Aluminum alloy core fireproof cable and preparation process thereof

Abstract

The invention relates to the technical field of fireproof cables, and provides an aluminum alloy core fireproof cable and a preparation process thereof. An aluminum alloy core fireproof cable comprises a conductor, an insulating layer, a filling layer, a bundling heat insulation layer, an isolation layer, a fireproof layer and a sheath layer which are sequentially arranged from inside to outside, and the sheath layer comprises the following raw materials in parts by weight: 100 parts of polyvinyl chloride, 10-15 parts of a plasticizer, 10-15 parts of an ethylene-vinyl acetate copolymer, 25-30 parts of a flame retardant, 0.5-1.5 parts of an antioxidant, 10-20 parts of a filler and 0.5-1 part of a lubricant. The preparation method of the flame retardant comprises the following steps: mixing calcium oxide, magnesium oxide and zinc oxide, carrying out solid solution annealing to obtain a solid solution, and mixing the solid solution with aluminum hydroxide, ammonium polyphosphate and a metal acetylacetonate complex to obtain the flame retardant. According to the technical scheme, the problem of insufficient flame retardant property of the fireproof cable in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of fireproof cables, and in particular to an aluminum alloy core fireproof cable and a preparation process thereof. Background Art

[0002] Fire-resistant cables, critical components for ensuring the smooth operation of power transmission in extreme conditions like fire, are widely used. Despite the diverse range of fire-resistant cables currently available on the market, many practical issues remain. Some fire-resistant cables struggle to meet increasingly stringent safety standards due to their flame retardancy.

[0003] Polyvinyl chloride is widely used in the sheath layer of fire-resistant cables because of its flame-retardant properties. However, polyvinyl chloride has poor stability at high temperatures. When the temperature is too high, polyvinyl chloride will decompose rapidly, releasing a large amount of smoke and dienes containing double bonds. Dienes containing double bonds are highly flammable substances, which will cause the flame to spread significantly faster, seriously affecting the flame-retardant properties of fire-resistant cables. The smoke produced will also have a strong irritation to the human respiratory system, affecting personnel evacuation and rescue work.

[0004] Therefore, it is necessary to develop an aluminum alloy core fireproof cable with better flame retardant properties. Summary of the Invention

[0005] The present invention provides an aluminum alloy core fireproof cable and a preparation process thereof, which solves the problem of insufficient flame retardancy of fireproof cables in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes an aluminum alloy core fireproof cable, comprising a conductor, an insulation layer, a filling layer, a bundling insulation layer, an isolation layer, a fireproof layer and a sheath layer arranged in sequence from the inside to the outside, the sheath layer comprising the following component raw materials in parts by weight: 100 parts of polyvinyl chloride, 10 to 15 parts of plasticizer, 10 to 15 parts of ethylene-vinyl acetate copolymer, 25 to 30 parts of flame retardant, 0.5 to 1.5 parts of antioxidant, 10 to 20 parts of filler, and 0.5 to 1 part of lubricant. The preparation method of the flame retardant comprises the following steps: mixing calcium oxide, magnesium oxide, and zinc oxide, solution annealing to obtain a solid solution, and mixing the solid solution with aluminum hydroxide, ammonium polyphosphate, and a metal acetylacetonate complex to obtain a flame retardant.

[0007] As a further technical solution, the solution annealing temperature is 500-550°C, for example, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, preferably 500°C, and the time is 8-9h, for example, 8h, 8.1h, 8.2h, 8.3h, 8.4h, 8.5h, 8.6h, 8.7h, 8.8h, 8.9h, 9h, preferably 8h.

[0008] As a further technical solution, the material of the conductor is aluminum alloy.

[0009] The conductor material of the aluminum alloy core fireproof cable of the present invention is aluminum alloy. Aluminum alloy has good thermal conductivity. When the cable encounters a fire, it can quickly disperse and transfer heat to avoid local excessive temperature and accelerate the combustion and decomposition of the insulation layer and the sheath layer, which helps to delay the damage of the fire to the core structure of the cable; at the same time, aluminum alloy has high mechanical strength and excellent corrosion resistance. In a high-temperature fire environment, its structural stability is better than that of traditional pure aluminum conductors. It is not easy to break or deform due to heat, and can maintain the conductive path of the conductor for a certain period of time, providing protection for emergency power supply or signal transmission in a fire. Combined with the excellent flame retardant performance of the sheath layer, the reliability and safety of the entire fireproof cable in a fire scenario are further improved.

