High strength power cable and method of making same

Abstract

This invention relates to the field of power cable technology, and proposes a high-strength power cable and its manufacturing method. A high-strength power cable includes 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 PVC resin, 30-35 parts plasticizer, 20-25 parts filler, 4-6 parts stabilizer, and 5-6 parts additives. The filler is composed of acicular wollastonite and flake talc powder in a mass ratio of 6-7:4. The aspect ratio of the acicular wollastonite is 8-13:1, the average particle size of the acicular wollastonite is 1000-1250 mesh, and the average particle size of the flake talc powder is 4000-5000 mesh. This technical solution solves the problem of insufficient strength in power cables in related technologies.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, specifically to a high-strength power cable and its manufacturing method. Background Technology

[0002] Power cables are the core carriers used in power systems for transmitting and distributing electrical energy. They are typically composed of a conductor, an insulation layer, and a sheath. With their advantages of high transmission efficiency, flexible installation, and small footprint, they are widely used in various fields such as industrial production, urban power grids, high-rise buildings, rail transit, and new energy power generation.

[0003] In practical applications, power cables often need to withstand mechanical stresses such as tension, bending, and compression during the laying process. Therefore, the mechanical strength of the sheath and the overall structure is one of the key performance indicators that determines the service life and operational safety of power cables. Traditional power cables still have insufficient strength.

[0004] Insufficient strength in power cables can lead to cracking and damage to the sheath during laying and construction, resulting in exposed insulation layers, short circuits, leakage, and other safety hazards. This can also affect the stability of power transmission, shorten the cable's service life, and increase the maintenance costs and downtime losses of the power system.

[0005] Therefore, it is very necessary to develop a high-strength power cable. Summary of the Invention

[0006] This invention proposes a high-strength power cable and its manufacturing method, which solves the problem of insufficient strength of power cables in related technologies.

[0007] The technical solution of the present invention is as follows: The present invention proposes a high-strength 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 PVC resin, 30-35 parts of plasticizer, 20-25 parts of filler, 4-6 parts of stabilizer, and 5-6 parts of additives. The filler is composed of acicular wollastonite and flaky talc powder in a mass ratio of 6-7:4. The aspect ratio of the acicular wollastonite is 8-13:1, the average particle size of the acicular wollastonite is 1000-1250 mesh, and the average particle size of the flaky talc powder is 4000-5000 mesh.

[0008] As a further technical solution, the conductor is made of copper.

[0009] As a further technical solution, the insulation layer is a cross-linked polyethylene insulation layer.

[0010] As a further technical solution, the plasticizer includes one or more of dioctyl phthalate, diisononyl phthalate, and trioctyl trimellitate.

[0011] In the high-strength power cable of this invention, a plasticizer is added to the sheath layer. Because the PVC resin molecular chains are highly polar and have strong intermolecular forces, the unplasticized PVC melt has high viscosity and poor fluidity, making it difficult to form a continuous and dense cable sheath layer through extrusion. The plasticizer molecules can insert between the PVC resin molecular chains, weaken the attraction between the molecular chains, reduce the melt viscosity, and enable the PVC resin to have good plasticity and fluidity at the processing temperature. It can also promote the uniform dispersion of fillers, stabilizers and other components in the PVC matrix, avoid stress concentration points caused by uneven dispersion, and lay the foundation for improving the mechanical strength of the sheath layer.

[0012] As a further technical solution, the stabilizer includes one or two of calcium-zinc stabilizers and barium-zinc stabilizers, preferably calcium-zinc stabilizers.

[0013] In the high-strength power cable of this invention, a stabilizer is added to the sheath layer. Because PVC resin is prone to dehydrochlorination reaction during high-temperature plasticization and extrusion processing, it causes molecular chain breakage and cross-linking, resulting in resin discoloration and embrittlement, which directly damages the mechanical properties of the sheath layer. The addition of the stabilizer can efficiently capture the hydrogen chloride free radicals generated by PVC degradation, block the chain reaction of degradation, enhance the thermal stability of molecular chains, and improve the service life and operational safety of the power cable.

[0014] As a further technical solution, the additive is composed of antioxidants, UV stabilizers and flame retardants in a mass ratio of 1:1:4~6.

[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 UV absorber includes one or more of UV absorber UV-531, UV absorber UV-327, and UV absorber UV-326, preferably UV absorber UV-531.

