Bulletproof aramid polyurea composite material based on ultraviolet modification and preparation method thereof

Abstract

The application provides an ultraviolet-modified bulletproof aramid fiber polyurea composite material and a preparation method thereof, and relates to the technical field of fiber fabric modification. The application comprises the following steps: fiber pretreatment, removing impurities on the surface of aramid fiber; ultraviolet modification of aramid fiber, increasing the surface roughness; preparation of a polyurea coating layer to obtain a polyurea coating material; and spraying the prepared polyurea coating material onto the modified aramid fiber material to obtain an aramid fiber polyurea composite fabric. Compared with the prior art, the application promotes the grafting of glycidyl methacrylate on the surface of aramid fiber through ultraviolet irradiation, makes the surface of aramid fiber rougher, introduces an epoxy group on the surface of aramid fiber, improves the adhesion with polyurea, can better combine with the polyurea coating layer, increases the impact resistance of the aramid fiber polyurea composite material, improves the bulletproof performance of the composite fabric, and the softness and air permeability of the aramid fiber polyurea composite fabric are also improved, and the comfort is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fiber fabric modification, in particular to an ultraviolet modified anti-ballistic aramid polyurea composite material and a preparation method thereof. BACKGROUND

[0002] Aramid fibers have high strength, high modulus, heat resistance, corrosion resistance and other advantages, and have excellent strength and deformation characteristics, and have good application prospects in safety protection engineering fields such as explosion prevention, shock resistance and impact resistance. Because the surface of aramid fiber has high crystallinity and lacks polar functional groups in the macromolecular chain, the surface has chemical inertness and smoothness, which leads to poor adhesion between the aramid fiber and the matrix material, so the aramid fiber needs to be treated to improve the adhesion between the aramid fiber and the matrix material.

[0003] Aramid fiber modification is to improve the surface chemical activity of the fiber and increase the surface roughness to achieve good chemical bonding and mechanical interlocking between the aramid fiber and the matrix material. Ultraviolet irradiation is a physical modification method, which increases the number of active groups on the surface of aramid fiber through irradiation of the rays, increases the surface roughness to increase the surface energy, and because of its fast reaction speed, low operation cost and simple equipment, it is one of the effective ways to increase the bullet resistance of aramid fiber. The traditional aramid material has the problems of poor flame retardant performance and difficult to meet the actual demand of bullet resistance, and the traditional polyurea material has the problems of large hardness, poor softness, poor air permeability and other problems, resulting in poor comfort.

[0004] A meta-aramid fabric with surface functional modification is disclosed in Chinese patent No. 201910295485.4. The meta-aramid fabric is treated with a modification liquid composed of N,N-dimethylacetamide, LiCl and inorganic functional nanoparticles, so that the fiber surface macromolecules react with N,N-dimethylacetamide and LiCl to form a micro-dissolved layer, and the inorganic functional nanoparticles on the fiber surface are extruded into the micro-dissolved layer under the action of positive pressure, and then under the condition of high temperature and negative pressure, N,N-dimethylacetamide in the micro-dissolved layer volatilizes and separates, and the inorganic functional nanoparticles solidify on the surface of the meta-aramid fiber, enhancing the flame retardant, antistatic and radiation resistance functions of the meta-aramid surface layer.

[0005] The Chinese patent application No. 202310241904.2 discloses a method for modifying bulletproof fiber fabric in harsh environment based on copper-silver oxide, which increases the impact resistance of the fiber fabric and effectively improves the protection effect of the fiber fabric on the bullet. After pretreatment such as pickling and alkali washing to remove surface impurities, the fiber fabric is immersed in a vinyl acetic acid ethanol solution to improve its surface performance, then immersed in a copper hydroxide solution to generate copper hydroxide, and then immersed in a silver hydroxide solution to generate silver hydroxide on the surface, and finally a composite oxide layer of copper oxide and silver oxide is formed, which can significantly enhance the resistance to harsh environments such as heat and strong ultraviolet light, and the bulletproof performance of the fiber fabric can be maintained for a long time.

