High-shielding-property flame-retardant fire-resistant control cable and preparation method thereof

Abstract

The invention relates to the technical field of cables, and discloses a high-shielding flame-retardant fire-resistant control cable and a preparation method thereof. The high-shielding-property flame-retardant fire-resistant control cable comprises a wire, a shielding layer, an insulating layer and a flame-retardant fire-resistant polyethylene sheath material, the flame-retardant fire-resistant polyethylene sheath material comprises sodium carboxymethyl cellulose, hyperbranched polyphosphate, polyethylene resin and an antioxidant. The hyperbranched polyphosphate contains a large number of flame-retardant phosphate groups, the phosphate groups are combusted to generate phosphoric acid substances, cellulose can be promoted to be dehydrated into carbon, a carbon barrier layer is formed on the surface of the polyethylene sheath material, the limit oxygen index and the UL-94 grade of the sheath material can be remarkably improved without adding aluminum hydroxide and other inorganic flame retardants, and the flame-retardant performance of the sheath material is improved. And the flame retardant performance is excellent, and the cable has good practical application in the aspects of flame-retardant and fire-resistant control cables and the like.

Description

Technical Field

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

[0002] Cables are mainly composed of sheath material, insulation layer, shielding layer, and conductors. The sheath material primarily serves functions such as flame retardancy, corrosion resistance, and UV protection. Common cable sheath materials include polyethylene and polyvinyl chloride. Polyethylene sheath material has good flexibility, corrosion resistance, and aging resistance; however, it is flammable and has poor fire resistance, which limits its practical application.

[0003] Adding flame retardants to polyethylene sheathing materials can improve their flame retardant and fire-resistant properties. Compared with inorganic flame retardants such as aluminum hydroxide, organic halogen-free flame retardants are environmentally friendly, have good flame retardant properties, require small amounts, and have good compatibility with the polymer matrix, making them widely used. Patent CN114933755B discloses a low-shrinkage, low-smoke halogen-free cable material and its preparation method. It involves adding hyperbranched siloxanes, a primary flame retardant, and a secondary flame retardant to low-density polyethylene to work together to enhance flame retardancy. The resulting cable material exhibits good flame retardant properties. However, this patent requires the additional addition of inorganic flame retardants such as aluminum hydroxide, making the flame retardant system relatively complex. Summary of the Invention

[0004] The technical problem solved by this invention is to address the issue of poor flame retardancy in polyethylene cable sheath materials.

[0005] The technical solution of the present invention: a high-shield flame-retardant and fire-resistant control cable, comprising a conductor, a shielding layer, an insulation layer, and a flame-retardant and fire-resistant polyethylene sheath; The conductors include copper conductors and aluminum conductors. The shielding layer includes copper mesh and copper foil. The insulation layer includes cross-linked polyethylene insulation. The preparation methods for flame-retardant and fire-resistant polyethylene sheathing materials include: (1) Add N-methyldiethanolamine to water, add concentrated hydrochloric acid dropwise for neutralization, stir and add dodecyl glycidyl ether and ethanol. After reaction, heat to volatilize, cool and crystallize to obtain N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride.

[0006] (2) Add N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride and triethylamine to tetrahydrofuran, add phenyl dichloride phosphate dropwise in an ice-water bath, distill under reduced pressure after reaction, wash the product with ethanol, dry, and obtain hyperbranched polyphosphate ester.

[0007] (3) Add sodium carboxymethyl cellulose and hyperbranched polyphosphate to water, heat and stir, dry and remove water, mix the material with polyethylene resin and antioxidant, place it in a twin-screw extruder for extrusion, granulate, and then hot press it through a flat vulcanizing machine to obtain flame-retardant and fire-resistant polyethylene sheath material.

[0008] Preferably, the ratio of N-methyldiethanolamine to dodecyl glycidyl ether in (1) is (1-1.1) mol: 1 mol.

[0009] Preferably, the reaction temperature in (1) is 60-80℃ and the reaction time is 6-10h.

[0010] Preferably, in (2), the ratio of N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride, triethylamine, and phenyl dichloride phosphate is 1 mol: (3-3.6) mol: (1.4-1.6) mol.