[0017] In this invention, an antioxidant and a UV stabilizer are added to the sheath layer of the high-strength power cable. The antioxidant can slow down the oxidative aging process of the sheath layer, preventing safety hazards such as insulation exposure and short circuits caused by sheath layer brittleness during long-term use. The addition of the UV stabilizer can effectively block ultraviolet radiation, block the photodegradation path of PVC, maintain the long-term mechanical properties of the sheath layer, and extend the service life of the cable.

[0018] As a further technical solution, the flame retardant includes one or more of magnesium hydroxide, aluminum hydroxide, and antimony trioxide, preferably antimony trioxide.

[0019] As a further technical solution, the calcium-zinc stabilizer is composed of a first calcium-zinc stabilizer and a second calcium-zinc stabilizer, wherein the ash content of the first calcium-zinc stabilizer and the second calcium-zinc stabilizer are different.

[0020] As a further technical solution, the ash content of the first calcium-zinc stabilizer is 15wt%~25wt%, the ash content of the second calcium-zinc stabilizer is 30wt%~40wt%, and the mass ratio of the first calcium-zinc stabilizer to the second calcium-zinc stabilizer is 2~3:1.

[0021] This invention also proposes a method for preparing a high-strength power cable, comprising the following steps: S1. After extruding an insulating layer onto the conductor, a semi-finished product is obtained; S2. Mix the PVC resin, the plasticizer and the first calcium-zinc stabilizer for a first mixing process, then add filler, additives and the second calcium-zinc stabilizer and mix for a second mixing process to obtain a mixture. S3. The mixture is extruded onto the semi-finished product to obtain the high-strength power cable.

[0022] As a further technical solution, the first mixing time is 10-12 minutes, preferably 10 minutes, and the second mixing time is 15-20 minutes, preferably 15 minutes.

[0023] In the high-strength power cable of this invention, the calcium-zinc stabilizer is composed of a first calcium-zinc stabilizer and a second calcium-zinc stabilizer with different ash contents. The first calcium-zinc stabilizer has an ash content of 15wt%~25wt%, which is relatively low. When added during the initial mixing, it has better compatibility with PVC resin and plasticizers. It can quickly and evenly penetrate into the gaps between PVC molecular chains by taking advantage of the good dispersibility of the low-ash stabilizer, effectively suppressing the problem of local thermal degradation caused by uneven dispersion of the stabilizer. When the filler and additives are added, the second calcium-zinc stabilizer with a higher ash content is added. During this process, heat is generated due to friction and increased viscosity. As the temperature rises, PVC resin is at risk of dehydrochlorination degradation and molecular chain breakage. The calcium-zinc stabilizer with a high ash content has a stronger thermal stability effect and can quickly capture hydrogen chloride free radicals generated under high temperature conditions, blocking the chain reaction of degradation reaction, maximizing the continuity and integrity of PVC molecular chains, and improving the strength of the power cable.

[0024] The working principle and beneficial effects of this invention are as follows: In this invention, a high-strength power cable uses acicular wollastonite and flake talc as fillers. Acicular wollastonite has a suitable aspect ratio of 8-13:1 and a fibrous structure. After being uniformly dispersed in the PVC matrix, it forms an interwoven skeletal support network, effectively bearing and transmitting external mechanical stress. The flake talc has a layered structure; its interlayer slip characteristics optimize the stress distribution within the sheath layer, alleviating localized stress concentration caused by the interweaving of acicular wollastonite. Simultaneously, the flake talc can construct a dense physical barrier layer within the sheath layer, reducing damage to the matrix from external impacts. The acicular wollastonite is selected with an average particle size of 1000-1250 mesh, avoiding both the easy breakage of the acicular structure due to excessively large particle size and the loss of acicular morphology and weakened skeletal support due to excessively small particle size. The flake talc uses an ultrafine particle size of 4000-5000 mesh, filling the gaps between the acicular wollastonite and the microscopic defects in the PVC matrix, reducing the porosity within the sheath layer. The synergistic effect of the shape and particle size of both makes the sheath layer structure denser, reduces the generation of stress concentration points, and improves the strength of the power cable. Detailed Implementation

[0025] 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.

