Thermoplastic insulating material, process for its preparation and use

Abstract

The application belongs to the technical field of polymers, and discloses a thermoplastic insulating material, a preparation method and application thereof. The thermoplastic insulating material contains a functional monomer grafted propylene polymer, an optional propylene polymer, an auxiliary agent and an optional elastomer. In the thermoplastic insulating material, the content of the functional monomer structure unit in the grafted state is 0.5-10 wt%, and the content of xylene solubles is 0-70 wt%. The melt flow rate of the thermoplastic insulating material under a load of 2.16 kg at 230 DEG C is 0.2-7 g / 10 min, and the flexural modulus is 150-1600 MPa. The preparation method of the functional monomer grafted propylene polymer comprises: grafting reaction of the propylene polymer and the functional monomer in the presence of an initiator, ultrasonic treatment of the reaction product with ethanol, and filtration and drying. The thermoplastic insulating material has good electrical properties and aging resistance, and can be used stably for a long time under high temperature and high field strength.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, specifically relating to a thermoplastic insulating material, a method for preparing the thermoplastic insulating material, and the application of the thermoplastic insulating material in cables. Background Technology

[0002] To meet the requirements of environmental protection and sustainable development, research on novel recyclable non-crosslinked polyolefin cable insulation materials has become a hot topic in the field of insulation materials. Polypropylene, with its excellent electrical insulation properties and low price, has become the most popular research area.

[0003] To adapt to the application trends of high current carrying capacity and extreme environments in cables, the long-term stable operation of polypropylene insulation materials at high temperatures is particularly crucial. Traditional methods for improving the aging resistance of polyolefins involve adding antioxidants; however, the easy migration of antioxidants affects the long-term anti-aging performance of the material. For example, patent document CN110894320A provides a method to improve the space charge characteristics of polypropylene high-voltage DC cable insulation, thereby enhancing the anti-aging performance of the insulation material. This is achieved by adding free radical scavengers to the polyolefin to introduce charge traps, thus improving the material's anti-aging properties. However, free radical scavengers are prone to migration, making it difficult to maintain stable anti-aging performance. L. Petersson (Electrical Properties of Polypropylene-Bonded Hindered Phenol Blends, IEEE Transactions on Dielectrics and Electrical Insulation Vol.27, No.2; April 2020) proposed a polypropylene-hinded phenol graft to improve the electrical aging performance of polypropylene, but the preparation of this graft is difficult and costly. Therefore, developing a propylene-based thermoplastic insulation material with excellent aging resistance has high practical value. Summary of the Invention

[0004] The purpose of this invention is to provide a thermoplastic insulating material, its preparation method, and its application. This thermoplastic insulating material has good electrical properties and excellent aging resistance, and can be used stably for a long time under high temperature and high field strength.

[0005] A first aspect of the present invention provides a thermoplastic insulating material comprising a functional monomer-grafted modified propylene polymer, optionally a propylene polymer, additives, and optionally an elastomer.

[0006] The thermoplastic insulating material contains 0.5-10 wt% of grafted functional monomer structural units and 0-70 wt% of xylene-soluble substances; the melt flow rate of the thermoplastic insulating material at 230℃ and 2.16 kg load is 0.2-7 g / 10 min; and the flexural modulus of the thermoplastic insulating material is 150-1600 MPa.

[0007] The preparation method of the functional monomer graft-modified propylene polymer includes: a propylene polymer and a functional monomer undergoing a grafting reaction in the presence of an initiator; the reaction product is sonicated with ethanol, then filtered and dried to obtain the functional monomer graft-modified propylene polymer.

[0008] A second aspect of the present invention provides a method for preparing the above-mentioned thermoplastic insulating material, the method comprising: mixing a functional monomer-grafted modified propylene polymer, an optional propylene polymer, an additive, and an optional elastomer, followed by melt extrusion granulation to obtain the thermoplastic insulating material.

[0009] A third aspect of the invention provides the application of the aforementioned thermoplastic insulating material in cables.

[0010] The thermoplastic insulating material of this invention exhibits excellent aging resistance and is suitable for long-term use under high temperature and high field strength conditions. In the preparation of functional monomer-grafted modified propylene polymers, this invention effectively reduces initiator residue and improves the material's aging resistance by incorporating an ethanol ultrasonic step after the propylene polymer grafting reaction.

