A high temperature resistant and twist resistant cable

Abstract

The invention discloses a high-temperature resistant and twist-resistant cable, which belongs to the technical field of cable processing and is used to solve the technical problem in the prior art that the high-temperature resistance, mechanical properties, twist-resistant properties and flame-retardant properties of cables need to be further improved. The invention comprises the following steps: adding modified polyurethane, modified flame retardant, modified sepiolite and auxiliary additives into a twin-screw extruder, and melt-extruding them on the outside of a wrapping layer to obtain a high-temperature resistant and twist-resistant cable. The invention uses modified polyurethane as a base material, modified flame retardant and modified sepiolite as reinforcing materials, and auxiliary additives as auxiliary agents to prepare a high-temperature resistant and twist-resistant cable, which not only effectively improves the twist-resistant and high-temperature resistance of the cable, but also improves its flame-retardant properties.

Description

Technical Field

[0001] The invention relates to the technical field of cable processing, in particular to a high-temperature resistant and twist-resistant cable. Background Art

[0002] Wires and cables, as carriers of electric energy transmission, play an indispensable and important role. The insulation layer on the outside of wires and cables protects the metal conductors and prevents short circuits and leakage. Common insulation layer base materials include polyvinyl chloride, polyethylene, polyurethane, and ethylene-vinyl acetate copolymer. These insulation materials have good electrical insulation and wear resistance, which can effectively protect the metal conductors and extend the service life of cable materials. However, these insulation materials have the disadvantages of being not resistant to high temperatures and being flammable. When the conductor has poor conductivity or the insulation layer is aged or damaged, the conductor is exposed, which may cause local high temperature, sparks, and even fire, resulting in casualties and economic property losses.

[0003] In addition, in some industrial applications, cables are often installed on equipment such as robotic arms, conveyor belts, and cranes. During the movement of these devices, cables are often subjected to multiple stresses such as torsion, stretching, and bending. If the cable's torsion resistance is insufficient, long-term torsion will cause wear of the cable outer sheath, damage to the conductor, or aging of the insulation, ultimately affecting the transmission stability of power or signals.

[0004] In the prior art, in order to improve the high-temperature resistance of cables, it is a common method to add heat-resistant flame retardants when manufacturing cable protective sheaths. However, these flame retardants are usually difficult to be compatible with other fillers used in preparing cables, which increases the brittleness of the material and makes the cable more likely to crack or break when bent, stretched or twisted. In addition, organic heat-resistant flame retardants will gradually decompose or volatilize due to high temperature, ultraviolet radiation or long-term use of cables, resulting in a gradual weakening of their flame retardant effect and difficulty in providing long-term and stable flame retardant protection. When inorganic materials with high-temperature resistant flame retardant properties are added to work synergistically with organic flame retardants, the mechanical properties of the cable will be poor due to interface incompatibility, thereby affecting the high-temperature flame retardant effect of the cable. Summary of the Invention

[0005] The object of the present invention is to provide a high-temperature resistant and torsion-resistant cable, which is used to solve the technical problem in the prior art that the high-temperature resistance, mechanical properties, torsion resistance and flame retardancy of cables need to be further improved.

[0006] The object of the present invention can be achieved by the following technical solution: A high temperature resistant and twist resistant cable comprises a plurality of wire cores, an insulating rubber layer, a wrapping layer and a sheath layer arranged in sequence from the inside to the outside;

[0007] The wire core includes a conductor composed of a plurality of mutually twisted metal alloy wires and an insulating rubber layer covering the outside of the conductor;

[0008] The wrapping layer is obtained by wrapping the wrapping tape around the outside of several wire cores;

[0009] The sheath layer comprises the following components in parts by weight: 20-30 parts of modified polyurethane, 5-10 parts of modified flame retardant, 15-20 parts of modified sepiolite and 2-4 parts of auxiliary additives.

[0010] Furthermore, the metal alloy wire is a copper-tin alloy wire, the insulating rubber layer is one or more of styrene-butadiene rubber, ethylene-propylene rubber, and chloroprene rubber, and the wrapping tape is one or more of polyester tape and aluminum metal tape.

[0011] Furthermore, the preparation method of the sheath layer is: adding modified polyurethane, modified flame retardant, modified sepiolite and auxiliary additives into a twin-screw extruder, and melt-extruding them on the outside of the wrapping layer to form the sheath layer outside the wrapping layer.

[0012] Furthermore, the auxiliary additives are composed of a lubricant, an antioxidant, and a filler in a weight ratio of 1:1:2, the lubricant is one or more of barium stearate and silicone oil, the antioxidant is one or more of antioxidant 6PPD, antioxidant MB, and antioxidant MBI, and the filler is one or more of carbon black, montmorillonite, and calcium carbonate; the temperatures of the eight temperature zones of the twin-screw extruder from the feed port to the discharge port are 150°C, 150°C, 155°C, 155°C, 165°C, 165°C, 170°C, and 170°C, respectively; the main engine speed of the twin-screw extruder is 60-110rpm, and the pressure is 120bar.

