High-Temperature Insulating Modified Polypropylene Cable Material and its Preparation Method

Abstract

This invention discloses a high-temperature resistant, insulating modified polypropylene cable material and its preparation method, relating to the field of cable material technology. The method for preparing the high-temperature resistant, insulating modified polypropylene cable material includes the following steps: according to the raw material composition ratio, polypropylene resin and nanoparticle-modified elastomer are mixed, and functional additives are added during mixing to obtain the high-temperature resistant, insulating modified polypropylene cable material. This application incorporates nanoparticle-modified elastomer into the polypropylene base material, effectively improving the mechanical toughness of the polypropylene resin while maintaining its excellent heat resistance and insulation properties.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, specifically to high-temperature resistant insulating modified polypropylene cable material and its preparation method. Background Technology

[0002] With social progress and economic development, the demand for electricity is gradually increasing. Compared with AC transmission, high-voltage direct current (HVDC) transmission has the advantages of lower line loss and easier adjustment of transmission power and direction, giving it significant advantages in large-capacity long-distance power transmission, interconnection of power grids with different frequencies, or asynchronous interconnection of power grids with the same frequency. HVDC cables are crucial equipment in DC transmission systems, and the development of HVDC polypropylene cable insulation materials is of great significance to the development of HVDC cables. However, under the long-term influence of a DC electric field, HVDC cable insulation materials are prone to space charge accumulation, causing local electric field distortion and accelerating insulation aging. Moreover, during cable operation, the insulation is also subjected to high temperatures and combined DC and pulse voltages, which can easily lead to insulation thermal aging and electrical treeing deterioration, threatening the safe operation of the cable transmission system.

[0003] Polyethylene and cross-linked polyethylene are common cable insulation materials, both possessing excellent electrical properties. However, they are somewhat lacking in heat resistance and environmental friendliness. Polyethylene has poor heat resistance; the melting point of commonly used low-density polyethylene is only around 110℃, which is insufficient to meet the operating temperature requirements of high-voltage, high-capacity cables. While cross-linked polyethylene improves heat resistance compared to polyethylene, it suffers from difficulties in recycling, complex processing, high processing costs, and unstable electrical properties. Thermoplastic polypropylene (PP), on the other hand, possesses excellent heat resistance and insulation properties, high mechanical strength, does not require cross-linking treatment, and is recyclable, meeting the development needs of high-temperature resistant cable insulation materials.

[0004] Polypropylene (PP) can be classified into isotactic, syndiotactic, and atactic polypropylene based on the position of methyl groups on its main chain. Among these three types, isotactic PP possesses numerous advantages, including good electrical insulation, high heat resistance, and thermoplastic recyclability, making it a potential candidate for cable insulation. However, its insufficient mechanical toughness makes it difficult to meet cable performance requirements, and it is prone to space charge accumulation under the influence of a DC electric field. Existing technologies improve the weaknesses of the matrix material through blending modification, thereby enhancing material performance. Currently, the most commonly used blending materials are various elastomers. Blending elastomers with PP alters the molecular structure of the PP matrix material, leading to changes in the mechanical and electrical properties of PP. Commonly used elastomers include EPDM rubber, polyolefin elastomers, EPDM rubber, butadiene rubber, styrene-butadiene-styrene block copolymers, and ethylene-vinyl acetate copolymers. However, improving the toughness of PP cable materials often sacrifices its heat resistance and insulation properties, affecting the practical application of the material. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant, insulating modified polypropylene cable material and its preparation method, thereby solving the following technical problems:

[0006] Existing polypropylene cable materials improve mechanical toughness by adding elastomers, but this reduces heat resistance and insulation, affecting the material's practical application.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] The preparation method of high-temperature resistant modified polypropylene cable insulation material includes the following steps:

[0009] Based on the raw material composition ratio, polypropylene resin and nanoparticle modified elastomer are mixed and compounded, and functional additives are added to obtain high-temperature resistant insulating modified polypropylene cable material.

[0010] The preparation method of nanoparticle-modified elastomers includes the following steps:

[0011] S1: Add composite nanoparticles, anhydrous ethanol, and deionized water to a reaction vessel for dispersion, adjust the pH to 4-5, add vinyltriethoxysilane, control the temperature at 60-65℃ and react for 6-8 hours, centrifuge, wash, and dry to obtain organic composite nanoparticles.

