High-strength polyolefin monofilament and preparation method thereof

Abstract

The invention relates to a high-strength polyolefin monofilament and a preparation method thereof, and belongs to the technical field of high polymer materials. The high-strength polyolefin monofilament is prepared from the following raw materials in parts by weight: 60 to 90 parts of polyolefin, 10 to 12 parts of modified aramid fiber, 13 to 15 parts of modified alumina fiber, 0.6 to 0.8 part of stabilizer and 0.2 to 0.4 part of coupling agent. The modified alumina fiber is subjected to acid soaking and epoxy resin treatment, surface modification by functional groups is achieved, the binding force of an alumina fiber interface and a polyethylene interface is improved, meanwhile, the modified aramid fiber has a compact network structure, and the impact resistance of the modified alumina fiber in the vertical direction is greatly improved; in addition, the monofilament is extruded through a blade type melt pulsating pump, the orientation of the modified alumina fibers is arranged in the extrusion direction, and therefore the polyolefin monofilament prepared through the method has good tensile strength and abrasion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to a high-strength polyolefin monofilament and a preparation method thereof. Background Art

[0002] Common polyolefin synthetic resins include polyethylene, polypropylene, and ethylene-vinyl acetate copolymer. Polypropylene, a non-toxic, odorless, milky white, highly crystalline, general-purpose synthetic resin polymer, has high crystallinity and a regular structure, resulting in excellent mechanical properties. However, its mechanical properties are still relatively low among plastic materials, with a tensile strength of only 30 MPa or slightly higher. Polypropylene with a high isotactic index has higher tensile strength, but as the isotactic index increases, the material's notched impact strength decreases.

[0003] Alumina fiber has high strength, high modulus, and high tensile strength at high temperatures. The raw material cost of alumina fiber is low and the production process is simple, so alumina fiber has a relatively high cost-effectiveness and huge commercial value. Currently, there is relatively little research on alumina fiber in resins, and its interfacial bonding performance with polymers is poor.

[0004] Therefore, the high-strength polyolefin monofilament and the preparation method thereof disclosed in the present invention can effectively solve the above problems. Summary of the Invention

[0005] The present invention relates to a high-strength polyolefin monofilament and a preparation method thereof, and belongs to the technical field of polymer materials. The high-strength polyolefin monofilament disclosed in the present invention comprises the following raw materials in parts by weight: 60-90 parts of polyolefin, 10-12 parts of modified aramid fiber, 13-15 parts of modified alumina fiber, 0.6-0.8 parts of stabilizer, and 0.2-0.4 parts of coupling agent. The modified alumina fiber is acid-soaked and epoxy resin-treated to achieve functional group modification of its surface, thereby enhancing the bonding strength between the alumina fiber interface and the polyethylene interface. At the same time, the modified aramid has a tight network structure, which greatly improves the impact resistance of the modified alumina fiber in the vertical direction. In addition, the monofilament is extruded by a blade-type melt pulsating pump to achieve the orientation of the modified alumina fiber along the extrusion direction. Therefore, the polyolefin monofilament prepared by the present invention has good tensile strength and wear resistance.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A high-strength polyolefin monofilament comprises the following raw materials in parts by weight: 60-90 parts of polyolefin, 10-12 parts of modified aramid fiber, 13-15 parts of modified alumina fiber, 0.6-0.8 parts of stabilizer, and 0.2-0.4 parts of coupling agent, wherein the polyolefin is composed of polypropylene and polyethylene in a mass ratio of 2:1-2.

[0007] Furthermore, the preparation method of the modified aramid fiber comprises the following steps: (1) Dispersing the chopped aramid fibers in a composite liquid and stirring at high speed to obtain a mixed liquid; (2) The mixed liquid is then poured into a papermaking machine to remove moisture, dried, and chopped to obtain modified aramid fiber.