[0013] Furthermore, the preparation method of the modified polyurethane comprises the following steps:

[0014] A1. Place octamethylcyclotetrasiloxane, sodium hydroxide solution and toluene in a reactor protected by nitrogen atmosphere, heat to 85-105° C., keep warm for 1-2 hours, and post-treat to obtain hydroxyl-terminated polysiloxane;

[0015] The preparation reaction formula of hydroxyl-terminated polysiloxane is:

[0016]

[0017] The preparation reaction principle of hydroxyl-terminated polysiloxane is:

[0018] In the alkaline environment of sodium hydroxide, the silicon-oxygen bond of octamethylcyclotetrasiloxane is catalyzed by sodium hydroxide, undergoing a ring-opening reaction to generate an active silanol group. The generated terminal hydroxyl intermediate further forms a polysiloxane chain through a condensation polymerization reaction. The deionized water in the sodium hydroxide solution provides hydroxyl groups to end the polysiloxane chain to obtain a terminal hydroxyl polysiloxane.

[0019] A2. Place hydroxy-terminated polysiloxane, 1,4-butanediol, dibutyltin dilaurate, toluene, and diphenylmethane diisocyanate in a reactor protected by a nitrogen atmosphere, heat to 75-85° C., and perform post-treatment to obtain a modified polyurethane precursor;

[0020] The preparation reaction formula of the modified polyurethane precursor is:

[0021]

[0022] Where: , .

[0023] The preparation reaction principle of modified polyurethane precursor is:

[0024] Under the catalysis of dibutyltin dilaurate and high temperature, the hydroxyl groups in the terminal hydroxyl polysiloxane and 1,4-butanediol react with diphenylmethane diisocyanate to prepare an isocyanate-modified modified polyurethane precursor.

[0025] A3. Place the modified polyurethane precursor, KH-550 and toluene in a reactor, heat to 90-110°C, keep the temperature for reaction for 1-2 hours, and post-treat to obtain the modified polyurethane.

[0026] The preparation reaction formula of modified polyurethane is:

[0027]

[0028] Where:

[0029]

[0030] The preparation reaction principle of modified polyurethane is:

[0031] During the reaction, the amino group in KH-550 acts as a nucleophilic reagent to attack the isocyanate end capping group in the modified polyurethane precursor to prepare a modified polyurethane modified with a silane coupling agent.

[0032] Furthermore, in step A1, the concentration of the sodium hydroxide solution is 10-15wt%, the amount ratio of the octamethylcyclotetrasiloxane, the sodium hydroxide solution and the toluene is 5-10g:2-4mL:60-90mL, and the post-treatment step comprises: after the reaction is completed, the reaction system is cooled to room temperature, ethyl acetate and pure water are added to the reaction solution, washed 1-2 times, and the organic phase is transferred to a rotary evaporator at a temperature of 40-50°C, and rotated until no liquid is extracted to obtain a terminal hydroxyl polysiloxane; in step A2, the molar ratio of the diphenylmethane diisocyanate is 2 times the molar amount of the hydroxyl group in the terminal hydroxyl polysiloxane and 1,4-butanediol, and the terminal hydroxyl polysiloxane, 1,4-butanediol, The amount ratio of alcohol, dibutyltin dilaurate and toluene is 5-10g:4-6g:0.1-1.5g:100-120mL. The post-processing step includes: after the reaction is completed, the reaction system is cooled to room temperature, ethanol is added to the reaction solution, the reactor is heated to 110-120°C, and vacuum distillation is performed until no liquid is recovered, thereby obtaining a modified polyurethane precursor. In step A3, the amount ratio of the modified polyurethane precursor, KH-550 and toluene is 8-13g:2-3g:150-200mL. The post-processing step includes: after the reaction is completed, ethanol is added to the reaction solution, the reactor is heated to 100-110°C, and vacuum distillation is performed until no liquid is recovered, thereby obtaining a modified polyurethane.

[0033] Furthermore, the preparation method of the modified flame retardant comprises the following steps:

[0034] B1. Place p-methylphenylethylamine, 2-phenylpropanal and ethanol in a reaction kettle, heat to 80-90°C, stir for 4-6 hours, and post-treat to obtain intermediate I;

[0035] The preparation reaction formula of intermediate I is:

[0036]

[0037] Mass spectrometry analysis data of intermediate Ⅰ, m / z: 251.14 (100.0%), 252.14 (19.7%), 253.14 (1.9%).

[0038] The reaction principle for the preparation of intermediate I is:

[0039] The amino nitrogen atom in p-methylphenylethylamine carries a lone electron pair and, as a nucleophile, can attack the aldehyde carbon atom in 2-phenylpropanal to form an intermediate alcoholamine, which is further dehydrated to obtain an intermediate I containing an imine structure.

[0040] B2. Place intermediate I, ethanol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution in a reaction kettle, heat to 80-90°C, keep warm for 8-10 hours, and post-treat to obtain intermediate II;

[0041] The preparation reaction formula of intermediate II is:

[0042]

[0043] Mass spectrometry analysis data of intermediate II, m / z: 467.23 (100.0%), 468.23 (32.8%), 469.24 (5.6%).

