Insulated cable material and method for producing the same

Abstract

The application relates to the technical field of cable materials, in particular to an insulating cable material and a preparation method thereof. A large number of'sea-island' interface structures exist in a PP / SEBS blended material body, and charges generated by electrode injection and polarization are prone to accumulating at the'sea-island' interface, so that space charge accumulation is caused, and the voltage breakdown field strength of the material is reduced. Based on the above problems, the application provides an insulating cable material, wherein long-carbon-chain modified graphene is added in the material system; the long carbon chain makes the nano-graphene sheet layer structure not prone to agglomeration; the long carbon chain can also act as a 'bridge' to accelerate the migration speed of carriers in SEBS in all directions, so that the difference between the number of carriers reaching and leaving the'sea-island' interface in the polarization process of the PP / SEBS blended material is reduced, and the space charge accumulation phenomenon at the interface is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, and in particular to an insulating cable material and its preparation method. Background Technology

[0002] Environmental protection and energy conservation have become a global trend, and the wire and cable industry has begun to focus on the development and promotion of environmentally friendly cables. XLPE is a thermosetting material, and as an insulating cable material, it cannot be reused after decommissioning; incineration or landfilling causes serious environmental damage. Under the new circumstances, wires and cables primarily made of cross-linked polyethylene can no longer represent the global trend of green, environmentally friendly, modern, and sustainable development.

[0003] Currently, thermoplastic insulating materials have received widespread attention from researchers in the field of dielectrics. Thermoplastic electrical insulating materials can be recycled after decommissioning, meeting the environmental requirements of sustainable development. Polypropylene is a common thermoplastic material with a melting temperature exceeding 150℃ and can operate continuously at 90℃. Polypropylene's short-time breakdown field strength can reach approximately 300kV, its volume resistivity does not change significantly with increasing temperature, its space charge accumulation is minimal, and it is almost unaffected by ambient humidity, making it a potential high-voltage cable insulation material.

[0004] However, polypropylene has high crystallinity and exhibits high modulus within its operating temperature range, resulting in strong molecular rigidity and poor toughness. This makes it prone to brittle cracking at low temperatures, significantly impacting the manufacturing, transportation, installation, laying, and operation of wires and cables. Toughening polypropylene with elastomers is the most common method. However, after applying elastomers to modify polypropylene, the breakdown strength of the blend material significantly decreases, and the amount of space charge accumulation increases. This phenomenon is due to the easy accumulation of charge at the interface between the elastomer and polypropylene. Studies have shown that PP / SEBS blends contain numerous "sea-island" interface structures, where electrode-injected and polarization-generated charges easily accumulate. Since the migration rates of charge carriers differ in different media, the number of charge carriers reaching the "sea-island" interface is not synchronized with the number leaving, thus easily leading to the accumulation of space charge at the "sea-island" interface. When the elastomer SEBS is introduced into the PP matrix, the PP spherulites become loose, the lamellar crystals become finer and shorter, the PP molecular chains become more relaxed and mobile, and the rate of carrier migration between molecular chains increases. This makes it very easy for a large number of space charge accumulations to form at the "sea-island" interface junctions in the PP / SEBS blend material, resulting in the dielectric properties of the PP / SEBS blend material being lower than those of PP.

[0005] Studies have shown that introducing nanoparticles into PP / elastomer blends can significantly improve the dielectric properties of the blends, increase the breakdown voltage, and reduce space charge accumulation. This is because the melt blending of nanoparticles with the polypropylene matrix creates numerous nanoparticle-matrix interfaces. Under applied voltage, these interfaces form numerous deep traps, inhibiting the formation of space charge within the material. While introducing nanoparticles into PP / SEBS blends can improve the dielectric properties to some extent, further improvements in the dielectric properties of the PP / SEBS blend system are still needed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that there are a large number of "sea-island" interface structures in the PP / SEBS blend material. The charge injected by the electrode and the charge generated by polarization are easy to accumulate at the "sea-island" interface, which can easily cause space charge accumulation and reduce the withstand voltage breakdown field strength of the material.

[0007] The technical solution adopted by the present invention to solve its technical problem is as follows: The present invention provides an insulating cable material, which, by weight, comprises the following components:

[0008] 70-80 PP

[0009] 20-30 parts of elastomer

[0010] Antioxidant 0.1-0.5 parts

[0011] 0.5-2 parts of modified graphene

[0012] 1-5 parts of nano-silica.

[0013] Specifically, the elastomer is SEBS.

[0014] Specifically, the antioxidant is antioxidant 1010, antioxidant 1076, or antioxidant 1035.

