Alumina fiber-containing cable outer sheath material with electromagnetic shielding function

Abstract

The invention relates to an alumina fiber-containing cable outer sheath material with an electromagnetic shielding function, and belongs to the technical field of cable preparation. The cable outer sheath material comprises the following raw materials: linear low-density polyethylene, electromagnetic shielding microspheres wrapped by alumina fibers, an aluminate coupling agent, an ethylene-vinyl acetate copolymer, an antioxidant 1076 and a polyolefin elastomer POE, the electromagnetic shielding microspheres wrapped by alumina fibers are introduced, and the electromagnetic shielding microspheres wrapped by alumina fibers are coated by a plurality of layers of metal coatings and alumina. The electromagnetic shielding performance of the outer sheath of the cable is further improved; in addition, the linear low-density polyethylene provides basic flexibility and environmental stress cracking resistance, the ethylene-vinyl acetate copolymer dispersive substance improves the cohesiveness and impact resistance of the material at the same time, and the polyolefin elastomer can enhance the low-temperature toughness and prolong the bending fatigue life; the components cooperate to meet the application requirements, and meanwhile, the cable outer sheath material with a good electromagnetic shielding effect is provided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cable preparation, and relates to an aluminum oxide fiber-containing cable outer sheath material with electromagnetic shielding. BACKGROUND

[0002] The cable outer sheath is a crucial part of the cable structure, and its main function is to protect the conductors and insulating materials inside the cable from the influence of the external environment, thereby prolonging the service life of the cable and ensuring the reliability and safety of the cable in extreme environments.

[0003] There are various types of materials for cable outer sheaths, which are applied in different environments based on different material properties, including cable outer sheaths with electromagnetic shielding effect. In order to meet the needs of the fields of information technology, communication, and high-frequency power transmission, research on cable outer sheaths with electromagnetic shielding effect is still ongoing. SUMMARY

[0004] The purpose of the present application is to provide an aluminum oxide fiber-containing cable outer sheath material with electromagnetic shielding. The present application introduces electromagnetic shielding microspheres wrapped in aluminum oxide fibers, which further improve the electromagnetic shielding performance of the cable outer sheath through multi-layer metal coating and aluminum oxide coating. In addition, the linear low-density polyethylene in the present application provides basic flexibility and environmental stress cracking resistance, the ethylene-vinyl acetate copolymer dispersion material simultaneously improves the adhesion and impact resistance of the material, and the polyolefin elastomer can enhance the low-temperature toughness and bending fatigue life. The components work together to meet the application requirements and provide a cable outer sheath material with good electromagnetic shielding effect.

[0005] The purpose of the present application can be achieved through the following technical solutions: The aluminum oxide fiber-containing cable outer sheath material with electromagnetic shielding comprises, by weight, 100-110 parts of linear low-density polyethylene, 20-30 parts of electromagnetic shielding microspheres wrapped in aluminum oxide fibers, 2.2-2.8 parts of aluminate coupling agent, 5-6 parts of ethylene-vinyl acetate copolymer, 0.6-1 part of antioxidant 1076, and 7.5-8.5 parts of polyolefin elastomer POE.

[0006] Further, the preparation method of the electromagnetic shielding microspheres wrapped in aluminum oxide fibers comprises the following steps: Step A1: Mix aluminum isopropoxide and ethanol in a mass ratio of 1:6-6.2, stir at 40℃ until dissolved, add a 62-68wt% nitric acid solution at a rate of 1mL / min, and stir for 24-36h to obtain a sol; Step A2, after mixing alumina fiber and electromagnetic shielding microspheres according to 2-3:1, immerse in sol, ultrasonic, electrostatic field treatment, centrifugal to remove excess sol, gradient drying, annealing, ready.

[0007] Further, the parameters of ultrasonic in step A2 are as follows: ultrasonic frequency is 30-50 kHz, ultrasonic power is 150-250 W, ultrasonic time is 8-12 min; the electrostatic field treatment refers to applying 9-11 kV / m direct current electric field for 14-16 min; the gradient drying refers to pre-drying at 80℃ oven for 0.8-1.2 h, and then drying at 120℃ oven for 25-35 min; the annealing refers to heating to 300-320℃ at 5℃ / min and keeping for 1-2 h under nitrogen atmosphere.

[0008] Further, the alumina fiber in step A2 needs to be pretreated, and the pretreatment comprises the following steps: Step B1, immerse alumina fiber in coupling agent-acetone solution after heating to 440-460℃ under nitrogen atmosphere, keep for 2-3 h, cool to room temperature, set ultrasonic frequency to 30-50 kHz, ultrasonic power to 300-400 W, ultrasonic for 20-40 min, and dry at 80℃ oven, ready.

[0009] Further, the heating rate in step B1 is 10-12℃ / min; the content of coupling agent in the coupling agent-acetone solution is 4-6 wt%; the coupling agent is aluminate coupling agent.

