Highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and preparation method thereof

Abstract

The present invention belongs to the technical field of cable preparation and provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof. First, a polyrotaxane precursor powder is prepared by reacting cyclodextrin with a block copolymer. Subsequently, a multifunctional polyrotaxane powder is obtained by introducing an alkyl spacer monomer. Dioxane, a methacrylate monomer and a photoinitiator are premixed and UV-cured to form a gel-state photocurable network, and a dual-network curing is completed. The premixed network is then combined with a PU prepolymer to prepare a dual-network prepolymer. Finally, a flame retardant is compounded with a polyolefin elastomer to prepare a flame-retardant masterbatch, which is uniformly mixed with a matrix, the multifunctional polyrotaxane powder, kaolin and the dual-network prepolymer. The masterbatch is then coated on a metal conductor using an extrusion process. A composite cable with excellent flame retardancy, cold resistance and dynamic fatigue resistance is prepared through UV irradiation and a thermal curing process.

Description

Technical Field

[0001] The invention belongs to the technical field of cable preparation, and relates to a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof. Background Art

[0002] At present, with the rapid development of fields such as electricity, communications and transportation, the performance requirements for wires and cables are also increasing. Especially in extreme environments and special application scenarios, cables need to have high flame retardancy, cold resistance and excellent dynamic fatigue resistance. However, traditional cable materials often have significant limitations in meeting these performance requirements. For example, conventional flame retardant treatment methods may cause the mechanical properties of the material to decline, and it is difficult to balance the toughness and fatigue resistance of the material in low-temperature environments. In addition, the material is susceptible to fatigue damage during long-term dynamic use, resulting in performance degradation or even failure, seriously affecting its safety and service life. Chinese patent CN105551605A discloses a flame-retardant and tensile-resistant soft cable, which uses a five-layer metal armor layer. Because it is a cylindrical armor layer, its bendability is poor and the minimum bending radius is large, resulting in poor fatigue resistance. Summary of the Invention

[0003] In response to the shortcomings of the prior art, the present invention aims to provide a highly flame-retardant, cold-resistant, and dynamic fatigue-resistant composite cable and its preparation method. First, a polyrotaxane precursor powder is prepared using cyclodextrin as the core and combined with a block copolymer. A functional alkyl spacer monomer is then introduced to produce the polyrotaxane powder. Subsequently, the polyrotaxane powder is combined with a polyurethane prepolymer via a double network to form a double network prepolymer. Finally, a flame retardant is mixed with a polyolefin elastomer to prepare a flame-retardant masterbatch. This masterbatch is then uniformly mixed with a matrix material, multifunctional polyrotaxane powder, kaolin, and double network prepolymer. The masterbatch is then coated with a metal conductor using a melt extrusion process. The composite cable is then formed through ultraviolet irradiation and thermal curing to meet the needs of actual production.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof, the preparation method comprising:

[0006] S1, dispersing γ-cyclodextrin in deionized water, adjusting the pH to 7-8, adding PEG-PCL-PEG to react and obtain polyrotaxane precursor powder;

[0007] S2, dispersing the polyrotaxane precursor powder in N,N-dimethylformamide, adding a C12-C18 alkyl spacer monomer and triethylamine, and reacting to obtain a multifunctional polyrotaxane powder;

[0008] S3, mixing 1,4-dioxane, tetrahydrofuran methacrylate and a photoinitiator TPO-L, and UV pre-curing to form a gel state to obtain a photocurable network, mixing bismaleimide, diaminodiphenylmethane and N-methylpyrrolidone and adding the mixture to the photocurable network to obtain a double network material, then mixing polytetrahydrofuran diol, isophorone diisocyanate and KH-550 to obtain a PU prepolymer, crushing the double network material and mixing it with the PU prepolymer, and vacuum degassing to obtain a double network prepolymer;

[0009] S4, mixing the flame retardant with the polyolefin elastomer, extruding and water-cooling pelletizing to obtain the flame retardant masterbatch, mixing the matrix, flame retardant masterbatch, multifunctional polyrotaxane powder and kaolin, adding the double network prepolymer after the materials are melted and mixing evenly, extruding and coating the metal conductor, UV irradiating and heat curing after extrusion to obtain the core wire, sequentially coating the core wire with a shielding layer and a sheath to obtain a highly flame retardant, cold-resistant and dynamic fatigue-resistant composite cable.

