Preparation technology of modified ultra-high molecular weight polyethylene fiber for bulletproof vests

Abstract

The present invention discloses a preparation process of modified ultra-high molecular weight bulletproof polyethylene fiber, comprising the following steps: S1. preparing a spinning composite raw material, S2. preparing a swelling suspension, S3. preparing a spinning fluid, S4. preparing an ultra-high molecular weight bulletproof polyethylene fiber, S5. first preparing a single UD cloth from the ultra-high molecular weight polyethylene fiber, and then making a plurality of single UD cloths into a laminate, and conducting a ballistic performance test. Under the premise of considering performance degradation, the present invention reduces the total input of ultra-high molecular weight polyethylene by mixing an elastomer with ultra-high molecular weight polyethylene micropowder, and also ensures the performance of the ultra-high molecular weight polyethylene fiber; by blending and modifying ultra-high molecular weight polyethylene and polyimide, the back bulge BFS value is effectively suppressed without affecting the fiber absorption energy SEA value, and the ballistic performance is improved; it is more reasonable to judge the performance of the modified ultra-high molecular weight polyethylene fiber by testing the laminate.

Description

Technical Field

[0001] The invention relates to the technical field of bulletproof vest production, and more specifically, to a preparation process of modified ultra-high molecular weight bulletproof vest polyethylene fiber. Background Art

[0002] High-end ultra-high molecular weight polyethylene fiber is the most basic and core part of bulletproof materials. The global ultra-high molecular weight polyethylene fiber product technology and production capacity are developing rapidly, and the demand is also rising. The bulletproof materials based on high-end ultra-high molecular weight polyethylene fiber and the core have continuously improved their product performance, the technical level has been continuously improved, and the market demand has been steadily growing.

[0004] Whether from a national strategic perspective or simply in terms of material costs, it is urgent to use less ultra-high molecular weight polyethylene fiber to produce bulletproof vests of similar or better quality. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a process for preparing modified ultra-high molecular weight polyethylene fiber for bulletproof vests to solve one or more of the above-mentioned problems.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The preparation process of modified ultra-high molecular weight bulletproof polyethylene fiber comprises the following steps:

[0008] S1. Preparation of a spinning composite material: A mixture of elastomers A and B and ultra-high molecular weight polyethylene powder are mixed to obtain a spinning composite material;

[0009] S2. Preparation of a swelling suspension: Adding an emulsifier and an antioxidant to the spinning composite raw material obtained in step S1, stirring and heating in a swelling reactor to obtain a swelling suspension;

[0010] S3. Preparation of spinning fluid: The swollen suspension is added with a modifying liquid under high temperature and high pressure to complete the blending modification to obtain a spinning fluid;

[0011] S4. Preparation of ultra-high molecular weight polyethylene fiber for bulletproof vests: The spinning fluid is sequentially subjected to extrusion, spinning, spinning, extraction, drying, heating, stretching and winding to form ultra-high molecular weight polyethylene fiber;

[0012] S5. The ultra-high molecular weight polyethylene fiber obtained in step S4 is firstly made into a single UD cloth through a wet process, and then a plurality of single UD cloths are made into a laminate, and the obtained laminate is tested for its ballistic performance.

[0013] Further, the component of the elastomer A in step S1 is 4,4' diphenylmethane diisocyanate polyether polyurethane prepolymer;

[0014] The component of elastomer B is a mixture of amino-terminated polyether and amino-terminated chain extender;

[0015] The mixing amount of ultra-high molecular weight polyethylene powder is 13-18wt% of the total mass of the elastomer A and B mixed materials.

[0016] Furthermore, in step S2, the emulsifier is selected from one or more of fatty alcohol polyoxyethylene polyoxypropylene ether, dodecyl phosphate monoester, fatty alcohol polyoxyethylene ether, and ethylenediaminetetraacetic acid;

[0017] The antioxidant is selected from one or more of dioctyl phthalate, triphenyl phosphite, and butylated hydroxytoluene;

[0018] The swelling temperature is 85-100°C, the stirring speed is 72-115 r / min, and the swelling time is 1-1.5 h.

[0019] Furthermore, in step S3, the high temperature and high pressure environment refers to 195-270°C, 2-50MPa, and the heating rate is 5°C / min;

[0020] The modified liquid is a polyimide solution after thermal imidization at 195-200°C.