[0006] The Chinese patent application No. 202111365292.5 discloses a polyurea-metal-polyurea composite structure for improving bulletproof and explosion-proof performance and a preparation method. A 3mm bulletproof polyurea layer is sprayed on one side of the metal plate, and a 5mm-15mm explosion-proof polyurea layer is sprayed on the other side. The hardening, strengthening and interface failure of the polyurea elastomer under strong impact enhance the bulletproof and explosion-proof performance of the polyurea-metal composite structure, achieving the maximum comprehensive bulletproof and explosion-proof performance with the original protective material / structure and making a significant contribution to the lightweight protection field. SUMMARY

[0007] In view of the defects of the prior art, the present application provides a bulletproof aramid polyurea composite material based on ultraviolet modification and a preparation method thereof. The method makes the aramid fiber and the polyurea coating have good connection, increases the impact resistance of the composite material, and improves the bulletproof performance of the composite fabric.

[0008] The specific technical solution is a preparation method of a bulletproof aramid polyurea composite material based on ultraviolet modification, which includes the following steps:

[0009] S1, fiber pretreatment, removing surface impurities of aramid,

[0010] S2, ultraviolet modification of aramid, increasing surface roughness,

[0011] S3, preparation of polyurea coating, including the following steps:

[0012] S31, stirring aldehyde compound and mercapto compound in water solvent until the viscosity no longer increases to obtain aldehyde-terminated polyhemithioformaldehyde precursor,

[0013] S32, stirring isocyanate compound and amino compound in water solvent until the viscosity no longer increases to obtain amino-terminated polyurea precursor,

[0014] S33, mixing the solutions obtained in steps S31 and S32, stirring for 2-3 hours, and curing in a drying oven at 80-88°C for 24-36 hours to obtain a polyurea coating material,

[0015] S4, spraying the polyurea coating material prepared in step S3 onto the modified aramid fiber material obtained in step S2, with a spraying thickness of 1.5-2 mm, to obtain an aramid polyurea composite fabric.

[0016] Preferably, step S2 comprises the steps of:

[0017] S21, preparing a photoinitiator using acetone as a solvent and benzophenone as a solute,

[0018] S22, adding glycidyl methacrylate with a mass fraction of 2.5%-20% to the photoinitiator solution,

[0019] S23, immersing aramid fibers in the mixed solution obtained in step S22, purging the solution with pure nitrogen for 5-10 min to eliminate oxygen, and irradiating with 300-400 mm ultraviolet light under a 500 V high-pressure mercury lamp at room temperature for 10-30 min,

[0020] S24, removing the aramid fibers obtained in step S23, washing with ethanol and distilled water for more than three times to remove physically absorbed monomers or homopolymers, and drying in a vacuum oven for 10-13 h at an oven temperature of 90-100°C.

[0021] Preferably, the mass fraction of the photoinitiator prepared in step S21 is 2.5%.

[0022] Preferably, the ultraviolet irradiation time in step S23 is 15 min.

[0023] Preferably, the drying time in step S24 is 12 h.

[0024] Preferably, in step S31, the mass ratio of the aldehyde compound to the mercapto compound is 1:1.2-1.5; and in step S32, the mass ratio of the isocyanate compound to the amino compound is 1:3.2-3.7.

[0025] Preferably, in step S31, the aldehyde compound is triformylphloroglucinol and the mercapto compound is bis(3-mercaptopropionate)glycol, with a mass ratio of 1:1.4; and in step S33, the isocyanate compound is phenylene dimethylene diisocyanate and the amino compound is amino-terminated polytetrahydrofuran, with a mass ratio of 1:3.6.

[0026] Preferably, step S1 comprises the steps of:

[0027] S11, place aramid fibers in anhydrous ethanol solution and ultrasonic cleaning for 20-30 min, the ultrasonic temperature is 20-30 DEG C, the removal of surface oil stains and impurities is realized by ultrasonic immersion,

[0028] S12, the cleaned aramid fibers are placed in a vacuum oven and dried for 4-6 h, and the vacuum drying temperature is 90-100 DEG C.

[0029] Preferably, the concentration of the anhydrous ethanol solution used in step S11 is 99.5%.

[0030] The bulletproof aramid polyurea composite material based on ultraviolet modification is prepared by the above preparation method.

[0031] Compared with the prior art, the application promotes the surface grafting of glycidyl methacrylate on aramid fibers by ultraviolet irradiation, makes the surface of aramid fibers more rough, introduces epoxy groups on the surface of aramid fibers, improves the adhesion with polyurea, can better combine with the polyurea coating, increases the impact resistance of aramid polyurea composite material, improves the bulletproof performance of the composite material fabric, and the softness and air permeability of the aramid polyurea composite material fabric are also improved, and the comfort is improved; the bulletproof performance of the fabric can be significantly improved by using 10%-20% glycidyl methacrylate, and the aramid polyurea composite material fabric can maximize the ergonomics performance while ensuring the bulletproof performance. DETAILED DESCRIPTION

[0032] To make the purpose, technical scheme and advantages of the application clearer, the application is further described in detail below in combination with embodiments. Herein, the illustrative embodiments of the application and the description thereof are used to explain the application, but not as a limitation of the application.

