High-strength polyurea fiber and preparation method thereof
By optimizing wet spinning parameters and multi-stage stretching process, high-strength polyurea fibers were prepared, which solved the shortcomings of existing bulletproof equipment materials in terms of lightweighting and protection, and achieved the effects of high strength, low density and excellent interfacial bonding.
Patent Information
- Application Number
- CN202511503661.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-21
- Publication Date
- 2026-01-06
AI Technical Summary
Existing bulletproof equipment materials are insufficient in balancing lightweight and high protection. Traditional fiber materials have insufficient interfacial bonding force and low fiber orientation in flexible armor, which limits the overall mechanical properties of composite materials. Furthermore, existing spinning processes are difficult to meet the requirements of high strength and low density.
By optimizing wet spinning parameters, multi-stage stretching, and molecular design, high-strength polyurea fibers are prepared by uniformly mixing unique components A and B under vacuum. Combined with a specific coagulation bath and multi-stage stretching process, the crystallinity and orientation of the fibers are ensured. Residues are removed by hot water washing and hot air drying.
It significantly improves the lightweight and protection level of bulletproof soft armor, with polyurea fiber strength increased by 40%-50% and energy absorption efficiency superior to aramid by 25%-35%, possessing high strength, low density and excellent interfacial bonding performance.
Abstract
Description
Technical Field
[0001] This invention relates to the field of high-strength fiber technology, specifically to a high-strength polyurea fiber and its preparation method. Background Technology
[0002] Modern ballistic armor often uses aramid or ultra-high molecular weight polyethylene fibers to balance lightweight and high protection. While these fibers are lightweight, their high-temperature resistance and shear strength are insufficient, making them vulnerable to repeated impacts from high-speed shrapnel. Furthermore, while ceramic composite armor can effectively absorb kinetic energy, its high brittleness and susceptibility to cracking, coupled with poor secondary protection capabilities, limit its application in flexible armor. Traditional multi-layer composite structures such as ceramic-aramid-polyethylene can improve protection levels, but the interlayer adhesives are prone to aging and failure, and their high areal density affects wearing flexibility. In addition, existing polyurea-based materials are rarely used in flexible armor, highlighting the urgent need to develop fiber materials that combine high strength, low density, and excellent interfacial bonding.
[0003] Polyurea materials have attracted widespread attention due to their high strength, high toughness, and excellent impact resistance. In existing technologies, polyurea is mostly used in coatings or composite matrixes, such as fiber-reinforced polyurea. For example, composites of polyurea and fiber grids can improve blast resistance, but problems such as insufficient interfacial bonding and low fiber orientation limit the overall mechanical properties of the composite material. Furthermore, traditional melt spinning is difficult to apply due to the poor thermal stability of polyurea, while dry spinning is prone to pore defects, further restricting fiber strength. Traditional melt spinning is difficult to apply due to the poor thermal stability of polyurea, while dry spinning is prone to high fiber porosity and insufficient strength due to rapid solvent evaporation. In existing wet spinning processes, improper control of coagulation bath parameters such as temperature gradient and solvent concentration can easily lead to core-sheath structures or internal defects, resulting in low fiber crystallinity and insufficient modulus, making it difficult to meet the energy absorption efficiency requirements of bulletproof armor.
[0004] The potential of polyurea is limited by the shortcomings of its fiberization process, while the requirements of soft armor for lightweight, high elasticity, and resistance to repeated impacts have not yet been fully met. By optimizing wet spinning parameters such as gradient coagulation bath, multi-stage stretching, and molecularly designed high-purity monomer polycondensation, the bottlenecks of traditional fiber strength and modulus can be overcome, providing a new material for ballistic soft armor that combines high strength, low density, and excellent interfacial bonding. Summary of the Invention
[0005] The purpose of this invention is to provide a novel high-strength polyurea fiber and its preparation method. This polyurea fiber has high strength and high modulus, with a strength increase of 40%-50% compared to traditional polyurethane fibers, and an energy absorption efficiency that is 25%-35% better than aramid fibers. It can significantly improve the lightweight and protection level of bulletproof soft armor.
