Environment-friendly fire-resistant cable and preparation method thereof

Abstract

The invention discloses an environment-friendly fire-resistant cable and a preparation method thereof, and belongs to the technical field of power cables. The cable comprises a conductor, an insulating layer, a metal shielding layer and an outer sheath layer, the insulating layer, the metal shielding layer and the outer sheath layer are sequentially arranged outside the conductor, and the outer sheath layer comprises the following raw materials in parts by weight: 75-85 parts of polyethylene, 8-12 parts of tea polyphenol flame-retardant particles, 0.5-1 part of a lubricant, 0.5-3 parts of an antioxidant and 0.8-3 parts of a peroxide cross-linking agent. The flame-retardant material is obtained by adding the tea polyphenol microcapsules and has good flame-retardant, anti-ultraviolet and antibacterial properties, and meanwhile, the preparation method has the advantages that the process is simple, and the raw materials are easy to obtain.

Description

Technical Field

[0001] The present invention relates to the field of cables, and in particular to an environmentally friendly fire-resistant cable and a preparation method thereof. Background Art

[0002] In modern society, people are increasingly dependent on fire, and the harm it causes is becoming increasingly serious. Therefore, fire safety in power transmission systems has become a focus of public attention. Conventional wires and cables release fumes containing toxic gases such as hydrogen halides, carbon monoxide, and carbon dioxide during combustion. This not only hinders rescue operations but can also cause secondary damage to life and property. Therefore, flame retardancy has become an essential consideration for cable design. With rapid economic development, wires and cables, a vital component of the national economy, are experiencing a continuous expansion in both usage and application. In recent years, demand for cables has surged in industries such as power plants, substations, metallurgy, and petrochemicals. Long-term exposure to heat, oxygen, and ultraviolet radiation can lead to aging and degradation of cables. Furthermore, prolonged exposure to damp, dark environments can easily breed bacteria on the cable surface, corroding the insulation and compromising its protective properties. Therefore, there is an urgent need for antibacterial, flame-retardant, and UV-resistant cables.

[0003] Therefore, the present invention is specially proposed to solve the above technical problems. Summary of the Invention

[0004] In view of the above technical problems existing in the prior art, the present invention provides an environmentally friendly fire-resistant cable and a preparation method thereof, so as to improve the anti-aging and anti-corrosion properties of the cable.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an environmentally friendly fire-resistant cable, comprising a conductor, and an insulating layer, a metal shielding layer, and an outer sheath layer sequentially arranged outside the conductor, characterized in that the outer sheath layer comprises the following raw materials in parts by weight: 75-85 parts of polyethylene, 8-12 parts of tea polyphenol flame retardant particles, 0.5-1 part of lubricant, 0.5-3 parts of antioxidant, and 0.8-3 parts of peroxide crosslinking agent.

[0006] Preferably, the tea polyphenols flame retardant particles are prepared by the following steps: dissolving 8 to 18 parts by weight of tea polyphenols in 8 to 18 parts by weight of water to prepare a first solution; A second solution is prepared by adding 6 to 9 parts by weight of an emulsifier to 65 to 75 parts by weight of an oily substance and fully dissolving the emulsifier. Slowly add the first solution to the second solution and emulsify at 12000 rpm for 10-20 min to prepare an emulsion; 30-70 parts by weight of the wall material, 30-70 parts by weight of water, and 1-3 parts by weight of phenyl glycidyl ether are mixed to prepare a third solution; The obtained emulsion was added to the third solution, stirred at a rotation speed of 12000 rpm for 10 to 20 minutes, and then spray-dried to obtain tea polyphenol flame-retardant particles.

[0007] Preferably, the oily substance is any one of dimethyl silicone oil, soybean oil, and corn oil.

[0008] Preferably, the emulsifier is any one of Span80, Span40, and Tween 60. Preferably, the wall material is any one of gelatin, sodium alginate, ethyl cellulose and methyl cellulose.

[0009] Preferably, the conductor adopts a round copper conductor structure of twisted copper wires.