[0010] Specifically include:

[0011] S1, dispersing γ-cyclodextrin in deionized water, adjusting the temperature to a first temperature, adjusting the pH to 7-8, adding PEG-PCL-PEG, maintaining the first temperature and ultrasonically stirring for reaction, filtering to remove undissolved or large particle impurities after the reaction, concentrating under reduced pressure, washing and drying to obtain a polyrotaxane precursor powder;

[0012] S2, dispersing the polyrotaxane precursor powder in N,N-dimethylformamide, adjusting the temperature to a first temperature, adding a C12-C18 alkyl spacer monomer and triethylamine, maintaining the reaction at the first temperature, and rotary evaporating after completion of the reaction, washing, and drying to obtain a multifunctional polyrotaxane powder;

[0013] S3, mixing 1,4-dioxane, tetrahydrofuran methacrylate and a photoinitiator TPO-L, UV pre-curing to form a gel state, obtaining a photocurable network, mixing bismaleimide, diaminodiphenylmethane and N-methylpyrrolidone, and adding the mixture to the photocurable network, adjusting the temperature to a second temperature for curing to obtain a double network material, then mixing polytetrahydrofuran diol, isophorone diisocyanate and KH-550, adjusting the temperature to a third temperature for reaction to obtain a PU prepolymer, crushing the double network material and mixing it with the PU prepolymer, and vacuum degassing to obtain a double network prepolymer;

[0014] S4, mixing the flame retardant with the polyolefin elastomer, extruding and water-cooling pelletizing to obtain the flame retardant masterbatch, mixing the matrix, flame retardant masterbatch, multifunctional polyrotaxane powder and kaolin, adding the double network prepolymer after the material is melted and mixing evenly, extruding and coating the metal wire, and after extrusion, subjecting the core wire to UV irradiation and thermal curing at the fourth temperature to obtain the core wire, and sequentially coating the core wire with a shielding layer and a sheath to obtain a highly flame retardant, cold-resistant and dynamic fatigue-resistant composite cable.

[0015] The cyclic cavity of γ-cyclodextrin selectively captures the hydrophobic PCL segments of the PEG-PCL-PEG triblock copolymer through hydrophobic interactions, forming a host-guest complex. The hydrophilic hydroxyl groups on the cyclodextrin's exterior form a hydrogen-bonding network with water molecules, ensuring stable dispersion of the entire system in the aqueous phase. The hydrophilic PEG segments of the copolymer extend outward, forming dynamic physical crosslinks. Ultrasonic treatment accelerates the inclusion process through cavitation, while the pH environment stabilizes the charge state of the cyclodextrin hydroxyl groups, preventing electrostatic repulsion caused by protonation from interfering with host-guest binding. In the resulting polyrotaxane structure, the cyclodextrin can slide along the polymer chains, and this entanglement imparts self-healing properties to the material. Swelling of the polyrotaxane precursor in a polar solvent exposes active hydroxyl sites on the cyclodextrin's outer edge. Long-chain alkyl spacer monomers bind to the hydroxyl groups through a nucleophilic substitution reaction. Triethylamine, as a catalyst, maintains the reaction equilibrium by neutralizing reaction byproducts and promoting the grafting of alkyl chains. The introduced C12-C18 alkyl chains form a dense outer protective layer through hydrophobic interactions and van der Waals forces, enhancing the intermolecular physical crosslink density while also regulating the sliding freedom of the cyclodextrin through steric hindrance. The hydrophobic properties of the alkyl chains reduce the surface energy of the material, while their long-chain structure provides sites for intermolecular entanglement, forming a multi-level secondary structural network. The reversible slip of the cyclodextrin along the polymer backbone within the polyrotaxane structure achieves uniform stress distribution. The weak interactions formed by the secondary physical crosslinking network, which maintains reversible dissociation at low temperatures, synergistically inhibit low-temperature crystallization through the inclusion of the PCL segments in the cyclodextrin cavity, thereby maintaining the material's low-temperature stability.

