Twist-resistant anti-cracking flexible cable sheath material for wind power generation and preparation method thereof

Abstract

The invention discloses a distortion-resistant anti-cracking flexible cable sheath material for wind power generation and a preparation method thereof, and belongs to the technical field of cable sheath materials. The cable sheath material is prepared from the following raw materials in parts by mass: 90-110 parts of chlorinated polyethylene, 20-30 parts of carbon black, 10-15 parts of light calcium carbonate, 1-2 parts of white carbon black, 10-15 parts of talcum powder, 4-6 parts of active magnesium oxide, 2-3 parts of dicumyl peroxide, 1-2 parts of triallyl isocyanurate, 5-8 parts of a plasticizer, 2-3 parts of an anti-aging agent, 0.5-1 part of 4, 4-bis (alpha, alpha-dimethylbenzyl) diphenylamine, 0.5-1 part of N-(1, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate) and 1-2 parts of a coupling agent. 1-3 parts of 2, 3-dimethylbutyl)-N '-phenyl p-phenylenediamine, 4-5 parts of a flame retardant and 1-2 parts of a silane coupling agent. The material provided by the invention has excellent distortion resistance, aging resistance and oxidation resistance in a wide temperature range.

Description

Technical Field

[0001] The present invention relates to the technical field of cable sheath materials, in particular to a twisting and cracking resistant soft cable sheath material for wind power generation and a preparation method thereof. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] In the actual operating environment of wind turbines, cables, as a key component, face multiple challenges. First, cables need to adapt to a wide range of ambient temperatures, from extremely cold to extremely high temperatures, and are typically required to operate stably in temperatures ranging from -40°C to 50°C, or even as high as 90°C. In certain high-latitude or high-altitude areas, winter temperatures are particularly low and the temperature difference between day and night is significant, posing a severe test on the low-temperature flexibility and cold resistance of the cable sheathing material. Second, to achieve automatic yaw of the wind turbine, the cable needs to undergo frequent twisting motions. This continuous, large-angle twisting motion requires the cable to possess excellent torsional flexibility to reduce internal stress and losses. Furthermore, because wind turbine towers are typically very tall, the cables need to be laid vertically in the air, which requires the cables themselves to possess exceptional vertical tensile strength.

[0004] However, existing wind turbine cables have significant shortcomings in meeting these comprehensive requirements. A core issue is that during prolonged energized operation, the conductors continuously heat up, causing thermal aging of the insulation and sheath materials and gradual degradation of their mechanical properties. Furthermore, the cables are subjected to periodic torsional stress during wind turbine yaw. The combined effects of thermal aging and mechanical stress increase the susceptibility of the cable sheath material to fatigue damage. Particularly at low temperatures, the sheath material becomes brittle, significantly reducing its crack resistance. This directly leads to the widespread sheath cracking of existing wind turbine cables after several years of operation (typically around five years). This not only affects the stability and safety of power transmission, but also shortens the cable's lifespan and increases maintenance costs. Furthermore, the presence of ozone in the operating environment, coupled with the presence of various electrical devices within wind turbines, can accelerate the aging and cracking of certain sheath materials.

[0005] Therefore, developing a sheath material that can maintain flexibility in a wide temperature range, resist frequent torsional stress, delay the thermal aging process, and have excellent ozone resistance to significantly improve the durability and service life of wind power cables has become a key technical problem that needs to be solved urgently. Summary of the Invention

[0006] In view of this, the present invention provides a torsion-resistant and crack-resistant soft cable sheath material for wind power generation and a preparation method thereof. The torsion-resistant and crack-resistant soft cable sheath material for wind power generation of the present invention has good flexibility, good torsion resistance at low temperatures, and excellent aging resistance and ozone resistance.