[0021] Furthermore, in the extrusion process in step S4, the spinning fluid is first cooled to 85-90°C and degassed by physical vibration, and then passed through a screw extruder to complete extrusion granulation at a feed section of 90-110°C, a compression section of 105-145°C, a metering section of 140-163°C, and a rotation speed of 70-120 r / min, with a granulation diameter of 4-10 mm;

[0022] The spinning process in step S4: the granulation is evenly distributed at 150-160°C;

[0023] The spinning process in step S4: the material is extruded into filaments through a spinneret by a metering pump, and the spinning speed is 320-950 m / min;

[0024] The heating and stretching in step S4 is divided into four stages, the temperatures of the five groups of hot rollers are all 50-105° C., and the total stretching times are 20-40.

[0025] Furthermore, polytetrafluoroethylene cloth and silicone oil are sequentially laid on the prepared mold, and the ultra-high molecular weight polyethylene fiber obtained in step S4 is wound along the mold surface and coated with polyimide resin, and the resin content is controlled to be 15wt% of the mass of the single UD cloth finished product, and the density of the single UD cloth is 60±5g / m 2, and place it at room temperature to cure for 45 to 90 hours to obtain a single UD cloth product.

[0026] Furthermore, before the ballistic performance test in step S5, the obtained single UD cloth is cut into single pieces of 300 mm x 300 mm with electric scissors, and the single pieces are laid out into laminates in a 0° / 90° alternating plying manner, and the laminates are placed in a hot pressing mold and sent into a hot pressing machine, and kept warm for 30 minutes under the conditions of a pressure of 1 MPa and a temperature of 128°C, and the laminates are taken out after the pressure is maintained and the temperature is lowered, and the laminates are cured at room temperature and pressure for 168 hours.

[0027] Furthermore, the ballistic limit velocity V50 value and BFS of the treated single UD cloth laminate were tested;

[0028] Ballistic limit velocity V50 value test: projecting 5.6g, 7.62mm lead core bullets at a launch distance of 5m, the V50 value is obtained by correcting the results of multiple bullet velocities with similar numbers of penetrations and non-penetrations;

[0029] BFS test: Control the initial velocity of the bullet to 445±10m / s, use a depth gauge with an accuracy of 0.01mm to measure, and take the average value of the bullet hole depth of 6 bullets as the BFS value.

[0030] Furthermore, according to the formula

[0031]

[0032] Where SEA is the absorbed energy of the laminate (J·m 2 / kg), m p is the mass of the lead core bullet (kg), V50 is the limiting velocity of the laminate (m / s), AD is the density of the laminate (kg / m 2 ).

[0033] Furthermore, in step S1, the mixing mass ratio of elastomer A to elastomer B is 0.72-0.89:1.

[0034] In summary, the present invention has the following beneficial effects:

[0035] 1. Under the premise of considering the performance degradation, the total input of ultra-high molecular weight polyethylene is reduced by mixing the elastomer with ultra-high molecular weight polyethylene powder, and the performance of ultra-high molecular weight polyethylene fiber is also guaranteed;

[0036] 2. Through the blending modification of ultra-high molecular weight polyethylene and polyimide, the back bulge BFS value is effectively suppressed without affecting the fiber absorption energy SEA value, thereby improving the ballistic performance;

[0037] 3. It is more reasonable to judge the performance of modified ultra-high molecular weight polyethylene fiber by testing the laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A process flow chart of an embodiment of the present invention;

[0039] Figure 2 A production line structure diagram of an embodiment of the present invention;

[0040] Figure 3 A microscopic diagram of ballistic test results according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following is combined with Figure 1-3 The present invention is described in further detail.

[0042] Embodiment 1:

[0043] The preparation process of modified ultra-high molecular weight polyethylene fiber for bulletproof vests, such as Figure 1 and Figure 2 As shown, the following steps are included:

[0044] S1. Preparation of a spinning composite material: A mixture of elastomers A and B and ultra-high molecular weight polyethylene powder are mixed to obtain a spinning composite material;

[0045] The component of the elastomer A in step S1 is 4,4' diphenylmethane diisocyanate polyether polyurethane prepolymer;

[0046] The component of elastomer B is a mixture of amino-terminated polyether and amino-terminated chain extender;

[0047] The amount of ultra-high molecular weight polyethylene powder added is 13wt% of the total mass of the elastomer A and B mixture;

[0048] The mixing mass ratio of elastomer A to elastomer B in step S1 is 0.72:1.

