Insulated power cable

Abstract

The invention relates to the technical field of power cables, and provides an insulated power cable which sequentially comprises a conductor layer, an insulating layer, a shielding layer and an outer sheath layer from inside to outside. And the outer sheath layer is prepared from the following raw materials in parts by weight: 83-95 parts of polyvinyl chloride resin, 20-30 parts of polyethylene resin, 8-16 parts of modified talcum powder, 4-12 parts of a functional aid and 3-6 parts of a lubricant. Wherein the tensile resistance, extrusion resistance and bending resistance of the outer sheath layer are remarkably enhanced by the'lamellar network 'structure of the modified talcum powder, and the cracking risk of the cable is reduced; wherein the functional additive can enhance the high temperature resistance, water resistance and corrosion resistance of the outer sheath layer and improve the environmental adaptability of the cable; in conclusion, the cable prepared by the invention has excellent mechanical strength and environmental adaptability, is suitable for severe environments such as damp, acid-base, salt mist and the like, and has important application value in the technical field of power cables.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power cable, in particular, to an insulated power cable. BACKGROUND

[0002] In the field of modern power transmission, as an indispensable key component in the power system, the performance of the insulated power cable directly affects the safety, stability and efficiency of power transmission. With the continuous expansion of the power grid scale, the continuous growth of power load and the increasing diversification of application scenarios, the performance requirements for the insulated power cable are becoming increasingly stringent. The traditional insulated power cable gradually exposes many problems that cannot meet the current demand in the actual use process.

[0003] Because the outer sheath layer of the cable directly contacts with the external environment, the outer sheath layer has a crucial influence on the overall performance of the cable. The traditional insulated cable outer sheath layer material mainly adopts cross-linked polyethylene (XLPE), ethylene-propylene rubber (EPR) or polyvinyl chloride (PVC), etc. These materials have certain electrical insulation performance and mechanical properties, but as people's demand continues to improve, higher requirements are put forward for the environmental adaptability of the cable. For example, laying the cable in the underground cable trench, coastal areas or underwater humid environment poses a severe challenge to the waterproof performance of the cable. The penetration of water into the insulation layer will increase the dielectric loss, aggravate the partial discharge and even cause water treeing, ultimately leading to insulation breakdown. In addition, in industrial areas, chemical plants or coastal salt spray environments, the cable may be exposed to corrosive media such as acid, alkali, oil stains or salt. The ordinary PVC outer sheath is prone to hardening and cracking under chemical corrosion. Finally, the cable may be subjected to mechanical stress such as stretching, extrusion, bending and vibration during laying and operation. For example, mining cables need to be moved frequently, submarine cables need to withstand water flow impact, and urban underground cables may be damaged by external forces due to construction or geological activities. The outer sheath layer of the traditional cable may appear micro-cracks under long-term mechanical stress, leading to partial discharge or insulation failure. Therefore, environmental adaptability and mechanical strength are one of the core challenges in the development of insulated power cable technology, and there is an urgent need to invent an insulated power cable with strong environmental adaptability and high mechanical strength to meet the higher demands in the field of power cable technology. SUMMARY

[0004] The present application provides an insulated power cable, which solves the problem of poor environmental adaptability and insufficient mechanical strength of the cable in the related art.

[0005] The technical scheme of the present application is as follows: The present application provides an insulated power cable, which solves the problem of poor environmental adaptability and insufficient mechanical strength of the cable in the related art.

[0006] As a further technical scheme, the material of the conductor layer is oxygen-free copper.

[0007] As a further technical solution, the material of the insulation layer is polyvinyl chloride.

[0008] As a further technical solution, the material of the shielding layer is a tin-plated copper strip.

[0009] As a further technical solution, the material of the outer sheath layer includes the following raw materials in parts by weight: 83-95 parts of polyvinyl chloride resin, 20-30 parts of polyethylene resin, 8-16 parts of modified talc powder, 4-12 parts of functional additives, and 3-6 parts of lubricant.