[0015] Specifically, the modified graphene is prepared according to the following steps:

[0016] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0017] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, and then wash it with anhydrous ethanol and deionized water 3-5 times in sequence. Finally, place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0018] Specifically, the aforementioned insulating cable material is prepared according to the following steps:

[0019] According to the formula, place the elastomer and modified graphene in a torque rheometer and melt-blend for 8-10 minutes. Then add PP and antioxidant and melt-blend for 10-12 minutes. Finally, add modified nanoparticles and melt-blend for 3-5 minutes to obtain the insulated cable material.

[0020] The beneficial effects of this invention are:

[0021] (1) The present invention adopts a special feeding sequence, so that the modified nanoparticles are mainly distributed at the "sea-island" interface of the PP / SEBS blend material. The introduction of modified nanoparticles can form a deep trap at the "sea-island" interface, which can effectively improve the breakdown field strength of the blend material and suppress the accumulation of space charge.

[0022] (2) The PP / SEBS blend material contains a large number of "sea-island" interface structures, and the charge injected by the electrode and the charge generated by polarization are easy to accumulate at the "sea-island" interface. The physical cross-linking network formed between polystyrene segments in the internal structure of SEBS reduces the migration speed of charge carriers. In this invention, hexadecyltrimethoxysilane is used to modify graphene and introduce long carbon chains into the graphene sheet structure. On the one hand, it increases the contact distance between the nano-graphene sheet structures, making it less prone to agglomeration and easier to mechanically disperse. On the other hand, the long carbon chains on the surface of the nano-graphene sheet structure can also act as "bridges", making it easier to form "contact long chains" between the nano-graphene sheets, which accelerates the migration speed of charge carriers in SEBS in all directions. This reduces the difference in the number of charge carriers arriving and leaving during the polarization process at the "sea-island" interface of the PP / SEBS blend material, effectively improving the space charge accumulation phenomenon at the interface.

[0023] (3) Under the combined effects of elastomer, antioxidant, nanoparticle and modified graphene, the insulating cable material prepared by the present invention has a large DC breakdown field strength and excellent mechanical properties. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the embodiments.

[0025] The PP used in the following embodiments of the present invention is isotactic polypropylene produced by Sinopec, with an isotacticity of 96% and a density of 0.905 g / cm³. 3 The melt flow rate (MFR) is 3.2 g / 10 min, the shrinkage rate is 1.8-2.5%, and the extrusion temperature is 180-260℃.

[0026] The nano-silica used in the following embodiments of the present invention is Degussa hydrophobic fumed silica R812S, with a particle size of 8000 mesh.

[0027] The graphene oxide used in the following embodiments of the present invention is graphene oxide prepared by the improved Hummers method.

[0028] Example 1

[0029] An insulating cable material, by weight, comprises the following components:

[0030] 70 PP

[0031] SEBS 20 copies

[0032] Antioxidant 1010 0.1 parts

[0033] 0.5 parts modified graphene

[0034] 1 part of nano-silica;

[0035] The modified graphene is prepared according to the following steps:

[0036] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0037] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, wash it three times with anhydrous ethanol and deionized water in sequence, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0038] The insulating cable material is prepared according to the following steps:

[0039] According to the formula, the elastomer and modified graphene are placed in a torque rheometer and melt-blended for 8 minutes. Then, PP and antioxidant are added and melt-blended for 10 minutes. Finally, modified nanoparticles are added and melt-blended for 3 minutes to obtain the insulating cable material.

[0040] Example 2

[0041] An insulating cable material, by weight, comprises the following components:

[0042] 72 PP

[0043] SEBS 20 copies

[0044] Antioxidant 1076 0.2 parts

[0045] 0.5 parts modified graphene

[0046] One part of nano-silica.

[0047] The modified graphene is prepared according to the following steps:

[0048] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0049] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, wash it three times with anhydrous ethanol and deionized water in sequence, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0050] The insulating cable material is prepared according to the following steps:

[0051] According to the formula, the elastomer and modified graphene are placed in a torque rheometer and melt-blended for 10 minutes. Then, PP and antioxidant are added and melt-blended for 12 minutes. Finally, modified nanoparticles are added and melt-blended for 5 minutes to obtain the insulating cable material.

[0052] Example 3

[0053] An insulating cable material, by weight, comprises the following components:

[0054] PP 75 copies

[0055] SEBS 22 copies

[0056] Antioxidant 1035 0.2 parts

[0057] 0.6 parts modified graphene

[0058] Two parts of nano-silica.

[0059] The modified graphene is prepared according to the following steps:

[0060] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0061] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, wash it three times with anhydrous ethanol and deionized water in sequence, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0062] The insulating cable material is prepared according to the following steps:

[0063] According to the formula, the elastomer and modified graphene are placed in a torque rheometer and melt-blended for 9 minutes. Then, PP and antioxidant are added and melt-blended for 10 minutes. Finally, modified nanoparticles are added and melt-blended for 4 minutes to obtain the insulating cable material.