[0016] The construction of the photocurable network is based on the photoinitiated free radical polymerization mechanism of tetrahydrofuran methacrylate. Ultraviolet light irradiation induces homolytic cleavage of the photoinitiator molecules, generating reactive free radical species that trigger the reaction of the methacrylate monomer. Through the chain growth, chain transfer, and termination stages of the free radicals, a three-dimensional cross-linked network is formed. The rigid structure of the tetrahydrofuran ring imparts initial mechanical strength to the network, while the presence of ether bonds provides local segmental mobility. The subsequent introduction of bismaleimide and diaminodiphenylmethane undergoes a stepwise polymerization reaction at high temperature. The mechanism involves nucleophilic attack of the amine group on the electron-deficient double bond in the maleimide ring, forming secondary amine bonds. The covalently cross-linked network constructed during this thermal curing process exhibits dynamically reversible properties. Stress relaxation can be achieved at high temperatures through the cleavage and recombination of imine bonds, thereby forming a complementary interpenetrating structure with the rigid backbone of the photocurable network.

[0017] The synthesis of polyurethane prepolymers follows the principle of a stepwise polycondensation reaction between isocyanates and polyols. The highly reactive isocyanate groups of isophorone diisocyanate undergo nucleophilic addition with the terminal hydroxyl groups of polytetramethylene glycol, forming urethane bonds as the main chain building blocks. The introduction of KH-550 silane coupling agent anchors hydrolyzable siloxane building blocks at the polymer chain ends through a secondary reaction between its alkoxysilane groups and residual isocyanate groups. When the pulverized dual-network material is blended with the PU prepolymer, unreacted isocyanate groups in the prepolymer undergo interfacial crosslinking reactions with active hydrogens (such as amino and hydroxyl groups) in the dual-network components. Simultaneously, the hydrolysis and condensation of the siloxane groups in the presence of moisture further construct multi-scale crosslinking points. The vacuum degassing process effectively eliminates bubble defects formed at the multiphase interface due to solvent evaporation and reaction outgassing by reducing the system's viscoelastic response and interfacial tension, ensuring the internal structural continuity of the composite and forming a dual-network composite system with a gradient modulus distribution. Polytetramolecular rotational freedom of ether bond and long chain flexibility of polytetramolecular furan diol as the soft segment of PU prepolymer enable the material to maintain mechanical properties at low temperatures.

[0018] The flame-retardant masterbatch is prepared based on the melt blending compatibility mechanism of the flame retardant and polyolefin elastomer. The polyolefin molecular chains form a physical coating structure with the flame retardant particles through van der Waals forces. The phosphorus-nitrogen synergistic effect of the flame retardant works through a dual pathway: gas-phase free radical quenching and condensed phase carbonization. The phosphorus-based components decompose at high temperatures to produce phosphoric acid-based substances, promoting dehydration and carbonization. The nitrogen-based compounds release inert gases upon heating, diluting the oxygen concentration. Simultaneously, their decomposition products combine with free radicals to interrupt the combustion chain reaction. The layered silicate structure of kaolin hinders the diffusion and transport of pyrolysis products through intercalation, and secondary interactions between its surface hydroxyl groups and polyolefin segments enhance the filler-matrix interface.

[0019] The continuous phase formed after the matrix melts interpenetrates with the polyrotaxane supramolecular structure through segmental entanglement. The sliding crosslinks of the cyclodextrin dissipate mechanical stress through dynamic, reversible inclusion, while the hydrophobic interface modified with the alkyl chains forms a molecular-scale dispersion with the polyolefin segments through the principle of like dissipates like. The introduction of the dual-network prepolymer triggers multiple crosslinking reactions: unreacted isocyanate groups in the PU prepolymer undergo interfacial chain extension with the hydroxyl / amino groups of the matrix, forming a covalently bonded "bridging" structure. The hydrolysis and condensation products of the siloxane groups react with the hydroxyl groups on the kaolin surface through dehydration to construct an organic-inorganic hybrid network, significantly enhancing interfacial adhesion strength.

[0020] During the UV curing stage, residual photoinitiators reactivate unreacted double bonds, triggering free radical chain growth reactions to strengthen the surface crosslink density. The thermal curing process promotes a post-curing reaction between the urethane bonds and the maleimide-amine adduct, achieving deep crosslinking of the dual network structure. The dynamic slip properties of the polyrotaxane release internal stress concentrations through the intramolecular displacement of cyclodextrin. This multi-level structural design combines the high strength of the covalent network, the energy dissipation capacity of supramolecular interactions, and the reinforcing effect of inorganic fillers, ultimately imparting flame retardancy, low-temperature resistance, and fatigue resistance to the composite cable.