[0049] S2. Preparation of a swelling suspension: Adding an emulsifier and an antioxidant to the spinning composite raw material obtained in step S1, stirring and heating in a swelling reactor to obtain a swelling suspension;

[0050] In step S2, the emulsifier is selected from one or more of fatty alcohol polyoxyethylene polyoxypropylene ether, dodecyl phosphate monoester, fatty alcohol polyoxyethylene ether, and ethylenediaminetetraacetic acid;

[0051] The antioxidant is selected from one or more of dioctyl phthalate, triphenyl phosphite, and butylated hydroxytoluene;

[0052] The swelling temperature was 85°C, the stirring speed was 72 r / min, and the swelling time was 1 h.

[0053] S3. Preparation of spinning fluid: The swollen suspension is added with a modifying liquid under high temperature and high pressure to complete the blending modification to obtain a spinning fluid;

[0054] In step S3, the high temperature and high pressure environment refers to 195°C, 2MPa, and the heating rate is 5°C / min;

[0055] The modified liquid is a polyimide solution after thermal imidization at 195°C;

[0056] The modification in step S3 can make the ultra-high molecular weight polyethylene have additional high temperature resistance and high modulus properties, forming a complementary relationship.

[0057] S4. Preparation of ultra-high molecular weight polyethylene fiber for bulletproof vests: The spinning fluid is sequentially subjected to extrusion, spinning, spinning, extraction, drying, heating, stretching and winding to form ultra-high molecular weight polyethylene fiber;

[0058] The extrusion process in step S4: firstly cool the spinning fluid to 85°C and degas by physical vibration, and then pass through the screw extruder to complete extrusion granulation at a speed of 70r / min in the range of 90°C in the feeding section, 105°C in the compression section, 140°C in the metering section, and a granulation diameter of 4mm;

[0059] The spinning process in step S4: the granulation is evenly distributed at 150°C;

[0060] Spinning process in step S4: the material is extruded into filaments through the spinneret by a metering pump, and the spinning speed is 320 m / min;

[0061] The heating and stretching in step S4 is divided into four stages, the temperature of the five groups of hot rollers are all 50° C., and the total stretching times is 20.

[0062] S5. The ultra-high molecular weight polyethylene fiber obtained in step S4 is first prepared into a single UD cloth by a wet process, and then a plurality of single UD cloths are made into a laminate, and the obtained laminate is subjected to a ballistic performance test;

[0063] Preparation of single UD cloth in step S5: laying polytetrafluoroethylene cloth and silicone oil on the prepared mold in sequence, winding the ultra-high molecular weight polyethylene fiber obtained in step S4 along the surface of the mold and coating it with polyimide resin, controlling the resin content to 15wt% of the finished single UD cloth mass, and the density of the single UD cloth to 60±5g / m 2 , placed in a room temperature environment to cure for 45 hours, and obtain a single UD cloth finished product;

[0064] Before the ballistic performance test in step S5, the obtained single UD cloth is cut into single pieces of 300 mm x 300 mm with electric scissors, and five single pieces are laid out as a laminate in a 0° / 90° alternating laying manner, and the laminate is placed in a hot pressing mold and sent into a hot pressing machine, and kept warm for 30 minutes under the conditions of a pressure of 1 MPa and a temperature of 128° C., and the laminate is taken out after the pressure is maintained and the temperature is lowered, and the laminate is cured at room temperature and pressure for 168 hours;

[0065] The treated single UD cloth laminate was tested for ballistic limit velocity V50 value and BFS;

[0066] Ballistic limit velocity V50 value test: projecting 5.6g, 7.62mm lead core bullets at a launch distance of 5m, the V50 value is obtained by correcting the results of multiple bullet velocities with similar numbers of penetrations and non-penetrations;

[0067] BFS test: Control the initial velocity of the bullet to 445±10m / s, use a depth gauge with an accuracy of 0.01mm to measure, and take the average value of the bullet hole depth of 6 bullets as the BFS value.

[0068] According to the formula

[0069]

[0070] Where SEA is the absorbed energy of the laminate (J·m 2 / kg), m p is the mass of the lead core bullet (kg), V50 is the limiting velocity of the laminate (m / s), AD is the density of the laminate (kg / m 2 ).