[0064] Example 4

[0065] An insulating cable material, by weight, comprises the following components:

[0066] 70 PP

[0067] SEBS 20 copies

[0068] Antioxidant 1010 0.1 parts

[0069] 1.5 parts of nano-silica.

[0070] The insulating cable material is prepared according to the following steps:

[0071] According to the formula, the elastomer, PP and antioxidant are placed in a torque rheometer and melt-blended for 18 minutes. Then, nano-silica is added and melt-blended for 3 minutes to obtain the insulated cable material.

[0072] Example 5

[0073] An insulating cable material, by weight, comprises the following components:

[0074] 70 PP

[0075] SEBS 20 copies

[0076] Antioxidant 1010 0.1 parts

[0077] 0.5 parts of graphene oxide

[0078] 1 part of nano-silica;

[0079] The insulating cable material is prepared according to the following steps:

[0080] According to the formula, the elastomer and graphene oxide are placed in a torque rheometer and melt-blended for 8 minutes. Then, PP and antioxidant are added and melt-blended for 10 minutes. Finally, modified nanoparticles are added and melt-blended for 3 minutes to obtain the insulating cable material.

[0081] Example 6

[0082] An insulating cable material, by weight, comprises the following components:

[0083] 70 PP

[0084] SEBS 20 copies

[0085] Antioxidant 1010 0.1 parts

[0086] 0.5 parts of KH570 modified graphene

[0087] 1 part of nano-silica;

[0088] The KH570 modified graphene is prepared according to the following steps:

[0089] (1) 100 mg of graphene oxide was added to deionized water and ultrasonically dispersed to obtain a graphene dispersion of 30 mg / mL.

[0090] (2) Add 100g of DMF to 100mL of graphene dispersion and disperse evenly by ultrasonication to obtain G-DMF dispersion;

[0091] (3) The water in the G-DMF dispersion was evaporated by a rotary evaporator, and the dispersion was ultrasonically dispersed for 2 hours. Then it was transferred to a reaction vessel and heated in a water bath at 65°C.

[0092] (4) 15g of KH570 ethanol aqueous solution with pH=5 was added dropwise to the reaction vessel in step (3) and the addition was completed within 1 hour. The reaction was then carried out at a constant temperature for 12 hours. After that, the reaction product was centrifuged and dried to obtain KH570 modified graphene. The mass ratio of KH570 to water and ethanol in the KH570 ethanol aqueous solution was 3:1:10, and the pH adjuster was hydrochloric acid.

[0093] The insulating cable material is prepared according to the following steps:

[0094] According to the formula, the elastomer and KH570 modified graphene are placed in a torque rheometer and melt-blended for 8 minutes. Then, PP and antioxidant are added and melt-blended for 10 minutes. Finally, modified nanoparticles are added and melt-blended for 3 minutes to obtain the insulating cable material.

[0095] Example 7

[0096] An insulating cable material, by weight, comprises the following components:

[0097] PP 80 copies

[0098] SEBS 30 copies

[0099] Antioxidant 1076 0.5 parts

[0100] 2 parts of modified graphene

[0101] Five parts of nano-silica.

[0102] The modified graphene is prepared according to the following steps:

[0103] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0104] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, wash it four times with anhydrous ethanol and deionized water in sequence, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0105] The insulating cable material is prepared according to the following steps:

[0106] According to the formula, the elastomer and modified graphene are placed in a torque rheometer and melt-blended for 9 minutes. Then, PP and antioxidant are added and melt-blended for 11 minutes. Finally, modified nanoparticles are added and melt-blended for 4 minutes to obtain the insulating cable material.

[0107] Example 8

[0108] An insulating cable material, by weight, comprises the following components:

[0109] PP 75 copies

[0110] SEBS 26 copies

[0111] Antioxidant 1035 0.4 parts

[0112] 1.2 parts modified graphene

[0113] Three parts of nano-silica.

[0114] The modified graphene is prepared according to the following steps:

[0115] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0116] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, wash it 5 times with anhydrous ethanol and deionized water in sequence, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0117] The insulating cable material is prepared according to the following steps:

[0118] According to the formula, the elastomer and modified graphene are placed in a torque rheometer and melt-blended for 8 minutes. Then, PP and antioxidant are added and melt-blended for 12 minutes. Finally, modified nanoparticles are added and melt-blended for 4 minutes to obtain the insulated cable material.

