High-performance anti-interference fireproof cable and preparation method thereof

Abstract

The application discloses a kind of high-performance anti-interference fireproof cable, from inside to outside include successively: conductor core layer, shielding layer, mica tape winding fireproof layer and outer sheath layer;The conductor core layer is symmetrical star type stranding of multiple tinned copper wire, gap filling boron-containing zinc glass rope;The shielding layer is surface composite polyaniline / carbon black coating aluminum-magnesium alloy wire woven net;The outer sheath layer contains 65~70 parts of resin matrix component, which is copolymerized from phosphorus heteroheptacyclophane-triazine-silane-based diene A section monomer and benzoxazole-thiophene-pyrazole-based diene B section monomer.The high-performance anti-interference fireproof cable provided by the application, its preparation method includes shielding layer forming, flame-retardant mica tape preparation, outer sheath layer resin matrix and outer sheath material preparation process, then through cable assembly operation, mechanical properties, shielding effectiveness, fire safety breakthrough is realized, can satisfy the demand of high-end equipment field to cable in high shielding, high flame-retardant, high flexibility.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a high-performance anti-interference fireproof cable and its preparation method. Background Technology

[0002] With the rapid development of construction, rail transportation, and new energy power generation, the number of electrical equipment and communication systems continues to rise, leading to increasingly stringent requirements for cable safety and signal transmission stability. High-performance, anti-interference, and fire-resistant cables have become crucial components. However, traditional cables have many drawbacks. First, many traditional cables have poor flame-retardant properties, making them highly flammable and releasing large amounts of toxic fumes during a fire. This not only accelerates the spread of fire, posing a serious threat to human life, but also causes significant environmental damage. Second, cables are often subject to external electromagnetic interference when transmitting signals, resulting in a significant reduction in signal transmission quality and affecting the normal operation of equipment. Third, cables directly exposed to humid or salt spray environments are prone to galvanic corrosion; after 1000 hours of salt spray exposure, the volume resistivity increases by more than 30%, and the shielding performance drops sharply.

[0003] Therefore, existing technologies cannot simultaneously solve the problem of synergistic effects of anti-interference, flame retardancy, and weather resistance; there is an urgent need to develop new processes and materials to prepare high-performance anti-interference fireproof cables. Summary of the Invention

[0004] The purpose of this invention is to provide a high-performance anti-interference fireproof cable and its preparation method.

[0005] To solve the above-mentioned technical problems, the present invention provides a high-performance anti-interference fireproof cable, comprising, from the inside out:

[0006] Conductor core layer: symmetrical star-shaped stranded structure of multi-strand tin-plated copper wire, with a stranding pitch of 8-12 times the conductor diameter; gaps are filled with zinc borate-containing fiberglass rope;

[0007] Shielding layer: Aluminum-magnesium alloy wire woven mesh covering the core layer, with a weaving density of ≥90%; surface is coated with polyaniline / carbon black.

[0008] Fireproof layer: A mica tape covering the shielding layer is wrapped around the surface and coated with a flame-retardant adhesive; the flame-retardant adhesive contains nano-sheet aluminum hydroxide, polyphosphate melamine salt and organosilicon resin;

[0009] Outer sheath layer: by weight, it contains 65-70 parts of resin matrix component; the resin matrix is ​​copolymerized from monomers of segment A and segment B;

[0010] Segment A is a phosphaphenanthrene-triazine silyl diene monomer with a structure as shown in Formula I:

[0011] (I); among which, ;

[0012] Segment B is a benzoxazole-thiophene-pyrazolyl diene monomer with a structure as shown in Formula II:

[0013] (II); among which,

[0014] , One of Y1, Y2, Y3, and Y4 is connected to M through an oxygen atom, while the rest are H atoms.

[0015] Furthermore, the outer sheath layer, by weight, further includes:

[0016] 22-30 parts of functional filler, including: 7-10 parts of fly ash and 15-20 parts of magnesium hydroxide;

[0017] Additives, 4.5-5 parts, including: 0.3-0.5 parts α-tocopherol, 0.5-0.8 parts phosphite antioxidant, 1.8-2.1 parts silicone lubricant, 0.3-0.5 parts zinc stearate, 0.1-0.3 parts hydrotalcite, 1.0-1.2 parts vulcanizing agent and 0.5-0.6 parts accelerator;

[0018] The fly ash has a 45μm sieve residue of ≤10wt%, and the D50 particle size of magnesium hydroxide is 5~10μm; the vulcanizing agent is dicumyl peroxide, and the accelerator is triallyl isocyanurate.

[0019] Furthermore, the zinc borate loading in the conductor core layer is 8-10 wt%.

[0020] The shielding layer has a polyaniline / carbon black composite coating with a thickness of 0.2~0.4mm, which is formed by in-situ polymerization and spin coating processes.

[0021] The flame-retardant adhesive of the fireproof layer has a solid content of 40-50%, and its solids, by mass, include: 100 parts of organosilicon resin, 45-50 parts of nano-sheet aluminum hydroxide, and 5-8 parts of polyphosphate melamine salt; the organosilicon resin is methylphenyl silicone resin, and the specific surface area of ​​the nano-sheet aluminum hydroxide is ≥20m². 2 / g, the nitrogen content of polyphosphate melamine salt is ≥38wt%, and the phosphorus content is ≥14wt%.

[0022] Furthermore, the A-segment monomer is synthesized via the following pathway:

[0023] Under a sulfuric acid (S1) and nitrogen (N2) atmosphere, 2-vinyl-4,6-diamino-1,3,5-triazine and DOPO were reacted at a molar ratio of 1:0.99-1.05 with an acid catalyst and a phase transfer catalyst at 100-115°C for 5-8 h to obtain intermediate A1. The acid catalyst was trifluoromethanesulfonic acid, and the phase transfer catalyst was tetrabutylammonium bromide, with amounts of 0.8-1.5 wt% and 0.1-0.2 wt% of the total mass of the reactants, respectively.