[0071] Example 2

[0072] The preparation process of modified ultra-high molecular weight bulletproof polyethylene fiber comprises the following steps:

[0073] S1. Preparation of a spinning composite material: A mixture of elastomers A and B and ultra-high molecular weight polyethylene powder are mixed to obtain a spinning composite material;

[0074] The component of the elastomer A in step S1 is 4,4' diphenylmethane diisocyanate polyether polyurethane prepolymer;

[0075] The component of elastomer B is a mixture of amino-terminated polyether and amino-terminated chain extender;

[0076] The amount of ultra-high molecular weight polyethylene powder added is 18wt% of the total mass of the mixture of elastomers A and B;

[0077] The mixing mass ratio of elastomer A to elastomer B in step S1 is 0.89:1.

[0078] S2. Preparation of a swelling suspension: Adding an emulsifier and an antioxidant to the spinning composite raw material obtained in step S1, stirring and heating in a swelling reactor to obtain a swelling suspension;

[0079] In step S2, the emulsifier is selected from one or more of fatty alcohol polyoxyethylene polyoxypropylene ether, dodecyl phosphate monoester, fatty alcohol polyoxyethylene ether, and ethylenediaminetetraacetic acid;

[0080] The antioxidant is selected from one or more of dioctyl phthalate, triphenyl phosphite, and butylated hydroxytoluene;

[0081] The swelling temperature was 100°C, the stirring speed was 115 r / min, and the swelling time was 1.5 h.

[0082] S3. Preparation of spinning fluid: The swollen suspension is added with a modifying liquid under high temperature and high pressure to complete the blending modification to obtain a spinning fluid;

[0083] In step S3, the high temperature and high pressure environment refers to 270°C, 50MPa, and the heating rate is 5°C / min;

[0084] The modified liquid is a polyimide solution after thermal imidization at 200°C;

[0085] The modification in step S3 can make the ultra-high molecular weight polyethylene have additional high temperature resistance and high modulus properties, forming a complementary relationship.

[0086] S4. Preparation of ultra-high molecular weight polyethylene fiber for bulletproof vests: The spinning fluid is sequentially subjected to extrusion, spinning, spinning, extraction, drying, heating, stretching and winding to form ultra-high molecular weight polyethylene fiber;

[0087] The extrusion process in step S4: firstly cool the spinning fluid to 90°C and degas by physical vibration, and then pass through the screw extruder to complete extrusion granulation at a speed of 120r / min in the range of 110°C in the feeding section, 145°C in the compression section, 163°C in the metering section, and a granulation diameter of 10mm;

[0088] The spinning process in step S4: the granulation is evenly distributed at 160°C;

[0089] Spinning process in step S4: the material is extruded into filaments through a spinneret by a metering pump, and the spinning speed is 950 m / min;

[0090] The heating and stretching in step S4 is divided into four stages, the temperature of the five groups of hot rollers are all 105° C., and the total stretching ratio is 40.

[0091] S5. The ultra-high molecular weight polyethylene fiber obtained in step S4 is first prepared into a single UD cloth by a wet process, and then a plurality of single UD cloths are made into a laminate, and the obtained laminate is subjected to a ballistic performance test;

[0092] Preparation of single UD cloth in step S5: laying polytetrafluoroethylene cloth and silicone oil on the prepared mold in sequence, winding the ultra-high molecular weight polyethylene fiber obtained in step S4 along the surface of the mold and coating it with polyimide resin, controlling the resin content to 15wt% of the finished single UD cloth mass, and the density of the single UD cloth to 60±5g / m 2 , placed in a room temperature environment to cure for 90 hours, and obtain a single UD cloth finished product;

[0093] Before the ballistic performance test in step S5, the obtained single UD cloth is cut into single pieces of 300 mm x 300 mm with electric scissors, and five single pieces are laid out as a laminate in a 0° / 90° alternating laying manner, and the laminate is placed in a hot pressing mold and sent into a hot pressing machine, and kept warm for 30 minutes under the conditions of a pressure of 1 MPa and a temperature of 128° C., and the laminate is taken out after the pressure is maintained and the temperature is lowered, and the laminate is cured at room temperature and pressure for 168 hours;

[0094] The treated single UD cloth laminate was tested for ballistic limit velocity V50 value and BFS;

[0095] Ballistic limit velocity V50 value test: projecting 5.6g, 7.62mm lead core bullets at a launch distance of 5m, the V50 value is obtained by correcting the results of multiple bullet velocities with similar numbers of penetrations and non-penetrations;

[0096] BFS test: Control the initial velocity of the bullet to 445±10m / s, use a depth gauge with an accuracy of 0.01mm to measure, and take the average value of the bullet hole depth of 6 bullets as the BFS value.