[0010] Preferably, the insulating layer is made of cross-linked polyethylene insulating material.

[0011] Preferably, the antioxidant is one or more combinations of antioxidant 1035 and antioxidant 1010.

[0012] Preferably, the lubricant is a combination of one or more of calcium stearate, stearic acid, oxidized polyethylene wax and microcrystalline wax.

[0013] Preferably, the peroxide crosslinking agent is one or more combinations of dicumyl peroxide (DCP), benzoyl peroxide (BPO), and di-tert-butyl peroxide (DTBP).

[0014] In another aspect, the present invention further provides a method for preparing an environmentally friendly fire-resistant cable, comprising the following steps: The copper wire is drawn into a wire drawing machine, annealed, and then twisted to obtain a conductor; The insulating material is coated on the conductor by an insulating layer extruder to form an insulating layer; After the formed insulated conductor is cooled and formed, aluminum foil, copper foil or iron foil is wrapped around the surface of the cable core to form a metal shielding layer; The components of the outer sheath layer are melt-blended at 140° C. through an open mill and then extruded onto the outside of the metal shielding layer to form an outer sheath layer, thereby producing an environmentally friendly fire-resistant cable.

[0015] The beneficial effects of the present invention are: The present invention provides an environmentally friendly, fire-resistant cable. Tea polyphenols, a general term for polyphenols found in tea leaves, are a natural aromatic hydrocarbon biomass. They exhibit excellent environmental friendliness and prevent the release of harmful hydrogen halides during combustion of halogen-containing flame-retardant cables. Due to their unique benzene ring structure and pronounced phenolic properties, the tea polyphenols contained in the flame-retardant microcapsules initially transform into a semi-fluid state as temperature rises. This is accompanied by the extensive cleavage of aromatic side chains, which, during thermal decomposition, generate active free radicals that interfere with and disrupt the combustion chain reaction, thereby quenching the flame. The released inert gases, such as H2O and CO2, dilute the concentration of oxygen and combustible gases while rapidly expanding. The accumulated benzene ring structures in the solid residue raise its melting point, resulting in a fixed volume and a dense, solid black carbon layer with a porous and loose interior. Ultimately, flame retardancy is achieved.

[0016] Tea polyphenols have a benzene ring structure. The absorption peak of tea polyphenols is usually in the range of 200~400 nanometers, which can absorb ultraviolet rays. When tea polyphenols are introduced into the material, part of the ultraviolet rays can be absorbed through the ultraviolet absorption ability of tea polyphenols, further reducing the ultraviolet rays contacting the cable structure, thereby achieving a better anti-ultraviolet effect, which can effectively prevent the cable from deformation, discoloration, cracking, etc. due to the action of ultraviolet rays.

[0017] The tea polyphenols in the present invention can destroy bacterial cell membranes and have a good antibacterial effect.

[0018] The tea polyphenol flame retardant particles of the present invention have a microcapsule structure, which can effectively protect the flame retardant and ensure that the tea polyphenol is evenly dispersed and effectively released in the polymer material, thereby improving the flame retardant performance of the material. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] Example 1 An environmentally friendly fire-resistant cable comprises a conductor, and an insulating layer, a metal shielding layer and an outer sheath layer which are sequentially arranged outside the conductor.

[0021] The outer sheath layer comprises the following raw materials in parts by weight: 75 parts of polyethylene, 8 parts of tea polyphenol flame retardant particles, 0.5 parts of lubricant, 0.5 parts of antioxidant, and 0.8 parts of peroxide cross-linking agent.

[0022] The tea polyphenols flame retardant particles are prepared by the following steps: Dissolving 8 parts by weight of tea polyphenols in 8 parts by weight of water to prepare a first solution; 6 parts by weight of an emulsifier was added to 65 parts by weight of an oily substance and fully dissolved to prepare a second solution; The first solution was slowly added to the second solution, and emulsified at a speed of 12000 rpm for 10 min to prepare an emulsion; 30 parts by weight of the wall material, 30 parts by weight of water, and 1 part by weight of phenyl glycidyl ether were mixed to prepare a third solution; The obtained emulsion was added to the third solution, stirred at a rotation speed of 12000 rpm for 10 minutes, and then spray-dried to obtain tea polyphenol flame retardant particles.

