High-flame-retardant cable

Abstract

The invention relates to the technical field of cables, and provides a high-flame-retardant cable which is composed of three layers including a conductor, an insulating layer and a protective layer from inside to outside, and the protective layer comprises the following raw materials in parts by weight: 40-60 parts of chloroprene rubber, 5-15 parts of ethylene-vinyl acetate copolymer, 10-12 parts of a flame retardant aid, 1-3 parts of aluminum oxide, 2-8 parts of diphenyl phosphamide, 0.1-0.5 part of a cross-linking agent and 0.3-0.6 part of an antioxidant. And the flame retardant auxiliary agent is a siloxane compound. According to the technical scheme, the problems of low heat resistance and poor flame retardant effect of the cable in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and specifically, to a highly flame-retardant cable. Background Art

[0002] A cable is a conductive line formed by combining one or more insulated conductors and then wrapping them with insulating materials. It usually consists of a conductor, an insulating layer, and a protective layer. Cables play a crucial role in modern society and are an essential part in multiple fields such as power transmission, communication, and control systems. When selecting a cable, especially in places with a high fire risk, such as commercial buildings, industrial facilities, tunnels, and subways, it is very necessary to use a cable with flame-retardant properties. Flame-retardant cables can not only maintain their structural integrity in high-temperature or fire environments, avoid more extensive equipment damage caused by cable short circuits, and ensure the stability of the power supply system, but also significantly reduce the risk of fire and slow down the spread of flames, thereby gaining more time for personnel evacuation and fire extinguishing. In a high-temperature environment, if the insulating material of the cable does not have heat resistance, it will cause the cable to soften, deform, or age, thereby triggering safety hazards such as short circuits and electric leakage. During use, when current passes through the cable, heat will be generated. If the cable does not have sufficient heat resistance, the overloaded current may cause the cable temperature to rise, leading to damage and fire risks. Therefore, it is an urgent problem to be solved at present to prepare a cable with heat resistance and high flame retardancy. Summary of the Invention

[0003] The present invention provides a highly flame-retardant cable, which solves the problems of low heat resistance and poor flame-retardant effect of cables in the related art.

[0004] The technical solution of the present invention is as follows: The present invention provides a highly flame-retardant cable, which consists of three layers. From the inside to the outside, they are a conductor, an insulating layer, and a protective layer in sequence. The protective layer comprises raw materials with the following parts by weight: 100 parts of chloroprene rubber, 5 - 15 parts of ethylene-vinyl acetate copolymer, 10 - 12 parts of flame-retardant auxiliary agent, 10 - 18 parts of alumina, 2 - 8 parts of diphenylphosphoramide, 0.1 - 0.5 parts of crosslinking agent, and 0.3 - 0.6 parts of antioxidant. The flame-retardant auxiliary agent is a siloxane compound.

[0005] As a further technical solution, the material of the conductor is copper.

[0006] As a further technical solution, the insulating layer is an ethylene-propylene rubber insulating layer.

[0007] As a further technical solution, the flame-retardant auxiliary agent consists of siloxane compounds with different carbon chain lengths.

[0008] As a further technical solution, the siloxane compound consists of ethyltrimethoxysilane and octadecyltrimethoxysilane.

[0009] As a further technical solution, the mass ratio of the ethyltrimethoxysilane to the octadecyltrimethoxysilane is 3-5:1.

[0010] As a further technical solution, the mass ratio of the ethyltrimethoxysilane to the octadecyltrimethoxysilane is 4:1.

[0011] In the present invention, siloxane compounds with long and short chain lengths are mixed and used. The short-chain siloxane has high fluidity and can fill the gaps between materials, increasing the density of the materials, thereby reducing the smoke and harmful gas emissions during combustion and improving environmental friendliness; the longer-chain siloxane usually has good flexibility and ductility, and can form a stable three-dimensional network structure at high temperatures, effectively preventing the spread of flames and slowing down the heat conduction, thereby improving the flame retardancy of the materials. Through reasonable proportioning, siloxane chains with different chain lengths will have good compatibility with other components, forming an excellent synergistic effect, adjusting the release rate and quantity of gases during the combustion of the cable, thereby improving the flame retardancy of the materials, optimizing the pyrolysis process, and improving the fire resistance of the materials.