[0044] The reaction principle for the preparation of intermediate II is:

[0045] During the reaction, the imino group in intermediate I acts as a nucleophile to attack the electrophilic phosphorus atom in 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, resulting in a nucleophilic addition reaction to obtain intermediate II.

[0046] B3. Place intermediate II, 3-isocyanatepropyltriethoxysilane, triethylamine and toluene in a reaction kettle, heat to 100-120°C, keep warm and react for 4-6 hours, and post-treat to obtain a modified flame retardant.

[0047] The preparation reaction formula of the modified flame retardant is:

[0048]

[0049] Mass spectrometry analysis data of modified flame retardant, m / z: 728.37 (100.0%), 729.37 (50.2%), 730.38 (11.2%), 730.37 (6.0%), 731.38 (2.5%), 731.37 (1.7%).

[0050] The preparation reaction principle of modified flame retardant is:

[0051] During the reaction, the amino nitrogen atom with a lone electron pair in intermediate II attacks the carbon atom in isocyanate, thereby breaking the C=N double bond to prepare an isocyanate-modified modified flame retardant.

[0052] Further, in step B1, the amount ratio of p-methylphenylethylamine, 2-phenylpropanal and ethanol is 5-7g:4-6g:100-150mL, and the post-treatment step comprises: after the reaction is completed, filtering, washing the filter cake with ethanol 1-2 times, transferring it to a drying oven at a temperature of 50-60°C, and drying it to constant weight to obtain intermediate I; in step B2, the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution is composed of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and ethanol in a ratio of 10-12g:40-50mL, and the intermediate I, ethanol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene- The amount ratio of 10-oxide solution is 10-12g:100-120mL:10-15mL, and the post-processing step includes: after the reaction is completed, the reaction temperature is cooled to room temperature, filtered, the filter cake is washed with ethanol 1-2 times, transferred to a drying oven at a temperature of 50-60°C, and dried to constant weight to obtain intermediate II; in step B3, the amount ratio of intermediate II, 3-isocyanatepropyltriethoxysilane, triethylamine and toluene is 12-15g:2-3g:1.5-2g:200-250mL, and the post-processing step includes: after the reaction is completed, ethanol is added to the reaction solution, the temperature is raised to 100-120°C, and reduced pressure distillation is performed until no liquid is recovered to obtain a modified flame retardant.

[0053] Furthermore, the preparation method of the modified sepiolite is as follows: placing sepiolite and dilute nitric acid in a reaction kettle, heating to 20-30° C., stirring at this temperature for 12-16 hours, filtering, washing, drying, and ball milling to obtain the modified sepiolite.

[0054] The preparation reaction principle of modified sepiolite is:

[0055] During the preparation process, dilute nitric acid reacts chemically with various metal silicate minerals in sepiolite to generate soluble chlorides to obtain modified sepiolite.

[0056] Furthermore, the concentration of the dilute nitric acid is 0.5-1.5 mol / mL, the usage ratio of the sepiolite and the dilute nitric acid is 10-20 g:100-150 mL, and the ball milling operation steps include: adding the dried solid and ceramic ball mixture into the ball milling tank of a planetary ball mill, and ball milling for 30-40 minutes to obtain the modified sepiolite.

[0057] Furthermore, the ceramic balls are 30 mm, 40 mm and 50 mm in a mass ratio of 1:1:1, the filling rate is set to 50%, and the rotation speed is set to 35 r / min.

[0058] The present invention has the following beneficial effects:

[0059] 1. A high-temperature resistant and torsion-resistant cable prepared by the present invention uses modified polyurethane as a base material, a modified flame retardant and modified sepiolite as reinforcing materials, and auxiliary additives as auxiliary agents to prepare a high-temperature resistant and torsion-resistant cable. Terminated hydroxyl polysiloxane, 1,4-butanediol, and diphenylmethane diisocyanate are prepared into a modified polyurethane precursor with silicon-oxygen bonds and phenyl groups through polymerization, which is further cross-linked with a silane coupling agent to prepare a modified polyurethane, thereby improving the mechanical strength, high-temperature resistance, and torsion resistance of the cable. The flame retardant properties of the cable sheath layer are further improved by preparing a modified flame retardant containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. The sepiolite itself contains a silicon-oxygen structure. After being treated with dilute hydrochloric acid, the number of silicon-oxygen bonds increases, thereby improving its flame retardant properties.

[0060] 2. In the process of preparing a high-temperature resistant and twist-resistant cable, the present invention adds a modified flame retardant containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. The flame retardant contains a large amount of phosphorus and oxygen elements. These elements can release phosphoric acid or phosphorus oxide under high temperature or fire conditions. The phosphorus atoms inhibit the generation of combustible gas through catalytic reaction and delay the occurrence of thermal decomposition reaction. Phosphate can reduce the temperature of the fire source through endothermic reaction and prevent further combustion of the material. Due to the unique effect of phosphorus, the protective sheath of the cable can form a flame retardant when exposed to high temperature. The hard carbonized layer further isolates oxygen, reduces the continuous effect of flame on the material, and reduces the generation of toxic gases. The intermediate II is modified with 3-isocyanatepropyltriethoxysilane to obtain a modified flame retardant modified with triethylsiloxane. When the modified sepiolite and modified polyurethane are used to prepare cable protective sheaths, chemical bonds can be formed to promote the interface bonding between the materials, enhance their compatibility, avoid interface defects or falling off caused by poor compatibility, and improve the cable's anti-torsion performance, mechanical properties, flame retardancy, and high temperature resistance.