[0024] Under an S2-N2 atmosphere, an A1 intermediate with a molar ratio of 1:2.05-2.20 and a terminal alkenyl hydroxysilane derivative are nucleophilically substituted at 80-95°C for 3-5 hours under the catalysis of potassium hydroxide and a crown ether to obtain the A-segment monomer; the amount of potassium hydroxide used is 1.0-1.2 times the molar amount of the A1 intermediate, and the crown ether is 18-crown-6 with a molar ratio of 0.05-0.10:1 to the A1 intermediate;

[0025] The terminal alkenyl hydroxysilane derivative is selected from 1-hydroxyallyltrimethylsilane (95061-68-0), 2-hydroxy-3-[3-(trimethoxysilyl)propoxy]propyl methacrylate (59214-63-0) or allyloxy-tert-butyl-dimethylsilane (105875-75-0).

[0026] Furthermore, the B-segment monomer is synthesized via the following pathway:

[0027] 1) Under N2 atmosphere, 1,3-benzoxazole-y-ol and vinyl-1H-pyrazole in a molar ratio of 1:0.99~1.03 were reacted in a halosol in a halogenated solvent at room temperature for 45~50 h via an oxidative coupling system to obtain intermediate B1, where y=4,5,6,7;

[0028] The oxidative coupling system comprises 2,2,6,6-tetramethylpiperidine oxide and (diacetoxyiodine)benzene, in amounts of 1.0 to 1.2 times and 1.8 to 2.2 times the molar amount of benzoxazole-γ-ol, respectively.

[0029] 2) Under N2 atmosphere, intermediate B1 and dibromothiophene derivative react at a molar ratio of 1.95~2.05 with K2CO3 catalysis at 70~85℃ for 4~6h to obtain monomer B; the amount of potassium carbonate used is 2.0~2.5 times the molar amount of intermediate B1.

[0030] The dibromothiophene derivative is selected from 2,5-dibromo-3,4-vinyldioxythiophene or 2,5-dibromothiophene[3,2-b]thiophene.

[0031] On the other hand, the present invention provides a method for preparing the above-mentioned cable, comprising the following steps:

[0032] (1) Shielding layer forming: After in-situ polymerization of polyaniline, aluminum-magnesium alloy mesh is spin-coated with carbon black slurry and cured;

[0033] (2) Preparation of flame-retardant mica tape: Prepare a silicone resin flame-retardant adhesive containing nano-sheet aluminum hydroxide and polyphosphate melamine salt; then coat it onto the mica tape substrate and dry it;

[0034] (3) Synthesis of resin matrix: In the presence of an inert atmosphere and a catalyst system, the monomer of section A undergoes a first polymerization reaction at a first temperature; the temperature is increased to a second temperature at a rate of 1~2℃ / min, and the monomer of section B is added to carry out a second polymerization reaction; after the reaction is completed, it is terminated by an ice-water bath to obtain the resin matrix melt;

[0035] (4) Preparation of outer sheath material:

[0036] ① Mixing: In the twin-screw extruder, add 70~80wt% of the resin matrix from step (3), α-tocopherol and phosphite antioxidants to the main feed port, and add pretreated magnesium hydroxide and fly ash after melting; add the remaining resin matrix and other additives except for the vulcanization accelerator to the side feed port;

[0037] ②Extrusion: The twin screw speed is 250~300rpm, the temperature gradient is 140~170℃, and the extrusion granulation is carried out at 150~170℃ to obtain masterbatch;

[0038] ③ Mixing: The masterbatch and vulcanization accelerator are sheared, mixed, and vulcanized to obtain the outer sheath material;

[0039] (5) Cable assembly: The conductor core layer is sequentially covered with the shielding layer of step (1), the flame-retardant mica tape of step (2), and the outer sheath material of step (4); after step vulcanization, gradient cooling, and annealing, it is wound into a coil.

[0040] Further, in step (1): the in-situ polymerization conditions of polyaniline are: 10wt% aniline hydrochloride aqueous solution impregnates aluminum-magnesium alloy mesh, adsorbs at 25℃ for 30min; then ammonium persulfate with the same molar amount as aniline is added dropwise, and polymerization is carried out for 2h; the spin coating speed is 3000±1000rpm, and the curing parameters are: curing at 80℃ for 10~20min.

[0041] The in-situ polymerized polyaniline layer exhibits extremely strong adhesion to the metal substrate, forming a continuously conductive network with robust adhesion. Subsequent spin-coated carbon black particles fill this gap, creating a stable and synergistic conductive architecture with extremely low and stable resistance. Polyaniline possesses electromagnetic wave absorption properties, while the carbon black / metal mesh tends to reflect. This dual shielding mechanism of "absorption layer + reflection layer" achieves wider-band and more efficient electromagnetic interference shielding.

[0042] Furthermore, in step (3): the feeding rate of the monomer in segment A is 0.5~0.7 mL / min, the time of the first polymerization reaction is 2~3 h, and the first temperature is 58~65℃; to ensure that the chain in segment A grows sufficiently to form a sufficiently long rigid block segment;

[0043] The feeding rate of the B-segment monomer is 0.7~0.9 mL / min, the second polymerization reaction time is 3.5~4.5 h, and the second temperature is 68~75 °C. This allows for complete incorporation of the B-segment monomer, enhancing chain fluidity and forming a good AB block copolymer structure, reducing unreacted monomers.

[0044] The catalyst system includes an initiator, a copper salt catalyst, and a ligand, with a molar ratio of (0.7~1.0):(1.5~2.5):1. The initiator is ethyl 2-bromoisoethylbutyrate, the copper salt catalyst is cuprous bromide, and the ligand is N,N,N',N'',N''-pentamethyldivinyltriamine.

[0045] Further, in step (4): the temperature gradient of the twin-screw extruder is as follows: 140℃ for the feeding section, 150~160℃ for the melting section, 170~180℃ for the mixing section, and 160~165℃ for the extrusion section; the feeding temperature of the side feed port is ≤100℃ and the rotation speed is ≤280rpm; the vulcanization operation is carried out in a continuous vulcanization pipeline at a temperature of 160~170℃, a pressure of 12~15MPa, a vulcanization time of 10~15min, and a cooling rate of 5~8℃ / min.

[0046] Further, in step (5): the gradient vulcanization operation is as follows: after the cable is wrapped, it is sent into a continuous vulcanization pipeline and nitrogen gas is introduced for protection. First, it is vulcanized at 140~150℃ and 12~15MPa for 5 minutes, and then the temperature is raised to 160~170℃ and 15~20MPa for 8 minutes.

