High-temperature-resistant polyolefin cable material and preparation method thereof

Abstract

The invention relates to the technical field of cable materials, and particularly discloses a high-temperature-resistant polyolefin cable material which is prepared from the following raw materials: 50 to 60 parts of homo-polypropylene, 20 to 25 parts of thermoplastic polyimide, 12 to 16 parts of aluminum nitride, 3 to 5 parts of vermiculite powder, 2.2 to 3.5 parts of antioxidant, 0.1 to 0.3 part of dicumyl peroxide, 0.5 to 0.8 part of triallyl isocyanurate, 22 to 36 parts of flame retardant and 2 to 3 parts of lubricant. The preparation method comprises the following steps: melting and plasticizing homo-polypropylene, and uniformly mixing the homo-polypropylene with thermoplastic polyimide; and uniformly mixing the mixture with aluminum nitride, vermiculite powder, an antioxidant and a flame retardant, adding dicumyl peroxide, triallyl isocyanurate and a lubricant, mixing, and extruding and granulating to obtain the high-temperature-resistant polyolefin cable material. The preparation method is helpful for improving the long-term high-temperature resistance of the polyolefin cable material.

Description

Technical Field

[0001] The present invention relates to the technical field of cable materials, in particular to a high-temperature resistant polyolefin cable material and a preparation method thereof. Background Art

[0002] Polyolefin materials are widely used in the insulation and sheathing of wires and cables due to their excellent electrical properties, processing flexibility, and cost advantages. However, with the development of new energy, aerospace, rail transportation and other fields, higher requirements are being placed on the high-temperature resistance of cables.

[0003] In the related art, a high-temperature resistant and flame-retardant polyolefin cable material is disclosed. The polyolefin cable material is composed of the following raw materials in parts by mass: 50-70 parts of polyolefin resin, 20-40 parts of cardanol grafted polyurethane, 10-25 parts of ionomer, 30-50 parts of composite flame retardant, 1-3 parts of lubricant and 0.2-1.2 parts of antioxidant; the polyolefin resin is composed of isotactic polypropylene and heterogeneous copolymer polypropylene in a mass ratio of 1:(0.1-0.2); the ionomer is EMAA copolymer or SEPS-g-MZn ionomer; and the composite flame retardant is a composite of modified polypropylene, magnesium hydroxide and ammonium polyphosphate.

[0004] However, cardanol contains a long-chain alkylphenol structure, which is easily oxidized and degraded at high temperatures. It is difficult for polyolefin cable materials to maintain stable performance for a long time in high temperature environments. Summary of the Invention

[0005] In order to improve the long-term high temperature resistance of polyolefin cable materials, the present application provides a high temperature resistant polyolefin cable material and a preparation method thereof.

[0006] In a first aspect, the present application provides a high-temperature resistant polyolefin cable material, which adopts the following technical solution:

[0007] A high-temperature resistant polyolefin cable material comprises the following raw materials in parts by weight: 50-60 parts of homopolypropylene, 20-25 parts of thermoplastic polyimide, 12-16 parts of aluminum nitride, 3-5 parts of vermiculite powder, 2.2-3.5 parts of antioxidant, 0.1-0.3 parts of dicumyl peroxide, 0.5-0.8 parts of triallyl isocyanurate, 22-36 parts of flame retardant, and 2-3 parts of lubricant.

[0008] In a specific embodiment, the flame retardant comprises poly(diphenyloxyphosphazene), magnesium hydroxide and phenolic resin-coated red phosphorus in a weight ratio of (3-5):(8-12):(15-20).

[0009] In a specific embodiment, the antioxidant includes antioxidant 1010, antioxidant 168 and oxalic acid anilide in a weight ratio of (0.8-1.2): (0.5-0.8): (0.4-0.6).

[0010] In a specific embodiment, the lubricant is polytetrafluoroethylene powder.