[0012] As a further technical solution, the mass ratio of the chloroprene rubber to the diphenylphosphoramide is 16-25:1.

[0013] As a further technical solution, the mass ratio of the chloroprene rubber to the diphenylphosphoramide is 20:1.

[0014] As a further technical solution, the cross-linking agent includes one or two of triallyl isocyanurate and trimethylolpropane trimethacrylate.

[0015] As a further technical solution, the antioxidant includes one or two of antioxidant 1035 and antioxidant 264.

[0016] The present invention also provides a preparation method of a highly flame-retardant cable, comprising the following steps: S1. Mix the raw materials of the protective layer evenly and extrude to obtain the protective layer; S2. Wrap the insulating layer and the protective layer around the conductor in sequence to obtain the cable.

[0017] The working principle and beneficial effects of the present invention are as follows: In the present invention, a siloxane compound is added as a flame retardant assistant. The silicon-oxygen bond in the silicon-oxygen chain has high thermal stability, can maintain chemical stability in a high-temperature environment, reduce the thermal degradation of materials, form a carbonized layer at high temperature, effectively isolate oxygen, reduce the flame propagation rate, and improve the flame retardancy of the cable. Diphenylphosphoramide is also added to the cable. This substance can release reactive gases such as phosphoric acid and water vapor at high temperature. These gases help to form a protective carbonized layer, improve the flame retardancy of the cable, and can provide additional thermal stability during pyrolysis, slowing down the thermal degradation of materials. This makes the cable safer in a high-temperature environment, reducing the risk of failure. The carbon atoms of the conjugated double bonds in chloroprene rubber can also form π-π stacking with the benzene ring of diphenylphosphoramide, enhancing the binding force between the two and the overall performance of the material, thereby improving the flame retardancy and heat resistance of the cable. Detailed implementation mode

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0019] In the following examples and comparative examples: Chloroprene rubber: model CR244A, manufacturer Boruida New Materials Co., Ltd.; Ethylene-vinyl acetate copolymer: density 0.94 g / cm 3 , manufacturer Dongguan Jiagui Plastic Co., Ltd.

[0020] Example 1 S1. Weigh 100 parts of chloroprene rubber, 5 parts of ethylene-vinyl acetate copolymer, and 10 parts of alumina, and stir for 10 min to obtain a mixture; S2. Mix 5 parts of ethyltrimethoxysilane, 5 parts of octadecyltrimethoxysilane, 7 parts of diphenylphosphoramide, 0.1 part of triallyl isocyanurate, 0.3 part of antioxidant 1035 with the mixture, stir at 110 °C for 30 min, and co-extrude and pelletize through a twin-screw extruder, then send it into an extrusion molding machine for molding, sizing, traction, and cutting to obtain a protective layer; S3. Wrap the insulating layer and the protective layer around the conductor in sequence to obtain a cable.

[0021] Example 2 S1. Weigh 100 parts of chloroprene rubber, 10 parts of ethylene-vinyl acetate copolymer, and 15 parts of alumina, and stir for 15 min to obtain a mixture; S2. Mix 5.5 parts of ethyltrimethoxysilane, 5.5 parts of octadecyltrimethoxysilane, 7 parts of diphenylphosphoramide, 0.3 parts of triallyl isocyanurate, 0.5 parts of antioxidant 1035 with the mixture, stir at 120 °C for 25 min, blend and extrude through a twin-screw extruder, pelletize, and then feed it into an extrusion molding machine for molding, sizing, drawing, and cutting to obtain a protective layer; S3. Wrap the insulating layer and the protective layer around the conductor in sequence to obtain a cable.

