Corrosion-resistant low-voltage power cable and preparation method thereof

Abstract

The invention relates to the technical field of power cables, and provides a corrosion-resistant low-voltage power cable and a preparation method thereof. A corrosion-resistant low-voltage power cable 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 polyvinyl chloride, 8-10 parts of chlorinated polyethylene, 20-25 parts of plasticizer, 3-5 parts of stabilizer, 15-20 parts of filler, 1-1.5 parts of antioxidant and 1-1.5 parts of lubricant. The plasticizer is prepared from an aromatic carboxylic ester compound, triphenyl phosphate and polypropylene glycol adipate according to the mass ratio of (4 to 5) to 1 to 3. According to the technical scheme, the problem of insufficient corrosion resistance 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, specifically to a corrosion-resistant low-voltage power cable and its manufacturing method. Background Technology

[0002] Low-voltage power cables are widely used in complex environments such as municipal engineering, chemical industrial parks, mines, farmland irrigation, and underground installations. This results in long-term contact between the cables and acidic or alkaline soil media, groundwater, corrosive industrial waste liquids, humid and moldy environments, and various chemical pollutants. Therefore, corrosion resistance is a core indicator determining the cable's service life and operational safety.

[0003] The mainstream material for the sheath of low-voltage power cables is polyvinyl chloride (PVC). PVC has advantages such as low cost, good processability, and excellent insulation performance, making it the preferred base material for low-voltage cable sheaths. However, pure PVC lacks toughness and is difficult to process and mold, so plasticizers must be added to improve its plasticizing and processing performance and flexibility to meet the molding and mechanical requirements of the cable sheath. However, the addition of plasticizers is a double-edged sword. The addition of plasticizers directly destroys the original dense molecular structure of PVC, forming channels for corrosive media to penetrate. Furthermore, the ester groups in some plasticizers are easily hydrolyzed, saponified, and extracted by acid, alkali, and oil corrosive media, causing the PVC sheath layer to rapidly deteriorate and fail in complex corrosive environments, thus failing to meet the corrosion resistance requirements of low-voltage power cables for long-term service.

[0004] If the cable's corrosion resistance is insufficient, the sheath layer is easily corroded, swollen, aged, and embrittled by corrosive media. In mild cases, this can lead to sheath cracking, powdering, and detachment, resulting in decreased cable insulation performance and causing faults such as leakage and short circuits, affecting stable power transmission. In severe cases, it can cause oxidation and corrosion of the cable conductor, completely losing its power transmission function. This not only increases the cost of cable maintenance and replacement but also easily leads to safety accidents such as electric shock and fire, posing serious safety hazards to industrial production and residential electricity use.

[0005] Therefore, it is very necessary to develop a corrosion-resistant low-voltage power cable. Summary of the Invention

[0006] This invention proposes a corrosion-resistant low-voltage power cable and its preparation method, which solves the problem of insufficient corrosion resistance of low-voltage power cables in related technologies.

[0007] The technical solution of the present invention is as follows: The present invention proposes a corrosion-resistant low-voltage power cable, comprising a conductor, an insulation layer and a sheath layer arranged sequentially from the inside to the outside. The sheath layer comprises the following raw materials in parts by weight: 100 parts of polyvinyl chloride, 8-10 parts of chlorinated polyethylene, 20-25 parts of plasticizer, 3-5 parts of stabilizer, 15-20 parts of filler, 1-1.5 parts of antioxidant, and 1-1.5 parts of lubricant. The plasticizer is composed of aromatic carboxylic acid ester compounds, triphenyl phosphate and polypropylene adipate in a mass ratio of 4-5:1:3.

[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 aromatic carboxylic acid ester compound is composed of an aromatic tricarboxylic acid ester compound and an aromatic dicarboxylic acid ester compound in a mass ratio of 6~7:3.