[0033] The preparation method of the bulletproof aramid polyurea composite material based on ultraviolet modification comprises the following steps:

[0034] S1, fiber pretreatment, removing aramid surface impurities,

[0035] S2, ultraviolet modification of aramid, increasing surface roughness,

[0036] S3, preparation of polyurea coating, comprising the following steps:

[0037] S31, stirring aldehyde compound and mercapto compound in water solvent until the viscosity no longer increases, to obtain aldehyde-terminated polyhemithioacetal precursor,

[0038] S32, stirring isocyanate compound and amino compound in water solvent until the viscosity no longer increases, to obtain amino-terminated polyurea precursor,

[0039] S33, mixing the solutions obtained in steps S31 and S32 with each other, stirring for 2-3 hours, and curing in a drying oven at 80-88°C for 24-36 hours to obtain a polyurea coating material,

[0040] S4, spraying the polyurea coating material prepared in step S3 onto the modified aramid fiber material obtained in step S2, with a spraying thickness of 1.5-2 mm, to obtain an aramid polyurea composite fabric.

[0041] In one embodiment, step S2 comprises the steps of:

[0042] S21, preparing a photoinitiator with acetone as a solvent and benzophenone as a solute,

[0043] S22, adding glycidyl methacrylate with a mass fraction of 2.5%-20% to the photoinitiator solution,

[0044] S23, immersing aramid fibers into the mixed solution obtained in step S22, purging the solution with pure nitrogen for 5-10 min to eliminate oxygen, and irradiating with ultraviolet light of 300-400 mm under a 500V high-pressure mercury lamp at room temperature for 10-30 min,

[0045] S24, taking out the aramid fibers obtained in step S23, washing with ethanol and distilled water for more than three times to remove physically absorbed monomers or homopolymers, and drying in a vacuum oven for 10-13 h at an oven temperature of 90-100°C.

[0046] In one embodiment, the mass fraction of the photoinitiator prepared in step S21 is 2.5%.

[0047] In one embodiment, the ultraviolet irradiation time in step S23 is 15 min.

[0048] In one embodiment, the drying time in step S24 is 12 h.

[0049] In one embodiment, in step S31, the mass ratio of the aldehyde compound to the mercapto compound is 1:1.2-1.5; and in step S32, the mass ratio of the isocyanate compound to the amino compound is 1:3.2-3.7.

[0050] In one embodiment, in step S31, the aldehyde compound is triformylphloroglucinol, and the mercapto compound is bis(3-mercaptopropionate)glycol, with a mass ratio of 1:1.4; and in step S33, the isocyanate compound is phenylene dimethylene diisocyanate, and the amino compound is amino-terminated polytetrahydrofuran, with a mass ratio of 1:3.6.

[0051] In one embodiment, step S1 comprises the steps of:

[0052] S11, placing aramid fibers in anhydrous ethanol solution for ultrasonic cleaning for 20-30 min, the ultrasonic temperature is 20-30℃, and the surface oil stains and impurities are removed by ultrasonic immersion,

[0053] S12, placing the cleaned aramid fibers in a vacuum oven for drying for 4-6h, and the vacuum drying temperature is 90-100℃.

[0054] In one embodiment, the concentration of the anhydrous ethanol solution used in step S11 is 99.5%.

[0055] The bulletproof aramid polyurea composite material based on ultraviolet modification is prepared by the above preparation method.