[0010] Further, the preparation method of electromagnetic shielding microspheres in step A2 comprises the following steps: Step C1, immerse glass fiber in nickel liquid, take out after stirring at 10-50 rpm for 30-40 min in 80℃ constant temperature water bath, wash, and dry at 60℃, to obtain nickel-loaded fiber; Step C2, load aluminum on the nickel-loaded fiber to obtain aluminum-nickel-loaded fiber; Step C3, immerse aluminum-nickel-loaded fiber in iron liquid, microwave treatment under nitrogen atmosphere, after completion, wash with anhydrous ethanol and deionized water alternately for 3 times, annealing treatment, to obtain electromagnetic shielding microspheres.

[0011] Further, the nickel liquid in step C1 is obtained by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride, deionized water according to mass ratio 0.4-0.5:0.2-0.3:0.05-0.06:0.008-0.012:93.5-95.5, and then adding triethanolamine to adjust pH to 8.4-8.6; the thickness of nickel layer of the nickel-loaded fiber is 0.8 μm.

[0012] Further, the loading of aluminum in step C2 refers to the arc spraying coating of aluminum layer, and the parameters of the arc spraying device are as follows: voltage is 30 V, current is 200 A, spraying distance is 150 mm, and spraying thickness is 1.2 μm.

[0013] Further, the iron liquid in step C3 is obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide and deionized water according to a mass ratio of 8.34-8.38:6-6.2:0.8-1.2:1.13-1.17:91-92; the parameters of the microwave treatment are as follows: power is 350-450 W, temperature is 74-76 ℃, and time is 28-32 min; and the annealing treatment refers to annealing at 245-255 ℃ for 0.8-1.2 h in a nitrogen atmosphere.

[0014] Further, the preparation method of the cable outer sheath material comprises the following steps: Step D1, the linear low density polyethylene is preheated to 85 ℃ to soften, then the electromagnetic shielding microspheres wrapped by aluminum oxide fibers, ethylene-vinyl acetate copolymer, aluminate coupling agent and antioxidant are added, and mixing is carried out at a speed of 300-400 rpm for 30-40 min, and extrusion granulation is carried out to obtain the cable outer sheath material.

[0015] The beneficial effects of the present application are as follows: (1) The present application introduces the electromagnetic shielding microspheres wrapped by aluminum oxide fibers, and the electromagnetic shielding performance of the cable outer sheath is further improved through the multi-layer metal coating and the aluminum oxide coating. In addition, the linear low density polyethylene in the present application provides basic flexibility and environmental stress cracking resistance, the ethylene-vinyl acetate copolymer dispersion material simultaneously improves the adhesion and impact resistance of the material, and the polyolefin elastomer can enhance the low temperature toughness and bending fatigue life. The components synergistically meet the application requirements and provide a cable outer sheath material with good electromagnetic shielding effect.

[0016] (2) The electromagnetic shielding microspheres in the present application take glass fibers as the core, the nickel layer reflects high frequency electromagnetic waves, the aluminum layer suppresses low frequency interference, and the iron layer absorbs medium frequency energy through eddy current loss, thereby improving the overall shielding efficiency. On this basis, the aluminum oxide fibers wrap the microspheres by sol-gel method to form a "fiber-microsphere" interpenetrating structure, which optimizes the conductive path. The conductive path generates induced current in the electromagnetic field, thereby generating a counteracting magnetic field to weaken the influence of external electromagnetic waves.

[0017] (3) The present application wraps electromagnetic shielding microspheres by means of aluminum isopropyl alcohol hydrolysis in ethanol and nitric acid solution to form aluminum hydroxide sol, uniformly wraps electromagnetic shielding microspheres and fibers, simultaneously applies an electrostatic field, and makes charged aluminum oxide fibers and sol particles directional arrangement, and further forms a uniform gel network, and the gel state aluminum oxide forms a dense aluminum oxide layer after drying, and further firmly combines the fibers and the microspheres, avoids cracks caused by uneven stress during the drying process, and further enhances the mechanical properties of the outer protective layer material, and the insulating property of the aluminum oxide fiber can isolate the metal plating layer, inhibit electrochemical corrosion, avoid oxidation failure of the metal plating layer, and make the cable outer protective layer play a stable electromagnetic shielding effect. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purpose, the specific embodiments, structures, features and effects according to the present application are described in detail as follows in combination with examples.

[0019] The linear low density polyethylene and the polyolefin elastomer POE in all examples and comparative examples of the present application are directly purchased from the market, and are all purchased from Shanghai Shengyiyuan Plastic Co., Ltd.; the aluminum isopropyl alcohol, the nickel sulfamate, the sodium citrate, the sodium saccharin, the urea, the antioxidant 1076 and the aluminate coupling agent are directly purchased from the market, and are all purchased from Shandong Guohua Chemical Co., Ltd.; the aluminum oxide fiber and the glass fiber are directly purchased from the market, and are all purchased from Fosman Technology (Beijing) Co., Ltd.; the sodium borohydride is directly purchased from the market, and is all purchased from Maoming Xiongdahua Chemical Co., Ltd.; the ferrous sulfate is directly purchased from the market, and is all purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; the hydrogen peroxide is directly purchased from the market, and is all purchased from Foshan Jiahe Chemical Co., Ltd.; the ethylene-vinyl acetate copolymer is directly purchased from the market, and is all purchased from Dongguan Shengli New Material Co., Ltd.