[0011] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0012] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0013] According to a first aspect of the invention, the invention provides a thermoplastic insulating material comprising a functional monomer-grafted modified propylene polymer, optionally a propylene polymer, additives, and optionally an elastomer.

[0014] The thermoplastic insulating material contains 0.5-10 wt% of grafted functional monomer structural units and 0-70 wt% of xylene-soluble substances; the melt flow rate of the thermoplastic insulating material at 230℃ and 2.16 kg load is 0.2-7 g / 10 min; and the flexural modulus of the thermoplastic insulating material is 150-1600 MPa.

[0015] The preparation method of the functional monomer graft-modified propylene polymer includes: a propylene polymer and a functional monomer undergoing a grafting reaction in the presence of an initiator; the reaction product is sonicated with ethanol, then filtered and dried to obtain the functional monomer graft-modified propylene polymer.

[0016] In a preferred embodiment, the content of grafted functional monomer structural units in the thermoplastic insulating material is 1-8 wt%, preferably 1.5-7 wt%, and the content of xylene-soluble substances is 0.5-65 wt%. The melt flow rate of the thermoplastic insulating material at 230°C and 2.16 kg load is 0.5-5 g / 10 min, preferably 1-3.5 g / 10 min. The flexural modulus of the thermoplastic insulating material is 200-1200 MPa, preferably 400-1000 MPa.

[0017] In this invention, the propylene polymer can be a homogeneous or heterogeneous propylene homopolymer or propylene copolymer, and the content of the copolymer monomer in the propylene polymer is 0-25 wt%, preferably 0-20 wt%. The melt flow rate of the propylene polymer at 230°C and 2.16 kg load is 0.5-10 g / 10 min, preferably 1-7 g / 10 min, and the melting temperature Tm is 110-180°C, preferably 120-170°C.

[0018] According to the present invention, the comonomer of the propylene copolymer may be selected from at least one of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene and 1-octene, preferably ethylene and / or 1-butene.

[0019] In this invention, the functional monomer can be at least one selected from aromatic olefin monomers, siloxane monomers containing unsaturated double bonds, acrylate monomers, acid anhydride monomers, acrylic monomers, and heterocyclic monomers. Preferably, it is an aromatic olefin monomer, such as at least one selected from styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, and 4-methylstyrene, more preferably styrene.

[0020] According to the present invention, the thermoplastic insulating material contains at least one functional monomer grafted modified propylene polymer. That is, the functional monomer grafted modified propylene polymer in the thermoplastic insulating material can be a single functional monomer grafted modified propylene polymer, or it can be a propylene polymer grafted modified with two or more functional monomers.

[0021] The functional monomer-grafted modified propylene polymer of the present invention can be prepared using conventional methods in the prior art, as long as it meets the usage requirements. Preferably, the functional monomer-grafted modified propylene polymer is prepared by the following method:

[0022] a. Place the propylene polymer in a closed reactor and replace it with an inert gas;

[0023] b. Add the free radical initiator and functional monomer to a closed reactor and stir to mix;

[0024] c. Optionally add a swelling aid and optionally cause the reaction system to swell;

[0025] d. Optionally add a dispersant to raise the temperature of the reaction system to the grafting reaction temperature and carry out the grafting reaction;

[0026] e. Optionally filter the reaction product, sonicate it with ethanol, filter and dry it to obtain a functional monomer-grafted modified propylene polymer.

[0027] According to the present invention, the inert gas can be any of the inert gases commonly used in the art, including but not limited to nitrogen and argon.

[0028] In this invention, the free radical initiator is selected from peroxide-based free radical initiators; the peroxide-based free radical initiator is preferably selected from at least one of benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, dodecyl peroxide, tert-butyl peroxide, diisopropyl peroxide, tert-butyl peroxide (2-ethylhexanoate), and dicyclohexyl peroxide.

[0029] Based on the mass of the propylene polymer, the amount of the free radical initiator is 100-1800 ppm, preferably 150-1500 ppm.

[0030] According to the present invention, the amount of the functional monomer is 1-20%, preferably 1.5-16%, and more preferably 2-12%, based on the mass of the propylene polymer.

