Flame-retardant cable and preparation method thereof

Abstract

The invention relates to the technical field of cables, and provides a flame-retardant cable and a preparation method thereof. The flame-retardant cable comprises a conductor, an insulating layer and a sheath layer, the insulating layer and the sheath layer are sequentially extruded outside the conductor, the sheath layer is prepared from, by weight, 50-60 parts of polyethylene, 10-20 parts of polyphenylene sulfide, 20-25 parts of ethylene-vinyl acetate copolymer, 15-20 parts of filler, 0.5-1.5 parts of lubricant, 15-20 parts of flame retardant and 1-1.5 parts of anti-aging agent, and the polyphenylene sulfide is composed of first polyphenylene sulfide and second polyphenylene sulfide. The first polyphenylene sulfide and the second polyphenylene sulfide have different reinforcing phase substances. According to the technical scheme, the problem of low flame retardant property of the cable in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a flame retardant cable and a preparation method thereof. Background Art

[0002] In modern society, power and information transmission are everywhere. As an important carrier, the safety of cables is of vital importance. Flame-retardant cables are cables that, under specified test conditions, when the sample is burned, after the test fire source is removed, the flame spreads only within a limited range, and the residual flame or residual burning can extinguish itself within a limited time. Its fundamental characteristic is that although it may be burned and unable to operate in the event of a fire, it can prevent the fire from spreading.

[0003] Flame-retardant cables are widely used in many key areas. In the field of construction, whether it is a residential residence, a crowded shopping mall, office building, or a public building such as a school or hospital, flame-retardant cables are used in power supply, communication, and security systems to ensure the safety of power and signal transmission in the building and reduce fire hazards. In the field of transportation, the power supply system, communication system, and navigation system of various means of transportation, such as cars, trains, airplanes, and ships, are inseparable from flame-retardant cables. They escort the stable operation of the means of transportation and the safety of passengers. Ships are sailing on the sea in a relatively closed space. Once a fire occurs, the consequences are disastrous. The wide application of flame-retardant cables in the power supply, communication, and navigation systems of ships can effectively reduce the possibility of fire and ensure the safety of ships and crew members.

[0004] At present, flame-retardant cables are increasingly used in the market, but there are still some problems in actual use. The flame-retardant effect of some flame-retardant cables is not good, and it is difficult to effectively contain the spread of the fire when encountering a fire. Once the flame-retardant cable fails to play its due flame-retardant role, the fire will spread rapidly along the cable, expanding the scope of the fire in a short period of time, causing damage to the building structure and increasing the risk of collapse. At the same time, the large amount of thick smoke produced by combustion will not only hinder people's vision and make evacuation difficult, but may also cause people to inhale harmful gases, causing poisoning, suffocation and other dangerous situations. Therefore, it is very necessary to develop a cable with high flame retardant properties. Summary of the invention

[0005] The invention provides a flame retardant cable and a preparation method thereof, which solves the problem of low flame retardant performance of the cable in the related art.

[0006] The technical solution of the present invention is as follows: The present invention proposes a flame-retardant cable, comprising a conductor and an insulating layer and a sheath layer extruded sequentially outside the conductor, the sheath layer comprising the following component raw materials in parts by weight: 50-60 parts of polyethylene, 10-20 parts of polyphenylene sulfide, 20-25 parts of ethylene-vinyl acetate copolymer, 15-20 parts of filler, 0.5-1.5 parts of lubricant, 15-20 parts of flame retardant, and 1-1.5 parts of antioxidant, the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide, and the reinforcing phase materials of the first polyphenylene sulfide and the second polyphenylene sulfide are different.

[0007] As a further technical solution, the conductor is made of copper.

[0008] As a further technical solution, the material of the insulating layer is cross-linked polyethylene.

[0009] As a further technical solution, the reinforcing phase material of the first polyphenylene sulfide is glass fiber, the reinforcing phase material of the second polyphenylene sulfide is glass fiber and calcium carbonate, the reinforcing phase material content of the first polyphenylene sulfide and the second polyphenylene sulfide is each independently 50wt%, and the mass ratio of the first polyphenylene sulfide to the second polyphenylene sulfide is 2:4~5.

[0010] In the present invention, the glass fiber has high strength, high modulus and good heat resistance, and can play a role in enhancing the mechanical properties of the material in both polyphenylene sulfides. At the same time, it forms a physical barrier structure during combustion, slows down heat transfer and oxygen diffusion, and lays the foundation for flame retardant properties. The calcium carbonate in the second polyphenylene sulfide has a low cost. While providing a certain rigidity, it decomposes and absorbs heat at high temperature, reduces the material temperature, and the decomposition produces carbon dioxide and other gases that dilute the concentration of combustible gases, which assists in flame retardancy. When two polyphenylene sulfides with different reinforcing phase materials are used simultaneously in a specific ratio, a synergistic effect is exerted, combustion is suppressed from multiple dimensions, heat transfer and material transmission paths inside the material are optimized, and the flame retardant properties of the cable are improved.