[0006] The high-strength polyurea fiber is prepared by the following steps: A. First, synthesize component A and component B, then stir component A and component B in a weight ratio of 1.2-1.4:1 under vacuum at 70-90°C to obtain polyurea elastomer; component A is synthesized from polyisocyanate and polyether polyol in a weight ratio of 1-2:1, and component B is synthesized from amino-terminated polyether and chain extender in a weight ratio of 0.7-1.2:1. B. Add polyurea elastomer to a polar solution, stir at 50-70℃ for 6-14 hours, and then degas under vacuum to prepare a polyurea spinning solution with a concentration of 10-20 mg / mL. C. The polyurea spinning solution is spun through a spinneret and injected directly into a coagulation bath solution at room temperature. It is allowed to stand to become a solid phase, and then polyurea fibers are obtained through multi-stage stretching. D. Wash and dry the polyurea fiber filaments to obtain high-strength polyurea fibers.
[0007] In step A, the polyisocyanate is one or a mixture of more than one of diphenylmethane diisocyanate, toluene diisocyanate, dimethylbiphenyl diisocyanate, and diphenylmethane diisocyanate. The polyether polyol is PPG 600 or PPG 1000; In step A, the amino-terminated polyether is composed of Jeffamine D-2000 and Jeffamine T-5000, wherein the weight ratio of Jeffamine D-2000 to Jeffamine T-5000 is 5-10:1; In step A, the chain extender is composed of DETDA and EDR-148z, and the weight ratio of DETDA to EDR-148z is 0.5-1.8:1.
[0008] The preparation method of component A includes the following steps: Add polyether polyol to a closed reactor and dehydrate under reduced pressure at 95-120°C until the water content of the polyether polyol is ≤0.05%. Then cool down to 50-60°C, add isocyanate, and then heat up to 70-80°C under stirring. React for 2-3 hours. After the reaction is complete, cool down to below 60°C and discharge the product. The preparation method of component B includes the following steps: Chain extender, amino-terminated polyether, and catalyst are added sequentially to a sealed reactor and stirred evenly for 1-2 hours. The mixture is then dehydrated under reduced pressure at 90-100°C for 1.5-2 hours and filtered to obtain the final product. The catalyst is an amine catalyst, preferably triethylenediamine.
[0009] The molecular weight of the polyurea elastomer is ≥100,000.
[0010] In step B, the polar solution is N,N-dimethylacetamide at a mass percentage of 15-20%.
[0011] In step B, the vacuum degassing treatment takes 3-5 hours, and after the vacuum degassing treatment is completed, ultrasonic treatment is performed for 2-5 minutes. Preferably, the vacuum adopts a stepped vacuum degree, and the process is as follows: first, a vacuum degree of -0.9-0.95MPa is used to maintain the vacuum for 1-2.5 hours; then, a vacuum degree of -0.95-0.1MPa is used to maintain the vacuum for the remaining time.
[0012] In step C, the diameter of the spinneret orifice is 80-100 μm, and the spinneret speed is 30-70 m / min.
[0013] Preferably, in step C, the coagulation bath is a solution in which deionized water, acetone, and a polar solution are mixed evenly in a weight ratio of 70-90 : 7-11 : 8-13. Preferably, the polar solution is N,N-dimethylformamide or N,N-dimethylacetamide.
[0014] In step C, the multi-stage stretching includes the following steps: The material is first pre-stretched 2-3 times in a coagulation bath at 30-40℃, and then stretched 5-10 times in hot air at 60-180℃.
[0015] In step D, the washing process uses hot water at 60-80℃, and the drying process is carried out in hot air at 60-80℃.
[0016] The present invention also provides a method for preparing high-strength polyurea fibers, comprising the following steps: A. First, synthesize component A and component B, then stir component A and component B in a weight ratio of 1.2-1.4:1 under vacuum at 70-90°C to obtain polyurea elastomer; component A is synthesized from polyisocyanate and polyether polyol in a weight ratio of 1-2:1, and component B is synthesized from amino-terminated polyether and chain extender in a weight ratio of 0.7-1.2:1. B. Add the polyurea elastomer to the polar solution and stir evenly at 50-70℃ to prepare a polyurea spinning solution with a concentration of 10-20 mg / mL. C. The polyurea spinning solution is spun through a spinneret and injected directly into the coagulation bath solution. It is allowed to stand to become a solid phase, and then polyurea fibers are obtained through multi-stage stretching. D. Wash and dry the polyurea fiber filaments to obtain high-strength polyurea fibers.