[0008] Furthermore, in step (1), the solid-liquid ratio of the chopped aramid fiber to the composite liquid is 5-10 g:30-40 mL, wherein the composite liquid is composed of a polyethylene oxide solution and deionized water in a volume ratio of 1:5, the mass fraction of the polyethylene oxide solution is 1-2%, and the speed and time of the high-speed stirring are 800-1000 r / min and 8-10 min, respectively.

[0009] Furthermore, the drying temperature and time in step (2) are 80-100° C. and 20-30 min, respectively, and the size of the modified aramid fiber is 0.2-0.3 mm×0.1-0.2 mm×5 μm.

[0010] Furthermore, the preparation method of the modified alumina fiber comprises the following steps: a1: completely immerse alumina fibers in nitric acid, filter, wash the solid with distilled water until neutral, and dry to obtain pretreated alumina fibers; a2: Anhydrous ethanol and KH560 silane coupling agent are mixed, and then pretreated alumina fiber is added and mixed and stirred, and then dried to obtain solid a; a3: Soak solid a in the mixed liquid, filter it, and bake solid b in a vacuum drying oven to obtain modified alumina fiber.

[0011] Furthermore, in step a1, the solid-liquid ratio of the alumina fiber to nitric acid is 1-3 g:8 mL, wherein the mass fraction of nitric acid is 30-35%, the immersion time is 2-3 h, the ratio of anhydrous ethanol, silane coupling agent and pretreated alumina fiber in step a2 is 20-30:0.05-0.08:2-4, and the mixing and stirring time is 60-120 min.

[0012] Furthermore, the immersion time in step a3 is 2-3h, the solid-liquid ratio of the solid a to the mixed liquid is 3-5g:20mL, the mixed liquid is composed of E-51 epoxy resin solution and acetone in a mass ratio, wherein the mass fraction of the E-51 epoxy resin solution is 8-10%, the baking temperature and time are 100-110°C and 3h, respectively, and the length and diameter of the modified alumina fiber are 0.5-1mm and 10μm, respectively.

[0013] A method for preparing high-strength polyolefin monofilaments comprises the following steps: placing all parts by weight of raw materials into a high-speed mixer, mixing for 8-10 minutes at a temperature of 170-200°C and a rotation speed of 750-850 r / min, then placing the raw materials into a blade-type melt pulsating pumping device for roller pressing, and then passing the materials into an extruder through a pipeline to extrude the monofilaments.

[0014] Furthermore, the temperature, rotation speed and time of the blade-type melt pulsating pumping device are 200-220°C, 30-35r / min, and 8-10min respectively, and the temperature of the extruder is 190-200°C.

[0015] Beneficial effects of the present invention: 1. The modified alumina fiber is acid-soaked and epoxy resin-treated to achieve functional group modification on its surface, which enhances the bonding strength between the alumina fiber interface and the polyethylene interface, thereby enhancing the wear resistance of polyolefin; 2. The monofilaments are extruded through a blade-type melt pulsating pump, so that the orientation of the modified alumina fibers is arranged along the extrusion direction, which greatly improves the tensile strength of the polyolefin monofilaments. At the same time, the modified aramid is added, which has a tight network structure and elasticity, greatly improving the impact resistance of the modified alumina fibers in the vertical direction. The modified alumina fibers and the modified aramid fibers form a dual load-bearing effect. Therefore, the polyolefin monofilaments prepared by the present invention have good tensile strength and wear resistance. DETAILED DESCRIPTION

[0016] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0017] The stabilizer involved in the present invention is antioxidant 1010; the coupling agent is KH550 silane coupling agent; polypropylene was purchased from Pingxiang Tiansheng Chemical Equipment Co., Ltd., specification 125Y; polyethylene was purchased from Shanghai Qiaowei Chemical Technology Co., Ltd., brand DFDA-7042; short-cut aramid fiber was purchased from Jiangxi Shuobang New Materials Technology Co., Ltd.; polyethylene oxide was purchased from Wuhan Shuer Biotechnology Co., Ltd., CAS number 68441-17-8; alumina fiber was purchased from Chongqing Canyue New Materials Co., Ltd.