[0056] Example 1: bulletproof aramid polyurea composite material based on ultraviolet modification, the preparation steps are as follows:

[0057] S1, fiber pretreatment, removing aramid surface impurities, step S1 includes the following steps:

[0058] S11, placing aramid fibers in anhydrous ethanol solution for ultrasonic cleaning for 20 min, the ultrasonic temperature is 20℃, and the surface oil stains and impurities are removed by ultrasonic immersion,

[0059] S12, placing the cleaned aramid fibers in a vacuum oven for drying for 4h, and the vacuum drying temperature is 90℃,

[0060] S2, ultraviolet modification of aramid, increasing surface roughness, step S2 includes the following steps:

[0061] S21, preparing a photoinitiator with acetone as a solvent and benzophenone as a solute,

[0062] S22, adding glycidyl methacrylate with a mass fraction of 2.5% to the photoinitiator solution,

[0063] S23, immersing aramid fibers in the mixed solution obtained in step S22, purging the solution with pure nitrogen for 5 min to eliminate oxygen, irradiating with 300-400mm ultraviolet light under a 500V high-pressure mercury lamp at room temperature for 10 min,

[0064] S24, taking out the aramid fibers obtained in step S23, washing with ethanol and distilled water for more than three times to remove physically absorbed monomers or homopolymers, and drying in a vacuum oven for 13h, and the oven temperature is 90℃,

[0065] S3, preparation of polyurea coating, including the following steps:

[0066] S31, stirring the aldehyde compound and the mercapto compound in a water solvent at a mass ratio of 1:1.2 until the viscosity no longer increases, to obtain an aldehyde group terminated polyhemithioacetal precursor,

[0067] S32, stirring the isocyanate compound and the amino compound in a water solvent at a mass ratio of 1:3.2 until the viscosity no longer increases, to obtain an amino group terminated polyurea precursor,

[0068] S33, mixing the solutions obtained in steps S31 and S32 with each other, the solvent and the mixed substances at a mass ratio of 1:1-2, stirring for 3 hours, and solidifying in a drying oven at 80°C for 36 hours, to obtain a polyurea coating material,

[0069] S4, spraying the polyurea coating material prepared in step S3 onto the modified aramid fiber material obtained in step S2, the spraying thickness being 1.5-2 mm, wherein the sample surface density gain does not exceed 10%, to obtain an aramid polyurea composite fabric.

[0070] The sprayed aramid fabric is characterized, and compared with the conventional aramid material fabric directly sprayed with polyurea, the modified polyurea aramid composite fabric has an increased ballistic limit speed of 9.8%, an increased softness of 2.2%, and an increased air permeability of 9.3%.

[0071] Example 2: UV-modified bulletproof aramid polyurea composite material, the preparation steps being as follows:

[0072] S1, fiber pretreatment, removing impurities on the surface of aramid, step S1 including steps:

[0073] S11, placing the type 1414 aramid fiber in a concentrated 99.5% ethanol solution for ultrasonic cleaning for 30 min, the ultrasonic temperature being 25°C, and removing the surface oil stains and impurities through ultrasonic immersion,

[0074] S12, drying the cleaned aramid fiber in a vacuum oven for 6 h, the vacuum drying temperature being 95°C, and the anhydrous ethanol being gasified at high temperature without affecting the subsequent experimental structure,

[0075] S2, UV-modified aramid, increasing the surface roughness, step S2 including steps:

[0076] S21, preparing a photoinitiator with a mass fraction of 2.5% by taking acetone as a solvent and benzophenone as a solute,

[0077] S22, adding glycidyl methacrylate with a mass fraction of 5% to the photoinitiator solution,

[0078] S23, the aramid fiber is immersed in the mixed solution obtained in step S22, and the solution is purged with pure nitrogen for 10 min to eliminate oxygen, and the solution is irradiated with ultraviolet light of 300-400 mm under a 500 V high-pressure mercury lamp at room temperature for 20 min,

[0079] S24, the aramid fiber obtained in step S23 is taken out, washed with ethanol and distilled water for more than three times to remove the physically absorbed monomer or homopolymer, and dried in a vacuum oven for 12 h at an oven temperature of 100℃,

[0080] S3, preparation of polyurea coating, including the following steps:

[0081] S31, the aldehyde group terminated polyhemithioacetal precursor is obtained by stirring the tri-aldehyde group phloroglucinol and bis(3-mercapto propionate) ethylene glycol in a water solvent at a mass ratio of 1:1.5 until the viscosity no longer increases,

[0082] S32, the amino-terminated polyurea precursor is obtained by stirring the benzene dimethylene diisocyanate and amino-terminated polytetrahydrofuran in a water solvent at a mass ratio of 1:3.7 until the viscosity no longer increases,

[0083] S33, the solutions obtained in steps S31 and S32 are mixed with each other, the solvent and the mixed substances are at a mass ratio of 1:1-2, and the stirring reaction is carried out for 2 h, and the solidification is carried out in a drying oven at 88℃ for 30 h to obtain a polyurea coating material,

[0084] S4, the polyurea coating material prepared in step S3 is sprayed onto the modified aramid fiber material obtained in step S2, the spraying thickness is 1.5-2 mm, wherein the sample surface density gain does not exceed 10%, and an aramid polyurea composite fabric is obtained.