[0020] Example 1 The cable outer protective layer material with electromagnetic shielding and containing aluminum oxide fiber in the present embodiment includes 100 parts of linear low density polyethylene, 20 parts of electromagnetic shielding microspheres wrapped by aluminum oxide fiber, 2.2 parts of aluminate coupling agent, 5 parts of ethylene-vinyl acetate copolymer, 0.6 parts of antioxidant 1076 and 7.5 parts of polyolefin elastomer POE according to weight parts.

[0021] The preparation method of the electromagnetic shielding microspheres wrapped by aluminum oxide fiber in the present embodiment includes the following steps: Step A1, mix aluminum isopropyl alcohol and ethanol according to a mass ratio of 1:6, stir at 40℃ until dissolved, add a 62wt% nitric acid solution at a rate of 1mL / min, stir for 24h, and obtain a sol; Step A2, the alumina fiber, electromagnetic shielding microspheres are mixed according to 2:1, then immersed in the sol, ultrasonic, electrostatic field treatment, centrifugal removal of excess sol, gradient drying, annealing, ready.

[0022] The parameters of ultrasonic in step A2 of the embodiment are as follows: the ultrasonic frequency is 30 kHz, the ultrasonic power is 150 W, and the ultrasonic time is 12 min; the electrostatic field treatment refers to applying a direct current electric field of 9 kV / m for 14 min; the gradient drying refers to pre-drying at 80℃ for 0.8 h, and then drying at 120℃ for 25 min; the annealing refers to heating to 300℃ at a rate of 5℃ / min under a nitrogen atmosphere, and then keeping the temperature for 1 h.

[0023] The alumina fiber in step A2 of the embodiment needs to be pretreated, and the pretreatment includes the following steps: Step B1, under a nitrogen atmosphere, the alumina fiber is heated to 440℃, kept for 2 h, then cooled to room temperature, then immersed in a coupling agent-acetone solution, set the ultrasonic frequency to 30 kHz, the ultrasonic power to 300 W, and ultrasonic for 20 min, then dried at 80℃ to obtain the product.

[0024] The heating rate in step B1 of the embodiment is 10℃ / min; the content of the coupling agent in the coupling agent-acetone solution is 4wt%; the coupling agent is aluminate coupling agent.

[0025] The preparation method of the electromagnetic shielding microspheres in step A2 of the embodiment includes the following steps: Step C1, immerse the glass fiber in a nickel solution, stir at 10 rpm for 30 min in a 80℃ constant temperature water bath, then take out, wash, and dry at 60℃ to obtain the nickel-loaded fiber; Step C2, load aluminum on the nickel-loaded fiber to obtain the aluminum-nickel-loaded fiber; Step C3, immerse the aluminum-nickel-loaded fiber in an iron solution, perform microwave treatment under a nitrogen atmosphere, then wash with anhydrous ethanol and deionized water alternately for 3 times, and perform annealing treatment to obtain the electromagnetic shielding microspheres.

[0026] The nickel solution in step C1 of the embodiment is obtained by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride, and deionized water according to a mass ratio of 0.4:0.2:0.05:0.008:93.5, and then adding triethanolamine to adjust the pH to 8.4; the thickness of the nickel layer of the nickel-loaded fiber is 0.8μm.

[0027] The aluminum loading in step C2 of the embodiment refers to arc spraying to coat an aluminum layer, and the parameters of the arc spraying equipment are as follows: the voltage is 30 V, the current is 200 A, the spraying distance is 150 mm, and the spraying thickness is 1.2μm.

[0028] The iron liquid in step C3 of the embodiment is obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide and deionized water according to a mass ratio of 8.34:6:0.8:1.13:91; the microwave treatment parameters are: power of 350W, temperature of 74℃, and time of 28min; the annealing treatment refers to annealing at 245℃ for 0.8h under a nitrogen atmosphere.

[0029] The preparation method of the cable outer sheath material of the embodiment comprises the following steps: Step D1, after the linear low density polyethylene is preheated to 85℃ and softened, the alumina fiber wrapped electromagnetic shielding microspheres, ethylene-vinyl acetate copolymer, aluminate coupling agent, antioxidant are added, and mixed at a speed of 300rpm for 30min, extruded and granulated to obtain the cable outer sheath material.

[0030] Example 2 The cable outer sheath material with electromagnetic shielding and containing alumina fiber of the embodiment comprises, by weight, 103 parts of linear low density polyethylene, 22 parts of alumina fiber wrapped electromagnetic shielding microspheres, 2.4 parts of aluminate coupling agent, 5.1 parts of ethylene-vinyl acetate copolymer, 0.7 parts of antioxidant 1076, and 7.8 parts of polyolefin elastomer POE.