[0011] In a second aspect, the present application provides a method for preparing a high-temperature resistant polyolefin cable material, which adopts the following technical solution:

[0012] A method for preparing a high-temperature resistant polyolefin cable material comprises the following steps:

[0013] According to the ratio, homopolymer polypropylene is added into the twin-screw extruder, and after melting and plasticizing, thermoplastic polyimide is added and the mixing is continued to be uniform;

[0014] Aluminum nitride, vermiculite powder, antioxidant and flame retardant are added and mixed evenly, and then dicumyl peroxide, triallyl isocyanurate and lubricant are added. The mixture is mixed at 190-210° C. for 3 minutes and extruded into granules to obtain a high-temperature resistant polyolefin cable material.

[0015] In a specific embodiment, the aluminum nitride and vermiculite powder are pre-treated as follows: the aluminum nitride and vermiculite powder are vacuum dried at 110-125° C. for 3-5 hours.

[0016] In a specific embodiment, the flame retardant is prepared according to the following steps: poly(diphenoxyphosphazene), magnesium hydroxide and phenolic resin-coated red phosphorus are uniformly mixed in a weight ratio of (3-5): (8-12): (15-20) to obtain a flame retardant.

[0017] In a specific embodiment, the phenolic resin-coated red phosphorus is pre-treated as follows: the phenolic resin-coated red phosphorus is soaked in an ethanol solution of 1% by mass of a silane coupling agent with a solid-liquid ratio of 1:5 for 30 minutes, filtered, and then dried at 80° C. for 2 hours.

[0018] In a specific embodiment, the phenolic resin-coated red phosphorus is prepared according to the following steps:

[0019] Grind and sieve red phosphorus to obtain red phosphorus powder with a particle size of 5-10 μm;

[0020] The oil-soluble phenolic resin and xylene are uniformly mixed in a volume ratio of 1:(2.5-3.0) to obtain a phenolic resin solution;

[0021] The red phosphorus powder and the phenolic resin solution are mixed uniformly to obtain a mixed solution; the mass of the oil-soluble phenolic resin in the mixed solution is 1-5% of the mass of the red phosphorus powder;

[0022] The mixed solution is dried at 55-65° C. to obtain phenolic resin-coated red phosphorus.

[0023] In summary, this application has the following beneficial effects:

[0024] 1. This application uses a specific proportion of homopolymer polypropylene, thermoplastic polyimide, aluminum nitride, vermiculite powder, diisopropylbenzene peroxide, triallyl isocyanurate and other additives, and adopts the preparation method of this application to prepare a polyolefin cable material that can maintain stable performance for a long time in a high temperature environment, which is more suitable for cables working in a high temperature environment.

[0025] 2. In this application, a mixture of poly(diphenoxyphosphazene), magnesium hydroxide and phenolic resin-coated red phosphorus in a specific ratio is preferably used as a flame retardant, a mixture of antioxidant 1010, antioxidant 168 and oxalic acid anilide is used as an antioxidant, and polytetrafluoroethylene powder is used as a lubricant, which can further improve the long-term high temperature resistance of polyolefin cable materials.

[0026] 3. The method of the present application is simple to operate and suitable for large-scale production. DETAILED DESCRIPTION

[0027] Unless otherwise specified, the raw materials used in this application are all commercially available. Homopolymer polypropylene is LyondellBasell, Moplen HP501M. Thermoplastic polyimide is Japan Mitsui, AURUM JCL3030. Vermiculite powder was purchased from Lingshou County Yongqi Mineral Products Co., Ltd., with a particle size of 325 mesh. Diisopropyl peroxide was purchased from Nanjing Chemical Reagent Co., Ltd. Triallyl isocyanurate was purchased from Wuhan Kemik Biopharmaceutical Technology Co., Ltd. Poly(diphenoxyphosphazene) was purchased from Hubei Keji Biopharmaceutical Technology Co., Ltd. Oil-soluble phenolic resin was purchased from Shandong Ap Chemical Technology Co., Ltd. Oxalanilide was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd. Polytetrafluoroethylene micropowder was purchased from Dongguan Hongyu Plastic Co., Ltd.

[0028] The present application is further described in detail below with reference to the following examples and comparative examples.

[0029] Example

[0030] Example 1

[0031] This embodiment provides a high-temperature-resistant polyolefin cable material, comprising the following raw materials: 55 kg of homopolypropylene, 22.5 kg of thermoplastic polyimide, 14 kg of aluminum nitride, 4 kg of vermiculite powder, 2.8 kg of antioxidant, 0.2 kg of dicumyl peroxide, 0.65 kg of triallyl isocyanurate, 29 kg of flame retardant, and 2.5 kg of lubricant. In this embodiment, the flame retardant is magnesium hydroxide, the antioxidant is antioxidant 1010, and the lubricant is DuPont 500T NC010.