[0022] Example 3 S1. Weigh 100 parts of chloroprene rubber, 15 parts of ethylene-vinyl acetate copolymer, and 18 parts of alumina, stir for 20 min to obtain a mixture; S2. Mix 6 parts of ethyltrimethoxysilane, 6 parts of octadecyltrimethoxysilane, 7 parts of diphenylphosphoramide, 0.5 parts of trimethylolpropane trimethacrylate, 0.6 parts of antioxidant 264 with the mixture, stir at 130 °C for 20 min, blend and extrude through a twin-screw extruder, pelletize, and then feed it into an extrusion molding machine for molding, sizing, drawing, and cutting to obtain a protective layer; S3. Wrap the insulating layer and the protective layer around the conductor in sequence to obtain a cable.

[0023] Example 4 Compared with Example 3, the difference in Example 4 is that 6 parts of ethyltrimethoxysilane and 6 parts of octadecyltrimethoxysilane are replaced with 12 parts of ethyltrimethoxysilane.

[0024] Example 5 Compared with Example 3, the difference in Example 5 is that 6 parts of ethyltrimethoxysilane and 6 parts of octadecyltrimethoxysilane are replaced with 12 parts of octadecyltrimethoxysilane.

[0025] Example 6 Compared with Example 3, the difference in Example 6 is that 6 parts of ethyltrimethoxysilane and 6 parts of octadecyltrimethoxysilane are replaced with 9 parts of ethyltrimethoxysilane and 3 parts of octadecyltrimethoxysilane.

[0026] Example 7 Compared with Example 3, the difference in Example 7 is that 6 parts of ethyltrimethoxysilane and 6 parts of octadecyltrimethoxysilane are replaced with 9.6 parts of ethyltrimethoxysilane and 2.4 parts of octadecyltrimethoxysilane.

[0027] Example 8 Compared with Example 3, the difference in Example 8 is that 6 parts of ethyltrimethoxysilane and 6 parts of octadecyltrimethoxysilane are replaced with 10 parts of ethyltrimethoxysilane and 2 parts of octadecyltrimethoxysilane.

[0028] Example 9 Compared with Example 3, Example 9 is different in that 6 parts of ethyltrimethoxysilane and 6 parts of octadecyltrimethoxysilane are replaced by 11 parts of ethyltrimethoxysilane and 1 part of octadecyltrimethoxysilane.

[0029] Example 10 Compared with Example 7, Example 10 is different in that 7 parts of diphenylphosphoramide are replaced by 6.25 parts of diphenylphosphoramide.

[0030] Example 11 Compared with Example 7, Example 11 is different in that 7 parts of diphenylphosphoramide are replaced by 5 parts of diphenylphosphoramide.

[0031] Example 12 Compared with Example 7, Example 12 is different in that 7 parts of diphenylphosphoramide are replaced by 4 parts of diphenylphosphoramide.

[0032] Example 13 Compared with Example 7, Example 13 is different in that 7 parts of diphenylphosphoramide are replaced by 3 parts of diphenylphosphoramide.

[0033] Comparative Example 1 Compared with Example 3, Comparative Example 1 is different in that ethyltrimethoxysilane and octadecyltrimethoxysilane are not added.

[0034] A highly flame-retardant cable prepared in Examples 1 to 13 and Comparative Example 1 was tested according to the following method: 1. Oxygen index: The oxygen index of the sample was tested according to the test method specified in GB / T 2406.2-2009 Plastics - Determination of burning behavior by the oxygen index method - Part 2: Ambient temperature test.

[0035] 2. Elongation at break: The elongation at break of the sample was tested according to the test method specified in GB / T 2951.11-2008 General test methods for insulating and sheathing materials of cables and optical cables - Part 11: General test methods - Measurement of thickness and overall dimensions - Mechanical properties tests.

[0036] 3. Elongation at break after aging: According to the test method specified in GB / T 2951.11-2008 "General test methods for insulating and sheathing materials of cables and optical cables - Part 11: General test methods - Measurement of thickness and external dimensions - Mechanical property tests", the cable is placed in an oven at 120 °C for 168 h, and then the elongation at break is measured, and the change rate of elongation at break is calculated. The calculation formula is: Change rate of elongation at break = (Elongation at break after treatment / Elongation at break before test - 1) × 100%.

