Flame-retardant cable and method for producing the same

Abstract

This invention relates to the field of cable technology and proposes a flame-retardant cable and its preparation method. A flame-retardant cable includes a conductor and an insulation layer and a sheath layer sequentially extruded around the conductor. The sheath layer comprises the following raw materials in parts by weight: 50-60 parts polyethylene, 10-20 parts polyphenylene sulfide (PPS), 20-25 parts ethylene-vinyl acetate copolymer, 15-20 parts filler, 0.5-1.5 parts lubricant, 15-20 parts flame retardant, and 1-1.5 parts antioxidant. The PPS is composed of a first PPS and a second PPS, with different reinforcing phases in the first and second PPS. This technical solution solves the problem of low flame-retardant performance in related technologies.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a flame-retardant cable and its preparation method. Background Technology

[0002] In modern society, electricity and information transmission are ubiquitous, and cables, as vital carriers, are of paramount importance for their safety. Flame-retardant cables, under specified test conditions, are cables in which, after the test flame source is removed, the flame spreads only within a limited area, and any remaining flames or embers self-extinguish within a limited time. Their fundamental characteristic is that although they may be damaged and rendered inoperable in a fire, they can prevent the spread of fire.

[0003] Flame-retardant cables are widely used in many key fields. In the construction industry, whether in residential buildings, densely populated shopping malls, office buildings, or public buildings such as schools and hospitals, flame-retardant cables are used in power supply, communication, and security systems to ensure the safety of power and signal transmission within buildings and reduce fire hazards. In the transportation industry, various vehicles such as cars, trains, airplanes, and ships rely on flame-retardant cables for their power supply, communication, and navigation systems. They safeguard the stable operation of vehicles and the safety of passengers. Ships sailing at sea have relatively enclosed spaces, and the consequences of a fire would be unimaginable. The widespread use of flame-retardant cables in the power supply, communication, and navigation systems of ships can effectively reduce the possibility of fires and ensure the safety of ships and crew.

[0004] Currently, flame-retardant cables are increasingly widely used in the market, but some problems still exist in practical applications. Some flame-retardant cables have poor flame-retardant properties, making it difficult to effectively contain the spread of fire in the event of a fire. Once the flame-retardant cable fails to perform its intended function, the fire will spread rapidly along the cable, expanding the fire area in a short time, causing structural damage to buildings and increasing the risk of collapse. Simultaneously, the large amount of dense smoke produced by combustion not only obstructs visibility, making evacuation extremely difficult, but may also lead to the inhalation of harmful gases, causing poisoning, suffocation, and other dangerous situations. Therefore, it is essential to develop a cable with high flame-retardant properties. Summary of the Invention

[0005] This invention proposes a flame-retardant cable and its preparation method, which solves the problem of low flame-retardant performance of cables in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes a flame-retardant cable, comprising a conductor and an insulation layer and a sheath layer extruded sequentially around the conductor. The sheath layer comprises the following 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, wherein 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, and the reinforcing phase material of the second polyphenylene sulfide is glass fiber and calcium carbonate. The content of the reinforcing phase material of the first polyphenylene sulfide and the second polyphenylene sulfide is 50 wt% each, and the mass ratio of the first polyphenylene sulfide and the second polyphenylene sulfide is 2:4~5.

[0010] In this invention, glass fiber, possessing high strength, high modulus, and good heat resistance, enhances the mechanical properties of both types of polyphenylene sulfide (PPS). Simultaneously, it forms a physical barrier structure during combustion, slowing heat transfer and oxygen diffusion, thus laying the foundation for flame retardant performance. The calcium carbonate in the second PPS is low-cost and, while providing a certain degree of rigidity, decomposes and absorbs heat at high temperatures, lowering the material temperature. The carbon dioxide and other gases produced during decomposition dilute the concentration of combustible gases, further aiding in flame retardancy. When the two PPS with different reinforcing phases are used simultaneously in a specific ratio, they exert a synergistic effect, inhibiting combustion from multiple dimensions, optimizing the internal heat transfer and mass transport paths of the material, and improving the flame retardant performance of the cable.

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

[0012] In this invention, the addition of 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. The lubricant also helps to make the surface of the cable sheath smoother and flatter, 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 this invention, an inorganic flame retardant is added to the flame-retardant properties of polyphenylene sulfide (PPS). When the flame retardant and PPS work together on the cable sheath, the char layer formed by PPS provides an attachment and support structure for the decomposition products of the flame retardant, which helps the flame retardant to better perform its functions of heat absorption, gas dilution, and heat and oxygen barrier. The presence of the flame retardant further promotes the char formation reaction of PPS during combustion. The two work synergistically 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 this invention, an anti-aging agent is added to slow down the aging process of the cable and improve its service life.