[0010] As a further technical solution, the material of the insulating layer is mica tape and silicone tape.

[0011] As a further technical solution, the order of wrapping the insulation layer is to first wrap 2 to 3 layers of mica tape and then wrap 2 to 3 layers of silicone tape.

[0012] As a further technical solution, the material of the filling layer is rock wool rope.

[0013] As a further technical solution, the material used to bundle the thermal insulation layer is glass fiber tape.

[0014] As a further technical solution, the material of the isolation layer is corrugated aluminum.

[0015] As a further technical solution, the fireproof layer is a mineral fireproof layer, the material of the mineral fireproof layer is fireproof mud, and the material of the fireproof mud includes magnesium hydroxide and sodium silicate.

[0016] As a further technical solution, the metal acetylacetonate complex includes one or both of copper acetylacetonate and nickel acetylacetonate.

[0017] In the sheath layer of the aluminum alloy core fire-resistant cable of the present invention, the metal acetylacetonate complex has excellent catalytic activity, can efficiently promote the cross-linking carbonization reaction of the polyvinyl chloride substrate at high temperature, promote the formation of a denser and more stable carbon layer, effectively block heat transfer and oxygen contact, reduce the release of combustible gas, and enhance the flame retardant performance of the sheath layer.

[0018] As a further technical solution, the mass ratio of the calcium oxide, the magnesium oxide and the zinc oxide is 1~2:1:1, and the mass ratio of the solid solution, the aluminum hydroxide, the ammonium polyphosphate and the metal acetylacetonate complex is 2:5:4:0.5~1.

[0019] In the sheath layer of the aluminum alloy core fireproof cable of the present invention, the mass ratio of the solid solution to aluminum hydroxide, ammonium polyphosphate and metal acetylacetonate complex is 2:5:4:0.5~1. The proportions of the four are moderate, which avoids functional conflicts or efficiency losses caused by excessive amounts of a single component, and ultimately significantly improves the flame retardant properties of the sheath layer of the aluminum alloy core fireproof cable.

[0020] As a further technical solution, the ammonium polyphosphate is a composite ammonium polyphosphate, and the preparation method of the composite ammonium polyphosphate includes the following steps: dispersing hydroxydichlorodiphenyl ether in a solvent, adding ammonium polyphosphate, mixing and drying to obtain the composite ammonium polyphosphate.

[0021] In the sheath layer of the aluminum alloy core fireproof cable of the present invention, the ammonium polyphosphate is a composite ammonium polyphosphate. After the ammonium polyphosphate is compounded with hydroxydichlorodiphenyl ether, a heat-resistant and hydrophobic benzene ring structure can be introduced on the surface of the ammonium polyphosphate, thereby slowing down its decomposition rate at high temperature, so that it can expand into carbon more lastingly in a fire. At the same time, chlorine atoms with higher polarity are introduced to enhance the dispersibility and compatibility of the ammonium polyphosphate in the polyvinyl chloride matrix, avoid the problem of uneven flame retardant effect caused by agglomeration of the ammonium polyphosphate, and further improve the flame retardant performance of the fireproof cable.

[0022] As a further technical solution, in the composite ammonium polyphosphate, the mass ratio of the ammonium polyphosphate to the hydroxydichlorodiphenyl ether is 20:2~2.5.

[0023] As a further technical solution, the solvent is dichloromethane, and the mass ratio of the solvent to the ammonium polyphosphate is 3 to 5:1, for example, 3:1, 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1, 5:1, preferably 4:1.

[0024] As a further technical solution, the mixing time is 3 to 4 hours, for example, it can be 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours, 4 hours, preferably 3.5 hours.

[0025] As a further technical solution, the plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, and diisooctyl phthalate, preferably dioctyl phthalate.

[0026] A plasticizer is added to the sheath layer of the aluminum alloy core fireproof cable of the present invention. The plasticizer can be inserted between the polyvinyl chloride molecular chains, weakening the intermolecular force and reducing the melt viscosity, making the sheath layer material easier to flow during the extrusion and molding process, reducing processing energy consumption, ensuring the continuous and stable production of the cable sheath, and avoiding molding defects caused by the material being too hard.

[0027] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 264, preferably antioxidant 1010.

[0028] An antioxidant is added to the sheath layer of the aluminum alloy core fireproof cable of the present invention. Polyvinyl chloride is prone to oxidation reaction during high-temperature processing or long-term use, resulting in molecular chain breakage and degradation of mechanical properties. The antioxidant can capture free radicals generated in the oxidation reaction, terminate the chain reaction, delay material aging, and extend the service life of the cable sheath.