[0010] As a further technical solution, the lubricant is one of stearic acid, glycerol monostearate, polyethylene wax, and oleic acid amide.

[0011] As a further technical solution, the modified talc powder is prepared by the following steps: Step A1, place the talc powder in an electric heating air drying oven and dry at 100-120℃ for 2-4h to remove the surface adsorbed water, obtaining dry talc powder; Step A2, dissolve stearic acid in anhydrous ethanol, ultrasonic treatment until the solution is transparent, then add the dry talc powder obtained in step A1, and drop the dilute hydrochloric acid solution to adjust the pH of the reaction system to 4-5, stir at 70℃ for 2h, after the reaction is completed, centrifuge, wash 3 times with ethanol / water (1:1) mixture, and finally vacuum dry in an oven at 80℃ for 6h, obtaining modified talc powder.

[0012] As a further technical solution, the mass ratio of talc powder to stearic acid is 100:3-9.

[0013] The particles of talc powder are layered flakes, and this structure makes it easy to form a "lamellar network" of parallel arrangement in the polymer material. This structure can make the cable less prone to sheath cracking, insulation layer damage, and other problems in complex laying environment, improve the mechanical properties of the cable, and through stearic acid modification, improve the compatibility of talc powder and polyvinyl chloride resin, making talc powder more easily dispersed in the polyvinyl chloride resin matrix, further improving the beneficial effect of talc powder on the mechanical properties of the cable.

[0014] As a further technical solution, the functional additive is prepared by the following steps: Step B1, in a magnetic stirring reaction kettle with a condenser, add pentafluoroaniline, 3-mercaptopropionic acid and anhydrous dichloromethane, after nitrogen is introduced, ice bath cooling to 0-5℃, slowly drop N,N-diisopropyl ethylamine, after magnetic stirring is uniform, add 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide, remove the ice bath, warm up to 40℃ for 12h, after reaction is completed, add saturated NaHCO3 solution to quench, separate, the organic phase is washed with citric acid and saturated brine, dry with anhydrous sodium sulfate, remove dichloromethane by rotary evaporation, finally silica gel column chromatography (petroleum ether / ethyl acetate = 3 / 1→1 / 1 gradient elution), get amide product; As a further technical solution, the ratio of the amount of pentafluoroaniline, 3-mercaptopropionic acid, anhydrous dichloromethane, N,N-diisopropyl ethylamine, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride, N-hydroxysuccinimide in step B1 is 18.1g:10.6g:200mL:25.8:22.3g:11.5g.

[0015] The reaction principle of step B1 is that pentafluoroaniline and 3-mercaptopropionic acid undergo amide reaction under the catalysis of N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride, N,N-diisopropyl ethylamine can prevent the protonation of mercapto group, and the reaction formula is as follows:

[0016] Step B2, in a magnetic stirring reaction kettle with a condenser, add amide product, azobisisobutyronitrile (AIBN) and anhydrous toluene, after magnetic stirring is uniform, introduce nitrogen, slowly drop tetramethyltetraethenylcyclotetrasiloxane, after drop is completed, the device is warmed to 70℃, react for 8h, the reaction process is constantly stirred, after reaction is completed, cool to room temperature, remove part of the solvent by distillation under reduced pressure, finally silica gel column chromatography (petroleum ether / ethyl acetate = 5 / 1→1 / 1 gradient elution), get functional assistant; As a further technical solution, the ratio of the amount of amide product, azobisisobutyronitrile, anhydrous dichloromethane, anhydrous toluene, tetramethyltetraethenylcyclotetrasiloxane in step B2 is 111.7g:1.6g:200mL:34.4g.