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

[0018] In this invention, the addition of filler can effectively enhance the hardness and rigidity of the cable sheath. The filler is distributed in the polymer matrix and plays a supporting role, enabling the cable sheath to better resist external pressure and not easily deform, so as to maintain its shape stability in complex installation and use environments.

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

[0020] In this invention, chlorophenylamide compounds are used to composite the filler, which enhances the intermolecular forces between the filler and the polymer matrix, tightly bonding the filler and the matrix 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 for the chlorophenylamide compound composite filler include chlorophenylamide compounds and fillers in a mass ratio of 1~2:15.

[0022] As a further technical solution, the preparation method of the chlorophenylamide compound composite filler includes the following steps: dispersing the chlorophenylamide compound in a solvent, adding 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] This invention also proposes a method for preparing a flame-retardant cable, comprising the following steps:

[0026] S1. After extruding an insulation layer around the conductor, a semi-finished cable is obtained;

[0027] S2. The raw materials for the sheath layer are mixed and extruded onto the outside of the cable semi-finished product to obtain a flame-retardant cable.

[0028] The working principle and beneficial effects of this invention are as follows:

[0029] In this invention, polyethylene, polyphenylene sulfide, and ethylene-vinyl acetate copolymer are used as matrix materials, and fillers, lubricants, flame retardants, and anti-aging agents are added to prepare a cable sheath layer. Polyethylene has good flexibility and processing performance, making the cable sheath easy to process and shape. Ethylene-vinyl acetate copolymer has high elasticity and good resistance to environmental stress cracking, 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 complex environments, and ensure the cable's long-term stability. During its service life, the cable will not be damaged by external forces. The filler enhances the mechanical properties of the cable, the lubricant improves the processing performance of the cable and enhances the surface quality of the cable, the flame retardant enhances the flame retardant performance of the cable, and the anti-aging agent slows down the aging process of the cable. By reasonably matching the dosage of each component, the cable sheath layer is obtained, and after extrusion, the flame retardant cable is obtained. In this invention, the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide with different reinforcing phase materials. Different reinforcing phase materials play their own unique flame retardant role, forming a diversified flame retardant mechanism, producing a synergistic effect, and improving the flame retardant performance of the cable. 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:

[0032] Insulation layer: Cross-linked polyethylene insulation layer;

[0033] First polyphenylene sulfide: The reinforcing phase material is glass fiber, the content of the reinforcing phase material is 50wt%, and the model is PPSLGF50;

[0034] Second polyphenylene sulfide: The reinforcing phase material is glass fiber and calcium carbonate, the content of the reinforcing phase material is 50wt%, and the model is C-220SC.

[0035] Polyethylene: Model number DFDA-7047;

[0036] Ethylene-vinyl acetate copolymer: Model number 18F20;

[0037] Calcium carbonate: average particle size is 325 mesh;

[0038] Wollastonite: average particle size is 400 mesh;

[0039] Mica powder: average particle size is 325 mesh.

[0040] Example 1

[0041] A method for preparing a flame-retardant cable includes the following steps:

[0042] S1. After extruding an insulation layer over the copper conductor, a semi-finished cable is obtained;

[0043] 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. After mixing, extrude the mixture onto the outside of the cable semi-finished product 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.

[0044] Example 2

[0045] A method for preparing a flame-retardant cable includes the following steps:

[0046] S1. After extruding an insulation layer over the copper conductor, a semi-finished cable is obtained;

[0047] 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. After mixing, extrude the mixture onto the outside of the cable semi-finished product to obtain a flame-retardant cable. The polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide with a mass ratio of 1:2.

[0048] Example 3

[0049] A method for preparing a flame-retardant cable includes the following steps:

[0050] S1. After extruding an insulation layer over the copper conductor, a semi-finished cable is obtained;

[0051] 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. After mixing, extrude the mixture onto the outside of the cable semi-finished product to obtain a flame-retardant cable. The polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide with a mass ratio of 1:2.

[0052] Example 4

[0053] The difference between Example 4 and Example 1 is that the polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide in a mass ratio of 2:5.