[0007] In a first aspect, the present invention provides a twisting and cracking resistant flexible cable sheath material for wind power generation, which is made from the following raw materials in parts by weight: 90-110 parts of chlorinated polyethylene, 20-30 parts of carbon black, 10-15 parts of light calcium carbonate, 1-2 parts of white carbon black, 10-15 parts of talc, 4-6 parts of active magnesium oxide, 2-3 parts of dicumyl peroxide, 1-2 parts of triallyl isocyanurate, 5-8 parts of plasticizer, 2-3 parts of antioxidant, 0.5-1 part of 4,4-bis(α,α-dimethylbenzyl)diphenylamine, 1-3 parts of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4-5 parts of flame retardant, and 1-2 parts of silane coupling agent.

[0008] Preferably, the silane coupling agent includes one or more of KH550, KH560 or KH570.

[0009] Preferably, the plasticizer comprises dioctyl sebacate and trioctyl trimellitate, and the mass ratio of dioctyl sebacate to trioctyl trimellitate is 1:(1~3).

[0010] Preferably, the antioxidant includes antioxidant 4010NA and antioxidant MBZ.

[0011] Furthermore, the mass ratio of antioxidant 4010NA to antioxidant MBZ is (1~3):1.

[0012] Preferably, the flame retardant includes antimony trioxide and tetrabromobisphenol A.

[0013] Furthermore, the mass ratio of antimony trioxide to tetrabromobisphenol A is 1: (2~5).

[0014] In a second aspect, the present invention provides a method for preparing the above-mentioned twisting and cracking resistant flexible cable sheath material for wind power generation, comprising the following steps: Carbon black, white carbon black and active magnesium oxide are mixed and then modified with a silane coupling agent to prepare modified carbon black, modified white carbon black and modified active magnesium oxide; Chlorinated polyethylene, modified carbon black, light calcium carbonate, modified white carbon black, talc, modified active magnesium oxide, dicumyl peroxide, triallyl isocyanurate, plasticizer, antioxidant, 4,4-bis(α,α-dimethylbenzyl)diphenylamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and flame retardant are mixed and then subjected to open refining; and then vulcanized to obtain a twisting and cracking resistant soft cable sheath material for wind power generation.

[0015] Preferably, the refining temperature is 60-70°C; the vulcanization temperature is 160-195°C, and the vulcanization time is 8-20 minutes.

[0016] Preferably, the preparation method of the modified carbon black, modified white carbon black and modified active magnesium oxide comprises the following steps: dissolving a silane coupling agent in an ethanol aqueous solution with a pH of 4 to 6 to obtain a mixed solution; The mixed liquid is used to spray carbon black and / or white carbon black and / or active magnesium oxide, and then dried at 70-90° C. for 24-48 hours to obtain modified carbon black, modified white carbon black and modified active magnesium oxide.

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) The present invention uses chlorinated polyethylene as the base material, and improves the mechanical properties, wear resistance, lubricity and anti-stickiness of the material by adding low-cost inorganic fillers, and improves the flexibility and cold resistance of the material by adding plasticizers. At the same time, the synergistic effect of antioxidants, 4,4-bis(α,α-dimethylbenzyl)diphenyl and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine is used to improve the torsion resistance, aging resistance and oxidation resistance of the cable sheath material in a wide temperature range.

[0018] (2) The twisting and cracking resistant soft cable sheath material for wind power generation of the present invention can withstand more than 3,000 twists at a low temperature of -40°C and more than 15,000 twists at room temperature due to the synergistic effect of various components. It avoids the problem of early cracking of the sheath caused by the superposition of heat / ozone aging and mechanical stress in traditional cable sheath materials, and can be used in a wide temperature range. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0020] The present invention provides a twisting and cracking resistant flexible cable sheath material for wind power generation, which is prepared from the following raw materials in parts by weight: 90-110 parts of chlorinated polyethylene, 20-30 parts of carbon black, 10-15 parts of light calcium carbonate, 1-2 parts of white carbon black, 10-15 parts of talc, 4-6 parts of active magnesium oxide, 2-3 parts of dicumyl peroxide, 1-2 parts of triallyl isocyanurate, 5-8 parts of plasticizer, 2-3 parts of antioxidant, 0.5-1 part of 4,4-bis(α,α-dimethylbenzyl)diphenylamine, 1-3 parts of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4-5 parts of flame retardant, and 1-2 parts of silane coupling agent.