[0023] The oily substance is dimethyl silicone oil, the emulsifier is Span80, the wall material is gelatin, the antioxidant is antioxidant 1035, the lubricant is calcium stearate, and the peroxide crosslinking agent is di-tert-butyl peroxide (DTBP).

[0024] The conductor adopts a round copper conductor structure of twisted copper wires, and the insulation layer adopts cross-linked polyethylene insulation material.

[0025] Example 2 An environmentally friendly fire-resistant cable comprises a conductor, and an insulating layer, a metal shielding layer and an outer sheath layer which are sequentially arranged outside the conductor.

[0026] The outer sheath layer comprises the following raw materials in parts by weight: 85 parts of polyethylene, 12 parts of tea polyphenol flame retardant particles, 1 part of lubricant, 3 parts of antioxidant, and 3 parts of peroxide cross-linking agent.

[0027] The tea polyphenols flame retardant particles are prepared by the following steps: dissolving 18 parts by weight of tea polyphenols in 18 parts by weight of water to prepare a first solution; A second solution was prepared by adding 9 parts by weight of an emulsifier to 75 parts by weight of an oily substance and fully dissolving the emulsifier. The first solution was slowly added to the second solution, and emulsified at 12000 rpm for 20 min to prepare an emulsion; 70 parts by weight of the wall material, 70 parts by weight of water, and 3 parts by weight of phenyl glycidyl ether were mixed to prepare a third solution; The obtained emulsion was added to the third solution, stirred at a rotation speed of 12000 rpm for 20 minutes, and then spray-dried to obtain tea polyphenol flame retardant particles.

[0028] The oily substance is soybean oil, the emulsifier is Span40, the wall material is sodium alginate, the antioxidant is antioxidant 1010, the lubricant is a combination of calcium stearate and stearic acid in a mass ratio of 1:1, and the peroxide crosslinking agent is dicumyl peroxide (DCP). The conductor adopts a round copper conductor structure of twisted copper wires, and the insulation layer adopts cross-linked polyethylene insulation material.

[0029] Example 3 An environmentally friendly fire-resistant cable comprises a conductor, and an insulating layer, a metal shielding layer and an outer sheath layer which are sequentially arranged outside the conductor.

[0030] The outer sheath layer comprises the following raw materials in parts by weight: 80 parts of polyethylene, 10 parts of tea polyphenol flame retardant particles, 0.8 parts of lubricant, 1.5 parts of antioxidant, and 1.5 parts of peroxide crosslinking agent.

[0031] The tea polyphenols flame retardant particles are prepared by the following steps: Dissolving 13 parts by weight of tea polyphenols in 13 parts by weight of water to prepare a first solution; 8 parts by weight of an emulsifier was added to 70 parts by weight of an oily substance and fully dissolved to prepare a second solution; The first solution was slowly added to the second solution, and emulsified at 12000 rpm for 10 min to obtain an emulsion; 50 parts by weight of the wall material, 50 parts by weight of water, and 2 parts by weight of phenyl glycidyl ether were mixed to prepare a third solution; The obtained emulsion was added to the third solution, stirred at a rotation speed of 12000 rpm for 10 minutes, and then spray-dried to obtain tea polyphenol flame retardant particles.

[0032] The oily substance is dimethyl silicone oil, the emulsifier is Span80, the wall material is gelatin, the antioxidant is a combination of antioxidant 1035 and antioxidant 1010 in a mass ratio of 1:1, the lubricant is a combination of calcium stearate, stearic acid and oxidized polyethylene wax in a mass ratio of 1:2:1, and the peroxide crosslinker is benzoyl peroxide (BPO).

[0033] The conductor adopts a round copper conductor structure of twisted copper wires, and the insulation layer adopts cross-linked polyethylene insulation material.