[0011] Preferably, in (2), the reaction temperature is 50-65℃ and the reaction time is 8-12h.

[0012] Preferably, the heating and stirring temperature in (3) is 50-80℃ and the time is 1-2h.

[0013] Preferably, the ratio of sodium carboxymethyl cellulose, hyperbranched polyphosphate, polyethylene resin and antioxidant in (3) is (5-15):(10-25):100:(0.2-0.5).

[0014] Preferably, in (3), the temperature of each section of the twin-screw extruder is 120-185℃ and the screw speed is 40-80r / min.

[0015] Preferably, the temperature of the flat vulcanizing machine in (3) is 180-190℃ and the pressure is 10-15MPa.

[0016] The beneficial technical effects of this invention are as follows: This invention involves the hyperbranching polymerization of N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride containing three hydroxyl groups with phenyl phosphate dichloride to obtain hyperbranched polyphosphate ester. This hyperbranched polyphosphate ester is then added to polyethylene resin to obtain a flame-retardant and fire-resistant polyethylene sheath material. This hyperbranched polyphosphate ester contains quaternary ammonium salt cations, which form electrostatic interactions with the sodium carboxylate anions of sodium carboxymethyl cellulose, thereby coating the surface of sodium carboxymethyl cellulose with the hyperbranched polyphosphate ester. The hyperbranched polyphosphate ester contains long-chain alkanes, exhibiting excellent compatibility with polyethylene resin. The coating effect of the hyperbranched polyphosphate ester improves the compatibility between sodium carboxymethyl cellulose and polyethylene resin, allowing the polyethylene sheath material to maintain good tensile properties.

[0017] The hyperbranched polyphosphate of the present invention has a hyperbranched dendritic structure, which forms a physical cross-linking effect with the polyethylene molecular chain, thus having a good toughening and reinforcing effect on polyethylene and improving the tensile strength and elongation at break of the polyethylene sheath material.

[0018] The hyperbranched polyphosphate of this invention contains a large number of flame-retardant phosphate groups. The combustion of the phosphate groups generates phosphoric acid, which can promote the dehydration of cellulose into char and form a char barrier layer on the surface of the polyethylene sheath material. Without the addition of inorganic flame retardants such as aluminum hydroxide, it can significantly improve the limiting oxygen index and UL-94 rating of the sheath material. It has excellent flame retardant properties and has good practical applications in flame-retardant and fire-resistant control cables. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0020] Example 1: A high-shielding flame-retardant and fire-resistant control cable, the cable comprising a flame-retardant and fire-resistant polyethylene sheath.

[0021] The preparation method of flame-retardant and fire-resistant polyethylene sheath material is as follows: (1) Add 0.2 mol N-methyldiethanolamine to 200 mL of water, add 16.7 mL of concentrated hydrochloric acid with a concentration of 12 mol / L for neutralization, stir, add 0.2 mol dodecyl glycidyl ether and 300 mL of ethanol, heat to 80 °C, stir and reflux for 6 h, heat to volatilize, cool and crystallize to obtain N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride.

[0022] (2) Add 0.3 mol N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride and 0.6 mol triethylamine to 1 L of tetrahydrofuran, add 0.2 mol phenyl phosphate dichloride dropwise in an ice-water bath, heat to 60 °C, stir and reflux for 12 h, wash the product with ethanol after vacuum distillation, and dry to obtain hyperbranched polyphosphate.

[0023] (3) Add 50g sodium carboxymethyl cellulose and 100g hyperbranched polyphosphate to 2L of water, heat to 60℃, stir for 1h, dry and remove water, mix the material with 1kg polyethylene resin (model Dow DFDG-6059) and 2g antioxidant 1010, place in a twin-screw extruder for extrusion, the temperature of each section is 120℃, 150℃, 170℃, 185℃ and 180℃, the screw speed is 40r / min, pelletize, and then hot press through a flat vulcanizing machine at a temperature of 180℃ and a pressure of 15MPa to obtain flame-retardant and fire-resistant polyethylene sheath material.

