Low-voltage power cable

Abstract

The invention relates to the technical field of power cables, and provides a low-voltage power cable which comprises a conductor, an insulating layer and a sheath layer which are sequentially arranged from inside to outside, and the sheath layer is prepared from, by weight, 100 parts of ethylene-vinyl acetate copolymer, 30-35 parts of high-density polyethylene, 20-30 parts of low-density polyethylene copolymer, 8-10 parts of compatilizer and 40-50 parts of auxiliaries. The low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer, a polymeric monomer of the low-density polyethylene copolymer is butyl acrylate, and the butyl acrylate content of the first low-density polyethylene copolymer is different from that of the second low-density polyethylene copolymer. According to the technical scheme, the problem of insufficient strength of the low-voltage power cable in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and more specifically, to a low-voltage power cable. Background Technology

[0002] Low-voltage power cables are common power equipment used for transmitting and distributing low-voltage electrical energy. They are widely used in urban power grids, building power distribution, industrial and mining enterprises, infrastructure and civil power supply, and are usually composed of conductors, insulation layers and sheath layers.

[0003] Currently, traditional low-voltage power cable sheath materials mostly use polyolefin-based substrates. While these materials possess certain insulation and processability, they generally suffer from insufficient mechanical strength and poor toughness. Power cables with insufficient strength are prone to sheath layer cracking, damage, deformation, and aging and peeling under long-term use or external forces. This not only reduces the cable's service life but can also lead to insulation layer exposure, moisture absorption, and damage, potentially causing safety hazards such as leakage and short circuits. In severe cases, it can even result in power outages, equipment damage, and personal injury accidents.

[0004] Therefore, it is necessary to develop a high-strength low-voltage power cable. Summary of the Invention

[0005] This invention proposes a low-voltage power cable that solves the problem of insufficient strength in low-voltage power cables in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes a low-voltage power cable, comprising a conductor, an insulation layer, and a sheath layer arranged sequentially from the inside out. The sheath layer comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 30-35 parts of high-density polyethylene, 20-30 parts of low-density polyethylene copolymer, 8-10 parts of compatibilizer, and 40-50 parts of additives. The low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer. The monomer of the low-density polyethylene copolymer is butyl acrylate, and the butyl acrylate content of the first low-density polyethylene copolymer and the second low-density polyethylene copolymer is different.

[0007] As a further technical solution, the conductor is made of copper.

[0008] As a further technical solution, the insulation layer is a cross-linked polyethylene insulation layer.

[0009] As a further technical solution, the butyl acrylate content of the first low-density polyethylene copolymer is 7wt%, and the butyl acrylate content of the second low-density polyethylene copolymer is 17wt%.

[0010] As a further technical solution, the mass ratio of the first low-density polyethylene copolymer to the second low-density polyethylene copolymer is 9~10:6.

[0011] As a further technical solution, the compatibilizer includes one or two of maleic anhydride-grafted polyethylene and maleic anhydride-grafted polypropylene, preferably maleic anhydride-grafted polyethylene.

[0012] As a further technical solution, the additive is composed of flame retardant, filler, antioxidant and lubricant in a mass ratio of 15~20:15~20:1~3:4~6.

[0013] As a further technical solution, the flame retardant includes one or two of magnesium hydroxide and aluminum hydroxide, preferably aluminum hydroxide.

[0014] As a further technical solution, the filler includes one or more of calcium carbonate, talc, and carbon black.

[0015] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076, preferably antioxidant 1010.

[0016] As a further technical solution, the lubricant includes one or two of stearic acid and zinc stearate, preferably stearic acid.

[0017] As a further technical solution, the calcium carbonate is modified calcium carbonate, and the modifier of the modified calcium carbonate is composed of allyltrimethoxysilane and methacryloxysilane coupling agent in a mass ratio of 1:2~4.

[0018] In the low-voltage power cable of this invention, the modifier for modified calcium carbonate is composed of allyltrimethoxysilane and methacryloxysilane coupling agents. The silicon-oxygen bonds formed by allyltrimethoxysilane can form a stable chemical bond with the hydroxyl groups on the surface of calcium carbonate, enhancing the interfacial anchoring effect between the inorganic filler and the organic matrix, and improving the interfacial bonding strength. The introduced allyl double bonds can participate in the crosslinking and entanglement of the matrix resin, improving the interfacial stability. The methacryloxysilane introduces methacryloxy groups with higher compatibility with matrix resins such as polyethylene and ethylene-vinyl acetate copolymer, making it easier to form covalent bonds and network structures with polymer chains, improving interfacial adhesion strength and reducing interfacial defects, effectively improving the strength of the low-voltage power cable.

[0019] As a further technical solution, the methacryloyloxysilane coupling agent includes one or two of 3-(isobutenoyloxy)propyltrimethoxysilane and 3-methacryloyloxypropylmethyldimethoxysilane.

