Aging-resistant flame-retardant power cable

Abstract

The application relates to the technical field of power cables, and discloses an anti-aging and flame-retardant power cable which comprises, from inside to outside, a conductor, an insulation layer, an armored layer and a sheath layer, wherein the raw material of the sheath layer comprises the following components in parts by weight: 100 parts of linear low-density polyethylene, 2-3 parts of a photoinitiator, 0.2-0.5 parts of an antioxidant, 0.03-0.08 parts of a light stabilizer, 13-15 parts of a flame retardant and 5-6 parts of a filler; the flame retardant comprises the following components in parts by weight: 100 parts of talcum powder loaded with zinc stannate and 30-40 parts of magnesium hydroxide. Through the technical scheme, the problem of insufficient flame retardation and aging resistance of the sheath layer in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and more specifically, to an aging-resistant and flame-retardant power cable. Background Technology

[0002] As the core carrier of power transmission and distribution, the safety performance of power cables is directly related to the stable operation of the entire power network and public safety. With the accelerated urbanization process and the continuous growth of power load density in my country, the laying environment of power cables is becoming increasingly complex, especially in special application scenarios such as high-rise buildings, underground spaces, and rail transit. Therefore, the aging resistance and flame retardancy of power cables have become important technical indicators for ensuring the safe evacuation of personnel and the continuity of power supply to critical facilities. Against this backdrop, the market has placed high demands on both the aging resistance and flame retardancy of power cables.

[0003] Currently, most cables on the market possess certain flame-retardant and aging-resistant properties. However, when faced with fire risks such as high temperatures and accelerated flame spread in special scenarios like high-load, densely laid installations, high-rise buildings, underground spaces, and rail transit, their flame-retardant and aging-resistant properties (high aging resistance of the power cable sheath layer can prevent faults caused by sheath failure) become significantly insufficient, failing to meet the core requirements for safe operation. Therefore, developing power cables with high aging resistance and high flame retardancy has become an urgent need to address the fire hazards of traditional products and ensure the stable operation of power systems, and is also one of the important directions for technological development in the cable industry. Summary of the Invention

[0004] This invention proposes an aging-resistant and flame-retardant power cable, which solves the problem of insufficient flame retardancy and aging resistance of the sheath layer in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] This invention proposes an aging-resistant and flame-retardant power cable, which comprises, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts of linear low-density polyethylene, 2-3 parts of photoinitiator, 0.2-0.5 parts of antioxidant, 0.03-0.08 parts of light stabilizer, 13-15 parts of flame retardant, and 5-6 parts of filler. The flame retardant includes the following components by weight: 100 parts of talc-supported zinc stannate and 30-40 parts of magnesium hydroxide.

[0007] As a further technical solution, the raw materials for the talc-loaded zinc stannate include talc, sodium stannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate.

[0008] As a further technical solution, the mass ratio of talc, sodium hydroxystannate, zinc oxide, potassium hydroxide, urea and sodium polyacrylate is 10:1:1:7:10:0.1~0.3, preferably 10:1:1:7:10:0.2.

[0009] In this invention, the mass ratio of talc, sodium stannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate is specified as 10:1:1:7:10:0.1~0.3. This specific ratio ensures that zinc stannate is uniformly loaded on the surface of talc, thereby forming a stable coating structure, improving the flame retardancy of zinc stannate loaded on talc, and thus improving the flame retardancy of the sheath layer.

[0010] As a further technical solution, the weight-average molecular weight of the sodium polyacrylate is 2400~4300, for example, it can be 2400, 3800, or 4300.

