High-flame-retardant low-voltage power cable

Abstract

The invention relates to the technical field of cables, and provides a high-flame-retardant low-voltage power cable which sequentially comprises a conductor, an insulating layer and a sheath layer from inside to outside. The sheath layer is prepared from the following raw material components in parts by weight: 85 parts of ethylene-vinyl acetate copolymer, 65-75 parts of polyethylene, 30-40 parts of silicone rubber, 50-60 parts of a flame retardant, 3-5 parts of an activating agent, 2-4 parts of a lubricating agent, 2-4 parts of a vulcanizing agent, 1-3 parts of a vulcanizing aid and 1-3 parts of an antioxidant; the flame retardant is prepared from the following raw material components in parts by weight: 7 to 8 parts of 5-hydroxymethylfurfural, 3 to 4 parts of phenylguanidine carbonate and 40 to 50 parts of ammonium polyphosphate. According to the technical scheme, the problem of insufficient flame retardance of the sheath layer in the prior art is solved.

Description

Technical Field

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

[0002] Low-voltage power cables, as the core carrier in power transmission and distribution systems, are widely used in industrial plants, high-rise buildings, municipal engineering projects, rail transit, and residential communities, undertaking the important task of transmitting low-voltage electrical energy over short distances. However, with the acceleration of urbanization, the improvement of industrial automation, and the rapid development of the new energy industry, the load density of power systems continues to increase, and various electrical equipment places higher demands on power supply stability, safety, and cable lifespan.

[0003] Currently, while the sheathing materials of low-voltage power cables possess certain mechanical protection and insulation properties, their flame retardancy is often insufficient. Once the cable ignites due to overload, short circuit, or external fire source, the flames can spread rapidly along the cable line, even igniting surrounding combustibles and causing catastrophic consequences. Therefore, developing a low-voltage power cable with high flame retardancy is of great significance. Summary of the Invention

[0004] This invention proposes a high flame-retardant low-voltage power cable, which solves the problem of insufficient flame retardancy of the sheath layer in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a high flame-retardant low-voltage power cable, comprising, from the inside out, a conductor, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 85 parts of ethylene-vinyl acetate copolymer, 65-75 parts of polyethylene, 30-40 parts of silicone rubber, 50-60 parts of flame retardant, 3-5 parts of activator, 2-4 parts of lubricant, 2-4 parts of vulcanizing agent, 1-3 parts of vulcanizing aid, and 1-3 parts of antioxidant; The flame retardant comprises the following components by weight: 7-8 parts of 5-hydroxymethylfurfural, 3-4 parts of phenylguanidine carbonate, and 40-50 parts of ammonium polyphosphate.

[0006] As a further technical solution, the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate and ammonium polyphosphate is 4:6:40~50, for example, it can be 4:6:40, 4:6:45, 4:6:50, preferably 4:6:45.

[0007] This invention further improves the flame retardancy of the sheath layer by limiting the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate to 4:6:40~50. If the amount of ammonium polyphosphate is less than the above range, it will lead to insufficient acid source supply, and the amount of superphosphoric acid generated at high temperature will not be able to fully promote the carbonization of 5-hydroxymethylfurfural, resulting in the flame retardancy of the sheath layer not being further improved. If the amount of ammonium polyphosphate is more than the above range, the excess ammonium polyphosphate will agglomerate, resulting in uneven distribution of the carbon layer, which in turn will prevent the flame retardancy of the sheath layer from being further improved.

[0008] As a further technical solution, the preparation method of the flame retardant includes the following steps: A1. After uniformly dispersing 5-hydroxymethylfurfural in solvent I, premix I is obtained; after uniformly dispersing phenylguanidine carbonate in solvent II, premix II is obtained; after uniformly dispersing ammonium polyphosphate in solvent III, premix III is obtained. A2. After adding premixed solution II to premixed solution I and reacting, premixed solution IV is obtained. A3. After mixing premixed liquid III with premixed liquid IV, the mixture is concentrated and dried to obtain the flame retardant.

[0009] As a further technical solution, in step A2, the reaction temperature is 80~90℃ and the reaction time is 7~8h.

[0010] As a further technical solution, in step A3, the mixing temperature is 80~90℃ and the mixing time is 2~3h.

[0011] As a further technical solution, the silicone rubber includes methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber.

[0012] This invention improves the tensile strength of the cable sheath by adding methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber compounded as silicone rubber. Methyl vinyl phenyl silicone rubber, due to the phenyl groups introduced into its molecular chain, enhances the rigidity of the molecular chain and the intermolecular forces, which can effectively improve the tensile strength of the sheath. Methyl vinyl silicone rubber has excellent vulcanization and crosslinking activity, and can form a dense crosslinking network under the action of vulcanizing agent. After the two are compounded, the rigidity of the molecular chain of methyl vinyl phenyl silicone rubber combined with the dense crosslinking network provided by methyl vinyl silicone rubber synergistically improves the tensile strength of the sheath.