[0020] As a further technical solution, the preparation method of the modified calcium carbonate includes the following steps: dispersing the modifier in a solvent, adding calcium carbonate, stirring and drying to obtain the modified calcium carbonate.

[0021] As a further technical solution, the solvent is composed of anhydrous ethanol and water in a mass ratio of 5:1.

[0022] As a further technical solution, the stirring time is 1 to 3 hours, preferably 2 hours.

[0023] As a further technical solution, the mass ratio of the solvent to calcium carbonate is 3~6:1, preferably 5:1.

[0024] As a further technical solution, the mass ratio of the modifier to the calcium carbonate is 4~5:50.

[0025] This invention also proposes a method for manufacturing a low-voltage power cable, comprising the following steps: S1. After extruding an insulating layer onto the conductor, a semi-finished product is obtained; S2. Mix the sheath material evenly and extrude it onto the semi-finished product to obtain the low-voltage power cable.

[0026] The working principle and beneficial effects of this invention are as follows: In this invention, a first low-density polyethylene copolymer and a second low-density polyethylene copolymer with different butyl acrylate contents are added to the sheath layer. These two copolymers work synergistically to effectively improve the strength of the low-voltage power cable. The low-density polyethylene copolymers with different butyl acrylate contents differ in polarity, molecular chain flexibility, and interfacial compatibility. The low-density polyethylene copolymer with a higher butyl acrylate content has better interfacial bonding with polar matrices such as ethylene-vinyl acetate copolymers, but its strength is insufficient. The low-density polyethylene copolymer with a lower butyl acrylate content has weaker polarity, more regular molecular chains, and sufficient strength. Through synergy, the high butyl acrylate content component preferentially forms a strong interfacial bond with the ethylene-vinyl acetate copolymer and compatibilizer, improving the interfacial adhesion between the matrix and the polyethylene phase and eliminating interfacial voids and weak areas. The low butyl acrylate content component has higher crystallinity, forming a microcrystalline reinforcement structure within the material to bear external loads. The two copolymers form an interpenetrating network that can uniformly distribute stress, avoiding cracking and fracture caused by stress concentration, and improving the strength of the low-voltage power cable. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples: Ethylene-vinyl acetate copolymer: Model number UE2803; High-density polyethylene: Model number DGDA6098; First low-density polyethylene copolymer: model A2910M; Second low-density polyethylene copolymer: Model A2700M; Maleic anhydride-grafted polyethylene: Model number E204; Calcium carbonate: average particle size is 400 mesh.

[0029] Example 1 The sheath layer comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 30 parts of high-density polyethylene, 20 parts of low-density polyethylene copolymer, 8 parts of maleic anhydride grafted polyethylene, and 40 parts of additives. The additives consist of aluminum hydroxide, calcium carbonate, antioxidant 1010, and stearic acid in a mass ratio of 15:15:1:4. The low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer in a mass ratio of 3:2. A method for manufacturing a low-voltage power cable includes the following steps: S1. After extruding a cross-linked polyethylene insulation layer over a copper conductor, a semi-finished product is obtained; S2. Mix the raw materials for the sheath layer evenly and extrude them onto the outside of the semi-finished product to obtain a low-voltage power cable.

[0030] Example 2 The sheath layer comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 32 parts of high-density polyethylene, 25 parts of low-density polyethylene copolymer, 9 parts of maleic anhydride grafted polyethylene, and 45 parts of additives. The additives consist of aluminum hydroxide, calcium carbonate, antioxidant 1010, and stearic acid in a mass ratio of 18:18:2:5. The low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer in a mass ratio of 3:2. A method for manufacturing a low-voltage power cable includes the following steps: S1. After extruding a cross-linked polyethylene insulation layer over a copper conductor, a semi-finished product is obtained; S2. Mix the raw materials for the sheath layer evenly and extrude them onto the outside of the semi-finished product to obtain a low-voltage power cable.

[0031] Example 3 The sheath layer comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 35 parts of high-density polyethylene, 30 parts of low-density polyethylene copolymer, 10 parts of maleic anhydride-grafted polyethylene, and 50 parts of additives. The additives consist of aluminum hydroxide, calcium carbonate, antioxidant 1010, and stearic acid in a mass ratio of 20:20:3:6. The low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer in a mass ratio of 3:2. A method for manufacturing a low-voltage power cable includes the following steps: S1. After extruding a cross-linked polyethylene insulation layer over a copper conductor, a semi-finished product is obtained; S2. Mix the raw materials for the sheath layer evenly and extrude them onto the outside of the semi-finished product to obtain a low-voltage power cable.

[0032] Example 4 The difference between Example 4 and Example 2 is that the low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer in a mass ratio of 5:3.