[0031] According to the present invention, the swelling agent is an organic solvent that has a swelling effect on olefin polymers, and the swelling agent is preferably selected from at least one of benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, diethyl ether, acetone, hexane, cyclohexane, decahydronaphthalene, and heptane. Based on the mass of the propylene polymer, the amount of the swelling agent is 1-30%, preferably 10-25%.

[0032] In this invention, the swelling conditions include: the swelling temperature can be 30-60℃, and the time can be 1-5 hours.

[0033] The dispersant is water or an aqueous solution of sodium chloride. The water is deionized water, and the aqueous solution of sodium chloride can be of any conventionally used concentration. Based on the mass of the propylene polymer, the amount of the dispersant is 50-300%.

[0034] In this invention, the temperature of the grafting reaction is 80-130℃, preferably 85-120℃; the time is 0.5-10 hours, preferably 1-6 hours.

[0035] According to the present invention, all materials in the grafting reaction system can be added at once or at different stages of the reaction.

[0036] In this invention, ethanol is used to sonicate the reaction product. Ethanol acts as a free radical terminator and dissolves most of the initiator residues and unreacted graft monomers. Ultrasound allows for rapid and thorough penetration into the material, effectively reducing components that easily cause material degradation, improving the purity of the modified material, and thus enhancing the anti-aging properties of the final product. Used ethanol can be recovered and reused via vacuum distillation. The amount of ethanol used is 0.5-3 times the mass of the reaction product, preferably 1-2 times; the ultrasonic treatment time is 2-10 minutes, preferably 5-8 minutes.

[0037] According to the present invention, the additive contains an antioxidant, optional processing aids, and optional copper inhibitors.

[0038] The antioxidant is selected from at least one of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, and thiolated antioxidants. The antioxidant is preferably pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 2,4,6-tris(3′,5′-di-tert-butyl-4′-hydroxybenzyl)trimethylbenzene, N,N′-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,2′-thiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2 At least one of the following: ′,2-oxamido-bis-[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4′-thiobis(6-tert-butyl-3-methylphenol), triphenyl phosphite, tris[2,4-di-tert-butylphenyl]phosphite, and dilauryl thiodipropionate.

[0039] The processing aid is selected from at least one of fluorinated compounds, polypropylene wax, polyethylene wax, fatty acid esters and mineral oil, preferably at least one of polypropylene wax, fatty acid esters and mineral oil.

[0040] The copper-resistant agent may be at least one of N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,2-oxamido-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionic acid, and N-salicylamidophthalimide.

[0041] In this invention, the elastomer is preferably selected from at least one of POE, PBE, EPR, EPDM, SEBS and SBS.

[0042] According to a second aspect of the present invention, the present invention provides a method for preparing the above-mentioned thermoplastic insulating material, the method comprising: mixing a functional monomer-grafted modified propylene polymer, optionally a propylene polymer, an additive and optionally an elastomer, and melt-extruding and granulating to obtain the thermoplastic insulating material.

[0043] According to the present invention, the additive contains an antioxidant, optional processing aids, and optional copper inhibitors. Based on the total mass of the functional monomer-grafted modified propylene polymer, the propylene polymer, and the elastomer, the amount of the functional monomer-grafted modified propylene polymer is 50% or more, preferably greater than 55%, more preferably greater than 60%; the amount of the antioxidant is greater than 2000 ppm, preferably 3000-5000 ppm; when processing aids are included, the amount of processing aids is 0.3-4%, preferably 0.5-2%; when copper inhibitors are included, the amount of copper inhibitors is 1000-5000 ppm, preferably 1500-4000 ppm.

[0044] In addition, depending on the product requirements, other additives may be added to this invention, such as voltage stabilizers, antioxidants, etc. The types and amounts of other additives are conventional and known to those skilled in the art.

[0045] In this invention, melt extrusion granulation can be carried out using conventional equipment in the prior art, preferably a twin-screw extruder. The temperature of the melt extrusion granulation can be 180-250℃, preferably 185-230℃, and more preferably 190-220℃.

[0046] A third aspect of the invention provides the application of the aforementioned thermoplastic insulating material in cables.

[0047] The thermoplastic insulating material of the present invention can be used as an insulating material in the field of cables, and the specific usage can be referred to conventional insulating materials.

