Low temperature resistant low voltage power cable

Abstract

The application relates to the technical field of cables, and discloses a low-temperature-resistant low-voltage power cable which comprises, from inside to outside, an insulating wire core, a shielding layer and a sheath layer; the insulating wire core is composed of a conductor and an insulating layer wrapped outside the conductor; the insulating layer is a cross-linked polyethylene insulating layer; the sheath layer comprises the following components in parts by weight: 100 parts of polyvinyl chloride, 5-13 parts of ethylene-propylene-diene rubber, 4-8 parts of polyurethane elastomer, 15-25 parts of fillers, 4-6 parts of stabilizers, 10-15 parts of cold-resistant additives, 6-10 parts of plasticizers and 15-21 parts of flame retardants; the cold-resistant additives comprise ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol in a weight ratio of 1-9:1; the technical scheme can solve the problem of poor low-temperature resistance of the sheath layer of the power cable in the related art.

Description

Technical Field

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

[0002] Power cables, as a crucial component of electrical energy transmission, are widely used in industries, construction, transportation, and urban infrastructure. With the rapid development of my country's power industry, the performance requirements for power cables are constantly increasing, especially in low-temperature environments, where cable performance directly impacts the safe and stable operation of the power system.

[0003] In low-temperature environments, the sheathing materials of traditional power cables are prone to hardening and brittleness, leading to a decline in the cable's protective performance and even causing safety hazards such as short circuits and leakage. Currently, although the commonly used polyvinyl chloride (PVC) sheathing material has good insulation properties and processability, its low-temperature toughness is poor, making it difficult to meet the usage requirements in cold regions or low-temperature operating conditions.

[0004] To improve the low-temperature resistance of cable sheaths, existing technologies often involve adding plasticizers to enhance the material's flexibility. However, conventional plasticizers tend to migrate or precipitate at low temperatures, limiting the improvement in the low-temperature resistance of cable sheaths.

[0005] Therefore, a low-temperature resistant power cable is proposed, which has good low-temperature resistance, and this is of great significance for extending the service life of power cables in low-temperature environments. Summary of the Invention

[0006] This invention proposes a low-temperature resistant low-voltage power cable, which solves the problem of poor low-temperature resistance of the sheath layer of power cables in related technologies.

[0007] The technical solution of the present invention is as follows: This invention proposes a low-temperature resistant, low-voltage power cable, comprising, from the inside out, an insulated core, a shielding layer, and a sheathing layer. The insulated core consists of a conductor and an insulating layer covering the conductor; the insulating layer is a cross-linked polyethylene insulating layer; the sheathing layer comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5-13 parts ethylene propylene diene monomer (EPDM) rubber, 4-8 parts polyurethane elastomer, 20-25 parts filler, 4-6 parts stabilizer, 10-15 parts cold-resistant additive, 6-10 parts plasticizer, and 15-21 parts flame retardant; The cold-resistant additives include ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol in a weight ratio of 1 to 9:1.

[0008] As a further technical solution, the weight ratio of the ethylene-butyl acrylate-carbonyl terpolymer and the phthalic anhydride polyester polyol is 2~5:1.

[0009] As a further technical solution, the number average molecular weight of the phthalic anhydride polyester polyol is 1000~2500, for example, 1000, 2000, 2500, preferably 2000.

[0010] As a further technical solution, the filler includes one or more of the following: calcium carbonate, silica, barium sulfate, kaolin, talc, mica powder, pyrophyllite powder, and attapulgite.

[0011] As a further technical solution, when the filler is pyrophyllite powder, the pyrophyllite powder is modified pyrophyllite powder; The raw materials for the modified pyrophyllite powder include pyrophyllite powder, titanate coupling agent, and vinyl chloride-vinyl acetate copolymer.

[0012] As a further technical solution, in the raw materials of the modified pyrophyllite powder, the weight ratio of the titanate coupling agent and the vinyl chloride-vinyl acetate copolymer to the pyrophyllite powder is 3~7:30, for example, it can be 3:30, 4:30, 5:30, 6:30, 7:30, preferably 5:30.

[0013] As a further technical solution, the weight ratio of the titanate coupling agent and the vinyl chloride-vinyl acetate copolymer is 1:4.

