A modified ultra-high molecular weight polyethylene stab-resistant fiber and preparation method thereof

Abstract

The present invention belongs to the technical field of fabrics, and specifically relates to a modified ultra-high molecular weight polyethylene stab-resistant fiber and a preparation method thereof. The preparation method comprises: 1) adding mesoporous WO3 and surface hydroxylated BN to ethanol for ultrasonic dispersion, adding water and stirring to obtain WO3‑BN; 2) mixing WO3‑BN with a PTFE suspension, and then adding a silane coupling agent and stirring to obtain a modified nanocomposite material; 3) putting ultra-high molecular weight polyethylene, the modified nanocomposite material, and an antioxidant into a twin-screw extruder for melting and mixing, conveying, and shearing, extruding through melt spinning, cooling in a water bath, and obtaining a primary fiber through three-stage heat stretching and winding to obtain a modified ultra-high molecular weight polyethylene stab-resistant fiber. The modified ultra-high molecular weight polyethylene stab-resistant fiber prepared by the present invention has excellent tensile strength, tensile modulus, cut resistance, and puncture resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of fabrics, and particularly relates to a modified ultra-high molecular weight polyethylene stab-proof fiber and a preparation method thereof. Background Art

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber is known as the world's three major high-performance special fibers along with carbon fiber and aramid fiber. It is currently the lightest high-performance fiber in the world and also the fiber with the highest specific strength and specific modulus. Ultra-high molecular weight polyethylene fiber has been widely used in bulletproof, explosion-proof, rope, stab-proof, cut-proof and other fields due to its outstanding high strength, high modulus, impact resistance, low temperature resistance and self-lubrication.

[0003] In order to improve the performance of UHMWPE, the prior art discloses many methods for modifying UHMWPE. CN106988122B discloses that ultra-high molecular weight polyethylene jelly silk is impregnated, ozonized and heat-stretched in a vinyl block copolymer solution containing double bonds, so that the surface properties of UHMWPE are improved, the reactive group sites are increased, and it has good mechanical properties and wettability. CN117626638A discloses that a layer of carbon nanotubes is coated on the outer layer of UHMWPE fiber, so that the carbon nanotubes and UHMWPE are connected in the form of amide bonds, the excellent mechanical properties of carbon nanotubes are effectively exerted, and the various mechanical indicators of the composite fiber are improved. Although the existing modification methods improve certain properties of UHMWPE fibers, there are still deficiencies in wear resistance and puncture resistance. The puncture resistance of pure fabrics with a single structure is poor, and it is necessary to further improve its strength and modulus while ensuring toughness. Therefore, it is necessary to explore new modification methods to improve the puncture resistance of UHMWPE fibers.

[0004] Some studies have shown that adding nanoparticles to polymer materials can enhance their electrical, mechanical, antibacterial and friction properties, such as adding graphene oxide, molybdenum sulfide, boron nitride, tungsten dioxide, carbon nanotubes, MXene, hydroxyapatite, etc., which have been proven to be effective in many applications. Chagas mentioned in Ballistic performance of boron carbidenanoparticles reinforced ultra-high molecular weight polyethylene (UHMWPE): adding boron carbide nanoparticles to ultra-high molecular weight polyethylene polymers through twin-screw extrusion and compression molding processes can significantly improve their hardness, melting point, wear resistance and crack resistance. CN107557895A discloses a modified ultra-high molecular weight polyethylene fiber blending preparation method, which blends ultra-high molecular weight polyethylene fibers with PTFE fibers, and the resulting blended fibers have the characteristics of high temperature resistance, corrosion resistance, and excellent mechanical properties. Tungsten trioxide (WO3) is a multifunctional material with many uses, such as preparing tungsten products, as a catalyst, target material, ceramic raw material, dimming glass material, shielding material, fuel cell carrier and preparing resistor elements, etc. The existing technology rarely uses WO3 in modifying ultra-high molecular weight polyethylene fibers.

[0005] Based on the above background technology, the present invention proposes a modified ultra-high molecular weight polyethylene stab-resistant fiber and a preparation method thereof. Summary of the invention

[0006] The first object of the present invention is to provide a method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber, comprising the following steps:

[0007] (1) adding mesoporous WO3 and surface hydroxylated BN into ethanol for ultrasonic dispersion, adding water for heating and stirring, cooling to room temperature, filtering, washing and drying to obtain WO3-BN;

[0008] (2) Mixing WO3-BN and PTFE suspension, adding silane coupling agent and stirring, filtering and drying to obtain a modified nanocomposite material;

[0009] (3) Ultra-high molecular weight polyethylene, modified nano-composite materials, antioxidant 1010 and antioxidant 168 are put into a twin-screw extruder for melting, mixing, conveying and shearing, and then extruded by melt spinning and cooled in a water bath to obtain spun fibers; after three-stage heat stretching and winding of the spun fibers, the modified ultra-high molecular weight polyethylene stab-resistant fibers are obtained.