[0061] 3. In the process of preparing a high-temperature resistant and torsion-resistant cable, the present invention acidifies and modifies sepiolite. The structure of sepiolite itself contains silicon-oxygen tetrahedrons and is rich in natural fibrous minerals such as Mg and Si, which are non-halogen flame-retardant elements. It has a low thermal conductivity and is resistant to high temperatures. It can form a protective carbonized layer in the event of a fire. This carbonized layer can effectively isolate oxygen, delay the spread of flames, and improve the high-temperature resistance and flame-retardant properties of the cable. After treatment with dilute nitric acid, impurities on the surface of the sepiolite are removed, the original pores are expanded, and a more developed multi-level pore structure is formed. , the specific surface area is increased, more silanol groups are introduced, the active sites are increased, and after ball milling, the particle size of the modified sepiolite is uniform, which improves its dispersibility in modified polyurethane, modified flame retardant and auxiliary additives. Sepiolite is a low-density mineral. Adding it to the cable sheath can reduce the total weight of the sheath layer and reduce the concentration of internal stress during cable application, thereby improving the cable's anti-twisting performance. The silanol groups on its surface react with the silicon-oxygen bonds in the modified polyurethane and modified flame retardant to form chemical crosslinks through condensation reactions, further improving the mechanical properties of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0063] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention;

[0064] In the figure: 1. Wire core; 2. Insulating rubber layer; 3. Wrapping layer; 4. Sheath layer. DETAILED DESCRIPTION

[0065] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0066] Example 1

[0067] A high-temperature resistant and twist-resistant cable according to this embodiment includes the following steps:

[0068] S1. Preparation of modified polyurethane

[0069] Weigh: 50 g of octamethylcyclotetrasiloxane, 20 mL of 10 wt% sodium hydroxide solution, and 600 mL of toluene are placed in a reactor protected by a nitrogen atmosphere, heated to 85°C, and kept warm for 1 hour. After the reaction is completed, the reaction system is cooled to room temperature, ethyl acetate and pure water are added to the reaction solution, and washed twice. The organic phase is transferred to a rotary evaporator at a temperature of 40°C and rotated until no liquid is recovered to obtain a hydroxy-terminated polysiloxane;

[0070] Weigh: 50 g of terminal hydroxyl polysiloxane, 40 g of 1,4-butanediol, 1 g of dibutyltin dilaurate, and 1 L of toluene, place them in a reactor protected by a nitrogen atmosphere and stir, weigh diphenylmethane diisocyanate at twice the molar amount of the hydroxyl group in the terminal hydroxyl polysiloxane and 1,4-butanediol, add it to the reactor, heat it to 75°C, wait for the reaction system to cool to room temperature after the reaction is completed, add ethanol to the reaction solution, heat the reactor to 110-120°C, and distill under reduced pressure until no liquid is recovered to obtain a modified polyurethane precursor;

[0071] Weigh: 80g of modified polyurethane precursor, 20g of KH-550 and 1.5L of toluene, place them in a reactor, heat to 90°C, and keep warm for 2h. After the reaction is completed, add ethanol to the reaction liquid, heat the reaction to 100°C, and distill under reduced pressure until no liquid is extracted to obtain modified polyurethane.

[0072] S2. Preparation of modified flame retardant

[0073] Weigh 100 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 400 mL of ethanol, mix them evenly to obtain a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution, and set aside.

[0074] Weigh: 50 g of p-methylphenylethylamine, 40 g of 2-phenylpropanal, and 1 L of ethanol into a reaction kettle, heat to 80°C, and stir for 4 h. After the reaction is complete, filter and wash the filter cake twice with ethanol, transfer to a drying oven at 50°C, and dry to constant weight to obtain Intermediate I;

[0075] Weigh: 100 g of intermediate I, 1 L of ethanol, and 100 mL of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution into a reactor, heat to 80°C, and keep warm for 8 hours. After the reaction is completed, cool the temperature to room temperature, filter, wash the filter cake twice with ethanol, transfer to a drying oven at 50°C, and dry to constant weight to obtain intermediate II;

[0076] Weigh: 120 g of intermediate II, 20 g of 3-isocyanatepropyltriethoxysilane, 15 g of triethylamine and 2 L of toluene, place them in a reactor, heat to 100°C, and keep warm for 4 hours. After the reaction is completed, add ethanol to the reaction liquid, heat to 100°C, and distill under reduced pressure until no liquid is extracted to obtain a modified flame retardant.

