Heat-resistant cable material and preparation method thereof

Abstract

The invention relates to the technical field of cable materials, and provides a heat-resistant cable material and a preparation method thereof, and the heat-resistant cable material comprises the following components by mass: 40-60 parts of matrix resin; 10-20 parts of a modified graphene reinforcing filler; 5-15 parts of a filling agent; 2-8 parts of a phosphorus-nitrogen flame retardant; 0.5 to 2 parts of an antioxidant; 0.1 to 1 part of a lubricant; the modification process of the modified graphene reinforced filler comprises the following steps: preparing graphene oxide powder from natural graphite through an oxidation method, performing high-temperature reduction on the graphene oxide powder in an inert atmosphere to obtain few-layer graphene powder, mixing the few-layer graphene powder and a surface modifier in a solvent, and performing ultrasonic dispersion to obtain the modified graphene reinforced filler. The heat-resistant cable material is obtained by oxidizing and reducing natural graphite at a high temperature, modifying the graphene reinforcing filler and then mixing with other components, so that the comprehensive performance of the heat-resistant cable material is improved, and the heat-resistant cable material particularly shows excellent heat stability and flame retardance in a high-temperature environment.

Description

Technical Field

[0001] This application relates to the technical field of cable materials, and particularly to a heat-resistant cable material and a preparation method thereof. Background Art

[0002] As a core component for power transmission and communication, cables are widely used in fields such as energy, transportation, communication, and construction. With the continuous progress of technology and the acceleration of the industrialization process, modern cable materials not only need to meet basic mechanical strength and wear resistance, but also need to have good heat resistance, flame retardancy, and anti-aging performance to meet the usage requirements in extreme environments. Especially in high-temperature, high-humidity, and strongly corrosive environments, the performance of cable materials is particularly important.

[0003] In the prior art, heat-resistant cable materials are usually prepared by physically blending a matrix polymer with high-temperature resistant fillers, flame retardants, and antioxidants, or by chemical cross-linking to form a three-dimensional network structure to improve the heat resistance of the materials.

[0004] For the above technical solutions, although physically blending the matrix polymer with high-temperature resistant fillers, flame retardants, and antioxidants can achieve a certain degree of improvement in heat resistance, in practical applications, the dispersion in the matrix resin is poor, which easily causes non-uniformity of material properties. Especially in a long-term high-temperature environment, the thermal stability and anti-aging performance of the materials are difficult to meet the application requirements of high-end cables. Summary of the Invention

[0005] In order to improve the problem that in practical applications, the dispersion in the matrix resin is poor, which easily causes non-uniformity of material properties, and especially in a long-term high-temperature environment, the thermal stability and anti-aging performance of the materials are difficult to meet the application requirements of high-end cables, this application provides a heat-resistant cable material and a preparation method thereof.

[0006] The present invention provides a heat-resistant cable material, which comprises the following components in parts by mass: 40 - 60 parts of matrix resin; 10 - 20 parts of modified graphene reinforcing filler; 5 - 15 parts of filler; 2 - 8 parts of phosphorus-nitrogen based flame retardant; 0.5 - 2 parts of antioxidant; 0.1 - 1 part of lubricant; the modification process of the modified graphene reinforcing filler is as follows: preparing graphene oxide powder from natural graphite by an oxidation method, reducing the graphene oxide powder at high temperature in an inert atmosphere to obtain few-layer graphene powder, and mixing the few-layer graphene powder with a surface modifier in a solvent and ultrasonically dispersing to obtain the modified graphene reinforcing filler.

[0007] As a preferred embodiment, the step of preparing graphene oxide powder from natural graphite by the oxidation method includes: mixing natural graphite with concentrated sulfuric acid and concentrated nitric acid in a preset mass ratio, stirring and reacting for 4 hours to form an intercalation compound; adding potassium permanganate with a mass ratio of 1:1 to natural graphite to the intercalation compound, controlling the reaction temperature below 20°C, stirring for 2 hours to obtain a reaction solution, adding deionized water three times the total volume of the reaction solution for dilution and stirring for 30 minutes; adding a hydrogen peroxide solution with a volume of 10% of the total volume of the reaction solution for reaction to obtain a graphene oxide suspension, and after centrifuging, washing and drying the graphene oxide suspension, graphene oxide powder is obtained.

[0008] As a preferred embodiment, the step of high-temperature reducing graphene oxide powder in an inert atmosphere to obtain few-layer graphene powder includes: placing the graphene oxide powder in a quartz boat of a tube furnace and heating it under the protection of nitrogen or argon to obtain few-layer graphene powder.

