A high-temperature resistant and fireproof flexible cable and its preparation method

Abstract

This invention discloses a high-temperature fire-resistant flexible cable and its preparation method, belonging to the field of fire-resistant cable technology. The high-temperature fire-resistant flexible cable includes a first outer sheath, a second outer sheath on the inner wall of the first outer sheath, and armor on the inner wall of the second outer sheath. This invention features a first, third, fourth, and fifth outer sheath, all made of magnesium-containing flame retardant material. Performance tests of the magnesium-containing flame retardant show low flame spread, low total calorific value release, high tensile strength, and low smoke density. At high temperatures, the chemical properties of magnesium in the magnesium-containing flame retardant release moisture, which helps to lower the combustion temperature and inhibit flame spread, resulting in strong fire resistance and high-temperature resistance. When the first outer sheath burns, the magnesium-containing flame retardant is typically halogen-free, producing fewer harmful gases and is more environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of fire-resistant cable technology, specifically relating to a high-temperature resistant fire-resistant flexible cable and its preparation method. Background Technology

[0002] A cable is an electrical transmission line consisting of one or more conductors and their insulation material. Its main function is to transmit power, signals, or data. It is widely used in power systems, communication networks, and various industrial equipment. High-temperature fire-resistant cables are the most common type. They are used to maintain functionality and safety in the event of a fire. They are mainly used in important power and communication systems to ensure that power or signals can continue to be transmitted in the event of a fire.

[0003] Existing high-temperature fireproof cables have a relatively simple structural design, usually using simple fireproof materials for protection, and only protecting the outer layer of the cable. The protection performance is poor. In the event of a fire, the outer protective sheath of the cable cannot withstand the high temperature of combustion, causing the cable to be damaged and deformed, and unable to operate normally and stably. At the same time, existing fireproof materials produce harmful gases when burning, affecting the health of people in the surrounding area. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant fireproof flexible cable and its preparation method.

[0005] The technical solution adopted to solve the above technical problems is: a high-temperature fire-resistant flexible cable, including a first outer sheath, a second outer sheath provided on the inner wall of the first outer sheath, and an armor provided on the inner wall of the second outer sheath. The first outer sheath is made of a magnesium-containing flame retardant material. In the performance test of the magnesium-containing flame retardant, the flame spread is low, the total calorific value released is low, the tensile strength is high, and the smoke density is low. Moreover, at high temperatures, the chemical properties of magnesium in the magnesium-containing flame retardant will release moisture, which helps to reduce the combustion temperature and inhibit flame spread. It has strong fire resistance and high temperature resistance. When the first outer sheath is burning, the magnesium-containing flame retardant is usually halogen-free and produces less harmful gas, making it more environmentally friendly. In the event of a fire, it enables the cable to operate stably and maintain normal operation. The second outer sheath is made of aramid fiber, which can maintain stability in high-temperature environments and has good heat resistance, greatly improving the fire resistance and flame retardant effect of the cable and further protecting the main components. When the cable is transported and laid, the armor provides physical protection to prevent deformation under external pressure.

[0006] The inner wall of the armor is provided with an inner sheath, the inner wall of the inner sheath is provided with a wrapping layer, and the inner wall of the wrapping layer is provided with a first filling layer. The inner sheath provides protection for the wrapping layer, the wrapping layer can protect the internal material from the influence of the external environment and prevent corrosion and degradation, and the first filling layer can increase the overall strength and stability of the material and provide support for the main body component, multiple secondary conductor components and multiple control components.