[0011] In the sheath layer of the corrosion-resistant low-voltage power cable of this invention, the aromatic carboxylic acid ester compounds are composed of aromatic tricarboxylic acid ester compounds and aromatic dicarboxylic acid ester compounds. The aromatic tricarboxylic acid ester compounds contain three ester groups, forming a multi-point three-dimensional ester group protective structure based on the aromatic rings. The ester groups have high steric hindrance, resulting in strong resistance to migration and precipitation, preventing the ester groups from being extracted and lost by the corrosive medium. However, their plasticizing effect is insufficient, and uneven plasticization will lead to a decrease in matrix density, which is detrimental to improving corrosion resistance. The aromatic dicarboxylic acid ester compounds have weaker resistance to migration and precipitation, but superior plasticizing effect. The synergy of both helps to form a denser plasticized matrix, improving the corrosion resistance of the low-voltage power cable.

[0012] As a further technical solution, the aromatic tricarboxylic acid ester compound is trioctyl trimellitate, and the number of carbon atoms in a single carboxylic acid moiety of the aromatic dicarboxylic acid ester compound is 8 to 10.

[0013] In the sheath layer of the corrosion-resistant low-voltage power cable of this invention, the number of carbon atoms in a single carboxylic acid moiety of the aromatic dicarboxylic acid ester compound is 8 to 10. If the carbon chain length is less than 8, the plasticizer will migrate and have a high rate of volatilization loss. If the carbon chain length is greater than 10, it will increase the steric hindrance of the molecules, making it difficult to quickly insert into the molecular chain gaps of polyvinyl chloride, thus weakening the plasticizing ability. When the number of carbon atoms in a single carboxylic acid moiety of the aromatic dicarboxylic acid ester compound is 8 to 10, it can achieve both good plasticizing effect and a certain degree of migration resistance, which helps to improve the corrosion resistance of the low-voltage power cable.

[0014] As a further technical solution, the aromatic dicarboxylic acid ester compound includes one or more of dioctyl phthalate, diisononyl phthalate, and diisodecyl phthalate.

[0015] As a further technical solution, the stabilizer includes one or two of calcium-zinc composite stabilizer and tribasic lead sulfate, preferably calcium-zinc composite stabilizer.

[0016] This invention adds a stabilizer to the sheath layer of a corrosion-resistant low-voltage power cable. During the extrusion process and cable service, high temperatures can easily cause the molecular chains of polyvinyl chloride (PVC) to degrade due to the removal of HCl, producing unsaturated double bonds and forming a conjugated structure, which leads to yellowing, embrittlement, and cracking of the sheath layer. The stabilizer can capture the HCl produced by degradation, block the chain reaction of HCl removal, inhibit the high-temperature decomposition of PVC, ensure the smooth extrusion molding of the sheath layer, and prevent processing defects such as scorching, yellowing, and carbonization, thus ensuring a stable and controllable processing process.

[0017] As a further technical solution, the filler includes one or more of talc, calcium carbonate, and carbon black, preferably calcium carbonate.

[0018] As a further technical solution, the antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1 to 1.2:1, preferably antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0019] The present invention adds an antioxidant to the sheath layer of the corrosion-resistant low-voltage power cable. The antioxidant can capture free radicals, decompose peroxides, terminate the chain reaction of oxidation aging, avoid the sheath layer from becoming embrittled, powdery, and cracked due to oxidation, maintain the integrity of the molecular chain structure, delay the aging and deterioration of the sheath layer, and extend the service life of the cable.

[0020] As a further technical solution, the lubricant includes one or both of stearic acid and zinc stearate, preferably zinc stearate.

[0021] This invention adds a lubricant to the sheath layer of a corrosion-resistant low-voltage power cable. The lubricant allows for more uniform mixing of the sheath layer components and more thorough plasticization, preventing the formation of internal micropores, bubbles, and stress concentration points due to uneven local plasticization. This ensures a dense and intact internal structure of the sheath layer. At the same time, the addition of lubricant enables dual lubrication, reducing the viscosity of the PVC melt, improving processing fluidity, preventing sticking to the mold and machine, ensuring a smooth sheath surface, and improving product quality.

[0022] This invention also proposes a method for preparing a corrosion-resistant 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 raw materials of the sheath layer evenly and extrude them onto the semi-finished product to obtain the corrosion-resistant low-voltage power cable.