[0037] The test results are shown in the following table: Table 1 Performance test results of the high flame-retardant cables prepared in Examples 1 to 13 and Comparative Example 1

[0038] Compared with Comparative Example 1, ethyltrimethoxysilane was added in Example 4, and octadecyltrimethoxysilane was added in Example 5. As a result, the oxygen index and elongation at break of Examples 4 and 5 were both greater than those of Comparative Example 1, and the change rate of elongation at break after aging was less than that of Comparative Example 1, indicating that the addition of siloxane compounds can effectively improve the heat resistance and flame retardancy of the cable.

[0039] Compared with Examples 4 and 5, ethyltrimethoxysilane and octadecyltrimethoxysilane were added simultaneously in Example 3. As a result, the oxygen index and elongation at break of Example 3 were both greater than those of Examples 4 and 5, and the change rate of elongation at break after aging was less than that of Examples 4 and 5, indicating that ethyltrimethoxysilane and octadecyltrimethoxysilane play a synergistic role and can further improve the heat resistance and flame retardancy of the cable.

[0040] Compared with Example 3, different mass ratios of ethyltrimethoxysilane and octadecyltrimethoxysilane were added in Examples 6 to 9. As a result, the oxygen index and elongation at break of Examples 6 to 7 were both greater than those of Examples 3 and 9, and the change rate of elongation at break after aging was less than that of Examples 3 and 9, indicating that when the mass ratio of ethyltrimethoxysilane to octadecyltrimethoxysilane is 3 - 5:1, and the preferred ratio is 4:1, the heat resistance and flame retardancy of the cable are better.

[0041] Compared with Example 7, different masses of diphenylphosphoramide were added in Examples 10 to 13. As a result, the oxygen index and elongation at break of Examples 10 to 12 were both greater than those of Examples 7 and 13, and the change rate of elongation at break after aging was less than that of Examples 7 and 13, indicating that when the mass ratio of chloroprene rubber to diphenylphosphoramide is 16 - 25:1, and the preferred ratio is 20:1, the heat resistance and flame retardancy of the obtained cable are the best.

[0042] The above are only the 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 shall be included within the protection scope of the present invention.

Claims

1. A highly flame-retardant cable, characterized in that: The invention is composed of three layers, which are a conductor, an insulating layer and a protective layer from the inside to the outside. The protective layer comprises the following component raw materials in parts by weight: 100 parts of chloroprene rubber, 5-15 parts of ethylene-vinyl acetate copolymer, 10-12 parts of flame retardant additive, 10-18 parts of aluminum oxide, 2-8 parts of diphenyl phosphoramide, 0.1-0.5 parts of cross-linking agent and 0.3-0.6 parts of antioxidant. The flame retardant additive is a siloxane compound.

2. A highly flame-retardant cable according to claim 1, characterized in that: The material of the conductor is copper.

3. A highly flame-retardant cable according to claim 1, characterized in that: The insulating layer is an ethylene propylene rubber insulating layer.

4. A highly flame-retardant cable according to claim 1, characterized in that: The flame retardant auxiliary agent is composed of siloxane compounds with different carbon chain lengths.

5. A highly flame-retardant cable according to claim 1, characterized in that: The siloxane compound consists of ethyltrimethoxysilane and octadecyltrimethoxysilane.

6. A highly flame-retardant cable according to claim 5, characterized in that: The mass ratio of the ethyltrimethoxysilane to octadecyltrimethoxysilane is 3-5:

1.

7. A highly flame-retardant cable according to claim 1, characterized in that: The mass ratio of the chloroprene rubber to diphenylphosphoramide is 16-25:

1.

8. A highly flame-retardant cable according to claim 1, characterized in that: The crosslinking agent includes one or both of triallyl isocyanurate and trimethylolpropane trimethacrylate.

9. A highly flame-retardant cable according to claim 1, characterized in that: The antioxidant includes one or both of antioxidant 1035 and antioxidant 264.

10. A method for preparing a highly flame-retardant cable according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, mixing the raw materials for the protective layer uniformly, and extruding to obtain a protective layer; S2. Wrap the insulating layer and the protective layer around the conductor in sequence to obtain a cable.

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