[0034] Example 4 A method for preparing an environmentally friendly fire-resistant cable comprises the following steps: The copper wire is drawn into a wire drawing machine, annealed, and then twisted to obtain a conductor; The insulating material is coated on the conductor by an insulating layer extruder to form an insulating layer; After the formed insulated conductor is cooled and shaped, aluminum foil is wrapped around the surface of the cable core to form a metal shielding layer; The components of the outer sheath layer are melt-blended at 140° C. through an open mill and then extruded onto the outside of the metal shielding layer to form an outer sheath layer, thereby producing an environmentally friendly fire-resistant cable.

[0035] Comparative Example 1 The outer sheath layer of this comparative example does not contain tea polyphenol flame retardant particles, and the rest is the same as Example 3.

[0036] Comparative Example 2 In this comparative example, an equal amount of magnesium hydroxide flame retardant was used to replace the tea polyphenol flame retardant particles, and the rest was the same as in Example 3.

[0037] Result Analysis Test Example 1 Cable flame retardant performance test The cables prepared in Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2 were taken, and their outer sheath layers were peeled off to prepare samples. A JF-5 fully automatic oxygen index tester was used to measure the LOI of a sample with a size of 100 mm × 10 mm in accordance with the standard of GB / T 2406.2-2009. With reference to GB / T 2408-2021, a horizontal vertical combustion tester was used to perform a vertical combustion test on a sample with a size of 130 mm × 13 mm. With reference to ISO 5660-1, a cone calorimeter was used to perform a vertical combustion test at an irradiation intensity of 35 kW / m 2 Under these conditions, the heat release rate and smoke release rate of the test sample during combustion are measured over time, and the maximum heat release rate and maximum smoke release rate are calculated. The test results are shown in the following table: Table 1 Cable flame retardant performance test As shown in the table, the LOI values of the cables in Examples 1-3 ranged from 29.6% to 32.3%, all higher than those of the comparative examples, demonstrating their excellent flame retardancy. This is primarily due to the fact that the tea polyphenols in the tea polyphenol flame-retardant particles produced during thermal decomposition generate active free radicals that disrupt and disrupt the combustion chain reaction, thereby quenching the flame. The released inert gases, such as H2O and CO2, dilute the concentrations of oxygen and combustible gases while simultaneously expanding rapidly. The solid residue gradually accumulates a large number of benzene ring structures, raising its melting point and maintaining a fixed volume, forming a dense, solid surface and porous, loose carbon layer within. This isolates oxygen from the internal polymer, preventing the spread of combustion and ultimately achieving flame retardancy.

[0038] Test Example 2 Cable UV resistance test Cables prepared in Examples 1, 2, and 3, as well as Comparative Examples 1 and 2, had their outer sheaths stripped to prepare test specimens. The specimens were then placed in a test chamber and irradiated with a 6kW xenon lamp for a total exposure time of 1000 hours. The materials were then left at room temperature for 20 hours and observed for signs of aging, such as cracking. Tensile strength and elongation were tested before and after the aging test, and the rate of change (i.e., the ratio of tensile strength and elongation at break after the test to those before the test) was calculated. The test results are shown in the following table.

[0039] Table 2 Cable UV resistance test It can be seen from the table that the tensile strength of the cables of Examples 1 to 3 is 11.2 to 11.5 MPa, and the elongation is 131 to 136, which are not much different from those of the comparative example. However, after aging, the average change rate of the tensile strength of Examples 1 to 3 is 89% and the average change rate of the elongation is 77%, which are significantly higher than those of the comparative example. This is because tea polyphenols have the ability to absorb ultraviolet light, thereby enhancing the anti-ultraviolet aging performance of the cable.

[0040] Test Example 3 Cable antibacterial performance test The cables prepared in Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2 were taken, and their outer sheath layers were peeled off to prepare samples. The samples were cultured in a culture dish at 37°C for 24 hours, and the diameters of the inhibition zones were observed to determine the antibacterial effects. The size d1 at the maximum diameter of the inhibition zones was measured, and then the size d2 at the minimum diameter of the inhibition zones was measured. The arithmetic mean of d1 and d2 was taken as the diameter of the inhibition zones of the group. The test results are shown in the following table.

