Waterproof and corrosion-resistant busbar cable and preparation method thereof

Abstract

The application relates to the technical field of cables, and discloses a waterproof and corrosion-resistant bus cable and a preparation method.The polyethylene, PET copolyester, dicumyl peroxide and the like are mixed, extruded through a screw extruder, and granulated to obtain a sheath material layer.The compatibility and interface bonding performance of the PET copolyester and the polyethylene are good, which is beneficial to improving the mechanical properties of the PET / PE composite sheath material layer and the cable, the PET copolyester and the PE are chemically crosslinked, the crosslinking degree of the molecular chains is increased, the heat resistance is improved, and the entry of corrosion media such as water and salt into the composite sheath material layer is inhibited, which is beneficial to improving the high-temperature salt water corrosion resistance of the sheath material layer and the cable, and the prepared bus cable, submarine cable and the like have better practical application in a high-salt and high-humidity environment.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a waterproof and corrosion-resistant bus cable and its preparation method. Background Technology

[0002] Cables are common devices for transmitting electrical energy and signals. In addition to meeting standard electrical performance requirements, they must also possess excellent mechanical and corrosion resistance properties. Cables typically consist of conductors, insulation layers, and sheath materials, with the sheath material playing a protective role and significantly impacting cable performance. Polyethylene sheath materials have excellent electrical insulation properties, good flexibility, and are easy to wind, making them widely used. However, traditional polyethylene sheath materials have relatively low strength and poor mechanical protection capabilities.

[0003] Polyester is a high-performance resin material with diverse varieties, good insulation properties, high mechanical strength, excellent high-temperature resistance, and easy processing. When combined with materials such as polyethylene, nylon, and polycarbonate, it can produce composite materials with even better performance. Patent CN115521525B discloses a composite material obtained by mixing polyethylene resin, vinyl-terminated hyperbranched polyester, and ethylene-vinyl acetate copolymer, which can be effectively used in wire and cable sheaths. However, this patent does not improve the tensile and other mechanical properties of the polyethylene material, which may affect the service life of the sheath material and the cable. Summary of the Invention

[0004] (a) The technical problem solved by the present invention is the poor corrosion resistance and strength of the polyethylene sheath layer and its cable.

[0005] (II) The technical solution of the present invention is: a waterproof and corrosion-resistant busbar cable and its preparation method, wherein the busbar cable includes a conductor, an insulation layer, and a sheath layer; the preparation method of the sheath layer is as follows:

[0006] S1. Add terephthalic acid, ethylene glycol, 2,2-dimethylolpropionyl oleamide, catalyst, and polymerization inhibitor to the reactor, introduce nitrogen gas, carry out esterification reaction, then carry out polycondensation reaction, discharge the material, and obtain PET copolyester.

[0007] S2. Mix polyethylene, PET copolyester and antioxidant evenly, extrude through a screw extruder, granulate, and obtain sheath material layer.

[0008] Preferably, the molar ratio of terephthalic acid, ethylene glycol, 2,2-dimethylolpropionyl oleamide, catalyst, and polymerization inhibitor in S1 is (52-60):(88-96):(4-12):(0.012-0.018):(0.003-0.01).

[0009] Preferably, the catalyst in S1 is antimony glycolate.

[0010] Preferably, the polymerization inhibitor in S1 is 2,6-di-tert-butyl-p-cresol.

[0011] Preferably, nitrogen gas is introduced into S1 to control the pressure inside the reactor to be 0.08-0.12 MPa.

[0012] Preferably, the esterification reaction in S1 is first stirred at 160-175℃ for 20-40 min, then heated to 220-240℃ and stirred until no esterified water distills out.

[0013] Preferably, the polycondensation reaction in S1 is carried out by stirring at 270-285℃ for 2-4 hours, and the pressure inside the reactor is controlled at 100-200 Pa during the reaction.

[0014] Preferably, the mass ratio of polyethylene, PET copolyester, and antioxidant in S2 is (75-90):(10-25):(0.6-1.3):(0.1-0.3).

[0015] Preferably, the temperature of each section of the screw extruder in S2 is 180-265℃, and the screw speed is 40-70 r / min.