[0029] As a further technical solution, the filler includes one or both of calcium carbonate and talc, preferably talc.

[0030] Fillers are added to the sheath layer of the aluminum alloy core fireproof cable of the present invention. The fillers can improve the rigidity of the material through the particle reinforcement effect, adjust the melt fluidity of the material, and reduce problems such as melt fracture and mold sticking during the processing process; the filler is preferably talcum powder. The flaky structure of talcum powder can reduce the internal friction of the melt, improve the melt fluidity of the material, and make the processing process smoother. At the same time, the layered structure of talcum powder can enhance the barrier and heat resistance of the material, especially in a high temperature environment, it can reduce the penetration of heat and oxygen, and indirectly assist the antioxidant and flame retardant to play their role.

[0031] As a further technical solution, the lubricant includes one or both of calcium stearate and zinc stearate, preferably zinc stearate.

[0032] A lubricant is added to the sheath layer of the aluminum alloy core fireproof cable of the present invention. During the material melt processing, the lubricant can reduce the internal friction between resin molecules and the external friction between the melt and the surface of the processing equipment, thereby reducing the melt viscosity, making the material easier to flow and fill the mold, and avoiding increased processing energy consumption or equipment wear due to excessive friction; at the same time, the lubricant can reduce surface defects of the material during the molding process, making the surface of the product smoother and flatter, improving its surface finish and consistency, and reducing the risk of stress concentration in later use.

[0033] The present invention also provides a method for preparing an aluminum alloy core fireproof cable, which is used to prepare the aluminum alloy core fireproof cable, comprising the following steps: S1. Wrapping an insulating layer material around the conductor to form an insulating layer, and sequentially arranging a filling layer, a bundling insulation layer, an isolation layer, and a fireproof layer outside the insulating layer to obtain a semi-finished product; S2. Evenly mix the raw materials for the sheath layer, and extrude the raw materials onto the outside of the semi-finished product to obtain an aluminum alloy core fireproof cable.

[0034] The working principle and beneficial effects of the present invention are: In the sheath layer of the aluminum alloy core fireproof cable of the present invention, the flame retardant is prepared by mixing a solid solution composed of calcium oxide, magnesium oxide and zinc oxide with aluminum hydroxide, ammonium polyphosphate and a metal acetylacetonate complex, which effectively suppresses the smoke released by the combustion of polyvinyl chloride and improves the flame retardant performance of the fireproof cable. In the prior art, when polyvinyl chloride is used as the main raw material for the cable sheath layer, the combustion of polyvinyl chloride will release a large amount of smoke and flammable substances, seriously affecting the flame retardant performance of the fireproof cable. In the sheath layer of the aluminum alloy core fireproof cable of the present invention, a solid solution is first prepared from calcium oxide, magnesium oxide and zinc oxide, which can reduce the amount of organic smoke generated by the decomposition of polyvinyl chloride; aluminum hydroxide decomposes at high temperature to absorb heat and release water vapor, achieving cooling and oxygen dilution; ammonium polyphosphate promotes the formation of an expanded carbon layer, strengthening the barrier to heat and oxygen; the metal acetylacetonate complex catalyzes and promotes carbonization, improving the density of the carbon layer, and multiple flame retardants cooperate with each other to comprehensively suppress the combustion reaction, effectively suppress the spread of flames, and improve the flame retardant performance of the fireproof cable. DETAILED DESCRIPTION

[0035] 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 embodiments described 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 making any creative efforts are within the scope of protection of the present invention.

[0036] In the following examples and comparative examples: Polyvinyl chloride: model SG-5; Calcium oxide: average particle size is 325 mesh; Magnesium oxide: average particle size is 1 μm; Zinc oxide: average particle size is 100 mesh; Talc: average particle size is 325 mesh; Ammonium polyphosphate: average particle size is 325 mesh; Aluminum hydroxide: average particle size is 8000 mesh.