[0011] As a further technical solution, the lubricant includes one or both of stearic acid and calcium stearate.

[0012] In the present invention, adding a lubricant can reduce the internal friction of the polymer melt, making it easier for the polymer molecular chains to slide relative to each other, making the extrusion process of the cable sheath material smoother, and the lubricant also helps to make the surface of the cable sheath smoother and flatter, thereby improving the surface quality of the cable.

[0013] As a further technical solution, the flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

[0014] In the present invention, an inorganic flame retardant is added on the basis of the flame retardancy of polyphenylene sulfide itself. When the flame retardant and polyphenylene sulfide act together on the cable sheath layer, the carbon layer formed by the polyphenylene sulfide provides an attachment and support structure for the decomposition products of the flame retardant, which helps the flame retardant to better play the role of absorbing heat, diluting gas, and blocking heat and oxygen; and the presence of the flame retardant further promotes the carbonization reaction of polyphenylene sulfide during the combustion process. The two work together to improve the flame retardant performance of the cable.

[0015] As a further technical solution, the antioxidant includes one or both of antioxidant 4010NA and antioxidant 4020.

[0016] In the present invention, an antioxidant is added to delay the aging process of the cable and increase the service life of the cable.

[0017] As a further technical solution, the filler includes one or more of calcium carbonate, mica powder, and wollastonite.

[0018] In the present invention, the addition of fillers can effectively enhance the hardness and rigidity of the cable sheath. The fillers are distributed in the polymer matrix and play a supporting role, so that the cable sheath can better resist external force extrusion and is not easily deformed, so that it can maintain a stable shape in complex installation and use environments.

[0019] As a further technical solution, the filler is a chlorophenylamide compound composite filler, and the chlorophenylamide compound in the chlorophenylamide compound composite filler includes one or two of 2-chlorobenzamide and 3,5-dichlorobenzamide.

[0020] In the present invention, the filler is compounded with a chlorophenylamide compound to enhance the intermolecular force between the filler and the polymer matrix, and the filler and the matrix are tightly combined together to form a whole. During the stress process, the stress can be transmitted more evenly, avoiding material damage caused by local stress concentration, thereby enhancing the mechanical strength of the cable.

[0021] As a further technical solution, the raw materials of the chlorophenylamide compound composite filler include a chlorophenylamide compound and a filler in a mass ratio of 1 to 2:15.

[0022] As a further technical solution, the preparation method of the chlorophenylamide compound composite filler comprises the following steps: dispersing the chlorophenylamide compound in a solvent, adding a filler and mixing, and drying to obtain the chlorophenylamide compound composite filler.

[0023] As a further technical solution, the solvent is acetone and the mixing time is 2 hours.

[0024] As a further technical solution, the mass ratio of the solvent to the filler is 1.5~3:1.

[0025] The present invention also provides a method for preparing a flame retardant cable, which is used to prepare the flame retardant cable, comprising the following steps: S1. After extruding an insulating layer outside the conductor, a semi-finished cable is obtained; S2. The raw materials of the sheath layer are mixed and extruded outside the semi-finished cable to obtain a flame-retardant cable.

[0026] The working principle and beneficial effects of the present invention are: In the present invention, polyethylene, polyphenylene sulfide, and ethylene-vinyl acetate copolymer are used as matrix materials, and fillers, lubricants, flame retardants, and antioxidants are added to prepare a cable sheath layer. Polyethylene has good flexibility and processing performance, so that the cable sheath is easy to process and shape. Ethylene-vinyl acetate copolymer has high elasticity and good environmental stress cracking resistance, which can enhance the elasticity and flexibility of the cable sheath. Polyphenylene sulfide has high strength and rigidity, which can increase the hardness and deformation resistance of the cable sheath, improve the mechanical stability of the cable in a complex environment, and ensure that the cable is long. The cable will not be damaged by external forces during its use. The filler enhances the mechanical properties of the cable. The lubricant improves the processing performance of the cable and improves the surface quality of the cable. The flame retardant enhances the flame retardant properties of the cable. The antioxidant delays the aging process of the cable. By reasonably matching the dosage of each component, a cable sheath layer is obtained, and a flame-retardant cable is obtained after extrusion. The polyphenylene sulfide in the present invention is composed of a first polyphenylene sulfide and a second polyphenylene sulfide with different reinforcing phase materials. Different reinforcing phase materials exert their own unique flame retardant effects, forming a diversified flame retardant mechanism, producing a synergistic effect, and improving the flame retardant properties of the cable. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples: Insulation layer: cross-linked polyethylene insulation layer; First polyphenylene sulfide: the reinforcement phase material is glass fiber, the reinforcement phase material content is 50wt%, and the model is PPSLGF50; Second polyphenylene sulfide: the reinforcement phase material is glass fiber and calcium carbonate, the reinforcement phase material content is 50wt%, and the model is C-220SC; Polyethylene: Model DFDA-7047; Ethylene-vinyl acetate copolymer: model 18F20; Calcium carbonate: average particle size is 325 mesh; Wollastonite: average particle size is 400 mesh; Mica powder: average particle size is 325 mesh.