[0024] Example 2: A high-shielding flame-retardant and fire-resistant control cable, the cable comprising a flame-retardant and fire-resistant polyethylene sheath.

[0025] The preparation method of flame-retardant and fire-resistant polyethylene sheath material is as follows: (1) Add 0.22 mol N-methyldiethanolamine to 200 mL of water, add 18.4 mL of concentrated hydrochloric acid with a concentration of 12 mol / L for neutralization, stir, add 0.2 mol dodecyl glycidyl ether and 350 mL of ethanol, heat to 60 °C, stir and reflux for 10 h, heat to volatilize, cool and crystallize to obtain N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride.

[0026] (2) Add 0.28 mol N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride and 0.6 mol triethylamine to 1 L of tetrahydrofuran, add 0.2 mol phenyl phosphate dichloride dropwise in an ice-water bath, heat to 50 °C, stir and reflux for 12 h, wash the product with ethanol after vacuum distillation, and dry to obtain hyperbranched polyphosphate.

[0027] (3) Add 100g sodium carboxymethyl cellulose and 180g hyperbranched polyphosphate to 3L of water, heat to 50℃, stir for 2h, dry and remove water, mix the material with 1kg polyethylene resin and 5g antioxidant 1010, place it in a twin-screw extruder for extrusion, the temperature of each section is 120℃, 150℃, 170℃, 185℃ and 180℃, the screw speed is 80r / min, pelletize, and then hot press through a flat vulcanizing machine at a temperature of 190℃ and a pressure of 10MPa to obtain flame-retardant and fire-resistant polyethylene sheath material.

[0028] Example 3: A high-shield flame-retardant and fire-resistant control cable, the cable comprising a flame-retardant and fire-resistant polyethylene sheath.

[0029] The preparation method of flame-retardant and fire-resistant polyethylene sheath material is as follows: (1) Prepare N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride according to the method of Example 1.

[0030] (2) Add 0.32 mol N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride and 0.72 mol triethylamine to 1.2 L tetrahydrofuran, add 0.2 mol phenyl phosphate dichloride dropwise in an ice-water bath, heat to 65 °C, stir and reflux for 8 h, wash the product with ethanol after vacuum distillation, and dry to obtain hyperbranched polyphosphate.

[0031] (3) Add 150g sodium carboxymethyl cellulose and 250g hyperbranched polyphosphate to 4L of water, heat to 80℃, stir for 1.5h, dry and remove water, mix the material with 1kg polyethylene resin and 4g antioxidant 1010, place it in a twin-screw extruder for extrusion, the temperature of each section is 120℃, 150℃, 170℃, 185℃ and 180℃, the screw speed is 80r / min, pelletize, and then hot press through a flat vulcanizing machine at a temperature of 185℃ and a pressure of 15MPa to obtain flame-retardant and fire-resistant polyethylene sheath material.

[0032] Comparative Example 1: A control cable comprising a polyethylene sheath.

[0033] The preparation method of polyethylene sheath material is as follows: (1) Mix 50g sodium carboxymethyl cellulose, 1kg polyethylene resin and 2g antioxidant 1010, and extrude them in a twin-screw extruder. The temperatures of each section are 120℃, 150℃, 170℃, 185℃ and 180℃, and the screw speed is 40r / min. The mixture is then pelletized and hot-pressed through a flat vulcanizing machine at a temperature of 180℃ and a pressure of 15MPa to obtain polyethylene sheath material.

[0034] Comparative Example 2: A control cable comprising a polyethylene sheath.

[0035] The preparation method of polyethylene sheath material is as follows: (1) Prepare N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride according to the method of Example 1.

[0036] (2) Add 50g sodium carboxymethyl cellulose and 100g N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride to 2L of water, heat to 60℃, stir for 1h, dry to remove water, mix the material with 1kg polyethylene resin and 2g antioxidant 1010, place in a twin-screw extruder for extrusion, the temperature of each section is 120℃, 150℃, 170℃, 185℃ and 180℃, the screw speed is 40r / min, pelletize, and then hot press through a flat vulcanizing machine at 180℃ and 15MPa to obtain polyethylene sheath material.