[0037] Example 1 A method for preparing an aluminum alloy core fireproof cable comprises the following steps: S1. Wrap two layers of mica tape around the aluminum alloy conductor, then wrap two layers of silicone tape around it to form an insulation layer. Then, arrange a rock wool rope filling layer, a glass fiber tape bundling insulation layer, a corrugated aluminum isolation layer, and a fireproof mud fireproof layer on the outside of the insulation layer to obtain a semi-finished product; S2, 100 parts of polyvinyl chloride, 10 parts of dioctyl phthalate, 10 parts of ethylene-vinyl acetate copolymer, 25 parts of flame retardant, 0.5 parts of antioxidant 1010, 10 parts of talc, and 0.5 parts of zinc stearate are mixed evenly, and extruded onto the semi-finished product to obtain an aluminum alloy core fireproof cable; The preparation method of the flame retardant includes the following steps: mixing calcium oxide, magnesium oxide, and zinc oxide (mass ratio is 1:1:1), annealing at 500°C for 8 hours to obtain a solid solution, and mixing the solid solution with aluminum hydroxide, ammonium polyphosphate, and copper acetylacetonate (mass ratio is 2:5:4:0.5) to obtain a flame retardant.

[0038] Example 2 A method for preparing an aluminum alloy core fireproof cable comprises the following steps: S1. Wrap two layers of mica tape around the aluminum alloy conductor, then wrap two layers of silicone tape around it to form an insulation layer. Then, arrange a rock wool rope filling layer, a glass fiber tape bundling insulation layer, a corrugated aluminum isolation layer, and a fireproof mud fireproof layer on the outside of the insulation layer to obtain a semi-finished product; S2, 100 parts of polyvinyl chloride, 12 parts of dioctyl phthalate, 12 parts of ethylene-vinyl acetate copolymer, 28 parts of flame retardant, 1 part of antioxidant 1010, 15 parts of talc, and 0.8 parts of zinc stearate are mixed evenly, and extruded onto the semi-finished product to obtain an aluminum alloy core fireproof cable; The preparation method of the flame retardant includes the following steps: mixing calcium oxide, magnesium oxide, and zinc oxide (mass ratio is 1:1:1), annealing at 500°C for 8 hours to obtain a solid solution, and mixing the solid solution with aluminum hydroxide, ammonium polyphosphate, and copper acetylacetonate (mass ratio is 2:5:4:0.5) to obtain a flame retardant.

[0039] Example 3 A method for preparing an aluminum alloy core fireproof cable comprises the following steps: S1. Wrap three layers of mica tape around the aluminum alloy conductor, then wrap three layers of silicone tape around it to form an insulation layer. Then, arrange a rock wool rope filling layer, a glass fiber tape bundling insulation layer, a corrugated aluminum isolation layer, and a fireproof mud fireproof layer on the outside of the insulation layer to obtain a semi-finished product; S2, 100 parts of polyvinyl chloride, 15 parts of dioctyl phthalate, 15 parts of ethylene-vinyl acetate copolymer, 30 parts of flame retardant, 1.5 parts of antioxidant 1010, 20 parts of talc, and 1 part of zinc stearate are mixed evenly, and extruded onto the semi-finished product to obtain an aluminum alloy core fireproof cable; The preparation method of the flame retardant includes the following steps: mixing calcium oxide, magnesium oxide, and zinc oxide (mass ratio is 1:1:1), annealing at 500°C for 8 hours to obtain a solid solution, and mixing the solid solution with aluminum hydroxide, ammonium polyphosphate, and copper acetylacetonate (mass ratio is 2:5:4:0.5) to obtain a flame retardant.

[0040] Example 4 Compared with Example 2, the difference of Example 4 is that the mass ratio of calcium oxide, magnesium oxide and zinc oxide is 2:1:1.

[0041] Example 5 Compared with Example 4, Example 5 is different in that the mass ratio of the solid solution, aluminum hydroxide, ammonium polyphosphate and copper acetylacetonate is 2:5:4:1.

[0042] Example 6 Compared with Example 5, Example 6 is different in that copper acetylacetonate is replaced by an equal amount of nickel acetylacetonate.

[0043] Example 7 Compared with Example 5, the difference of Example 7 is that the ammonium polyphosphate is replaced by an equal amount of composite ammonium polyphosphate prepared by the following preparation method; The preparation method of composite ammonium polyphosphate comprises the following steps: dispersing hydroxy dichlorodiphenyl ether in dichloromethane, adding ammonium polyphosphate, wherein the mass ratio of hydroxy dichlorodiphenyl ether to ammonium polyphosphate is 2:20, and the mass ratio of dichloromethane to ammonium polyphosphate is 4:1, mixing for 3.5 hours and then drying to obtain composite ammonium polyphosphate.

[0044] Example 8 Compared with Example 7, the difference in Example 8 is that the mass ratio of hydroxydichlorodiphenyl ether to ammonium polyphosphate is 2.5:20.