[0016] Preferably, the preparation method of 2,2-dimethylolpropionyl oleylamine is as follows: 1,4-dioxane, 2,2-dimethylolpropionic acid, oleylamine, and N,N-dicyclohexylcarbodiimide are added to a reaction vessel to carry out an amidation reaction. After filtration, the filtrate is evaporated by rotary evaporation, and the product is recrystallized in dichloromethane to obtain 2,2-dimethylolpropionyl oleylamine.

[0017] Preferably, the molar ratio of 2,2-dimethylolpropionic acid, oleylamine, and N,N-dicyclohexylcarbodiimide is (1-1.1):1:(1-1.1).

[0018] Preferably, the amidation reaction is carried out by stirring at 20-30°C for 12-18 hours.

[0019] The beneficial technical effects of this invention are as follows: Ethylene glycol, 2,2-dimethylolpropionyl oleamide, and terephthalic acid are subjected to a melt esterification polycondensation reaction to obtain a PET copolyester. This copolyester is then blended with polyethylene, dicumyl peroxide, etc., to obtain a polyethylene sheath layer and a waterproof and corrosion-resistant busbar cable. This PET copolyester contains long alkyl chains, which improves its compatibility with polyethylene, thus enhancing the mechanical properties of the PET / PE composite sheath layer and the cable. Simultaneously, the unsaturated alkenyl groups in the PET copolyester, under the action of dicumyl peroxide, undergo a cross-linking reaction with polyethylene, strengthening the interfacial bonding performance between PET and polyethylene, and further improving the tensile strength and elongation at break of the composite sheath layer.

[0020] The PET copolyester and PE of this invention undergo chemical cross-linking, resulting in increased cross-linking degree of molecular chains, improved heat resistance, and inhibition of corrosive media such as water and salt from entering the composite sheath layer. This is beneficial for improving the high-temperature salt water corrosion resistance of the sheath layer and the cable. At the same time, the introduction of hydrophobic long carbon chains into the PET copolyester creates a steric hindrance effect, inhibiting the contact between the PET polyester molecular chains and water molecules, preventing hydrolysis of the polyester molecular chains, and giving the sheath material better corrosion resistance. It can be used to manufacture bus cables, submarine cables, etc., and has better practical applications in high-salt and high-humidity environments. Attached Figure Description

[0021] Figure 1 This is the infrared spectrum of the PET copolyester from Example 1. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] Example 1: A waterproof and corrosion-resistant bus cable, comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0024] (1) Add 2 L of 1,4-dioxane, 1.8 mol of 2,2-dimethylolpropionic acid, 1.8 mol of oleylamine, and 1.8 mol of N,N-dicyclohexylcarbodiimide to a reaction vessel. Stir the reaction at 25 °C for 18 h. After filtration, evaporate the filtrate by rotary evaporation. Recrystallize the product in dichloromethane to obtain 2,2-dimethylolpropionyloleylamine. The preparation reaction formula is:

[0025] .

[0026] (2) Add 5.7 mol terephthalic acid, 8.8 mol ethylene glycol, 1.2 mol 2,2-dimethylolpropionyl oleamide, 1.2 mmol ethylene glycol antimony, and 1 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge with nitrogen to control the pressure inside the reactor to 0.12 MPa, and heat to 165°C. Stir and react for 40 min, then heat to 220°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 200 Pa, and heat to 270°C. Stir and react for 4 h. Discharge the product to obtain PET copolyester. Figure 1 2927 cm⁻¹ in the infrared spectrum -1 and 2852cm -1 The absorption peaks are for methyl and methylene groups; 1727 cm⁻¹ -1 The absorption peak is at 1683 cm⁻¹, corresponding to the C=O group of the ester group. -1It is the absorption peak of the amide bond C=O, 1552 cm⁻¹. -1 It is the absorption peak of the benzene ring skeleton.

[0027] (3) Mix 7.5 kg of polyethylene (model Qatar Petrochemical LDPE FE3000, the same below), 2.5 kg of PET copolyester, 130 g of dicumyl peroxide and 10 g of antioxidant 1010 evenly, and extrude them through a screw extruder. The temperature of each section is 180℃, 245℃, 265℃ and 260℃, and the screw speed is 70 r / min. Granulate to obtain the sheath material layer.