[0018] Example 1

[0019] A high-strength polyolefin monofilament comprises the following raw materials in parts by weight: 60 parts of polyolefin, 10 parts of modified aramid fiber, 13 parts of modified alumina fiber, 0.6 parts of a stabilizer, and 0.2 parts of a coupling agent, wherein the polyolefin is composed of polypropylene and polyethylene in a mass ratio of 2:1.

[0020] The preparation method of the modified aramid fiber comprises the following steps: (1) Dispersing the chopped aramid fibers in a composite liquid and stirring at high speed to obtain a mixed liquid; (2) The mixed liquid is then poured into a papermaking machine to remove moisture, dried, and chopped to obtain modified aramid fiber.

[0021] In the step (1), the solid-liquid ratio of the chopped aramid fiber to the composite liquid is 5 g:30 mL, wherein the composite liquid is composed of a polyethylene oxide solution and deionized water in a volume ratio of 1:5, the mass fraction of the polyethylene oxide solution is 1%, and the speed and time of the high-speed stirring are 800 r / min and 8 min, respectively.

[0022] The drying temperature and time in step (2) are 80° C. and 20 min, respectively. The size of the modified aramid fiber is 0.2 mm×0.1 mm×5 μm.

[0023] The preparation method of the modified alumina fiber comprises the following steps: a1: completely immerse alumina fibers in nitric acid, filter, wash the solid with distilled water until neutral, and dry to obtain pretreated alumina fibers; a2: Anhydrous ethanol and KH560 silane coupling agent are mixed, and then pretreated alumina fiber is added and mixed and stirred, and then dried to obtain solid a; a3: Soak solid a in the mixed liquid, filter it, and bake solid b in a vacuum drying oven to obtain modified alumina fiber.

[0024] In step a1, the solid-liquid ratio of the alumina fiber to nitric acid is 1 g:8 mL, wherein the mass fraction of the nitric acid is 30%, the immersion time is 2 h, the ratio of anhydrous ethanol, silane coupling agent and pretreated alumina fiber in step a2 is 20:0.05:2, and the mixing and stirring time is 60 min.

[0025] The immersion time in step a3 is 2 hours, the solid-liquid ratio of the solid a to the mixed liquid is 3 g:20 mL, the mixed liquid is composed of E-51 epoxy resin solution and acetone in a mass ratio, wherein the mass fraction of the E-51 epoxy resin solution is 8%, the baking temperature and time are 100°C and 3 hours, respectively, and the length and diameter of the modified alumina fiber are 0.5 mm and 10 μm, respectively.

[0026] The preparation method of the high-strength polyolefin monofilament is as follows: all parts by weight of raw materials are placed in a high-pressure mixer, mixed at a temperature of 170° C. and a speed of 750 r / min for 8 minutes, then placed in a blade-type melt pulsating pumping device for roller pressing, and then passed into an extruder through a pipeline to extrude the monofilament.

[0027] The temperature, rotation speed and time of the blade-type melt pulsating pumping device are 200°C, 30 r / min and 8 min respectively, and the temperature of the extruder is 190°C.

[0028] Example 2

[0029] A high-strength polyolefin monofilament comprises the following raw materials in parts by weight: 75 parts of polyolefin, 11 parts of modified aramid fiber, 14 parts of modified alumina fiber, 0.7 parts of a stabilizer, and 0.3 parts of a coupling agent, wherein the polyolefin is composed of polypropylene and polyethylene in a mass ratio of 2:1.5.

[0030] The preparation method of the modified aramid fiber comprises the following steps: (1) Dispersing the chopped aramid fibers in a composite liquid and stirring at high speed to obtain a mixed liquid; (2) The mixed liquid is then poured into a papermaking machine to remove moisture, dried, and chopped to obtain modified aramid fiber.