[0029] Example 1 A method for preparing a flame retardant cable comprises the following steps: S1. After extruding an insulating layer outside the copper conductor, a semi-finished cable is obtained; S2. Weigh 50 parts of polyethylene, 10 parts of polyphenylene sulfide, 20 parts of ethylene-vinyl acetate copolymer, 15 parts of calcium carbonate, 0.5 parts of stearic acid, 15 parts of magnesium hydroxide, and 1 part of antioxidant 4010NA, mix them, and extrude them onto the semi-finished cable to obtain a flame-retardant cable; the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 1:2.

[0030] Example 2 A method for preparing a flame retardant cable comprises the following steps: S1. After extruding an insulating layer outside the copper conductor, a semi-finished cable is obtained; S2. Weigh 55 parts of polyethylene, 15 parts of polyphenylene sulfide, 22 parts of ethylene-vinyl acetate copolymer, 18 parts of mica powder, 1 part of stearic acid, 18 parts of magnesium hydroxide, and 1.2 parts of antioxidant 4020, mix them, and extrude them onto the semi-finished cable to obtain a flame-retardant cable; the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 1:2.

[0031] Example 3 A method for preparing a flame retardant cable comprises the following steps: S1. After extruding an insulating layer outside the copper conductor, a semi-finished cable is obtained; S2. Weigh 60 parts of polyethylene, 20 parts of polyphenylene sulfide, 25 parts of ethylene-vinyl acetate copolymer, 20 parts of wollastonite, 1.5 parts of calcium stearate, 20 parts of aluminum hydroxide, and 1.5 parts of antioxidant 4020, mix them, and extrude them onto the semi-finished cable to obtain a flame-retardant cable; the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 1:2.

[0032] Example 4 Compared with Example 1, Example 4 is different in that the polyphenylene sulfide consists of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 2:5.

[0033] Example 5 The preparation method of chlorophenylamide compound composite calcium carbonate comprises the following steps: dispersing 1 part of 2-chlorobenzamide in 30 parts of acetone, adding 15 parts of calcium carbonate, stirring at 400 rpm for 2 hours, and then drying to obtain chlorophenylamide compound composite calcium carbonate; A method for preparing a flame retardant cable comprises the following steps: S1. After extruding an insulating layer outside the copper conductor, a semi-finished cable is obtained; S2. Weigh 50 parts of polyethylene, 10 parts of polyphenylene sulfide, 20 parts of ethylene-vinyl acetate copolymer, 15 parts of chlorophenylamide compound calcium carbonate, 0.5 parts of stearic acid, 15 parts of magnesium hydroxide, and 1 part of antioxidant 4010NA, mix them, and extrude them on the outside of the semi-finished cable to obtain a flame-retardant cable; the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 1:2.

[0034] Example 6 Compared with Example 5, the difference of Example 6 is that in the preparation process of the chlorophenylamide compound composite calcium carbonate, the added amount of 2-chlorobenzamide is 2 parts.

[0035] Example 7 Compared with Example 5, Example 7 is different in that 2-chlorobenzamide is replaced by an equal amount of 3,5-dichlorobenzamide.

[0036] Example 8 A method for preparing a flame retardant cable comprises the following steps: S1. After extruding an insulating layer outside the copper conductor, a semi-finished cable is obtained; S2. Weigh 50 parts of polyethylene, 10 parts of polyphenylene sulfide, 20 parts of ethylene-vinyl acetate copolymer, 15 parts of calcium carbonate, 1 part of 2-chlorobenzamide, 0.5 parts of stearic acid, 15 parts of magnesium hydroxide, and 1 part of antioxidant 4010NA, mix them, and extrude them onto the semi-finished cable to obtain a flame-retardant cable; the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 1:2.

