A high-temperature and high-pressure resistant chlorinated polyvinyl chloride sheath pipe for power cable and a preparation method thereof
By grafting long-chain high-molecular organic compounds onto the surface of mica powder, modified mica powder additives were prepared, which solved the problems of easy softening and deformation and insufficient impact resistance of chlorinated polyvinyl chloride sheathing pipes under high temperature and high pressure. This improved the mechanical strength and flexibility of the material and achieved excellent high temperature resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANTAI WEIYE COMM TECH CO LTD
- Filing Date
- 2026-04-22
- Publication Date
- 2026-07-03
AI Technical Summary
Existing chlorinated polyvinyl chloride sheathing pipes are prone to softening and deformation under high temperature and high pressure environments, and their impact resistance is insufficient, making it difficult to meet the reliability requirements of applications in harsh environments.
Modified mica powder additives are prepared by grafting long-chain high-molecular organic compounds onto the surface of mica powder. These additives form an interwoven and entangled three-dimensional network structure with the matrix, which improves the mechanical interlocking and flexibility of the material and maintains stability at high temperatures.
The mechanical strength and impact performance of the sheath tube under high temperature and high pressure have been improved, and the material is more stable under high temperature conditions, exhibiting excellent high temperature resistance.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of cable technology, specifically relating to a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables and its preparation method. Background Technology
[0002] Chlorinated polyvinyl chloride (PVC) is a product of further chlorination modification of PVC. It possesses excellent electrical insulation properties, as well as outstanding chemical corrosion resistance, flame retardancy, self-extinguishing properties, and weather resistance. Based on these characteristics, chlorinated PVC is widely recognized as an ideal material for buried high-voltage power cable sheathing and has been widely used for cable protection in urban power grid renovation, municipal engineering, road and bridge construction, and other fields.
[0003] However, chlorinated polyvinyl chloride (PVC) still faces a series of technical challenges in practical applications, which constitute the main shortcomings of existing technologies: First, although chlorinated PVC has better heat resistance than polyvinyl chloride (PVC), high-voltage power cables generate Joule heat during operation, especially under heavy load or fault conditions, where the cable conductor temperature rises significantly. If the sheath material is not heat-resistant enough, it will soften and deform, losing its protective function for the cable. Therefore, chlorinated PVC still cannot meet the requirements of practical applications. Second, chlorinated PVC has insufficient impact resistance. Although chlorinated PVC has high rigidity, its toughness is poor, exhibiting brittle fracture at low temperatures and easily breaking under external impact. This defect limits the reliability of chlorinated PVC sheaths in relatively harsh environments. In existing technologies, impact modifiers are often added to improve toughness, but the introduction of modifiers often negatively affects the material's heat resistance and rigidity, creating a technical bottleneck of "rigidity-toughness contradiction."
[0004] In summary, developing a chlorinated polyvinyl chloride (PVC) power cable sheath with both excellent high-temperature resistance and high impact strength has become an urgent technical problem to be solved in this field. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables and its preparation method.
[0006] A first aspect of the present invention provides a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables, which is made from the following raw materials measured in parts by weight: Chlorinated polyvinyl chloride: 85-98 parts; Polyvinyl chloride: 18-25 parts; Modified mica powder additive: 2.4-6.5 parts; Lubricant: 1-1.5 parts; Stabilizer: 3-6 parts; Antioxidant: 0.5-1 part; The modified mica powder additive is prepared by grafting long-chain high-molecular organic compounds onto the surface of mica powder.
[0007] As a preferred embodiment of the present invention, the preparation method of the modified mica powder additive includes the following steps: Step 1: Preparation of organically modified mica powder Mica powder was added to toluene, and ultrasound was turned on. After a uniform dispersion was formed, an organic modifier and a catalyst were added to the dispersion. After the addition was complete, the temperature was raised to 90-100℃ and kept constant while stirring for 6-9 hours. Heating was then stopped, the material was cooled and discharged, and the collected crude product was washed and vacuum dried to obtain organically modified mica powder. Step 2: Preparation of modified mica powder additive Organically modified mica powder was dispersed in tetrahydrofuran. Then, a linker and a photoinitiator were added to the resulting dispersion. After the addition was complete, stirring was started and the mixture was thoroughly mixed. The mixture was then irradiated with a 365 nm ultraviolet lamp and stirred at room temperature for 0.5-1 h. 1,1,3,3-Tetramethyl-1,3-bis[2-(5-norbornen-2-yl)ethyl]disiloxane was then added. After the addition was complete, stirring was continued for 3-6 h. The mixture was then discharged, and the separated solid material was washed and dried to obtain the modified mica powder additive.