[0037] Comparative Example 3: A control cable comprising a polyethylene sheath.

[0038] The preparation method of polyethylene sheath material is as follows: (1) Add 0.3 mol triethanolamine and 0.6 mol triethylamine to 1 L tetrahydrofuran, add 0.2 mol phenyl phosphate dichloride dropwise in an ice-water bath, heat to 60 °C, stir and reflux for 12 h, wash the product with ethanol after vacuum distillation, and dry to obtain hyperbranched polyphosphate.

[0039] (2) Add 50g sodium carboxymethyl cellulose and 100g hyperbranched polyphosphate to 2L of water, heat to 60℃, stir for 1h, dry to remove water, mix the material with 1kg polyethylene resin and 2g antioxidant 1010, place in a twin-screw extruder for extrusion, the temperature of each section is 120℃, 150℃, 170℃, 185℃ and 180℃, the screw speed is 40r / min, pelletize, and then hot press through a flat vulcanizing machine at 180℃ and 15MPa to obtain polyethylene sheath material.

[0040] Comparative Example 4: A control cable comprising a polyethylene sheath.

[0041] The preparation method of polyethylene sheath material is as follows: (1) Add 0.2 mol N,N-dimethylethanolamine to 200 mL of water, add 16.7 mL of concentrated hydrochloric acid (12 mol / L) dropwise for neutralization, stir, add 0.2 mol dodecyl glycidyl ether and 300 mL of ethanol, heat to 80 °C, stir, reflux for 6 h, heat to volatilize, cool and crystallize to obtain N-(2-hydroxyethyl)-N,N-bis(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride, with the structural formula: .

[0042] (2) Add 0.3 mol N-(2-hydroxyethyl)-N,N-bis(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride and 0.6 mol triethylamine to 1 L of tetrahydrofuran, add 0.3 mol phenyl phosphate dichloride dropwise in an ice-water bath, heat to 60 °C, stir and reflux for 12 h, wash the product with ethanol after vacuum distillation, and dry to obtain polyphosphate.

[0043] (3) Add 50g sodium carboxymethyl cellulose and 100g polyphosphate to 2L of water, heat to 60℃, stir for 1h, dry and remove water, mix the material with 1kg polyethylene resin and 2g antioxidant 1010, place it in a twin-screw extruder for extrusion, the temperature of each section is 120℃, 150℃, 170℃, 185℃ and 180℃, the screw speed is 40r / min, pelletize, and then hot press through a flat vulcanizing machine at a temperature of 180℃ and a pressure of 15MPa to obtain polyethylene sheath material.

[0044] The flame retardant properties of the polyethylene sheath material were tested according to standard GB / T 2406.1-2008 and UL-94 method. The tensile properties were tested according to standard GB / T 1040.1-2018.

[0045] Table 1 Performance of Polyethylene Sheathing Material

[0046] Compared with Comparative Example 1, the polyethylene cable sheathing materials of Examples 1-3 contain hyperbranched polyphosphate, which contains quaternary ammonium salt cations that form electrostatic interactions with the sodium carboxylate anions of sodium carboxymethyl cellulose, thereby coating the surface of sodium carboxymethyl cellulose with hyperbranched polyphosphate. Hyperbranched polyphosphate contains long-chain alkanes and has good compatibility with polyethylene resin. Under the coating effect of hyperbranched polyphosphate, the compatibility between sodium carboxymethyl cellulose and polyethylene resin is improved, allowing the polyethylene sheathing material to maintain good tensile properties. Furthermore, the hyperbranched polyphosphate has a hyperbranched dendritic structure that forms physical cross-linking with the polyethylene molecular chains, providing good toughening and reinforcing effects on polyethylene and improving the tensile strength and elongation at break of the polyethylene sheathing material. Hyperbranched polyphosphate contains a large number of flame-retardant phosphate groups. The combustion of phosphate groups generates phosphoric acid, which can promote the dehydration of cellulose into char and form a char barrier layer on the surface of polyethylene sheath material. This significantly improves the flame-retardant performance of the sheath material, has a higher limiting oxygen index, and achieves a UL-94 rating of V-1 to V-0.