[0037] Comparative Example 1 Compared with Example 1, the difference in Comparative Example 1 is that the polyphenylene sulfide is the first polyphenylene sulfide.

[0038] Comparative Example 2 Compared with Example 1, the difference in Comparative Example 2 is that the polyphenylene sulfide is a second polyphenylene sulfide.

[0039] Experimental Example 1 Take the sheath layer of the flame-retardant cable prepared in Examples 1 to 4 and Comparative Examples 1 to 2, and perform an oxygen index test according to the test method specified in GB / T 2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method Part 2: Room Temperature Experiment"; wherein the sample shape is a Type IV sample, the sample size is 100 mm×6 mm×3 mm, and the ignition method is Method A.

[0040] The test results are shown in Table 1: Table 1 Performance test results of flame retardant cables prepared in Examples 1 to 4 and Comparative Examples 1 to 2

[0041] Compared with Comparative Examples 1 and 2, the oxygen index of Examples 1 to 4 is greater than that of Comparative Examples 1 and 2, indicating that the first polyphenylene sulfide and the second polyphenylene sulfide play a synergistic role and can improve the flame retardant properties of the cable.

[0042] Experimental Example 2 The flame-retardant cables prepared in Example 1 and Examples 5 to 8 were tested for tensile strength according to the test method specified in GB / T 2951.11-2008 "General test methods for insulation and sheath materials of electric and optical cables Part 11: General test methods - Thickness and dimensional measurement - Mechanical properties test". Sample preparation: The sheath was cut along the axial direction of the cable, and a narrow strip was cut to make a small dumbbell specimen with a thickness of 2.0 mm, which was the sample to be tested.

[0043] The test results are shown in Table 2: Table 2 Performance test results of flame retardant cables prepared in Example 1 and Examples 5 to 8

[0044] Compared with Example 1 and Example 8, the tensile strength of Examples 5 to 7 is higher than that of Example 1 and Example 8, indicating that the addition of the chlorophenylamide compound composite filler can improve the mechanical strength of the cable.

[0045] The above are only 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 in the protection scope of the present invention.

Claims

1. A flame retardant cable, characterized in that: The invention comprises a conductor and an insulating layer and a sheath layer which are sequentially extruded outside the conductor, wherein the sheath layer comprises the following component raw materials in parts by weight: 50-60 parts of polyethylene, 10-20 parts of polyphenylene sulfide, 20-25 parts of ethylene-vinyl acetate copolymer, 15-20 parts of filler, 0.5-1.5 parts of lubricant, 15-20 parts of flame retardant and 1-1.5 parts of antioxidant. The polyphenylene sulfide consists of a first polyphenylene sulfide and a second polyphenylene sulfide, and the reinforcing phase materials of the first polyphenylene sulfide and the second polyphenylene sulfide are different.

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

3. A flame-retardant cable according to claim 1, characterized in that: The material of the insulating layer is cross-linked polyethylene.

4. A flame-retardant cable according to claim 1, characterized in that: The reinforcing phase material of the first polyphenylene sulfide is glass fiber, and the reinforcing phase material of the second polyphenylene sulfide is glass fiber and calcium carbonate. The reinforcing phase material content of the first polyphenylene sulfide and the second polyphenylene sulfide is each independently 50wt%, and the mass ratio of the first polyphenylene sulfide to the second polyphenylene sulfide is 2:4~5.

5. A flame-retardant cable according to claim 1, characterized in that: Also includes at least one of the following technical features: The lubricant includes one or both of stearic acid and calcium stearate; The flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

6. A flame-retardant cable according to claim 1, characterized in that: The antioxidant includes one or both of antioxidant 4010NA and antioxidant 4020.

7. A flame-retardant cable according to claim 1, characterized in that: The filler includes one or more of calcium carbonate, mica powder and wollastonite.

8. The flame-retardant cable according to claim 1, characterized in that: The filler is a chlorophenylamide compound composite filler, and the chlorophenylamide compound in the chlorophenylamide compound composite filler includes one or two of 2-chlorobenzamide and 3,5-dichlorobenzamide.

9. A flame-retardant cable according to claim 8, characterized in that: The raw materials of the chlorophenylamide compound composite filler include a chlorophenylamide compound and a filler in a mass ratio of 1 to 2:

15.

10. A method for preparing a flame-retardant cable, used for preparing a flame-retardant cable as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1. After extruding an insulating layer outside the conductor, a semi-finished cable is obtained; S2. The raw materials of the sheath layer are mixed and extruded outside the semi-finished cable to obtain a flame-retardant cable.

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