[0077] S3. Preparation of modified sepiolite

[0078] 30 mm, 40 mm and 50 mm ceramic balls are mixed uniformly in a mass ratio of 1:1:1 to obtain a ceramic ball mixture;

[0079] Weigh: 100 g of sepiolite and 1 L of 0.5 mol / mL dilute nitric acid, place them in a reactor, heat to 20°C, keep stirring for 12 hours, filter, wash and dry, add the dried solid and ceramic ball mixture into the ball mill of a planetary ball mill, and ball mill for 30 minutes to obtain modified sepiolite.

[0080] S4. Prepare cables

[0081] Copper-tin alloy wires are twisted together to form a conductor to obtain a core 1. After being placed in parallel, styrene-butadiene rubber is extruded around the core 1 to form an insulating rubber layer 2. Polyester tape is then wrapped around the cores 1 to form a wrapping layer 3.

[0082] Mix barium stearate, antioxidant MBI and carbon black in a weight ratio of 1:1:2 to obtain an auxiliary additive for later use;

[0083] Weigh 20-30 parts of modified polyurethane, 5-10 parts of modified flame retardant, 15-20 parts of modified sepiolite and 2-4 parts of auxiliary additives by weight, add them into a twin-screw extruder, and melt-extrude them on the outside of the wrapping layer 3 to obtain a high-temperature resistant and torsion-resistant cable.

[0084] Example 2

[0085] A high-temperature resistant and twist-resistant cable according to this embodiment includes the following steps:

[0086] S1. Preparation of modified polyurethane

[0087] Weigh: 70 g of octamethylcyclotetrasiloxane, 30 mL of 13 wt% sodium hydroxide solution, and 700 mL of toluene, place them in a reactor protected by a nitrogen atmosphere, heat to 90 ° C, and keep the temperature for 2 hours. After the reaction is completed, wait for the reaction system to cool to room temperature, add ethyl acetate and pure water to the reaction solution, wash twice, and transfer the organic phase to a rotary evaporator at a temperature of 45 ° C and rotate until no liquid is recovered to obtain terminal hydroxyl polysiloxane;

[0088] Weigh: 70 g of terminal hydroxyl polysiloxane, 50 g of 1,4-butanediol, 10 g of dibutyltin dilaurate, and 1.1 L of toluene, place them in a reactor protected by a nitrogen atmosphere and stir, weigh diphenylmethane diisocyanate at twice the molar amount of the hydroxyl group in the terminal hydroxyl polysiloxane and 1,4-butanediol, add it to the reactor, heat it to 80°C, wait for the reaction system to cool to room temperature after the reaction is completed, add ethanol to the reaction solution, heat the reactor to 110-120°C, and distill under reduced pressure until no liquid is produced to obtain a modified polyurethane precursor;

[0089] Weigh: 110 g of modified polyurethane precursor, 25 g of KH-550 and 1.7 L of toluene, place them in a reactor, heat to 100 ° C, and keep warm for 2 hours. After the reaction is completed, ethanol is added to the reaction liquid, the reaction temperature is raised to 105 ° C, and vacuum distillation is carried out until no liquid is extracted to obtain modified polyurethane.

[0090] S2. Preparation of modified flame retardant

[0091] Weigh: 110 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 450 mL of ethanol, mix evenly to obtain a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution, set aside;

[0092] Weigh 60 g of p-methylphenylethylamine, 50 g of 2-phenylpropanal, and 1.2 L of ethanol into a reaction kettle, heat to 85°C, and stir for 6 h. After the reaction is complete, filter and wash the filter cake twice with ethanol, transfer to a drying oven at 55°C, and dry to constant weight to obtain Intermediate I.

[0093] Weigh: 110 g of intermediate I, 1.1 L of ethanol and 120 mL of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution into a reactor, heat to 85, and keep warm for 10 hours. After the reaction is completed, cool to room temperature, filter, wash the filter cake twice with ethanol, transfer to a drying oven at 55°C, and dry to constant weight to obtain intermediate II;

[0094] Weigh: 135 g of intermediate II, 25 g of 3-isocyanatepropyltriethoxysilane, 17 g of triethylamine and 2.2 L of toluene, place them in a reactor, heat to 110°C, and keep warm for 5 hours. After the reaction is completed, add ethanol to the reaction liquid, heat to 110°C, and distill under reduced pressure until no liquid is extracted to obtain a modified flame retardant.

[0095] S3. Preparation of modified sepiolite

[0096] 30 mm, 40 mm and 50 mm ceramic balls are mixed uniformly in a mass ratio of 1:1:1 to obtain a ceramic ball mixture;

[0097] Weigh: 150 g of sepiolite and 1.2 L of 1.5 mol / mL dilute nitric acid, place them in a reactor, heat to 25°C, keep stirring for 14 hours, filter, wash and dry, add the dried solid and ceramic ball mixture into the ball mill of a planetary ball mill, and ball mill for 40 minutes to obtain modified sepiolite.

[0098] S4. Prepare cables

[0099] Copper-tin alloy wires are twisted together to form a conductor to obtain a core 1. After being placed in parallel, styrene-butadiene rubber is extruded around the core 1 to form an insulating rubber layer 2. Polyester tape is then wrapped around the cores 1 to form a wrapping layer 3.