[0007] The first filling layer contains a main conductor assembly, and multiple secondary conductor assemblies are arranged around the main conductor assembly within the first filling layer. Each secondary conductor assembly includes a secondary core conductor disposed within the first filling layer. The outer wall of the secondary core conductor is covered by a secondary conductor insulation component, and the outer wall of the secondary conductor insulation component is covered by a fourth outer sheath. The outer wall of the fourth outer sheath has a pressure-resistant sleeve. The secondary core conductor is made of copper, possessing excellent conductivity, effectively transmitting current and reducing energy loss. The secondary conductor insulation component prevents current leakage from the secondary core conductor to the external environment, ensuring current flows along the correct path and providing physical protection for the secondary core conductor. Furthermore, when the main core conductor is damaged, signals can be transmitted through multiple secondary core conductors for backup, without affecting normal signal transmission. The fourth outer sheath is made of a magnesium-containing flame-retardant material, exhibiting high temperature resistance and strong fire resistance. When the first outer sheath is burned, the secondary core conductor is doubly protected by the fourth outer sheath, ensuring the secondary core conductor... The system is designed for stable operation. Multiple control components are located around the main component within the first filling layer. Each control component includes a second filling layer within the first filling layer. The outer wall of the second filling layer is covered by a fifth outer sheath. Multiple control conductor insulation components are located at the center of the second filling layer. The inner walls of each control conductor insulation component are equipped with control conductor shields. Each control conductor shield has a control conductor core at its inner center. The control conductor core can quickly locate damaged points, facilitating rapid repair by personnel. The control conductor shields are protected from external electromagnetic influences, reducing interference with surrounding equipment. The control conductor shields also reduce electromagnetic interference, ensuring stable signal transmission. The second filling layer provides support for the multiple control conductor cores. The fifth outer sheath is made of magnesium-containing flame-retardant material, exhibiting high temperature resistance and strong fire resistance. When the first outer sheath is burned, the control conductor core is double-protected by the fifth outer sheath, ensuring stable operation.

[0008] Furthermore, the main body assembly includes a main conductor disposed within a first filler layer, the outer wall of the main conductor being covered by a main body insulation component, and the outer wall of the main body insulation component being covered by a third outer sheath.

[0009] Through the above technical solution, the main conductor is made of copper, which has excellent electrical conductivity and can effectively transmit current and reduce energy loss. The main insulation component prevents current from leaking from the main conductor to the external environment, ensuring that the current flows along the correct path, and at the same time provides physical protection for the main conductor. The third outer sheath is made of magnesium flame retardant material, which is resistant to high temperature and has strong fire resistance. When the first outer sheath is burned, the main conductor is protected by the third outer sheath, so that the main conductor can operate stably.

[0010] Furthermore, the outer wall of the fourth outer sheath is fixedly connected with multiple supporting arches, and the inner wall of the pressure-resistant sleeve is provided with multiple buffer arches, with the multiple buffer arches covering the corresponding supporting arches.

[0011] Through the above technical solution, when the pressure-resistant sleeve is subjected to external pressure, the pressure-resistant sleeve transmits the pressure to multiple buffer arches, so that the multiple buffer arches buffer the applied pressure. At the same time, the multiple buffer arches transmit the pressure to the corresponding support arches, so that the multiple support arches disperse the pressure and improve their load-bearing capacity, thereby reducing the squeezing of the fourth outer sheath and preventing excessive pressure from deforming the secondary conductor assembly.

[0012] A method for preparing a high-temperature resistant and fire-resistant flexible cable includes the following specific steps:

[0013] Step 1: The main body insulation component is sprayed onto the outer wall of the main conductor using an electrocoating device, and then the third outer sheath is wrapped onto the outer wall of the main body insulation component using a twin-screw extruder to complete the processing of the main conductor.

[0014] Step 2: The secondary conductor insulation component is sprayed onto the outer wall of the secondary conductor using an electrocoating device. Then, the fourth outer sheath is wrapped around the outer wall of the secondary conductor insulation component using a twin-screw extruder. Finally, the pressure-resistant sleeve is wrapped around the outside of the fourth outer sheath to complete the processing of the secondary conductor.

[0015] Step 3: Use a hot air gun to heat and bond the cut control conductor shield to the outer wall of the control conductor core. Use an electrocoating device to spray the control conductor insulation components onto the outer wall of the control conductor shield. Then, use a twin-screw extruder to wrap the fifth outer sheath around the outside of multiple control conductor insulation components. Finally, use a filling machine to fill the inside with a second filling layer to ensure airtightness.