[0017] The beneficial effects of this invention are as follows: Based on the unique composition of components A and B, this invention can obtain a polyurea fiber with higher strength and higher modulus through the polycondensation reaction of diisocyanate and terminal amino polyether. The strength is increased by 40%-50% compared with traditional polyurethane fiber, and the energy absorption efficiency is 25%-35% better than aramid, which significantly improves the lightweight and protection level of bulletproof soft armor.
[0018] This invention also innovates the preparation method, especially the unique coagulation bath composition and multi-stage stretching process. The coagulation bath meets the crystallinity, orientation, and mechanical property requirements of high-strength polyurea fibers. Combined with the multi-stage stretching process, it significantly improves the crystallinity and orientation of the nascent fibers. Furthermore, by using appropriate spinneret orifice diameters and spinneret speeds, it ensures better nascent fiber forming quality and mechanical properties.
[0019] The present invention also ensures the removal of solvents and coagulation bath components from the fiber surface through hot water washing and hot air drying, thus avoiding residues that weaken the mechanical properties of high-strength polyurea fibers.
[0020] This invention combines the advantages of high strength, low cost, and green manufacturing, providing a revolutionary material solution for the protection field and showing promising application prospects. Detailed Implementation
[0021] Example 1
[0022] The high-strength polyurea fiber of this embodiment is prepared by the following steps: A. First, synthesize component A and component B, then stir component A and component B in a weight ratio of 1.2:1 at 70°C under vacuum to obtain polyurea elasticity; component A is synthesized from polyisocyanate and polyether polyol in a weight ratio of 1:1, and component B is synthesized from amino-terminated polyether and chain extender in a weight ratio of 0.7:1. The polyisocyanate is one or a mixture of more than one of diphenylmethane diisocyanate, toluene diisocyanate, dimethylbiphenyl diisocyanate, and diphenylmethane diisocyanate; The polyether polyol is PPG600; The amino-terminated polyether is composed of Jeffamine D-2000 and Jeffamine T-5000, wherein the weight ratio of Jeffamine D-2000 to Jeffamine T-5000 is 5:1; The chain extender consists of DETDA and EDR-148z in a weight ratio of 0.5:1.
[0023] The preparation method of component A includes the following steps: Polyether polyol is added to a closed reactor and dehydrated under reduced pressure at 95°C until the water content of the polyether polyol is ≤0.05%. Then the temperature is lowered to 50°C, isocyanate is added, and then the temperature is raised to 70°C under stirring and the reaction is carried out for 2 hours. After the reaction is completed, the temperature is lowered to below 60°C and the product is discharged. The preparation method of component B includes the following steps: Chain extender, amino-terminated polyether, and triethylenediamine were added sequentially to a sealed reactor and stirred evenly for 1 hour. The mixture was then dehydrated under reduced pressure at 90°C for 1.5 hours and filtered to obtain the final product. B. Add polyurea elastomer to a 15% N,N-dimethylacetamide solution and stir at 50°C for 6 hours while stirring under vacuum to prepare a 10 mg / mL polyurea spinning solution. The vacuum degassing treatment lasted for 3 hours. After the vacuum degassing treatment was completed, ultrasonic treatment was performed for 2 minutes to prepare the polyurea spinning solution. The vacuum degassing process employs a stepped vacuum degree, as follows: First, a vacuum degree of -0.9-0.95 MPa is maintained for 1 hour to remove large bubbles from the solution; then, a vacuum degree of -0.95-0.1 MPa is maintained for 2 hours to remove micro-bubbles.
[0024] C. The polyurea spinning solution is spun through a spinneret and injected directly into a coagulation bath solution at room temperature. It is allowed to stand to become a solid phase, and then polyurea fibers are obtained through multi-stage stretching. The spinneret diameter is 80μm, and the spinneret speed is 30m / min; The coagulation bath is a solution in which deionized water, acetone, and a polar solution are mixed evenly in a weight ratio of 70:7:8. The polar solution is N,N-dimethylformamide.
[0025] The multi-stage stretching includes the following steps: The material is first pre-stretched twice in a coagulation bath at 30°C, and then stretched five times in hot air at 60°C.