[0031] The preparation method of the alumina fiber wrapped electromagnetic shielding microspheres of the embodiment comprises the following steps: Step A1, after aluminum isopropoxide and ethanol are mixed according to a mass ratio of 1:6.08, stirring is performed at 40℃ until dissolution, a 64wt% nitric acid solution is added dropwise at a rate of 1mL / min, and stirring is performed for 28h to obtain a sol; Step A2, after alumina fiber and electromagnetic shielding microspheres are mixed according to a ratio of 2.2:1, they are immersed in the sol, ultrasonic treatment, electrostatic field treatment, centrifugal removal of excess sol, gradient drying, and annealing are performed.

[0032] The ultrasonic treatment parameters in step A2 of the embodiment are: ultrasonic frequency of 35kHz, ultrasonic power of 180W, and ultrasonic treatment for 8-12min; the electrostatic field treatment refers to applying a direct current electric field of 9kV / m for 14.7min; the gradient drying refers to pre-drying at 80℃ for 0.9h, and then drying at 120℃ for 28min; the annealing refers to heating to 305℃ at a rate of 5℃ / min under a nitrogen atmosphere, and maintaining the temperature for 1.2h.

[0033] The alumina fiber in step A2 of the embodiment needs to be pretreated, and the pretreatment comprises the following steps: Step B1, after the alumina fiber was heated to 445℃ under nitrogen atmosphere, it was kept for 2.3h, then cooled to room temperature, immersed in the coupling agent-acetone solution, set the ultrasonic frequency to 35kHz, ultrasonic power to 320W, ultrasonic for 25min, dried at 80℃ to obtain the product.

[0034] The heating rate in step B1 of this example was 10.5℃ / min; the content of coupling agent in the coupling agent-acetone solution was 4.5wt%; the coupling agent was aluminate coupling agent.

[0035] The preparation method of the electromagnetic shielding microspheres in step A2 of this example comprises the following steps: Step C1, the glass fiber was immersed in the nickel solution, stirred at 20rpm for 32min in 80℃ constant temperature water bath, then taken out, washed, dried at 60℃ to obtain the fiber loaded with nickel; Step C2, the fiber loaded with nickel was loaded with aluminum to obtain the fiber loaded with aluminum-nickel; Step C3, the fiber loaded with aluminum-nickel was immersed in the iron solution, microwave treated under nitrogen atmosphere, then washed with anhydrous ethanol and deionized water alternately for 3 times, annealed to obtain the electromagnetic shielding microspheres.

[0036] The nickel solution in step C1 of this example was obtained by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride and deionized water according to the mass ratio of 0.42:0.23:0.054:0.009:94, and then adding triethanolamine to adjust the pH to 8.4; the thickness of the nickel layer of the fiber loaded with nickel was 0.8μm.

[0037] The loading of aluminum in step C2 of this example refers to the arc spraying coating of aluminum layer, and the parameters of the arc spraying equipment were as follows: voltage was 30V, current was 200A, spraying distance was 150mm, and the spraying thickness was 1.2μm.

[0038] The iron solution in step C3 of this example was obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide and deionized water according to the mass ratio of 8.35:6.08:0.9:1.14:91.3; the parameters of microwave treatment were as follows: power was 380W, temperature was 74.5℃, and time was 29min; the annealing treatment refers to annealing at 248℃ under nitrogen atmosphere for 0.9h.

[0039] The preparation method of the cable outer sheath material of this example comprises the following steps: Step D1, after the linear low density polyethylene was preheated to 85℃ to soften, the electromagnetic shielding microspheres wrapped with alumina fiber, ethylene-vinyl acetate copolymer, aluminate coupling agent and antioxidant were added, mixed at 320rpm for 33min, extruded and granulated to obtain the cable outer sheath material.

[0040] Example 3 The cable outer sheath material with electromagnetic shielding of the alumina fiber-containing cable outer sheath material of the embodiment comprises, in parts by weight, 105 parts of linear low-density polyethylene, 25 parts of alumina fiber-wrapped electromagnetic shielding microspheres, 2.5 parts of aluminate coupling agent, 5.5 parts of ethylene-vinyl acetate copolymer, 0.8 parts of antioxidant 1076, and 8 parts of polyolefin elastomer POE.

[0041] The preparation method of the alumina fiber-wrapped electromagnetic shielding microspheres of the embodiment comprises the following steps: Step A1, after mixing aluminum isopropoxide and ethanol according to a mass ratio of 1:6.1, stirring at 40°C until dissolution, adding a 65wt% nitric acid solution at a rate of 1mL / min, and stirring for 30h, a sol is obtained; Step A2, after mixing alumina fibers and electromagnetic shielding microspheres according to a ratio of 2.5:1, immersing in the sol, ultrasonic treatment, electrostatic field treatment, centrifugal removal of excess sol, gradient drying, and annealing, the product is obtained.

[0042] The parameters of ultrasonic treatment in Step A2 of the embodiment are as follows: ultrasonic frequency is 40kHz, ultrasonic power is 200W, and ultrasonic treatment is performed for 10min; the electrostatic field treatment refers to applying a 10kV / m direct current electric field for 15min; the gradient drying refers to pre-drying in an 80°C oven for 1h and then drying in a 120°C oven for 30min; and the annealing refers to heating to 310°C at a rate of 5°C / min and then maintaining the temperature for 1.5h under a nitrogen atmosphere.