[0016] Step 4: The wrapping machine wraps the main conductor assembly, multiple secondary conductor assemblies, and multiple control assemblies with a wrapping layer. The inside is filled with a first filler layer by a filling machine to ensure airtightness. The inner sheath is extruded and wrapped around the outside of the wrapping layer by a twin-screw extruder. The armor is wrapped around the outside of the inner sheath by an armoring machine to ensure good sealing at the joints and ports of the armor to prevent moisture and impurities from entering. The second outer sheath is then extruded and wrapped around the outside of the armor by a twin-screw extruder. Finally, the first outer sheath is extruded and wrapped around the outside of the second outer sheath by a twin-screw extruder, completing the cable preparation.

[0017] The materials of the first outer sheath, the third outer sheath, the fourth outer sheath, and the fifth outer sheath are all magnesium-containing flame retardants. The magnesium-containing flame retardant includes the following raw materials in parts by weight: 60-70 parts of polyethylene, 35-45 parts of magnesium hydroxide, 6-10 parts of hydrotalcite, and 0.06-3 parts of phthalate coupling agent.

[0018] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0019] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add calcium carbonate and heat and stir.

[0020] S2. Add titanate coupling agent to the reaction vessel and continue stirring;

[0021] S3. Filter the mixture in the reactor, then dry it, and after drying, sieve it to obtain the magnesium-containing flame retardant product.

[0022] Furthermore, the mass of calcium carbonate added in S1 is 3-5 parts, and the heating and stirring temperature is 60-80℃.

[0023] Furthermore, the stirring time in S2 is 10-15 minutes.

[0024] Furthermore, in step S3, the drying temperature is 100~120℃ and the drying time is 40~50min.

[0025] The beneficial effects of the present invention are as follows: (1) The present invention is designed with a first outer sheath, a third outer sheath, a fourth outer sheath and a fifth outer sheath, all of which are made of magnesium flame retardant material. In the performance test of magnesium flame retardant, the flame spread is low, the total heat value released is low, the tensile strength is high and the smoke density is low. At high temperature, the chemical properties of magnesium in magnesium flame retardant will release moisture, which helps to reduce the combustion temperature and inhibit flame spread. It has strong fire resistance and high temperature resistance. When the first outer sheath is burning, magnesium flame retardant is usually halogen-free and produces less harmful gas, which is more environmentally friendly; (2) The present invention is designed with a main conductor assembly, a secondary conductor assembly and a control conductor insulation component. The protective sleeves are all made of magnesium flame retardant material, which provides double protection. In the event of a fire, the cable can operate stably and maintain normal operation. When the main conductor is damaged, the signal can be transmitted through multiple secondary conductors for backup use without affecting normal signal transmission. Multiple control conductors can quickly locate the damaged point, which helps the staff to repair it quickly and greatly improves the service life of the cable. Attached Figure Description

[0026] Figure 1 This is an appearance drawing of the present invention;

[0027] Figure 2 This is the front view of the present invention;

[0028] Figure 3 This is a cross-sectional view of the main component of the present invention;

[0029] Figure 4 This is a schematic diagram of the secondary conductor assembly structure of the present invention;

[0030] Figure 5 This is a schematic diagram of the control component structure of the present invention;

[0031] Figure 6 for Figure 1 A magnified view of a section at point A in the middle;

[0032] Figure 7 for Figure 4 A magnified view of a section at point B in the middle.