[0009] As a preferred embodiment, the step of mixing few-layer graphene powder with a surface modifier in a solvent and ultrasonically dispersing it to obtain a modified graphene reinforcing filler includes: adding few-layer graphene powder to water, preparing a suspension, adding a surface modifier, stirring evenly to obtain a graphene solution; treating the graphene solution under ultrasonic conditions for 3 hours to obtain a loaded graphene solution, and after filtering, washing and drying the loaded graphene solution, a modified graphene reinforcing filler is obtained.

[0010] As a preferred embodiment, the matrix resin is selected from one of polyvinylidene fluoride, polytetrafluoroethylene, polyimide, and polyphenylene sulfide.

[0011] As a preferred embodiment, the filler is selected from one of silicate microspheres, mica powder, talc powder, and alumina fine powder.

[0012] As a preferred embodiment, the phosphorus-nitrogen based flame retardant is selected from one of melamine phosphate, polyphosphoric amide, red phosphorus, and pentaerythritol phosphate ester.

[0013] As a preferred embodiment, the antioxidant is selected from one or at least two combinations of phosphite antioxidants, antioxidant 1010, and antioxidant 1076.

[0014] As a preferred embodiment, the lubricant is selected from one or at least two combinations of zinc stearate, polyethylene wax, and ethylene glycol distearate.

[0015] The present application also provides a preparation method of a heat-resistant cable material. The preparation method includes: adding a matrix resin, a modified graphene reinforcing filler, a filler, a phosphorus-nitrogen based flame retardant, an antioxidant and a lubricant into a high-speed mixer, mixing for 10 - 30 minutes to obtain a uniform mixture; feeding the uniform mixture into a twin-screw extruder, melt-extruding under the conditions of a temperature of 190 - 220 °C and a rotation speed of 60 - 120 r / min to obtain a molten material, cooling the molten material through a water cooling device, and pelletizing to obtain the heat-resistant cable material.

[0016] Compared with the prior art, the present application has the following beneficial effects: strong thermal stability and good flame retardancy. By oxidizing natural graphite and performing high-temperature reduction, a modified graphene reinforcing filler with high thermal stability and high dispersibility is prepared. The matrix resin, the modified graphene reinforcing filler, the filler, the phosphorus-nitrogen based flame retardant, the antioxidant and the lubricant are mixed in a predetermined ratio, and are melt-blended under high-temperature conditions through a twin-screw extruder. The molten material is cooled and pelletized to obtain a heat-resistant cable material with high thermal stability, high flame retardancy and excellent mechanical properties, significantly improving the comprehensive performance of the heat-resistant cable material, especially showing excellent thermal stability and flame retardancy in a high-temperature environment. Specific embodiments

[0017] The technical solution of the present invention will be further described below through specific examples. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0018] Example 1: This example provides a heat-resistant cable material, including the following components in parts by mass: Polyvinylidene fluoride: 50 parts; Modified graphene reinforcing filler: 15 parts; Silicate microspheres: 10 parts; Melamine phosphate: 5 parts; Antioxidant 1010: 1 part; Zinc stearate: 0.5 part.

[0019] Preparation method: The preparation of the modified graphene reinforced filler includes: mixing natural graphite with concentrated sulfuric acid and concentrated nitric acid in a mass ratio of 1:9:3, stirring and reacting for 2 - 4 hours to form an intercalation compound; under ice bath conditions, adding potassium permanganate with a mass ratio of 1:1 to natural graphite to the intercalation compound, controlling the reaction temperature below 20 °C, stirring for 1 - 2 hours to obtain a reaction solution, adding deionized water with a volume 2 - 3 times that of the total volume of the reaction solution and stirring for 30 minutes, then adding 5 - 10% of the total volume of the reaction solution of 30 wt% hydrogen peroxide solution for reaction until the color of the reaction solution changes from dark brown to light yellow, and then removing the ice bath conditions to obtain a graphene oxide suspension.

[0020] Centrifuge the graphene oxide suspension at a speed of 5000 - 8000 rpm for 20 minutes to obtain precipitated graphene oxide, and wash the centrifuged graphene oxide precipitate with deionized water and ethanol multiple times until the washing liquid is neutral to obtain the washed graphene oxide precipitate; finally, dry the washed graphene oxide precipitate in a vacuum drying oven at 50 - 60 °C to obtain graphene oxide powder.

[0021] Place the graphene oxide powder in a quartz boat of a tube furnace, heat it to 800 °C at a heating rate of 10 °C / min under the protection of nitrogen or argon, keep it at 800 °C for 1 hour, then turn off the heating device, introduce nitrogen or argon, and cool it naturally to room temperature to obtain few-layer graphene powder.