[0012] S2: Under a nitrogen atmosphere, SEBS particles and toluene are added to a reactor, along with styrene and dicumyl peroxide. The temperature is controlled at 110-120℃ and the reaction is refluxed for 4-6 hours. Methanol is added to precipitate the product, followed by washing and drying to obtain the modified elastomer.

[0013] S3: In a nitrogen atmosphere, organic composite nanoparticles and toluene are added to a reaction vessel for dispersion. Modified elastomer and toluene are mixed and added to the reaction vessel. Diisopropylbenzene peroxide is added. The temperature is controlled at 100-110℃ and the reaction is carried out for 6-8 hours. The mixture is then added to methanol for precipitation, extraction, and drying to obtain nanoparticle modified elastomer.

[0014] The composite nanoparticles are titanium dioxide particles deposited on the surface of mesoporous silica.

[0015] As a further embodiment of the present invention: the addition ratio of composite nanoparticles, anhydrous ethanol, deionized water and vinyltriethoxysilane in S1 is 10g:80-90mL:10-20mL:3-5g.

[0016] As a further embodiment of the present invention: the addition ratio of SEBS particles, toluene, styrene and diisopropylbenzene peroxide in S2 is 100g: 1000-2000mL: 5-10g: 0.1-0.3g.

[0017] As a further aspect of the present invention: the addition ratio of organic composite nanoparticles, modified elastomer, and dicumyl peroxide in S3 is 10g: 85-95g: 0.1-0.2g.

[0018] As a further aspect of the present invention, the method for preparing composite nanoparticles includes the following steps:

[0019] A1: Add hexadecyltrimethylammonium bromide, water, and sodium hydroxide to a reaction vessel, control the temperature at 70-80℃, stir and react for 1-2 hours, add tetraethyl orthosilicate, keep the reaction at the temperature for 1-2 hours, centrifuge, wash, dry, and calcine to obtain mesoporous silica.

[0020] A2: In a nitrogen atmosphere, mesoporous silica and anhydrous ethanol are added to a reaction vessel, and the temperature is controlled at 0-5℃. Tetrabutyl titanate is added, and the mixture is kept warm and stirred for 12-15 hours. The temperature is controlled at 100-120℃, and the hydrothermal reaction is carried out for 12-24 hours. The mixture is then centrifuged, washed, dried, and calcined to obtain composite nanoparticles.

[0021] As a further embodiment of the present invention: the addition ratio of hexadecyltrimethylammonium bromide, water, sodium hydroxide and tetraethyl orthosilicate in A1 is 1-2g: 120-200mL: 0.25-0.4g: 2-4g.

[0022] As a further aspect of the present invention: the addition ratio of A2 mesoporous silica, anhydrous ethanol, and tetrabutyl titanate is 10g: 100-200mL: 0.5-1.5g.

[0023] As a further aspect of the present invention, the mass ratio of polypropylene resin to nanoparticle-modified elastomer is 100:20-35.

[0024] As a further aspect of the present invention: the functional additives include antioxidants and flame retardants; the antioxidants are one or more of antioxidant 1010, antioxidant 2246 or antioxidant 264 mixed in any proportion; the flame retardants are one or more of magnesium hydroxide, aluminum hydroxide or antimony trioxide mixed in any proportion.

[0025] As a further aspect of the present invention: the mass ratio of antioxidant to polypropylene resin is 0.5-1:100; the mass ratio of flame retardant to polypropylene resin is 2-5:100.

[0026] As a further aspect of the present invention, the functional additives also include glyceryl stearate; the mass ratio of glyceryl stearate to polypropylene resin is 2-8:100.

[0027] High-temperature resistant insulating modified polypropylene cable material is prepared by any of the above preparation methods.

[0028] The beneficial effects of this invention are:

[0029] This application uses mesoporous silica as a carrier and loads titanium dioxide onto its surface to obtain composite nanoparticles, which serve as the functional core. The surface of these nanoparticles is then organically treated to obtain organically modified composite nanoparticles. This application introduces benzene rings into the SEBS molecular chain to obtain a modified elastomer. Finally, this application bonds the organically modified composite nanoparticles to the modified elastomer via chemical bonds to obtain a nanoparticle-modified elastomer.