[0097] According to the formula

[0098]

[0099] Where SEA is the absorbed energy of the laminate (J·m 2 / kg), m p is the mass of the lead core bullet (kg), V50 is the limiting velocity of the laminate (m / s), AD is the density of the laminate (kg / m 2 ).

[0100] Example 3

[0101] The preparation process of modified ultra-high molecular weight bulletproof polyethylene fiber comprises the following steps:

[0102] S1. Preparation of a spinning composite material: A mixture of elastomers A and B and ultra-high molecular weight polyethylene powder are mixed to obtain a spinning composite material;

[0103] The component of the elastomer A in step S1 is 4,4' diphenylmethane diisocyanate polyether polyurethane prepolymer;

[0104] The component of elastomer B is a mixture of amino-terminated polyether and amino-terminated chain extender;

[0105] The amount of ultra-high molecular weight polyethylene powder added is 15wt% of the total mass of the elastomer A and B mixture;

[0106] The mixing mass ratio of elastomer A to elastomer B in step S1 is 0.81:1.

[0107] S2. Preparation of a swelling suspension: Adding an emulsifier and an antioxidant to the spinning composite raw material obtained in step S1, stirring and heating in a swelling reactor to obtain a swelling suspension;

[0108] In step S2, the emulsifier is selected from one or more of fatty alcohol polyoxyethylene polyoxypropylene ether, dodecyl phosphate monoester, fatty alcohol polyoxyethylene ether, and ethylenediaminetetraacetic acid;

[0109] The antioxidant is selected from one or more of dioctyl phthalate, triphenyl phosphite, and butylated hydroxytoluene;

[0110] The swelling temperature was 93°C, the stirring speed was 91 r / min, and the swelling time was 1.3 h.

[0111] S3. Preparation of spinning fluid: The swollen suspension is added with a modifying liquid under high temperature and high pressure to complete the blending modification to obtain a spinning fluid;

[0112] In step S3, the high temperature and high pressure environment refers to 233°C, 26MPa, and the heating rate is 5°C / min;

[0113] The modified liquid is a polyimide solution after thermal imidization at 198°C;

[0114] The modification in step S3 can make the ultra-high molecular weight polyethylene have additional high temperature resistance and high modulus properties, forming a complementary relationship.

[0115] S4. Preparation of ultra-high molecular weight polyethylene fiber for bulletproof vests: The spinning fluid is sequentially subjected to extrusion, spinning, spinning, extraction, drying, heating, stretching and winding to form ultra-high molecular weight polyethylene fiber;

[0116] The extrusion process in step S4: firstly cool the spinning fluid to 88°C and degas by physical vibration, and then pass through the screw extruder to complete extrusion granulation at a speed of 95r / min with a feeding section of 100°C, a compression section of 125°C, a metering section of 151°C, and a granulation diameter of 7mm;

[0117] The spinning process in step S4: the granulation is evenly distributed at 155°C;

[0118] Spinning process in step S4: the material is extruded into filaments through the spinneret by a metering pump, and the spinning speed is 635 m / min;

[0119] The heating and stretching in step S4 is divided into four stages, the temperature of the five groups of hot rollers are all 78° C., and the total stretching ratio is 30.

[0120] S5. The ultra-high molecular weight polyethylene fiber obtained in step S4 is first prepared into a single UD cloth by a wet process, and then a plurality of single UD cloths are made into a laminate, and the obtained laminate is subjected to a ballistic performance test;

[0121] Preparation of single UD cloth in step S5: laying polytetrafluoroethylene cloth and silicone oil on the prepared mold in sequence, winding the ultra-high molecular weight polyethylene fiber obtained in step S4 along the surface of the mold and coating it with polyimide resin, controlling the resin content to 15wt% of the finished single UD cloth mass, and the density of the single UD cloth to 60±5g / m 2 , placed in a room temperature environment to cure for 68 hours to obtain a single UD cloth finished product;