[0014] In this invention, by using titanate coupling agent and vinyl chloride-vinyl acetate copolymer to modify pyrophyllite powder, the pyrophyllite powder can be better dispersed in the organic matrix of the sheath layer, thereby improving the stability of the power cable sheath layer and giving it good mechanical strength.

[0015] In this invention, by optimizing the ratio of titanate coupling agent, vinyl chloride-vinyl acetate copolymer, and pyrophyllite powder, the mechanical strength of the power cable sheath can be further improved when the weight ratio of titanate coupling agent and vinyl chloride-vinyl acetate copolymer to pyrophyllite powder is 5:30.

[0016] As a further technical solution, the titanate coupling agent includes one or two of monoalkoxy titanates and pyrophosphate-type monoalkoxy titanates, preferably pyrophosphate-type monoalkoxy titanates.

[0017] In this invention, the titanate coupling agent can be any titanate coupling agent in the art, such as isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl triisostearoyl titanate, preferably isopropyl tris(dioctyl pyrophosphate) titanate.

[0018] As a further technical solution, the preparation method of the modified pyrophyllite powder includes the following steps: A1. After preparing the titanate coupling agent into a solution, add pyrophyllite powder and dry to obtain pretreated pyrophyllite powder. A2. The pretreated pyrophyllite powder and vinyl chloride-vinyl acetate copolymer are blended, melted, dried, and pulverized to obtain modified pyrophyllite powder.

[0019] As a further technical solution, the average particle size of the modified pyrophyllite powder is 10~50μm.

[0020] As a further technical solution, the conductor is made of either aluminum alloy or copper alloy; The shielding layer is a copper wire braided shielding layer.

[0021] As a further technical solution, the sheath layer also includes 1-3 parts of antioxidant and 4-6 parts of compatibilizer.

[0022] As a further technical solution, the stabilizer includes a calcium-zinc stabilizer.

[0023] As a further technical solution, the plasticizer includes one or two of dioctyl phthalate and dioctyl sebacate, preferably dioctyl sebacate.

[0024] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 1098, and antioxidant 168.

[0025] As a further technical solution, the flame retardant includes a hydroxide flame retardant and a phosphorus-based flame retardant in a weight ratio of 2:1.

[0026] In this invention, the hydroxide flame retardant is any hydroxide flame retardant in the art, such as magnesium hydroxide or aluminum hydroxide, preferably aluminum hydroxide; the phosphorus flame retardant is any phosphorus flame retardant in the art, such as tricresyl phosphate, melamine polyphosphate, or diethyl aluminum hypophosphite, preferably tricresyl phosphate.

[0027] As a further technical solution, the compatibilizer includes maleic anhydride-grafted EPDM rubber.

[0028] This invention proposes a method for preparing a low-temperature resistant low-voltage power cable, comprising the following steps: An insulating layer is wrapped around the conductor to obtain an insulated core; after a shielding layer is set on the surface of the insulated core, the components of the sheath layer are blended and extruded to cover the outer periphery of the shielding layer to obtain a low-temperature and low-voltage power cable.

[0029] The working principle and beneficial effects of this invention are as follows: The sheath layer of the low-temperature resistant low-voltage power cable of this invention uses polyvinyl chloride (PVC) as the main base material, combined with ethylene propylene diene monomer (EPDM) rubber, polyurethane elastomer, fillers, stabilizers, cold-resistant additives, plasticizers, and flame retardants. Through the rational combination of these components, a power cable sheath layer with good stability and excellent low-temperature resistance can be prepared. Specifically, cold-resistant additives such as ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol are added. The ethylene-n-butyl acrylate-carbonyl terpolymer exhibits good flexibility and low-temperature adaptability. The n-butyl acrylate side chains in its molecular structure increase the distance between molecular chains, reduce the intermolecular forces, and make the molecular chains more mobile at low temperatures. The phthalic anhydride polyester polyol can fill the spaces between the PVC molecular chains, further reducing the intermolecular forces and improving the mobility of the molecular chains. By using a combination of ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol, the problem of conventional plasticizers easily precipitating at low temperatures can be avoided, ensuring that the sheath layer of power cables still has good flexibility in low-temperature environments. By using a combination of ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol and reasonably controlling the weight ratio of the two to 1~9:1, the low-temperature resistance of power cables can be significantly improved. Detailed Implementation

[0030] 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.