[0030] (1) Effectively improve mechanical toughness

[0031] In nanoparticle-modified elastomers, SEBS elastomers, serving as the shell layer and acting as the primary toughening phase, effectively induce crazes and shear bands through their good compatibility with polypropylene and their own elasticity, absorbing impact energy. The composite nanoparticles, as rigid particles, also contribute to the toughening effect. The core-shell structure avoids stress concentration points caused by the aggregation of composite nanoparticles.

[0032] (2) Maintenance of DC dielectric properties

[0033] The composite nanoparticles prepared in this application confine titanium dioxide within the nanopores of mesoporous silica, acting as a nanocharge pump or charge buffer. Their semiconductor properties, shielded by the mesoporous silica, promote charge migration and neutralization within a very localized area (nanoscale), preventing charge accumulation at the interface without inducing long-range charge injection and migration. The insulating properties of mesoporous silica solve the macroscopic electric field distortion problem caused by the high dielectric constant of titanium dioxide, and the mesoporous channels provide physical scattering and confinement for charge transport. The mesoporous silica itself and its interface with titanium dioxide introduce numerous deep traps, effectively binding charges. This structure combines the field homogenization and deep trap advantages of mesoporous silica with the charge migration characteristics of titanium dioxide, while avoiding their respective drawbacks.

[0034] This application uses a modified elastomer as a shell to coat the surface of composite nanoparticles. The introduced benzene rings form appropriate deep traps to capture charge carriers, reduce mobility, and suppress charge injection. Utilizing its delocalized π-electron cloud, the volume resistivity and DC breakdown strength are improved, while space charge is suppressed. Compared to directly grafting polar groups such as maleic anhydride onto polypropylene, this method completes the grafting reaction, which could potentially cause polypropylene degradation, on the elastomer in advance, avoiding degradation of the polypropylene backbone during processing and protecting its electrical properties. Styrene optimizes the density of the deep traps, preventing the introduction of too many traps that become charge accumulation centers. This effectively suppresses space charge accumulation while maintaining high DC breakdown strength.

[0035] The nanoparticle-modified elastomer prepared in this application effectively increases the mechanical toughness of the cable material when added to it, which helps to reduce the DC conductivity current of the composite material and suppress the accumulation of space charge, and can also improve the DC breakdown strength of the material; it also regulates the charge transport characteristics of the polymer and improves the electrical properties of the polymer. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1: The preparation method of nanoparticle-modified elastomer includes the following steps:

[0038] S1: Add 5g hexadecyltrimethylammonium bromide, 600mL water, and 1.25g sodium hydroxide to a reaction vessel, control the temperature at 70℃, stir and react for 1h, add 20g tetraethyl orthosilicate, keep the reaction at the temperature for 1h, centrifuge, wash, dry, and calcine at 550℃ for 5h to obtain mesoporous silica.

[0039] In a nitrogen atmosphere, 10g of mesoporous silica and 100mL of anhydrous ethanol were added to a reaction vessel. The temperature was controlled at 0℃. 0.5g of tetrabutyl titanate was added. The mixture was kept warm and stirred for 12h. The temperature was controlled at 100℃ and the hydrothermal reaction was carried out for 12h. The mixture was then centrifuged, washed, dried, and calcined at 500℃ for 3h to obtain composite nanoparticles.

[0040] S2: 10g of composite nanoparticles, 80mL of anhydrous ethanol and 20mL of deionized water were added to the reaction vessel and dispersed. The pH was adjusted to 4, 3g of vinyltriethoxysilane was added, the temperature was controlled at 60℃ and the reaction was carried out for 6h. After centrifugation, washing and drying, organic composite nanoparticles were obtained.

[0041] S3: Under a nitrogen atmosphere, 100g of SEBS particles (YH-502) and 1000mL of toluene were added to a reactor, along with 5g of styrene and 0.1g of dicumyl peroxide. The temperature was controlled at 110℃ and the reaction was refluxed for 4h. Methanol was added to precipitate the product, and the product was washed and dried to obtain the modified elastomer.