[0017] The reaction principle of step B2 is that amide product and tetramethyltetraethenylcyclotetrasiloxane undergo click reaction of mercapto-alkene under the catalysis of AIBN, adjust the molar ratio to be close to 4:1 (and amide product is slightly excessive), so that the reaction is sufficient, and the reaction formula is as follows:

[0018] The functional aid prepared by the application is centered on cyclic siloxane, and is connected with multiple C-F bonds, wherein the cyclic siloxane contains multiple siloxane bonds (Si-O), the siloxane bond has high bond energy and good stability, is difficult to be destroyed by strong acid, strong base or oxidant, and shows inertness to water, salt solution and most chemical reagents, and the introduction of phenyl can also improve the high-temperature resistance of the aid; the multiple C-F bond structures contained in the functional aid also have high bond energy, are difficult to be destroyed by common chemical reagents (such as strong acid, strong base and strong oxidant), and the C-F bond can effectively shield the carbon atom from the attack of electrophilic reagents; at the same time, the fluorine atom has a small radius and has three pairs of lone pair electrons on the outer layer, which are arranged closely around the carbon chain to form a spiral shielding layer, physically blocking other molecules from approaching the C-C main chain and hindering the occurrence of chemical reactions; when the fluorine atom is added as one of the raw materials to the outer sheath layer, the corrosion resistance, waterproofness and heat resistance of the PVC matrix can be greatly improved, the environmental adaptability of the cable is improved, and the cable can still work normally in extreme environments.

[0019] The working principle and beneficial effects of the application are as follows: 1. The modified talcum powder is added to the outer sheath layer, and the "sheet network" structure of the modified talcum powder significantly enhances the tensile resistance, extrusion resistance and bending resistance of the outer sheath layer, thereby reducing the risk of cable cracking. 2. A functional aid containing multiple functional groups is designed and synthesized, which significantly enhances the high-temperature resistance, waterproofness and corrosion resistance of the outer sheath layer, improves the environmental adaptability of the cable, and the synthesis steps of the functional aid are clear and the reaction conditions are controllable, which is suitable for industrial production. In summary, the cable prepared by the application has excellent mechanical strength and environmental adaptability, is suitable for use in humid, acid-base, salt mist and other harsh environments, and has important application value in the field of power cable technology. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0021] Embodiment 1 Preparation of modified talcum powder: Step A1, 100g of talcum powder is placed in an electric heating air drying oven and dried at 100℃ for 2h to remove the surface adsorbed water, and dry talcum powder is obtained; Step A2, 3g stearic acid was dissolved in 300mL anhydrous ethanol, ultrasonic treatment until the solution was transparent, then the dry talc powder obtained in step A1 was added, and the pH of the reaction system was adjusted to 4 by adding dilute hydrochloric acid solution (mass fraction 12%), constant temperature stirring at 70℃ for 2h, after the reaction was completed, centrifugation, washing with ethanol / water (1:1) mixture for 3 times, and finally vacuum drying in an oven at 80℃ for 6h to obtain the modified talc powder.

[0022] Example 2 Preparation of modified talc powder: Step A1, 100g talc powder was placed in an electric heating air oven, dried at 120℃ for 4h to remove the surface adsorbed water, and dry talc powder was obtained; Step A2, 9g stearic acid was dissolved in 300mL anhydrous ethanol, ultrasonic treatment until the solution was transparent, then the dry talc powder obtained in step A1 was added, and the pH of the reaction system was adjusted to 5 by adding dilute hydrochloric acid solution (mass fraction 12%), constant temperature stirring at 70℃ for 2h, after the reaction was completed, centrifugation, washing with ethanol / water (1:1) mixture for 3 times, and finally vacuum drying in an oven at 80℃ for 6h to obtain the modified talc powder.