[0022] Add the few-layer graphene powder to water, prepare a suspension according to a mass ratio of water to few-layer graphene powder of 100:1, and add a surface modifier, stir evenly to obtain a graphene solution; wherein, the mass ratio of the surface modifier to the suspension is 1:50, and the surface modifier is selected from one of silane coupling agents (such as KH-550), titanate coupling agents, and phenolic resins.

[0023] Under ultrasonic conditions, treat the graphene solution for 1 - 3 hours to uniformly load the surface modifier on the surface of graphene to obtain a loaded graphene solution, filter the loaded graphene solution through a 0.22 μm filter membrane to obtain a filtered graphene precipitate, wash the filtered graphene precipitate with deionized water 3 - 5 times until the washing liquid is neutral to obtain the washed graphene precipitate, and dry the washed graphene precipitate in a vacuum drying oven at 60 °C to obtain the modified graphene reinforced filler.

[0024] Raw material mixing: Add polyvinylidene fluoride, modified graphene reinforced filler, silicate microspheres, melamine phosphate, antioxidant 1010, and zinc stearate to a high-speed mixer according to the formula ratio and mix for 20 minutes to obtain a uniform mixture.

[0025] Melting blending and forming: The mixture is fed into a twin-screw extruder and melt-extruded at 200 °C and a rotational speed of 80 r / min, and then pelletized after water cooling to obtain the heat-resistant cable material.

[0026] The test properties of the heat-resistant cable material include: Tensile strength (MPa): According to the standard of GB / T 1040-2006.

[0027] Elongation at break (%): According to the standard of GB / T 1040-2006.

[0028] Thermal stability (°C): Measured by thermogravimetric analysis (TGA), and the temperature of 5% thermal weight loss is recorded.

[0029] Flame retardancy (LOI%): The limiting oxygen index (LOI) is tested according to the standard of GB / T 2406.2-2009.

[0030] Anti-aging performance: After aging the sample in hot air at 100 °C for 168 hours, the retention rates of tensile strength and elongation at break are tested.

[0031] The test results of the material properties of this example: The tensile strength is 25.5 MPa, the elongation at break is 180%, the thermal stability is 340 °C, the flame retardancy is 32.5 LOI%, and the anti-aging performance is 85%.

[0032] Example 2: This example provides a heat-resistant cable material, including the following components in parts by mass: Polytetrafluoroethylene: 60 parts; Modified graphene-reinforced filler: 12 parts; Mica powder: 8 parts; Red phosphorus: 6 parts; Phosphite antioxidant: 1.5 parts; Polyethylene wax: 0.8 parts.

[0033] Preparation method: Preparation of the modified graphene-reinforced filler: The steps are the same as those in Example 1.

[0034] Raw material mixing: Add polytetrafluoroethylene, modified graphene-reinforced filler, mica powder, red phosphorus, phosphite antioxidant and polyethylene wax into a high-speed mixer according to the formula ratio, and mix for 25 minutes to obtain a uniform mixture.

[0035] Melting blending and forming: The mixture is fed into a twin-screw extruder and melt-extruded at 210 °C and a rotational speed of 100 r / min, and then pelletized after water cooling to obtain the heat-resistant cable material.

[0036] Material property test results of this example: Tensile strength is 27.5 MPa, elongation at break is 175%, thermal stability is 345 °C, flame retardancy is 33.0 LOI%, and anti-aging property is 87%.

[0037] Example 3: This example provides a heat-resistant cable material, including the following components in parts by mass: Polyimide: 55 parts; Modified graphene reinforced filler: 18 parts; Talc powder: 10 parts; Pentaerythritol phosphate: 4 parts; Mixed antioxidant (a 1:1 mixture of antioxidant 1010 and phosphite antioxidant): 1.8 parts; Ethylene glycol distearate: 0.3 parts.

[0038] Preparation method: Preparation of modified graphene reinforced filler: The steps are the same as those in Example 1.

[0039] Raw material mixing: Add polyimide, modified graphene reinforced filler, talc powder, pentaerythritol phosphate, mixed antioxidant and ethylene glycol distearate into a high-speed mixer according to the formula ratio, and mix for 15 minutes to obtain a uniform mixture.

[0040] Melt blending and molding: Feed the mixture into a twin-screw extruder, melt extrude at 200 °C and a rotation speed of 70 r / min, and pelletize after water cooling to obtain the heat-resistant cable material.