[0028] Comparative Example 1: A bus cable, comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0029] (1) Add 5.7 mol terephthalic acid, 10 mol ethylene glycol, 1.2 mmol ethylene glycol antimony, and 1 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge nitrogen to control the pressure inside the reactor to 0.12 MPa and heat to 165°C. Stir and react for 40 min. Then heat to 220°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 200 Pa and heat to 270°C. Stir and react for 4 h. Discharge the product to obtain PET polyester.

[0030] (2) Mix 7.5kg polyethylene, 2.5kg PET polyester, 130g diisopropylbenzene peroxide and 10g antioxidant 1010 evenly, and extrude them through a screw extruder. The temperatures of each section are 180℃, 245℃, 265℃ and 260℃, and the screw speed is 70r / min. Granulate to obtain the sheath material layer.

[0031] Comparative Example 2: A bus cable, comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0032] (1) Add 5.7 mol terephthalic acid, 8.8 mol ethylene glycol, 1.2 mol 1,3-propanediol, 1.2 mmol ethylene glycol antimony, and 1 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge with nitrogen to control the pressure inside the reactor to 0.12 MPa, and heat to 165°C. Stir and react for 40 min, then heat to 220°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 200 Pa, and heat to 270°C. Stir and react for 4 h, then discharge to obtain PET copolyester.

[0033] (2) Mix 7.5 kg polyethylene, 2.5 kg PET copolyester, 130 g diisopropylbenzene peroxide and 10 g antioxidant 1010 evenly, and extrude them through a screw extruder. The temperatures of each section are 180℃, 245℃, 265℃ and 260℃, and the screw speed is 70 r / min. Granulate to obtain the sheath material layer.

[0034] Comparative Example 3: A bus cable comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0035] (1) Add 2 L of 1,4-dioxane, 1.8 mol of 2,2-dimethylolpropionic acid, 1.8 mol of octadecylamine, and 1.8 mol of N,N-dicyclohexylcarbodiimide to a reaction vessel. Stir the reaction at 25 °C for 18 h. After filtration, evaporate the filtrate by rotary evaporation. Recrystallize the product in dichloromethane to obtain 2,2-dimethylolpropionyloctadecylamine, with the structural formula: .

[0036] (2) Add 5.7 mol terephthalic acid, 8.8 mol ethylene glycol, 1.2 mol 2,2-dimethylolpropionyl oleamide, 1.2 mmol ethylene glycol antimony, and 1 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge nitrogen gas to control the pressure inside the reactor to 0.12 MPa, and raise the temperature to 165°C. Stir and react for 40 min, then raise the temperature to 220°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 200 Pa, raise the temperature to 270°C, stir and react for 4 h, and discharge the product to obtain PET copolyester.

[0037] (3) Mix 7.5kg polyethylene, 2.5kg PET copolyester, 130g dicumyl peroxide and 10g antioxidant 1010 evenly, and extrude them through a screw extruder. The temperatures of each section are 180℃, 245℃, 265℃ and 260℃, and the screw speed is 70r / min. Granulate to obtain the sheath material layer.

[0038] Comparative Example 4: A bus cable comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0039] (1) Add 2 L of 1,4-dioxane, 1.8 mol of 2,2-dimethylolpropionic acid, 1.8 mol of 2-methylallylamine, and 1.8 mol of N,N-dicyclohexylcarbodiimide to a reaction vessel. Stir the reaction at 25 °C for 18 h. After filtration, distill the filtrate under reduced pressure to remove low-boiling substances, yielding 2,2-dimethylolpropionyl (methylallyl)amine with the following structural formula: .

[0040] (2) Add 5.7 mol terephthalic acid, 8.8 mol ethylene glycol, 1.2 mol 2,2-dimethylolpropionylamine, 1.2 mmol ethylene glycol antimony, and 1 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge nitrogen gas to control the pressure inside the reactor to 0.12 MPa, and raise the temperature to 165°C. Stir and react for 40 min, then raise the temperature to 220°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 200 Pa, raise the temperature to 270°C, stir and react for 4 h, and discharge the product to obtain PET copolyester.

