Polyolefin composite material as well as preparation method and application thereof

Abstract

The invention provides a polyolefin composite material as well as a preparation method and application thereof. The material comprises the following raw materials in parts by weight: 100 parts of a polyolefin elastomer, 2-5 parts of a compatibilizer, 0.5-3 parts of an antioxidant and 4-11 parts of a rheological additive, the high-temperature-resistant flame-retardant ceramic material is prepared from the following components in parts by weight: 60-100 parts of a flame retardant, 40-80 parts of a framework filler and a ceramic forming filler, 10-50 parts of a silicon source and 1-10 parts of a nucleating aid. The composite material can realize ceramization of polyolefin through a flux-free system.

Description

Technical Field

[0001] This invention relates to the field of composite materials technology, and more specifically, to a polyolefin composite material, its preparation method, and its application. Background Technology

[0002] With societal development, the performance requirements for cables are becoming increasingly stringent, especially in terms of fire safety. Traditional cable materials are prone to combustion in fire situations, releasing large amounts of heat and toxic gases, failing to meet the stringent fire resistance requirements of modern buildings and industrial sites. Ceramicized polyolefin materials, as a new type of fire-resistant material, can form a hard, ceramic-like outer shell at high temperatures, effectively isolating flames and heat, protecting the internal structure of the cable, and ensuring a certain period of energization in a fire, providing opportunities for escape and braking, thus possessing broad application prospects. Common ceramicized polyolefin materials typically require the addition of fluxes, such as zinc borate or low-melting-point glass powder, to lower the ceramicization temperature and promote the ceramicization process.

[0003] CN119286098A discloses a ceramicized polyolefin, its preparation method, and its application. The raw materials for preparation include: 40-60 parts of polyolefin resin, wherein the polyolefin resin is a mixture of polyethylene and ethylene-octene copolymer; 40-60 parts of ceramicizing powder, wherein the ceramicizing powder is a mixture of silicon dioxide, boron oxide, zinc oxide, and magnesium oxide; 20-40 parts of low-melting-point glass powder, wherein the melting point of the low-melting-point glass powder is 400-600℃; 15-60 parts of silicate filler; and 0.1-3 parts of antioxidant. The ceramicized polyolefin provided exhibits excellent tensile strength and elongation at break, and the ceramic shell remains intact. However, this technology involves the use of low-temperature glass powder.

[0004] CN118755177A provides an EVA-based ceramicized polyolefin cable sheath. The raw materials used in this cable sheath include the following components by weight: 75-85 parts base material, 20-20.8 parts microencapsulated IFR, 2-3 parts OMMT, 0.8-1.2 parts Zn / TiO2@acidified kaolin, 15-20 parts glass powder, 110-120 parts ceramic powder, 7-10 parts POE-g-GMA, 1-3 parts antioxidant, and 2-5 parts lubricant. However, this technology uses microencapsulated flame retardants and low-temperature glass powder. Additionally, this technology uses co-solvents such as zinc borate and ammonium polyphosphate, requiring a relatively high ceramicization temperature (800℃).

[0005] CN117070016A provides a high-temperature resistant, fire-resistant, ceramicized polyolefin material, comprising the following raw materials in parts by weight: 25-30 parts of polyethylene elastomer; 4-8 parts of metallocene linear polyethylene; 5-8 parts of metallocene polyethylene graft compatibilizer; 35-40 parts of mixed ceramic powder; 7-10 parts of flame retardant; 5-8 parts of low-temperature glass powder; 0.4-0.8 parts of coupling agent; 2-3 parts of lubricant; and 2-3 parts of antioxidant. The polyethylene elastomer has a tensile strength ≥25 MPa and an elongation at break ≥800%. However, this technology also involves the use of low-temperature glass powder.

[0006] In these existing technologies, the presence of flux often reduces the mechanical strength of the material and makes it prone to melting and dripping at high temperatures, affecting its thermal insulation and fire resistance. Furthermore, the presence of alkali metal elements may affect flame retardant properties. Summary of the Invention

[0007] To address the problems in the prior art described above, the present invention aims to provide a polyolefin composite material, its preparation method, and its applications. This composite material can achieve ceramicized polyolefins through a flux-free system.