[0043] The alumina fibers in Step A2 of the embodiment need to be pretreated, and the pretreatment comprises the following steps: Step B1, under a nitrogen atmosphere, the alumina fibers are heated to 450°C, maintained for 2.5h, cooled to room temperature, then immersed in a coupling agent-acetone solution, ultrasonic treatment is performed at an ultrasonic frequency of 40kHz and an ultrasonic power of 350W for 30min, and then dried at 80°C to obtain the product.

[0044] The heating rate in Step B1 of the embodiment is 11°C / min; the content of the coupling agent in the coupling agent-acetone solution is 5wt%; and the coupling agent is an aluminate coupling agent.

[0045] The preparation method of the electromagnetic shielding microspheres in Step A2 of the embodiment comprises the following steps: Step C1, the glass fibers are immersed in a nickel solution, stirred at a speed of 30rpm in a 80°C constant-temperature water bath for 35min, then taken out, washed, and dried at 60°C to obtain the nickel-loaded fibers; Step C2, the nickel-loaded fibers are subjected to aluminum loading to obtain the aluminum-nickel-loaded fibers; Step C3, the aluminum-nickel loaded fiber was immersed in the iron liquid, and microwave treatment was carried out under a nitrogen atmosphere. After the end, the fiber was washed with anhydrous ethanol and deionized water alternately for 3 times, and annealing treatment was carried out, so as to obtain the electromagnetic shielding microspheres.

[0046] The nickel liquid in step C1 of the embodiment was obtained by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride and deionized water according to the mass ratio of 0.45:0.25:0.055:0.01:94.5, and then adding triethanolamine dropwise to adjust the pH to 8.5. The thickness of the nickel layer of the nickel-loaded fiber was 0.8 μm.

[0047] The aluminum loading in step C2 of the embodiment refers to arc spraying coating of the aluminum layer. The parameters of the arc spraying equipment were as follows: the voltage was 30 V, the current was 200 A, the spraying distance was 150 mm, and the spraying thickness was 1.2 μm.

[0048] The iron liquid in step C3 of the embodiment was obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide and deionized water according to the mass ratio of 8.36:6.1:1:1.15:91.5. The parameters of the microwave treatment were as follows: the power was 400 W, the temperature was 75 °C, and the time was 30 min. The annealing treatment refers to annealing at 250 °C for 1 h under a nitrogen atmosphere.

[0049] The preparation method of the cable outer sheath material of the embodiment comprises the following steps: Step D1, the linear low density polyethylene was preheated to 85 °C to soften, and then the electromagnetic shielding microspheres wrapped with aluminum oxide fiber, ethylene-vinyl acetate copolymer, aluminate coupling agent and antioxidant were added. Mixing was carried out at a speed of 350 rpm for 35 min, and extrusion granulation was carried out, so as to obtain the cable outer sheath material.

[0050] Example 4 The cable outer sheath material with electromagnetic shielding and containing aluminum oxide fiber of the embodiment comprises 107 parts of linear low density polyethylene, 26 parts of electromagnetic shielding microspheres wrapped with aluminum oxide fiber, 2.7 parts of aluminate coupling agent, 5.8 parts of ethylene-vinyl acetate copolymer, 0.9 parts of antioxidant 1076 and 8.2 parts of polyolefin elastomer POE.

[0051] The preparation method of the electromagnetic shielding microspheres wrapped with aluminum oxide fiber of the embodiment comprises the following steps: Step A1, aluminum isopropoxide and ethanol were mixed according to the mass ratio of 1:6.13, and then stirred to dissolve at 40 °C. A nitric acid solution with a mass concentration of 66 wt% was added dropwise at a rate of 1 mL / min, and stirring was carried out for 32 h, so as to obtain a sol. Step A2, after mixing alumina fiber and electromagnetic shielding microspheres according to 2.7:1, immerse in sol, ultrasonic, electrostatic field treatment, centrifugal to remove excess sol, gradient drying, annealing, and then the product is obtained.

[0052] The parameters of ultrasonic in step A2 of the example are as follows: ultrasonic frequency is 45 kHz, ultrasonic power is 230 W, and ultrasonic time is 11 min; electrostatic field treatment refers to applying 11 kV / m direct current electric field for 15.5 min; gradient drying refers to pre-drying in 80℃ oven for 1.1 h, and then drying in 120℃ oven for 33 min; annealing refers to heating to 315℃ at a rate of 5℃ / min under nitrogen atmosphere, and then keeping the temperature for 1.8 h.

[0053] The alumina fiber in step A2 of the example needs to be pretreated, and the pretreatment includes the following steps: Step B1, immerse the alumina fiber in coupling agent-acetone solution after heating to 455℃ under nitrogen atmosphere and keeping the temperature for 2.8 h, and then cooling to room temperature, and then set ultrasonic frequency to 30-50 kHz, ultrasonic power to 370 W, and ultrasonic time to 34 min, and then dry at 80℃, and then the product is obtained.

