming operation refers to: cutting the prefabricated helmet shell according to the contour shape of the helmet shell printed out in the pre-pressing process to make it into a helmet shape that matches the inner mold; Step 5: Isostatic press oil pressure process; The isostatic press oil pressure process uses an isostatic press to perform liquid molding on the prefabricated helmet shell, specifically: ① Place the prefabricated helmet shell between the concave and convex molds (i.e., inner molds) of the helmet and close them, and then fix the entire inner mold on the piston at the lower end of the isostatic press; ② Push the lower piston through the lower fixed rod to send the inner mold upward into the outer mold in the cylinder of the isostatic press. The upper piston and the lower piston form a closed connection with the upper and lower ends of the outer mold respectively. At this time, the liquid separation ring is in a locked state to ensure that the hydraulic oil inside the isostatic press will not contaminate the prefabricated helmet shell; ③ During the upward movement of the inner mold, the vacuum pump is turned on to discharge the gas in the outer mold in real time through the exhaust channel that runs through the upper piston and the upper fixed rod. At the same time, a small amount of gas in the inner mold is also extracted along with the exhaust hole on the male mold; ④ When the upward running inner mold contacts the upper piston, the lower fixed rod stops pushing, and the isostatic press cylinder is closed and sealed. At this time, the upper piston, the lower piston and the outer mold form a sealed space; ⑤ Open the liquid separation ring under the lower piston to allow the hydraulic oil to spread evenly around the isostatic press cylinder to perform liquid replenishment. After the liquid replenishment is completed, set the temperature, pressure and oil pressure time; ⑥ Start the isostatic press. At this time, the high-pressure and high-temperature hydraulic oil will evenly transmit the pressure and temperature to the prefabricated helmet shell through the outer mold and the inner mold, so that the prefabricated helmet shell can be subjected to equal pressure and temperature in all directions on all sides; Step 6: Finalization process; The shaping process refers to: after the oil pressure time is completed, the hydraulic oil is cooled down while the pressure remains unchanged, and after the pressure is maintained at the set temperature for 1min to 10min, the vacuum pump is turned off, and the hydraulic oil in the isostatic press cylinder is discharged at the same time, and the normal pressure in the isostatic press cylinder is restored to complete the curing of the thermoplastic resin to produce a helmet shell; Step 7. Close the liquid separation ring, and the lower fixed rod drives the lower piston to move downward. The inner mold is taken out by the lower piston, and the outer mold remains in the cylinder body and is not taken out, waiting to be placed in the next inner mold, and continuous operation can be performed.

6. The manufacturing method according to claim 5, characterized in that: The shapes that can be used for laying helmets include: one or a combination of fan impeller shape, petal shape, four-leaf clover shape or six-leaf shape.

7. The manufacturing method according to claim 5, characterized in that: The outer mold and the inner mold are both reusable.

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