[0008] According to a first aspect of the present invention, a polyolefin composite material is provided, wherein the polyolefin composite material comprises the following raw materials in parts by weight: 100 parts by weight of polyolefin elastomer, 2-5 parts by weight of compatibilizer, 0.5-3 parts by weight of antioxidant, 4-11 parts by weight of rheology modifier; 60-100 parts by weight of flame retardant, 40-80 parts by weight of skeleton filler, ceramic filler, 10-50 parts by weight of silicon source, and 1-10 parts by weight of nucleating agent;

[0009] The polyolefin elastomer includes one or a combination of two of EVA and POE.

[0010] The flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, and magnesium aluminum hydrotalcite.

[0011] The ceramic filler comprises 10-30 parts by weight of montmorillonite and 5-20 parts by weight of organically modified montmorillonite;

[0012] The nucleating agent includes montmorillonite and an active component supported on the montmorillonite, wherein the active component includes one or more of transition metal oxides and phosphates.

[0013] When the material is subjected to high temperature or during its combustion, the nucleating agent simultaneously induces the transformation of the polyolefin carbon skeleton of the present invention into a continuous Si-O-Al ceramic network during the pyrolysis stage, and eutecticly crystallizes with the hydroxide decomposition products (alumina, magnesium oxide; it should be noted that at least one of Mg or Al is required) in situ to form a dense, non-porous ceramic shell; this process can achieve low-temperature densification without the need for a low-melting-point liquid phase, so the polyolefin composite material of the present invention has both high mechanical strength and high-temperature ablation resistance.

[0014] Specifically, when heated or burned:

[0015] Nucleating agents catalyze the early carbonization of polyolefin segments, forming a three-dimensional carbon network;

[0016] The hydroxide dehydrates to form aluminum oxide and magnesium oxide;

[0017] Silicon source is cracked to form active silicon dioxide;

[0018] The aforementioned three-dimensional carbon network, silicon dioxide, aluminum oxide, magnesium oxide, and montmorillonite react to form a low-temperature eutectic liquid phase, resulting in a ceramic body with a porous heat-insulating structure.

[0019] As the temperature continues to rise, the eutectic phase crystallizes to form high-melting-point mullite and cristobalite, and the ceramic body becomes denser.

[0020] Because it lacks a low-melting-point glass phase, the ceramic body still maintains high viscosity at temperatures ≥1200℃ and does not melt and drip.

[0021] In the various raw materials of this invention, the polyolefin elastomer provides matrix flexibility, extrudability, and initial mechanical strength. Compatibilizers are used to improve the interfacial compatibility between polar fillers and polyolefins, preventing phase separation. Antioxidants are used to inhibit thermo-oxidative degradation during processing and service. Rheology modifiers are used to adjust melt flowability, reduce screw torque, and improve extrusion efficiency. Flame retardants are used for low-temperature endothermic dehydration to inhibit combustion; and their dehydration products act as a ceramic skeleton, reacting with the silicon source to form a eutectic phase. Skeletal fillers are used to provide high-temperature skeletal support, reducing ceramic shrinkage and cracking. Ceramic-forming fillers are used to promote densification, reacting with the silicon source and metal oxides to form a mullite / cordierite phase, improving ceramic strength. The silicon source is pyrolyzed to generate a silica glass phase, forming a continuous ceramic network with the metal oxide. Nucleating agents are used to induce early carbonization of polyolefins, forming a carbon skeleton, and promoting low-temperature eutectic formation of silica with alumina / magnesia, lowering the ceramic-forming initiation temperature while increasing high-temperature viscosity to prevent melt flow.

[0022] In some preferred embodiments of the present invention, the transition metal oxide includes one or a combination of two of iron oxide, nickel oxide, zinc oxide, and titanium oxide.

[0023] In some preferred embodiments of the present invention, the polyolefin elastomer comprises 10-40 parts by weight of EVA, 10-40 parts by weight of POE, 10-40 parts by weight of ternary copolymer polyethylene, and 10-40 parts by weight of metallocene polyethylene. The above-mentioned preferred components and proportions are more conducive to providing the matrix with good toughness, extrudability, and initial mechanical strength.