[0032] This embodiment also provides a method for preparing a high-temperature resistant polyolefin cable material, comprising the following steps:

[0033] According to the ratio, homopolymer polypropylene is added into the feeding section of the twin-screw extruder. After melting and plasticizing for 3 minutes, it enters the compression section and thermoplastic polyimide is added. The mixing is continued until uniform so that the resin phase is evenly dispersed.

[0034] Then it enters the melting section, and aluminum nitride, vermiculite powder, antioxidant and flame retardant are added in sequence. After mixing evenly, it enters the homogenization section, and dicumyl peroxide, triallyl isocyanurate and lubricant are added. After mixing for 3 minutes, it is extruded and granulated to obtain high-temperature resistant polyolefin cable material.

[0035] The barrel temperature of the twin-screw extruder is controlled in sections as follows: feeding section 160-170°C, compression section 170-185°C, melting section 185-200°C, homogenization section 190-210°C. The screw speed is 200-250r / min.

[0036] Example 2

[0037] The only difference between this embodiment and Example 1 is that the high-temperature resistant polyolefin cable material includes the following raw materials: 50 kg of homopolypropylene, 25 kg of thermoplastic polyimide, 16 kg of aluminum nitride, 5 kg of vermiculite powder, 3.5 kg of antioxidant, 0.3 kg of diisopropyl peroxide, 0.8 kg of triallyl isocyanurate, 36 kg of flame retardant, and 3 kg of lubricant.

[0038] Example 3

[0039] The only difference between this embodiment and Example 1 is that the high-temperature resistant polyolefin cable material includes the following raw materials: 60 kg of homopolypropylene, 20 kg of thermoplastic polyimide, 12 kg of aluminum nitride, 3 kg of vermiculite powder, 2.2 kg of antioxidant, 0.1 kg of diisopropyl benzene peroxide, 0.5 kg of triallyl isocyanurate, 22 kg of flame retardant, and 2 kg of lubricant.

[0040] Example 4

[0041] The only difference between this embodiment and embodiment 1 is that, in the method for preparing the high-temperature resistant polyolefin cable material, aluminum nitride and vermiculite powder are placed in a vacuum drying oven in advance, vacuum-dried at 110° C. for 5 hours, and then added to the twin-screw extruder.

[0042] Example 5

[0043] The only difference between this embodiment and embodiment 1 is that, in the method for preparing the high-temperature resistant polyolefin cable material, aluminum nitride and vermiculite powder are placed in a vacuum drying oven in advance, vacuum-dried at 125° C. for 3 hours, and then added to the twin-screw extruder.

[0044] Example 6

[0045] This embodiment differs from Example 1 only in that the flame retardant in this embodiment comprises poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus in a weight ratio of 4:10:17. The flame retardant is obtained by uniformly mixing the poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus.

[0046] Phenolic resin coated red phosphorus was prepared according to the following steps:

[0047] The red phosphorus is ground and sieved to obtain red phosphorus powder with a particle size of 5-10 μm.

[0048] The oil-soluble phenolic resin and xylene were mixed in a volume ratio of 1:2.7 and stirred evenly to obtain a phenolic resin solution.

[0049] The red phosphorus powder and the phenolic resin solution are uniformly mixed to obtain a mixed solution, wherein the mass of the oil-soluble phenolic resin in the mixed solution is 3% of the mass of the red phosphorus powder; the mixed solution is sent to a dryer with a xylene recovery device, and after drying at 60° C., the phenolic resin-coated red phosphorus is obtained.

[0050] Example 7

[0051] This embodiment differs from Example 1 only in that the flame retardant in this embodiment comprises poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus in a weight ratio of 3:12:20. The flame retardant is obtained by uniformly mixing the poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus.

[0052] Phenolic resin coated red phosphorus was prepared according to the following steps:

[0053] The red phosphorus is ground and sieved to obtain red phosphorus powder with a particle size of 5-10 μm.