[0042] S4: In a nitrogen atmosphere, 10g of organic composite nanoparticles and toluene were added to the reactor for dispersion. 85g of modified elastomer and toluene were mixed and added to the reactor. 0.1g of dicumyl peroxide was added. The temperature was controlled at 100℃ and the reaction was carried out for 6 hours. The mixture was poured into methanol for precipitation, extraction and drying to obtain nanoparticle modified elastomer.

[0043] Example 2: The preparation method of nanoparticle-modified elastomer includes the following steps:

[0044] S1: Add 7g hexadecyltrimethylammonium bromide, 600mL water, and 1.5g sodium hydroxide to a reaction vessel, control the temperature at 75℃, stir and react for 1.5h, add 20g tetraethyl orthosilicate, keep the reaction at the temperature for 1.5h, centrifuge, wash, dry, and calcine at 550℃ for 5h to obtain mesoporous silica.

[0045] In a nitrogen atmosphere, 10g of mesoporous silica and 100mL of anhydrous ethanol were added to a reaction vessel, the temperature was controlled at 0℃, 1g of tetrabutyl titanate was added, the mixture was kept warm and stirred for 15h, the temperature was controlled at 110℃ and the hydrothermal reaction was carried out for 18h, centrifuged, washed, dried and calcined at 500℃ for 3h to obtain composite nanoparticles.

[0046] S2: 10g of composite nanoparticles, 80mL of anhydrous ethanol and 20mL of deionized water were added to the reaction vessel and dispersed. The pH was adjusted to 4. 5g of vinyltriethoxysilane was added. The temperature was controlled at 60℃ and the reaction was carried out for 7h. After centrifugation, washing and drying, organic composite nanoparticles were obtained.

[0047] S3: Under a nitrogen atmosphere, 100g of SEBS particles (YH-502) and 1000mL of toluene were added to a reactor, along with 7g of styrene and 0.2g of dicumyl peroxide. The temperature was controlled at 115℃ and the reaction was refluxed for 5h. Methanol was added to precipitate the product, and the product was washed and dried to obtain the modified elastomer.

[0048] S4: In a nitrogen atmosphere, 10g of organic composite nanoparticles and toluene were added to the reactor for dispersion. 85g of modified elastomer and toluene were mixed and added to the reactor. 0.1g of dicumyl peroxide was added. The temperature was controlled at 105℃ and the reaction was carried out for 7h. The mixture was poured into methanol for precipitation, extraction and drying to obtain nanoparticle modified elastomer.

[0049] Example 3: The preparation method of nanoparticle-modified elastomer includes the following steps:

[0050] S1: Add 10g hexadecyltrimethylammonium bromide, 1000mL water and 2g sodium hydroxide to a reaction vessel, control the temperature at 80℃ and stir for 2h, add 20g tetraethyl orthosilicate, keep the temperature for 2h, centrifuge, wash, dry and calcine at 550℃ for 5h to obtain mesoporous silica.

[0051] In a nitrogen atmosphere, 10g of mesoporous silica and 200mL of anhydrous ethanol were added to a reaction vessel, the temperature was controlled at 5℃, 1.5g of tetrabutyl titanate was added, the mixture was kept warm and stirred for 15h, the temperature was controlled at 120℃ and the hydrothermal reaction was carried out for 24h, centrifuged, washed, dried and calcined at 500℃ for 3h to obtain composite nanoparticles.

[0052] S2: 10g of composite nanoparticles, 90mL of anhydrous ethanol and 10mL of deionized water were added to the reaction vessel and dispersed. The pH was adjusted to 5, and 5g of vinyltriethoxysilane was added. The temperature was controlled at 65℃ and the reaction was carried out for 8 hours. After centrifugation, washing and drying, organic composite nanoparticles were obtained.

[0053] S3: Under a nitrogen atmosphere, 100g of SEBS particles (YH-502) and 1000mL of toluene were added to a reactor, along with 10g of styrene and 0.3g of dicumyl peroxide. The temperature was controlled at 120℃ and the reaction was refluxed for 6 hours. Methanol was added to precipitate the product, and the product was washed and dried to obtain the modified elastomer.

[0054] S4: In a nitrogen atmosphere, 10g of organic composite nanoparticles and toluene were added to the reactor for dispersion. 85g of modified elastomer and toluene were mixed and added to the reactor. 0.2g of dicumyl peroxide was added. The temperature was controlled at 110℃ and the reaction was carried out for 8 hours. The mixture was then poured into methanol for precipitation, extraction, and drying to obtain nanoparticle-modified elastomer.