[0024] In some preferred embodiments of the present invention, the active component accounts for 0.1% to 10% by weight in the nucleating agent.

[0025] In some preferred embodiments of the present invention, the preparation method of the nucleating agent includes: mixing the active component precursor and montmorillonite, and heat-treating at 500~1200℃ to obtain the agent; wherein the active component precursor includes one or more of ferric chloride, nickel chloride, cobalt chloride, zinc acetate, titanate, and calcium phosphate.

[0026] In some preferred embodiments of the present invention, the compatibilizer includes one or more of maleic anhydride-grafted polyethylene, acrylic acid-grafted polyolefin, and silane coupling agents.

[0027] In some preferred embodiments of the present invention, the organically modified montmorillonite includes one or a combination of two or more of the following: high-purity organomontmorillonite DK4 modified with long-chain alkylammonium and high-purity organomontmorillonite DK18 modified with long-chain alkylammonium.

[0028] In some preferred embodiments of the present invention, the antioxidant includes one or more of antioxidant 1010, antioxidant 1098, antioxidant 1076, antioxidant DLTP, antioxidant DSDTP, antioxidant 168, and antioxidant 626.

[0029] In some preferred embodiments of the present invention, the ceramic filler further includes one or a combination of two of bentonite and kaolin.

[0030] In some preferred embodiments of the present invention, when the magnesium hydroxide is used alone in the flame retardant, the mass ratio of the polyolefin to the magnesium hydroxide is 1:1 to 1:2;

[0031] When the aluminum hydroxide is used alone, the mass ratio of the polyolefin to the aluminum hydroxide is 1:1 to 1:2;

[0032] When using the aluminum hydroxide, the magnesium hydroxide, and the magnesium-aluminum hydrotalcite, the mass ratio of the polyolefin, the aluminum hydroxide, the magnesium hydroxide, and the magnesium-aluminum hydrotalcite is 1:0.4:0.6:0.1 to 1:0.8:1.2:1.

[0033] In some preferred embodiments of the present invention, the skeleton filler includes one or more of acicular wollastonite, sepiolite, and glass fiber.

[0034] In some preferred embodiments of the present invention, the silicon source includes one or a combination of two or more of silicone rubber, silicone resin, and silane coupling agent modified silica. Preferably, the silicone resin includes one or a combination of two of methylphenyl silicone resin and MQ silicone resin.

[0035] In some preferred embodiments of the present invention, the rheology modifier comprises 3 to 6 parts by weight of silicone masterbatch and 1 to 5 parts by weight of polyethylene wax.

[0036] According to another aspect of the present invention, a method for preparing the above-mentioned polyolefin composite material is also provided, comprising:

[0037] S1, the polyolefin elastomer, compatibilizer, antioxidant, rheology modifier, flame retardant, skeleton filler, ceramic filler, silicon source, and nucleating agent are blended at a blending temperature of 60~80℃ and a blending time of 10~20min, with a stirring speed of 5~50rpm to obtain the mixture.

[0038] S2, the mixture is processed and shaped at a temperature of 140~170℃ to obtain the polyolefin composite material.

[0039] In some preferred embodiments of the present invention, the processing and molding method includes twin-screw extrusion, internal mixing-single-screw extrusion, and continuous internal mixing-hot cutting pelletizing.

[0040] In some preferred embodiments of the present invention, the temperature during extrusion in the twin-screw extruder is controlled as follows: Zone 1 140~145℃, Zone 2 145~150℃, Zone 3 150~155℃, Zone 4 155~160℃, Zone 5 160~165℃, Zone 6 165~170℃, Zone 7 160~165℃, Zone 8 155~160℃; and the die head 140~150℃.

[0041] In some preferred embodiments of the present invention, the preparation method further includes: drying the polyolefin composite material until the water content is ≤1wt%.

[0042] In some preferred embodiments of the present invention, the application of the polyolefin composite material as a cable material is also provided.