[0033] Reference numerals: 1. First outer sheath; 2. Second outer sheath; 3. Armor; 4. Inner sheath; 5. Wrapping layer; 6. First filler layer; 7. Main conductor assembly; 701. Main conductor core; 702. Main conductor insulation component; 703. Third outer sheath; 8. Secondary conductor assembly; 801. Secondary conductor core; 802. Secondary conductor insulation component; 803. Fourth outer sheath; 8031. Support arch; 804. Compression sleeve; 8041. Buffer arch; 9. Control assembly; 901. Second filler layer; 902. Fifth outer sheath; 903. Control conductor insulation component; 904. Control conductor shield; 905. Control conductor core. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] like Figures 1-7 As shown in this embodiment, a high-temperature fire-resistant flexible cable includes a first outer sheath 1, a second outer sheath 2 on the inner wall of the first outer sheath 1, and an armor 3 on the inner wall of the second outer sheath 2. The first outer sheath 1 is made of a magnesium-containing flame retardant material. In performance tests, the magnesium-containing flame retardant exhibits low flame spread, low total calorific value release, high tensile strength, and low smoke density. Furthermore, at high temperatures, the chemical properties of magnesium in the magnesium-containing flame retardant release moisture, which helps to lower the combustion temperature and inhibit flame spread, resulting in strong fire resistance and high-temperature resistance. When the first outer sheath 1 burns, the magnesium-containing flame retardant is typically halogen-free, producing fewer harmful gases and is more environmentally friendly. In fire conditions, this allows the cable to operate stably and maintain normal cable operation. The outer sheath 2 is made of aramid fiber, which can maintain stability in high-temperature environments and has good heat resistance, greatly improving the fire resistance and flame retardancy of the cable, and further protecting the main conductor assembly 7. When the cable is transported and laid, the armor 3 provides physical protection to prevent deformation under external pressure. The inner wall of the armor 3 is provided with an inner sheath 4, the inner wall of the inner sheath 4 is provided with a wrapping layer 5, and the inner wall of the wrapping layer 5 is provided with a first filling layer 6. The inner sheath 4 provides protection for the wrapping layer 5. The wrapping layer 5 can protect the internal materials from the influence of the external environment and prevent corrosion and degradation. The first filling layer 6 can increase the overall strength and stability of the materials and provide support for the main conductor assembly 7, multiple secondary conductor assemblies 8 and multiple control components 9.

[0036] like Figures 1-3 As shown, a main conductor assembly 7 is provided within the first filling layer 6. The main conductor assembly 7 includes a main conductor core 701 disposed within the first filling layer 6. The outer wall of the main conductor core 701 is covered with a main conductor insulation component 702, and the outer wall of the main conductor insulation component 702 is covered with a third outer sheath 703. The main conductor core 701 is made of copper and has excellent electrical conductivity, enabling it to effectively transmit current and reduce energy loss. The main conductor insulation component 702 prevents current from leaking from the main conductor core 701 into the external environment, ensuring that the current flows along the correct path, and at the same time provides physical protection for the main conductor core 701. The third outer sheath 703 is made of a magnesium-containing flame retardant material, which is resistant to high temperatures and has strong fire resistance. When the first outer sheath 1 is burned, the main conductor core 701 is doubly protected by the third outer sheath 703, enabling the main conductor core 701 to operate stably.

[0037] like Figures 1-4As shown, multiple secondary conductor assemblies 8 are arranged around the main conductor assembly 7 within the first filling layer 6. Each secondary conductor assembly 8 includes a secondary core conductor 801 disposed within the first filling layer 6. The outer wall of the secondary core conductor 801 is covered by a secondary conductor insulation component 802, and the outer wall of the secondary conductor insulation component 802 is covered by a fourth outer sheath 803. The secondary core conductor 801 is made of copper, possessing excellent conductivity, enabling effective current transmission and reducing energy loss. The secondary conductor insulation component 802 prevents current leakage from the secondary core conductor 801 into the external environment, ensuring current flows along the correct path. It also provides physical protection for the secondary core conductor 801. Furthermore, when the main core conductor 701 is damaged, signals can be transmitted through multiple secondary core conductors 801 for backup use, without affecting normal signal transmission. The fourth outer sheath 803 is made of a magnesium-containing flame-retardant material, resistant to high temperatures and fire-resistant. With strong fire resistance, when the first outer sheath 1 is burned, the secondary conductor 801 is doubly protected by the fourth outer sheath 803, enabling the secondary conductor 801 to operate stably. The outer wall of the fourth outer sheath 803 is fixedly connected with multiple supporting arches 8031, and the inner wall of the pressure-resistant sleeve 804 is provided with multiple buffer arches 8041. The multiple buffer arches 8041 cover the corresponding supporting arches 8031. When the pressure-resistant sleeve 804 is subjected to external pressure, the pressure-resistant sleeve 804 transmits the pressure to the multiple buffer arches 8041, so that the multiple buffer arches 8041 buffer the applied pressure. At the same time, the multiple buffer arches 8041 transmit the pressure to the corresponding supporting arches 8031, so that the multiple supporting arches 8031 ​​disperse the pressure, improve their load-bearing capacity, thereby reducing the squeezing of the fourth outer sheath 803 and preventing excessive pressure from deforming the secondary conductor assembly 8.