[0008] As a preferred embodiment of the present invention, in step one, the organic modifier is methacrylic acid or acrylic acid.
[0009] As a preferred embodiment of the present invention, in step one, the catalyst is aminosulfonic acid or p-toluenesulfonic acid.
[0010] As a preferred embodiment of the present invention, in step two, the connecting reagent is bis(3-mercaptopropionic acid) ethylene glycol or bis(mercaptoacetic acid)-1,4-butanediol.
[0011] As a preferred technical solution of the present invention, in step two, the photoinitiator is any one of photoinitiator 184, photoinitiator 1173, or photoinitiator TPO.
[0012] As a preferred embodiment of the present invention, in step two, the mass ratio of the organically modified mica powder, the connecting agent, and 1,1,3,3-tetramethyl-1,3-bis[2-(5-norbornene-2-yl)ethyl]disiloxane is 1:0.15-0.25:0.2-0.35.
[0013] It should be noted that in the above technical solution, a catalyst is first used to perform surface organic modification of mica powder using an organic modifier. Unsaturated alkenyl substituents are modified on the surface of the mica powder to obtain organically modified mica powder. Then, under the combined action of ultraviolet light and a photoinitiator, the unsaturated alkenyl substituents of the organically modified mica powder can undergo a click reaction with the thiol functional group at one end of the reagent structure, while the thiol substituent at the other end can further react with 1,1,3,3-tetramethyl-1,3 The unsaturated alkenyl substituents of 1,1,3,3-tetramethyl-1,3-bis[2-(5-norbornen-2-yl)ethyl]disiloxane undergo a click polymerization reaction, forming an in-situ click polymerization reaction of the unsaturated alkenyl substituents of the organically modified mica powder as active initiation sites. This reaction initiates the linking agent and 1,1,3,3-tetramethyl-1,3-bis[2-(5-norbornen-2-yl)ethyl]disiloxane on the surface of the mica powder, thereby grafting long-chain high-molecular-weight organic compounds onto the surface of the mica powder to obtain a modified mica powder additive.
[0014] As a preferred embodiment of the present invention, the lubricant is any one of polyethylene wax, stearic acid, zinc stearate, or calcium stearate.
[0015] As a preferred embodiment of the present invention, the stabilizer is a calcium-zinc stabilizer or a barium-zinc stabilizer; the antioxidant is antioxidant 1010 or antioxidant 1076.
[0016] A second aspect of the present invention provides a method for preparing a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables, comprising the following steps: Step 1: Mixing materials After weighing and preparing all the raw materials according to the specified weight proportions, put them into a high-speed mixer, control the speed to 100-300 r / min, and mechanically stir until they are evenly mixed to obtain a premix. The second step is to feed the premixed material into the twin-screw extruder through the feed port, extrude and granulate it, then transfer the masterbatch to the extruder for extrusion molding, and wait for it to cool and solidify.
[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention prepares a modified mica powder additive by grafting long-chain polymeric organic compounds onto the surface of mica powder. Using this additive, on the one hand, the thiol groups in the long-chain polymeric organic compound structure interact with the matrix during melt extrusion, promoting the formation of an interwoven, three-dimensional network structure between the polymeric organic compound and the matrix molecular chains. This structure creates an organic transition layer between the mica powder and the matrix, forming a mechanically interlocking "mortise and tenon" effect, allowing the mica powder to be more evenly distributed in the material, fully leveraging the modification advantages and improving material strength. On the other hand, the long-chain polymeric organic compound structure contains flexible segments, improving the material's flexibility and impact resistance. Furthermore, the rigid cyclic structure and high-bond-energy silicon-oxygen bonds in the long-chain polymeric organic compound structure make the network structure more stable under high-temperature conditions, thereby improving the material's high-temperature resistance. Detailed Implementation
[0018] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.
[0019] Example 1
[0020] This embodiment provides a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables, which is made from the following raw materials measured in parts by weight: Chlorinated polyvinyl chloride: 85 parts; Polyvinyl chloride: 18 parts; Modified mica powder additive: 2.4 parts; Zinc stearate: 1 part; Calcium and zinc stabilizer: 3 parts; Antioxidant 1010: 0.5 parts; The method for preparing the sheath tube includes the following steps: Step 1: Mixing materials After weighing and preparing all the raw materials according to the specified weight proportions, put them into a high-speed mixer, control the speed at 100 r / min, and mechanically stir until they are evenly mixed to obtain a premix. The second step is to feed the premixed material into the twin-screw extruder through the feed port, extrude and granulate it, then transfer the masterbatch to the extruder for extrusion molding, and wait for it to cool and solidify.