[0100] Mix barium stearate, antioxidant MBI and carbon black in a weight ratio of 1:1:2 to obtain an auxiliary additive for later use;

[0101] Weigh 26 parts of modified polyurethane, 7 parts of modified flame retardant, 17 parts of modified sepiolite and 3 parts of auxiliary additives by weight, add them into a twin-screw extruder, melt-extrude them on the outside of the wrapping layer 3, and obtain a high-temperature resistant and torsion-resistant cable.

[0102] Example 3

[0103] A high-temperature resistant and twist-resistant cable according to this embodiment includes the following steps:

[0104] S1. Preparation of modified polyurethane

[0105] Weigh: 100 g of octamethylcyclotetrasiloxane, 40 mL of 15 wt% sodium hydroxide solution, and 900 mL of toluene are placed in a reactor protected by a nitrogen atmosphere, heated to 105°C, and kept warm for 2 hours. After the reaction is completed, the reaction system is cooled to room temperature, ethyl acetate and pure water are added to the reaction solution, and washed twice. The organic phase is transferred to a rotary evaporator at a temperature of 50°C and rotated until no liquid is recovered to obtain a hydroxy-terminated polysiloxane;

[0106] Weigh: 100 g of terminal hydroxyl polysiloxane, 60 g of 1,4-butanediol, 15 g of dibutyltin dilaurate, and 1.2 L of toluene, place them in a reactor protected by a nitrogen atmosphere and stir, weigh diphenylmethane diisocyanate at twice the molar amount of the hydroxyl group in the terminal hydroxyl polysiloxane and 1,4-butanediol, add it to the reactor, heat it to 85°C, wait for the reaction system to cool to room temperature after the reaction is completed, add ethanol to the reaction solution, heat the reactor to 110-120°C, and distill under reduced pressure until no liquid is extracted to obtain a modified polyurethane precursor;

[0107] Weigh: 130g of modified polyurethane precursor, 30g of KH-550 and 2L of toluol, place them in a reactor, heat to 110°C, and keep warm for 2h. After the reaction is completed, add ethanol to the reaction liquid, heat the reaction to 110°C, and distill under reduced pressure until no liquid is extracted to obtain modified polyurethane.

[0108] S2. Preparation of modified flame retardant

[0109] Weigh: 120 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 500 mL of ethanol, mix them evenly to obtain a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution, and set aside;

[0110] Weigh 70 g of p-methylphenylethylamine, 60 g of 2-phenylpropanal, and 1.5 L of ethanol into a reaction kettle, heat to 90°C, and stir for 6 h. After the reaction is complete, filter and wash the filter cake twice with ethanol, transfer to a drying oven at 60°C, and dry to constant weight to obtain Intermediate I.

[0111] Weigh: 120 g of intermediate I, 1.2 L of ethanol, and 150 mL of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution into a reactor, heat to 90°C, and keep warm for 10 hours. After the reaction is completed, cool to room temperature, filter, wash the filter cake twice with ethanol, transfer to a drying oven at 60°C, and dry to constant weight to obtain intermediate II;

[0112] Weigh: 150 g of intermediate II, 30 g of 3-isocyanatepropyltriethoxysilane, 20 g of triethylamine and 2.5 mL of toluene, place them in a reactor, heat to 120°C, and keep warm for 6 hours. After the reaction is completed, add ethanol to the reaction liquid, heat to 120°C, and distill under reduced pressure until no liquid is extracted to obtain a modified flame retardant.

[0113] S3. Preparation of modified sepiolite

[0114] 30 mm, 40 mm and 50 mm ceramic balls are mixed uniformly in a mass ratio of 1:1:1 to obtain a ceramic ball mixture;

[0115] Weigh: 200 g of sepiolite and 1.5 L of 1.5 mol / mL dilute nitric acid are placed in a reactor, heated to 30°C, stirred at this temperature for 16 hours, filtered, washed and dried, and the dried solid and ceramic ball mixture is added to the ball mill of a planetary ball mill. After ball milling for 40 minutes, the modified sepiolite is obtained.

[0116] S4. Prepare cables

[0117] Copper-tin alloy wires are twisted together to form a conductor to obtain a core 1. After being placed in parallel, styrene-butadiene rubber is extruded around the core 1 to form an insulating rubber layer 2. Polyester tape is then wrapped around the cores 1 to form a wrapping layer 3.

[0118] Mix barium stearate, antioxidant MBI and carbon black in a weight ratio of 1:1:2 to obtain an auxiliary additive for later use;

[0119] Weigh 30 parts of modified polyurethane, 10 parts of modified flame retardant, 20 parts of modified sepiolite and 4 parts of auxiliary additives by weight, add them into a twin-screw extruder, melt-extrude them on the outside of the wrapping layer 3, and obtain a high-temperature resistant and torsion-resistant cable.