[0021] As a preferred technical solution of the present invention, in S1, the mass ratio of γ-cyclodextrin, deionized water and PEG-PCL-PEG is (400-415):1500:(300-310), for example, it can be (400.0, 401.5, 403.0, 404.5, 406.0, 407.5, 409.0, 410.5, 412.0, 413.5 or 415.0):1500:(300, 301, 302, 303, 304, 305, 306, 307, 308, 309 or 310), but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] In some optional examples, the first temperature is 60-65°C, for example, it can be 60.0°C, 60.5°C, 61.0°C, 61.5°C, 62.0°C, 62.5°C, 63.0°C, 63.5°C, 64.0°C, 64.5°C or 65.0°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] In some optional examples, the Mw of the PEG-PCL-PEG is 2500.

[0024] In some optional examples, the ultrasonic stirring reaction time is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] As a preferred technical solution of the present invention, in S2, the mass ratio of the polyrotaxane precursor powder, N,N-dimethylformamide, C12~C18 alkyl spacer monomer and triethylamine is (500-520):1500:(50-55):(5-8), for example, it can be (500, 502, 504, 506, 508, 510, 512, 514, 516, 518 or 520):1500:(50.0, 50.5, 51.0, 51.5, 52.0, 52.5, 53.0, 53.5, 54.0, 54.5 or 55.0):(5.0, 5.3, 5.6, 5.9, 6.2, 6.5, 6.8, 7.1, 7.4, 7.7 or 8.0), but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] In some optional examples, the C12-C18 alkyl spacer monomer is one or more of dodecyl glycidyl ether, hexadecyl glycidyl ether, and octadecyl glycidyl ether.

[0027] In some optional examples, the time of the first temperature reaction is 4-5h, for example, it can be 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h or 5.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] As a preferred technical solution of the present invention, in S3, the mass ratio of the 1,4-dioxane, tetrahydrofuran methacrylate and photoinitiator TPO-L is (800-820): (120-130): 2, for example, it can be (800, 802, 804, 806, 808, 810, 812, 814, 816, 818 or 820): (120, 121, 122, 123, 124, 125, 126, 127, 128, 129 or 130): 2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In some optional examples, the irradiance of the UV pre-curing is 10 mW / cm 2 , time is 60-70s.

[0030] In some optional examples, the mass ratio of the bismaleimide, diaminodiphenylmethane and N-methylpyrrolidone is (60-65): (24-27): 200, for example, it can be (60, 60.5, 61, 61.5, 62, 62.5, 63, 63.5, 64, 64.5 or 65): (24, 24.3, 24.6, 24.9, 25.2, 25.5, 25.8, 26.1, 26.4, 26.7 or 27): 200, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] In some optional examples, the second temperature is 120-130°C, for example, it can be 120°C, 121°C, 122°C, 123°C, 124°C, 125°C, 126°C, 127°C, 128°C, 129°C or 130°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In some optional examples, the second temperature curing time is 2-3h, for example, it can be 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In some optional examples, the mass ratio of the polytetramethylene glycol, isophorone diisocyanate and KH-550 is (200-210): (45-50): 5, for example, it can be (200, 201, 202, 203, 204, 205, 206, 207, 208, 209 or 210): (45.0, 45.5, 46.0, 46.5, 47.0, 47.5, 48.0, 48.5, 49.0, 49.5 or 50.0): 5, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] In some optional examples, the third temperature is 70-75°C, for example, it can be 70.0°C, 70.5°C, 71.0°C, 71.5°C, 72.0°C, 72.5°C, 73.0°C, 73.5°C, 74.0°C, 74.5°C or 75.0°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] In some optional examples, the time of the third temperature reaction is 4-5h, for example, it can be 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h or 5.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In some optional examples, the mass ratio of the dual network material to the PU prepolymer is 1:1.

[0037] In some optional examples, the vacuum degassing time is 7-8h, for example, it can be 7.0h, 7.1h, 7.2h, 7.3h, 7.4h, 7.5h, 7.6h, 7.7h, 7.8h, 7.9h or 8.0h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] As a preferred technical solution of the present invention, in S4, the flame retardant is one or more of ammonium polyphosphate, pentaerythritol, and melamine.