[0010] Preferably, in step (1), the mass ratio of the mesoporous WO3 to the surface hydroxylated BN is 1:0.5-0.8; the volume ratio of the ethanol to water is 2-2.5:1. The mesoporous structure of WO3 increases its specific surface area and active sites, which is conducive to the combination with hydroxylated boron nitride.

[0011] Preferably, the ultrasonic dispersion in step (1) lasts for 2-2.5 h, and the heating and stirring is carried out at a temperature of 180-190°C for 2-3 h. Through ultrasonic dispersion and heating and stirring, WO3 and surface hydroxylated BN can be uniformly mixed to form a stable composite structure.

[0012] Preferably, the preparation method of the surface hydroxylated BN in step (1) is: adding BN to a sodium hydroxide solution, stirring at 110-120°C for 10-20 h, filtering, washing and drying to obtain the product. The surface hydroxylation of BN can not only improve its binding ability with mesoporous WO3, but also the surface hydroxyl groups can form hydrogen bonds with the amino groups in the silane coupling agent, which is beneficial to the subsequent surface modification of WO3-BN.

[0013] Preferably, the preparation method of mesoporous tungsten trioxide in step (1) is: taking KIT-6 as a silicon-based template and dispersing it in ethanol, adding phosphotungstic acid and stirring, evaporating the solvent and then calcining the solid, and then removing the silicon substrate from the calcined product with HF to obtain mesoporous WO3.

[0014] More preferably, in step (1), the mass ratio of KIT-6 to phosphotungstic acid is 1:2-3, the stirring time is 1-2 h, the calcination temperature is 500-550° C., and the calcination time is 5-5.5 h.

[0015] Preferably, in step (2), the mass ratio of WO3-BN, PTFE and silane coupling agent is 4-5:1:1-2; the stirring time is 2-3 h; and the silane coupling agent is 3-aminopropyltriethoxysilane.

[0016] Preferably, in step (3), the mass ratio of ultra-high molecular weight polyethylene, modified nanocomposite material, antioxidant 1010, and antioxidant 168 is (90-100):(3-5):(0.1-0.5):(0.1-0.5).

[0017] Preferably, the three-stage heat stretching in step (3) is as follows: the temperature of the first-stage stretching is 70-90°C, and the multiple is 3-6 times; the temperature of the second-stage stretching is 100-120°C, and the multiple is 2-5 times; the temperature of the third-stage stretching is 130-135°C, and the multiple is 1.5-3 times.

[0018] Preferably, the temperature of the melt spinning extrusion in step (3) is 280-310°C, and the temperature of the water bath cooling is 30-40°C.

[0019] The second object of the present invention is to provide a modified ultra-high molecular weight polyethylene stab-resistant fiber obtained according to the above preparation method.

[0020] Compared with the prior art, the beneficial effects of the present invention are mainly:

[0021] 1. The present invention first combines surface hydroxylated boron nitride on mesoporous WO3 to form a stable WO3-BN, then mixes it with PTFE and uses a silane coupling agent to perform surface modification to obtain a modified nanocomposite material, and uses the modified nanocomposite material as an inorganic filler to blend and spin with ultra-high molecular weight polyethylene to prepare modified ultra-high molecular weight polyethylene fibers. The modified ultra-high molecular weight polyethylene stab-resistant fiber prepared by the present invention has excellent cutting resistance, puncture resistance and wear resistance.

[0022] 2. The present invention utilizes the excellent mechanical properties and hardness of boron nitride, hydroxylates its surface and combines it with mesoporous WO3 to form a WO3-BN composite material. The synergistic effect between BN and WO3 in the composite material can significantly improve the material's resistance to cutting and puncture. Then, a silane coupling agent is used to enhance the compatibility between WO3-BN, PTFE and ultra-high molecular weight polyethylene to ensure the bonding force between the filler and the polymer matrix. At the same time, the lubricating properties of PTFE itself can also reduce the wear of the fiber during friction, thereby improving the overall wear resistance of the fiber. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further explained below in conjunction with specific embodiments, comparative examples and test examples.