[0120] Comparative Example 1

[0121] The difference between this comparative example and Example 3 is that the step of preparing modified polyurethane in step S1 is eliminated, and an equal amount of modified polyurethane precursor is used to replace modified polyurethane in the process of preparing the cable sheath layer.

[0122] Comparative Example 2

[0123] The difference between this comparative example and Example 3 is that the step of preparing the modified flame retardant in step S2 is eliminated, and an equal amount of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is used to replace the modified flame retardant in the process of preparing the cable sheath layer.

[0124] Comparative Example 3

[0125] The difference between this comparative example and Example 3 is that the acidification treatment of sepiolite in step S3 is omitted, and an equal amount of sepiolite is used to replace the modified sepiolite during the preparation of the cable sheath layer.

[0126] Performance testing:

[0127] The tensile strength, elongation at break, heat aging resistance, and flame retardancy of the cable samples prepared in Examples 1-3 and Comparative Examples 1-3 were tested with reference to Standard XF 306.1-2007 "Classification and requirements for flame retardant and fire resistant cables with plastic insulation Part 1: Flame retardant cables".

[0128] According to the standard GB / T 33606-2017 "Twisting-resistant flexible cable for wind power generation with rated voltage of 6 kV (Um=7.2 kV) to 35 kV (Um=40.5 kV)", the cable samples prepared in Examples 1-3 and Comparative Examples 1-3 were tested for their torsion resistance after 1000 torsion test cycles at room temperature;

[0129] With reference to the standard GB / T 17651.2-2021 "Determination of smoke density of electric cables or optical cables burning under specific conditions Part 2: Test procedures and requirements", the cable samples prepared in Examples 1-3 and Comparative Examples 1-3 were tested for smoke transmittance after burning for 20 minutes. The specific data are shown in Table 1.

[0130] Table 1-Performance test data of the sample

[0131]

[0132] Data Analysis:

[0133] Analysis of the data in Table 1 above shows that the high-temperature resistant and torsion-resistant cable prepared by the present invention has a tensile strength of 18.2 MPa and an elongation at break of 219.4% before heat aging; a tensile strength of 17.1 MPa and an elongation at break of 205.2% after heat aging; a smoke transmittance of 32.0%; and a flame retardant grade of IA. After 1000 torsion test cycles, the cable sample has no cracks and no torsion.

[0134] By comparing the data of Comparative Example 1 and Example 3, it can be seen that the tensile strength, elongation at break and flame retardancy of the cable before and after thermal aging are significantly reduced, and after 1000 cycles of the torsion test, cracks and twisting occur in the cable sample, indicating that a modified polyurethane precursor with a siloxy bond and a phenyl group is prepared by polymerization of hydroxy-terminated polysiloxane, 1,4-butanediol and diphenylmethane diisocyanate, and further cross-linked with a silane coupling agent to prepare a modified polyurethane, which can improve the mechanical strength, high temperature resistance and torsion resistance of the cable;

[0135] By comparing the data of Comparative Example 2 and Example 3, it can be seen that the tensile strength, elongation at break, smoke resistance and flame retardant properties of the cable before and after thermal aging are significantly reduced, indicating that the modified flame retardant contains a large amount of phosphorus and oxygen elements. These elements can release phosphoric acid or phosphorus oxides under high temperature or fire conditions. Phosphorus atoms inhibit the generation of combustible gases through catalytic reactions and delay the occurrence of thermal decomposition reactions. Phosphates can reduce the temperature of the fire source through endothermic reactions and prevent further combustion of the material. Due to the unique effect of phosphorus, the protective sheath of the cable can form a hard carbonized layer when exposed to high temperatures, further isolating oxygen, reducing the continuous effect of flames on the material, and reducing the generation of toxic gases.

[0136] Through the data analysis and comparison of comparative example 3 and embodiment 3, it can be seen that the tensile strength, elongation at break, smoke resistance and flame retardant performance of the cable before and after thermal aging are significantly reduced, and after 1000 cycles of the torsion test, cracks and twisting occur in the cable sample, indicating that the structure of sepiolite itself contains silicon-oxygen tetrahedrons and is rich in natural fibrous minerals such as Mg and Si non-halogen flame retardant elements. It has low thermal conductivity and high temperature resistance and can form a protective carbonized layer when a fire occurs. This carbonized layer can effectively isolate oxygen, delay the spread of flames, and improve the high temperature resistance and flame retardant properties of the cable. After being treated with dilute nitric acid, the surface of the sepiolite is Impurities on the surface are removed, the original pores are expanded, a more developed multi-level pore structure is formed, the specific surface area is increased, more silicone hydroxyl groups are introduced, and the active sites are increased. Sepiolite is a low-density mineral. Adding it to the cable sheath can reduce the total weight of the sheath layer and reduce the concentration of internal stress during cable application, thereby improving the cable's anti-twisting performance. After ball milling, the particle size of the modified sepiolite is uniform, which improves its dispersibility in modified polyurethane, modified flame retardant and auxiliary additives. The silicone hydroxyl groups on its surface react with the silicon-oxygen bonds in the modified polyurethane and modified flame retardant to form chemical crosslinks through condensation reactions, further improving the mechanical properties of the cable.