[0055] Example 4: A method for preparing high-temperature resistant modified polypropylene cable material includes the following steps: 100g of polypropylene resin (isotactic polypropylene, purchased from Sinopec Yangzi Petrochemical Co., Ltd., model F401) and 25g of nanoparticle modified elastomer prepared in Example 1 are mixed (mixing temperature 180℃, mixing for 5min), and 0.5g of antioxidant 1010, 4g of magnesium hydroxide, and 5g of glyceryl stearate are added and mixed (mixing temperature 200℃, mixing for 5min) to obtain high-temperature resistant modified polypropylene cable material.

[0056] Example 5: A method for preparing high-temperature resistant modified polypropylene cable material includes the following steps: 100g of polypropylene resin (isotactic polypropylene, purchased from Sinopec Yangzi Petrochemical Co., Ltd., model F401) and 25g of nanoparticle modified elastomer prepared in Example 2 are mixed (mixing temperature 180℃, mixing for 5min), and 0.5g of antioxidant 1010, 4g of magnesium hydroxide, and 5g of glyceryl stearate are added and mixed (mixing temperature 200℃, mixing for 5min) to obtain high-temperature resistant modified polypropylene cable material.

[0057] Example 6: A method for preparing high-temperature resistant modified polypropylene cable material includes the following steps: 100g of polypropylene resin (isotactic polypropylene, purchased from Sinopec Yangzi Petrochemical Co., Ltd., model F401) and 25g of nanoparticle modified elastomer prepared in Example 3 are mixed (mixing temperature 180℃, mixing for 5min), and 0.5g of antioxidant 1010, 4g of magnesium hydroxide, and 5g of glyceryl stearate are added and mixed (mixing temperature 200℃, mixing for 5min) to obtain high-temperature resistant modified polypropylene cable material.

[0058] Comparative Example 1: The preparation method of nanoparticle-modified elastomer includes the following steps:

[0059] S1: Add 7g hexadecyltrimethylammonium bromide, 600mL water, and 1.5g sodium hydroxide to a reaction vessel, control the temperature at 75℃, stir and react for 1.5h, add 20g tetraethyl orthosilicate, keep the reaction at the temperature for 1.5h, centrifuge, wash, dry, and calcine at 550℃ for 5h to obtain mesoporous silica.

[0060] S2: 10g of mesoporous silica, 80mL of anhydrous ethanol and 20mL of deionized water were added to the reaction vessel and dispersed. The pH was adjusted to 4. 5g of vinyltriethoxysilane was added. The temperature was controlled at 60℃ and the reaction was carried out for 7h. After centrifugation, washing and drying, organic composite nanoparticles were obtained.

[0061] S3: Under a nitrogen atmosphere, 100g of SEBS particles (YH-502) and 1000mL of toluene were added to a reactor, along with 7g of styrene and 0.2g of dicumyl peroxide. The temperature was controlled at 115℃ and the reaction was refluxed for 5h. Methanol was added to precipitate the product, and the product was washed and dried to obtain the modified elastomer.

[0062] S4: In a nitrogen atmosphere, 10g of organic composite nanoparticles and toluene were added to the reactor for dispersion. 85g of modified elastomer and toluene were mixed and added to the reactor. 0.1g of dicumyl peroxide was added. The temperature was controlled at 105℃ and the reaction was carried out for 7h. The mixture was poured into methanol for precipitation, extraction and drying to obtain nanoparticle modified elastomer.

[0063] Comparative Example 2: The preparation method of the nanoparticle-modified elastomer includes the following steps:

[0064] S1: 10g of nano titanium dioxide, 80mL of anhydrous ethanol and 20mL of deionized water were added to the reaction vessel and dispersed. The pH was adjusted to 4. 5g of vinyltriethoxysilane was added. The temperature was controlled at 60℃ and the reaction was carried out for 7h. After centrifugation, washing and drying, organic composite nanoparticles were obtained.