[0023] The working principle and beneficial effects of this invention are as follows: This invention relates to a corrosion-resistant low-voltage power cable whose sheath layer uses polyvinyl chloride (PVC) as the raw material and adds a plasticizer composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate to improve the corrosion resistance of the low-voltage power cable. In existing technologies, plasticizers are often added to improve the processing performance of PVC; however, the ester groups in some plasticizers are easily hydrolyzed, saponified, and extracted by acidic, alkaline, and oily corrosive media, reducing the corrosion resistance of the PVC sheath layer. In this invention, the plasticizer is composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate. The aromatic carboxylic acid esters form a protective structure based on the rigid skeleton of aromatic rings, making the ester groups less susceptible to attack by corrosive media. Triphenyl phosphate has a phosphorus oxyester structure, with chemical stability far superior to conventional carboxylic acid esters. It exhibits outstanding resistance to hydrolysis, saponification, and oil extraction, and can also form an oleophobic protective film on the sheath layer surface, enhancing oil and solvent corrosion resistance. Polypropylene adipate (PPA) is a high-molecular-weight polyester plasticizer. Its ester groups are linked in series within an ultra-long molecular chain, eliminating free attack sites. It exhibits strong resistance to hydrolysis and migration, preventing the formation of micropores due to plasticizer loss and thus blocking the formation of penetration channels for corrosive media. The synergistic effect of these three components not only addresses the issues of easy corrosion and migration of conventional ester groups by optimizing the ester group structure, but also effectively blocks corrosion penetration paths for different types of corrosive media, improving the corrosion resistance of low-voltage power cables. Detailed Implementation

[0024] 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.

[0025] In the following examples and comparative examples: Polyvinyl chloride: Model S-70; Chlorinated polyethylene: Model number CPE-135A; Calcium carbonate: average particle size is 400 mesh; Polypropylene adipate: Model number UN615.

[0026] Example 1 The sheath layer comprises the following raw materials in parts by weight: 100 parts polyvinyl chloride, 8 parts chlorinated polyethylene, 20 parts plasticizer, 3 parts calcium-zinc composite stabilizer, 15 parts calcium carbonate, 1 part antioxidant, and 1 part zinc stearate. The plasticizer is composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate in a mass ratio of 4:1:3; the antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1; and the aromatic carboxylic acid ester is trioctyl trimellitate. A method for preparing a corrosion-resistant 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 of the sheath layer evenly and extrude them onto the outside of the semi-finished product to obtain a corrosion-resistant low-voltage power cable.

[0027] Example 2 The sheath layer comprises the following raw materials in parts by weight: 100 parts polyvinyl chloride, 9 parts chlorinated polyethylene, 22 parts plasticizer, 4 parts calcium-zinc composite stabilizer, 18 parts calcium carbonate, 1.2 parts antioxidant, and 1.2 parts zinc stearate; The plasticizer is composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate in a mass ratio of 4:1:3; the antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1; and the aromatic carboxylic acid ester is trioctyl trimellitate. A method for preparing a corrosion-resistant 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 of the sheath layer evenly and extrude them onto the outside of the semi-finished product to obtain a corrosion-resistant low-voltage power cable.

[0028] Example 3 The sheath layer comprises the following raw materials in parts by weight: 100 parts polyvinyl chloride, 10 parts chlorinated polyethylene, 25 parts plasticizer, 5 parts calcium-zinc composite stabilizer, 20 parts calcium carbonate, 1.5 parts antioxidant, and 1.5 parts zinc stearate. The plasticizer is composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate in a mass ratio of 5:1:3; the antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1; and the aromatic carboxylic acid ester is trioctyl trimellitate. A method for preparing a corrosion-resistant 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 of the sheath layer evenly and extrude them onto the outside of the semi-finished product to obtain a corrosion-resistant low-voltage power cable.

[0029] Example 4 The difference between Example 4 and Example 2 is that the aromatic carboxylic acid ester compound is dioctyl phthalate.

[0030] Example 5 The difference between Example 5 and Example 2 is that the aromatic carboxylic acid ester compound is composed of trioctyl trimellitate and dioctyl phthalate in a mass ratio of 2:1.