[0054] Example 5

[0055] The preparation method of chlorophenylamide compound composite calcium carbonate includes the following steps: 1 part of 2-chlorobenzamide is dispersed in 30 parts of acetone, 15 parts of calcium carbonate are added and stirred at 400 rpm for 2 hours, and then dried to obtain chlorophenylamide compound composite calcium carbonate;

[0056] A method for preparing a flame-retardant cable includes the following steps:

[0057] S1. After extruding an insulation layer over the copper conductor, a semi-finished cable is obtained;

[0058] 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. After mixing, extrude the mixture onto the cable semi-finished product to obtain a flame-retardant cable. The polyphenylene sulfide is composed of a first polyphenylene sulfide and a second polyphenylene sulfide with a mass ratio of 1:2.

[0059] Example 6

[0060] Compared with Example 5, the difference in Example 6 is that, in the preparation of the chlorophenylamide compound calcium carbonate, the amount of 2-chlorobenzamide added is 2 parts.

[0061] Example 7

[0062] The difference between Example 7 and Example 5 is that 2-chlorobenzamide is replaced with an equal amount of 3,5-dichlorobenzamide.

[0063] Example 8

[0064] A method for preparing a flame-retardant cable includes the following steps:

[0065] S1. After extruding an insulation layer over the copper conductor, a semi-finished cable is obtained;

[0066] 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. After mixing, extrude the mixture onto the outside of the cable semi-finished product 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.

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that the polyphenylene sulfide is a first polyphenylene sulfide.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 2 and Example 1 is that the polyphenylene sulfide is a second polyphenylene sulfide.

[0071] Experimental Example 1

[0072] The sheaths of the flame-retardant cables prepared in Examples 1-4 and Comparative Examples 1-2 were tested for oxygen index according to the test method specified in GB / T 2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part II: Room Temperature Test"; wherein the sample shape was a Type IV sample, the sample size was 100mm×6mm×3mm, and the ignition method was Method A.

[0073] The test results are shown in Table 1:

[0074] Table 1 Performance test results of flame-retardant cables prepared in Examples 1-4 and Comparative Examples 1-2

[0075]

[0076] 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 in improving the flame retardant performance of the cable.

[0077] Experiment Example 2

[0078] The flame-retardant cables prepared in Examples 1 and 5-8 were tested for tensile strength according to the test methods specified in GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 11: General Test Methods - Measurement of Thickness and Dimensions - Mechanical Properties Test". Specimen preparation: The sheath was cut along the cable axis, and a narrow strip was cut to make a small dumbbell specimen with a thickness of 2.0 mm, which is the test specimen.

[0079] The test results are shown in Table 2:

[0080] Table 2 Performance test results of flame-retardant cables prepared in Examples 1 and 5-8

[0081]

[0082] Compared with Examples 1 and 8, the tensile strength of Examples 5-7 is higher than that of Examples 1 and 8, indicating that the addition of chlorophenylamide compound composite filler can improve the mechanical strength of the cable.

[0083] 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 flame-retardant cable, characterized in that, The device includes a conductor and an insulating layer and a sheath layer sequentially extruded over the conductor. The sheath layer comprises the following raw materials in parts by weight: 50-60 parts polyethylene, 10-20 parts polyphenylene sulfide, 20-25 parts ethylene-vinyl acetate copolymer, 15-20 parts filler, 0.5-1.5 parts lubricant, 15-20 parts flame retardant, and 1-1.5 parts 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. The reinforcing phase of the first polyphenylene sulfide is glass fiber, and the reinforcing phase of the second polyphenylene sulfide is glass fiber and calcium carbonate. The content of the reinforcing phase of the first polyphenylene sulfide and the second polyphenylene sulfide is 50 wt% each, and the mass ratio of the first polyphenylene sulfide to the second polyphenylene sulfide is 2:4~5.

2. The flame-retardant cable according to claim 1, characterized in that, The conductor is made of copper.

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

4. A flame-retardant cable according to claim 1, characterized in that, It 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.

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

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

7. A flame-retardant cable according to claim 1, characterized in that, The packing material is a chlorophenylamide compound composite packing material, wherein the chlorophenylamide compound in the chlorophenylamide compound composite packing material includes one or two of 2-chlorobenzamide and 3,5-dichlorobenzamide.

8. A flame-retardant cable according to claim 7, characterized in that, The raw materials for the chlorophenylamide compound composite filler include chlorophenylamide compounds and fillers in a mass ratio of 1 to 2:

15.

9. A method for preparing a flame-retardant cable, used to prepare a flame-retardant cable as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. After extruding an insulation layer around the conductor, a semi-finished cable is obtained; S2. The raw materials for the sheath layer are mixed and extruded onto the outside of the cable semi-finished product to obtain a flame-retardant cable.

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