[0085] The modified aramid fabric is characterized, and it is found that the surface is rougher and can better combine with the polyurea coating. Compared with the traditional aramid material fabric directly sprayed with polyurea, the ballistic limit speed of the modified polyurea aramid composite fabric is increased by 20.6%, the softness is increased by 2.2%, and the air permeability is increased by 8.1%.

[0086] Example 3: ultraviolet modified anti-ballistic aramid polyurea composite material, the preparation steps are as follows:

[0087] S1, fiber pretreatment, removing surface impurities of aramid, step S1 includes the following steps:

[0088] S11, the 1414 type aramid fiber is placed in a 99.5% concentrated anhydrous ethanol solution and ultrasonically cleaned for 25 min, the ultrasonic temperature is 30℃, and the surface oil impurities are removed by ultrasonic immersion,

[0089] S12, the cleaned aramid fiber is placed in a vacuum oven for drying for 5 h, the vacuum drying temperature is 100 DEG C, and the anhydrous ethanol is high-temperature gasification, which does not affect the subsequent experimental structure,

[0090] S2, the aramid fiber is modified by ultraviolet rays to increase the surface roughness, and step S2 comprises the following steps:

[0091] S21, an initiator is prepared by using acetone as a solvent and benzophenone as a solute, and the mass fraction of the initiator is 2.5%,

[0092] S22, glycidyl methacrylate with a mass fraction of 15% is added to the initiator solution,

[0093] S23, the aramid fiber is immersed in the mixed solution obtained in step S22, and the solution is purged with pure nitrogen for 5 min to eliminate oxygen, and the aramid fiber is irradiated with ultraviolet rays with a wavelength of 300-400 mm under a 500 V high-voltage mercury lamp at room temperature for 25 min,

[0094] S24, the aramid fiber obtained in step S23 is taken out, washed with ethanol and distilled water for more than three times to remove the physically absorbed monomer or homopolymer, and dried in a vacuum oven for 10 h, and the oven temperature is 100 DEG C,

[0095] S3, preparation of a polyurea coating, comprising the following steps:

[0096] S31, tri-aldehyde-based phloroglucinol and bis(3-mercapto propionate) ethylene glycol are stirred in a water solvent at a mass ratio of 1:1.4 until the viscosity no longer increases, to obtain an aldehyde-terminated polyhemithioacetal precursor,

[0097] S32, phenylenedimethylene diisocyanate and amino-terminated polytetrahydrofuran are stirred in a water solvent at a mass ratio of 1:3.6 until the viscosity no longer increases, to obtain an amino-terminated polyurea precursor,

[0098] S33, the solutions obtained in steps S31 and S32 are mixed with each other, the solvent and the mixed substances are mixed at a mass ratio of 1:1-2, and the mixture is stirred for 2 h, and then solidified in a drying oven at 85 DEG C for 24 h to obtain a polyurea coating material,

[0099] S4, the polyurea coating material prepared in step S3 is sprayed onto the modified aramid fiber material obtained in step S2, the spraying thickness is 1.5-2 mm, and the sample surface density gain is not more than 10%, to obtain an aramid polyurea composite fabric.

[0100] The modified aramid fabric is characterized, and it is found that the surface is rougher and can better combine with the polyurea coating. Compared with the traditional direct spraying of polyurea on the aramid fabric, the ballistic limit speed of the modified polyurea aramid composite fabric is increased by 26.3%, the softness is increased by 1.1%, and the air permeability is increased by 6.2%.