[0013] As a further technical solution, the phenyl molar content in the methyl vinyl phenyl silicone rubber is 8%~13%; the vinyl molar content in the methyl vinyl silicone rubber is 0.13%~0.18%.

[0014] As a further technical solution, the mass ratio of the methyl vinyl phenyl silicone rubber to the methyl vinyl silicone rubber is 5:6~8, for example, it can be 5:6, 5:7, 5:8, preferably 5:7.

[0015] As a further technical solution, the lubricant is polyethylene wax.

[0016] As a further technical solution, the activator includes one or more of zinc oxide, stearic acid, and zinc stearate.

[0017] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1035.

[0018] As a further technical solution, the vulcanization aid includes triallyl isocyanurate.

[0019] As a further technical solution, the vulcanizing agent includes one or both of benzoyl peroxide and tert-butyl peroxide.

[0020] The working principle and beneficial effects of this invention are as follows: This invention provides a high flame-retardant low-voltage power cable that improves the flame retardancy of the sheath layer by adding ammonium polyphosphate modified with 5-hydroxymethylfurfural and phenylguanidine carbonate as a flame retardant. Ammonium polyphosphate is a widely used flame retardant; however, when used alone, it suffers from easy agglomeration and insufficient flame retardancy. Therefore, it is modified by 5-hydroxymethylfurfural and phenylguanidine carbonate. After the reaction of 5-hydroxymethylfurfural and phenylguanidine carbonate, the hydroxyl and amino groups on the surface of the ammonium polyphosphate act on it, which not only improves the dispersibility of the ammonium polyphosphate, but also promotes the dehydration and carbonization of the product after the reaction of 5-hydroxymethylfurfural and phenylguanidine carbonate under high temperature conditions, thus promoting the formation of a carbon layer. At the same time, it releases ammonia and nitrogen, diluting the concentration of oxygen and combustible gases, thereby playing an oxygen-barrier role and further improving the flame retardancy of the sheath layer. Detailed Implementation

[0021] 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.

[0022] In the following examples and comparative examples: Ethylene-vinyl acetate copolymer, model 33-45; Polyethylene, model: LD100AC; Methyl vinyl phenyl silicone rubber with phenyl molar content of 8%~13%, model: MY120; Methyl vinyl silicone rubber with vinyl molar content of 0.13%~0.18%, model: 110-2; Polyethylene wax, model: LP0040P; Ammonium polyphosphate, model: TY-423, degree of polymerization 1000.

[0023] Example 1 A high flame-retardant low-voltage power cable comprises, from the inside out, a conductor, an insulation layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 85 parts ethylene-vinyl acetate copolymer, 65 parts polyethylene, 30 parts silicone rubber, 50 parts flame retardant, 2 parts zinc oxide, 1 part stearic acid, 2 parts polyethylene wax, 2 parts benzoyl peroxide, 1 part triallyl isocyanurate, and 1 part antioxidant 1010. The silicone rubber is methyl vinyl silicone rubber. The preparation method of flame retardant includes the following steps: A1. 5-Hydroxymethylfurfural is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of 5-hydroxymethylfurfural to anhydrous ethanol is 1 g:10 mL) to obtain premix I; phenylguanidine carbonate is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of phenylguanidine carbonate to anhydrous ethanol is 1 g:10 mL) to obtain premix II; ammonium polyphosphate is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of ammonium polyphosphate to anhydrous ethanol is 1 g:5 mL) to obtain premix III, wherein the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate is 4:6:40. A2. Add premixed solution II to premixed solution I and react under reflux at 80°C for 8 hours to obtain premixed solution IV. A3. Add premixed liquid III to premixed liquid IV and mix under reflux at 80°C for 3 hours. Then concentrate and dry to obtain flame retardant. A method for preparing a high flame-retardant low-voltage power cable includes the following steps: S1. Extruding insulating material onto the outside of the conductor to form an insulating layer; S2. After the raw materials for the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the insulation layer, vulcanized, to form the sheath layer, thus obtaining a high flame-retardant low-voltage power cable.