[0041] Material property test results of this example: Tensile strength is 26.8 MPa, elongation at break is 185%, thermal stability is 350 °C, flame retardancy is 32.8 LOI%, and anti-aging property is 88%.

[0042] Example 4: This example provides a heat-resistant cable material, including the following components in parts by mass: Polyphenylene sulfide: 45 parts; Modified graphene reinforced filler: 20 parts; Aluminum oxide fine powder: 12 parts; Ammonium polyphosphate: 7 parts; Antioxidant 1076: 2 parts; Mixed lubricant (a 2:1 mixture of zinc stearate and polyethylene wax): 1 part.

[0043] Preparation method: Preparation of modified graphene reinforced filler: The steps are the same as those in Example 1.

[0044] Raw material mixing: Add polyphenylene sulfide, modified graphene reinforcing filler, alumina micropowder, ammonium polyphosphate, antioxidant 1076 and mixed lubricant into a high-speed mixer according to the formula ratio, and mix for 30 minutes to obtain a uniform mixture.

[0045] Melting blending and molding: Feed the mixture into a twin-screw extruder, melt and extrude it at 220 °C and a rotational speed of 90 r / min, and pelletize it after water cooling to obtain heat-resistant cable material.

[0046] Material property test results of this example: Tensile strength is 28.5 MPa, elongation at break is 170%, thermal stability is 355 °C, flame retardancy is 34.5 LOI%, and anti-aging property is 89%.

[0047] Comparison 1: The dosage of modified graphene reinforcing filler is 0, and other components and their dosages remain the same as in Example 1.

[0048] Material property test results: Tensile strength is 15.0 MPa, elongation at break is 100%, thermal stability is 260 °C, flame retardancy is 20.0 LOI%, and anti-aging property is 55%.

[0049] Comparison 2: The matrix resin is selected as polyethylene (PE), the modified graphene reinforcing filler is not used, and other components and their dosages are the same as in Example 1.

[0050] Material property test results: Tensile strength is 18.0 MPa, elongation at break is 120%, thermal stability is 280 °C, flame retardancy is 25.0 LOI%, and anti-aging property is 60%.

[0051] Comparison 3: The dosage of phosphorus-nitrogen based flame retardant is 0, and other components and their dosages remain the same as in Example 2.

[0052] Material property test results: Tensile strength is 20.0 MPa, elongation at break is 140%, thermal stability is 300 °C, flame retardancy is 28.0 LOI%, and anti-aging property is 65%.

[0053] Comparison 4: The dosage of filler is 0, and other components and their dosages remain the same as in Example 3.

[0054] Material property test results: Tensile strength is 21.5 MPa, elongation at break is 150%, thermal stability is 310 °C, flame retardancy is 30.0 LOI%, and anti-aging property is 70%.

[0055] Comparison 5: The dosage of antioxidant is 0, and other components and their dosages remain the same as in Example 4.

[0056] Test results of material properties: Tensile strength is 22.0 MPa, elongation at break is 160%, thermal stability is 315 °C, flame retardancy is 31.0 LOI%, and anti-aging performance is 75%.

[0057] Comparison 6: The amount of lubricant is 0, and the other components and their amounts remain the same as in Example 3.

[0058] Test results of material properties: Tensile strength is 23.0 MPa, elongation at break is 165%, thermal stability is 320 °C, flame retardancy is 31.5 LOI%, and anti-aging performance is 78%.

[0059] The performance of the heat-resistant cable materials of Examples 1 to 4 and Comparative Examples 1 to 6 was tested, and the results are shown in Table 1 below: Table 1: Based on the result analysis of Table 1: Tensile strength and elongation at break: In Examples 1 to 4, due to the use of modified graphene reinforcing fillers and optimized matrix resins, they showed relatively high tensile strength and good ductility. In the control group, due to the non-use of key materials or insufficient component ratios, the tensile strength and ductility were significantly reduced.

[0060] Thermal stability: In Examples 1 to 4, the thermal stability was significantly improved. The modified graphene reinforcing filler prepared by high-temperature reduction at 800 °C played an excellent thermal barrier effect in the matrix resin. In Comparatives 1 to 6, the non-use of modified graphene or flame retardants led to earlier degradation of the material at high temperatures.

[0061] Flame retardancy (LOI%): Examples 1 to 4 all reached an oxygen index of more than 32%, indicating that the materials had good flame retardancy. When the phosphorus-nitrogen-based flame retardant was not added in Comparatives 1 to 6, the flame retardancy decreased significantly, only about 20%.