[0033] Example 5 The difference between Example 5 and Example 4 is that calcium carbonate is replaced with an equal amount of modified calcium carbonate prepared by the following preparation method; The preparation method of modified calcium carbonate includes the following steps: 4 parts of modifier are dispersed in 500 parts of solvent, 50 parts of calcium carbonate are added, and the mixture is stirred for 2 hours and then dried to obtain modified calcium carbonate. The solvent is composed of anhydrous ethanol and water in a mass ratio of 5:1. The modifier is composed of allyltrimethoxysilane and 3-(isobutenoyloxy)propyltrimethoxysilane in a mass ratio of 1:2.

[0034] Example 6 The difference between Example 6 and Example 5 is that the amount of modifier added is 5 parts.

[0035] Example 7 The difference between Example 7 and Example 6 is that the modifier consists of allyltrimethoxysilane and 3-(isobutenoyloxy)propyltrimethoxysilane in a mass ratio of 1:4.

[0036] Example 8 The difference between Example 6 and Example 8 is that 3-(isobutenoyloxy)propyltrimethoxysilane is replaced with an equal amount of 3-methacryloyloxypropylmethyldimethoxysilane.

[0037] Example 9 The difference between Example 6 and Example 9 is that 3-(isobutenoyloxy)propyltrimethoxysilane is replaced with an equal amount of 3-aminopropyltriethoxysilane.

[0038] Example 10 The difference between Example 10 and Example 6 is that the modifier is allyltrimethoxysilane.

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the low-density polyethylene copolymer is a first low-density polyethylene copolymer.

[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the low-density polyethylene copolymer is a second low-density polyethylene copolymer.

[0041] Experimental Example 1 The sheath of the low-voltage power cables prepared in Examples 1-10 and Comparative Examples 1-3 was tested according to the test methods specified in GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Cables Part 11: General Test Methods - Measurement of Thickness and Dimensions - Mechanical Properties Test". The tensile strength of the specimen was tested. Specimen preparation: The sheath was cut along the cable axis, and a narrow strip was cut to make a small dumbbell specimen with a thickness of 2.0 mm, which is the specimen to be tested.

[0042] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-10 and Comparative Examples 1-3

[0043] Table 1 shows that when the low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer with different butyl acrylate contents, the strength of the low-voltage power cable can be improved. When calcium carbonate is modified using allyltrimethoxysilane and methacryloxysilane coupling agents, the resulting low-voltage power cable exhibits even better strength.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-voltage power cable, comprising a conductor, an insulation layer, and a sheath layer arranged sequentially from the inside out, characterized in that, The sheath layer comprises the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer, 30-35 parts of high-density polyethylene, 20-30 parts of low-density polyethylene copolymer, 8-10 parts of compatibilizer, and 40-50 parts of additives. The monomer of the low-density polyethylene copolymer is butyl acrylate. The low-density polyethylene copolymer is composed of a first low-density polyethylene copolymer and a second low-density polyethylene copolymer, and the butyl acrylate content of the first low-density polyethylene copolymer and the second low-density polyethylene copolymer is different.

2. A low-voltage power cable according to claim 1, characterized in that, The conductor is made of copper.

3. A low-voltage power cable according to claim 1, characterized in that, The insulation layer is a cross-linked polyethylene insulation layer.

4. A low-voltage power cable according to claim 1, characterized in that, The first low-density polyethylene copolymer has a butyl acrylate content of 7 wt%, and the second low-density polyethylene copolymer has a butyl acrylate content of 17 wt%.

5. A low-voltage power cable according to claim 1, characterized in that, The mass ratio of the first low-density polyethylene copolymer to the second low-density polyethylene copolymer is 9~10:

6.

6. A low-voltage power cable according to claim 1, characterized in that, The compatibilizer includes one or both of maleic anhydride-grafted polyethylene and maleic anhydride-grafted polypropylene.

7. A low-voltage power cable according to claim 1, characterized in that, The additives consist of flame retardants, fillers, antioxidants, and lubricants in a mass ratio of 15~20:15~20:1~3:4~6.

8. A low-voltage power cable according to claim 7, characterized in that, The flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide; The filler includes one or more of calcium carbonate, talc, and carbon black; The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076; The lubricant includes one or both of stearic acid and zinc stearate.

9. A low-voltage power cable according to claim 8, characterized in that, The calcium carbonate is modified calcium carbonate, and the modifier of the modified calcium carbonate is composed of allyltrimethoxysilane and methacryloxysilane coupling agent in a mass ratio of 1:2~4.

10. A low-voltage power cable according to claim 9, characterized in that, The methacryloyloxysilane coupling agent includes one or two of 3-(isobutenoyloxy)propyltrimethoxysilane and 3-methacryloyloxypropylmethyldimethoxysilane.

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