[0047] N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride in Comparative Example 2 is a small molecule compound that does not have a hyperbranched dendritic structure. It is difficult to toughen and reinforce polyethylene, resulting in lower tensile strength and elongation at break than in Example 1, and poor flame retardancy of polyethylene.

[0048] The triethanolamine of Comparative Example 3 and the hyperbranched polyphosphate ester prepared therefrom do not contain quaternary ammonium salt cations and cannot form electrostatic interactions with sodium carboxymethyl cellulose, thus failing to improve the compatibility between cellulose and polyethylene, resulting in lower tensile strength and elongation at break than in Example 1.

[0049] The N-(2-hydroxyethyl)-N,N-bis(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride in Comparative Example 4 contains only two hydroxyl groups. The polyphosphate ester prepared is a linear molecular chain and does not have a hyperbranched dendritic structure. It is difficult to toughen and reinforce polyethylene, resulting in lower tensile strength and elongation at break than in Example 1.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be within the scope of protection of the pending claims of the present invention.

Claims

1. A highly shielded, flame-retardant, and fire-resistant control cable, characterized in that, The high-shield flame-retardant and fire-resistant control cable includes a conductor, a shielding layer, an insulation layer, and a flame-retardant and fire-resistant polyethylene sheath. The preparation method of the flame-retardant and fire-resistant polyethylene sheath material includes: adding sodium carboxymethyl cellulose and hyperbranched polyphosphate to water, heating and stirring, drying to remove water, mixing the material with polyethylene resin and antioxidant, extruding in a twin-screw extruder, pelletizing, and then hot-pressing through a flat vulcanizing machine to obtain the flame-retardant and fire-resistant polyethylene sheath material.

2. The high-shield flame-retardant and fire-resistant control cable according to claim 1, characterized in that, The conductors include copper conductors and aluminum conductors; the shielding layer includes copper mesh and copper foil; and the insulation layer includes cross-linked polyethylene insulation.

3. The high-shield flame-retardant and fire-resistant control cable according to claim 1, characterized in that, The heating and stirring temperature is 50-80℃, and the time is 1-2 hours.

4. The high-shield flame-retardant and fire-resistant control cable according to claim 1, characterized in that, The ratio of sodium carboxymethyl cellulose, hyperbranched polyphosphate, polyethylene resin, and antioxidant is (5-15):(10-25):100:(0.2-0.5).

5. The high-shield flame-retardant and fire-resistant control cable according to claim 1, characterized in that, The temperature of each section of the twin-screw extruder is 120-185℃, and the screw speed is 40-80 r / min.

6. The high-shield flame-retardant and fire-resistant control cable according to claim 1, characterized in that, The temperature of the flat vulcanizing machine is 180-190℃, and the pressure is 10-15MPa.

7. The high-shield flame-retardant and fire-resistant control cable according to claim 1, characterized in that, The preparation method of the hyperbranched polyphosphate is as follows: (1) Add N-methyldiethanolamine to water, add concentrated hydrochloric acid dropwise for neutralization, stir, add dodecyl glycidyl ether and ethanol, heat to 60-80℃, stir and reflux for 6-10h, heat to volatilize, cool and crystallize to obtain N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride; (2) Add N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride and triethylamine to tetrahydrofuran, add phenyl dichloride phosphate dropwise in an ice-water bath, heat to 50-65℃, stir and reflux for 8-12 hours, wash the product under reduced pressure, and dry to obtain hyperbranched polyphosphate ester.

8. The high-shield flame-retardant and fire-resistant control cable according to claim 7, characterized in that, The ratio of N-methyldiethanolamine to dodecyl glycidyl ether is (1-1.1) mol: 1 mol.

9. The high-shield flame-retardant and fire-resistant control cable according to claim 7, characterized in that, The ratio of N,N-bis(2-hydroxyethyl)-N-(2-methyl)-N-(3-dodecyloxy-2-hydroxy)ammonium chloride, triethylamine, and phenyl dichloride phosphate is 1 mol: (3-3.6) mol: (1.4-1.6) mol.

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