[0065] S2: Under a nitrogen atmosphere, 100g of SEBS particles (YH-502) and 1000mL of toluene were added to a reactor, along with 7g of styrene and 0.2g of dicumyl peroxide. The temperature was controlled at 115℃ and the reaction was refluxed for 5h. Methanol was added to precipitate the product, and the product was washed and dried to obtain the modified elastomer.

[0066] S3: In a nitrogen atmosphere, 10g of organic composite nanoparticles and toluene were added to the reactor for dispersion. 85g of modified elastomer and toluene were mixed and added to the reactor. 0.1g of dicumyl peroxide was added. The temperature was controlled at 105℃ and the reaction was carried out for 7h. The mixture was poured into methanol for precipitation, extraction and drying to obtain nanoparticle modified elastomer.

[0067] Comparative Example 3: The preparation method of the nanoparticle-modified elastomer includes the following steps:

[0068] S1: In a nitrogen atmosphere, 10g of mesoporous silica and 100mL of anhydrous ethanol were added to a reaction vessel. The temperature was controlled at 0℃. 1g of tetrabutyl titanate was added. The mixture was kept warm and stirred for 15h. The temperature was controlled at 110℃ and the hydrothermal reaction was carried out for 18h. The mixture was then centrifuged, washed, dried, and calcined at 500℃ for 3h to obtain composite nanoparticles.

[0069] S2: 10g of composite nanoparticles, 80mL of anhydrous ethanol and 20mL of deionized water were added to the reaction vessel and dispersed. The pH was adjusted to 4. 5g of vinyltriethoxysilane was added. The temperature was controlled at 60℃ and the reaction was carried out for 7h. After centrifugation, washing and drying, organic composite nanoparticles were obtained.

[0070] S3: Under a nitrogen atmosphere, 100g of SEBS particles (YH-502) and 1000mL of toluene were added to a reactor, along with 7g of styrene and 0.2g of dicumyl peroxide. The temperature was controlled at 115℃ and the reaction was refluxed for 5h. Methanol was added to precipitate the product, and the product was washed and dried to obtain the modified elastomer.

[0071] S4; 10g of organic composite nanoparticles and 85g of modified elastomer are blended to obtain nanoparticle-modified elastomer.

[0072] Compared with Example 5, Comparative Example 4 only replaced the nanoparticle-modified elastomer prepared in Example 2 with an equal amount of the nanoparticle-modified elastomer prepared in Comparative Example 1. The remaining components and preparation methods were completely the same as in Example 5.

[0073] Compared with Example 5, Comparative Example 5 only replaced the nanoparticle-modified elastomer prepared in Example 2 with an equal amount of the nanoparticle-modified elastomer prepared in Comparative Example 2. The remaining components and preparation methods were completely the same as in Example 5.

[0074] Comparative Example 6 is the same as Example 5 except that the nanoparticle-modified elastomer prepared in Example 2 is replaced in equal amounts with the nanoparticle-modified elastomer prepared in Comparative Example 1. The other components and preparation methods are completely the same as in Example 5.

[0075] Performance testing

[0076] (1) Mechanical properties: Tensile strength and elongation at break were tested according to GB / T 1040.2-2006 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics" at a tensile rate of 30 mm / min. The test results are shown in Table 1.

[0077] (2) Impact strength: The impact strength of plastic cantilever beams was tested according to GB / T 1843-2008 "Determination of impact strength of plastic cantilever beams". The test results are shown in Table 1.

[0078] Table 1: Statistical table of mechanical property test data for Examples 4-6 and Comparative Examples 4-6;

[0079]

[0080] As shown in Table 1, the nanoparticle-modified elastomer prepared in this application endows the cable material with excellent mechanical properties.

[0081] (3) DC breakdown strength: According to GB / T 1408.3-2007 "Electrical strength test methods for insulating materials - Part 3: Supplementary requirements for 1.2 / 50μs pulse test", the test results are shown in Table 2;

[0082] (4) Volume resistivity: The volume resistivity and surface resistivity of solid insulating materials were tested according to GB / T 1410-2006 "Test methods for volume resistivity and surface resistivity of solid insulating materials". The test results are shown in Table 2.

[0083] (5) Temperature resistance: The test was conducted according to GB / T 5470-2008 "Determination of embrittlement temperature of plastics by impact method". The test results are shown in Table 2.