[0026] D. Wash the polyurea fiber filaments with hot water at 60°C and dry them in hot air at 60°C to obtain high-strength polyurea fiber. Example 2
[0027] The high-strength polyurea fiber of this embodiment is prepared by the following steps: A. First, synthesize component A and component B, then stir component A and component B in a weight ratio of 1.4:1 at 90°C under vacuum to obtain polyurea elasticity; component A is synthesized from polyisocyanate and polyether polyol in a weight ratio of 2:1, and component B is synthesized from amino-terminated polyether and chain extender in a weight ratio of 0.7-1.2:1. The polyisocyanate is one or a mixture of more than one of diphenylmethane diisocyanate, toluene diisocyanate, dimethylbiphenyl diisocyanate, and diphenylmethane diisocyanate; The polyether polyol is PPG 600 or PPG 1000; The amino-terminated polyether is composed of Jeffamine D-2000 and Jeffamine T-5000, wherein the weight ratio of Jeffamine D-2000 to Jeffamine T-5000 is 10:1; The chain extender consists of DETDA and EDR-148z in a weight ratio of 1.8:1.
[0028] The preparation method of component A includes the following steps: Polyether polyol is added to a closed reactor and dehydrated under reduced pressure at 120°C until the water content of the polyether polyol is ≤0.05%. Then the temperature is lowered to 60°C, isocyanate is added, and the temperature is raised to 80°C under stirring. The reaction is carried out for 3 hours. After the reaction is completed, the temperature is lowered to below 60°C and the product is discharged. The preparation method of component B includes the following steps: Chain extender, amino-terminated polyether, and triethylenediamine were added sequentially to a sealed reactor and stirred evenly for 2 hours. The mixture was then dehydrated under reduced pressure at 100°C for 2 hours and filtered to obtain the final product. B. Add polyurea elastomer to a 20% N,N-dimethylacetamide solution and stir at 70°C for 14 hours while stirring, with the vacuum turned on, to prepare a polyurea spinning solution with a concentration of 20 mg / mL. The vacuum degassing treatment lasted for 5 hours, followed by 5 minutes of ultrasonic treatment; a polyurea spinning solution was then prepared. The vacuum is applied in a stepped vacuum manner, and the process is as follows: First, a vacuum of -0.9-0.95 MPa is maintained for 2.5 hours to remove large bubbles from the solution; then, a vacuum of -0.95-0.1 MPa is maintained for 2.5 hours to remove small bubbles.
[0029] C. The polyurea spinning solution is spun through a spinneret and injected directly into a coagulation bath solution at room temperature. It is allowed to stand to become a solid phase, and then polyurea fibers are obtained through multi-stage stretching. The spinneret diameter is 100μm, and the spinneret speed is 70m / min; The coagulation bath is a solution in which deionized water, acetone, and a polar solution are mixed evenly in a weight ratio of 90:11:13. The polar solution is N,N-dimethylacetamide.
[0030] The multi-stage stretching includes the following steps: The material is first pre-stretched three times in a coagulation bath at 40°C, and then stretched ten times in hot air at 180°C.
[0031] D. Wash the polyurea fiber filaments with hot water at 80°C and dry them in hot air at 80°C to obtain high-strength polyurea fibers. Example 3
[0032] The high-strength polyurea fiber of this embodiment is prepared by the following steps: A. First, synthesize component A and component B, then stir component A and component B in a weight ratio of 1.3:1 at 80°C under vacuum to obtain polyurea elasticity; component A is synthesized from polyisocyanate and polyether polyol in a weight ratio of 1.5:1, and component B is synthesized from amino-terminated polyether and chain extender in a weight ratio of 1:1. The polyisocyanate is one or a mixture of more than one of diphenylmethane diisocyanate, toluene diisocyanate, dimethylbiphenyl diisocyanate, and diphenylmethane diisocyanate; The polyether polyol is PPG 600 or PPG 1000; The amino-terminated polyether is composed of Jeffamine D-2000 and Jeffamine T-5000, wherein the weight ratio of Jeffamine D-2000 to Jeffamine T-5000 is 7:1; The chain extender consists of DETDA and EDR-148z in a weight ratio of 1:1.