[0031] In the following examples and comparative examples, the polyvinyl chloride (PVC) is model S-1000; the ethylene propylene diene monomer (EPDMS505A) is model EPDMS505A; the polyurethane elastomer is model TPU 1195A; the ethylene-butyl acrylate-carbonyl terpolymer is model HP441; the phthalic anhydride polyester polyol has a number average molecular weight of 2000 and is model HKP-456; and the maleic anhydride-grafted ethylene propylene diene monomer (EPD) is grade K-7M with a density of 0.87 g / cm³. 3 The melt flow index is 0.6 g / 10 min; the average particle size of talc, pyrophyllite, and mica is 45 μm; the calcium-zinc stabilizer is a calcium-zinc composite stabilizer, model BPR618R; polypropylene adipate has a number average molecular weight of 2000 and an effective ingredient content of 98%; ethylene-vinyl acetate copolymer, model EVA 18J3; and the average particle size of modified pyrophyllite powder is 45 μm.

[0032] Example 1 A method for preparing a low-temperature resistant, low-voltage power cable includes the following steps: S1. After coating the aluminum alloy conductor with a cross-linked polyethylene insulation layer, an insulated wire core is obtained; S2. After wrapping a copper wire braided shielding layer around the surface of the insulated core, 100 parts of polyvinyl chloride, 5 parts of ethylene propylene diene monomer (EPDM) rubber, 4 parts of polyurethane elastomer, 5 parts of ethylene-butyl acrylate-carbonyl terpolymer, 5 parts of phthalic anhydride polyester polyol, and 4 parts of maleic anhydride-grafted EPDM rubber are blended together, and then 15 parts of talc, 4 parts of calcium-zinc stabilizer, 6 parts of dioctyl sebacate, 10 parts of aluminum hydroxide, 5 parts of tricresyl phosphate, and 1 part of antioxidant 1010 are added and extruded to coat the outer surface of the copper wire braided shielding layer to obtain a low-temperature and low-voltage power cable.

[0033] Example 2 A method for preparing a low-temperature resistant, low-voltage power cable includes the following steps: S1. After coating the aluminum alloy conductor with a cross-linked polyethylene insulation layer, an insulated wire core is obtained; S2. After wrapping a copper wire braided shielding layer around the surface of the insulated core, 100 parts of polyvinyl chloride, 10 parts of ethylene propylene diene monomer (EPDM) rubber, 6 parts of polyurethane elastomer, 7.5 parts of ethylene-n-butyl acrylate-carbonyl terpolymer, 7.5 parts of phthalic anhydride polyester polyol, and 5 parts of maleic anhydride-grafted EPDM rubber are blended, and then 20 parts of pyrophyllite powder, 5 parts of calcium-zinc stabilizer, 8 parts of dioctyl sebacate, 12 parts of aluminum hydroxide, 6 parts of tricresyl phosphate, and 2 parts of antioxidant 1010 are added and extruded to coat the outer surface of the copper wire braided shielding layer to obtain a low-temperature and low-voltage power cable.

[0034] Example 3 A method for preparing a low-temperature resistant, low-voltage power cable includes the following steps: S1. After coating the aluminum alloy conductor with a cross-linked polyethylene insulation layer, an insulated wire core is obtained; S2. After wrapping a copper wire braided shielding layer around the surface of the insulated core, 100 parts of polyvinyl chloride, 13 parts of ethylene propylene diene monomer (EPDM) rubber, 8 parts of polyurethane elastomer, 13.5 parts of ethylene-n-butyl acrylate-carbonyl terpolymer, 1.5 parts of phthalic anhydride polyester polyol, and 6 parts of maleic anhydride-grafted EPDM rubber are blended, and then 25 parts of mica powder, 6 parts of calcium-zinc stabilizer, 10 parts of dioctyl sebacate, 14 parts of aluminum hydroxide, 7 parts of tricresyl phosphate, and 3 parts of antioxidant 1010 are added and extruded to coat the outer periphery of the copper wire braided shielding layer to obtain a low-temperature and low-voltage power cable.

[0035] Example 4 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the amount of ethylene-butyl acrylate-carbonyl terpolymer added is 13.5 parts, and the amount of phthalic anhydride polyester polyol added is 1.5 parts.

[0036] Example 5 The only difference between this embodiment and Embodiment 2 is that in this embodiment, 10 parts of ethylene-butyl acrylate-carbonyl terpolymer and 5 parts of phthalic anhydride polyester polyol are added.