[0043] Compared with the existing technologies that generally rely on fluxes such as zinc borate and low-melting-point glass powder to reduce the ceramic forming temperature and promote ceramicization, this invention creatively proposes a "flux-free" system: in the polyolefin elastomer matrix, through the synergistic reaction of "nucleating agent-silicon source-hydroxide-ceramic filler", a dense ceramic shell is generated in situ when heated or burned, and the ceramic body remains non-melting and non-collapsed at high temperatures.

[0044] The polyolefin composite material of the present invention has both high mechanical strength and good resistance to high temperature ablation. Attached Figure Description

[0045] Figure 1 SEM images of the ceramic body after ablation of the polyolefin composite material in Example 1 are shown.

[0046] Figure 2 SEM images of the ceramic body after ablation of the polyolefin composite material in Example 1 are shown. Detailed Implementation

[0047] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0048] Example 1

[0049] A polyolefin composite material, comprising the following parts by weight of raw materials:

[0050] 100 parts of polyolefin elastomer, including 20 parts of EVA (7470, Formosa Plastics, Taiwan, China), 30 parts of POE (C1070D, Basic Innovation Plastics, South Korea), 30 parts of low-density polyethylene LLDPE (LX-1010, Tianjin Petrochemical, China) and 20 parts of metallocene polyethylene mPE (XP8784ML, ExxonMobil, USA);

[0051] Compatibilizer: 3 parts maleic anhydride-grafted polyethylene;

[0052] One part of antioxidant, including 0.5 parts each of antioxidant 1010 and antioxidant DLTP;

[0053] Eight parts of rheology modifier, including four parts of silicone masterbatch and four parts of polyethylene wax;

[0054] Flame retardant 80 parts, including 60 parts aluminum hydroxide and 20 parts magnesium hydroxide;

[0055] 60 parts of acicular wollastonite as a skeleton filler;

[0056] 30 parts of ceramic filler, including 15 parts of montmorillonite and 15 parts of organically modified montmorillonite (high-purity organic montmorillonite DK4 modified with double long-chain alkylammonium);

[0057] 30 parts of silicon source, which is silicone rubber;

[0058] Five parts of nucleating agent were used, and titanium dioxide was loaded onto montmorillonite. The mass percentage of the active ingredient, titanium dioxide, was 5%.

[0059] Its preparation method is as follows:

[0060] S0, preparation of nucleating agent: 10 parts by mass of titanate precursor and 100 parts by mass of montmorillonite are mixed and heat-treated at 800℃ to obtain nucleating agent;

[0061] S1. Weigh each raw material according to the weight parts, add them to a high-speed mixer, mix at 70℃ for 15 minutes at 10rpm, so that each raw material is fully mixed and uniform to obtain a mixture.

[0062] S2, the mixture is added to a twin-screw extruder and granulated by extrusion to obtain the flux-free ceramicized polyolefin cable material. The temperature settings of the twin-screw extruder are: Zone 1 140℃, Zone 2 150℃, Zone 3 160℃, Zone 4 160℃, Zone 5 150℃, Zone 6 140℃, Zone 7 140℃, Zone 8 130℃, and the die head temperature is 130℃.

[0063] Figure 1 SEM images of the ceramic body after ablation of the polyolefin composite material in Example 1 are shown.

[0064] Figure 2 SEM images of the ceramic body after ablation of the polyolefin composite material in Example 1 are shown.

[0065] Depend on Figure 1 , Figure 2 As can be seen, a eutectic phase and a porous structure have formed in the material.

[0066] Example 2

[0067] A polyolefin composite material, comprising the following parts by weight of raw materials:

[0068] 100 parts of polyolefin elastomer, including 30 parts of EVA, 25 parts of POE, 25 parts of low-density polyethylene LLDPE (LX-1010), and 20 parts of metallocene polyethylene mPE (XP8784ML).