[0054] The oil-soluble phenolic resin and xylene were mixed in a volume ratio of 1:2.7 and stirred evenly to obtain a phenolic resin solution.

[0055] The red phosphorus powder and the phenolic resin solution are uniformly mixed to obtain a mixed solution, wherein the mass of the oil-soluble phenolic resin in the mixed solution is 3% of the mass of the red phosphorus powder; the mixed solution is sent to a dryer with a xylene recovery device, and after drying at 60° C., the phenolic resin-coated red phosphorus is obtained.

[0056] Example 8

[0057] This embodiment differs from Example 1 only in that the flame retardant in this embodiment comprises poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus in a weight ratio of 5:8:15. The flame retardant is obtained by uniformly mixing the poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus.

[0058] Phenolic resin coated red phosphorus was prepared according to the following steps:

[0059] The red phosphorus is ground and sieved to obtain red phosphorus powder with a particle size of 5-10 μm.

[0060] The oil-soluble phenolic resin and xylene were mixed in a volume ratio of 1:2.7 and stirred evenly to obtain a phenolic resin solution.

[0061] The red phosphorus powder and the phenolic resin solution are uniformly mixed to obtain a mixed solution, wherein the mass of the oil-soluble phenolic resin in the mixed solution is 3% of the mass of the red phosphorus powder; the mixed solution is sent to a dryer with a xylene recovery device, and after drying at 60° C., the phenolic resin-coated red phosphorus is obtained.

[0062] Implementation 9

[0063] This embodiment differs from Example 6 only in that the phenolic resin-coated red phosphorus is pre-treated as follows: the phenolic resin-coated red phosphorus is soaked in an ethanol solution containing 1% by mass of the silane coupling agent KH-560 for 30 minutes at a solid-to-liquid ratio of 1:5. After filtration, the solution is air-dried at 80°C for 2 hours. The treated phenolic resin-coated red phosphorus is then uniformly mixed with poly(diphenoxyphosphazene) and magnesium hydroxide to produce a flame retardant.

[0064] Implementation 10

[0065] The only difference between this embodiment and embodiment 6 is that the phenolic resin-coated red phosphorus is prepared according to the following steps:

[0066] The red phosphorus is ground and sieved to obtain red phosphorus powder with a particle size of 5-10 μm.

[0067] The oil-soluble phenolic resin and xylene were mixed in a volume ratio of 1:2.5 and stirred evenly to obtain a phenolic resin solution.

[0068] The red phosphorus powder and the phenolic resin solution are uniformly mixed to obtain a mixed solution, wherein the mass of the oil-soluble phenolic resin in the mixed solution is 1% of the mass of the red phosphorus powder; the mixed solution is sent to a dryer with a xylene recovery device, and after drying at 55° C., the phenolic resin-coated red phosphorus is obtained.

[0069] Implementation 11

[0070] The only difference between this embodiment and embodiment 6 is that the phenolic resin-coated red phosphorus is prepared according to the following steps:

[0071] The red phosphorus is ground and sieved to obtain red phosphorus powder with a particle size of 5-10 μm.

[0072] The oil-soluble phenolic resin and xylene were mixed in a volume ratio of 1:2.5 and stirred evenly to obtain a phenolic resin solution.

[0073] The red phosphorus powder and the phenolic resin solution are uniformly mixed to obtain a mixed solution, wherein the mass of the oil-soluble phenolic resin in the mixed solution is 5% of the mass of the red phosphorus powder; the mixed solution is sent to a dryer with a xylene recovery device, and after drying at 65° C., the phenolic resin-coated red phosphorus is obtained.

[0074] Example 12

[0075] The only difference between this embodiment and embodiment 1 is that the antioxidant in this embodiment includes antioxidant 1010, antioxidant 168, and oxalic acid anilide in a weight ratio of 1:0.65:0.5. Antioxidant 1010, antioxidant 168, and oxalic acid anilide are uniformly mixed to obtain an antioxidant.

[0076] Example 13

[0077] The only difference between this embodiment and embodiment 1 is that the antioxidant in this embodiment includes antioxidant 1010, antioxidant 168, and oxalic acid anilide in a weight ratio of 0.8:0.8:0.6. Antioxidant 1010, antioxidant 168, and oxalic acid anilide are uniformly mixed to obtain an antioxidant.