[0021] The twist-resistant and crack-resistant flexible cable sheath material for wind power generation uses chlorinated polyethylene (CPE) as its base material. The chlorine atoms in its molecular chains impart certain flame retardancy to the material. This multi-component synergistic effect addresses the cracking and short lifespan issues of conventional cable sheath materials in extreme low temperatures, frequent torsion, and ozone environments. Carbon black enhances tensile strength and wear resistance, effectively resisting the tensile loads of vertical installation. Light calcium carbonate improves the material's mechanical properties while reducing costs, while also regulating its overall density. Silica fills the gaps between CPE molecular chains, enhancing strength, wear resistance, and flex fatigue resistance. Talc improves the material's lubricity and anti-stick properties. Activated magnesium oxide enhances the stability of the cable sheath material by efficiently absorbing HCl generated by the thermal decomposition of CPE through a chemical reaction, blocking autocatalytic degradation and slowing matrix aging. Dicumyl peroxide and triallyl isocyanurate form a highly efficient vulcanization system, allowing the material to form a stable CC crosslinked network during vulcanization, preventing performance degradation caused by overvulcanization. The introduction of plasticizers can lower the glass transition temperature of CPE and improve the flexibility of the material at low temperatures. The introduction of flame retardants can improve the flame retardancy of the material. The present invention forms a full-dimensional protection covering mechanical stress, thermal oxidative aging, high-temperature degradation and ozone erosion through the synergistic effect of antioxidants with 4,4-bis(α,α-dimethylbenzyl)diphenylamine and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, significantly improving the torsion resistance, aging resistance and antioxidant properties of the cable sheath material in a wide temperature range. The introduction of silane coupling agents can significantly improve the dispersibility and compatibility of inorganic fillers (including carbon black, white carbon black and activated magnesium oxide) in the matrix material. Through the above-mentioned formula design, the present invention can achieve tolerance of more than 3,000 torsions at a low temperature of -40°C and more than 15,000 torsions at room temperature.

[0022] The carbon black of the present invention preferably adopts high specific surface area carbon black, such as N330 or N660.

[0023] In the present invention, the silane coupling agent includes one or more of KH550, KH560, or KH570. Modifying the hydroxyl groups on the surface of the inorganic filler with the silane coupling agent can significantly improve the dispersibility of the inorganic filler in the matrix material and the compatibility with the matrix material.

[0024] In the present invention, the plasticizers include dioctyl sebacate and trioctyl trimellitate. Dioctyl sebacate is a long-chain ester plasticizer that significantly lowers the glass transition temperature of CPE, while trioctyl trimellitate is a high-temperature-resistant plasticizer that reduces high-temperature migration and volatilization. The mass ratio of dioctyl sebacate to trioctyl trimellitate is 1:1-3, which balances low-temperature performance and durability, preventing plasticizer precipitation from hardening the sheath material.

[0025] In the present invention, the antioxidant includes antioxidant 4010NA and antioxidant MBZ. Antiaging agent 4010NA is a phenylenediamine antioxidant that can preferentially migrate to the material surface and capture free radicals generated by dynamic distortion. Antiaging agent MBZ is a benzimidazole zinc salt that can inhibit thermal oxidative aging within the matrix and complex copper ion impurities. Furthermore, the mass ratio of antioxidant 4010NA to antioxidant MBZ is (1-3):1.

[0026] In the present invention, the flame retardant comprises antimony trioxide and tetrabromobisphenol A. Tetrabromobisphenol A decomposes upon heating to produce HBr radicals, which react with antimony trioxide to form SbBr3 (gaseous), thereby isolating oxygen and terminating the combustion chain reaction. Furthermore, the mass ratio of antimony trioxide to tetrabromobisphenol A is 1:(2-5); at this ratio, the two can achieve optimal synergistic flame retardancy. In the present invention, antimony trioxide is preferably modified with a silane coupling agent to enhance its compatibility with the substrate material.