[0011] In this invention, by limiting the molecular weight of sodium polyacrylate to 2400-4300, it can exert a dispersing effect during the preparation of talc-loaded zinc stannate, further improving the flame retardancy of talc-loaded zinc stannate. If the molecular weight of sodium polyacrylate is lower than 2400 or greater than 4300, its molecular chain is too short, resulting in insufficient adsorption capacity, while the molecular chain segments are too long and intertwine, leading to a decrease in the dispersion effect. This makes it impossible to fully solve the problem of talc agglomeration, resulting in insufficient contact between the precursor of zinc stannate (sodium hydroxystannate, zinc oxide, etc.) and talc, making it impossible for zinc stannate to fully load talc or resulting in excessive local coating. When the molecular weight of sodium polyacrylate is 2400-4300, zinc stannate can be uniformly coated with talc, further exerting the flame retardant effect of zinc stannate, thereby further improving the flame retardancy of the power cable sheath layer.

[0012] As a further technical solution, the preparation method of the talc-supported zinc stannate includes the following steps:

[0013] A1. The talc powder, urea and sodium polyacrylate are added to solvent I and mixed to obtain mixture I;

[0014] A2. The sodium hydroxystannate, zinc oxide and potassium hydroxide are added to solvent II and mixed. Then, mixture I is added and mixed. After filtration, washing, drying and calcination, talc-supported zinc stannate is obtained.

[0015] As a further technical solution, both solvent I and solvent II are water.

[0016] As a further technical solution, in step A2, the temperature of the added mixture I is 80~90℃, and the mixing time of the added mixture I is 7~9h.

[0017] As a further technical solution, the photoinitiator includes benzophenone and photoinitiator 1000.

[0018] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0019] As a further technical solution, the light stabilizer is a hindered amine light stabilizer, which includes one or two of light stabilizer 770 and light stabilizer 944.

[0020] In this invention, the addition of hindered amine light stabilizers can effectively improve the light aging resistance of the sheath layer. By capturing free radicals generated under ultraviolet irradiation and decomposing hydrogen peroxide, it can inhibit the photo-oxidative breakage of linear low-density polyethylene molecular chains, reduce aging phenomena such as cracking, embrittlement, and discoloration of the sheath layer caused by long-term light exposure, extend the service life of the cable sheath layer, and ensure the stable operation of power cables.

[0021] As a further technical solution, the filler includes one or more of carbon black, calcium carbonate, and kaolin.

[0022] The working principle and beneficial effects of this invention are as follows:

[0023] This invention provides an aging-resistant and flame-retardant power cable whose sheath layer uses talc-loaded zinc stannate and magnesium hydroxide as flame retardants, improving the aging resistance and flame retardancy of the cable sheath layer. Zinc stannate is difficult to disperse uniformly in the matrix material of the sheath layer. However, talc-loaded zinc stannate solves the problem of zinc stannate's easy agglomeration and poor dispersibility by uniformly loading zinc stannate onto the lamellar structure of talc, fully utilizing the flame-retardant effect of zinc stannate while reducing its application cost. Furthermore, talc also has excellent aging resistance, thus achieving a simultaneous improvement in flame retardancy and aging resistance. In addition, zinc stannate can synergistically promote coke formation with magnesium hydroxide. The magnesium oxide produced by the decomposition of magnesium hydroxide at high temperatures can also form an inorganic coating layer, creating a double barrier with the lamellar structure of talc, further blocking heat transfer and oxygen contact, and improving the flame-retardant performance of the sheath layer. This comprehensively ensures the safety and lifespan of the cable in complex environments. 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:

[0026] Linear low-density polyethylene, model: FM5220, manufacturer: Borouge Corporation;

[0027] Carbon black: average particle size 2000 mesh;

[0028] Talc: Average particle size 500nm;

[0029] Magnesium hydroxide: average particle size 500 nm;

[0030] Sodium polyacrylate with a weight-average molecular weight of 1400, model: PAA1KBR; manufacturer: Shanghai Zhenzhun Biotechnology Co., Ltd.

[0031] Sodium polyacrylate with a weight-average molecular weight of 2400, model: PAA3K; manufacturer: Shanghai Zhenzhun Biotechnology Co., Ltd.

[0032] Sodium polyacrylate with a weight-average molecular weight of 4300, model: PAA4KBR; manufacturer: Shanghai Zhenzhun Biotechnology Co., Ltd.