[0054] The heating rate in step B1 of the example is 11.5℃ / min; the content of coupling agent in the coupling agent-acetone solution is 5.3 wt%; and the coupling agent is aluminate coupling agent.

[0055] The preparation method of electromagnetic shielding microspheres in step A2 of the example includes the following steps: Step C1, immerse glass fiber in nickel liquid in 80℃ constant temperature water bath, stir at a speed of 40 rpm for 37 min, take out, wash, and dry at 60℃, and then the product of nickel-loaded fiber is obtained; Step C2, load aluminum on the nickel-loaded fiber, and then the product of aluminum-nickel-loaded fiber is obtained; Step C3, immerse the aluminum-nickel-loaded fiber in iron liquid, and then microwave treatment is carried out under nitrogen atmosphere, and then wash with anhydrous ethanol and deionized water alternately for 3 times, and then annealing treatment is carried out, and then the product of electromagnetic shielding microspheres is obtained.

[0056] The nickel liquid in step C1 of the example is obtained by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride, and deionized water according to a mass ratio of 0.46:0.28:0.059:0.011:95, and then add triethanolamine to adjust the pH to 8.6; and the thickness of the nickel layer of the nickel-loaded fiber is 0.8 μm.

[0057] The aluminum loading in step C2 of the example refers to arc spraying to coat aluminum layer, and the parameters of the arc spraying equipment are as follows: voltage is 30 V, current is 200 A, spraying distance is 150 mm, and the thickness of the sprayed layer is 1.2 μm.

[0058] The iron liquid in step C3 of the embodiment is obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide and deionized water according to a mass ratio of 8.37:6.16:1.1:1.16:91.7; the microwave treatment parameters are: power of 420 W, temperature of 75.3℃, and time of 31 min; the annealing treatment refers to annealing at 252℃ for 1.1 h under a nitrogen atmosphere.

[0059] The preparation method of the cable outer sheath material of the embodiment comprises the following steps: Step D1, after the linear low-density polyethylene is preheated to 85℃ and softened, the aluminum oxide fiber-wrapped electromagnetic shielding microspheres, ethylene-vinyl acetate copolymer, aluminate coupling agent, and antioxidant are added, mixed at a speed of 370 rpm for 36 min, extruded and granulated to obtain the cable outer sheath material.

[0060] Embodiment 5 The cable outer sheath material with electromagnetic shielding and containing aluminum oxide fibers comprises, by weight, 110 parts of linear low-density polyethylene, 30 parts of aluminum oxide fiber-wrapped electromagnetic shielding microspheres, 2.8 parts of aluminate coupling agent, 6 parts of ethylene-vinyl acetate copolymer, 1 part of antioxidant 1076, and 8.5 parts of polyolefin elastomer POE.

[0061] The preparation method of the aluminum oxide fiber-wrapped electromagnetic shielding microspheres of the embodiment comprises the following steps: Step A1, after aluminum isopropoxide and ethanol are mixed according to a mass ratio of 1:6.2, they are stirred to dissolve at 40℃, a 68wt% nitric acid solution is added dropwise at a rate of 1 mL / min, and stirring is performed for 36 h to obtain a sol; Step A2, after the aluminum oxide fibers and electromagnetic shielding microspheres are mixed according to a ratio of 3:1, they are immersed in the sol, ultrasonic treatment, electrostatic field treatment, centrifugal removal of excess sol, gradient drying, and annealing are performed to obtain the product.

[0062] The ultrasonic treatment parameters in step A2 of the embodiment are: ultrasonic frequency of 50 kHz, ultrasonic power of 250 W, and ultrasonic treatment for 12 min; the electrostatic field treatment refers to applying a direct current electric field of 11 kV / m for 16 min; the gradient drying refers to pre-drying at 80℃ for 1.2 h, and then drying at 120℃ for 35 min; the annealing refers to heating to 320℃ at a rate of 5℃ / min under a nitrogen atmosphere, and maintaining the temperature for 2 h.

[0063] The aluminum oxide fibers in step A2 of the embodiment need to be pretreated, and the pretreatment comprises the following steps: Step B1, after the alumina fiber was heated to 460℃ under nitrogen atmosphere, it was kept for 3h, then cooled to room temperature, and then immersed in the coupling agent-acetone solution, the ultrasonic frequency was set to 50 kHz, the ultrasonic power was 400 W, and the ultrasonic time was 40 min, and then dried at 80℃ to obtain the product.

[0064] The heating rate in step B1 of this example was 12℃ / min; the content of the coupling agent in the coupling agent-acetone solution was 6wt%; the coupling agent was aluminate coupling agent.

[0065] The preparation method of the electromagnetic shielding microspheres in step A2 of this example comprises the following steps: Step C1, the glass fiber was immersed in the nickel liquid, and then stirred at 50 rpm for 40 min in a constant temperature water bath at 80℃, then taken out, washed, and dried at 60℃ to obtain the fiber loaded with nickel; Step C2, the fiber loaded with nickel was loaded with aluminum to obtain the fiber loaded with aluminum-nickel; Step C3, the fiber loaded with aluminum-nickel was immersed in the iron liquid, and then subjected to microwave treatment under nitrogen atmosphere, and then washed with anhydrous ethanol and deionized water alternately for 3 times, and then subjected to annealing treatment to obtain the electromagnetic shielding microspheres.