[0069] Compatibilizer: 4 parts maleic anhydride-grafted polyethylene;

[0070] One part of antioxidant, including 0.5 parts each of antioxidant 1010 and antioxidant DLTP;

[0071] 10 parts of rheology modifier, including 5 parts of silicone masterbatch and 5 parts of polyethylene wax;

[0072] 90 parts of flame retardant, including 70 parts of aluminum hydroxide and 20 parts of magnesium hydroxide;

[0073] 70 parts of acicular wollastonite as a skeleton filler;

[0074] 35 parts of ceramic filler, including 20 parts of montmorillonite and 15 parts of organically modified montmorillonite (high-purity organic montmorillonite DK4 modified with double long-chain alkylammonium);

[0075] 40 parts of silicon source, which is silicone resin (methyl MQ silicone resin, MQ ratio 0.8, white powder);

[0076] Eight parts of nucleating agent were prepared by loading nickel oxide onto montmorillonite, wherein the mass content of nickel oxide was 8%. The preparation method of the nucleating agent was as follows: 14.2 parts of anhydrous nickel chloride and 100 parts of montmorillonite were mixed and heat-treated at 800℃ to obtain the nucleating agent.

[0077] Other preparation methods are the same as in Example 1.

[0078] Comparative Example 1

[0079] A polyolefin composite material, comprising the following parts by weight of raw materials:

[0080] 100 parts of polyolefin elastomer, including 30 parts of EVA, 25 parts of POE, 25 parts of low-density polyethylene LLDPE (LX-1010), and 20 parts of metallocene polyethylene mPE (XP8784ML).

[0081] Compatibilizer: 4 parts maleic anhydride-grafted polyethylene;

[0082] One part of antioxidant, including 0.5 parts each of antioxidant 1010 and antioxidant DLTP;

[0083] 10 parts of rheology modifier, including 5 parts of silicone masterbatch and 5 parts of polyethylene wax;

[0084] 90 parts of flame retardant, including 70 parts of aluminum hydroxide and 20 parts of magnesium hydroxide;

[0085] 70 parts of acicular wollastonite as a skeleton filler;

[0086] 35 parts of ceramic filler, including 20 parts of montmorillonite and 15 parts of organically modified montmorillonite (high-purity organic montmorillonite DK4 modified with double long-chain alkylammonium);

[0087] 40 parts of silicon source, which is silicone resin (methyl vinyl silicone rubber, viscosity 2 Pa·s, vinyl content 0.1%).

[0088] 0 parts of nucleating agent.

[0089] The preparation method is the same as in Example 1.

[0090] Comparative Example 2

[0091] A comparative ceramicized polyolefin cable material is composed of the following raw materials in parts by weight:

[0092] 100 parts of polyolefin elastomer, including 25 parts of EVA, 30 parts of POE, 25 parts of low-density polyethylene LLDPE (LX-1010), and 20 parts of metallocene polyethylene mPE (XP8784ML).

[0093] Compatibilizer: 3 parts maleic anhydride-grafted polyethylene;

[0094] One part of antioxidant, including 0.5 parts each of antioxidant 1010 and antioxidant DLTP;

[0095] Eight parts of rheology modifier, including four parts of silicone masterbatch and four parts of polyethylene wax;

[0096] Flame retardant 80 parts, including 60 parts aluminum hydroxide and 20 parts magnesium hydroxide;

[0097] 60 parts of acicular wollastonite as a skeleton filler;

[0098] 30 parts of ceramic filler, including 15 parts of montmorillonite and 15 parts of organically modified montmorillonite;

[0099] 30 parts of silicon source, which is silicone rubber;

[0100] Add 20 parts of phosphate low-melting-point glass powder (borosilicate system low-temperature glass powder, melting point 400-600℃) to replace the nucleating agent.

[0101] The preparation method is the same as in Example 1.

[0102] Comparative Example 3

[0103] A polyolefin composite material, comprising the following parts by weight of raw materials:

[0104] 100 parts of polyolefin elastomer, including 30 parts of EVA, 25 parts of POE, 25 parts of low-density polyethylene, and 20 parts of metallocene polyethylene;

[0105] Compatibilizer: 4 parts maleic anhydride-grafted polyethylene;

[0106] One part of antioxidant, including 0.5 parts each of antioxidant 1010 and antioxidant DLTP;

[0107] 10 parts of rheology modifier, including 5 parts of silicone masterbatch and 5 parts of polyethylene wax;

[0108] 160 parts of flame retardant, which is magnesium hydroxide;

[0109] 70 parts of acicular wollastonite as a skeleton filler;

[0110] 20 parts of ceramic filler, which is montmorillonite;

[0111] 0 silicon sources;

[0112] Nucleation aid 0 parts.