[0047] The gradient cooling operation is as follows: after vulcanization, the cable is sequentially treated with an 80°C hot water bath for 5 minutes, a 50°C warm water bath for 5 minutes, and finally water-cooled at 25°C for 10 minutes, with a cooling rate of 5~8°C / min.

[0048] The annealing process involves placing the cooled cable in an oven at 70-80°C for 2-4 hours and then allowing it to cool naturally to room temperature.

[0049] Beneficial effects:

[0050] The cable of this invention achieves breakthroughs in mechanical properties, shielding effectiveness, and fire safety:

[0051] Balance between high tensile strength and toughness: Benzooxazole, thiophene, and phosphaphenanthrene groups provide rigid support, while silane groups provide flexible connections, enabling the outer sheath to simultaneously possess high tensile strength (≥30MPa) and excellent elongation at break (≥300%).

[0052] Dual shielding mechanism: The internal aluminum-magnesium alloy braided mesh provides physical shielding, the surface polyaniline / carbon black coating provides absorption shielding, and the thiophene / benzoxazole conjugated structure of the B-segment monomer in the sheath layer forms a molecular-level electromagnetic reflection network. The three work together to achieve a high shielding efficiency of over 75 dB, effectively suppressing high-frequency electromagnetic interference.

[0053] Synergistic flame retardancy between gas phase and condensed phase: The phosphorus-phenanthrene groups of the A-segment monomer release phosphorus free radicals during combustion, capturing free radicals in the gas phase combustion chain reaction; simultaneously, triazine and pyrazole groups synergistically retard the flame. In the fireproof layer, nano-sheet aluminum hydroxide decomposes endothermally and releases water vapor, while polyphosphate melamine salt promotes char formation; the magnesium hydroxide filler in the sheath decomposes endothermally, collectively achieving excellent flame retardancy with a limiting oxygen index (LOI) ≥36%, achieving UL94 V-0 certification. Furthermore, the zinc borate / fiberglass rope filling layer and halogen-free formulation effectively suppress the release of smoke and toxic gases during combustion.

[0054] Process integration and low-temperature and low-pressure processability: The melt index of the copolymer resin matrix is ​​optimized to ≤18g / 10min, which has good processability, low energy consumption and avoids high-temperature degradation; the vulcanization molding has high production efficiency and good product consistency. Attached Figure Description

[0055] Figure 1 The 1H NMR spectrum of monomer 1 obtained from the synthesis of segment A in Preparation Example 1.

[0056] Figure 2 The 1H NMR spectrum of monomer 2 in segment A obtained from preparation example 2.

[0057] Figure 3 The 1H NMR spectrum of monomer 1 obtained from the synthesis of segment B in Preparation Example 3.

[0058] Figure 4 The 1H NMR spectrum of monomer 2 obtained from the synthesis of segment B in Preparation Example 4.

[0059] Figure 5 The complete preparation route of the high-performance anti-interference fireproof cable in Example 1. Detailed Implementation

[0060] To more fully demonstrate the practical applications and technical advantages of the present invention, the following detailed description is provided through multiple embodiments and comparative examples. Those skilled in the art should understand that these embodiments are merely examples and do not constitute a limitation on the scope of protection of the present invention.

[0061] Unless otherwise specified, the experimental methods used in the specific implementation methods are all conventional methods; the materials and reagents used are all commercially available unless otherwise specified.

[0062] The properties and sources of some raw materials used in the examples and comparative examples are as follows:

[0063] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), CAS No.: 35948-25-5, purity 99%.

[0064] Benzooxazol-5-ol, CAS No.: 180716-28-3, purity 97%.

[0065] 5-Bromo-2-(3,4-vinyldioxythiophene)formaldehyde, CAS: 852054-42-3, purity 98%.

[0066] 2-Vinyl-4,6-diamino-1,3,5-triazine, CAS No.: 3194-70-5, purity 95%;

[0067] 3-Vinyl-1H-pyrazole, CAS No.: 56342-52-0, purity 97%.

[0068] 1-Allyloxy-tert-butyl-dimethylsilane, CAS No.: 105875-75-0, purity 98%.

[0069] 2-Hydroxy-3-[3-(trimethoxysilyl)propoxy]propyl methacrylate, CAS No.: 59214-63-0.

[0070] 2,2,6,6-Tetramethylpiperidine oxide (TEMPO), CAS No.: 2564-83-2, purity 99.6%.

[0071] (Diacetoxyiodine)benzene (DIB), CAS No.: 3240-34-4, purity 98%.

[0072] 2,6-Di-tert-butyl-p-cresol (BHT), CAS No.: 128-37-0, chemically pure.

[0073] Ethyl 2-bromoisobutyrate (EBiB), CAS: 600-00-0, purity 98%.

[0074] DL-α-Tocopherol, CAS: 10191-41-0, purity >96.0%, CB index 62.

[0075] 2,5-Dibromothiopheno[3,2-b]thiophene, CAS No.: 25121-87-3, purity 97%.

[0076] CuBr, CAS No.: 7787-70-4, purity 99.99%.

[0077] Pentamethyldiethylenetriamine (PMDETA), CAS: 3030-47-5, purity 98%.

[0078] Dicumyl peroxide (DCP), 99% purity.

[0079] Triallyl isocyanurate (TAIC) content > 99%.

[0080] Rubber carbon black N330, conforming to standard GB3778-2011, Shandong Kasong.

[0081] Aluminum-magnesium wire woven mesh, Dongguan Changsheng Electric Technology Co., Ltd.

[0082] XS-ZB-2335 zinc borate is a white powder with ZnO content of 37wt%, B2O3 content of 45wt%, moisture content ≤0.5wt%, weight loss on ignition of 13.5~15.5wt%, electrical conductivity ≤2000us / cm, 1% decomposition temperature of 300℃ (N2), and average particle size D50=5μm. It is produced by Zhejiang Xusen Flame Retardant Co., Ltd.

[0083] Melamine pyrophosphate (MPP), phosphorus content >14wt%, nitrogen content >38wt%, Shandong Shian Chemical Co., Ltd.