[0033] The preparation method of component A includes the following steps: Polyether polyol is added to a closed reactor and dehydrated under reduced pressure at 110°C until the water content of the polyether polyol is ≤0.05%. Then the temperature is lowered to 55°C, isocyanate is added, and then the temperature is raised to 75°C under stirring and the reaction is carried out for 2.5 hours. After the reaction is completed, the temperature is lowered to below 60°C and the product is discharged. The preparation method of component B includes the following steps: Chain extender, amino-terminated polyether, and triethylenediamine were added sequentially to a sealed reactor and stirred evenly for 1.5 hours. The mixture was then dehydrated under reduced pressure at 95°C for 1.8 hours and filtered to obtain the final product. B. Add polyurea elastomer to an 18% N,N-dimethylacetamide solution and stir at 60°C for 9 hours while stirring, with the vacuum turned on, to prepare a polyurea spinning solution with a concentration of 15 mg / mL. In step B, the vacuum degassing treatment takes 4 hours, and after the vacuum degassing treatment is completed, ultrasonic treatment is performed for 3 minutes. The vacuum is applied in a stepped vacuum manner, and the process is as follows: First, a vacuum of -0.9-0.95 MPa is maintained for 1.5 hours to remove large bubbles from the solution; then, a vacuum of -0.95-0.1 MPa is maintained for 2.5 hours to remove small bubbles.
[0034] C. The polyurea spinning solution is spun through a spinneret and injected directly into a coagulation bath solution at room temperature. It is allowed to stand to become a solid phase, and then polyurea fibers are obtained through multi-stage stretching. The spinneret orifice diameter is 90μm, and the spinneret speed is 50m / min; The coagulation bath is a solution in which deionized water, acetone, and a polar solution are mixed evenly in a weight ratio of 80:9:10. The polar solution is N,N-dimethylformyl.
[0035] The multi-stage stretching includes the following steps: The material is first pre-stretched 2.5 times in a coagulation bath at 35°C, and then stretched 8 times in hot air at 120°C.
[0036] D. Wash the polyurea fiber filaments with hot water at 70°C and dry them in hot air at 70°C to obtain high-strength polyurea fiber. Example 4
[0037] The high-strength polyurea fiber of this embodiment is prepared by the following steps: A. Preparation of high-strength, high-modulus polyurea elastomers Polyether polyol was added to a reactor and dehydrated under reduced pressure at 95°C for 2 hours. The temperature was then lowered to 55°C, and isocyanate was added. The temperature was raised to 80°C while ensuring the polyether polyol and isocyanate were stirred evenly. The reaction was maintained for 1.5 hours. After the reaction was complete, the temperature was lowered to 55°C and the product was discharged to obtain isocyanate semi-prepolymer component A, ensuring the -NCO content of component A was 10%. The weight ratio of isocyanate to polyether polyol was 1.2:1. A high molecular weight terminal amino polyether was obtained by combining Jeffamine D-2000 and T-5000 at a weight ratio of 6:1. A chain extender was obtained by combining DETDA and EDR-148 at a weight ratio of 0.8:1. The terminal amino polyether and the chain extender were added to the reactor at a weight ratio of 0.9:1, along with triethylenediamine, and the mixture was dehydrated at high temperature while ensuring uniform mixing to obtain the terminal amino polyether component B.
[0038] Component A and component B are mixed to obtain a high-strength, high-modulus polyurea elastomer.
[0039] B. Preparation of spinning solution B. Add the polyurea elastomer to a 15% N,N-dimethylacetamide solution and stir magnetically at 60°C for 9 hours while simultaneously applying a vacuum. After stirring, perform ultrasonic treatment for 5 minutes to prepare a polyurea spinning solution with a concentration of 13 mg / mL. The solution was subjected to vacuum degassing using a stepped vacuum method. First, a vacuum of -0.9 to 0.95 MPa was maintained for 1.5 hours to remove large bubbles from the solution. Then, a vacuum of -0.95 to 0.1 MPa was maintained for 2 hours to remove micro-bubbles. At the same time, high-frequency vibration using 40 kHz ultrasound was applied to accelerate the detachment of bubbles from the liquid phase, resulting in a polyurea spinning solution.