[0021] The preparation method of the modified mica powder additive includes the following steps: Step 1: Preparation of organically modified mica powder Add 2.8g of mica powder to toluene, turn on the sonication, and wait for a uniform dispersion to form. Then add 0.4g of methacrylic acid and 0.1g of p-toluenesulfonic acid to the dispersion. After the addition is complete, turn on the heating and wait for the temperature to rise to 95℃. Keep the temperature constant and continue stirring for 8 hours. Stop heating, cool down and discharge the material. The collected crude product is washed and vacuum dried to obtain organic modified mica powder. Step 2: Preparation of modified mica powder additive 1.8g of organically modified mica powder was dispersed in tetrahydrofuran. Then, 0.4g of bis(3-mercaptopropionic acid) ethylene glycol and photoinitiator 184 were added to the resulting dispersion. After the addition was complete, stirring was started and the mixture was mixed. The mixture was then irradiated with a 365nm ultraviolet lamp and stirred at room temperature for 0.5h. Then, 0.45g of 1,1,3,3-tetramethyl-1,3-bis[2-(5-norbornene-2-yl)ethyl]disiloxane was added. After the addition was complete, stirring was continued for 4h. The mixture was then discharged, and the separated solid material was washed and dried to obtain the modified mica powder additive.
[0022] Example 2
[0023] This embodiment provides a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables, which is made from the following raw materials measured in parts by weight: Chlorinated polyvinyl chloride: 90 parts; Polyvinyl chloride: 20 parts; Modified mica powder additive: 6 parts; Calcium stearate: 1.2 parts; Barium-zinc stabilizer: 4 parts; Antioxidant 1010: 0.8 parts; The method for preparing the sheath tube includes the following steps: Step 1: Mixing materials After weighing and preparing all the raw materials according to the specified weight proportions, put them into a high-speed mixer, control the speed at 200 r / min, and mechanically stir until they are evenly mixed to obtain a premix. The second step is to feed the premixed material into the twin-screw extruder through the feed port, extrude and granulate it, then transfer the masterbatch to the extruder for extrusion molding, and wait for it to cool and solidify.
[0024] The preparation method of the modified mica powder additive is the same as that in Example 1.
[0025] Example 3
[0026] This embodiment provides a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables, which is made from the following raw materials measured in parts by weight: Chlorinated polyvinyl chloride: 98 parts; Polyvinyl chloride: 25 parts; Modified mica powder additive: 6.5 parts; Zinc stearate: 1.5 parts; Barium-zinc stabilizer: 6 parts; Antioxidant 1076: 1 part; The method for preparing the sheath tube includes the following steps: Step 1: Mixing materials After weighing and preparing all the raw materials according to the specified weight proportions, put them into a high-speed mixer, control the speed at 300 r / min, and mechanically stir until they are evenly mixed to obtain a premix. The second step is to feed the premixed material into the twin-screw extruder through the feed port, extrude and granulate it, then transfer the masterbatch to the extruder for extrusion molding, and wait for it to cool and solidify.
[0027] The preparation method of the modified mica powder additive is the same as that in Example 1.
[0028] Comparative Example 1
[0029] The difference between this comparative example and Example 2 is that the modified mica powder additive was replaced with unmodified mica powder; all other aspects are the same.
[0030] Comparative Example 2
[0031] The difference between this comparative example and Example 2 is that the modified mica powder additive is removed, while the rest are the same.
[0032] The premixes provided in the above embodiments and comparative examples were extruded to form test samples that met the specifications, and the following performance tests were conducted: (1) Tensile properties were tested according to standard GB / T 1040.1-2025, with the tensile rate controlled at 10 mm / min; (2) Impact performance test shall be conducted in accordance with standard GB / T 1843-2008; (3) High temperature resistance test: The test sample is placed in an oven at 150℃ and heat-treated for 24 hours. The sample surface phenomenon is observed and the high temperature resistance of the sample is evaluated.
[0033] The performance test data above are shown in Table 1.