[0041] (3) Mix 7.5kg polyethylene, 2.5kg PET copolyester, 130g dicumyl peroxide and 10g antioxidant 1010 evenly, and extrude them through a screw extruder. The temperatures of each section are 180℃, 245℃, 265℃ and 260℃, and the screw speed is 70r / min. Granulate to obtain the sheath material layer.

[0042] Example 2: A waterproof and corrosion-resistant bus cable, comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0043] (1) Add 1.2 L of 1,4-dioxane, 1.1 mol of 2,2-dihydroxymethylpropionic acid, 1 mol of oleylamine, and 1.1 mol of N,N-dicyclohexylcarbodiimide to the reaction vessel, stir and react at 20 °C for 18 h, filter, evaporate the filtrate by rotary evaporation, and recrystallize the product in dichloromethane to obtain 2,2-dihydroxymethylpropionyl oleylamine.

[0044] (2) Add 5.2 mol terephthalic acid, 9.2 mol ethylene glycol, 0.8 mol 2,2-dimethylolpropionyl oleamide, 1.8 mmol ethylene glycol antimony, and 0.6 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge with nitrogen to control the pressure inside the reactor to 0.08 MPa, and heat to 160°C. Stir and react for 40 min, then heat to 240°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 100 Pa, and heat to 280°C. Stir and react for 3 h, then discharge to obtain PET copolyester.

[0045] (3) Mix 8.5 kg polyethylene, 1.5 kg PET copolyester, 100 g diisopropylbenzene peroxide and 23 g antioxidant 1010 evenly, and extrude them through a screw extruder. The temperatures of each section are 180℃, 245℃, 265℃ and 260℃, and the screw speed is 70 r / min. Granulate to obtain the sheath material layer.

[0046] Example 3: A waterproof and corrosion-resistant bus cable, comprising an aluminum conductor, a cross-linked polyethylene insulation layer, and a polyethylene sheath layer; the method for preparing the sheath layer is as follows:

[0047] (1) Add 600 mL of 1,4-dioxane, 0.55 mol of 2,2-dihydroxymethylpropionic acid, 0.5 mol of oleylamine and 0.55 mol of N,N-dicyclohexylcarbodiimide to the reaction vessel, stir and react at 30 °C for 12 h, filter, evaporate the filtrate by rotary evaporation, and recrystallize the product in dichloromethane to obtain 2,2-dihydroxymethylpropionyl oleylamine.

[0048] (2) Add 6 mol terephthalic acid, 9.6 mol ethylene glycol, 0.4 mol 2,2-dimethylolpropionyl oleamide, 1.6 mmol ethylene glycol antimony, and 0.3 mmol 2,6-di-tert-butyl-p-cresol to the reactor. Purge with nitrogen to control the pressure inside the reactor to 0.12 MPa, and heat to 175°C. Stir and react for 20 min, then heat to 230°C and stir until no esterified water distills out. Vacuum the reactor to control the pressure inside to 200 Pa, and heat to 285°C. Stir and react for 2 h, then discharge to obtain PET copolyester.

[0049] (3) Mix 9kg polyethylene, 1kg PET copolyester, 60g dicumyl peroxide and 30g antioxidant 1010 evenly, and extrude them through a screw extruder. The temperatures of each section are 180℃, 245℃, 265℃ and 260℃, and the screw speed is 40r / min. Granulate to obtain the sheath material layer.

[0050] The sheath material granules were injection molded into strips, and the tensile properties were tested according to standard GB / T 1040.1-2025.

[0051] The sheathing material granules are pressed into thin sheets with a thickness of about 2 mm, dried to a constant weight m0, placed in a 3.5% sodium chloride aqueous solution, heated to 90℃, and kept at that temperature for 240 h. During the holding period, water is continuously added until a constant volume is reached. The sheathing material granules are then removed, dried to a constant weight m, and the mass retention rate W is calculated. W = (m0 - m) / m0 × 100%. The higher the mass retention rate, the better the corrosion resistance.

[0052] The specific performance test results are shown in Table 1.