[0119] Example 9

[0120] An insulating cable material, by weight, comprises the following components:

[0121] 74 PP

[0122] SEBS 25 copies

[0123] Antioxidant 1035 0.3 parts

[0124] 1.5 parts modified graphene

[0125] Four parts of nano-silica.

[0126] The modified graphene is prepared according to the following steps:

[0127] (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion.

[0128] (2) Transfer the GO dispersion to a three-necked flask, and under nitrogen protection, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane in sequence. After stirring evenly, react at 110 °C overnight. After the reaction is complete, filter the reaction product, wash it 5 times with anhydrous ethanol and deionized water in sequence, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene.

[0129] The insulating cable material is prepared according to the following steps:

[0130] According to the formula, the elastomer and modified graphene are placed in a torque rheometer and melt-blended for 8 minutes. Then, PP and antioxidant are added and melt-blended for 12 minutes. Finally, modified nanoparticles are added and melt-blended for 3 minutes to obtain the insulating cable material.

[0131] Comparative Example 1 is the same as Example 1, except that the insulating cable material in Comparative Example 1 is prepared according to the following steps:

[0132] According to the formula, PP, antioxidant, and modified nanoparticles are placed in a torque rheometer and melt-blended for 10 minutes. Then, SEBS is added and melt-blended for 8 minutes. Finally, modified graphene is added and melt-blended for 3 minutes to obtain the insulated cable material.

[0133] Comparative Example 2 is the same as Example 1, except that the insulating cable material in Comparative Example 2 is prepared according to the following steps:

[0134] According to the formula, PP, antioxidant, and modified graphene are placed in a torque rheometer and melt-blended for 10 minutes. Then, SEBS is added and melt-blended for 8 minutes. Finally, modified nanoparticles are added and melt-blended for 3 minutes to obtain the insulated cable material.

[0135] Comparative Example 3 is the same as Example 1, except that the insulating cable material in Comparative Example 3 is prepared according to the following steps:

[0136] According to the formula, PP, antioxidant, modified graphene, SEBS, and modified nanoparticles are placed in a torque rheometer and melt-blended for 21 minutes to obtain the insulated cable material.

[0137] Performance testing:

[0138] (1) Mechanical property testing

[0139] Tensile strength and elongation at break were tested in accordance with GB / T1040. The specimens were type II dumbbell plates with a thickness of 1.0 mm. The tests were conducted using a CMT series temperature-controlled universal testing machine with a tensile speed of 250 mm / min.

[0140] (2) Electrical performance testing

[0141] The dielectric constant test was conducted according to GB / T1409, with a frequency of 50Hz, an ambient temperature of 20℃, and a sample thickness of 1.0mm. The DC breakdown field strength test used a ZGF portable DC high-voltage generator from Shanghai Huidong Electrical Equipment Co., Ltd., with 25mm diameter ball-to-ball electrodes. The test temperatures were room temperature and 90℃. The sample was immersed in high-temperature resistant RAPO vegetable oil. At 90℃, the vegetable oil used to immerse the electrodes was placed in a 90℃ oven to heat the oil. The oil temperature was monitored and maintained at 90℃ throughout the test. The voltage ramp rate was 1kV / s until the sample broke down.

[0142] The insulated cable materials obtained in Examples 1-9 and Comparative Examples 1-3 were tested according to the above method, and the performance test results are shown in Table 1.

[0143] Table 1

[0144]

[0145] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An insulating cable material, characterized in that, By weight, it includes the following ingredients: 70-80 PP 20-30 parts of elastomer Antioxidant 0.1-0.5 parts 0.5-2 parts of modified graphene 1-5 parts of nano-silica; The modified graphene is prepared according to the following steps: (1) Weigh 200 mg of GO and dissolve it in 100 mL of DMF. Disperse the GO mixture evenly by ultrasonication to obtain a GO dispersion. (2) Transfer the GO dispersion to a three-necked flask, add 0.3 mL of triethylamine and 2.5 g of hexadecyltrimethoxysilane under nitrogen protection, stir evenly, and react overnight at 110 °C. After the reaction is complete, filter the reaction product, wash it 3-5 times with anhydrous ethanol and deionized water, and finally place it in a vacuum drying oven at 80 °C for 24 h to obtain modified graphene. Furthermore, the insulating cable material is prepared according to the following steps: According to the formula, place the elastomer and modified graphene in a torque rheometer and melt-blend for 8-10 minutes. Then add PP and antioxidant and melt-blend for 10-12 minutes. Finally, add nano-silica and melt-blend for 3-5 minutes to obtain the insulated cable material.

2. The insulating cable material according to claim 1, characterized in that, The elastomer is SEBS.

3. The insulating cable material according to claim 1, characterized in that, The antioxidant is antioxidant 1010, antioxidant 1076, or antioxidant 1035.

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