[0101] Example 4: UV-modified bulletproof aramid polyurea composite material, the preparation steps are as follows:

[0102] S1, fiber pretreatment, remove the impurities on the surface of aramid, step S1 includes the following steps:

[0103] S11, place the 1414 type aramid fiber in a 99.5% concentrated ethanol solution and ultrasonic clean for 30 min, the ultrasonic temperature is 25℃, the surface oil impurities are removed by ultrasonic immersion,

[0104] S12, place the cleaned aramid fiber in a vacuum oven and dry for 6h, the vacuum drying temperature is 95℃, the anhydrous ethanol will be gasified at high temperature, which does not affect the subsequent experimental structure,

[0105] S2, UV-modified aramid, increase the surface roughness, step S2 includes the following steps:

[0106] S21, prepare a photoinitiator with a mass fraction of 2.5% using acetone as a solvent and benzophenone as a solute,

[0107] S22, add glycidyl methacrylate with a mass fraction of 20% to the photoinitiator solution,

[0108] S23, immerse the aramid fiber in the mixed solution obtained in step S22, and blow the solution with pure nitrogen for 5 min to eliminate oxygen, irradiate with 300-400mm ultraviolet light under a 500V high-pressure mercury lamp at room temperature for 30 min,

[0109] S24, take out the aramid fiber obtained in step S23, wash it with ethanol and distilled water more than three times to remove physically absorbed monomers or homopolymers, and dry it in a vacuum oven for 10h at an oven temperature of 95℃,

[0110] S3, preparation of polyurea coating, including the following steps:

[0111] S31, stir tri-aldehyde-based phloroglucinol and bis(3-mercaptopropionate) ethylene glycol in a water solvent at a mass ratio of 1:1.4 until the viscosity no longer increases, to obtain an aldehyde-terminated polyhemithioacetal precursor,

[0112] S32, stirring benzene dimethylene diisocyanate and amino-terminated polytetrahydrofuran in a water solvent at a mass ratio of 1:3.6 until the viscosity no longer increases, to obtain an amino-terminated polyurea precursor,

[0113] S33, mixing the solutions obtained in steps S31 and S32 with each other, stirring the mixture for 2 hours at a solvent and mixture mass ratio of 1:1-2, and solidifying in a drying oven at 85°C for 24 hours to obtain a polyurea coating material,

[0114] S4, spraying the polyurea coating material prepared in step S3 onto the modified aramid fiber material obtained in step S2, with a spraying thickness of 1.5-2 mm, wherein the sample surface density gain does not exceed 10%, to obtain an aramid polyurea composite fabric.

[0115] The modified aramid fabric was characterized, and it was found that the surface was rougher and could better combine with the polyurea coating. Compared with the traditional aramid material fabric directly sprayed with polyurea, the ballistic limit speed of the modified polyurea aramid composite fabric was increased by 36.2%, the softness was increased by 1.1%, and the air permeability was increased by 5.0%.

[0116] Comparative Example: The aramid polyurea composite fabric was prepared as follows,

[0117] S1, placing aramid fibers in an ethanol solution and ultrasonically cleaning for 30 min,

[0118] S2, drying the cleaned aramid fibers in a vacuum oven for 6 h,

[0119] S3, mixing and stirring isocyanate and amino-terminated polyether at a ratio of 1.1:1, and drying and curing at room temperature for 72 hours to form a polyurea coating material,

[0120] S4, spraying the polyurea coating material obtained in step S3 into the aramid fiber material obtained in step S2, with a spraying thickness of 1.5-2 mm, wherein the sample surface density gain does not exceed 10%, to obtain an aramid polyurea composite fabric.

[0121] The ballistic limit speed, softness, and air permeability of Examples 1-4 and the comparative example were tested, and the results are shown in Table 1.

[0122] Related descriptions of ballistic limit speed, softness, and air permeability:

[0123] Fiber fabric ballistic limit test method: high pressure ballistic impact device is used for testing, the bullet used for ballistic impact is a spherical steel ball with a diameter of 5 mm, the bullet power is mainly obtained from high pressure gas in the gas storage tank, the high pressure gas pressure is changed to obtain the bullet incident speed of 40-300 m / s. A high-speed photography equipment is used in the experiment, which mainly records and measures the instantaneous speed before and after the bullet impact, and calculates the ballistic limit speed V 50 of the experimental sample according to the incident speed and residual speed. The target plate has an outer size of 18*18 cm and an inner window size of 16*16 cm, is fixed at four corners, and a stainless steel frame is selected to clamp the four corners of the sample.

[0124] Fiber fabric softness test: a certain size of fiber fabric long sample is used as a cantilever beam, and the length, bending stiffness and bending modulus when bending are calculated according to its flexibility, which are used as indexes of fabric softness. The greater the bending length value, the stiffer the fabric and the less likely to bend.