[0066] The nickel liquid in step C1 of this example was obtained by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride, and deionized water according to the mass ratio of 0.5:0.3:0.06:0.012:95.5, and then adding triethanolamine dropwise to adjust the pH to 8.6; the thickness of the nickel layer of the fiber loaded with nickel was 0.8μm.

[0067] The loading of aluminum in step C2 of this example refers to the arc spraying coating of aluminum layer, and the parameters of the arc spraying equipment were as follows: the voltage was 30V, the current was 200A, the spraying distance was 150mm, and the spraying thickness was 1.2μm.

[0068] The iron liquid in step C3 of this example was obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide, and deionized water according to the mass ratio of 8.38:6.2:1.2:1.17:92; the parameters of the microwave treatment were as follows: the power was 450W, the temperature was 76℃, and the time was 32min; the annealing treatment referred to annealing at 255℃ for 1.2h under nitrogen atmosphere.

[0069] The preparation method of the cable outer sheath material of this example comprises the following steps: Step D1, after the linear low density polyethylene was preheated to 85℃ to soften, the electromagnetic shielding microspheres wrapped with alumina fiber, ethylene-vinyl acetate copolymer, aluminate coupling agent, and antioxidant were added, and then mixed at 400 rpm for 40 min, and then extruded and granulated to obtain the cable outer sheath material.

[0070] Example 6 On the basis of Example 3, the electromagnetic shielding microspheres wrapped by alumina fiber were removed, and equal weight of electromagnetic shielding microspheres was used to replace, and other conditions were kept consistent with Example 3.

[0071] Comparative Example 1 On the basis of Example 3, the alumina fiber was not pretreated, and other conditions were kept consistent with Example 3.

[0072] Comparative Example 2 On the basis of Example 3, other conditions were kept consistent, and the preparation method of electromagnetic shielding microspheres was changed to the following steps: Step C1, the glass fiber was loaded with aluminum to obtain the fiber loaded with aluminum; Step C2, the fiber loaded with aluminum was immersed in a nickel liquid, and was stirred at 80℃ constant temperature water bath at a speed of 30rpm for 35min, then was taken out, washed, and dried at 60℃ to obtain the fiber loaded with nickel-aluminum; Step C3, the fiber loaded with nickel-aluminum was immersed in an iron liquid, and was treated by microwave under nitrogen atmosphere, then was washed with anhydrous ethanol and deionized water alternately for 3 times, and was annealed to obtain electromagnetic shielding microspheres.

[0073] Comparative Example 3 On the basis of Example 3, other conditions were kept consistent, and the preparation method of electromagnetic shielding microspheres was changed to the following steps: Step C1, the glass fiber was immersed in a nickel liquid, and was stirred at 80℃ constant temperature water bath at a speed of 300rpm for 35min, then was taken out, washed, and dried at 60℃ to obtain the fiber loaded with nickel; Step C2, the fiber loaded with nickel was immersed in an iron liquid, and was treated by microwave under nitrogen atmosphere, then was washed with anhydrous ethanol and deionized water alternately for 3 times to obtain the fiber loaded with iron-nickel; Step C3, the fiber loaded with iron-nickel was loaded with aluminum, and was annealed to obtain electromagnetic shielding microspheres.

[0074] Comparative Example 4 On the basis of Example 3, other conditions were kept consistent, and the preparation method of electromagnetic shielding microspheres was changed to the following steps: Step C1, the glass fiber was loaded with aluminum to obtain the fiber loaded with aluminum; Step C2, the fiber loaded with aluminum was immersed in an iron liquid, and was treated by microwave under nitrogen atmosphere, then was washed with anhydrous ethanol and deionized water alternately for 3 times, and was annealed to obtain electromagnetic shielding microspheres.

[0075] Comparative Example 5 On the basis of Example 3, other conditions were kept consistent, and the preparation method of electromagnetic shielding microspheres was changed to the following steps: Step C1, immerse the glass fiber in the nickel liquid, in the constant temperature water bath at 80℃, stirring at 30rpm for 35min, then take out, wash, dry at 60℃, to obtain the nickel loaded fiber; Step C2, immerse the nickel loaded fiber in the iron liquid, microwave treatment under nitrogen atmosphere, after the end, wash with anhydrous ethanol and deionized water alternately for 3 times, annealing treatment, to obtain the electromagnetic shielding microspheres.

[0076] The cable outer sheath material prepared by examples 1-6 and comparative examples 1-5 is used as the sample, the electromagnetic shielding efficiency of the sample at 10MHz-1GHz is tested according to GB / T 30142-2013, and the test results are shown in the following table 1.

[0077] Table 1 As shown in table 1, the cable outer sheath material containing alumina fiber prepared by the application has good electromagnetic shielding efficiency.

[0078] The above is only the preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the application, and any indirect modification, equivalent change and modification of the above embodiment according to the technical essence of the application still belong to the scope of the application.