[0084] ZM-QXG-F3 type magnesium hydroxide, particle size D50 = 5μm, specific surface area = 12m² 2 / g, Mg(OH)2 content ≥99wt% (dry basis), loss on ignition ≤30wt%, Zhongmei Magnesium Industry.

[0085] ZG203 is a phenol-free phosphite, a white solid with a phosphorus content of 3.5~4.1wt%, manufactured by Jiaxing Zhongcheng Environmental Protection Technology Co., Ltd.

[0086] IOTA 65803B Mica Tape with Methylphenyl Silicone Resin, pale yellow liquid, solid content 50±1wt%, drying time (160℃) ≤5min, thermal weight loss (300℃×h) ≤5%, Anhui Aiyota Silicone Oil Co., Ltd.

[0087] KJ-B01 silicone powder is a white powder with a density of 0.95 g / cm³. 3 Organosilicon content 71wt%, weight loss at 300℃ ≤0.3wt%, Jiande Kaijie Plastic Toughening Materials Co., Ltd.

[0088] Hydrotalcite has a magnesium-aluminum ratio of 4.4 and a specific surface area of ​​11 m². 2 / g, average particle size D50=0.66μm, heavy metal content<10ppm, Jiahe Chaoyang (Shandong) New Material Technology Co., Ltd.

[0089] Grade I fly ash, density 2.93 g / cm³ 3 Specific surface area 380m² 2 / kg, fineness (45μm sieve residue) is 8%, Guodian Shenneng Huayingshan Power Generation Co., Ltd. A 300-mesh filter is used to remove particles >50μm, retaining fly ash with a particle size of 10~30μm.

[0090] Preparation Example 1

[0091] Section A: Synthesis of phosphaphenanthrene-triazine-silyl diene monomers, preparation route is as follows:

[0092]

[0093] S1. 2-Vinyl-4,6-diamino-1,3,5-triazine (8.66 g, 0.06 mol), DOPO (13.0 g, 0.06 mol), and N,N-dimethylformamide (100 mL) were added to a 250 mL three-necked flask and mechanically stirred to dissolve. BHT (0.03 g) was added to prevent DOPO oxidation. The reaction system was purged with nitrogen. 0.25 g of trifluoromethanesulfonic acid was dissolved in 50 mL of N,N-dimethylformamide and added dropwise to the reaction system over 2 hours. The mixture was then stirred at a constant temperature of 110 °C in an oil bath for 7 hours. After the reaction was complete, the reaction solution was poured into 150 mL of ice water and stirred to precipitate. The precipitate was filtered. The crude product was recrystallized from toluene / cyclohexane (1:2, v / v). The pure product was dried under vacuum at 80 °C for 12 hours to obtain intermediate A1 (Mw = 353 g / mol), yield 86.3%.

[0094] S2.A1 intermediate (60 mmol) and allyloxy-tert-butyl-dimethylsilane (21.2 g, 123 mmol) were dissolved in tetrahydrofuran (150 mL), and potassium hydroxide (72 mmol) and 18-crown-6 (6 mmol) were added while stirring. The reaction system was refluxed at 80 °C for 4 h under a nitrogen atmosphere; TLC monitoring (developing solvent: petroleum ether / ethyl acetate = 4:1) was performed until the starting material spot disappeared. After the reaction solution was cooled to 10 °C, crystals were precipitated and filtered; the filter cake was washed three times with isopropanol, and the pure product was dried under vacuum at 50 °C for 12 h to obtain A-segment monomer (Mw = 662 g / mol) powder. Yield: 80.5%, purity: 98.5%.

[0095] The structure of monomer 1 in segment A was characterized using a Bruker Avance 400 MHz superconducting NMR spectrometer. Its 1H NMR spectrum (400 MHz, CDCl3) is shown below. Figure 1 .

[0096] Preparation Example 2

[0097] Monomer 2 in segment A differs from that in Preparation Example 1 in that the terminal alkenyl hydroxysilane derivative used in step S2 is 2-hydroxy-3-[3-(trimethoxysilyl)propoxy]propyl methacrylate, with a yield of 78.4%. The structure of the product (Mw=990 g / mol) is as follows:

[0098] .

[0099] The 1H NMR spectrum (400MHz, CDCl3) of monomer 2 in segment A is shown below. Figure 2 .

[0100] Preparation Example 3

[0101] Synthesis of monomer 1 in segment B: The reaction equation is as follows:

[0102]

[0103] 1) Under nitrogen protection, benzoxazole-5-ol (10.0 g, 74 mmol) and 3-vinyl-1H-pyrazole (6.96 g, 74 mmol) were dissolved in 1,2-dichloroethane (80 mL), and 2,2,6,6-tetramethylpiperidine oxide (74 mmol) and (diacetoxyiodine)benzene (148 mmol) were added. The system was stirred continuously at room temperature for 48 h. The reaction solution was washed with water (2 × 50 mL), and the organic phase was concentrated and purified by column chromatography (silica gel, eluent: dichloromethane / methanol = 20:1) to give intermediate B1 (Mw = 227 g / mol), yield 92.3%.

[0104] 2) Intermediate B1 (71 mmol) and K2CO3 (19.63 g, 0.142 mol) were added to anhydrous DMF (80 mL) and mechanically stirred for 30 min (200 rpm) to form potassium phenolate. A DMF solution (20 mL) of 2,5-dibromo-3,4-vinyldioxothiophene (10.8 g, 36 mmol) was slowly added dropwise over ~40 min to control exothermic reaction. The mixture was heated to 80 °C and reacted at this temperature for 5 h. The reaction endpoint was monitored by TLC (electrolyte: dichloromethane / petroleum ether = 3:1). After the starting material point (Rf = 0.2) completely disappeared, the mixture was cooled to room temperature, and the reaction solution was poured into 300 mL of deionized water. The precipitate was stirred and filtered. The filter cake was washed with water (3 × 50 mL) and then with cold methanol (2 × 30 mL). The crude product was recrystallized from toluene and dried under vacuum at 60 °C for 6 h to obtain solid B-segment monomer 1 (Mw = 593 g / mol), with a yield of 82.4%.