[0024] In the following examples, comparative examples and test examples, the raw materials and preparation methods used are conventional materials and techniques in the art unless otherwise specified.

[0025] The preparation method of mesoporous tungsten trioxide in the following embodiment is as follows: KIT-6 is taken as a silicon-based template and dissolved in ethanol, stirred for 30 min, phosphotungstic acid is added to the solution at a mass ratio of KIT-6: phosphotungstic acid = 1:2-3, and stirring is continued for 1-2 hours, and then the solvent is evaporated to dryness, and the obtained solid is calcined at 500-550 ° C for 5-5.5 h; HF is added to the calcined product to remove the silicon substrate, filtered, washed with a mixture of deionized water and ethanol for 2-3 times, and dried at 110-120 ° C for 1-1.5 h to obtain mesoporous WO3.

[0026] Example 1

[0027] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber comprises the following steps:

[0028] (1) Boron nitride was dissolved in 1 mol / L sodium hydroxide solution, stirred at 110 °C for 10 h, filtered, rinsed with deionized water, and dried to obtain surface hydroxylated BN; mesoporous WO3 and surface hydroxylated BN were added to ethanol at a mass ratio of WO3:BN=1:0.5, ultrasonically dispersed for 2 h, transferred the mixed solution to a hydrothermal reactor, added with deionized water (the volume ratio of deionized water to the above ethanol was 1:2), and stirred at 180 °C for 2 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain WO3-BN.

[0029] (2) PTFE nanoparticles were dispersed in deionized water and dispersed by ultrasonic for 30 min to obtain a uniformly dispersed PTFE suspension. WO3-BN and PTFE suspension were mixed in a mass ratio of WO3-BN:PTFE:APTES = 4:1:2, and silane coupling agent γ-aminopropyltriethoxysilane (APTES) was added. The mixture was stirred at room temperature for 2 h and dried to obtain a modified nanocomposite material.

[0030] (3) Ultra-high molecular weight polyethylene with a viscosity-average molecular weight of 2 million, modified nano-composite material, antioxidant 1010 and antioxidant 168 are put into a twin-screw extruder in a mass ratio of ultra-high molecular weight polyethylene, modified nano-composite material, antioxidant 1010 and antioxidant 168 = 90:3:0.1:0.5 for melting, mixing, conveying and shearing. The materials are then melt-spun and extruded at 280° C. and cooled in a water bath at 30° C. to obtain spun fibers. The spun fibers are subjected to three-stage heat stretching and winding, wherein the first stage stretching is 5 times stretching at 70° C., the second stage stretching is 3 times stretching at 100° C. and the third stage stretching is 2 times stretching at 130° C. to obtain modified ultra-high molecular weight polyethylene stab-resistant fibers.

[0031] This embodiment also provides a modified ultra-high molecular weight polyethylene stab-resistant fiber prepared by the above method.

[0032] Example 2

[0033] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber comprises the following steps:

[0034] (1) Boron nitride was dissolved in 5 mol / L sodium hydroxide solution, stirred at 120°C for 20 h, filtered, rinsed with deionized water, and dried to obtain surface hydroxylated BN; mesoporous WO3 and surface hydroxylated BN were added to ethanol at a mass ratio of WO3:BN=1:0.6, and ultrasonically dispersed for 2.5 h. The mixed solution was transferred to a hydrothermal reactor, deionized water was added (the volume ratio of deionized water to the above ethanol was 1:2.5), and stirred at 190°C for 2.5 h. After cooling to room temperature, it was filtered, washed, and dried to obtain WO3-BN.

[0035] (2) PTFE nanoparticles were dispersed in deionized water and dispersed by ultrasonic for 30 min to obtain a uniformly dispersed PTFE suspension. WO3-BN and PTFE suspension were mixed in a mass ratio of WO3-BN:PTFE:APTES = 5:1:1, and silane coupling agent γ-aminopropyltriethoxysilane (APTES) was added. The mixture was stirred at room temperature for 2.5 h and dried to obtain a modified nanocomposite material.

[0036] (3) Ultra-high molecular weight polyethylene with a viscosity-average molecular weight of 2 million, modified nano-composite material, antioxidant 1010 and antioxidant 168 are put into a twin-screw extruder in a mass ratio of ultra-high molecular weight polyethylene, modified nano-composite material, antioxidant 1010 and antioxidant 168 = 100:4:0.3:0.1 for melting, mixing, conveying and shearing. The materials are then melt-spun and extruded at 310° C. and cooled in a water bath at 40° C. to obtain spun fibers. The spun fibers are subjected to three-stage stretching and winding, wherein the first-stage stretching is 3 times stretching at 80° C., the second-stage stretching is 2 times stretching at 110° C. and the third-stage stretching is 1.5 times stretching at 130° C. to obtain modified ultra-high molecular weight polyethylene stab-resistant fibers.