[0122] Before the ballistic performance test in step S5, the obtained single UD cloth is cut into single pieces of 300 mm x 300 mm with electric scissors, and five single pieces are laid out as a laminate in a 0° / 90° alternating laying manner, and the laminate is placed in a hot pressing mold and sent into a hot pressing machine, and kept warm for 30 minutes under the conditions of a pressure of 1 MPa and a temperature of 128° C., and the laminate is taken out after the pressure is maintained and the temperature is lowered, and the laminate is cured at room temperature and pressure for 168 hours;

[0123] The treated single UD cloth laminate was tested for ballistic limit velocity V50 value and BFS;

[0124] Ballistic limit velocity V50 value test: projecting 5.6g, 7.62mm lead core bullets at a launch distance of 5m, the V50 value is obtained by correcting the results of multiple bullet velocities with similar numbers of penetrations and non-penetrations;

[0125] BFS test: Control the initial velocity of the bullet to 445±10m / s, use a depth gauge with an accuracy of 0.01mm to measure, and take the average value of the bullet hole depth of 6 bullets as the BFS value.

[0126] According to the formula

[0127]

[0128] Where SEA is the absorbed energy of the laminate (J·m 2 / kg), m p is the mass of the lead core bullet (kg), V50 is the limiting velocity of the laminate (m / s), AD is the density of the laminate (kg / m 2 ).

[0129] Example 4

[0130] The preparation process of modified ultra-high molecular weight bulletproof polyethylene fiber comprises the following steps:

[0131] S1. Preparation of a spinning composite material: A mixture of elastomers A and B and ultra-high molecular weight polyethylene powder are mixed to obtain a spinning composite material;

[0132] The component of the elastomer A in step S1 is 4,4' diphenylmethane diisocyanate polyether polyurethane prepolymer;

[0133] The component of elastomer B is a mixture of amino-terminated polyether and amino-terminated chain extender;

[0134] The amount of ultra-high molecular weight polyethylene powder added is 13wt% of the total mass of the elastomer A and B mixture;

[0135] The mixing mass ratio of elastomer A to elastomer B in step S1 is 0.75:1.

[0136] S2. Preparation of a swelling suspension: Adding an emulsifier and an antioxidant to the spinning composite raw material obtained in step S1, stirring and heating in a swelling reactor to obtain a swelling suspension;

[0137] In step S2, the emulsifier is selected from one or more of fatty alcohol polyoxyethylene polyoxypropylene ether, dodecyl phosphate monoester, fatty alcohol polyoxyethylene ether, and ethylenediaminetetraacetic acid;

[0138] The antioxidant is selected from one or more of dioctyl phthalate, triphenyl phosphite, and butylated hydroxytoluene;

[0139] The swelling temperature was 88°C, the stirring speed was 90 r / min, and the swelling time was 1.2 h.

[0140] S3. Preparation of spinning fluid: The swollen suspension is added with a modifying liquid under high temperature and high pressure to complete the blending modification to obtain a spinning fluid;

[0141] In step S3, the high temperature and high pressure environment refers to 200°C, 10MPa, and the heating rate is 5°C / min;

[0142] The modified liquid is a polyimide solution after thermal imidization at 198°C;

[0143] The modification in step S3 can make the ultra-high molecular weight polyethylene have additional high temperature resistance and high modulus properties, forming a complementary relationship.

[0144] S4. Preparation of ultra-high molecular weight polyethylene fiber for bulletproof vests: The spinning fluid is sequentially subjected to extrusion, spinning, spinning, extraction, drying, heating, stretching and winding to form ultra-high molecular weight polyethylene fiber;

[0145] The extrusion process in step S4: firstly cool the spinning fluid to 85°C and degas by physical vibration, and then pass through the screw extruder to complete extrusion granulation at a speed of 90r / min with a feeding section of 100°C, a compression section of 120°C, a metering section of 150°C, and a granulation diameter of 8mm;

[0146] The spinning process in step S4: the granulation is evenly distributed at 150°C;

[0147] Spinning process in step S4: the material is extruded into filaments through the spinneret by a metering pump, and the spinning speed is 411 m / min;

[0148] The heating and stretching in step S4 is divided into four stages, the temperature of the five groups of hot rollers are all 100° C., and the total stretching ratio is 33.