[0026] Unless otherwise specified, the following embodiments and comparative examples are as follows: PVC resin: Model SG-5; Needle-shaped wollastonite: aspect ratio 8~13:1, average particle size 1000 mesh; Flaky talc: average particle size is 4000 mesh; First calcium-zinc stabilizer: ash content is 15wt%~25wt%, model is HYCZ-105, manufacturer is Zanyu Technology Group Co., Ltd.; Second calcium-zinc stabilizer: ash content is 30wt%~40wt%, model is HYCZ-105XC, manufacturer is Zanyu Technology Group Co., Ltd.; Antimony trioxide: Model number FR-103.

[0027] Example 1 The sheath layer comprises the following raw materials in parts by weight: 100 parts PVC resin, 30 parts dioctyl phthalate, 20 parts filler, 4 parts stabilizer, and 5 parts additives; The filler is composed of needle-shaped wollastonite and flake-shaped talc powder in a mass ratio of 3:2, the stabilizer is the first calcium-zinc stabilizer, and the additives are composed of antioxidant 1010, ultraviolet absorber UV-531 and antimony trioxide in a mass ratio of 1:1:4. A method for manufacturing a high-strength 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 PVC resin, dioctyl phthalate and calcium zinc stabilizer for 10 minutes, then add filler and additives and mix for 15 minutes to obtain the mixture. S3. Extrude the mixture onto the semi-finished product to obtain a high-strength power cable.

[0028] Example 2 The sheath layer comprises the following raw materials in parts by weight: 100 parts PVC resin, 32 parts dioctyl phthalate, 22 parts filler, 5 parts stabilizer, and 5.5 parts additives; The filler is composed of needle-shaped wollastonite and flake-shaped talc powder in a mass ratio of 3:2, the stabilizer is the first calcium-zinc stabilizer, and the additives are composed of antioxidant 1010, ultraviolet absorber UV-531 and antimony trioxide in a mass ratio of 1:1:4. A method for manufacturing a high-strength 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 PVC resin, dioctyl phthalate and calcium zinc stabilizer for 10 minutes, then add filler and additives and mix for 15 minutes to obtain the mixture. S3. Extrude the mixture onto the semi-finished product to obtain a high-strength power cable.

[0029] Example 3 The sheath layer comprises the following raw materials in parts by weight: 100 parts PVC resin, 35 parts dioctyl phthalate, 25 parts filler, 6 parts stabilizer, and 6 parts additives; The filler consists of needle-shaped wollastonite and flake-shaped talc powder in a mass ratio of 7:4, the stabilizer is the first calcium-zinc stabilizer, and the additives consist of antioxidant 1010, ultraviolet absorber UV-531 and antimony trioxide in a mass ratio of 1:1:6. A method for manufacturing a high-strength 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 PVC resin, dioctyl phthalate and calcium zinc stabilizer for 10 minutes, then add filler and additives and mix for 15 minutes to obtain the mixture. S3. Extrude the mixture onto the semi-finished product to obtain a high-strength power cable.

[0030] Example 4 The difference between Example 4 and Example 2 is that the stabilizer is a second calcium-zinc stabilizer.

[0031] Example 5 The difference between Example 5 and Example 2 is that the stabilizer consists of a first calcium-zinc stabilizer and a second calcium-zinc stabilizer in a mass ratio of 2:1. A method for manufacturing a high-strength 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 PVC resin, dioctyl phthalate and the first calcium-zinc stabilizer for 10 minutes, then add filler, additives and the second calcium-zinc stabilizer, and mix for 15 minutes to obtain the mixture. S3. Extrude the mixture onto the semi-finished product to obtain a high-strength power cable.

[0032] Example 6 The difference between Example 6 and Example 5 is that the stabilizer consists of a first calcium-zinc stabilizer and a second calcium-zinc stabilizer in a mass ratio of 3:1.

[0033] Example 7 The difference between Example 7 and Example 6 is that Example 7 includes a method for preparing a high-strength power cable, comprising the following steps: S1. After extruding a cross-linked polyethylene insulation layer over a copper conductor, a semi-finished product is obtained; S2. Mix PVC resin, dioctyl phthalate, first calcium zinc stabilizer and second calcium zinc stabilizer for 10 minutes, then add filler and additives, and mix for 15 minutes to obtain the mixture. S3. Extrude the mixture onto the semi-finished product to obtain a high-strength power cable.

[0034] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the filler is needle-shaped wollastonite.

[0035] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the filler is flake talc powder.

[0036] Comparative Example 3 Compared with Example 2, Comparative Example 3 differs in that acicular wollastonite (with an aspect ratio of 8 to 13:1) is replaced with an equal amount of acicular wollastonite with an aspect ratio of 3 to 5:1.