[0062] Anti-aging performance: In Examples 1 to 4, the anti-aging performance was excellent. Especially in the aging environment of 100 °C, the strength retention rate reached more than 85%, indicating that the synergistic effect of antioxidants and modified graphene effectively slowed down the oxidative degradation of the material. In Comparatives 1 to 6, the non-addition of antioxidants or lubricants led to a significant decrease in performance after aging.

[0063] Conclusion: The formulations of Examples 1 to 4 considered mechanical properties, flame retardancy, and heat resistance stability, and achieved significant synergistic effects by using modified graphene reinforcing fillers. In the comparison of the performance data between Examples 1 to 4 and Comparatives 1 to 6, the superiority of Examples 1 to 4 was verified, and it could meet the high-performance requirements of heat-resistant cable materials.

[0064] The applicant declares that the above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A heat-resistant cable material, characterized in that: The composition comprises the following components in parts by weight: 40-60 parts of base resin; 10-20 parts of modified graphene reinforced filler; 5-15 parts of filler; 2-8 parts of phosphorus-nitrogen flame retardant; 0.5-2 parts of antioxidant; Lubricant 0.1-1 part; The modification process of the modified graphene reinforced filler is as follows: preparing graphene oxide powder from natural graphite by an oxidation method, reducing the graphene oxide powder at high temperature in an inert atmosphere to obtain few-layer graphene powder, mixing the few-layer graphene powder with a surface modifier in a solvent, and ultrasonically dispersing the mixture to obtain the modified graphene reinforced filler.

2. The heat-resistant cable material according to claim 1, characterized in that: The step of preparing graphene oxide powder from natural graphite by oxidation method comprises: Mixing natural graphite with concentrated sulfuric acid and concentrated nitric acid in a preset mass ratio, stirring and reacting for 4 hours to form an intercalation compound; Add potassium permanganate in a mass ratio of 1:1 to natural graphite to the intercalation compound, control the reaction temperature below 20°C, stir for 2 hours to obtain a reaction solution, add deionized water 3 times the total volume of the reaction solution to dilute and stir for 30 minutes; A hydrogen peroxide solution in an amount of 10% of the total volume of the reaction solution was added to react to obtain a graphene oxide suspension. The graphene oxide suspension was centrifuged, washed and dried to obtain graphene oxide powder.

3. The heat-resistant cable material according to claim 1, characterized in that: The step of reducing the graphene oxide powder at high temperature in an inert atmosphere to obtain the few-layer graphene powder comprises: The graphene oxide powder is placed in a quartz boat of a tube furnace and heated under the protection of nitrogen or argon to obtain a few-layer graphene powder.

4. The heat-resistant cable material according to claim 1, characterized in that: The step of mixing the few-layer graphene powder and the surface modifier in a solvent and ultrasonically dispersing the mixture to obtain the modified graphene reinforced filler comprises: The few-layer graphene powder is added into water to prepare a suspension, and then a surface modifier is added and stirred to obtain a graphene solution; The graphene solution is treated under ultrasonic conditions for 3 hours to obtain a loaded graphene solution, and the loaded graphene solution is filtered, washed and dried to obtain a modified graphene reinforced filler.

5. The heat-resistant cable material according to claim 1, characterized in that: The matrix resin is selected from one of polyvinylidene fluoride, polytetrafluoroethylene, polyimide and polyphenylene sulfide.

6. The heat-resistant cable material according to claim 1, characterized in that: The filler is selected from one of silicate microspheres, mica powder, talcum powder and alumina micropowder.

7. The heat-resistant cable material according to claim 1, characterized in that: The phosphorus-nitrogen flame retardant is selected from one of melamine phosphate, polyphosphate amine, red phosphorus, and pentaerythritol phosphate.

8. The heat-resistant cable material according to claim 1, characterized in that: The antioxidant is selected from one of phosphite antioxidants, antioxidant 1010, and antioxidant 1076, or a combination of at least two of them.

9. The heat-resistant cable material according to claim 1, characterized in that: The lubricant is selected from one or a combination of at least two of zinc stearate, polyethylene wax, and ethylene glycol distearate.

10. The method for preparing a heat-resistant cable material according to any one of claims 1 to 9, characterized in that: The preparation method comprises: Adding the base resin, modified graphene reinforced filler, filler, phosphorus nitrogen flame retardant, antioxidant and lubricant into a high-speed mixer and mixing for 10-30 minutes to obtain a uniform mixture; The uniform mixture is fed into a twin-screw extruder, and melt-extruded at a temperature of 190-220° C. and a rotation speed of 60-120 r / min to obtain a molten material. The molten material is cooled by a water cooling device and pelletized to obtain a heat-resistant cable material.

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