[0078] Example 14

[0079] The only difference between this embodiment and embodiment 1 is that the antioxidant in this embodiment includes antioxidant 1010, antioxidant 168, and oxalic acid anilide in a weight ratio of 1.2:0.5:0.4. Antioxidant 1010, antioxidant 168, and oxalic acid anilide are uniformly mixed to obtain an antioxidant.

[0080] Example 15

[0081] The only difference between this embodiment and embodiment 1 is that the lubricant in this embodiment is polytetrafluoroethylene powder.

[0082] Example 16

[0083] This embodiment differs from Example 1 only in that the high-temperature-resistant polyolefin cable material comprises the following raw materials: 55 kg of homopolypropylene, 22.5 kg of thermoplastic polyimide, 14 kg of aluminum nitride, 4 kg of vermiculite powder, 2.8 kg of antioxidant, 0.2 kg of dicumyl peroxide, 0.65 kg of triallyl isocyanurate, 29 kg of flame retardant, and 2.5 kg of lubricant. The flame retardant in this embodiment comprises poly(diphenoxyphosphazene), magnesium hydroxide, and phenolic resin-coated red phosphorus in a weight ratio of 4:10:17. The antioxidant comprises antioxidant 1010, antioxidant 168, and oxalic acid anilide in a weight ratio of 1:0.65:0.5. The lubricant is polytetrafluoroethylene micropowder.

[0084] The antioxidant 1010, the antioxidant 168 and the oxalic acid anilide are uniformly mixed to obtain the antioxidant.

[0085] Phenolic resin coated red phosphorus was prepared according to the following steps:

[0086] The red phosphorus is ground and sieved to obtain red phosphorus powder with a particle size of 5-10 μm.

[0087] The oil-soluble phenolic resin and xylene were mixed in a volume ratio of 1:2.7 and stirred evenly to obtain a phenolic resin solution.

[0088] The red phosphorus powder and the phenolic resin solution are uniformly mixed to obtain a mixed solution, wherein the mass of the oil-soluble phenolic resin in the mixed solution is 3% of the mass of the red phosphorus powder; the mixed solution is sent to a dryer with a xylene recovery device, and after drying at 60° C., the phenolic resin-coated red phosphorus is obtained.

[0089] The phenolic resin-coated red phosphorus was pre-treated as follows: the phenolic resin-coated red phosphorus was soaked in an ethanol solution containing 1% by mass of a silane coupling agent at a solid-to-liquid ratio of 1:5 for 30 minutes, filtered, and air-dried at 80°C for 2 hours. Poly(diphenoxyphosphazene), magnesium hydroxide, and the phenolic resin-coated red phosphorus were then mixed uniformly to obtain a flame retardant.

[0090] This embodiment also provides a method for preparing a high-temperature resistant polyolefin cable material, comprising the following steps:

[0091] According to the ratio, homopolymer polypropylene is added into the feeding section of the twin-screw extruder. After melting and plasticizing for 3 minutes, it enters the compression section and thermoplastic polyimide is added. The mixing is continued until uniform so that the resin phase is evenly dispersed.

[0092] The material then enters the melting section. In the method for preparing high-temperature-resistant polyolefin cable material, aluminum nitride and vermiculite powder are first placed in a vacuum drying oven and vacuum-dried at 110°C for 5 hours. The aluminum nitride, vermiculite powder, antioxidant, and flame retardant are then added sequentially to a twin-screw extruder and mixed evenly before entering the homogenization section. Dicumyl peroxide, triallyl isocyanurate, and lubricant are then added, mixed for 3 minutes, and extruded into granules to produce the high-temperature-resistant polyolefin cable material.

[0093] The barrel temperature of the twin-screw extruder is controlled in sections as follows: feeding section 160-170°C, compression section 170-185°C, melting section 185-200°C, homogenization section 190-210°C. The screw speed is 200-250r / min.

[0094] Comparative Example

[0095] Comparative Example 1

[0096] The only difference between this comparative example and Example 1 is that the thermoplastic polyimide is replaced by an equal amount of homopolymer polypropylene.