[0033] Sodium polyacrylate with a weight-average molecular weight of 5660, model: PAA5K; manufacturer: Shanghai Zhenzhun Biotechnology Co., Ltd.

[0034] Example 1

[0035] An aging-resistant and flame-retardant power cable comprises, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer;

[0036] The raw materials for the sheath layer include the following components by weight: 100 parts linear low-density polyethylene, 0.8 parts benzophenone, 1.2 parts photoinitiator 1000, 0.2 parts antioxidant 1010, 0.03 parts light stabilizer 770, 13 parts flame retardant, and 5 parts carbon black. The flame retardant includes the following components by weight: 100 parts talc-supported zinc stannate and 30 parts magnesium hydroxide.

[0037] The preparation method of talc-supported zinc stannate includes the following steps:

[0038] A1. Add talc, urea and sodium polyacrylate to water (the mass-volume ratio of talc to water is 1g:7mL) and mix at 50℃ for 1h to obtain mixture I, wherein the weight-average molecular weight of sodium polyacrylate is 5660.

[0039] A2. Sodium hydroxystannate, zinc oxide, and potassium hydroxide were added to water (the mass-volume ratio of potassium hydroxide to water was 1 g: 6 mL), and then mixed with mixture I. The mixture was stirred at 85°C for 8 h, filtered, washed with water, dried, and then calcined at 600°C for 2 h to obtain talc-supported zinc stannate. The mass ratio of talc, sodium hydroxystannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate was 10:1:1:7:10:0.1.

[0040] A method for preparing an aging-resistant and flame-retardant power cable includes the following steps:

[0041] S1. Extruding insulating material around the conductor to form an insulating layer;

[0042] S2. Wrap the armor layer material around the insulation layer to form the armor layer;

[0043] S3. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer. The sheath layer is then placed in an ultraviolet irradiation crosslinking device for ultraviolet irradiation crosslinking to form an sheath layer, thus obtaining an aging-resistant and flame-retardant power cable.

[0044] The process parameters for ultraviolet irradiation crosslinking are as follows: ultraviolet wavelength is 380 nm, and ultraviolet intensity is 9.5 W / cm². 2 .

[0045] Example 2

[0046] An aging-resistant and flame-retardant power cable comprises, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer;

[0047] The raw materials for the sheath layer include the following components by weight: 100 parts linear low-density polyethylene, 1.2 parts benzophenone, 1.3 parts photoinitiator 1000, 0.3 parts antioxidant 1010, 0.05 parts light stabilizer 770, 14 parts flame retardant, and 5.5 parts carbon black. The flame retardant includes the following components by weight: 100 parts talc-supported zinc stannate and 35 parts magnesium hydroxide.

[0048] The preparation method of talc-supported zinc stannate includes the following steps:

[0049] A1. Add talc, urea and sodium polyacrylate to water (the mass-volume ratio of talc to water is 1g:7mL) and mix at 50℃ for 1h to obtain mixture I, wherein the weight-average molecular weight of sodium polyacrylate is 5660.

[0050] A2. Sodium stannate, zinc oxide, and potassium hydroxide were added to water (the mass-volume ratio of potassium hydroxide to water was 1 g: 6 mL), and then mixed with mixture I. The mixture was stirred at 85°C for 8 hours, filtered, washed with water, dried, and then calcined at 600°C for 2 hours to obtain talc-supported zinc stannate. The mass ratio of talc, sodium hydroxystannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate was 10:1:1:7:10:0.2.

[0051] A method for preparing an aging-resistant and flame-retardant power cable includes the following steps:

[0052] S1. Extruding insulating material around the conductor to form an insulating layer;

[0053] S2. Wrap the armor layer material around the insulation layer to form the armor layer;

[0054] S3. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer. The sheath layer is then placed in an ultraviolet irradiation crosslinking device for ultraviolet irradiation crosslinking to form an sheath layer, thus obtaining an aging-resistant and flame-retardant power cable.

[0055] The process parameters for ultraviolet irradiation crosslinking are as follows: ultraviolet wavelength is 380 nm, and ultraviolet intensity is 9.5 W / cm². 2 .