[0084] Table 2: Statistical table of mechanical property test data for Examples 4-6 and Comparative Examples 4-6;

[0085]

[0086] As shown in Table 2, the high-temperature resistant modified polypropylene cable material prepared in this application has good insulation properties and resistance to low-temperature brittleness.

[0087] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing high-temperature resistant insulating modified polypropylene cable material, characterized in that, Includes the following steps: Based on the raw material composition ratio, polypropylene resin and nanoparticle modified elastomer are mixed and compounded, and functional additives are added to obtain high-temperature resistant insulating modified polypropylene cable material. The preparation method of the nanoparticle-modified elastomer includes the following steps: S1: Add composite nanoparticles, anhydrous ethanol, and deionized water to a reaction vessel for dispersion, adjust the pH to 4-5, add vinyltriethoxysilane, control the temperature at 60-65℃ and react for 6-8 hours, centrifuge, wash, and dry to obtain organic composite nanoparticles. S2: Under a nitrogen atmosphere, SEBS particles and toluene are added to a reactor, along with styrene and dicumyl peroxide. The temperature is controlled at 110-120℃ and the reaction is refluxed for 4-6 hours. Methanol is added to precipitate the product, followed by washing and drying to obtain the modified elastomer. S3: In a nitrogen atmosphere, organic composite nanoparticles and toluene are added to a reaction vessel for dispersion. Modified elastomer and toluene are mixed and added to the reaction vessel. Diisopropylbenzene peroxide is added. The temperature is controlled at 100-110℃ and the reaction is carried out for 6-8 hours. The mixture is then added to methanol for precipitation, extraction, and drying to obtain nanoparticle modified elastomer. The composite nanoparticles are titanium dioxide particles deposited on the surface of mesoporous silica; The addition ratio of composite nanoparticles, anhydrous ethanol, deionized water, and vinyltriethoxysilane in S1 is 10g: 80-90mL: 10-20mL: 3-5g; The addition ratio of SEBS particles, toluene, styrene, and dicumyl peroxide in S2 is 100g: 1000-2000mL: 5-10g: 0.1-0.3g; The addition ratio of organic composite nanoparticles, modified elastomers, and dicumyl peroxide in S3 is 10g: 85-95g: 0.1-0.2g; The mass ratio of the polypropylene resin to the nanoparticle-modified elastomer is 100:20-35.

2. The preparation method of the high-temperature resistant insulating modified polypropylene cable material according to claim 1, characterized in that, The preparation method of the composite nanoparticles includes the following steps: A1: Add hexadecyltrimethylammonium bromide, water, and sodium hydroxide to a reaction vessel, control the temperature at 70-80℃, stir and react for 1-2 hours, add tetraethyl orthosilicate, keep the reaction at the temperature for 1-2 hours, centrifuge, wash, dry, and calcine to obtain mesoporous silica. A2: In a nitrogen atmosphere, mesoporous silica and anhydrous ethanol are added to a reaction vessel, and the temperature is controlled at 0-5℃. Tetrabutyl titanate is added, and the mixture is kept warm and stirred for 12-15 hours. The temperature is controlled at 100-120℃, and the hydrothermal reaction is carried out for 12-24 hours. The mixture is then centrifuged, washed, dried, and calcined to obtain composite nanoparticles.

3. The preparation method of the high-temperature resistant insulating modified polypropylene cable material according to claim 1, characterized in that, The functional additives include antioxidants and flame retardants; the antioxidants are one or more of antioxidant 1010, antioxidant 2246 or antioxidant 264 mixed in any proportion; the flame retardants are one or more of magnesium hydroxide, aluminum hydroxide or antimony trioxide mixed in any proportion.

4. The preparation method of the high-temperature resistant insulating modified polypropylene cable material according to claim 3, characterized in that, The mass ratio of the antioxidant to the polypropylene resin is 0.5-1:100; The mass ratio of the flame retardant to the polypropylene resin is 2-5:

100.

5. The preparation method of the high-temperature resistant insulating modified polypropylene cable material according to claim 3, characterized in that, The functional additives also include glyceryl stearate; the mass ratio of glyceryl stearate to polypropylene resin is 2-8:

100.

6. High-temperature resistant, insulating modified polypropylene cable material, characterized in that, It is prepared by the preparation method described in any one of claims 1-5.

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