[0137] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high temperature resistant and twist resistant cable, characterized in that: It comprises a plurality of wire cores (1), a wrapping layer (3) and a sheath layer (4) arranged in sequence from the inside out; The wire core (1) comprises a conductor consisting of a plurality of mutually twisted metal alloy wires and an insulating rubber layer (2) covering the outside of the conductor; The wrapping layer (3) is obtained by wrapping the wrapping tape around the outside of the plurality of wire cores (1); The sheath layer (4) comprises the following components in parts by weight: 20-30 parts of modified polyurethane, 5-10 parts of modified flame retardant, 15-20 parts of modified sepiolite and 2-4 parts of auxiliary additives; The modified polyurethane is obtained by the following preparation method: A1. Place octamethylcyclotetrasiloxane, sodium hydroxide solution and toluene in a reactor protected by nitrogen atmosphere, heat to 85-105° C., keep warm for 1-2 hours, and post-treat to obtain hydroxyl-terminated polysiloxane; A2. Place hydroxy-terminated polysiloxane, 1,4-butanediol, dibutyltin dilaurate, toluene, and diphenylmethane diisocyanate in a reactor protected by a nitrogen atmosphere, heat to 75-85° C., and perform post-treatment to obtain a modified polyurethane precursor; A3. Place the modified polyurethane precursor, KH-550 and toluene in a reactor, heat to 90-110° C., keep the temperature for 1-2 hours, and perform post-treatment to obtain the modified polyurethane; The preparation method of the modified flame retardant comprises the following steps: B1. Place p-methylphenylethylamine, 2-phenylpropanal and ethanol in a reaction kettle, heat to 80-90°C, stir for 4-6 hours, and post-treat to obtain intermediate I; B2. Place intermediate I, ethanol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution in a reaction kettle, heat to 80-90°C, keep warm for 8-10 hours, and post-treat to obtain intermediate II; B3. Place intermediate II, 3-isocyanatepropyltriethoxysilane, triethylamine and toluene in a reaction kettle, heat to 100-120°C, keep warm for 4-6 hours, and post-treat to obtain a modified flame retardant; The preparation method of the modified sepiolite comprises the following steps: placing sepiolite and dilute nitric acid in a reaction kettle, heating to 20-30° C., stirring at the temperature for 12-16 hours, filtering, washing, drying, and ball milling to obtain the modified sepiolite.

2. A high temperature resistant and twist resistant cable according to claim 1, characterized in that: The metal alloy wire is a copper-tin alloy wire, the insulating rubber layer is one or more of styrene-butadiene rubber, ethylene-propylene rubber, and chloroprene rubber, and the wrapping tape is one or more of polyester tape and aluminum metal tape; in step A1, the concentration of the sodium hydroxide solution is 10-15wt%, and the amount ratio of the octamethylcyclotetrasiloxane, sodium hydroxide solution, and toluene is 5-10g:2-4mL:60-90mL; in step A2, the molar amount of the diphenylmethane diisocyanate is twice the molar amount of the hydroxyl group in the terminal hydroxyl polysiloxane and 1,4-butanediol, and the amount ratio of the terminal hydroxyl polysiloxane, 1,4-butanediol, dibutyltin dilaurate, and toluene is 5-10g:4-6g:0.1-1.5g:100-120mL; in step A3, the amount ratio of the modified polyurethane precursor, KH-550, and toluene is 8-13g:2-3g:150-200mL.

3. The high temperature resistant and twist resistant cable according to claim 1, characterized in that: The preparation method of the sheath layer (4) is as follows: adding modified polyurethane, modified flame retardant, modified sepiolite and auxiliary additives into a twin-screw extruder, and melt-extruding them on the outside of the wrapping layer (3), thereby forming the sheath layer (4) on the outside of the wrapping layer (3).

4. A high temperature resistant and twist resistant cable according to claim 3, characterized in that: The auxiliary additives are composed of a lubricant, an antioxidant, and a filler in a weight ratio of 1:1:

2. The lubricant is one or more of barium stearate and silicone oil. The antioxidant is one or more of antioxidant 6PPD, antioxidant MB, and antioxidant MBI. The filler is one or more of carbon black, montmorillonite, and calcium carbonate.

5. The high temperature resistant and twist resistant cable according to claim 1, characterized in that: In step B1, the amount ratio of p-methylphenylethylamine, 2-phenylpropanal and ethanol is 5-7g:4-6g:100-150mL; in step B2, the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution is composed of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and ethanol in a ratio of 10-12g:40-50mL, and the amount ratio of intermediate I, ethanol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide solution is 10-12g:100-120mL:10-15mL; in step B3, the amount ratio of intermediate II, 3-isocyanatopropyltriethoxysilane, triethylamine and toluene is 12-15g:2-3g:1.5-2g:200-250mL.

6. The high temperature resistant and twist resistant cable according to claim 1, characterized in that: The concentration of the dilute nitric acid is 0.5-1.5 mol / mL, and the usage ratio of the sepiolite to the dilute nitric acid is 10-20 g:100-150 mL.

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