[0040] C. Spinning and Coagulation Bath Preparation By using a spinneret orifice diameter of 80μm and a spinneret speed of 30m / min, continuous nascent fibers with a diameter of approximately 80μm were obtained.
[0041] The coagulation bath is a mixed solution obtained from deionized water, acetone, and a polar solution in a weight ratio of 80:11:8, designed to meet the requirements for crystallinity, orientation, and mechanical properties of high-strength polyurea fibers. The polar solution is N,N-dimethylacetamide.
[0042] D. Multi-stage tension First, the nascent fibers are pre-stretched twice in a coagulation bath at room temperature. Then, the nascent fibers are dried and subjected to a multi-stage stretching treatment at 100°C, thereby improving the crystallinity and orientation of the polyurea fibers.
[0043] E. Post-processing The obtained polyurea fiber filaments were washed with hot water at 70°C and dried with hot air at 70°C to remove residual solvent and prevent fiber weakening, ultimately yielding high-strength polyurea fibers.
[0044] Example 5 A. Preparation of high-strength, high-modulus polyurea elastomers Polyether polyol was added to a reactor and dehydrated under reduced pressure at 95°C for 2 hours. The temperature was then lowered to 55°C, and isocyanate was added. The temperature was raised to 80°C while ensuring the amino polyether and isocyanate were stirred evenly. The reaction was maintained for 1.5 hours. After the reaction was complete, the temperature was lowered to 55°C and the product was discharged to obtain isocyanate semi-prepolymer component A, ensuring the -NCO content of component A was 12%. The weight ratio of isocyanate to polyether polyol was 1.3:1. A high molecular weight terminal amino-terminated polyether obtained by combining Jeffamine D-2000 and T-5000 at a weight ratio of 8:1, a chain extender obtained by combining DETDA and EDR-148 at a weight ratio of 1.3:1, and triethylenediamine were added to a reactor for high-temperature dehydration while ensuring uniform mixing, to obtain component B of the terminal amino-terminated polyether. Component A and component B were then mixed at a weight ratio of 1.3:1 to obtain a high-strength, high-modulus polyurea elastomer.
[0045] B. Preparation of spinning solution Polyurea elastomer was added to a highly polar solvent, N,N-dimethylacetamide, at 18% by mass, and magnetically stirred at 60°C for 8 hours to ensure uniform mixing. Then, vacuum degassing was performed for 4 hours, followed by 4 minutes of ultrasonic treatment; a polyurea spinning solution with a concentration of 15 mg / mL was prepared. The vacuum degassing process employs a stepped vacuum method. First, a vacuum of -0.9 to 0.95 MPa is maintained for 1.5 hours to remove large bubbles from the solution. Then, a vacuum of -0.95 to 0.1 MPa is maintained for 2.5 hours to remove micro-bubbles. Finally, high-frequency vibration at 40 kHz is applied for 4 minutes to accelerate the detachment of bubbles from the liquid phase, resulting in a polyurea spinning solution.
[0046] C. Spinning and Coagulation Bath Preparation By using a spinneret orifice diameter of 90μm and a spinneret speed of 50m / min, continuous nascent fibers with a diameter of approximately 90μm were obtained.
[0047] The coagulation bath is a mixed solution obtained from deionized water, acetone, and a polar solution in a weight ratio of 80:11:8, designed to meet the requirements for crystallinity, orientation, and mechanical properties of high-strength polyurea fibers. The polar solution is N,N-dimethylformamide.
[0048] D. Multi-stage tension First, the nascent fibers are pre-stretched twice in a coagulation bath at room temperature. Then, the nascent fibers are dried and subjected to a multi-stage stretching treatment at 100°C, thereby improving the crystallinity and orientation of the polyurea fibers.
[0049] E. Post-processing The obtained polyurea fiber filaments were washed with hot water at 70°C and dried with hot air at 70°C to remove residual solvent and prevent fiber weakening, ultimately yielding high-strength polyurea fibers.
[0050] Example 6 A. Preparation of high-strength, high-modulus polyurea elastomers Polyether polyol was added to a reactor and dehydrated under reduced pressure at 100°C for 2 hours. The temperature was then lowered to 55°C, and isocyanate was added. The temperature was raised to 80°C while ensuring the amino polyether and isocyanate were stirred evenly. The reaction was maintained for 1.5 hours. After the reaction was complete, the temperature was lowered to 55°C and the product was discharged to obtain isocyanate semi-prepolymer component A, ensuring that the -NCO content of component A was 15%.