[0031] In the step (1), the solid-liquid ratio of the chopped aramid fiber to the composite liquid is 7 g:35 mL, wherein the composite liquid is composed of a polyethylene oxide solution and deionized water in a volume ratio of 1:5, the mass fraction of the polyethylene oxide solution is 1%, and the speed and time of the high-speed stirring are 900 r / min and 9 min, respectively.

[0032] The drying temperature and time in step (2) are 90° C. and 25 min, respectively. The size of the modified aramid fiber is 0.2 mm×0.2 mm×5 μm.

[0033] The preparation method of the modified alumina fiber comprises the following steps: a1: completely immerse alumina fibers in nitric acid, filter, wash the solid with distilled water until neutral, and dry to obtain pretreated alumina fibers; a2: Anhydrous ethanol and KH560 silane coupling agent are mixed, and then pretreated alumina fiber is added and mixed and stirred, and then dried to obtain solid a; a3: Soak solid a in the mixed liquid, filter it, and bake solid b in a vacuum drying oven to obtain modified alumina fiber.

[0034] In step a1, the solid-liquid ratio of the alumina fiber to nitric acid is 2 g:8 mL, wherein the mass fraction of the nitric acid is 33%, the immersion time is 2.5 h, the ratio of anhydrous ethanol, silane coupling agent and pretreated alumina fiber in step a2 is 25:0.07:3, and the mixing and stirring time is 90 min.

[0035] The immersion time in step a3 is 2.5 hours, the solid-liquid ratio of the solid a to the mixed liquid is 4 g:20 mL, the mixed liquid is composed of E-51 epoxy resin solution and acetone in a mass ratio, wherein the mass fraction of the E-51 epoxy resin solution is 9%, the baking temperature and time are 105°C and 3 hours, respectively, and the length and diameter of the modified alumina fiber are 0.7 mm and 10 μm, respectively.

[0036] The preparation method of the high-strength polyolefin monofilament is as follows: all parts by weight of raw materials are placed in a high-speed mixer, mixed at a temperature of 185° C. and a speed of 800 r / min for 9 minutes, then placed in a blade-type melt pulsating pumping device for roller pressing, and then passed into an extruder through a pipeline to extrude the monofilament.

[0037] The temperature, rotation speed and time of the blade-type melt pulsating pumping device are 210°C, 33 r / min and 9 min respectively, and the temperature of the extruder is 195°C.

[0038] Example 3

[0039] A high-strength polyolefin monofilament comprises the following raw materials in parts by weight: 90 parts of polyolefin, 12 parts of modified aramid fiber, 15 parts of modified alumina fiber, 0.8 parts of a stabilizer, and 0.4 parts of a coupling agent, wherein the polyolefin is composed of polypropylene and polyethylene in a mass ratio of 2:2.

[0040] The preparation method of the modified aramid fiber comprises the following steps: (1) Dispersing the chopped aramid fibers in a composite liquid and stirring at high speed to obtain a mixed liquid; (2) The mixed liquid is then poured into a papermaking machine to remove moisture, dried, and chopped to obtain modified aramid fiber.

[0041] In the step (1), the solid-liquid ratio of the chopped aramid fiber to the composite liquid is 10 g:40 mL, wherein the composite liquid is composed of a polyethylene oxide solution and deionized water in a volume ratio of 1:5, the mass fraction of the polyethylene oxide solution is 2%, and the speed and time of the high-speed stirring are 1000 r / min and 10 min, respectively.

[0042] The drying temperature and time in step (2) are 100° C. and 30 min, respectively. The size of the modified aramid fiber is 0.3 mm×0.2 mm×5 μm.

[0043] The preparation method of the modified alumina fiber comprises the following steps: a1: completely immerse alumina fibers in nitric acid, filter, wash the solid with distilled water until neutral, and dry to obtain pretreated alumina fibers; a2: Anhydrous ethanol and KH560 silane coupling agent are mixed, and then pretreated alumina fiber is added and mixed and stirred, and then dried to obtain solid a; a3: Soak solid a in the mixed liquid, filter it, and bake solid b in a vacuum drying oven to obtain modified alumina fiber.