[0125] Fiber fabric air permeability test: the differential pressure method is used for testing principle, the pre-processed sample is placed between the upper and lower test cavities and clamped. First, the low pressure cavity, i.e. the lower cavity, is vacuum treated, then the whole system is vacuumed, when the specified vacuum degree is reached, the test lower cavity is closed, a certain pressure test gas is filled into the high pressure cavity, and a constant is ensured on both sides of the sample, so that the barrier parameters of the tested sample are obtained.

[0126] Comparing between examples 1-4 and the comparative example, it can be found that with the increase of the concentration of the modified raw material, the modified aramid fiber fabric can better combine with the polyurea coating layer to form a new type of polyurea aramid composite fabric, which can greatly improve the impact resistance and bullet resistance of the fabric. It is found that the softness of examples 1-4 is slightly improved compared with the comparative example by using the overhanging method to test the softness; according to the air permeability test of GB / T5453-1997, it can be found that the air permeability is effectively improved compared with the comparative example.

[0127] Table 1 test performance results of examples 1-4 and the comparative example

[0128]

[0129] The above is only the preferred embodiment of the present application, not other forms of the present application, any skilled person in the art can use the above disclosed technical content to make changes or modifications into equivalent examples with equivalent changes. However, any simple modification, equivalent change and modification made on the above examples according to the technical essence of the present application without departing from the technical solution content of the present application still belongs to the protection scope of the present application.

Claims

1. A method for preparing an ultraviolet-modified aramid polyurea composite material for bulletproof, characterized in that, The method comprises the steps of: S1, pretreatment of the fiber, removing impurities on the surface of aramid fiber, step S1 comprising the following steps: S11, placing aramid fiber in anhydrous ethanol solution for ultrasonic cleaning for 20-30 min, the ultrasonic temperature is 20-30℃, and the concentration of anhydrous ethanol solution is 99.5%; S12, placing the cleaned aramid fiber in a vacuum oven for drying for 4-6h, and the vacuum drying temperature is 90-100℃; S2, ultraviolet modification of aramid, increasing the surface roughness, step S2 comprising the following steps: S21, preparing a photoinitiator with acetone as a solvent and benzophenone as a solute; S22, adding glycidyl methacrylate with a mass fraction of 2.5%-20% to the photoinitiator solution; S23, immersing aramid fiber into the mixed solution obtained in step S22, purging the solution with pure nitrogen for 5-10 min, and irradiating with 300-400 mm ultraviolet light under a 500 V high-pressure mercury lamp at room temperature for 10-30 min; S24, taking out the aramid fiber obtained in step S23, washing it with ethanol and distilled water for more than three times, and drying it in a vacuum oven for 10-13h, and the oven temperature is 90-100℃; S3, preparation of polyurea coating, comprising the following steps: S31, stirring aldehyde compound and mercapto compound in an aqueous solvent until the viscosity no longer increases to obtain an aldehyde-terminated polyhemithioacetal precursor, the aldehyde compound is triformylphloroglucinol, the mercapto compound is bis(3-mercaptopropionate)glycol, and the mass ratio is 1:1.4; the mass ratio of aldehyde compound to mercapto compound is 1:1.2-1.5; S32, stirring isocyanate compound and amino compound in an aqueous solvent until the viscosity no longer increases to obtain an amino-terminated polyurea precursor, the isocyanate compound is xylylene diisocyanate, and the amino compound is amino-terminated polytetrahydrofuran, and the mass ratio is 1:3.6; S33, mixing the solutions obtained in steps S31 and S32, stirring for 2-3 hours, and curing in a drying oven at 80-88℃ for 24-36 hours to obtain a polyurea coating material; S4, spraying the polyurea coating material prepared in step S3 onto the modified aramid fiber material obtained in step S2, and the spraying thickness is 1.5-2 mm to obtain an aramid polyurea composite fabric.

2. The method for preparing the UV-modified bulletproof aramid polyurea composite material according to claim 1, characterized in that, The mass fraction of the photoinitiator prepared in step S21 is 2.5%.

3. The method for preparing the UV-modified bulletproof aramid polyurea composite material according to claim 1, characterized in that, The ultraviolet irradiation time in step S23 is 15 min.

4. The method for preparing the UV-modified bulletproof aramid polyurea composite material according to claim 1, characterized in that, The drying time in step S24 is 12h.

5. Bulletproof aramid polyurea composite based on ultraviolet modification, characterized by that, The aramid polyurea composite fabric is prepared by the method for preparing an ultraviolet-modified bulletproof aramid polyurea composite material according to any one of claims 1-4.

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