[0038] like Figures 1-5 As shown, multiple control components 9 are arranged around the first filling layer 6 near the main body assembly 7. Each control component 9 includes a second filling layer 901 disposed within the first filling layer 6. The outer wall of the second filling layer 901 is covered by a fifth outer sheath 902. Multiple control conductor insulating components 903 are arranged at the center of the second filling layer 901. Control conductor shields 904 are provided on the inner walls of each of the multiple control conductor insulating components 903. Control conductor cores 905 are arranged at the center of each of the multiple control conductor shields 904. The control conductor cores 905 can quickly locate damaged components. The first outer sheath 902 is made of magnesium-containing flame retardant material, which is resistant to high temperatures and has strong fire resistance. When the first outer sheath 1 is burned, the fifth outer sheath 902 provides double protection for the control conductor 905, enabling the control conductor 905 to operate stably. The second filling layer 901 provides support for multiple control conductors 905. The fifth outer sheath 902 provides double protection for the control conductor 905, enabling the control conductor 905 to operate stably.

[0039] A method for preparing a high-temperature resistant and fire-resistant flexible cable includes the following specific steps:

[0040] Step 1: The main body insulation component 702 is sprayed onto the outer wall of the main conductor 701 using an electrocoating device, and then the third outer sheath 703 is wrapped around the outer wall of the main body insulation component 702 using a twin-screw extruder, thus completing the processing of the main conductor 701.

[0041] Step 2: The secondary conductor insulation component 802 is sprayed onto the outer wall of the secondary conductor 801 using an electrocoating device. Then, the fourth outer sheath 803 is wrapped around the outer wall of the secondary conductor insulation component 802 using a twin-screw extruder. Finally, the pressure-resistant sleeve 804 is wrapped around the outside of the fourth outer sheath 803 to complete the processing of the secondary conductor 801.

[0042] Step 3: Use a hot air gun to heat and bond the cut control conductor shield 904 to the outer wall of the control conductor core 905. Use an electrocoating device to spray the control conductor insulation component 903 onto the outer wall of the control conductor shield 904. Then, use a twin-screw extruder to wrap the fifth outer sheath 902 around the outside of multiple control conductor insulation components 903. Finally, use a filling machine to fill the inside with a second filling layer 901 to ensure airtightness.

[0043] Step 4: The wrapping layer 5 is wrapped around the outside of the main conductor assembly 7, multiple secondary conductor assemblies 8, and multiple control components 9 using a wrapping machine. The inside is filled with the first filling layer 6 using a filling machine to ensure airtightness. The inner sheath 4 is extruded and wrapped around the outside of the wrapping layer 5 using a twin-screw extruder. The armor 3 is wrapped around the outside of the inner sheath 4 using an armoring machine to ensure good sealing at the joints and ports of the armor 3 to prevent moisture and impurities from entering. The second outer sheath 2 is then extruded and wrapped around the outside of the armor 3 using a twin-screw extruder. Finally, the first outer sheath 1 is extruded and wrapped around the outside of the second outer sheath 2 using a twin-screw extruder, completing the cable preparation.