[0149] S5. The ultra-high molecular weight polyethylene fiber obtained in step S4 is first prepared into a single UD cloth by a wet process, and then a plurality of single UD cloths are made into a laminate, and the obtained laminate is subjected to a ballistic performance test;

[0150] Preparation of single UD cloth in step S5: laying polytetrafluoroethylene cloth and silicone oil on the prepared mold in sequence, winding the ultra-high molecular weight polyethylene fiber obtained in step S4 along the surface of the mold and coating it with polyimide resin, controlling the resin content to 15wt% of the finished single UD cloth mass, and the density of the single UD cloth to 60±5g / m 2 , placed in a room temperature environment to cure for 72 hours, and obtain a single UD cloth finished product;

[0151] Before the ballistic performance test in step S5, the obtained single UD cloth is cut into single pieces of 300 mm x 300 mm with electric scissors, and five single pieces are laid out as a laminate in a 0° / 90° alternating laying manner, and the laminate is placed in a hot pressing mold and sent into a hot pressing machine, and kept warm for 30 minutes under the conditions of a pressure of 1 MPa and a temperature of 128° C., and the laminate is taken out after the pressure is maintained and the temperature is lowered, and the laminate is cured at room temperature and pressure for 168 hours;

[0152] The treated single UD cloth laminate was tested for ballistic limit velocity V50 value and BFS;

[0153] Ballistic limit velocity V50 value test: projecting 5.6g, 7.62mm lead core bullets at a launch distance of 5m, the V50 value is obtained by correcting the results of multiple bullet velocities with similar numbers of penetrations and non-penetrations;

[0154] BFS test: Control the initial velocity of the bullet to 445±10m / s, use a depth gauge with an accuracy of 0.01mm to measure, and take the average value of the bullet hole depth of 6 bullets as the BFS value.

[0155] According to the formula

[0156]

[0157] Where SEA is the absorbed energy of the laminate (J·m 2 / kg), m p is the mass of the lead core bullet (kg), V50 is the limiting velocity of the laminate (m / s), AD is the density of the laminate (kg / m 2 ).

[0158] It is difficult to accurately reflect the performance of an object by measuring a single fiber or fiber segment. The most direct way is to make the fiber into a cloth or further make it into a finished product. This application chooses a compromise method, making the modified ultra-high molecular weight bulletproof polyethylene fiber into a single UD cloth, and then hot-pressing five pieces of cloth into a laminate to simulate the actual bulletproof product. Figure 3 As shown, it is a microscopic schematic diagram of the convexity of the back of the laminate after the actual test, which is also the only parameter that can be intuitively understood. The ballistic limit velocity V50 value and BFS of the sample are tested with reference to the method specified in GJB4300A-2012 "Technical Performance Requirements for Safety of Military Bulletproof Vests", and the data of Examples 1-4 are analyzed and processed to obtain the performance parameters that can generally reflect the modified ultra-high molecular weight polyethylene fiber bulletproof vest in this application, and compared with the existing parameter standards of single ultra-high molecular weight polyethylene fiber (Comparative Example 1) and single polyimide fiber (Comparative Example 2), the situation is shown in Table 1:

[0159]

[0160] Table 1 Comparison of key parameters of ballistic performance

[0161] According to the parameters obtained in Examples 1 to 4, a big data analysis is performed, the interval with the highest frequency of occurrence is taken, the mean values ​​of the four embodiments are compared, all mean value data in this interval are selected, and these mean value data are summed and averaged, and finally more reasonable representative parameter data are obtained. A single ultra-high molecular weight polyethylene fiber and a single polyimide fiber under the same conditions are compared, and it can be found that the modified ultra-high molecular weight bulletproof polyethylene fiber of the present application can withstand faster bullets and absorb more impact force under the same environment, and produce the smallest back bulge, that is, it has better performance in terms of the wearer's protective range, direct impact, deformation damage, etc., and has better ballistic performance.