[0048] The substances and parameters not limited in this invention can be selected according to existing technology, which is a conventional technical means in this field.

[0049] The present invention will be further described below with reference to embodiments. However, the invention is not limited to these embodiments.

[0050] In the following preparation examples, embodiments, and comparative examples, the data were obtained using the following test methods:

[0051] 1. Determination of comonomer content in propylene polymers:

[0052] The content of comonomers was determined by quantitative Fourier transform infrared (FTIR) spectroscopy. The correlation of the determined comonomer content was calibrated by quantitative nuclear magnetic resonance (NMR) spectroscopy. Based on quantitative... 13 The calibration method for the C-NMR spectrometer results was performed according to conventional methods in the art.

[0053] 2. Determination of xylene-soluble content (XS):

[0054] The test shall be conducted according to the method specified in GB / T 24282-2009.

[0055] 3. Grafting rate (GD) (n) / GD determination:

[0056] Place 2-4g of the grafted product into a Soxhlet extractor and extract with an organic solvent (ethyl acetate for aromatic olefin monomers, acrylate monomers, and acid anhydrides; acetone for silane monomers) for 24 hours to remove unreacted monomers and their homopolymers, obtaining a pure grafted product. Dry the product, weigh it, and calculate the grafting rate. GD (n) GD represents the grafting rate of the propylene polymer grafted with functional monomers in the material. GD represents the content of functional monomers in the grafted structural units of the thermoplastic insulating material. In this invention, the formula for calculating GD is as follows:

[0057]

[0058]

[0059] In the above formulas, w0 is the mass of the propylene polymer; w1 is the mass of the grafted product before extraction; and w2 is the mass of the grafted product after extraction. When the thermoplastic insulating material contains more than one graft, m... n1 It is the mass of the propylene polymer modified by the first functional monomer in the material, m n2 This refers to the mass of the propylene polymer modified by the second functional monomer, and so on; m 产品 It refers to the quality of thermoplastic insulating materials.

[0060] 4. Determination of melt flow rate (melt index) MFR:

[0061] The test was performed using a CEAST 7026 melt flow indexer at 230°C and a load of 2.16 kg, according to the method specified in GB / T 3682-2018.

[0062] 5. Determination of melting temperature (melting point) Tm:

[0063] Differential scanning calorimetry (DSC) was used to analyze the melting and crystallization processes of the material. Specifically, under nitrogen protection, 5-10 mg of sample was heated from 20°C to 200°C using a three-stage temperature rise and fall measurement method. The change in heat flow reflected the melting and crystallization processes, and the melting temperature Tm was calculated.

[0064] 6. Methods for aging test samples

[0065] The determination shall be performed in accordance with the method specified in GB / T 2951.2.

[0066] 7. Determination of DC volume resistivity:

[0067] The determination shall be carried out in accordance with the method specified in GB / T 1410-2006.

[0068] 8. Determination of breakdown field strength:

[0069] The determination shall be carried out in accordance with the method specified in GB / T 1408-2006.

[0070] 9. Determination of tensile strength and elongation at break:

[0071] The determination shall be carried out in accordance with the method specified in GB / T 1040.2-2006.

[0072] 10. Determination of flexural modulus:

[0073] The determination shall be carried out in accordance with the method specified in GB / T 9341-2008.

[0074] The reagents used in the preparation examples, embodiments, and comparative examples are as follows:

[0075] Benzoyl peroxide (BPO), Bailingwei Technology Co., Ltd.;

[0076] Lauroyl peroxide (LPO), Bailingwei Technology Co., Ltd.;

[0077] tert-butyl peroxide (2-ethylhexanoate), Adamas Reagents Ltd.

[0078] Styrene (St), Bailingwei Technology Co., Ltd.;

[0079] Methyl methacrylate (MMA), Bailingwei Technology Co., Ltd.

[0080] Xylene, Bailingwei Technology Co., Ltd.;

[0081] Antioxidants: Antioxidant 1035, Antioxidant 1010, Antioxidant 168, Antioxidant 697, Shanghai Kaiyin Chemical Co., Ltd.

[0082] Processing aids (lubricants): PP wax 2602 (Clariant), PPA 5920A (3M, USA);

[0083] Copper inhibitors: MD-1024, MDA-5, Shanghai Kaiyin Chemical Co., Ltd.