[0105] The 1H NMR spectrum results for monomer 1 in segment B are shown below. Figure 3 .

[0106] Preparation Example 4

[0107] Monomer 2 in segment B differs from preparation example 2 in that the dibromothiophene derivative used in step 2) is 2,5-dibromothiopheneno[3,2-b]thiophene. The product (Mw = 591 g / mol) had a yield of 86.2% and the structure was as follows:

[0108] .

[0109] The 1H NMR spectrum results for monomer 2 in segment B are shown below. Figure 4 .

[0110] Examples 1-4

[0111] A high-performance anti-interference fireproof cable, according to Figure 5 Preparation process as shown:

[0112] (1) Shielding layer forming: The aluminum-magnesium alloy mesh is impregnated with an aqueous solution containing 10wt% aniline hydrochloride and adsorbed at 25℃ for 30min; ammonium persulfate with the same molar amount as aniline is added dropwise and polymerized for 2h; then carbon black / N-methylpyrrolidone slurry with 40% solid content is spin-coated and cured at 3000rpm and 80℃ for 10min to form the shielding layer.

[0113] (2) Preparation of flame-retardant mica tape: 100 parts of methyl phenyl silicone resin were dissolved in xylene, 50 parts of nano-sheet aluminum hydroxide and 5 parts of polyphosphate melamine salt were added and mixed and dispersed to prepare a flame-retardant adhesive; then it was coated on the phlogopite mica tape substrate, dried and wrapped around the shielding layer to form a fireproof layer with a thickness of 0.4 mm.

[0114] (3) Synthesis of the resin matrix: CuBr (0.45 mmol), PMDETA (0.90 mmol), and ethyl 2-bromoisobutyrate (EBiB, 0.35 mmol) were mixed in γ-valerolactone (GBL, 0.2 mol). Under nitrogen protection (oxygen content < 50 ppm), monomer 1 of segment A obtained in Preparation Example 1 was added at 0.5 mL / min, the temperature was increased to 62 °C at a rate of 1.5 °C / min, and prepolymerized for 3 h at a stirring rate of 200 rpm; then monomer 1 of segment B obtained in Preparation Example 3 was added at 0.7 mL / min, the temperature was increased to 72 °C at a rate of 1.5 °C / min, and the reaction was kept at a constant temperature of 250 rpm for 4 h. The mixture was cooled in an ice-water bath, methanol was added to terminate the reaction, the product was precipitated, filtered, and the copolymer resin melt was obtained.

[0115] The resin matrix melt from step (3) was subjected to GPC testing (using THF as the mobile phase, flow rate 1.0 mL / min, column temperature 35℃, and polystyrene standard) to obtain its number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (PDI).

[0116] The intrinsic viscosity (η) was measured using an Ubbelohde viscometer (solvent: phenol-tetrachloroethane, v:v=1:1, 25°C).

[0117] Melt flow index (MI) was tested according to standard GB / T 3682.1-2018. A melt flow indexer (Tinius Olsen MP600) was used at a temperature of 190℃, a load of 2.16 kg, and a cutting interval of 15 s.

[0118] Table 1 shows the molar ratio of segments A and B and the relevant properties of the resin matrix melt in Examples 1-4.

[0119] Table 1

[0120]

[0121] (4) Preparation of outer sheath material: In a twin-screw extruder, 75wt% of the resin matrix from step (3), α-tocopherol and phosphite antioxidants are added to the main feed port, melted at 140℃ for 5min, and then magnesium hydroxide and fly ash are added in equal amounts three times; at the side feed port at an inlet temperature of 80℃, the remaining resin matrix, silicone lubricant, zinc stearate, hydrotalcite and vulcanizing agent are added; at a twin-screw speed of 300rpm, the raw materials are melted at 160℃, mixed at 175℃, and extruded and granulated at 160℃ to obtain masterbatch; the masterbatch and vulcanization accelerator are sheared and mixed, vulcanized at 170℃ and 15MPa for 10min, and cooled to room temperature at a rate of 8℃ / min to obtain outer sheath material;

[0122] The amount of each raw material used in the preparation of the outer sheath material is shown in Table 2.

[0123] Table 2 (Number of parts by weight)

[0124]

[0125] (5) Cable assembly: The conductor core layer is placed on the wire feeding frame and then continuously, uniformly and seamlessly wrapped by passing through the shielding layer braiding machine (which directly braids aluminum-magnesium alloy wire mesh onto the conductor core), the fireproof layer wrapping machine (which loads flame-retardant mica tape), and the sheath extruder.

[0126] After the wrapping is completed, the cable immediately enters the continuous vulcanization pipeline and is protected by nitrogen gas. It is first vulcanized at 150℃ and 12MPa for 5 minutes, then the temperature is increased to 170℃ and the pressure is increased to 18MPa for 10 minutes. Then, it is treated with an 80℃ hot water bath for 5 minutes, a 50℃ warm water bath for 5 minutes, and finally water-cooled at 25℃ for 10 minutes at a gradient cooling rate of 8℃ / min. The cooled cable is then placed in a 70~80℃ oven for 2~4 hours and allowed to cool naturally to room temperature before being wound into a coil.

[0127] Examples 5-7

[0128] A high-performance anti-interference fireproof cable, which differs from Example 1 in that, in step (4), the amount of each component in the cable outer sheath material is adjusted in sequence as shown in Table 3.

[0129] Table 3 (Number of parts by weight)

[0130]

[0131] Example 8

[0132] A high-performance anti-interference fireproof cable, differing from Example 1 in that, in step (3), the monomer in segment A of the resin matrix is ​​monomer 2 obtained in Preparation Example 2. The Mn of the copolymerized resin matrix is ​​10.0 × 10⁻⁶. 4 g / mol, PDI=1.33, eta=0.87dL / g, MI=18g / 10min.

[0133] Example 9

[0134] A high-performance anti-interference fireproof cable, differing from Example 1 in that, in step (3), the B-segment monomer in the resin matrix is ​​the B-segment monomer 2 obtained in Preparation Example 4. The Mn of the copolymerized resin matrix is ​​8.8 × 10⁻⁶. 4 g / mol, PDI=1.34, eta=0.94dL / g, MI=17.5g / 10min.