[0044] Preparation of magnesium-containing flame retardant materials:

[0045] Example 1:

[0046] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 60 parts polyethylene, 35 parts magnesium hydroxide, 6 parts hydrotalcite, 0.06 parts phthalate coupling agent, and 3 parts calcium carbonate.

[0047] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0048] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 3 parts of calcium carbonate and heat to 60°C and stir.

[0049] S2. Add 0.06 parts of titanate coupling agent to the reaction vessel and continue stirring for 10 minutes;

[0050] S3. Filter the mixture in the reactor, then dry it at 100°C for 40 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0051] Example 2:

[0052] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 65 parts polyethylene, 40 parts magnesium hydroxide, 8 parts hydrotalcite, 0.15 parts phthalate coupling agent, and 4 parts calcium carbonate.

[0053] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0054] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 4 parts of calcium carbonate and heat to 60°C and stir.

[0055] S2. Add 0.15 parts of titanate coupling agent to the reaction vessel and continue stirring for 10 minutes;

[0056] S3. Filter the mixture in the reactor, then dry it at 100°C for 40 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0057] Example 3:

[0058] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 70 parts polyethylene, 45 parts magnesium hydroxide, 10 parts hydrotalcite, 3 parts phthalate coupling agent, and 6 parts calcium carbonate.

[0059] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0060] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 6 parts of calcium carbonate and heat to 60°C and stir.

[0061] S2. Add 3 parts of titanate coupling agent to the reaction vessel and continue stirring for 10 minutes;

[0062] S3. Filter the mixture in the reactor, then dry it at 100°C for 40 minutes. After drying, sieve the mixture to obtain the magnesium-containing flame retardant product.

[0063] Example 4:

[0064] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 60 parts polyethylene, 35 parts magnesium hydroxide, 6 parts hydrotalcite, 0.06 parts phthalate coupling agent, and 3 parts calcium carbonate.

[0065] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0066] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 3 parts of calcium carbonate and heat to 70°C and stir.

[0067] S2. Add 0.06 parts of titanate coupling agent to the reaction vessel and continue stirring for 12 minutes;

[0068] S3. Filter the mixture in the reactor, then dry it at 110°C for 45 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0069] Example 5:

[0070] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 60 parts polyethylene, 35 parts magnesium hydroxide, 6 parts hydrotalcite, 0.06 parts phthalate coupling agent, and 3 parts calcium carbonate.

[0071] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0072] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 3 parts of calcium carbonate and heat to 80°C while stirring.

[0073] S2. Add 0.06 parts of titanate coupling agent to the reaction vessel and continue stirring for 15 minutes;

[0074] S3. Filter the mixture in the reactor, then dry it at 120°C for 50 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0075] Example 6:

[0076] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 65 parts polyethylene, 40 parts magnesium hydroxide, 8 parts hydrotalcite, 0.15 parts phthalate coupling agent, and 4 parts calcium carbonate.

[0077] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0078] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 4 parts of calcium carbonate and heat to 70°C while stirring.

[0079] S2. Add 0.15 parts of titanate coupling agent to the reaction vessel and continue stirring for 12 minutes;

[0080] S3. Filter the mixture in the reactor, then dry it at 110°C for 45 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0081] Example 7:

[0082] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 65 parts polyethylene, 40 parts magnesium hydroxide, 8 parts hydrotalcite, 0.15 parts phthalate coupling agent, and 4 parts calcium carbonate.

[0083] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0084] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 4 parts of calcium carbonate and heat to 80°C while stirring.

[0085] S2. Add 0.15 parts of titanate coupling agent to the reaction vessel and continue stirring for 15 minutes;

[0086] S3. Filter the mixture in the reactor, then dry it at 120°C for 50 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0087] Example 8:

[0088] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 70 parts polyethylene, 45 parts magnesium hydroxide, 10 parts hydrotalcite, 3 parts phthalate coupling agent, and 6 parts calcium carbonate.

[0089] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0090] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 6 parts of calcium carbonate and heat to 70°C and stir.