[0031] Example 6 The difference between Example 6 and Example 2 is that the aromatic carboxylic acid ester compound is composed of trioctyl trimellitate and dioctyl phthalate in a mass ratio of 7:3.

[0032] Example 7 The difference between Example 7 and Example 6 is that the aromatic carboxylic acid ester compound is composed of trioctyl trimellitate and diisononyl phthalate in a mass ratio of 7:3.

[0033] Example 8 The difference between Example 8 and Example 6 is that the aromatic carboxylic acid ester compound is composed of trioctyl trimellitate and diisodecyl phthalate in a mass ratio of 7:3.

[0034] Example 9 The difference between Example 9 and Example 6 is that the aromatic carboxylic acid ester compound is composed of trioctyl trimellitate and diisobutyl phthalate in a mass ratio of 7:3.

[0035] Example 10 The difference between Example 10 and Example 6 is that the aromatic carboxylic acid ester compound is composed of trioctyl trimellitate and diisodecyl phthalate in a mass ratio of 7:3.

[0036] Comparative Example 1 Compared with Example 2, Comparative Example 1 differs in that the plasticizer is composed of trioctyl trimellitate and polypropylene adipate in a mass ratio of 4:3.

[0037] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the plasticizer is trioctyl trimellitate.

[0038] Experimental Example 1 The sheaths of the corrosion-resistant low-voltage power cables prepared in Examples 1-10 and Comparative Examples 1-2 were immersed in a 30% hydrochloric acid solution for 72 hours. The tensile strength of the samples before and after immersion was tested according to the test method specified in GB / T 1040.2-2022. The test speed was 200 mm / min and the sample type was 1A.

[0039] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-10 and Comparative Examples 1-2

[0040] Table 1 shows that when the plasticizer is composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate, it can improve the corrosion resistance of low-voltage power cables. When the aromatic carboxylic acid esters consist of aromatic tricarboxylic acid esters and aromatic dicarboxylic acid esters, and the number of carbon atoms in a single carboxylic acid moiety in the aromatic dicarboxylic acid ester is 8-10, the resulting low-voltage power cable exhibits even better corrosion resistance.

[0041] 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 corrosion-resistant 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 polyvinyl chloride, 8-10 parts chlorinated polyethylene, 20-25 parts plasticizer, 3-5 parts stabilizer, 15-20 parts filler, 1-1.5 parts antioxidant, and 1-1.5 parts lubricant. The plasticizer is composed of aromatic carboxylic acid esters, triphenyl phosphate, and polypropylene adipate in a mass ratio of 4-5:1:

3.

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

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

4. The corrosion-resistant low-voltage power cable according to claim 1, characterized in that, The aromatic carboxylic acid ester compounds are composed of aromatic tricarboxylic acid ester compounds and aromatic dicarboxylic acid ester compounds in a mass ratio of 6 to 7:

3.

5. The corrosion-resistant low-voltage power cable according to claim 4, characterized in that, The aromatic tricarboxylic acid ester compound is trioctyl trimellitate, and the aromatic dicarboxylic acid ester compound has 8 to 10 carbon atoms in a single carboxylic acid moiety.

6. A corrosion-resistant low-voltage power cable according to claim 5, characterized in that, The aromatic dicarboxylic acid ester compounds include one or more of dioctyl phthalate, diisononyl phthalate, and diisodecyl phthalate.

7. The corrosion-resistant low-voltage power cable according to claim 1, characterized in that, The stabilizer includes one or two of calcium-zinc composite stabilizers and tribasic lead sulfate.

8. The corrosion-resistant low-voltage power cable according to claim 1, characterized in that, The filler includes one or more of talc, calcium carbonate, and carbon black.

9. A corrosion-resistant low-voltage power cable according to claim 1, characterized in that, The antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1~1.2:1; The lubricant includes one or both of stearic acid and zinc stearate.

10. A method for preparing a corrosion-resistant low-voltage power cable, used to prepare the corrosion-resistant low-voltage power cable according to any one of claims 1 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 raw materials of the sheath layer evenly and extrude them onto the semi-finished product to obtain the corrosion-resistant low-voltage power cable.

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