[0135] Comparative Example 1

[0136] A cable, differing from Example 1 in that, in step (3), the B-segment monomer in the resin matrix is ​​replaced with the B1 intermediate obtained in step (1) of Example 3; other components and their amounts remain unchanged. The resulting copolymer resin matrix has an Mn value of 7.8 × 10⁻⁶. 4 g / mol, PDI=1.68, eta=0.62dL / g, MI=22g / 10min.

[0137] Comparative Example 2

[0138] A cable, differing from Example 1 in that, in step (3), the monomer in section A of the resin matrix is ​​replaced with 1-(tert-butyldimethylsilyl)-2-propen-1-ol; the monomer in section B and other components and their amounts are the same as in Example 1. The resulting copolymer resin matrix has an Mn value of 7.5 × 10⁻⁶. 4 g / mol, PDI=1.82, eta=0.55dL / g, MI=25g / 10min.

[0139] Comparative Example 3

[0140] A cable, differing from Example 1, in that, in step (3), the resin matrix uses monomer A1 homopolymerized for 7 hours and monomer B1 homopolymerized for 4 hours, followed by physical blending; the amounts of both are the same as in Example 1. The resulting blended resin matrix has a Mn value of 10.5 / 7.2 × 10⁻⁶. 4 g / mol (bimodal), PDI=2.8, η=1.12dL / g, MI=12g / 10min.

[0141] Comparative Example 4

[0142] A high-performance anti-interference fireproof cable, which differs from Example 1 in that, in step (1), the surface of the aluminum-magnesium alloy wire braided mesh is not treated with a composite polyaniline / carbon black coating.

[0143] Comparative Example 5

[0144] A high-performance anti-interference fireproof cable, which differs from Example 1 in that the mica tape wrapping layer in step (2) does not contain nano-sheet aluminum hydroxide and polyphosphate melamine salt.

[0145] The performance of the cable outer sheath materials prepared in the examples and comparative examples was tested using the following methods:

[0146] (1) Mechanical properties: The cable outer sheath material was made into a dumbbell-shaped specimen of type 1B as specified in GB / T 1040.2-2006, with a thickness of 2.0±0.2 mm. The tensile strength and elongation at break were measured using an Instron 5967 universal testing machine at an ambient temperature of 23±2℃ and a relative humidity of 50±5% at a tensile speed of 50 mm / min. The average value of 5 specimens was taken.

[0147] (2) Performance retention rate after heat aging: GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air". The sample was placed in a heat aging chamber (Memmert UF110) at 135±2℃ and aged continuously for 168 h. After aging, the sample was conditioned at 23±2℃ for 24 h, and then the tensile strength and elongation at break were tested according to the above method. Retention rate = (performance value after aging / performance value before aging) × 100%.

[0148] (3) Flame retardant performance: The limiting oxygen index (LOI) of the cable outer sheath material sample (100mm×6mm×3.0mm) was tested using a limiting oxygen index meter (Cangzhou Zhongya).

[0149] (4) Vertical Burning (UL94): The test standard is ANSI / UL 94-2020. A sample of cable sheath material (125mm × 13.0 ± 0.5mm × 0.4mm) is placed in a vertical burning test chamber (FTT 0082). Test conditions: flame height 20mm, flame application time 2 × 10⁻⁶ s, and afterflame and afterburn time are recorded. The results determine the V-0, V-1, or V-2 rating.

[0150] (5) Carbon residue rate at 800℃: Test standard GB / T 27761-2011. Take 10±0.5 mg of outer sheath material sample, and use a simultaneous thermal analyzer (NETZSCH STA 449 F5) to heat from 30℃ to 800℃ at a rate of 10℃ / min under N2 atmosphere (flow rate 50mL / min), and hold for 5 min. Carbon residue rate = (remaining mass at 800℃ / initial mass) × 100%.

[0151] (6) Shore hardness: Refer to standard GB / T 2411-2008. A Shore hardness D tester was used, the test environment was 25℃, and the data repeatability error was ≤±1D.

[0152] The test results are shown in Table 4.

[0153] Table 4

[0154]

[0155] As shown in Tables 3 and 4, Examples 1-4 illustrate the variation of cable outer sheath material performance with the molar ratio of A and B. In the copolymer resin matrix of the cable outer sheath material, thiophene groups enhance shielding effectiveness, while phosphaphenanthrene and pyrazole groups provide flame retardant effects. Benzooxazole and siloxane coordinate the strength and toughness of the copolymer. Because the rigid rings of phosphaphenanthrene in segment A hinder chain segment movement, reducing the chain growth rate, and the uniform distribution of rigid units inhibits chain transfer, the PDI narrows. Therefore, when the proportion of segment A increases (Example 3), Mn decreases and PDI decreases (PDI=1.25), but the copolymer rigidity increases, and the tensile strength, hardness, and char residue of the outer sheath material all increase. When the proportion of segment B is higher (Example 1), MI increases and processability improves, but flame retardancy is somewhat reduced (LOI=37%). Example 8 uses A-segment monomer 2 containing more siloxane, which improves the compatibility of the copolymer chain. Because A-segment monomer 2 has a larger molecular weight, it results in increased chain rigidity at the same degree of polymerization, leading to higher Mn and higher intrinsic viscosity; the outer sheath material has higher mechanical strength. Example 9 uses B-segment monomer 2 (thieno[3,2-b]thiophene derivative). Due to the strong conjugation of the thiophene ring, the chain activity is slightly reduced, resulting in a lower Mn and slightly lower MI than in Example 1, and slightly better processability; the performance of its sheath material is comparable to that of Example 1.

[0156] In Comparative Example 1, the monomer in segment B was replaced with a small molecule (227.22 g / mol) intermediate B1. The monomer had low activity, which did not match the reactivity of segment A, resulting in poor polymerization controllability, insufficient polymer chain growth, a sharp drop in Mn, a wider distribution (PDI 1.68), and a high MI. The mechanical strength, shielding effectiveness, and flame retardancy of the cable sheath material all decreased significantly (LOI = 30%, shielding effectiveness only 45 dB).