[0039] In some optional examples, the mass ratio of the flame retardant to the polyolefin elastomer is 30:(15-20), for example, it can be 30:(15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5 or 20.0), but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] In some optional examples, the mass ratio of the matrix, flame retardant masterbatch, multifunctional polyrotaxane powder, kaolin and double network prepolymer is (100-110): (30-35): (6-10): (3-4): (5-8), for example, it can be (100-110): (30.0, 30.5, 31.0, 31.5, 32.0, 32.5, 33.0, 33.5, 34.0, 34.5 or 35.0): (6.0, 6.4, 6.8, 7.2, 7.6, 8.0, 8.4, 8.8, 9.2, 9.6 or 10.0): (3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4.0): (5.0, 5.3, 5.6, 5.9, 6.2, 6.5, 6.8, 7.1, 7.4, 7.7 or 8.0), but are not limited to the listed values, other values ​​not listed within the numerical range are also applicable.

[0041] In some optional examples, the matrix is ​​a hydrogenated styrene-butadiene block copolymer.

[0042] In some optional examples, the D50 of the kaolin is 3-5 μm, for example, it can be 3.0 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4.0 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm or 5.0 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] In some optional embodiments, the irradiance of the UV irradiation is 30 mW / cm 2 , time is 60-70s.

[0044] In some optional examples, the fourth temperature is 100-110°C, for example, it can be 100°C, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C, 109°C or 110°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] In some optional examples, the thermal curing time is 30-40 minutes, for example, it can be 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes or 40 minutes, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In a second aspect, the present invention provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable prepared by the preparation method described in the first aspect.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) through the synergistic effect of the sliding cross-linking points of the polyrotaxane supramolecular structure and the double network covalent cross-linking, the reversible slip of cyclodextrin along the polymer chain gives the material dynamic stress relaxation ability, and the interpenetrating covalent network formed by light / thermal dual curing provides rigid support, thereby improving the material's resistance to dynamic fatigue; (2) by utilizing the secondary cross-linking reaction of the organic-inorganic hybrid interface mediated by the silane coupling agent and the PU prepolymer, a multi-level sub-interface reinforcement system from molecular-level chemical bonding to micron-level mechanical interlocking is constructed, and the gradient distribution of the rigid dispersed phase of kaolin sheets and the flexible phase of polyrotaxane improves the fracture toughness; (3) the molecular synergistic design of the phosphorus-nitrogen flame retardant and the polyrotaxane molecular structure couples the condensed phase carbonization process with the dynamic cross-linking network reorganization process, while achieving high-efficiency flame retardancy, the molecular bearing effect of the cyclodextrin cavity maintains the chain segment movement ability at low temperature, thereby improving the problem of low-temperature embrittlement. DETAILED DESCRIPTION

[0048] The technical solutions of the present invention are described in detail below with reference to specific embodiments. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein.

[0049] The chemical reagents used in the examples and comparative examples of the present invention are all commercially available products and have not been subjected to any further purification treatment.

[0050] Example 1

[0051] This embodiment provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0052] S1, dispersing 400 parts of γ-cyclodextrin in 1500 parts of deionized water, adjusting the temperature to 60°C and the pH to 7, adding 300 parts of PEG-PCL-PEG, wherein the Mw of the PEG-PCL-PEG is about 2500, maintaining ultrasonic stirring at 60°C for 2 hours, filtering to remove undissolved or large particles after the reaction, concentrating under reduced pressure, washing and drying to obtain a polyrotaxane precursor powder;

[0053] S2, dispersing 500 parts of polyrotaxane precursor powder in 1500 g of N,N-dimethylformamide, adjusting the temperature to 60°C, adding 50 g of C12-C18 alkyl spacer monomer and 5 g of triethylamine, maintaining the temperature at 60°C for 4 h, and after completion of the reaction, rotary evaporation, washing, and drying to obtain a multifunctional polyrotaxane powder;

[0054] S3, 800 parts of 1,4-dioxane, 120 parts of tetrahydrofuran methacrylate and 2 parts of photoinitiator TPO-L were mixed and UV pre-cured to form a gel state. The irradiance of the UV pre-curing was 10 mW / cm 2 , time is 60s, to obtain a light-cured network, 60 parts of bismaleimide, 24 parts of diaminodiphenylmethane and 200 parts of N-methylpyrrolidone are mixed and added to the light-cured network, the temperature is adjusted to 120°C for curing for 2h to obtain a double network material, then 200 parts of polytetramethylene glycol, 45 parts of isophorone diisocyanate and 5 parts of KH-550 are mixed, the temperature is adjusted to 70°C for reaction for 4h to obtain a PU prepolymer, 100 parts of the double network material are crushed and mixed with 100 parts of the PU prepolymer, and vacuum degassing is performed for 7h to obtain a double network prepolymer;