[0044] In step a1, the solid-liquid ratio of the alumina fiber to nitric acid is 3g:8mL, wherein the mass fraction of the nitric acid is 35%, the immersion time is 3h, the ratio of anhydrous ethanol, silane coupling agent and pretreated alumina fiber in step a2 is 30:0.08:4, and the mixing and stirring time is 120min.

[0045] The immersion time in step a3 is 3 hours, the solid-liquid ratio of the solid a to the mixed liquid is 5 g:20 mL, the mixed liquid is composed of E-51 epoxy resin solution and acetone in a mass ratio, wherein the mass fraction of the E-51 epoxy resin solution is 10%, the baking temperature and time are 110°C and 3 hours, respectively, and the length and diameter of the modified alumina fiber are 1 mm and 10 μm, respectively.

[0046] The preparation method of the high-strength polyolefin monofilament is as follows: all parts by weight of raw materials are placed in a high-pressure mixer, mixed at a temperature of 200° C. and a speed of 850 r / min for 10 minutes, then placed in a blade-type melt pulsating pumping device for roller pressing, and then passed into an extruder through a pipeline to extrude the monofilament.

[0047] The temperature, rotation speed and time of the blade-type melt pulsating pumping device are 220°C, 35 r / min and 10 min respectively, and the temperature of the extruder is 200°C.

[0048] Comparative Example 1 On the basis of Example 2, the step of placing the melt into a blade-type melt pulsating pumping device for rolling was removed, and the polyolefin monofilament was directly extruded through an extruder. Other conditions were the same as those in Example 2.

[0049] Comparative Example 2 On the basis of Example 2, step a1 for preparing the modified alumina fiber was removed, and steps a2-a3 were used to obtain the modified alumina fiber. Other conditions were the same as those in Example 2.

[0050] Comparative Example 3 On the basis of Example 2, the modified alumina fiber is obtained through step a1, steps a2-a3 are removed, and other conditions are consistent with Example 2.

[0051] Comparative Example 4 On the basis of Example 2, aramid fiber was used instead of modified aramid fiber, and the direct method of modified aramid fiber was removed. Other conditions were consistent with Example 2.

[0052] Performance Testing Polyolefin monofilaments prepared in Examples 1-3 and Comparative Examples 1-4 with an equal length diameter of 0.2 mm were taken as samples, and the tensile strength and elongation at break of the samples were tested according to the method in the national standard GB / T14344-2008; the samples were subjected to abrasion resistance testing according to ISO6722, and the number of abrasion tests before breakage was recorded. The results are shown in Table 1.

[0053] Table 1 Sample Tensile strength cN / dtex Elongation at break % Wear times / times Example 1 4.89 30.12 11032 Example 2 4.91 30.08 11230 Example 3 4.85 30.14 10923 Comparative Example 1 4.23 34.55 7866 Comparative Example 2 4.18 35.87 6598 Comparative Example 3 3.88 38.67 5320 Comparative Example 4 4.12 34.45 7852 From the results of Table 1, it can be concluded that the tensile strength of Examples 1-3 is greater than that of Comparative Examples 1-4, and the mechanical strength range is 4.85-4.91. Examples 1-3 are more wear-resistant than Comparative Examples 1-4, and the number of wear resistance exceeds 10,000 times. Comparative Example 1 did not undergo the rolling step in the blade-type melt pulsating pumping device, and the arrangement and orientation of the modified alumina fiber were chaotic, the force was dispersed, and thus the tensile strength was weakened, and the wear resistance was also reduced; Comparative Examples 2-3 reduced the surface modification functional groups of the alumina fiber, which reduced the interfacial bonding force between the modified alumina fiber and the polyolefin, thereby weakening the wear resistance and tensile strength; Comparative Example 4 used unmodified aramid fiber, which did not have a network structure, greatly reduced the tensile strength, and its elongation at break was smaller than that of Comparative Example 2. It can be found that the modified aramid fiber with a network structure not only improved the tensile strength but also improved the flexibility.