[0084] Elastomers: Vistamaxx 6102, Vistamaxx 6202, ExxonMobil;

[0085] Propylene polymers are shown in Table 1:

[0086] Table 1

[0087]

[0088] Preparation Examples 1-5

[0089] Weigh the propylene polymer powder and add it to a reaction vessel equipped with a mechanical stirrer. Seal the reaction system and remove oxygen by nitrogen purging. Add the mixture of initiator and functional monomer, and stir and mix with the powder for 15-20 minutes. Optionally, add a dispersant or swelling aid. Optionally, raise the temperature and allow it to swell. Then raise the temperature to the reaction temperature and react for 3-6 hours. After the reaction is complete, cool down and optionally filter to remove the dispersant and water. Sonicate in ethanol at room temperature for 2-10 minutes and dry at 70°C for 4 hours to obtain the functional monomer grafted modified propylene polymer (modified powder). The detailed reaction conditions and product properties are shown in Tables 2 and 3, by mass fraction.

[0090] Comparative preparation examples 1-2

[0091] The difference between Comparative Preparation Example 1 and Preparation Example 1 is that the amount of initiator used is 0.20 parts by weight; all other aspects are the same. The difference between Comparative Preparation Example 2 and Preparation Example 1 is that the product was not treated with ethanol; all other aspects are the same. Detailed reaction conditions and product properties are shown in Tables 2 and 3.

[0092] Table 2

[0093]

[0094] Table 3

[0095]

[0096] Examples 1-5

[0097] Weigh the modified powder, antioxidant, processing aid, copper inhibitor, optional propylene polymer, optional elastomer, etc. The amount of each material is expressed as parts by mass, percentage by mass, or ppm by mass. After mixing thoroughly with a high-speed mixer, add to a twin-screw extruder and melt extrude and granulate to obtain a thermoplastic insulating material. Specific conditions and material properties are shown in Tables 4 and 5.

[0098] Comparative Examples 1-4

[0099] The difference between Comparative Example 1 and Example 1 is that the modified polypropylene powder used in Comparative Example 1 was prepared from Comparative Preparation Example 1; otherwise, they are the same. The difference between Comparative Example 2 and Example 1 is that the unmodified propylene polymer was used instead of the modified propylene polymer in Example 1; otherwise, they are the same. The difference between Comparative Example 3 and Example 1 is that the amount of antioxidant used is different; otherwise, they are the same. The difference between Comparative Example 4 and Example 1 is that the modified polypropylene powder used was prepared from Comparative Preparation Example 2; otherwise, they are the same. Specific preparation conditions and material properties are shown in Tables 4 and 5, respectively.

[0100] Table 4

[0101]

[0102] Table 5

[0103]

[0104] The materials prepared in the examples and comparative examples were aged, and the properties of the materials before and after aging are shown in Table 6.

[0105] Table 6

[0106]

[0107] Comparing the data from Example 1 and Comparative Example 1 shows that excessive initiator dosage and excessive residual initiator lead to a decrease in the electrical and mechanical properties of the product after aging. Comparing the data from Example 1 and Comparative Example 2 shows that using ungrafted modified propylene polymer results in a significant decrease in the electrical properties of the product after aging. Comparing the data from Example 1 and Comparative Example 3 shows that insufficient antioxidant dosage leads to a decrease in the electrical and mechanical properties of the product after aging. Comparing the data from Example 1 and Comparative Example 4 shows that the product was not treated with ethanol, resulting in excessive residual initiator, which leads to a decrease in the electrical and mechanical properties of the product after aging.