[0157] In Comparative Example 2, segment A was replaced with a simple enol, lacking a rigid structure; its activity differed greatly from segment B, exhibiting intense chain transfer, the lowest Mn content, and the widest PDI range. Although it had good flowability, its mechanical strength and flame retardancy were severely inadequate, resulting in a soft and weak material (tensile strength = 12 MPa) and poor flame retardancy (LOI = 26%).

[0158] In addition, in Comparative Example 3, which physically blends homopolymers A and B, the homopolymer Mn in segment A is high (10.5 × 10⁻⁶). 4 g / mol), B-segment homopolymer has low Mn (7.2×10 g / mol). 4 Therefore, the blend forms a bimodal distribution with an extremely wide molecular weight distribution (PDI=2.8), poor fluidity, easy agglomeration, low MI, and phase separation. The performance of the cable deteriorates, proving the necessity of chemical block copolymerization.

[0159] Comparative Example 4, lacking a polyaniline / carbon black coating, only provided limited shielding with its sheath, resulting in a sharp drop in shielding effectiveness. Comparative Example 5, with its fire-retardant layer lacking flame retardants, showed a significant decrease in LOI (Low Index of Infrared).

[0160] Volume resistivity test of the shielding layer: refer to standard GB / T 1410-2006 (four-probe method, 25℃).

[0161] In addition, tests were conducted on all relevant aspects of the cable, using the following methods:

[0162] (1) DC resistance of conductor (Ω / km): Test standard: GB / T 3956.

[0163] (2) Shielding effectiveness (SE): Test standard GB / T 18015.1-2017. A vector network analyzer (Keysight N5222B) was used to press the cable material into a ring-shaped sample with an outer diameter of Φ113mm, an inner diameter of Φ31mm, and a thickness of 2.0mm at 170℃ and 15MPa. The test frequency range was 30MHz ~ 1.5GHz, with a focus on the shielding effectiveness value (dB) at 1.0 GHz.

[0164] (3) Salt spray resistance: The test standard GB / T 10125 is used to conduct a 1000h neutral salt spray test and calculate the change rate of volume resistivity (Δρ°).

[0165] The test results are shown in Table 5.

[0166] Table 5

[0167]

[0168] As shown in Table 5, all cable samples have the same conductor core structure, therefore their DC resistance values ​​are basically consistent. The triple shielding mechanism of metal mesh, polyaniline / carbon black coating, and conjugated polymer achieves high shielding efficiency (67-72 dB); the change rate after salt spray is low (≤3.5%), and the durability is good. Comparative Examples 1-3, due to structural defects in their copolymer monomers, have decreased shielding efficiency (55-65 dB) and increased change rate after salt spray (8-10%). Comparative Example 4 has no shielding coating, resulting in increased corrosion tendency, a sharp drop in shielding efficiency to 45 dB, and an increase in change rate to 50% after salt spray. The cable in Comparative Example 5 has normal shielding efficiency.

[0169] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-performance anti-interference fireproof cable, characterized in that: From the inside out, it includes: Conductor core layer: symmetrical star-shaped stranded structure of multi-strand tin-plated copper wire, with a stranding pitch of 8-12 times the conductor diameter; gaps are filled with zinc borate-containing fiberglass rope; Shielding layer: Aluminum-magnesium alloy wire woven mesh covering the core layer, with a weaving density of ≥90%; surface is coated with polyaniline / carbon black. Fireproof layer: A mica tape covering the shielding layer is wrapped around the surface and coated with a flame-retardant adhesive; the flame-retardant adhesive contains nano-sheet aluminum hydroxide, polyphosphate melamine salt and organosilicon resin; Outer sheath layer: by weight, it contains 65-70 parts of resin matrix component; the resin matrix is ​​copolymerized from monomers of segment A and segment B; Segment A is a phosphaphenanthrene-triazine-silyl diene monomer with a structure as shown in Formula I: (I); among which, ; Segment B is a benzoxazole-thiophene-pyrazolyl diene monomer with a structure as shown in Formula II: (II); among which, , One of Y1, Y2, Y3, and Y4 is connected to M through an oxygen atom, while the rest are H atoms.

2. The cable as described in claim 1, characterized in that, The outer sheath layer, by weight, further includes: 22-30 parts of functional filler, including: 7-10 parts of fly ash and 15-20 parts of magnesium hydroxide; Additives, 4.5-5 parts, including: 0.3-0.5 parts α-tocopherol, 0.5-0.8 parts phosphite antioxidant, 1.8-2.1 parts silicone lubricant, 0.3-0.5 parts zinc stearate, 0.1-0.3 parts hydrotalcite, 1.0-1.2 parts vulcanizing agent and 0.5-0.6 parts accelerator; The fly ash has a 45μm sieve residue of ≤10wt%, and the D50 particle size of magnesium hydroxide is 5~10μm; the vulcanizing agent is dicumyl peroxide, and the accelerator is triallyl isocyanurate.

3. The cable as described in claim 1, characterized in that: In the conductor core layer, the zinc borate loading is 8~10 wt%; The shielding layer has a polyaniline / carbon black composite coating with a thickness of 0.2~0.4mm, which is formed by in-situ polymerization and spin coating processes. The flame-retardant adhesive of the fireproof layer has a solid content of 40-50%, and its solids, by mass, include: 100 parts of organosilicon resin, 45-50 parts of nano-sheet aluminum hydroxide, and 5-8 parts of polyphosphate melamine salt. The organosilicon resin is methylphenyl silicone resin, and the specific surface area of ​​the nano-sheet aluminum hydroxide is ≥20m². 2 / g, the nitrogen content of polyphosphate melamine salt is ≥38wt%, and the phosphorus content is ≥14wt%.