[0023] Example 3 Preparation of functional adjuvant: Step B1, 72.4g pentafluoroaniline, 42.4g 3-mercaptopropionic acid and 800mL anhydrous dichloromethane were added to a magnetic stirring reaction kettle with a condenser, after nitrogen was introduced, the ice bath was cooled to 0℃, 103.2g N,N-diisopropylethylamine was slowly added, after magnetic stirring, 89.2g 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 46.0g N-hydroxysuccinimide were added, the ice bath was removed, and the temperature was raised to 40℃ for reaction for 12h, after the reaction was completed, saturated NaHCO3 solution was added to quench, liquid-liquid separation was performed, the organic phase was washed with citric acid and saturated brine, anhydrous sodium sulfate was used for drying, dichloromethane was removed by rotary evaporation, and finally silica gel column chromatography (petroleum ether / ethyl acetate=3 / 1→1 / 1 gradient elution) was performed to obtain the amidation product; Step B2, 111.7g of the amidation product, 1.6g azobisisobutyronitrile and 200mL anhydrous toluene were added to a magnetic stirring reaction kettle with a condenser, after magnetic stirring, nitrogen was introduced, 34.4g tetramethyltetraethenylcyclotetrasiloxane was slowly added, after the addition was completed, the device was heated to 70℃, and reaction was performed for 8h, the reaction was continuously stirred during the process, after the reaction was completed, the temperature was cooled to room temperature, part of the solvent was removed by reduced pressure distillation, and finally silica gel column chromatography (petroleum ether / ethyl acetate=5 / 1→1 / 1 gradient elution) was performed to obtain the functional adjuvant.

[0024] Example 4 Preparation of material for outer sheath layer: The 83 g of polyvinyl chloride resin, 20 g of polyethylene resin were placed in a vacuum oven and dried at 80 °C for 2 h, then 8 g of modified talc powder prepared in Example 1, 4 g of functional additive prepared in Example 3 and 3 g of glycerol monostearate were added into the extruder, after melt blending, extruded to obtain the material of the outer sheath layer.

[0025] Example 5 Preparation of the material of the outer sheath layer: The 89 g of polyvinyl chloride resin, 25 g of polyethylene resin were placed in a vacuum oven and dried at 80 °C for 2 h, then 12 g of modified talc powder prepared in Example 2, 8 g of functional additive prepared in Example 3 and 4 g of polyethylene wax were added into the extruder, after melt blending, extruded to obtain the material of the outer sheath layer.

[0026] Example 6 Preparation of the material of the outer sheath layer: The 95 g of polyvinyl chloride resin, 30 g of polyethylene resin were placed in a vacuum oven and dried at 80 °C for 2 h, then 16 g of modified talc powder prepared in Example 2, 12 g of functional additive prepared in Example 3 and 6 g of oleic acid amide were added into the extruder, after melt blending, extruded to obtain the material of the outer sheath layer.

[0027] Example 7 The oxygen-free copper was drawn into copper wire using a wire drawing machine, and then twisted by a stranding machine to form a conductor layer; the polyvinyl chloride was extruded by an extruder to coat the surface of the conductor layer to form an insulation layer, then a tinned copper tape was wrapped on the surface of the insulation layer to form a shielding layer, and finally 95 g of polyvinyl chloride resin, 30 g of polyethylene resin were placed in a vacuum oven and dried at 80 °C for 2 h, then 16 g of modified talc powder prepared in Example 2, 12 g of functional additive prepared in Example 3 and 6 g of oleic acid amide were added into the extruder, after melt blending, extruded to coat the surface of the shielding layer to obtain an insulated power cable.

[0028] Comparative Example 1 Different from Example 6, the ordinary talc powder was used to replace the modified talc powder in Example 6, and the remaining steps were the same as Example 6 to prepare the material.

[0029] Comparative Example 2 Different from Example 6, no functional additive was added, and the remaining steps were the same as Example 6 to prepare the material.

[0030] Comparative Example 3 A commercially available PVC cable material was used.