Claims

1. Alumina fiber-containing cable outer sheath material with electromagnetic shielding, characterized by: The raw materials of the cable outer sheath material include, by weight, 100-110 parts of linear low-density polyethylene, 20-30 parts of electromagnetic shielding microspheres wrapped with alumina fibers, 2.2-2.8 parts of aluminate coupling agent, 5-6 parts of ethylene-vinyl acetate copolymer, 0.6-1 part of antioxidant 1076, and 7.5-8.5 parts of polyolefin elastomer POE.

2. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 1, characterized in that: The preparation method of the electromagnetic shielding microspheres wrapped with alumina fibers comprises the following steps: Step A1: aluminum isopropoxide and ethanol are mixed in a mass ratio of 1:6-6.2, stirred at 40° C. until dissolved, and a nitric acid solution with a mass concentration of 62-68 wt % is added dropwise at a rate of 1 mL / min, and stirred for 24-36 h to obtain a sol; Step A2: Alumina fibers and electromagnetic shielding microspheres are mixed in a ratio of 2-3:1, immersed in a sol, subjected to ultrasound and electrostatic field treatment, centrifuged to remove excess sol, gradient dried, and annealed to obtain the product.

3. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 1, characterized in that: The ultrasonic parameters of step A2 are: ultrasonic frequency of 30-50kHz, ultrasonic power of 150-250W, and ultrasonic treatment for 8-12min; the electrostatic field treatment refers to applying a 9-11kV / m DC electric field for 14-16min; the gradient drying refers to pre-drying in an 80°C oven for 0.8-1.2h, and then drying in a 120°C oven for 25-35min; the annealing refers to heating to 300-320°C at 5°C / min under a nitrogen atmosphere and keeping warm for 1-2h.

4. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 2, characterized in that: The alumina fiber in step A2 needs to be pre-treated, and the pre-treatment includes the following steps: Step B1: Under a nitrogen atmosphere, heat the alumina fiber to 440-460°C, keep it warm for 2-3 hours, cool it to room temperature, and then immerse it in a coupling agent-acetone solution. Set the ultrasonic frequency to 30-50kHz and the ultrasonic power to 300-400W for 20-40 minutes, and dry it at 80°C.

5. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 4, characterized in that: The heating rate in step B1 is 10-12° C. / min; the content of the coupling agent in the coupling agent-acetone solution is 4-6 wt %; and the coupling agent is an aluminate coupling agent.

6. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 2, characterized in that: The preparation method of the electromagnetic shielding microspheres described in step A2 comprises the following steps: Step C1, immersing the glass fiber in nickel solution, placing it in a constant temperature water bath at 80°C, stirring at a speed of 10-50 rpm for 30-40 minutes, taking it out, washing it, and drying it at 60°C to obtain nickel-loaded fiber; Step C2, loading aluminum on the nickel-loaded fiber to obtain aluminum-nickel-loaded fiber; Step C3: immersing the aluminum-nickel loaded fibers in molten iron, subjecting them to microwave treatment under a nitrogen atmosphere, and then rinsing them alternately with anhydrous ethanol and deionized water three times, followed by annealing to obtain electromagnetic shielding microspheres.

7. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 6, characterized in that: The nickel solution in step C1 is prepared by mixing nickel sulfamate, sodium citrate, sodium saccharin, sodium borohydride, and deionized water in a mass ratio of 0.4-0.5:0.2-0.3:0.05-0.06:0.008-0.012:93.5-95.5, and triethanolamine is added dropwise to adjust the pH to 8.4-8.6; the nickel layer thickness of the nickel-loaded fiber is 0.8 μm.

8. The outer sheath material of a cable containing alumina fiber and having electromagnetic shielding function according to claim 6, characterized in that: The aluminum load in step C2 refers to the arc spraying aluminum layer. The parameters of the arc spraying equipment are: voltage of 30V, current of 200A, spraying distance of 150mm, and spraying thickness of 1.2μm.

9. The outer sheath material of a cable containing alumina fiber with electromagnetic shielding according to claim 6, characterized in that: The iron liquid in step C3 is obtained by mixing ferrous sulfate, urea, sodium citrate, hydrogen peroxide, and deionized water in a mass ratio of 8.34-8.38:6-6.2:0.8-1.2:1.13-1.17:91-92; the parameters of the microwave treatment are: power 350-450W, temperature 74-76°C, and time 28-32min; the annealing treatment refers to annealing at 245-255°C under a nitrogen atmosphere for 0.8-1.2h.

10. The outer sheath material of a cable containing alumina fiber and having electromagnetic shielding function according to any one of claims 1 to 9, characterized in that: The preparation method of the cable outer sheath material comprises the following steps: Step D1: preheat the linear low-density polyethylene to 85°C to soften it, add electromagnetic shielding microspheres wrapped with alumina fibers, ethylene-vinyl acetate copolymer, aluminate coupling agent, and antioxidant, mix at a speed of 300-400 rpm for 30-40 minutes, extrude and granulate to obtain the cable outer sheath material.

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