[0113] The preparation method is the same as in Example 1.

[0114] The materials obtained from the examples and comparative examples were subjected to performance tests, and the results are shown in Table 1.

[0115] The testing methods include:

[0116] GB / T 32129-2015 "Halogen-free Low-smoke Flame-retardant Cable Materials for Wires and Cables" defines the mechanical, aging, electrical, and toxic properties that halogen-free low-smoke flame-retardant thermoplastic polyolefin insulation and sheathing materials must meet; GB / T 19666-2019 "General Rules for Flame-retardant and Fire-resistant Wires, Cables or Optical Cables" defines the combination of fire-resistant series combustion characteristic codes; GB / T 31247-2014 "Classification of Combustion Performance of Cables and Optical Cables" defines the flame-retardant rating requirements that cables must meet, and this project requires a B1 flame-retardant rating; BS6387-2013 "Fire Resistance Test Method for Cables to Maintain Line Integrity under Flame Conditions" defines the requirements for fire resistance, spraying, and vibration.

[0117] Table 1 Comparison of performance test results between the examples and the comparative examples

[0118]

[0119] The method for testing the porcelain-forming temperature is as follows: Place the sample in an air-atmosphere muffle furnace and maintain it at the set temperature for 1 hour. After removing the sample, if it can maintain its shape after removal, it indicates that porcelain has been formed, and the set temperature is recorded as the porcelain-forming temperature. If the resulting residue does not have strong ash, it indicates that porcelain has not been formed.

[0120] As can be seen from Table 1, Comparative Example 1, due to the absence of nucleating agents, cannot effectively induce polyolefins to form carbon skeletons in advance and promote low-temperature eutectic reaction, resulting in high ceramic forming temperature. The resulting ceramic body has a loose structure, low bending strength and is prone to cracking. Although it can self-extinguish after being removed from the flame (V-1), its refractory performance is poor.

[0121] Comparative Example 2 contains low-melting-point glass powder, which can lower the ceramic forming temperature, but the glass phase continues to soften at high temperatures, causing the vertical combustion rating to drop to V-2 (not meeting the self-extinguishing requirement after flame removal), and the ceramic body undergoes slight melting and collapse at ≥1200℃, with high-temperature structural stability significantly inferior to that of the present invention.

[0122] Comparative Example 3 achieved self-extinguishing upon removal of flame and reached V-0 level through high-filling magnesium hydroxide (160 parts). However, due to the lack of synergistic ceramic-forming effect of nucleating aid and silicon source, it could not form an effective continuous ceramic structure, resulting in loose ceramic body, low strength, and pulverization without structure at high temperature. Its mechanical and ceramic properties were significantly lower than those of the embodiments of the present invention, which reflects the technical advantages of the "flux-free" synergistic ceramic-forming system of the present invention.

[0123] In Examples 1 and 2 of this invention, through the synergistic effect of the "flux-free" system and nucleating agent, excellent flame retardancy (V-0) and mechanical properties are ensured, while low-temperature ceramicization and extremely high high-temperature structural stability are achieved, and the overall performance is significantly better than that of the comparative example.

Claims

1. A polyolefin composite material, wherein, The polyolefin composite material comprises the following raw materials in parts by weight: 100 parts by weight of polyolefin elastomer, 2-5 parts by weight of compatibilizer, 0.5-3 parts by weight of antioxidant, 4-11 parts by weight of rheology modifier; 60-100 parts by weight of flame retardant, 40-80 parts by weight of skeleton filler, ceramic filler, 10-50 parts by weight of silicon source, and 1-10 parts by weight of nucleating agent; The polyolefin elastomer includes one or a combination of two of EVA and POE. The flame retardant includes one or more of aluminum hydroxide, magnesium hydroxide, and magnesium aluminum hydrotalcite. The ceramic filler comprises 10-30 parts by weight of montmorillonite and 5-20 parts by weight of organically modified montmorillonite; The nucleating agent includes montmorillonite and an active component supported on the montmorillonite, wherein the active component includes one or more of transition metal oxides and phosphates.