[0055] S4, 30 parts of flame retardant and 15 parts of polyolefin elastomer are mixed, extruded and water-cooled to obtain flame retardant masterbatch, 100 parts of matrix, 30 parts of flame retardant masterbatch, 6 parts of multifunctional polyrotaxane powder and 3 parts of kaolin are mixed, 5 parts of double network prepolymer are added after the materials are melted and mixed evenly, and the metal wire is coated by extrusion, and after extrusion, it is subjected to UV irradiation and heat curing at 100°C for 30 minutes, and the irradiation intensity of the UV irradiation is 30mW / cm 2 , the time is 60s, the core wire is obtained, and the shielding layer and the sheath are coated on the surface of the core wire in sequence to obtain a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable.

[0056] Example 2

[0057] This embodiment provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0058] S1, dispersing 415 parts of γ-cyclodextrin in 1500 parts of deionized water, adjusting the temperature to 65°C and the pH to 7.5, adding 310 parts of PEG-PCL-PEG, wherein the PEG-PCL-PEG has an Mw of 2500, maintaining ultrasonic stirring at 65°C for 2.4 hours, filtering to remove undissolved or large particles after the reaction, concentrating under reduced pressure, washing, and drying to obtain a polyrotaxane precursor powder;

[0059] S2, 520 parts of polyrotaxane precursor powder were dispersed in 1500 g of N,N-dimethylformamide, the temperature was adjusted to 65°C, 55 g of C12-C18 alkyl spacer monomer and 5 g of triethylamine were added, and the reaction was maintained at 65°C for 4.3 h. After the reaction, the multifunctional polyrotaxane powder was obtained by rotary evaporation, washing and drying;

[0060] S3, 820 parts of 1,4-dioxane, 122 parts of tetrahydrofuran methacrylate and 2 parts of photoinitiator TPO-L were mixed and UV pre-cured to form a gel state. The irradiance of the UV pre-curing was 10 mW / cm 2 , time is 66s, to obtain a light-cured network, 65 parts of bismaleimide, 27 parts of diaminodiphenylmethane and 200 parts of N-methylpyrrolidone are mixed and added to the light-cured network, the temperature is adjusted to 124°C and cured for 2.3h to obtain a double network material, then 210 parts of polytetramethylene glycol, 50 parts of isophorone diisocyanate and 5 parts of KH-550 are mixed, the temperature is adjusted to 72°C and reacted for 4.2h to obtain a PU prepolymer, 100 parts of the double network material are crushed and mixed with 100 parts of the PU prepolymer, and vacuum degassing is performed for 7.3h to obtain a double network prepolymer;

[0061] S4, 30 parts of flame retardant and 20 parts of polyolefin elastomer are mixed, extruded and water-cooled to obtain flame retardant masterbatch, 110 parts of matrix, 35 parts of flame retardant masterbatch, 10 parts of multifunctional polyrotaxane powder and 4 parts of kaolin are mixed, 8 parts of double network prepolymer are added after the materials are melted and mixed evenly, and the metal wire is extruded and coated, and after extrusion, it is subjected to UV irradiation and heat curing at 103°C for 40 minutes, and the irradiation intensity of the UV irradiation is 30mW / cm 2 , the time is 62s, and the core wire is obtained. The shielding layer and the sheath are sequentially coated on the surface of the core wire to obtain a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable.

[0062] Example 3

[0063] This embodiment provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0064] S1, dispersing 410 parts of γ-cyclodextrin in 1500 parts of deionized water, adjusting the temperature to 63°C and the pH to 8, adding 302 parts of PEG-PCL-PEG, wherein the PEG-PCL-PEG has an Mw of 2500, maintaining ultrasonic stirring at 63°C for 3 hours, filtering to remove undissolved or large particles after the reaction, concentrating under reduced pressure, washing and drying to obtain a polyrotaxane precursor powder;

[0065] S2, 510 parts of polyrotaxane precursor powder were dispersed in 1500 g of N,N-dimethylformamide, the temperature was adjusted to 61°C, 51 g of C12-C18 alkyl spacer monomer and 5 g of triethylamine were added, and the reaction was maintained at 61°C for 5 h. After the reaction, the multifunctional polyrotaxane powder was obtained by rotary evaporation, washing, and drying.