[0027] The present invention also provides a method for preparing the above-mentioned twisting and cracking resistant flexible cable sheath material for wind power generation, comprising the following steps: Carbon black, white carbon black and active magnesium oxide are mixed and then modified with a silane coupling agent to prepare modified carbon black, modified white carbon black and modified active magnesium oxide; Chlorinated polyethylene, modified carbon black, light calcium carbonate, modified white carbon black, talc, modified active magnesium oxide, dicumyl peroxide, triallyl isocyanurate, plasticizer, antioxidant, 4,4-bis(α,α-dimethylbenzyl)diphenylamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and flame retardant are mixed and then subjected to open refining; and then vulcanized to obtain a twisting and cracking resistant soft cable sheath material for wind power generation.

[0028] In the present invention, the open milling temperature is 60-70° C. The purpose of the open milling is to ensure that the filler is evenly dispersed in the matrix material. The present invention does not impose any particular restrictions on the equipment and specific operations of the open milling, and the open milling equipment and methods commonly used in the art can be used.

[0029] In the present invention, the vulcanization time is 8 to 20 minutes, and the vulcanization temperature is 160 to 195°C. The twist-resistant and crack-resistant flexible cable sheath material for wind power generation of the present invention can be vulcanized over a wide temperature range. When vulcanized within this temperature range, the resulting material has a small rate of change in tensile strength and elongation before and after aging, while maintaining high tensile strength and elongation at break. The vulcanization temperature is more preferably 165 to 180°C. Within this temperature range, the rate of change in tensile strength before and after aging is less than 5%, and the tensile strength before and after aging can be maintained above 12 MPa. At the same time, the elongation at break before aging is greater than 500%, and the elongation at break after aging can still be maintained above 400%. When the vulcanization temperature is too low, the crosslinking reaction rate is insufficient, resulting in a low crosslinking density, which in turn reduces the aging resistance of the cable sheath material and increases the rate of change in tensile strength and elongation at break. When the vulcanization temperature is too high, on the one hand, it will cause over-vulcanization, causing the cross-linking network to break or reorganize, resulting in a significant decrease in mechanical properties; on the other hand, high temperature will accelerate the dehydrochlorination reaction of the chlorinated polyethylene (CPE) matrix, and the free HCl will further catalyze the degradation of the CPE molecular chain, exacerbating the aging and embrittlement of the material.

[0030] In the present invention, the preparation method of the modified carbon black, modified white carbon black and modified active magnesium oxide comprises the following steps: dissolving a silane coupling agent in an ethanol aqueous solution with a pH of 4 to 6 to obtain a mixed solution; The mixed liquid is used to spray carbon black and / or white carbon black and / or active magnesium oxide, and then dried at 70-90° C. for 24-48 hours to obtain modified carbon black, modified white carbon black and modified active magnesium oxide.

[0031] The present invention can use acetic acid to adjust the pH of the ethanol aqueous solution. The present invention does not impose any particular restrictions on the volume fraction of the ethanol aqueous solution, and a volume fraction commonly used in the art can be used. The present invention does not impose any particular restrictions on the above-mentioned spraying treatment, and a spraying method commonly used in the art can be used. In the present invention, the modified carbon black, modified white carbon black, and modified activated magnesium oxide can be mixed and modified simultaneously, or they can be modified separately. The present invention preferably performs the modification simultaneously after mixing to save operating steps.

[0032] The technical solution of the present invention is further described below with reference to specific examples. The present invention has no particular restrictions on the sources of the reagents used in the following examples; commercially available products known to those skilled in the art may be used. The carbon black used in the following examples is high surface area carbon black, model N330.

[0033] Example 1 This embodiment provides a twisting-resistant and cracking-resistant flexible cable sheath material for wind power generation and a preparation method thereof.