[0037] This embodiment also provides a modified ultra-high molecular weight polyethylene stab-resistant fiber prepared by the above method.

[0038] Example 3

[0039] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber comprises the following steps:

[0040] (1) BN was added to a 3 mol / L sodium hydroxide solution, stirred at 120°C for 15 h, filtered, rinsed with deionized water, and dried to obtain surface hydroxylated BN; mesoporous WO3 and surface hydroxylated BN were added to ethanol at a mass ratio of WO3:BN=1:0.8, ultrasonically dispersed for 2 h, and the mixture was transferred to a hydrothermal reactor, deionized water was added (the volume ratio of deionized water to the above ethanol was 1:2), and stirred at 190°C for 3 h. After cooling to room temperature, WO3-BN was filtered, washed, and dried.

[0041] (2) Disperse PTFE nanoparticles in deionized water and use ultrasonic dispersion for 30 min to obtain a uniformly dispersed PTFE suspension. Mix WO3-BN and PTFE suspension in a mass ratio of WO3-BN:PTFE:APTES = 5:1:2, add silane coupling agent APTES, stir at room temperature for 3 h, and dry to obtain a modified nanocomposite material.

[0042] (3) Ultra-high molecular weight polyethylene with a viscosity-average molecular weight of 3 million, modified nano-composite material, antioxidant 1010 and antioxidant 168 are put into a twin-screw extruder in a mass ratio of ultra-high molecular weight polyethylene, modified nano-composite material, antioxidant 1010 and antioxidant 168 = 100:5:0.5:0.3 for melting, mixing, conveying and shearing. The materials are then melt-spun and extruded at 300° C. and cooled in a water bath at 30° C. to obtain spun fibers. The spun fibers are subjected to three-stage stretching and winding, wherein the first-stage stretching is 6 times stretching at 90° C., the second-stage stretching is 5 times stretching at 120° C. and the third-stage stretching is 3 times stretching at 135° C. to obtain modified ultra-high molecular weight polyethylene stab-resistant fibers.

[0043] This embodiment also provides a modified ultra-high molecular weight polyethylene stab-resistant fiber prepared by the above method.

[0044] Comparative Example 1

[0045] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber is basically the same as that of Example 1, except that step (1) is omitted and WO3-BN in step (2) is replaced by WO3.

[0046] Comparative Example 2

[0047] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber is basically the same as that in Example 1, except that step (1) is omitted and WO3-BN in step (2) is replaced by BN.

[0048] Comparative Example 3

[0049] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber is basically the same as that of Example 1, except that step (1) is omitted, and WO3-BN in step (2) is replaced by WO3 and BN, and the mass ratio of WO3 to BN is 1:0.5.

[0050] Comparative Example 4

[0051] A method for preparing a modified ultra-high molecular weight polyethylene stab-resistant fiber is basically the same as that of Example 1, except that the PTFE in step (2) is omitted.

[0052] Test example

[0053] The products prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to the following performance tests:

[0054] (1) Stab resistance test: The fibers obtained in Examples 1-3 and Comparative Examples 1-4 were woven into fabrics, and their puncture strength was measured using an INSTRON-3365 universal material mechanics testing machine in accordance with GA68-2019 "Police Anti-Stab Clothing". During the experiment, the tool speed was 10 mm / min, the fabric size was 150 mm × 150 mm, and the effective size of the clamp was 30 mm × 8 mm. The test results are shown in Table 1.

[0055] (2) Mechanical property test: The tensile strength and tensile modulus of the fibers obtained in Examples 1-3 and Comparative Examples 1-4 were tested on a LLY-06E single fiber strength tester. The interval between the upper and lower clamps was 20 mm, the tensile speed was 20 mm / min, the test temperature was room temperature, and each sample was tested more than 20 times. The results were averaged. The test results are shown in Table 1.

[0056] (3) Cutting resistance and abrasion resistance test: Cutting resistance and abrasion resistance test were carried out using the method in EN388-Mechanical Hazard Protection Standard. The results are shown in Table 1.

[0057] Table 1 Performance test results of the fibers or fabrics obtained from Examples 1-3 and Comparative Examples 1-4

[0058]

[0059] The results in Table 1 show that the modified ultra-high molecular weight polyethylene stab-resistant fibers prepared in Examples 1-3 of the present invention have excellent puncture resistance, cut resistance and wear resistance.