[0051] The weight ratio of isocyanate to polyether polyol is 1.4:1. A high molecular weight terminal amino-terminated polyether obtained by combining Jeffamine D-2000 and T-5000 at a weight ratio of 7:1, a chain extender obtained by combining DETDA and EDR-148 at a weight ratio of 1.6:1, and triethylenediamine were added to a reactor for high-temperature dehydration while ensuring uniform mixing, to obtain component B of the terminal amino-terminated polyether. Component A and component B were then mixed at a weight ratio of 1.4:1 to obtain a high-strength, high-modulus polyurea elastomer.
[0052] B. Preparation of spinning solution Polyurea elastomer was added to a highly polar solvent, N,N-dimethylacetamide, at 20% by mass. The solution was magnetically stirred at 60°C for 10 hours to ensure uniform mixing. Then, vacuum degassing was performed for 5 hours, followed by 5 minutes of ultrasonic treatment. This yielded a polyurea spinning solution with a concentration of 20 mg / mL. The solution was subjected to vacuum degassing using a stepped vacuum method. First, a vacuum of -0.9 to 0.95 MPa was maintained for 3 hours to remove large bubbles from the solution. Then, a vacuum of -0.95 to 0.1 MPa was maintained for 2 hours to remove micro bubbles. At the same time, 40 kHz ultrasound was used for high-frequency vibration to accelerate the detachment of bubbles from the liquid phase, resulting in a polyurea spinning solution.
[0053] C. Spinning and Coagulation Bath Preparation By using a spinneret orifice diameter of 100μm and a spinneret speed of 70m / min, continuous nascent fibers with a diameter of approximately 100μm were obtained.
[0054] The coagulation bath is a mixed solution obtained from deionized water, acetone, and a polar solution in a weight ratio of 80:11:8, designed to meet the requirements for crystallinity, orientation, and mechanical properties of high-strength polyurea fibers. The polar solution is N,N-dimethylformamide.
[0055] D. Multi-stage tension First, the nascent fibers are pre-stretched twice in a coagulation bath at room temperature. Then, the nascent fibers are dried and subjected to a multi-stage stretching treatment at 100°C, thereby improving the crystallinity and orientation of the polyurea fibers.
[0056] E. Post-processing The obtained polyurea fiber filaments were washed with hot water at 70°C and dried with hot air at 70°C to remove residual solvent and prevent fiber weakening, ultimately yielding high-strength polyurea fibers.
[0057] The main performance indicators of the high-strength polyurea fiber used in the ballistic soft armor of Examples 4-6 above are shown in the table below: project Indicator Requirements Example 4 Example 5 Example 6 Tensile strength / MPa ≥20 32.7 36.7 34.6 Elongation at break / % ≥300 425 470 480 Elastic modulus / GPa ≥1.5 1.9 2.0 2.0 .
[0058] The performance parameters in the table indicate that the high-strength polyurea fiber synthesized in this invention has excellent tensile strength and elongation at break, as well as a high elastic modulus, achieving the expected results of this invention.
[0059] The embodiments described above in this patent are merely illustrative of the implementation methods of this invention and are not limited to the embodiments described above. For those skilled in the art, simple substitutions, modifications, and variations implemented within the technical concept and principle framework of this invention should all satisfy the protection scope of the claims described in this invention.