4. The cable as described in claim 1, characterized in that, The monomer in segment A is synthesized via the following pathway: Under a sulfuric acid (S1) and nitrogen (N2) atmosphere, 2-vinyl-4,6-diamino-1,3,5-triazine and DOPO were reacted at a molar ratio of 1:0.99-1.05 with an acid catalyst and a phase transfer catalyst at 100-115°C for 5-8 h to obtain intermediate A1. The acid catalyst was trifluoromethanesulfonic acid, and the phase transfer catalyst was tetrabutylammonium bromide, with amounts of 0.8-1.5 wt% and 0.1-0.2 wt% of the total mass of the reactants, respectively. Under an S2-N2 atmosphere, an A1 intermediate with a molar ratio of 1:2.05-2.20 and a terminal alkenyl hydroxysilane derivative are nucleophilically substituted at 80-95°C for 3-5 hours under the catalysis of potassium hydroxide and a crown ether to obtain the A-segment monomer; the amount of potassium hydroxide used is 1.0-1.2 times the molar amount of the A1 intermediate, and the crown ether is 18-crown-6 with a molar ratio of 0.05-0.10:1 to the A1 intermediate; The terminal alkenyl hydroxysilane derivative is selected from 1-hydroxyallyltrimethylsilane, 2-hydroxy-3-[3-(trimethoxysilyl)propoxy]propyl methacrylate or allyloxy-tert-butyl-dimethylsilane.

5. The cable as described in claim 1, characterized in that, The B-segment monomer is synthesized via the following pathway: 1) Under N2 atmosphere, 1,3-benzoxazole-y-ol and vinyl-1H-pyrazole in a molar ratio of 1:0.99~1.03 reacted in a halogenated solvent in a oxidative coupling system for 45~50 h at room temperature to obtain intermediate B1, where y=4,5,6,7. The oxidative coupling system comprises 2,2,6,6-tetramethylpiperidine oxide and (diacetoxyiodine)benzene, in amounts of 1.0 to 1.2 times and 1.8 to 2.2 times the molar amount of benzoxazole-γ-ol, respectively. 2) Under N2 atmosphere, intermediate B1 and dibromothiophene derivative react at a molar ratio of 1.95~2.05 with K2CO3 catalysis at 70~85℃ for 4~6h to obtain monomer B; the amount of potassium carbonate used is 2.0~2.5 times the molar amount of intermediate B1. The dibromothiophene derivative is selected from 2,5-dibromo-3,4-vinyldioxythiophene or 2,5-dibromothiophene[3,2-b]thiophene.

6. A method for preparing the cable according to any one of claims 1 to 5, characterized in that: Includes the following steps: (1) Shielding layer forming: After in-situ polymerization of polyaniline, aluminum-magnesium alloy wire mesh is spin-coated with carbon black slurry and cured; (2) Preparation of flame-retardant mica tape: Prepare an organosilicon resin flame-retardant adhesive containing nano-sheet aluminum hydroxide and polyphosphate melamine salt; then coat it onto the mica tape substrate and dry it; (3) Synthesis of resin matrix: In the presence of an inert atmosphere and a catalyst system, the monomer of section A undergoes a first polymerization reaction at a first temperature; the temperature is increased to a second temperature at a heating rate of 1~2℃ / min, and the monomer of section B is added to carry out a second polymerization reaction; after the reaction is completed, it is terminated by an ice-water bath to obtain the resin matrix melt; (4) Preparation of outer sheath material: ① Mixing: In the twin-screw extruder, add 70~80wt% of the resin matrix from step (3), α-tocopherol and phosphite antioxidants to the main feed port, and add pretreated magnesium hydroxide and fly ash after melting; add the remaining resin matrix and other additives except for the vulcanization accelerator to the side feed port; ②Extrusion: Extrusion granulation is carried out at a twin-screw speed of 250~300rpm and a temperature gradient of 140~180℃ to obtain masterbatch; ③ Mixing: The masterbatch and vulcanization accelerator are sheared and mixed; vulcanization is performed to obtain the outer sheath material; (5) Cable assembly: The conductor core layer is sequentially covered with the shielding layer of step (1), the flame-retardant mica tape of step (2), and the outer sheath material of step (4); after step vulcanization, gradient cooling, and annealing, it is wound into a coil.

7. The method as described in claim 6, characterized in that, In step (1): the in-situ polymerization conditions of polyaniline are: impregnating the aluminum-magnesium alloy mesh with 10wt% aniline hydrochloride aqueous solution, adsorbing at 25℃ for 30min; then adding ammonium persulfate with the same molar amount as aniline, and polymerizing for 2h; the spin coating speed is 3000±1000rpm, and the curing parameters are: curing at 80℃ for 10~20min.

8. The method as described in claim 6, characterized in that, In step (3): the feeding rate of the monomer in section A is 0.5~0.7 mL / min, the time of the first polymerization reaction is 2~3 h, and the first temperature is 58~65℃; the feeding rate of the monomer in section B is 0.7~0.9 mL / min, the time of the second polymerization reaction is 3.5~4.5 h, and the second temperature is 68~75℃; The catalyst system includes an initiator, a copper salt catalyst, and a ligand, with a molar ratio of (0.7~1.0):(1.5~2.5):

1. The initiator is ethyl 2-bromoisoethylbutyrate, the copper salt catalyst is cuprous bromide, and the ligand is N,N,N',N'',N''-pentamethyldivinyltriamine.

9. The method as described in claim 6, characterized in that, In step (4): the temperature gradient of the twin-screw extruder is as follows: 140℃ in the feeding section, 150~160℃ in the melting section, 170~180℃ in the mixing section, and 160~165℃ in the extrusion section; the feeding temperature of the side feed port is ≤100℃ and the rotation speed is ≤280rpm; the vulcanization operation is carried out in a continuous vulcanization pipeline under nitrogen protection, with a temperature of 160~170℃, a pressure of 12~15MPa, a vulcanization time of 10~15min, and a cooling rate of 5~8℃ / min.

10. The method as described in claim 6, characterized in that, In step (5): the stepped vulcanization operation is as follows: after the cable is wrapped, it is sent into the continuous vulcanization pipeline and nitrogen gas is introduced for protection. First, it is vulcanized at 140~150℃ and 12~15MPa for 5 minutes, and then the temperature is raised to 160~170℃ and 15~20MPa for 8 minutes. The gradient cooling operation is as follows: after vulcanization, the vulcanization process is sequentially subjected to an 80°C hot water bath for 5 minutes, a 50°C warm water bath for 5 minutes, and finally water cooling at 25°C for 10 minutes, with a cooling rate of 5~8°C / min. The annealing process involves placing the cooled cable in an oven at 70-80°C for 2-4 hours and then allowing it to cool naturally to room temperature.

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