[0056] Example 3

[0057] An aging-resistant and flame-retardant power cable comprises, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts linear low-density polyethylene, 1.3 parts benzophenone, 1.7 parts photoinitiator 1000, 0.5 parts antioxidant 1010, 0.08 parts light stabilizer 770, 15 parts flame retardant, and 6 parts carbon black. The flame retardant includes the following components by weight: 100 parts talc-supported zinc stannate and 40 parts magnesium hydroxide.

[0058] The preparation method of talc-supported zinc stannate includes the following steps:

[0059] A1. Add talc, urea and sodium polyacrylate to water (the mass-volume ratio of talc to water is 1g:7mL) and mix at 50℃ for 1h to obtain mixture I, wherein the weight-average molecular weight of sodium polyacrylate is 5660.

[0060] A2. Sodium hydroxystannate, zinc oxide, and potassium hydroxide were added to water (the mass-volume ratio of potassium hydroxide to water was 1 g: 6 mL), and then mixed with mixture I. The mixture was stirred at 85°C for 8 h, filtered, washed with water, dried, and then calcined at 600°C for 2 h to obtain talc-supported zinc stannate. The mass ratio of talc, sodium hydroxystannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate was 10:1:1:7:10:0.3.

[0061] A method for preparing an aging-resistant and flame-retardant power cable includes the following steps:

[0062] S1. Extruding the insulating material onto the outside of the insulating layer to form an insulating layer;

[0063] S2. Wrap the armor layer material around the insulation layer to form the armor layer;

[0064] S3. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer. The sheath layer is then placed in an ultraviolet irradiation crosslinking device for ultraviolet irradiation crosslinking to form an sheath layer, thus obtaining an aging-resistant and flame-retardant power cable.

[0065] The process parameters for ultraviolet irradiation crosslinking are as follows: ultraviolet wavelength is 380 nm, and ultraviolet intensity is 9.5 W / cm². 2 .

[0066] Example 4

[0067] The only difference between this embodiment and Embodiment 2 is that the amount of magnesium hydroxide added in this embodiment is 35 parts.

[0068] Example 5

[0069] The only difference between this embodiment and Embodiment 2 is that the amount of magnesium hydroxide added in this embodiment is 40 parts.

[0070] Example 6

[0071] The only difference between this embodiment and Embodiment 2 is that sodium polyacrylate is not added in this embodiment.

[0072] Example 7

[0073] The only difference between this embodiment and Embodiment 2 is that the weight-average molecular weight of sodium polyacrylate in this embodiment is 1400.

[0074] Example 8

[0075] The only difference between this embodiment and Embodiment 7 is that the weight-average molecular weight of sodium polyacrylate in this embodiment is 4300.

[0076] Example 9

[0077] The only difference between this embodiment and Embodiment 7 is that the weight-average molecular weight of sodium polyacrylate in this embodiment is 2400.

[0078] Comparative Example 1

[0079] The only difference between this comparative example and Example 2 is that in this comparative example, talc-loaded zinc stannate is replaced with an equal mass of magnesium hydroxide.

[0080] Comparative Example 2

[0081] The only difference between this comparative example and Example 2 is that in this comparative example, magnesium hydroxide is replaced with an equal mass of talc-supported zinc stannate.

[0082] Comparative Example 3

[0083] The only difference between this comparative example and Example 6 is that in this comparative example, talc-supported zinc stannate is replaced with an equal amount of zinc stannate composite talc. The preparation method of zinc stannate composite talc includes the following steps:

[0084] A1. Add urea, sodium stannate, zinc oxide and potassium hydroxide to water and mix at 85°C for 8 hours. After filtration, drying and calcination at 600°C for 2 hours, zinc stannate is obtained.

[0085] A2. Zinc stannate and talc are mixed to obtain zinc stannate composite talc powder;

[0086] The mass ratio of talc, sodium stannate, zinc oxide, potassium hydroxide, and urea is 10:1:1:7:10.