[0097] Comparative Example 2

[0098] The only difference between this comparative example and Example 1 is that the homopolymer polypropylene is replaced by an equal amount of thermoplastic polyimide.

[0099] Comparative Example 3

[0100] The only difference between this comparative example and Example 1 is that an equal amount of homopolypropylene is used to replace aluminum nitride.

[0101] Comparative Example 4

[0102] The only difference between this comparative example and Example 1 is that the vermiculite powder is replaced by an equal amount of homopolypropylene.

[0103] Comparative Example 5

[0104] The only difference between this comparative example and Example 1 is that an equal amount of homopolypropylene is used to replace dicumyl peroxide.

[0105] Comparative Example 6

[0106] The only difference between this comparative example and Example 1 is that an equal amount of homopolypropylene is used to replace triallyl isocyanurate.

[0107] Performance testing

[0108] For Examples 1-16 and Comparative Examples 1-6, the following performance tests were performed:

[0109] (1) Sample preparation

[0110] Sample forming

[0111] Take the cable material particles to be tested and use an injection molding machine (barrel temperature 190-210℃, mold temperature 60℃) to injection mold the following standard specimens:

[0112] Tensile specimen: Type I dumbbell piece (length 150 mm, effective part length 50 mm) as specified in GB / T1040.2-2006;

[0113] Volume resistivity specimen: Φ50mm×2mm disc (in accordance with GB / T1410-2006);

[0114] Oxygen index test specimen: 120mm long x 10mm wide x 4mm thick (in compliance with GB / T2406.2-2009). Each set of test specimens should be ≥ 5 and placed in an environment of (23±2)°C and relative humidity of (50±5)% for 24 hours for standby use.

[0115] (2) Initial performance test (benchmark value before aging)

[0116] Tensile properties: The tensile strength (σ0) was tested using a universal material testing machine (accuracy ±1%) at a tensile speed of 50 mm / min, and the average value of 5 specimens was taken.

[0117] Volume resistivity: Use a high resistance meter (test voltage 500V, electrode system is three electrodes) to test the volume resistivity (ρ0) at room temperature. Each sample is tested three times and the average value is taken.

[0118] (3) Long-term thermal aging test

[0119] Aging temperature: According to the design operating temperature of the material, select 150°C;

[0120] Aging time: 3000h, 5000h;

[0121] Aging equipment: forced ventilation thermal aging box (temperature fluctuation ≤ ± 2 ° C, air change rate 3-10 times / h, to avoid accumulation of volatile substances).

[0122] Aging operation: Hang the specimens in the aging oven (specimen spacing ≥ 10mm, not touching the chamber wall) and age continuously at the set temperature and time without removing the specimens. After aging, close the oven and allow the specimens to cool naturally to (23±2)°C. Place them in a standard environment for 4 hours before testing their performance.

[0123] (IV) Performance test after aging

[0124] Following the same method as the “initial performance test”, test the tensile strength (σ) and volume resistivity (ρ) after aging, and calculate the performance retention rate:

[0125] Tensile strength retention rate = |(σ / σ0)| × 100%

[0126] Volume resistivity change rate = |(ρ-ρ0) / ρ0| × 100%

[0127] The test results are shown in Table 1.

[0128] Table 1

[0129]

[0130] Combining Example 1 with Comparative Examples 1-6 and Table 1, it can be seen that, compared to Example 1, after aging at 150°C for 3000 h or 5000 h, the tensile strength retention of Comparative Examples 1-6 was significantly lower, and the volume resistivity change rate was significantly higher. This indicates that the raw material ratio and preparation method of Example 1 help improve the long-term high-temperature resistance of the polyolefin cable material, allowing the prepared polyolefin cable material to maintain stable performance over a long period of time in high-temperature environments.

[0131] Combining Examples 1-16 with Table 1, it can be seen that the polyolefin cable materials prepared in Examples 1-16 all exhibited tensile strength retention rates greater than 85% and volume resistivity changes less than 20% after aging at 150°C for 3000 hours. After aging at 150°C for 5000 hours, the tensile strength retention rates were greater than 80%, and the volume resistivity changes were less than 25%. Furthermore, compared to Comparative Examples 1-6, the differences in tensile strength retention and volume resistivity changes for the polyolefin cable materials prepared in the same Examples after aging at 150°C for 3000 hours and 5000 hours were both smaller. This demonstrates that polyolefin cable materials with long-term high-temperature resistance can be produced using the raw material ratios and technical solutions within the preparation method range of Examples 1-16.