[0041] Table 3 Inhibition zone size (mm) of different embodiments and comparative examples Note: In common drug sensitivity tests, if the diameter of the bacterial ring is greater than 15 mm, it usually means that the bacteria are highly sensitive to the antibacterial substance; between 10 and 14 mm, it is moderately sensitive; and less than 10 mm, it is lowly sensitive or resistant.

[0042] It can be seen from the table that the antibacterial properties of Examples 1 to 3 are higher than those of the comparative example, indicating that the tea polyphenols in the flame retardant microcapsules of the present invention impart good antibacterial properties to the cable.

[0043] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An environmentally friendly fire-resistant cable comprising a conductor, and an insulation layer, a metal shielding layer, and an outer sheath layer sequentially disposed outside the conductor, characterized in that: The outer sheath layer comprises the following raw materials in parts by weight: 75-85 parts of polyethylene, 8-12 parts of tea polyphenol flame retardant particles, 0.5-1 part of lubricant, 0.5-3 parts of antioxidant, and 0.8-3 parts of peroxide crosslinking agent.

2. The environmentally friendly fire-resistant cable according to claim 1, characterized in that: The tea polyphenols flame retardant particles are prepared by the following steps: dissolving 8 to 18 parts by weight of tea polyphenols in 8 to 18 parts by weight of water to prepare a first solution; A second solution is prepared by adding 6 to 9 parts by weight of an emulsifier to 65 to 75 parts by weight of an oily substance and fully dissolving the emulsifier. Slowly adding the first solution to the second solution, emulsifying at 12000 rpm for 10 to 20 minutes to prepare an emulsion; 30 to 70 parts by weight of the wall material, 30 to 70 parts by weight of water, and 1 to 3 parts by weight of phenyl glycidyl ether are mixed uniformly to prepare a third solution; The obtained emulsion was added to the third solution, stirred at a rotation speed of 12000 rpm for 10 to 20 minutes, and then spray-dried to obtain tea polyphenol flame-retardant particles.

3. The environmentally friendly fire-resistant cable according to claim 2, characterized in that: The oily substance is any one of dimethyl silicone oil, soybean oil and corn oil.

4. The environmentally friendly fire-resistant cable according to claim 2, characterized in that: The emulsifier is any one of Span 40, Span 80 and Tween 60.

5. The environmentally friendly fire-resistant cable according to claim 2, characterized in that: The wall material is any one of gelatin, sodium alginate, ethyl cellulose and methyl cellulose.

6. The environmentally friendly fire-resistant cable according to claim 1, characterized in that: The insulating layer is made of cross-linked polyethylene insulating material.

7. The environmentally friendly fire-resistant cable according to claim 1, characterized in that: The antioxidant is one or more combinations of antioxidant 1035 and antioxidant 1010.

8. The environmentally friendly fire-resistant cable according to claim 1, characterized in that: The lubricant is a combination of one or more of calcium stearate, stearic acid, oxidized polyethylene wax and microcrystalline wax.

9. The environmentally friendly fire-resistant cable according to claim 1, characterized in that: The peroxide crosslinking agent is one or more combinations of dicumyl peroxide (DCP), benzoyl peroxide (BPO), and di-tert-butyl peroxide (DTBP).

10. A method for preparing the environmentally friendly fire-resistant cable according to any one of claims 1 to 9, comprising the following steps: The copper wire is drawn into a wire drawing machine, annealed, and then twisted to obtain a conductor; The insulating material is coated on the conductor by an insulating layer extruder to form an insulating layer; After the formed insulated conductor is cooled and formed, any one of aluminum foil, copper foil and iron foil is wrapped around the insulation layer to form a metal shielding layer; The components of the outer sheath layer are melt-blended at 140° C. through an open mill and then extruded onto the outside of the metal shielding layer to form an outer sheath layer, thereby producing an environmentally friendly fire-resistant cable.

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