[0037] Example 6 The only difference between this embodiment and Embodiment 2 is that in this embodiment, the amount of ethylene-butyl acrylate-carbonyl terpolymer added is 12.5 parts, and the amount of phthalic anhydride polyester polyol added is 2.5 parts.

[0038] Example 7 The only difference between this embodiment and Example 6 is that in this embodiment, the pyrophyllite powder is modified pyrophyllite powder. The preparation method of modified pyrophyllite powder includes the following steps: dissolving 3 parts of isopropyltris(dioctylpyrophosphoryloxy)titanate in 50 parts of isopropanol, adding 30 parts of pyrophyllite powder, and drying to obtain modified pyrophyllite powder.

[0039] Example 8 The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the pyrophyllite powder is modified pyrophyllite powder, and the preparation method of the modified pyrophyllite powder includes the following steps: 30 parts of pyrophyllite powder and 3 parts of vinyl chloride-vinyl acetate copolymer were blended, melted, dried, and pulverized to obtain modified pyrophyllite powder.

[0040] Example 9 The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the pyrophyllite powder is modified pyrophyllite powder, and the preparation method of the modified pyrophyllite powder includes the following steps: A1. Dissolve 0.6 parts of isopropyltris(dioctylpyrophosphoryloxy)titanate in 50 parts of isopropanol, add 30 parts of pyrophyllite powder, and dry to obtain pretreated pyrophyllite powder. A2. The pretreated pyrophyllite powder and 2.4 parts of vinyl chloride-vinyl acetate copolymer were blended, melted, dried and pulverized to obtain modified pyrophyllite powder.

[0041] Example 10 The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the pyrophyllite powder is modified pyrophyllite powder, and the preparation method of the modified pyrophyllite powder includes the following steps: A1. Dissolve 1 part of isopropyltris(dioctylpyrophosphoryloxy)titanate in 50 parts of isopropanol, add 30 parts of pyrophyllite powder, and dry to obtain pretreated pyrophyllite powder. A2. The pretreated pyrophyllite powder and 4 parts of vinyl chloride-vinyl acetate copolymer were blended, melted, dried and pulverized to obtain modified pyrophyllite powder.

[0042] Example 11 The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the pyrophyllite powder is modified pyrophyllite powder, and the preparation method of the modified pyrophyllite powder includes the following steps: A1. Dissolve 1.4 parts of isopropyltris(dioctylpyrophosphoryloxy)titanate in 50 parts of isopropanol, add 30 parts of pyrophyllite powder, and dry to obtain pretreated pyrophyllite powder. A2. The pretreated pyrophyllite powder and 5.6 parts of vinyl chloride-vinyl acetate copolymer were blended, melted, dried and pulverized to obtain modified pyrophyllite powder.

[0043] Comparative Example 1 The only difference between this comparative example and Example 1 is that, in this comparative example, phthalic anhydride polyester polyol is replaced with an equal amount of polypropylene adipate.

[0044] Comparative Example 2 The only difference between this comparative example and Example 1 is that, in this comparative example, the ethylene-butyl acrylate-carbonyl terpolymer is replaced with an equal amount of ethylene-vinyl acetate copolymer.

[0045] Comparative Example 3 The only difference between this comparative example and Example 1 is that neither the ethylene-n-butyl acrylate-carbonyl terpolymer nor the phthalic anhydride polyester polyol was added in this comparative example.

[0046] Experimental Example 1 Samples were cut from the sheath of the low-temperature resistant low-voltage power cables prepared in Examples 1-6 and Comparative Examples 1-3, and the elongation at break under low temperature of -40℃ was tested according to the method in GB / T 2951.14-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 14: General Test Methods for Low Temperature Tests". The test results are shown in Table 1.

[0047] Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-3

[0048] Compared with Comparative Examples 1-3, the elongation at break of the low-temperature low-voltage power cable sheath layer in Examples 1-6 was improved under low-temperature tensile testing at -40°C. This indicates that the addition of ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol to the sheath layer, through the combined use of ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol, can effectively improve the low-temperature resistance of the power cable sheath layer.