Claims
1. A high-strength polyurea fiber, characterized by, The preparation method comprises the following steps: A, first synthesize component A and component B, then use component A and component B with weight ratio of 1.2-1.4:1 to stir uniformly under vacuum at 70-90°C, to prepare polyurea elastomer; the component A is synthesized by polyisocyanate and polyether polyol with weight ratio of 1-2:1, the component B is synthesized by terminal amino polyether and chain extender with weight ratio of 0.7-1.2:1; B, add polyurea elastomer into polar solution, stir at 50-70°C for 6-14h, then treat by vacuum degassing, to prepare 10-20mg / mL polyurea spinning solution; C, spin the polyurea spinning solution through spinneret, directly inject into coagulation bath solution, stand to become solid phase, then through multi-stage stretching, to obtain polyurea fiber; D, wash the polyurea fiber, dry, to obtain high-strength polyurea fiber. 2.The high-strength polyurea fiber according to claim 1, characterized in that: In step A, the polyisocyanate is one or more than one of diphenylmethane diisocyanate, toluene diisocyanate, dimethyl diphenyl diisocyanate, diphenylmethane diisocyanate; The polyether polyol is PPG600 or PPG1000; In step A, the terminal amino polyether is composed of Jeffamine D-2000 and Jeffamine T-5000, wherein the weight ratio of Jeffamine D-2000 to Jeffamine T-5000 is 5-10:1; In step A, the chain extender is composed of DETDA and EDR-148z, and the weight ratio of DETDA to EDR-148z is 0.5-1.8:
1. 3.The high-strength polyurea fiber according to claim 1, characterized in that: The preparation method of component A comprises the following steps: Add the polyether polyol into a sealed reaction kettle, dehydrate under reduced pressure at a temperature of 85-120°C until the water content of the polyether polyol is ≤0.05%, then cool to 50-60°C, add isocyanate, then under stirring, warm to 70-80°C, react for 2-3h, after the reaction is completed, cool to below 60°C, and discharge, to obtain the component A; The preparation method of component B comprises the following steps: Add the chain extender, the terminal amino polyether and the catalyst into a sealed reaction kettle in sequence, stir uniformly for 1-2h, dehydrate under reduced pressure at a temperature of 90-100°C for 1.5-2h, and filter, to obtain the component B; The catalyst is an amine catalyst, and preferably, triethylenediamine.
4. The high-strength polyurea fiber according to claim 1, wherein: The molecular weight of the polyurea elastomer is ≥100000.
5. The high-strength polyurea fiber according to claim 1, wherein: In step B, the polar solution is N,N-dimethylacetamide with mass percentage of 15-20%. 6.The high-strength polyurea fiber according to claim 1, characterized in that: In step B, the vacuum degassing treatment time is 3-5h, and after the vacuum degassing treatment is completed, ultrasonic treatment is performed for 2-5min. Preferably, the vacuum adopts a stepwise vacuum degree, and the process is as follows: first, a vacuum degree of-0.9-0.95 MPa is adopted to keep for 1-2.5 h; then, a vacuum degree of-0.95-0.1 MPa is adopted to keep for the remaining time. 7.The high-strength polyurea fiber according to claim 1, wherein: In step C, the diameter of the spinning hole is 80-100 μm, and the spinning speed is 30-70 m / min. Preferably, in step C, the coagulation bath is a solution uniformly mixed by deionized water, acetone and a polar solution in a weight ratio of 70-90 : 7-11 : 8-13. Preferably, the polar solution is N, N-dimethylformamide or N, N-dimethylacetamide.
8. The high-strength polyurea fiber according to claim 1, wherein: In step C, the multi-stage stretching includes the following steps: First, pre-stretching by 2-3 times in a coagulation bath at 30-40 ℃, and then stretching by 5-10 times in hot air at 60-180 ℃. 9.The high-strength polyurea fiber according to claim 1, wherein: In step D, the washing is performed by hot water at 60-80 ℃, and the drying is performed by hot air at 60-80 ℃.
10. A process for the production of high-strength polyurea fibers, characterized by, The method includes the following steps: A, first, component A and component B are synthesized, and then component A and component B in a weight ratio of 1.2-1.4: 1 are stirred uniformly under vacuum at 70-90 ℃ to prepare a polyurea elastomer; component A is synthesized by polyisocyanate and polyether polyol in a weight ratio of 1-2: 1, and component B is synthesized by amino-terminated polyether and a chain extender in a weight ratio of 0.7-1.2: 1; B, the polyurea elastomer is added to a polar solution, and stirred uniformly at 50-70 ℃ to prepare a polyurea spinning solution of 10-20 mg / mL; C, the polyurea spinning solution is spun through a spinning hole, and the spinning is directly injected into a coagulation bath solution, and then left to become a solid phase, and then stretched by multiple stages to obtain a polyurea fiber; D, the polyurea fiber is washed and dried to obtain a high-strength polyurea fiber.