[0108] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A thermoplastic insulating material, characterized in that, The thermoplastic insulating material contains a functional monomer grafted propylene polymer, optionally a propylene polymer, an auxiliary agent, and optionally an elastomer; The content of the functional monomer structure unit in the grafted state in the thermoplastic insulating material is 0.5-10wt%, the content of the xylene soluble is 0-70wt%; the melt flow rate of the thermoplastic insulating material under a load of 2.16 kg at 230℃ is 0.2-7g / 10min; the bending modulus of the thermoplastic insulating material is 150-1600MPa; The preparation method of the functional monomer grafted propylene polymer includes: grafting reaction of the propylene polymer and the functional monomer in the presence of an initiator, ultrasonic treatment of the reaction product with ethanol, and then filtration and drying to obtain the functional monomer grafted propylene polymer; the amount of ethanol is 0.5-3 times the mass of the reaction product; the ultrasonic treatment time is 2-10 minutes; the amount of the initiator is 100-1800ppm based on the mass of the propylene polymer; The propylene polymer is a propylene homopolymer or a propylene copolymer, and the content of the comonomer in the propylene polymer is 0-25wt%; the melt flow rate of the propylene polymer under a load of 2.16 kg at 230℃ is 0.5-10g / 10min, and the melting temperature Tm is 110-180℃; The functional monomer is an aromatic olefin monomer and / or an acrylic ester monomer; The auxiliary agent contains an antioxidant, optionally a processing aid, and optionally a copper inhibitor; the amount of the functional monomer grafted propylene polymer is more than 50% based on the total mass of the functional monomer grafted propylene polymer, the propylene polymer, and the elastomer; the amount of the antioxidant is greater than 2000ppm; the amount of the processing aid is 0.3-4%; and the amount of the copper inhibitor is 1000-5000ppm.

2. The thermoplastic insulating material of claim 1, wherein, The content of the functional monomer structure unit in the grafted state in the thermoplastic insulating material is 1-8wt%, and the content of the xylene soluble is 0.5-65wt%; the melt flow rate of the thermoplastic insulating material under a load of 2.16 kg at 230℃ is 0.5-5g / 10min; and the bending modulus of the thermoplastic insulating material is 200-1200MPa.

3. The thermoplastic insulating material of claim 2, wherein, The content of the functional monomer structure unit in the grafted state in the thermoplastic insulating material is 1.5-7wt%; the melt flow rate of the thermoplastic insulating material under a load of 2.16 kg at 230℃ is 1-3.5g / 10min; and the bending modulus of the thermoplastic insulating material is 400-1000MPa.

4. The thermoplastic insulating material of claim 1, wherein, The content of the comonomer in the propylene polymer is 0-20wt%.

5. The thermoplastic insulating material of claim 1, wherein, The melt flow rate of the propylene polymer under a load of 2.16 kg at 230℃ is 1-7g / 10min, and the melting temperature Tm is 120-170℃.

6. The thermoplastic insulating material of claim 1, wherein, The comonomer of the propylene copolymer is at least one selected from the group consisting of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene.

7. The thermoplastic insulating material of claim 6, wherein, The comonomer of the propylene copolymer is ethylene and / or 1-butene.

8. The thermoplastic insulating material of claim 1, wherein, The functional monomer is styrene.

9. The thermoplastic insulating material according to any one of claims 1-8, wherein, The thermoplastic insulating material contains at least one functional monomer grafted propylene polymer.

10. The thermoplastic insulating material of claim 9, wherein, The functional monomer grafted propylene polymer is prepared by the following method: a. Put the propylene polymer into a closed reactor and replace with inert gas; b. Add the free radical initiator and the functional monomer into the closed reactor and mix by stirring; c. Optionally add the co-swelling agent and optionally swell the reaction system; d. Optionally add the dispersant, heat the reaction system to the grafting reaction temperature and conduct the grafting reaction; e. Optionally filter, ultrasonic the reaction product with ethanol, filter and dry to obtain the functional monomer grafted propylene polymer.

11. The thermoplastic insulating material of claim 10, wherein, The free radical initiator is selected from peroxide free radical initiators; The amount of the functional monomer is 1-20% based on the mass of the propylene polymer.

12. The thermoplastic insulating material of claim 11, wherein, The peroxide free radical initiator is selected from at least one of dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, dodecanoyl peroxide, t-butyl perbenzoate, diisopropyl peroxydicarbonate, t-butyl peroxy(2-ethylhexanoate) and dicyclohexyl peroxydicarbonate.

13. The thermoplastic insulating material of claim 12, wherein, The amount of the functional monomer is 1.5-16% based on the mass of the propylene polymer.

14. The thermoplastic insulating material of claim 13, wherein, The amount of the functional monomer is 2-12% based on the mass of the propylene polymer.

15. The thermoplastic insulating material of claim 12, wherein, The amount of the free radical initiator is 150-1500 ppm based on the mass of the propylene polymer.