[0037] Comparative Example 4 Compared with Example 2, Comparative Example 4 differs in that the acicular wollastonite (with an aspect ratio of 8 to 13:1) is replaced with an equal amount of acicular wollastonite with an aspect ratio of 15 to 20:1.

[0038] Comparative Example 5 Compared with Example 2, Comparative Example 5 differs in that the flake talc powder (average particle size of 4000 mesh) is replaced with an equal amount of flake talc powder with an average particle size of 1000 mesh.

[0039] Comparative Example 6 Compared with Example 2, Comparative Example 6 differs in that the flake talc powder (average particle size of 4000 mesh) is replaced with an equal amount of flake talc powder with an average particle size of 6000 mesh.

[0040] Experimental Example 1 The sheath of the high-strength power cables prepared in Examples 1-7 and Comparative Examples 1-6 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 Fibers - Part 11: General Test Methods for Thickness and Dimensional Measurement and Mechanical Properties". The tensile strength of the specimens was tested. The specimens were prepared by cutting the sheath along the cable axis and cutting a narrow strip to make a small dumbbell specimen with a thickness of 2.0 mm, which is the specimen to be tested.

[0041] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-7 and Comparative Examples 1-6

[0042] Table 1 shows that when both acicular wollastonite and flake talc are added as fillers to the sheath layer, with the acicular wollastonite having an aspect ratio of 8-13:1 and an average particle size of 1000-1250 mesh, and the flake talc having an average particle size of 4000-5000 mesh, the strength of the power cable can be improved. When the calcium-zinc stabilizer consists of a first calcium-zinc stabilizer and a second calcium-zinc stabilizer with different ash contents, and is added in stages, the resulting power cable exhibits even better strength.

[0043] 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 high strength power cable comprising a conductor, an insulation layer and a sheath layer arranged in this order from the inside, characterized in that, The sheath layer comprises the following raw materials in parts by weight: 100 parts PVC resin, 30-35 parts plasticizer, 20-25 parts filler, 4-6 parts stabilizer, and 5-6 parts additives; the filler is composed of acicular wollastonite and flake talc powder in a mass ratio of 6-7:4, the aspect ratio of the acicular wollastonite is 8-13:1, the average particle size of the acicular wollastonite is 1000-1250 mesh, and the average particle size of the flake talc powder is 4000-5000 mesh.

2. A high strength power cable according to claim 1, characterized in that The conductor is made of copper.

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

4. A high-strength power cable according to claim 1, characterized in that, The plasticizer includes one or more of dioctyl phthalate, diisononyl phthalate, and trioctyl trimellitate.

5. A high-strength power cable according to claim 1, characterized in that, The stabilizer includes one or both of calcium-zinc stabilizers and barium-zinc stabilizers.

6. A high-strength power cable according to claim 1, characterized in that, The additives consist of antioxidants, UV stabilizers and flame retardants in a mass ratio of 1:1:4~6.

7. A high-strength power cable according to claim 6, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076; The UV absorber includes one or more of UV absorbers UV-531, UV absorber UV-327, and UV absorber UV-326. The flame retardant includes one or more of magnesium hydroxide, aluminum hydroxide, and antimony trioxide.

8. A high-strength power cable according to claim 5, characterized in that, The calcium-zinc stabilizer is composed of a first calcium-zinc stabilizer and a second calcium-zinc stabilizer, and the first calcium-zinc stabilizer and the second calcium-zinc stabilizer have different ash contents.

9. A high-strength power cable according to claim 8, characterized in that, The ash content of the first calcium-zinc stabilizer is 15wt%~25wt%, the ash content of the second calcium-zinc stabilizer is 30wt%~40wt%, and the mass ratio of the first calcium-zinc stabilizer to the second calcium-zinc stabilizer is 2~3:

1.

10. A method for preparing a high-strength power cable, used to prepare the high-strength power cable according to any one of claims 8 to 9, characterized in that, Includes the following steps: S1. After extruding an insulating layer onto the conductor, a semi-finished product is obtained; S2. Mix the PVC resin, the plasticizer and the first calcium-zinc stabilizer for a first mixing process, then add filler, additives and the second calcium-zinc stabilizer and mix for a second mixing process to obtain a mixture. S3. The mixture is extruded onto the semi-finished product to obtain the high-strength power cable.

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