[0024] Example 2 A high flame-retardant low-voltage power cable comprises, from the inside out, a conductor, an insulation layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 85 parts ethylene-vinyl acetate copolymer, 70 parts polyethylene, 35 parts silicone rubber, 55 parts flame retardant, 3 parts zinc oxide, 1 part stearic acid, 3 parts polyethylene wax, 3 parts benzoyl peroxide, 2 parts triallyl isocyanurate, and 2 parts antioxidant 1010. The silicone rubber is methyl vinyl silicone rubber. The preparation method of flame retardant includes the following steps: A1. 5-Hydroxymethylfurfural is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of 5-hydroxymethylfurfural to anhydrous ethanol is 1 g:10 mL) to obtain premix I; phenylguanidine carbonate is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of phenylguanidine carbonate to anhydrous ethanol is 1 g:10 mL) to obtain premix II; ammonium polyphosphate is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of ammonium polyphosphate to anhydrous ethanol is 1 g:5 mL) to obtain premix III, wherein the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate is 4:6:40. A2. Add premixed solution II to premixed solution I and react under reflux at 85°C for 7.5 h to obtain premixed solution IV; A3. Add premixed liquid III to premixed liquid IV and mix under reflux at 85°C for 2.5 hours. Then concentrate and dry to obtain flame retardant. A method for preparing a high flame-retardant low-voltage power cable includes the following steps: S1. Extruding insulating material onto the outside of the conductor to form an insulating layer; S2. After the raw materials for the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the insulation layer, vulcanized, to form the sheath layer, thus obtaining a high flame-retardant low-voltage power cable.

[0025] Example 3 A high flame-retardant low-voltage power cable comprises, from the inside out, a conductor, an insulation layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 85 parts ethylene-vinyl acetate copolymer, 75 parts polyethylene, 40 parts silicone rubber, 60 parts flame retardant, 3 parts zinc oxide, 2 parts stearic acid, 4 parts polyethylene wax, 4 parts benzoyl peroxide, 3 parts triallyl isocyanurate, and 3 parts antioxidant 1010. The silicone rubber is methyl vinyl silicone rubber. The preparation method of flame retardant includes the following steps: A1. 5-Hydroxymethylfurfural is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of 5-hydroxymethylfurfural to anhydrous ethanol is 1 g:10 mL) to obtain premix I; phenylguanidine carbonate is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of phenylguanidine carbonate to anhydrous ethanol is 1 g:10 mL) to obtain premix II; ammonium polyphosphate is uniformly dispersed in anhydrous ethanol (the mass-to-volume ratio of ammonium polyphosphate to anhydrous ethanol is 1 g:5 mL) to obtain premix III, wherein the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate is 4:6:40. A2. Add premixed solution II to premixed solution I and react under reflux at 90°C for 7 hours to obtain premixed solution IV. A3. Add premixed liquid III to premixed liquid IV and mix under reflux at 90°C for 2 hours. Then concentrate and dry to obtain flame retardant. A method for preparing a high flame-retardant low-voltage power cable includes the following steps: S1. Extruding insulating material onto the outside of the conductor to form an insulating layer; S2. After the raw materials for the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the insulation layer, vulcanized, to form the sheath layer, thus obtaining a high flame-retardant low-voltage power cable.

[0026] Example 4 The only difference between this embodiment and Embodiment 2 is that the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate in this embodiment is 4:6:45.

[0027] Example 5 The only difference between this embodiment and Embodiment 2 is that the mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate in this embodiment is 4:6:50.

[0028] Example 6 The only difference between this embodiment and Embodiment 2 is that the silicone rubber in this embodiment is methyl vinyl phenyl silicone rubber.

[0029] Example 7 The only difference between this embodiment and Embodiment 2 is that the silicone rubber in this embodiment is composed of methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber in a mass ratio of 5:6.

[0030] Example 8 The only difference between this embodiment and Embodiment 2 is that the silicone rubber in this embodiment is composed of methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber in a mass ratio of 5:7.

[0031] Example 9 The only difference between this embodiment and Embodiment 2 is that the silicone rubber in this embodiment is composed of methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber in a mass ratio of 5:8.

[0032] Comparative Example 1 The only difference between this comparative example and Example 1 is that the flame retardant in this comparative example is ammonium polyphosphate.

[0033] Comparative Example 2 The only difference between this comparative example and Example 1 is that the preparation method of the flame retardant includes the following steps: A1. After dispersing 5-hydroxymethylfurfural in anhydrous ethanol (the mass-to-volume ratio of 5-hydroxymethylfurfural to anhydrous ethanol is 1 g: 10 mL), a premix I is obtained; after dispersing ammonium polyphosphate in anhydrous ethanol (the mass-to-volume ratio of ammonium polyphosphate to anhydrous ethanol is 1 g: 5 mL), a premix II is obtained, wherein the mass ratio of 5-hydroxymethylfurfural to ammonium polyphosphate is 1:4. A2. Add premixed liquid II to premixed liquid I and mix under reflux at 80°C for 3 hours. Then concentrate and dry to obtain flame retardant.