[0049] Compared with Examples 2 and 4, the elongation at break of the low-temperature low-voltage power cable sheath layer in Examples 5 and 6 was improved under low-temperature tensile stress at -40°C. This indicates that by optimizing the content ratio of ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol, when the weight ratio of ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol is 2 to 5:1, the low-temperature resistance of the power cable sheath layer can be further improved.

[0050] Experiment Example 2 Three samples were cut from the sheath of each of the low-temperature and low-voltage power cables prepared in Examples 6-11. The samples were prepared into dumbbell-shaped specimens with a thickness of 2 mm according to the method in GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Cables - Part 11: General Test Methods for Thickness and Dimensional Measurement and Mechanical Properties Test". The tensile strength was tested and the test results are shown in Table 2.

[0051] Table 2 Performance test results of Examples 6-11

[0052] Compared with Examples 6-8, the tensile strength of the low-temperature and low-voltage power cable sheath prepared in Examples 9-11 is improved, indicating that the surface modification treatment of pyrophyllite powder with titanate coupling agent and vinyl chloride-vinyl acetate copolymer can be used to obtain modified pyrophyllite powder, which can be added to the sheath layer to improve the mechanical strength of the sheath layer and increase its tensile strength to above 25.1 MPa.

[0053] 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-temperature resistant, low-voltage power cable, characterized in that, From the inside out, it comprises an insulated core, a shielding layer, and a sheathing layer. The insulated core consists of a conductor and an insulating layer covering the conductor. The insulating layer is a cross-linked polyethylene insulating layer. The sheathing layer comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5-13 parts ethylene propylene diene monomer (EPDM) rubber, 4-8 parts polyurethane elastomer, 15-25 parts filler, 4-6 parts stabilizer, 10-15 parts cold-resistant additive, 6-10 parts plasticizer, and 15-21 parts flame retardant; The cold-resistant additives include ethylene-n-butyl acrylate-carbonyl terpolymer and phthalic anhydride polyester polyol in a weight ratio of 1 to 9:

1.

2. The low-temperature resistant low-voltage power cable according to claim 1, characterized in that, The weight ratio of the ethylene-butyl acrylate-carbonyl terpolymer to the phthalic anhydride polyester polyol is 2~5:

1.

3. The low-temperature resistant low-voltage power cable according to claim 1, characterized in that, The number average molecular weight of the phthalic anhydride polyester polyol is 1000~2500.

4. The low-temperature resistant low-voltage power cable according to claim 1, characterized in that, The filler includes one or more of the following: calcium carbonate, silica, barium sulfate, kaolin, talc, mica powder, pyrophyllite powder, and attapulgite.

5. A low-temperature resistant low-voltage power cable according to claim 4, characterized in that, When the filler is pyrophyllite powder, the pyrophyllite powder is modified pyrophyllite powder; The raw materials for the modified pyrophyllite powder include pyrophyllite powder, titanate coupling agent, and vinyl chloride-vinyl acetate copolymer.

6. A low-temperature resistant low-voltage power cable according to claim 5, characterized in that, In the raw materials of the modified pyrophyllite powder, the weight ratio of the titanate coupling agent and the vinyl chloride-vinyl acetate copolymer to the pyrophyllite powder is 3~7:

30.

7. A low-temperature resistant low-voltage power cable according to claim 5, characterized in that, The preparation method of the modified pyrophyllite powder includes the following steps: A1. After preparing the titanate coupling agent into a solution, add pyrophyllite powder and dry to obtain pretreated pyrophyllite powder. A2. The pretreated pyrophyllite powder and vinyl chloride-vinyl acetate copolymer are blended, melted, dried, and pulverized to obtain modified pyrophyllite powder.

8. A low-temperature resistant low-voltage power cable according to claim 1, characterized in that, The conductor is made of either aluminum alloy or copper alloy. The shielding layer is a copper wire braided shielding layer.

9. A low-temperature resistant low-voltage power cable according to claim 1, characterized in that, The sheath layer also includes 1-3 parts of antioxidant and 4-6 parts of compatibilizer.

10. A method for preparing a low-temperature resistant low-voltage power cable, used to prepare a low-temperature resistant low-voltage power cable as described in any one of claims 1 to 9, characterized in that, Includes the following steps: An insulating layer is wrapped around the conductor to obtain an insulated core; after a shielding layer is set on the surface of the insulated core, the components of the sheath layer are blended and extruded to cover the outer periphery of the shielding layer to obtain a low-temperature and low-voltage power cable.

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