16. The thermoplastic insulating material of claim 10, wherein, The co-swelling agent is selected from at least one of benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, diethyl ether, acetone, hexane, cyclohexane, decalin and heptane; the amount of the co-swelling agent is 1-30% based on the mass of the propylene polymer; The swelling temperature is 30-60℃ and the time is 1-5 hours; The dispersant is water or an aqueous sodium chloride solution; the amount of the dispersant is 50-300% based on the mass of the propylene polymer; The grafting reaction temperature is 80-130℃ and the time is 0.5-10 hours; The amount of ethanol is 1-2 times the mass of the reaction product and the ultrasonic time is 5-8 minutes.

17. The thermoplastic insulating material of claim 16, wherein, The amount of the co-swelling agent is 10-25% based on the mass of the propylene polymer.

18. The thermoplastic insulating material of claim 16, wherein, The grafting reaction temperature is 85-120℃ and the time is 1-6 hours.

19. The thermoplastic insulating material of claim 1, wherein, The auxiliary agent contains an antioxidant, an optional processing aid and an optional copper inhibitor; The antioxidant is selected from at least one of hindered phenol antioxidants, hindered amine antioxidants, phosphite antioxidants and thio antioxidants; The processing aid is selected from at least one of fluorine-containing compounds, polypropylene wax, polyethylene wax, fatty acid esters and mineral oil.

20. The thermoplastic insulating material of claim 19, wherein, The antioxidant is at least one of tetrakis [beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, 2, 2'-methylenebis (4-methyl-6-tert-butylphenol), 2, 4, 6-tris (3', 5'-di-tert-butyl-4'-hydroxybenzyl) mesitylene, N, N'-bis [beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2, 2'-thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid], 2', 2-oxamidyl-bis- [ethyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate], n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, 1, 1, 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4, 4'-thiobis (6-tert-butyl-3-methylphenol), triphenyl phosphite, tris [2, 4-di-tert-butylphenyl] phosphite, dilauryl thiodipropionate.

21. The thermoplastic insulating material of claim 19, wherein, The processing aid is at least one of polypropylene wax, fatty acid ester and mineral oil.

22. The thermoplastic insulating material of claim 19, wherein, The anti-copper agent is at least one of N, N'-bis [beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2, 2-oxamidyl-bis [ethyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate] and N-salicyloylaminophthalimide.

23. The thermoplastic insulating material of claim 19, wherein, The elastomer is at least one of POE, PBE, EPR, EPDM, SEBS and SBS.

24. A process for the production of a thermoplastic insulating material according to any one of claims 1 to 23, characterized in that, The preparation method comprises: mixing the functional monomer grafted modified propylene polymer, optional propylene polymer, aid and optional elastomer, melt extruding and granulating to obtain the thermoplastic insulating material.

25. The method of producing a thermoplastic insulating material according to claim 24, wherein, The temperature of the melt extruding and granulating is 180-250 DEG C.

26. The method of claim 24, wherein the thermoplastic insulation material is prepared by The amount of the functional monomer grafted modified propylene polymer is greater than 55% based on the total mass of the functional monomer grafted modified propylene polymer, propylene polymer and elastomer.

27. The method of producing a thermoplastic insulating material according to claim 26, wherein, The amount of the functional monomer grafted modified propylene polymer is greater than 60% based on the total mass of the functional monomer grafted modified propylene polymer, propylene polymer and elastomer.

28. The method of producing a thermoplastic insulating material according to claim 24, wherein, The amount of the antioxidant is 3000-5000 ppm.

29. The method of producing a thermoplastic insulating material according to claim 24, wherein, The amount of the processing aid is 0.5-2%.

30. The method of producing a thermoplastic insulating material according to claim 24, wherein, The amount of the anti-copper agent is 1500-4000 ppm.

31. The method of producing a thermoplastic insulating material according to claim 25, wherein, The temperature of the melt extruding and granulating is 185-230 DEG C.

32. The method of producing a thermoplastic insulating material according to claim 31, wherein, The temperature of the melt extruding and granulating is 190-220 DEG C.

33. The use of the thermoplastic insulating material of any one of claims 1-23 or the thermoplastic insulating material prepared by the preparation method of any one of claims 24-32 in a cable.

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