[0066] S3, 815 parts of 1,4-dioxane, 130 parts of tetrahydrofuran methacrylate and 2 parts of photoinitiator TPO-L were mixed and UV pre-cured to form a gel state. The irradiance of the UV pre-curing was 10 mW / cm 2 , time is 70s, to obtain a light-cured network, 62 parts of bismaleimide, 25 parts of diaminodiphenylmethane and 200 parts of N-methylpyrrolidone are mixed and added to the light-cured network, the temperature is adjusted to 130°C for curing for 3 hours to obtain a double network material, and then 203 parts of polytetramethylene glycol, 49 parts of isophorone diisocyanate and 5 parts of KH-550 are mixed, the temperature is adjusted to 74°C and reacted for 5 hours to obtain a PU prepolymer, 100 parts of the double network material are crushed and mixed with 100 parts of the PU prepolymer, and vacuum degassing is performed for 7.7 hours to obtain a double network prepolymer;

[0067] S4, 30 parts of flame retardant and 17 parts of polyolefin elastomer are mixed, extruded and water-cooled to obtain flame retardant masterbatch, 103 parts of matrix, 33 parts of flame retardant masterbatch, 7 parts of multifunctional polyrotaxane powder and 3.3 parts of kaolin are mixed, 6 parts of double network prepolymer are added after the materials are melted and mixed evenly, and the metal wire is extruded and coated, and after extrusion, it is subjected to UV irradiation and heat curing at 110°C for 33 minutes, and the irradiation intensity of the UV irradiation is 30mW / cm 2 , the time is 70s, the core wire is obtained, and the shielding layer and the sheath are coated on the surface of the core wire in sequence to obtain a highly flame retardant, cold-resistant and dynamic fatigue-resistant composite cable.

[0068] Example 4

[0069] This embodiment provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof, wherein the preparation method specifically comprises the following steps:

[0070] S1, dispersing 405 parts of γ-cyclodextrin in 1500 parts of deionized water, adjusting the temperature to 61°C and the pH to 7.3, adding 307 parts of PEG-PCL-PEG, wherein the PEG-PCL-PEG has an Mw of 2500, maintaining ultrasonic stirring at 61°C for 2.7 hours, filtering to remove undissolved or large particles after the reaction, concentrating under reduced pressure, washing, and drying to obtain a polyrotaxane precursor powder;

[0071] S2, 515 parts of polyrotaxane precursor powder were dispersed in 1500 g of N,N-dimethylformamide, the temperature was adjusted to 63°C, 54 g of C12-C18 alkyl spacer monomer and 5 g of triethylamine were added, and the reaction was maintained at 63°C for 4.8 h. After the reaction, the multifunctional polyrotaxane powder was obtained by rotary evaporation, washing and drying.

[0072] S3, 805 parts of 1,4-dioxane, 126 parts of tetrahydrofuran methacrylate and 2 parts of photoinitiator TPO-L were mixed and UV pre-cured to form a gel state. The irradiance of the UV pre-curing was 10 mW / cm 2 , time is 63s, to obtain a light-cured network, 64 parts of bismaleimide, 26 parts of diaminodiphenylmethane and 200 parts of N-methylpyrrolidone are mixed and added to the light-cured network, the temperature is adjusted to 128°C and cured for 2.6 hours to obtain a double network material, then 208 parts of polytetramethylene glycol, 46 parts of isophorone diisocyanate and 5 parts of KH-550 are mixed, the temperature is adjusted to 75°C and reacted for 4.6 hours to obtain a PU prepolymer, 100 parts of the double network material are crushed and mixed with 100 parts of the PU prepolymer, and vacuum degassing is performed for 8 hours to obtain a double network prepolymer;

[0073] S4, 30 parts of flame retardant and 19 parts of polyolefin elastomer are mixed, extruded and water-cooled to obtain flame retardant masterbatch, 105 parts of matrix, 31 parts of flame retardant masterbatch, 9 parts of multifunctional polyrotaxane powder and 3.5 parts of kaolin are mixed, 7 parts of double network prepolymer are added after the materials are melted and mixed evenly, and the metal wire is extruded and coated, and after extrusion, it is UV irradiated and thermally cured at 108°C for 37 minutes, and the irradiation intensity of the UV irradiation is 30mW / cm 2 , the time is 67s, and the core wire is obtained. The shielding layer and the sheath are sequentially coated on the surface of the core wire to obtain a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable.