2. The polyolefin composite material according to claim 1, wherein, The polyolefin elastomer comprises 10-40 parts by weight of EVA, 10-40 parts by weight of POE, 10-40 parts by weight of low-density polyethylene, and 10-40 parts by weight of metallocene polyethylene.

3. The polyolefin composite material according to claim 1, wherein, In the nucleating agent, the active component accounts for 0.1% to 10% by weight.

4. The polyolefin composite material according to claim 1 or 3, wherein, The preparation method of the nucleating agent includes: mixing the active component precursor and montmorillonite, and heat-treating at 500~1200℃ to obtain the agent; wherein the active component precursor includes one or more of ferric chloride, nickel chloride, cobalt chloride, zinc acetate, titanate, and calcium phosphate.

5. The polyolefin composite material according to claim 1, wherein, The compatibilizer includes one or more of maleic anhydride-grafted polyethylene, acrylic acid-grafted polyolefin, and silane coupling agents.

6. The polyolefin composite material according to claim 1, wherein, The organically modified montmorillonite includes one or a combination of two of the following: high-purity organomontmorillonite DK4 modified with dual long-chain alkylammonium compounds and high-purity organomontmorillonite DK18 modified with long-chain alkylammonium compounds.

7. The polyolefin composite material according to claim 1, wherein, The antioxidants include one or more of antioxidants 1010, 1098, 1076, DLTP, DSDTP, 168, and 626.

8. The polyolefin composite material according to claim 1, wherein, The ceramic filler also includes one or a combination of two of bentonite and kaolin.

9. The polyolefin composite material according to claim 1, wherein, In the flame retardant, when magnesium hydroxide is used alone, the mass ratio of the polyolefin to magnesium hydroxide is 1:1 to 1:2; When the aluminum hydroxide is used alone, the mass ratio of the polyolefin to the aluminum hydroxide is 1:1 to 1:2; When using the aluminum hydroxide, the magnesium hydroxide, and the magnesium-aluminum hydrotalcite, the mass ratio of the polyolefin, the aluminum hydroxide, the magnesium hydroxide, and the magnesium-aluminum hydrotalcite is 1:0.4:0.6:0.1 to 1:0.8:1.2:

1.

10. The polyolefin composite material according to claim 1, wherein, The skeleton filler includes one or more of acicular wollastonite, sepiolite, and glass fiber.

11. The polyolefin composite material according to claim 1, wherein, The silicon source includes one or more of silicone rubber, silicone resin, and silane coupling agent modified silica.

12. The polyolefin composite material according to claim 1, wherein, The rheology modifier comprises 3-6 parts by weight of silicone masterbatch and 1-5 parts by weight of polyethylene wax.

13. A method for preparing a polyolefin composite material according to any one of claims 1 to 12, wherein, include: S1, the polyolefin elastomer, compatibilizer, antioxidant, rheology modifier, flame retardant, skeleton filler, ceramic filler, silicon source, and nucleating agent are blended at a blending temperature of 60-80℃ and a blending time of 10-20 min, with a stirring speed of 5-50 rpm to obtain the mixture. S2, the mixture is processed and shaped at a temperature of 140~160℃ to obtain the polyolefin composite material.

14. The method for preparing the polyolefin composite material according to claim 13, wherein, The processing and forming methods include twin-screw extrusion, internal mixing-single-screw extrusion, and continuous internal mixing-hot cutting into pellets.

15. The method for preparing the polyolefin composite material according to claim 14, wherein, During the extrusion process of the twin-screw extruder, the temperature is controlled as follows: Zone 1 140~145℃, Zone 2 145~150℃, Zone 3 150~155℃, Zone 4 155~160℃, Zone 5 160~165℃, Zone 6 165~170℃, Zone 7 160~165℃, Zone 8 155~160℃; Die head 140~150℃.

16. The method for preparing the polyolefin composite material according to claim 13, wherein, The preparation method further includes: drying the polyolefin composite material until the water content is ≤1wt%.

17. An application of a polyolefin composite material as a cable material, wherein, The polyolefin composite material is the polyolefin composite material according to any one of claims 1 to 12, or the polyolefin composite material is prepared by the method for preparing the polyolefin composite material according to any one of claims 13 to 16.

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