[0034] The twisting and cracking resistant flexible cable sheath material for wind power generation provided in this embodiment is made from the following raw materials in parts by weight: 100 parts of chlorinated polyethylene, 25 parts of carbon black, 12 parts of light calcium carbonate, 1 part of white carbon black, 12 parts of talc, 5 parts of active magnesium oxide, 2 parts of diisopropyl benzene peroxide, 1.5 parts of triallyl isocyanurate, 6 parts of plasticizer (including 2 parts of dioctyl sebacate and 4 parts of trioctyl trimellitate), 3 parts of antioxidant (including 2 parts of antioxidant 4010NA and 1 part of antioxidant MBZ), 1 part of 4,4-bis(α,α-dimethylbenzyl)diphenylamine, 2 parts of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4 parts of flame retardant (including 1 part of antimony trioxide and 3 parts of tetrabromobisphenol A).

[0035] The specific preparation method comprises the following steps: (1) Silane coupling agent KH550 was dissolved in a mixed solution of ethanol, water, and acetic acid in a volume ratio of 96:3.5:0.5 to obtain a mixed solution with a mass fraction of 10 wt% of the silane coupling agent. Carbon black, white carbon black, activated magnesium oxide, and antimony trioxide were mixed in a mixer to obtain a mixture. During the mixing process, the mixed solution was sprayed onto the surface of the mixture. The ratio of the mixture to the mixed solution was 20 g:1 mL. After mixing, the mixture was dried at 80°C for 30 h to obtain a modified mixed inorganic filler.

[0036] (2) The modified mixed inorganic filler, chlorinated polyethylene, light calcium carbonate, talc, diisopropylbenzene peroxide, triallyl isocyanurate, plasticizer, antioxidant, 4,4-bis(α,α-dimethylbenzyl)diphenylamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and flame retardant are mixed and then refined in an open mill at a temperature of 65±3°C until the surface is smooth and flat.

[0037] (3) Preheat the mold of the flat vulcanizer to the vulcanization temperature (160°C), then cut the opened film into appropriate sizes and place it in the mold. Slowly close the mold and preheat it for 2 minutes without pressurization. After preheating, fully close the mold and pressurize it, then release the pressure and exhaust it. Finally, completely close the mold and vulcanize it at 160°C for 10 minutes to obtain a torsion-resistant and crack-resistant flexible cable sheath material for wind power generation. The vulcanization pressure during the vulcanization process is 1.5 MPa, the vulcanization speed is 8.5 m / min, and the material thickness is about 1.2 mm.

[0038] Example 2 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 165°C.

[0039] Example 3 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 170°C.

[0040] Example 4 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 175°C.

[0041] Example 5 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 180°C.

[0042] Example 6 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 185°C.

[0043] Example 7 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 190°C.

[0044] Example 8 The difference between this embodiment and embodiment 1 is that the vulcanization temperature is 195°C.

[0045] Example 9 Compared with Example 1, the difference between this embodiment and Example 1 is that the formula of this embodiment is slightly different from that of Example 1.

[0046] The twisting and cracking resistant flexible cable sheath material for wind power generation provided in this embodiment is made from the following raw materials in parts by weight: 100 parts of chlorinated polyethylene, 20 parts of carbon black, 10 parts of light calcium carbonate, 1 part of white carbon black, 10 parts of talc, 4 parts of activated magnesium oxide, 2 parts of diisopropyl benzene peroxide, 1 part of triallyl isocyanurate, 5 parts of plasticizer (including 2 parts of dioctyl sebacate and 3 parts of trioctyl trimellitate), 2 parts of antioxidant (including 1 part of antioxidant 4010NA and 1 part of antioxidant MBZ), 0.5 parts of 4,4-bis(α,α-dimethylbenzyl)diphenylamine, 1 part of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4 parts of flame retardant (including 1 part of antimony trioxide and 3 parts of tetrabromobisphenol A).

[0047] Example 10 Compared with Example 1, the difference between this embodiment and Example 1 is that the formula of this embodiment is slightly different from that of Example 1.