[0060] In Comparative Example 1, WO3-BN is replaced by WO3, in Comparative Example 2, WO3-BN is replaced by BN, and in Comparative Example 3, WO3-BN is replaced by WO3 and BN. Compared with Comparative Examples 1-3, the fibers of Examples 1-3 show better performance in puncture strength, tensile strength, tensile modulus, cut resistance and wear resistance, which indicates that the combination of BN with excellent mechanical properties and hardness and mesoporous WO3 forms a stable WO3-BN composite material, and the synergistic effect of BN and WO3 in the composite material can significantly improve the overall performance of the fiber.

[0061] Comparative Example 4 omitted PTFE, and compared with Examples 1-3, the overall performance of its fiber was reduced, among which the wear resistance was significantly reduced. This shows that PTFE plays an important role in the modified nanocomposite material. The addition of PTFE can not only enhance the bonding force between the components inside the fiber, but also reduce the wear of the fiber during the friction process due to its own lubricating properties, thereby improving the overall wear resistance of the fiber.

[0062] The above are only preferred embodiments of the present invention, and are not limited to the above examples. For those skilled in the art, various changes and variations are possible under the principle of the present invention. Any modifications and improvements made should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a modified supermolecular weight polyethylene stab-resistant fiber, characterized in that: The following steps are involved: (1) adding mesoporous WO3 and surface hydroxylated BN into ethanol for ultrasonic dispersion, then adding water for heating and stirring, cooling to room temperature, filtering, washing and drying to obtain WO3-BN; (2) mixing WO3-BN with PTFE suspension, adding silane coupling agent and stirring, filtering and drying to obtain a modified nanocomposite material; (3) placing ultra-molecular weight polyethylene, modified nanocomposite materials, antioxidant 1010 and antioxidant 168 into a twin-screw extruder for melting, mixing, conveying and shearing, extruding by melt spinning and cooling in a water bath to obtain nascent fibers; after the nascent fibers are subjected to three-stage heat stretching and winding, the modified ultra-molecular weight polyethylene stab-resistant fibers are obtained; In step (1), the mass ratio of the mesoporous WO3 to the surface hydroxylated BN is 1:0.5-0.8; the volume ratio of the ethanol to water is 2-2.5:1; The mass ratio of WO3-BN, PTFE and silane coupling agent in step (2) is 4-5:1:1-2; the stirring time is 2-3h; the silane coupling agent is 3-aminopropyltriethoxysilane; In step (3), the mass ratio of supermolecular weight polyethylene, modified nanocomposite material, antioxidant 1010 and antioxidant 168 is (90-100):(3-5):(0.1-0.5):(0.1-0.5).

2. The method for preparing the modified supermolecular weight polyethylene stab-resistant fiber according to claim 1, characterized in that: The ultrasonic dispersion in step (1) is carried out for 2-2.5 h; the heating and stirring is carried out at a temperature of 180-190°C for 2-3 h.

3. The method for preparing the modified supermolecular weight polyethylene stab-resistant fiber according to claim 1, characterized in that: The preparation method of the surface hydroxylated BN in step (1) is as follows: adding BN to a sodium hydroxide solution, stirring at 110-120° C. for 10-20 h, filtering, washing and drying to obtain the BN.

4. The method for preparing the modified supermolecular weight polyethylene stab-resistant fiber according to claim 1, characterized in that: The preparation method of mesoporous tungsten trioxide in step (1) is as follows: KIT-6 is dispersed in ethanol as a silicon-based template, phosphotungstic acid is added and stirred, the solvent is evaporated and the solid is calcined, and the calcined product is then removed from the silicon substrate with HF to obtain mesoporous WO3.

5. The method for preparing the modified supermolecular weight polyethylene stab-resistant fiber according to claim 1, characterized in that: The three-stage heat stretching in step (3) is specifically as follows: the temperature of the first stage stretching is 70-90°C, and the multiple is 3-6 times; the temperature of the second stage stretching is 100-120°C, and the multiple is 2-5 times; the temperature of the third stage stretching is 130-135°C, and the multiple is 1.5-3 times.

6. The method for preparing the modified supermolecular weight polyethylene stab-resistant fiber according to claim 1, characterized in that: The temperature of the melt spinning extrusion in step (3) is 280-310°C, and the temperature of the water bath cooling is 30-40°C.

7. The modified supermolecular weight polyethylene stab-resistant fiber obtained according to the preparation method described in any one of claims 1 to 6.

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