[0031] Example 4, 5, 6 and Comparative Examples 1, 2, 3 were subjected to the following performance tests: The tensile strength of the test is determined by using the national standard GB / T 1040.1-2018 “Determination of tensile properties of plastics”; The sample is immersed in distilled water, soaked at room temperature for 7 days, the tensile strength (GB / T 1040.1-2018) is determined, and the retention rate of tensile strength is calculated; the retention rate of tensile strength = tensile strength after test / tensile strength before test x 100%; The sample is placed in a hot aging oven at 80℃ for 7 days, the tensile strength (GB / T 1040.1-2018) is determined, and the retention rate of tensile strength is calculated; According to the standard ASTM D543, the sample is immersed in 10% hydrochloric acid or sodium hydroxide solution respectively for 7 days, the tensile strength (GB / T 1040.1-2018) is determined, and the retention rate of tensile strength is calculated; The measured results are shown in the following table:

[0032] From the above table, it can be seen that the material of the outer sheath layer prepared by the embodiment of the present application has higher heat resistance, corrosion resistance and water resistance than the comparative examples, and excellent mechanical properties, and as one of the components of the insulated cable, it can greatly enhance the environmental adaptability of the cable, therefore, the present application has important application value in the field of power cable technology.

[0033] The above is only a preferred embodiment of the present application, and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An insulated power cable, comprising, from inside to outside: The conductor layer, the insulating layer, the shielding layer and the outer sheath layer are characterized in that the material of the outer sheath layer includes the following raw materials in parts by weight: 83-95 parts of polyvinyl chloride resin, 20-30 parts of polyethylene resin, 8-16 parts of modified talc powder, 4-12 parts of functional additives, and 3-6 parts of lubricant.

2. An insulated power cable according to claim 1, characterized in that: The functional additive is prepared by the following steps: Step B1: pentafluoroaniline, 3-mercaptopropionic acid, and anhydrous dichloromethane were added to a reaction kettle. After nitrogen was introduced, N,N-diisopropylethylamine was added dropwise under an ice bath. After stirring, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were added. The ice bath was removed, and the temperature was raised to 40° C. for 12 h. The reaction was completed to obtain an amidation product. Step B2: Add the amidation product, azobisisobutyronitrile and anhydrous toluene to the reactor, stir, introduce nitrogen, add tetramethyltetravinylcyclotetrasiloxane dropwise, and react at 70° C. for 8 h. Stir continuously during the reaction process until the reaction is completed to obtain a functional additive.

3. An insulated power cable according to claim 2, characterized in that: In step B1, the ratio of pentafluoroaniline, 3-mercaptopropionic acid, anhydrous dichloromethane, N,N-diisopropylethylamine, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide is 18.1 g:10.6 g:200 mL:25.8:22.3 g:11.5 g.

4. The insulated power cable according to claim 2, characterized in that: In step B2, the ratio of the amidated product, azobisisobutyronitrile, anhydrous dichloromethane, anhydrous toluene, and tetramethyltetravinylcyclotetrasiloxane used is 111.7 g:1.6 g:200 mL:34.4 g.

5. The insulated power cable according to claim 1, characterized in that: The modified talc is prepared by the following steps: Step A1, drying talcum powder to obtain dry talcum powder; Step A2: dissolving stearic acid in anhydrous ethanol, ultrasonically treating the mixture, adding the dried talc obtained in step A1, adjusting the pH of the reaction system to 4-5, and reacting at 70° C. for 2 h. The reaction is completed to obtain modified talc.

6. The insulated power cable according to claim 1, characterized in that: The mass ratio of the talc powder to stearic acid is 100:3-9.

7. The insulated power cable according to claim 1, characterized in that: The lubricant is one of stearic acid, glycerol monostearate, polyethylene wax and oleamide.

8. The insulated power cable according to claim 1, characterized in that: The conductor layer is made of oxygen-free copper.

9. The insulated power cable according to claim 1, characterized in that: The insulating layer is made of polyvinyl chloride.

10. The insulated power cable according to claim 1, characterized in that: The material of the shielding layer is tinned copper tape.

Images