[0054] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-strength polyolefin monofilament, characterized in that: The high-strength polyolefin monofilament comprises the following raw materials in parts by weight: 60-90 parts of polyolefin, 10-12 parts of modified aramid fiber, 13-15 parts of modified alumina fiber, 0.6-0.8 parts of stabilizer, and 0.2-0.4 parts of coupling agent, wherein the polyolefin is composed of polypropylene and polyethylene in a mass ratio of 2:1-2.

2. The high-strength polyolefin monofilament according to claim 1, characterized in that: The preparation method of the modified aramid fiber comprises the following steps: (1) Dispersing the chopped aramid fibers in a composite liquid and stirring at high speed to obtain a mixed liquid; (2) The mixed liquid is then poured into a papermaking machine to remove moisture, dried, and chopped to obtain modified aramid fiber.

3. The high-strength polyolefin monofilament according to claim 2, characterized in that: In the step (1), the solid-liquid ratio of the chopped aramid fiber to the composite liquid is 5-10 g:30-40 mL, wherein the composite liquid is composed of a polyethylene oxide solution and deionized water in a volume ratio of 1:5, the mass fraction of the polyethylene oxide solution is 1-2%, and the speed and time of the high-speed stirring are 800-1000 r / min and 8-10 min, respectively.

4. The high-strength polyolefin monofilament according to claim 2, characterized in that: The drying temperature and time in step (2) are 80-100° C. and 20-30 min, respectively. The size of the modified aramid fiber is 0.2-0.3 mm×0.1-0.2 mm×5 μm.

5. The high-strength polyolefin monofilament according to claim 1, characterized in that: The preparation method of the modified alumina fiber comprises the following steps: a1: completely immerse alumina fibers in nitric acid, filter, wash the solid with distilled water until neutral, and dry to obtain pretreated alumina fibers; a2: Anhydrous ethanol and KH560 silane coupling agent are mixed, and then pretreated alumina fiber is added and mixed and stirred, and then dried to obtain solid a; a3: Soak solid a in the mixed liquid, filter it, and bake solid b in a vacuum drying oven to obtain modified alumina fiber.

6. The high-strength polyolefin monofilament according to claim 5, characterized in that: In step a1, the solid-liquid ratio of the alumina fiber to nitric acid is 1-3 g:8 mL, wherein the mass fraction of the nitric acid is 30-35%, the immersion time is 2-3 h, and the ratio of anhydrous ethanol, silane coupling agent and pretreated alumina fiber in step a2 is 20-30:0.05-0.08:2-4, and the mixing and stirring time is 60-120 min.

7. The high-strength polyolefin monofilament according to claim 5, characterized in that: The immersion time in step a3 is 2-3 hours, the solid-liquid ratio of the solid a to the mixed liquid is 3-5g:20mL, the mixed liquid is composed of E-51 epoxy resin solution and acetone in a mass ratio, wherein the mass fraction of the E-51 epoxy resin solution is 8-10%, the baking temperature and time are 100-110°C and 3 hours, respectively, and the length and diameter of the modified alumina fiber are 0.5-1mm and 10μm, respectively.

8. A method for preparing a high-strength polyolefin monofilament according to claim 1, characterized in that: The preparation method of the high-strength polyolefin monofilament is as follows: all parts by weight of raw materials are placed in a high-pressure mixer, mixed at a temperature of 170-200°C and a rotation speed of 750-850 r / min for 8-10 minutes, then placed in a blade-type melt pulsating pumping device for roller pressing, and then passed into an extruder through a pipeline to extrude the monofilament.

9. The method for preparing a high-strength polyolefin monofilament according to claim 8, characterized in that: The temperature, rotation speed and time of the blade-type melt pulsating pumping device are 200-220°C, 30-35r / min and 8-10min respectively, and the temperature of the extruder is 190-200°C.