[0087] Experimental Example 1

[0088] The sheath layers of the aging-resistant and flame-retardant power cables prepared in Examples 1-9 and Comparative Examples 1-3 were tested according to the following method:

[0089] Flame retardant performance: The oxygen index was tested according to Method A of GB / T 2406.2-2009 "Determination of burning behavior by oxygen index method for plastics - Part 2: Room temperature test". The sample shape was IV. The test results are shown in Table 1 and Table 2 below.

[0090] Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-3

[0091]

[0092] The oxygen index of Examples 1-6 is higher than that of Comparative Examples 1-3, indicating that the present invention improves the flame retardancy of the sheath layer by adding talc-loaded zinc stannate and magnesium hydroxide as a flame retardant.

[0093] Table 2 Performance test results of Examples 2 and 7-9

[0094]

[0095] The oxygen index of Examples 8 and 9 is higher than that of Examples 2 and 7, indicating that the present invention further improves the flame retardancy of the sheath layer by limiting the molecular weight of sodium polyacrylate to 2400-4300.

[0096] Experimental Example 2

[0097] The sheath layers of the aging-resistant and flame-retardant power cables prepared in Examples 1-3 were tested according to the following method:

[0098] Mechanical properties: Tensile strength was tested according to GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 11: General Test Methods - Thickness and Dimensional Measurements - Mechanical Properties Tests". The test specimen was a dumbbell specimen with a thickness of 1.5 mm and a moving speed of 25 mm / min; according to GB / T 7141 After conducting the thermal aging test according to the 2008 "Test Method for Thermal Aging of Plastics", the tensile strength was then tested according to the above-mentioned tensile strength test method. Among them, when conducting the thermal aging test, Method B was used, the temperature was 90℃ and the time was 128h. The test results are shown in Table 3 below.

[0099] Table 3 Performance test results of Examples 1-3

[0100]

[0101] As can be seen from Examples 1-3 in Table 3, the sheath layer of the present invention has good heat aging resistance.

[0102] 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. An aging-resistant and flame-retardant power cable, characterized in that, From the inside out, it includes a conductor, an insulating layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts linear low-density polyethylene, 2-3 parts photoinitiator, 0.2-0.5 parts antioxidant, 0.03-0.08 parts light stabilizer, 13-15 parts flame retardant, and 5-6 parts filler. The flame retardant includes the following components by weight: 100 parts talc-supported zinc stannate and 30-40 parts magnesium hydroxide. The raw materials for the talc-loaded zinc stannate include talc, sodium hydroxystannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate. The weight-average molecular weight of the sodium polyacrylate is 2400~4300; The preparation method of the talc-supported zinc stannate includes the following steps: A1. The talc powder, urea and sodium polyacrylate are added to solvent I and mixed to obtain mixture I; A2. The sodium stannate, zinc oxide and potassium hydroxide are added to solvent II and mixed. Then, mixture I is added and mixed. After filtration, washing, drying and calcination, talc-supported zinc stannate is obtained. Both solvent I and solvent II are water.

2. The aging-resistant and flame-retardant power cable according to claim 1, characterized in that, The mass ratio of talc, sodium hydroxystannate, zinc oxide, potassium hydroxide, urea, and sodium polyacrylate is 10:1:1:7:10:0.1~0.

3.

3. The aging-resistant and flame-retardant power cable according to claim 1, characterized in that, In step A2, the temperature at which the added mixture I is mixed is 80~90℃, and the mixing time of the added mixture I is 7~9h.

4. The aging-resistant and flame-retardant power cable according to claim 1, characterized in that, The photoinitiator includes benzophenone and photoinitiator 1000.

5. The aging-resistant and flame-retardant power cable according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

6. The aging-resistant and flame-retardant power cable according to claim 1, characterized in that, The light stabilizer is a hindered amine light stabilizer, which includes one or two of light stabilizer 770 and light stabilizer 944.

7. The aging-resistant and flame-retardant power cable according to claim 1, characterized in that, The filler includes one or more of carbon black, calcium carbonate, and kaolin.

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