[0048] The twisting and cracking resistant flexible cable sheath material for wind power generation provided in this embodiment is made from the following raw materials in parts by weight: 100 parts of chlorinated polyethylene, 30 parts of carbon black, 15 parts of light calcium carbonate, 2 parts of white carbon black, 15 parts of talc, 6 parts of active magnesium oxide, 3 parts of diisopropyl benzene peroxide, 2 parts of triallyl isocyanurate, 8 parts of plasticizer (including 3 parts of dioctyl sebacate and 5 parts of trioctyl trimellitate), 3 parts of antioxidant (including 2 parts of antioxidant 4010NA and 1 part of antioxidant MBZ), 1 part of 4,4-bis(α,α-dimethylbenzyl)diphenylamine, 3 parts of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 5 parts of flame retardant (including 1 part of antimony trioxide and 4 parts of tetrabromobisphenol A).

[0049] Example 11 This embodiment adopts the formula of Example 1, and produces the cable FDLHEH-1.8 / 3kV-1*300 according to the actual production process of the cable. The equipment used is the German Trost φ60+φ90+φ150 three-layer co-extrusion equipment. The vulcanization pressure is controlled to 1.1 MPa, the vulcanization temperature is 184°C, and the vulcanization speed is changed to verify the aging performance of the sheath material. The vulcanization speeds are 5, 6, 7, and 10 m / min, respectively.

[0050] Comparative Example 1 The difference between this comparative example and Example 11 is that this comparative example adopts a commercially available cable sheath material formula, and the vulcanization speeds are 6 m / min and 7 m / min respectively.

[0051] Test example 1. Aging test The cable sheath materials of the Examples and Comparative Examples were cut into standard dumbbell shapes. Ten samples were cut from each group, five of which were tested for mechanical properties before aging, and five for mechanical properties after aging. The aging conditions for Examples 1-8 and Example 11 were 168 hours in an air oven at 135°C. The aging conditions for Comparative Example 1 were 168 hours in an air oven at 120°C. The test results are summarized in Tables 1 and 2.

[0052] Table 1 Aging performance data of cable sheath materials

[0053] As can be seen in Table 1, the higher the vulcanization temperature, the higher the tensile strength of the resulting material before aging, which initially increases and then decreases, while the elongation at break shows a continuously decreasing trend. After aging, the rate of change in tensile strength is within -15% to +25%, and the absolute value of the rate of change in elongation at break is within 40%, with a minimum of 8%. The cable sheath materials of Examples 2, 3, and 4 (vulcanization temperatures of 165-180°C) exhibit high tensile strength and elongation at break, with low rates of change.

[0054] Table 2 Aging performance data of cable sheath materials of Example 11 and Comparative Example 1

[0055] As can be seen from Table 2, the cable sheath material produced using the actual cable production process exhibits a tensile strength and elongation change rate of approximately 20%. Different vulcanization rates have little effect on the performance of the cable sheath material, demonstrating that this sheath material meets production requirements and has a wide processing window. The cable sheath material of Comparative Example 1 has a lower aging temperature (120°C), but its elongation at break changes by over 40%, indicating that its aging resistance is significantly inferior to that of the cable sheath material of Example 11.

[0056] 2. Ozone resistance test The cable sheath materials of the embodiment and the comparative example were placed in (200±50)×10 -6 Under the experimental conditions of ozone concentration of %, the cracking of the material surface was observed at different times, and the results are summarized in Table 3.

[0057] Table 3 Ozone resistance test results

[0058] It can be seen that the cable sheath material of the embodiment exhibits excellent ozone resistance.

[0059] 3. Room temperature torsion test At room temperature (25±3°C), 12m long finished cables from Example 11 (vulcanization speed 7m / min) and Comparative Example 1 (vulcanization speed 7m / min) were suspended on a rotatable wheel, with the lower portion of the cable secured to a bracket. The wheels were torsionally rotated 1080° clockwise, then counterclockwise by the same angle to return to the original state. This cycle was followed by 1080° counterclockwise, then clockwise by the same angle to return to the original state. Surface cracks were observed after 5000, 5000, and 15000 torsion cycles. The test results are summarized in Table 4.

[0060] Table 4 Results of room temperature torsion test

[0061] It can be seen that the cable sheath material of Example 11 exhibits better room temperature torsion resistance than that of Comparative Example 1.