[0132] Moreover, by comparing the test results of Examples 1-16, it can be seen that Examples 4-16 have a higher tensile strength retention rate and a lower volume resistivity change rate, among which Example 16 has the highest tensile strength retention rate and the lowest volume resistivity change rate. This shows that the raw material ratio and preparation method of Example 16 can help further improve the long-term high temperature resistance of polyolefin cable materials.

[0133] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high temperature resistant polyolefin cable material, characterized in that: The invention comprises the following raw materials in parts by weight: 50-60 parts of homopolypropylene, 20-25 parts of thermoplastic polyimide, 12-16 parts of aluminum nitride, 3-5 parts of vermiculite powder, 2.2-3.5 parts of antioxidant, 0.1-0.3 parts of dicumyl peroxide, 0.5-0.8 parts of triallyl isocyanurate, 22-36 parts of flame retardant and 2-3 parts of lubricant.

2. The high temperature resistant polyolefin cable material according to claim 1, characterized in that: The flame retardant comprises poly(diphenoxyphosphazene), magnesium hydroxide and phenolic resin-coated red phosphorus in a weight ratio of (3-5):(8-12):(15-20).

3. The high temperature resistant polyolefin cable material according to claim 1, characterized in that: The antioxidant comprises antioxidant 1010, antioxidant 168 and oxalic acid anilide in a weight ratio of (0.8-1.2):(0.5-0.8):(0.4-0.6).

4. The high temperature resistant polyolefin cable material according to claim 1, characterized in that: The lubricant is polytetrafluoroethylene powder.

5. A method for preparing a high-temperature resistant polyolefin cable material according to any one of claims 1 to 4, characterized in that: The steps include: According to the ratio, homopolymer polypropylene is added into the twin-screw extruder, and after melting and plasticizing, thermoplastic polyimide is added and the mixing is continued to be uniform; Aluminum nitride, vermiculite powder, antioxidant and flame retardant are added and mixed evenly, and then dicumyl peroxide, triallyl isocyanurate and lubricant are added. The mixture is mixed at 190-210° C. for 3 minutes and extruded into granules to obtain a high-temperature resistant polyolefin cable material.

6. The method for preparing a high-temperature resistant polyolefin cable material according to claim 5, characterized in that: Aluminum nitride and vermiculite powder are treated in advance as follows: aluminum nitride and vermiculite powder are vacuum dried at 110-125° C. for 3-5 hours.

7. The method for preparing a high-temperature resistant polyolefin cable material according to claim 5, characterized in that: The flame retardant is prepared according to the following steps: poly(diphenoxyphosphazene), magnesium hydroxide and phenolic resin-coated red phosphorus are uniformly mixed in a weight ratio of (3-5): (8-12): (15-20) to obtain the flame retardant.

8. The method for preparing a high-temperature resistant polyolefin cable material according to claim 7, characterized in that: The phenolic resin-coated red phosphorus was pre-treated as follows: the phenolic resin-coated red phosphorus was soaked in an ethanol solution of a silane coupling agent with a mass fraction of 1% for 30 minutes, with a solid-liquid ratio of 1:5, filtered, and then dried at 80° C. for 2 hours.

9. The method for preparing a high-temperature resistant polyolefin cable material according to claim 5, wherein: The phenolic resin-coated red phosphorus is prepared according to the following steps: Grind and sieve red phosphorus to obtain red phosphorus powder with a particle size of 5-10 μm; The oil-soluble phenolic resin and xylene are uniformly mixed in a volume ratio of 1:(2.5-3.0) to obtain a phenolic resin solution; The red phosphorus powder and the phenolic resin solution are mixed uniformly to obtain a mixed solution; the mass of the oil-soluble phenolic resin in the mixed solution is 1-5% of the mass of the red phosphorus powder; The mixed solution is dried at 55-65° C. to obtain phenolic resin-coated red phosphorus.

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