[0091] S2. Add 3 parts of titanate coupling agent to the reaction vessel and continue stirring for 12 minutes;

[0092] S3. Filter the mixture in the reactor, then dry it at 110°C for 45 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0093] Example 9:

[0094] The magnesium-containing flame retardant comprises the following raw materials in parts by weight: 70 parts polyethylene, 45 parts magnesium hydroxide, 10 parts hydrotalcite, 3 parts phthalate coupling agent, and 6 parts calcium carbonate.

[0095] The preparation method of magnesium-containing flame retardants includes the following specific steps:

[0096] S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add 6 parts of calcium carbonate and heat to 80°C while stirring.

[0097] S2. Add 3 parts of titanate coupling agent to the reaction vessel and continue stirring for 15 minutes;

[0098] S3. Filter the mixture in the reactor, then dry it at 120°C for 50 minutes. After drying, sieve it to obtain the magnesium-containing flame retardant product.

[0099] Comparative Example 1:

[0100] The difference between Comparative Example 1 and Example 1 is that the magnesium hydroxide used in the raw materials is aluminum hydroxide.

[0101] Comparative Example 2:

[0102] The difference between Comparative Example 2 and Example 1 is that hydrotalcite was not used in the raw materials.

[0103] Comparative Example 3:

[0104] The difference between Comparative Example 3 and Example 1 is that calcium carbonate was not added during the mixing and stirring of the raw materials.

[0105] Comparative Example 4:

[0106] The difference between Comparative Example 4 and Example 1 is that no titanate coupling agent was added during the mixing and stirring of the raw materials.

[0107] The cables prepared in Examples 1-9 and Comparative Examples 1-4 were subjected to performance tests. The test methods are shown in Table 1.

[0108] Referring to the requirements of the national standard GB 31247-2014 "Classification of Flammability Performance of Cables and Optical Fibers":

[0109] Total calorific value: The total heat released when a unit mass of material is completely burned and all the water vapor in the combustion products condenses into water.

[0110] Flame spread: The maximum charring distance produced by the flame on the surface of the bundled cable, as determined by GB / T 31248.

[0111] Tensile strength: The maximum stress that the cable can withstand when subjected to tensile force, as tested according to GB / T 31248-2014.

[0112] Smoke density (minimum transmittance): Minimum transmittance measured according to GB / T 17651.2.

[0113] Table 1

[0114] Flames spread (m) Total calorific value released (MJ) Tensile strength (MPa) Smoke density (%) Example 1 1.8 3.5 18.5 30% Example 2 2.2 4.8 17.5 35% Example 3 2.7 5.7 15.6 42% Example 4 1.98 3.3 18.3 32% Example 5 2.05 3.2 18.2 33% Example 6 2.3 4.9 17.3 37% Example 7 2.5 5.2 16.8 39% Example 8 2.8 5.9 15.3 44% Example 9 3.0 6.2 14.8 47% Comparative Example 1 5.5 12.5 11.5 56% Comparative Example 2 3.8 8.5 13.8 50% Comparative Example 3 4.2 9.8 14.5 52% Comparative Example 4 4.8 10.3 12.8 54%

[0115] As shown in Table 1, comparing Example 1 with Examples 2 and 3, the addition of different amounts of polyethylene, magnesium hydroxide, hydrotalcite, titanate coupling agent, and calcium carbonate resulted in different final test performance data, with Example 1 exhibiting the best overall performance. Comparing Example 1 with Examples 4 and 5, Example 2 with Examples 6 and 7, and Example 3 with Examples 8 and 9, different stirring temperatures, stirring times, drying temperatures, and drying times affected the final test performance data, with Example 1 exhibiting the best overall performance. Comparing Example 1 with Comparative Examples 1, 2, 3, and 4, the use of magnesium hydroxide in the raw materials resulted in better test performance than the use of aluminum hydroxide, and the use of hydrotalcite, phthalate coupling agent, and calcium carbonate in the raw materials resulted in better test performance than the absence of these ingredients.