[0053] Table 1 Performance Tests

[0054]

[0055] Compared to Comparative Example 1, the PET copolyester in Example 1 contains long alkyl chains, which improves its compatibility with polyethylene and enhances the mechanical properties of the PET / PE composite sheath layer. It also contains unsaturated alkenyl groups in the PET copolyester, which, under the action of dicumyl peroxide, undergo a cross-linking reaction with polyethylene, strengthening the interfacial bonding between PET and polyethylene and further improving the mechanical properties of the composite sheath layer. This results in higher tensile strength and elongation at break. After chemical cross-linking, the degree of cross-linking of the PET and PE molecular chains increases, improving heat resistance and inhibiting the entry of corrosive media such as water and salt into the composite sheath layer, thus improving its resistance to high-temperature salt water corrosion. Simultaneously, the introduction of hydrophobic long carbon chains in the PET copolyester creates a steric hindrance effect, inhibiting contact between the PET polyester molecular chains and water molecules, preventing hydrolysis of the polyester molecular chains, and improving the quality retention rate of the sheath layer against salt water corrosion. Examples 2 and 3, by adjusting the ratio of polyethylene and PET copolyester, also exhibit excellent mechanical properties and water and corrosion resistance.

[0056] Compared with Example 1, the PET copolyester of Comparative Example 2 does not contain alkenyl groups and long carbon chains, has poor compatibility with polyethylene, and cannot undergo cross-linking reaction with polyethylene. The tensile strength and elongation at break of the sheath layer are low, and the PET copolyester molecular chain is easy to hydrolyze, resulting in poor water and corrosion resistance.

[0057] The PET copolyester of Comparative Example 3 does not contain long carbon chains, and the PET copolyester of Comparative Example 4 does not contain alkenyl groups. The tensile strength and elongation at break of the sheath layer of both are lower than those of Example 1, and the quality retention rate of hydrochloric acid corrosion is low.

[0058] Although the invention has been described herein with reference to illustrative embodiments thereof, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein.

Claims

1. A method for preparing a waterproof and corrosion-resistant busbar cable, the busbar cable comprising a conductor, an insulation layer, and a sheath layer; characterized in that, The method for preparing the sheath material layer includes: S1. Add terephthalic acid, ethylene glycol, 2,2-dimethylolpropionyl oleamide, catalyst, and polymerization inhibitor to the reactor, introduce nitrogen gas, carry out esterification reaction, then carry out polycondensation reaction, discharge the material, and obtain PET copolyester. S2. Mix polyethylene, PET copolyester, dicumyl peroxide and antioxidant, extrude through a screw extruder, granulate, and obtain the sheath material layer; The preparation method of 2,2-dihydroxymethylpropionyl oleylamine is as follows: 1,4-dioxane, 2,2-dihydroxymethylpropionic acid, oleylamine, and N,N-dicyclohexylcarbodiimide in a molar ratio of (1-1.1):1:(1-1.1) are added to a reaction vessel, and the mixture is stirred and reacted at 20-30℃ for 12-18h. After filtration, the filtrate is evaporated by rotary evaporation, and the product is recrystallized to obtain 2,2-dihydroxymethylpropionyl oleylamine.

2. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, The molar ratio of terephthalic acid, ethylene glycol, 2,2-dimethylolpropionyl oleamide, catalyst, and polymerization inhibitor in S1 is (52-60):(88-96):(4-12):(0.012-0.018):(0.003-0.01).

3. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, The catalyst in S1 is antimony glycolate, and the polymerization inhibitor is 2,6-di-tert-butyl-p-cresol.

4. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, Nitrogen gas is introduced into S1 to control the pressure inside the reactor to 0.08-0.12 MPa.

5. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, The esterification reaction in S1 is first carried out at 160-175℃ for 20-40 minutes, and then the temperature is raised to 220-240℃ until no esterified water is distilled off.

6. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, The polycondensation reaction in S1 is carried out at 270-285℃ for 2-4 hours, and the pressure inside the reactor is controlled at 100-200Pa.

7. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, The mass ratio of polyethylene, PET copolyester, and antioxidant in S2 is (75-90):(10-25):(0.6-1.3):(0.1-0.3).

8. The method for preparing the waterproof and corrosion-resistant busbar cable according to claim 1, characterized in that, The temperature of each section of the screw extruder in S2 is 180-265℃, and the screw speed is 40-70 r / min.

9. A waterproof and corrosion-resistant bus cable obtained by the preparation method according to any one of claims 1-8.

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