[0034] Comparative Example 3 The only difference between this comparative example and Example 1 is that the preparation method of the flame retardant includes the following steps: A1. After uniformly dispersing phenylguanidine carbonate in anhydrous ethanol (the mass-volume ratio of phenylguanidine carbonate to anhydrous ethanol is 1g:10mL), premix solution I is obtained; after uniformly dispersing ammonium polyphosphate in anhydrous ethanol (the mass-volume ratio of ammonium polyphosphate to anhydrous ethanol is 1g:5mL), premix solution II is obtained, wherein the mass ratio of phenylguanidine carbonate to ammonium polyphosphate is 1:4. A2. Add premixed liquid II to premixed liquid I and mix under reflux at 80°C for 3 hours. Then concentrate and dry to obtain flame retardant.

[0035] Experimental Example 1 The sheath layers of the high flame-retardant low-voltage power cables prepared in Examples 1-9 and Comparative Examples 1-3 were tested according to the following method: 1. Flame retardant performance: The oxygen index was tested according to GB / T 2406.2-2009 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test". The sample shape was IV, and the ignition method was Method A, top surface ignition method. The test results are shown in Table 1 below. 2. Tensile strength: The tensile strength of the specimen was tested according to the method specified 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". The test specimen was a dumbbell specimen with a thickness of 1.5 mm and a moving speed of 25 mm / min. The test results are shown in Table 2 below. Table 1. Test results of flame retardant properties of the cable sheath in Examples 1-5 and Comparative Examples 1-3.

[0036] The oxygen index of Examples 1-5 is higher than that of Comparative Examples 1-3, indicating that the present invention improves the flame retardancy of the sheath layer of low-voltage power cables by adding ammonium polyphosphate modified with 5-hydroxymethylfurfural and phenylguanidine carbonate as a flame retardant.

[0037] Table 2. Test results of tensile strength performance of cable sheath in Examples 2, 6-9

[0038] The tensile strength of Examples 7-9 is higher than that of Examples 2 and 6, indicating that the present invention improves the tensile strength of the sheath layer of high flame retardant low voltage power cable by adding methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber compound as silicone rubber.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high flame-retardant low-voltage power cable, characterized in that, From the inside out, the components are a conductor, an insulating layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 85 parts ethylene-vinyl acetate copolymer, 65-75 parts polyethylene, 30-40 parts silicone rubber, 50-60 parts flame retardant, 3-5 parts activator, 2-4 parts lubricant, 2-4 parts vulcanizing agent, 1-3 parts vulcanizing aid, and 1-3 parts antioxidant. The flame retardant comprises the following components by weight: 7-8 parts of 5-hydroxymethylfurfural, 3-4 parts of phenylguanidine carbonate, and 40-50 parts of ammonium polyphosphate.

2. The high flame-retardant low-voltage power cable according to claim 1, characterized in that, The mass ratio of 5-hydroxymethylfurfural, phenylguanidine carbonate, and ammonium polyphosphate is 4:6:40~50.

3. The high flame-retardant low-voltage power cable according to claim 1, characterized in that, The method for preparing the flame retardant includes the following steps: A1. After uniformly dispersing 5-hydroxymethylfurfural in solvent I, premix I is obtained; after uniformly dispersing phenylguanidine carbonate in solvent II, premix II is obtained; after uniformly dispersing ammonium polyphosphate in solvent III, premix III is obtained. A2. After adding premixed solution II to premixed solution I and reacting, premixed solution IV is obtained. A3. After mixing premixed liquid III with premixed liquid IV, the mixture is concentrated and dried to obtain the flame retardant.

4. A high flame-retardant low-voltage power cable according to claim 3, characterized in that, In step A2, the reaction temperature is 80~90℃ and the reaction time is 7~8h.

5. A high flame-retardant low-voltage power cable according to claim 3, characterized in that, In step A3, the mixing temperature is 80~90℃ and the mixing time is 2~3h.

6. A high flame-retardant low-voltage power cable according to claim 1, characterized in that, The silicone rubber includes methyl vinyl phenyl silicone rubber and methyl vinyl silicone rubber.

7. A high flame-retardant low-voltage power cable according to claim 6, characterized in that, The mass ratio of the methyl vinyl phenyl silicone rubber to the methyl vinyl silicone rubber is 5:6~8.

8. A high flame-retardant low-voltage power cable according to claim 1, characterized in that, The activator includes one or more of zinc oxide, stearic acid, and zinc stearate.

9. A high flame-retardant low-voltage power cable according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1035.

10. A high flame-retardant low-voltage power cable according to claim 1, characterized in that, The vulcanizing agent includes one or both of benzoyl peroxide and tert-butyl peroxide.

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