[0116] In summary, the performance tests of magnesium-containing flame retardants show low flame spread, low total calorific value release, high tensile strength, and low smoke density. At high temperatures, the chemical properties of magnesium in magnesium-containing flame retardants release moisture, which helps to reduce the combustion temperature and inhibit flame spread, resulting in strong fire resistance and high temperature resistance. Furthermore, magnesium-containing flame retardants are usually halogen-free, produce fewer harmful gases, and are more environmentally friendly. In fire conditions, magnesium-containing flame retardants can provide flame retardancy and heat insulation, enabling the cable to operate stably.

[0117] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A method for preparing a high-temperature resistant, fire-resistant flexible cable, characterized in that, The specific steps include the following: Step 1: The main body insulation component (702) is sprayed onto the outer wall of the main conductor (701) using an electrocoating device, and then the third outer sheath (703) is wrapped around the outer wall of the main body insulation component (702) using a twin-screw extruder to complete the processing of the main conductor (701); Step 2: The secondary conductor insulation component (802) is sprayed onto the outer wall of the secondary conductor (801) using an electrocoating device. Then, the fourth outer sheath (803) is wrapped around the outer wall of the secondary conductor insulation component (802) using a twin-screw extruder. Finally, the pressure-resistant sleeve (804) is wrapped around the outside of the fourth outer sheath (803) to complete the processing of the secondary conductor (801). Step 3: Use a hot air gun to heat and bond the cut control conductor shield (904) to the outer wall of the control conductor core (905). Use an electrocoating device to spray the control conductor insulation component (903) onto the outer wall of the control conductor shield (904). Then use a twin-screw extruder to wrap the fifth outer sheath (902) around the outside of multiple control conductor insulation components (903). Use a filling machine to fill the inside with a second filling layer (901) to ensure sealing. Step 4: Wrap the wrapping layer (5) around the outside of the main conductor assembly (7), multiple secondary conductor assemblies (8) and multiple control assemblies (9) using a wrapping machine, and fill the inside of it with the first filling layer (6) using a filling machine to ensure sealing. Then, extrude the inner sheath (4) around the outside of the wrapping layer (5) using a twin-screw extruder. Next, extrude the armor (3) around the outside of the inner sheath (4) using an armoring machine to ensure that the connection and port of the armor (3) are well sealed to prevent moisture and impurities from entering. Then, extrude the second outer sheath (2) around the outside of the armor (3) using a twin-screw extruder. Finally, extrude the first outer sheath (1) around the outside of the second outer sheath (2) using a twin-screw extruder to complete the cable preparation. The materials of the first outer sheath (1), the third outer sheath (703), the fourth outer sheath (803) and the fifth outer sheath (902) are all magnesium-containing flame retardants. The magnesium-containing flame retardants include the following raw materials in parts by weight: 60-70 parts of polyethylene, 35-45 parts of magnesium hydroxide, 6-10 parts of hydrotalcite, and 0.06-3 parts of titanate coupling agent. The preparation method of the magnesium-containing flame retardant includes the following specific steps: S1. Take polyethylene, magnesium hydroxide and hydrotalcite and put them into the reaction vessel and mix them evenly. Then slowly add calcium carbonate and heat and stir. S2. Add titanate coupling agent to the reactor and continue stirring; S3. Filter the mixture in the reactor, then dry it, and after drying, sieve it to obtain the magnesium-containing flame retardant product.

2. The method for preparing a high-temperature resistant fireproof flexible cable according to claim 1, characterized in that, The amount of calcium carbonate added in S1 is 3-5 parts, and the temperature for heating and stirring is 60-80℃.

3. The method for preparing a high-temperature resistant fire-resistant flexible cable according to claim 1, characterized in that, The stirring time in S2 is 10-15 minutes.

4. The method for preparing a high-temperature resistant fireproof flexible cable according to claim 1, characterized in that, The drying temperature in S3 is 100~120℃, and the drying time is 40~50min.

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