[0045] Comparative Example 1 Compared with Example 2, the difference in Comparative Example 1 is that the solid solution prepared by mixing calcium oxide, magnesium oxide and zinc oxide is not added, and the flame retardant is composed of aluminum hydroxide, ammonium polyphosphate and copper acetylacetonate in a mass ratio of 5:4:0.5.

[0046] Comparative Example 2 Compared with Example 2, the difference of Comparative Example 2 is that copper acetylacetonate is not added, and the flame retardant consists of a solid solution, aluminum hydroxide and ammonium polyphosphate in a mass ratio of 2:5:4.

[0047] Comparative Example 3 Compared with Example 2, the difference of Comparative Example 3 is that the solid solution consists of calcium oxide and zinc oxide in a mass ratio of 1:1.

[0048] Comparative Example 4 Compared with Example 2, Comparative Example 4 is different in that copper acetylacetonate is replaced by an equal amount of copper stearate.

[0049] Experimental Example 1 The sheath layer of the aluminum alloy core fire-resistant cable prepared in Examples 1 to 8 and Comparative Examples 1 to 4 was subjected to an oxygen index test according to the test method specified in GB / T2406.2-2009 "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.

[0050] The test results are shown in Table 1: Table 1 Performance test results of aluminum alloy core fireproof cables prepared in Examples 1 to 8 and Comparative Examples 1 to 4

[0051] It can be seen from Table 1 that when the flame retardant consists of a solid solution, aluminum hydroxide, ammonium polyphosphate and a metal acetylacetonate complex, and the solid solution consists of calcium oxide, magnesium oxide and zinc oxide, the flame retardant performance of the aluminum alloy core fire-resistant cable can be improved.

[0052] When the composite ammonium polyphosphate prepared by compounding with hydroxydichlorodiphenyl ether is added, the flame retardant properties of the aluminum alloy core fireproof cable can be further improved.

[0053] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An aluminum alloy core fireproof cable, characterized in that: The invention comprises a conductor, an insulating layer, a filling layer, a bundled heat-insulating layer, an isolation layer, a fireproof layer and a sheath layer, which are sequentially arranged from the inside to the outside. The sheath layer comprises the following component raw materials in parts by weight: 100 parts of polyvinyl chloride, 10-15 parts of a plasticizer, 10-15 parts of an ethylene-vinyl acetate copolymer, 25-30 parts of a flame retardant, 0.5-1.5 parts of an antioxidant, 10-20 parts of a filler and 0.5-1 part of a lubricant. The preparation method of the flame retardant comprises the following steps: mixing calcium oxide, magnesium oxide and zinc oxide, performing solid solution annealing to obtain a solid solution, and mixing the solid solution with aluminum hydroxide, ammonium polyphosphate and a metal acetylacetonate complex to obtain the flame retardant.

2. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The material of the conductor is aluminum alloy.

3. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The insulating layer is made of mica tape and silicone tape.

4. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The metal acetylacetonate complex comprises one or both of copper acetylacetonate and nickel acetylacetonate.

5. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The mass ratio of the calcium oxide, the magnesium oxide and the zinc oxide is 1-2:1:1, and the mass ratio of the solid solution, the aluminum hydroxide, the ammonium polyphosphate and the metal acetylacetonate complex is 2:5:4:0.5-1.

6. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The ammonium polyphosphate is a composite ammonium polyphosphate. The preparation method of the composite ammonium polyphosphate comprises the following steps: dispersing hydroxydichlorodiphenyl ether in a solvent, adding ammonium polyphosphate, mixing and drying to obtain the composite ammonium polyphosphate.

7. The aluminum alloy core fireproof cable according to claim 6, characterized in that: In the composite ammonium polyphosphate, the mass ratio of the ammonium polyphosphate to the hydroxydichlorodiphenyl ether is 20:2-2.

5.

8. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, and diisooctyl phthalate.

9. The aluminum alloy core fireproof cable according to claim 1, characterized in that: The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 264; The filler includes one or both of calcium carbonate and talc; The lubricant includes one or both of calcium stearate and zinc stearate.

10. A process for preparing an aluminum alloy core fireproof cable, used for preparing an aluminum alloy core fireproof cable according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Wrapping an insulating layer material around the conductor to form an insulating layer, and sequentially arranging a filling layer, a bundling insulation layer, an isolation layer, and a fireproof layer outside the insulating layer to obtain a semi-finished product; S2. Evenly mix the raw materials for the sheath layer, and extrude the raw materials onto the outside of the semi-finished product to obtain an aluminum alloy core fireproof cable.

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