[0034] Table 1 Performance Test Results
[0035] As can be seen from the above, the sheath tube prepared in the embodiments of the present invention can exhibit excellent strength, impact toughness, and high temperature resistance in practical applications. When the modified mica powder additive is replaced with unmodified mica powder, the mica powder struggles to form a stable mechanical intercalation system and cannot be uniformly dispersed, making it difficult to efficiently exert its reinforcing advantages. Simultaneously, it loses the modification effect of long-chain polymeric organic compounds, resulting in a significant decrease in all properties of the material.
[0036] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.
Claims
1. A chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables, characterized in that, It is made from the following raw materials, measured in parts by weight: Chlorinated polyvinyl chloride: 85-98 parts; Polyvinyl chloride: 18-25 parts; Modified mica powder additive: 2.4-6.5 parts; Lubricant: 1-1.5 parts; Stabilizer: 3-6 parts; Antioxidant: 0.5-1 part; The modified mica powder additive is prepared by grafting long-chain high-molecular organic compounds onto the surface of mica powder.
2. The chlorinated polyvinyl chloride sheathing for high-temperature and high-voltage power cables according to claim 1, characterized in that, The preparation method of the modified mica powder additive includes the following steps: Step 1: Preparation of organically modified mica powder Mica powder was added to toluene, and ultrasound was turned on. After a uniform dispersion was formed, an organic modifier and a catalyst were added to the dispersion. After the addition was complete, the temperature was raised to 90-100℃ and kept constant while stirring for 6-9 hours. Heating was then stopped, the material was cooled and discharged, and the collected crude product was washed and vacuum dried to obtain organically modified mica powder. Step 2: Preparation of modified mica powder additive Organically modified mica powder was dispersed in tetrahydrofuran. Then, a linker and a photoinitiator were added to the resulting dispersion. After the addition was complete, stirring was started and the mixture was thoroughly mixed. The mixture was then irradiated with a 365 nm ultraviolet lamp and stirred at room temperature for 0.5-1 h. 1,1,3,3-Tetramethyl-1,3-bis[2-(5-norbornen-2-yl)ethyl]disiloxane was then added. After the addition was complete, stirring was continued for 3-6 h. The mixture was then discharged, and the separated solid material was washed and dried to obtain the modified mica powder additive.
3. The chlorinated polyvinyl chloride sheathing for high-temperature and high-voltage power cables according to claim 2, characterized in that, In step one, the organic modifier is methacrylic acid or acrylic acid.
4. The chlorinated polyvinyl chloride sheathing for high-temperature and high-voltage power cables according to claim 2, characterized in that, In step one, the catalyst is aminosulfonic acid or p-toluenesulfonic acid.
5. The chlorinated polyvinyl chloride sheathing for high-temperature and high-voltage power cables according to claim 2, characterized in that, In step two, the connecting reagent is bis(3-mercaptopropionic acid) ethylene glycol or bis(mercaptoacetic acid)-1,4-butanediol.
6. The chlorinated polyvinyl chloride sheathing for high-temperature and high-voltage power cables according to claim 2, characterized in that, In step two, the photoinitiator is any one of photoinitiator 184, photoinitiator 1173, or photoinitiator TPO.
7. The chlorinated polyvinyl chloride sheathing pipe for high-temperature and high-voltage power cables according to claim 2, characterized in that, In step two, the mass ratio of the organically modified mica powder, the connecting agent, and 1,1,3,3-tetramethyl-1,3-bis[2-(5-norbornene-2-yl)ethyl]disiloxane is 1:0.15-0.25:0.2-0.
35.
8. The chlorinated polyvinyl chloride sheathing pipe for high-temperature and high-voltage power cables according to claim 1, characterized in that, The lubricant is any one of polyethylene wax, stearic acid, zinc stearate, or calcium stearate.
9. The chlorinated polyvinyl chloride sheathing for high-temperature and high-voltage power cables according to claim 1, characterized in that, The stabilizer is a calcium-zinc stabilizer or a barium-zinc stabilizer; the antioxidant is antioxidant 1010 or antioxidant 1076.
10. A method for preparing a chlorinated polyvinyl chloride sheath for high-temperature and high-voltage power cables as described in claim 1, characterized in that, Includes the following steps: Step 1: Mixing materials After weighing and preparing all the raw materials according to the specified weight proportions, put them into a high-speed mixer, control the speed to 100-300 r / min, and mechanically stir until they are evenly mixed to obtain a premix. The second step is to feed the premixed material into the twin-screw extruder through the feed port, extrude and granulate it, then transfer the masterbatch to the extruder for extrusion molding, and wait for it to cool and solidify.