[0162] It should be noted that this specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A process for preparing modified ultra-high molecular weight polyethylene fiber for bulletproof clothing, characterized in that: The steps include: S1. Preparation of a spinning composite material: A mixture of elastomers A and B and ultra-high molecular weight polyethylene powder are mixed to obtain a spinning composite material; S2. Preparation of a swelling suspension: Adding an emulsifier and an antioxidant to the spinning composite raw material obtained in step S1, stirring and heating in a swelling reactor to obtain a swelling suspension; S3. Preparation of spinning fluid: The swollen suspension is added with a modifying liquid under high temperature and high pressure to complete the blending modification to obtain a spinning fluid; S4. Preparation of ultra-high molecular weight polyethylene fiber for bulletproof vests: The spinning fluid is sequentially subjected to extrusion, spinning, spinning, extraction, drying, heating, stretching and winding to form ultra-high molecular weight polyethylene fiber; S5. The ultra-high molecular weight polyethylene fiber obtained in step S4 is firstly made into a single UD cloth through a wet process, and then a plurality of single UD cloths are made into a laminate, and the obtained laminate is tested for its ballistic performance.

2. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: The component of the elastomer A in step S1 is 4,4' diphenylmethane diisocyanate polyether polyurethane prepolymer; The component of elastomer B is a mixture of amino-terminated polyether and amino-terminated chain extender; The mixing amount of ultra-high molecular weight polyethylene powder is 13-18wt% of the total mass of the elastomer A and B mixed materials.

3. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: In step S2, the emulsifier is selected from one or more of fatty alcohol polyoxyethylene polyoxypropylene ether, dodecyl phosphate monoester, fatty alcohol polyoxyethylene ether, and ethylenediaminetetraacetic acid; The antioxidant is selected from one or more of dioctyl phthalate, triphenyl phosphite, and butylated hydroxytoluene; The swelling temperature is 85-100°C, the stirring speed is 72-115 r / min, and the swelling time is 1-1.5 h.

4. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: In step S3, the high temperature and high pressure environment refers to 195-270°C, 2-50MPa, and the heating rate is 5°C / min; The modified liquid is a polyimide solution after thermal imidization at 195-200°C.

5. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: The extrusion process in step S4 is as follows: first, the spinning fluid is cooled to 85-90° C., and degassed by physical vibration, and then passed through a screw extruder, and extrusion granulation is completed at a speed of 70-120 r / min at a feeding section of 90-110° C., a compression section of 105-145° C., and a metering section of 140-163° C., with a granulation diameter of 4-10 mm; The spinning process in step S4: the granulation is evenly distributed at 150-160°C; The spinning process in step S4: the material is extruded into filaments through a spinneret by a metering pump, and the spinning speed is 320-950 m / min; The heating and stretching in step S4 is divided into four stages, the temperatures of the five groups of hot rollers are all 50-105° C., and the total stretching times are 20-40.

6. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: The wet preparation process in step S5 is as follows: Teflon cloth and silicone oil are laid on the prepared mold in sequence, the ultra-high molecular weight polyethylene fiber obtained in step S4 is wound along the mold surface and coated with polyimide resin, and the resin content is controlled to be 15wt% of the finished single UD cloth mass, and the single UD cloth density is 60±5g / m 2 , and place it at room temperature to cure for 45 to 90 hours to obtain a single UD cloth product.

7. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: Before the ballistic performance test in step S5, the obtained single UD cloth is cut into single pieces of 300 mm x 300 mm with electric scissors, and the single pieces are laid into laminates in a 0° / 90° alternating plying manner, and the laminates are placed in a hot pressing mold and sent into a hot pressing machine. The laminates are kept warm for 30 minutes under the conditions of a pressure of 1 MPa and a temperature of 128°C. After the pressure is maintained and the temperature is lowered, the laminates are taken out and cured at room temperature and pressure for 168 hours.

8. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 7, characterized in that: The treated single UD cloth laminate was tested for ballistic limit velocity V50 value and BFS; Ballistic limit velocity V50 value test: projecting 5.6g, 7.62mm lead core bullets at a launch distance of 5m, the V50 value is obtained by correcting the results of multiple bullet velocities with similar numbers of penetrations and non-penetrations; BFS test: Control the initial velocity of the bullet to 445±10m / s, use a depth gauge with an accuracy of 0.01mm to measure, and take the average value of the bullet hole depth of 6 bullets as the BFS value.

9. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 8, characterized in that: According to the formula Where SEA is the absorbed energy of the laminate (J·m 2 / kg), m p is the mass of the lead core bullet (kg), V50 is the limiting velocity of the laminate (m / s), AD is the density of the laminate (kg / m 2 ).

10. The process for preparing the modified ultra-high molecular weight polyethylene fiber for bulletproof vests according to claim 1, characterized in that: In step S1, the mixing mass ratio of elastomer A to elastomer B is 0.72-0.89:1.

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