[0062] 4. Low temperature torsion test At -40°C, 12m long finished cables from Example 11 (vulcanization speed 7m / min) and Comparative Example 1 (vulcanization speed 7m / min) were suspended on a rotatable wheel, with the lower portion of the cable secured to a bracket. The torsion cycle was as follows: the wheel was first twisted 1080° clockwise, then counterclockwise by the same angle to return to the original state. This cycle was followed by a 1080° counterclockwise twist, then a clockwise twist to return to the original state. Surface cracks were observed after 1000, 2000, and 3000 torsion cycles. The test results are summarized in Table 5.

[0063] Table 5 Low temperature torsion test results

[0064] It can be seen that the cable sheath material of Example 11 exhibits more excellent low-temperature torsion resistance than that of Comparative Example 1.

[0065] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A twisting and cracking resistant flexible cable sheath material for wind power generation, characterized in that: It is prepared from the following raw materials in parts by weight: 90-110 parts of chlorinated polyethylene, 20-30 parts of carbon black, 10-15 parts of light calcium carbonate, 1-2 parts of white carbon black, 10-15 parts of talc, 4-6 parts of active magnesium oxide, 2-3 parts of dicumyl peroxide, 1-2 parts of triallyl isocyanurate, 5-8 parts of plasticizer, 2-3 parts of antioxidant, 0.5-1 part of 4,4-bis(α,α-dimethylbenzyl)diphenylamine, 1-3 parts of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 4-5 parts of flame retardant, and 1-2 parts of silane coupling agent.

2. The twisting and cracking resistant flexible cable sheath material for wind power generation according to claim 1, characterized in that: The silane coupling agent includes one or more of KH550, KH560 or KH570.

3. The twisting and cracking resistant flexible cable sheath material for wind power generation according to claim 1, characterized in that: The plasticizer includes dioctyl sebacate and trioctyl trimellitate, and the mass ratio of dioctyl sebacate to trioctyl trimellitate is 1:(1~3).

4. The twisting and cracking resistant flexible cable sheath material for wind power generation according to claim 1, characterized in that: The antioxidants include antioxidant 4010NA and antioxidant MBZ.

5. The twisting and cracking resistant flexible cable sheath material for wind power generation according to claim 4, characterized in that: The mass ratio of antioxidant 4010NA to antioxidant MBZ is (1~3):

1.

6. The twisting and cracking resistant flexible cable sheath material for wind power generation according to claim 1, characterized in that: The flame retardant includes antimony trioxide and tetrabromobisphenol A.

7. The twisting and cracking resistant flexible cable sheath material for wind power generation according to claim 6, characterized in that: The mass ratio of antimony trioxide to tetrabromobisphenol A is 1: (2~5).

8. The method for preparing the twisting and cracking resistant flexible cable sheath material for wind power generation according to any one of claims 1 to 7, characterized in that: The steps include: Carbon black, white carbon black and active magnesium oxide are mixed and then modified with a silane coupling agent to prepare modified carbon black, modified white carbon black and modified active magnesium oxide; Chlorinated polyethylene, modified carbon black, light calcium carbonate, modified white carbon black, talc, modified active magnesium oxide, dicumyl peroxide, triallyl isocyanurate, plasticizer, antioxidant, 4,4-bis(α,α-dimethylbenzyl)diphenylamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and flame retardant are mixed and then subjected to open refining; and then vulcanized to obtain a twisting and cracking resistant soft cable sheath material for wind power generation.

9. The preparation method according to claim 8, wherein The refining temperature is 60~70℃; the vulcanization temperature is 160~195℃, and the vulcanization time is 8~20min.

10. The preparation method according to claim 8, characterized in that The preparation method of the modified carbon black, modified white carbon black and modified active magnesium oxide comprises the following steps: dissolving a silane coupling agent in an ethanol aqueous solution with a pH of 4 to 6 to obtain a mixed solution; The mixed liquid is used to spray carbon black and / or white carbon black and / or active magnesium oxide, and then dried at 70-90° C. for 24-48 hours to obtain modified carbon black, modified white carbon black and modified active magnesium oxide.

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