[0074] Comparative Example 1

[0075] This comparative example provides a highly flame-retardant, cold-resistant, and dynamic fatigue-resistant composite cable and a preparation method thereof. The difference between this comparative example and Example 1 is that the mass fraction of the multifunctional polyrotaxane powder in S4 is 0, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0076] Comparative Example 2

[0077] This comparative example provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof. The difference between it and Example 1 is that the mass fraction of the double network prepolymer in S4 is 0, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0078] Comparative Example 3

[0079] This comparative example provides a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable and a preparation method thereof. The difference between it and Example 1 is that the mass fraction of the flame-retardant masterbatch in S4 is 5, and the other process parameters and operating conditions are exactly the same as those in Example 1.

[0080] The flame retardancy test method is GB / T 2408-2021; the room temperature cable elongation at break is tested according to ASTM D412. Cold resistance is tested by exposing the cable to a -20°C environment for 24 hours, followed by elongation at break according to ASTM D412. Dynamic fatigue resistance is tested using the TH-5813 drag chain bending tester. The test requirements are: a frequency of 80 cycles / minute, a bend radius of 48mm, a test length of 1 meter, a minimum of 10 million bends, a temperature of 20±10°C, and a humidity of 60±20%. After the test, the core wire is considered qualified if it appears to be in good condition and free of damage. The test results are shown in Table 1.

[0081] Table 1 Test results of highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cables of Examples 1 to 4 and Comparative Examples 1 to 3

[0082]

[0083] As shown in Table 1, compared to Example 1, the flame retardant properties of Comparative Example 1 remain unchanged, but the low-temperature resistance and dynamic fatigue resistance decrease. The flame retardant properties of Comparative Example 2 remain unchanged, but the low-temperature resistance and dynamic fatigue resistance decrease. The flame retardant properties, low-temperature resistance, and dynamic fatigue resistance of Comparative Example 3 decrease. This is because the multifunctional polyrotaxane powder in Comparative Example 1 contains zero parts by weight, which eliminates the dynamic slip mechanism and prevents stress concentration from being dispersed, resulting in reduced ductility and dynamic fatigue resistance. Furthermore, the lack of inclusion complexation of the PCL segments by the cyclodextrin cavity synergistically inhibits low-temperature crystallization, leading to reduced low-temperature resistance. In Comparative Example 2, the polyurethane segments in the dual-network prepolymer provide flexibility and fracture resistance, resulting in a decrease in elongation at break. The flexible segments in the prepolymer (such as polytetrahydrofuran diol) effectively enhance the material's flexibility and brittleness resistance at low temperatures. Their absence makes the material more brittle at low temperatures, resulting in a decrease in low-temperature elongation at break. In Comparative Example 3, the flame retardant masterbatch is insufficient, the flame retardant ability of the cable is reduced, and the flame retardant masterbatch contains polyolefin elastomer, which leads to a decrease in elongation at break and dynamic fatigue resistance.

[0084] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable, characterized in that: The preparation method comprises: S1, dispersing γ-cyclodextrin in deionized water, adjusting the pH to 7-8, adding PEG-PCL-PEG to react and obtain polyrotaxane precursor powder; S2, dispersing the polyrotaxane precursor powder in N,N-dimethylformamide, adding a C12-C18 alkyl spacer monomer and triethylamine, and reacting to obtain a multifunctional polyrotaxane powder; S3, mixing 1,4-dioxane, tetrahydrofuran methacrylate and a photoinitiator TPO-L, and UV pre-curing to form a gel state to obtain a photocurable network, mixing bismaleimide, diaminodiphenylmethane and N-methylpyrrolidone and adding the mixture to the photocurable network to obtain a double network material, then mixing polytetrahydrofuran diol, isophorone diisocyanate and KH-550 to obtain a PU prepolymer, crushing the double network material and mixing it with the PU prepolymer, and vacuum degassing to obtain a double network prepolymer; S4, mixing a flame retardant with a polyolefin elastomer, extruding and water-cooling pelletizing to obtain a flame retardant masterbatch, mixing the matrix, flame retardant masterbatch, multifunctional polyrotaxane powder and kaolin, adding a double network prepolymer after the materials are melted and mixing evenly, extruding and coating a metal conductor, and subjecting the core wire to UV irradiation and heat curing after extrusion to obtain a core wire, and sequentially coating the core wire with a shielding layer and a sheath to obtain a highly flame retardant, cold-resistant and dynamic fatigue-resistant composite cable; The C12-C18 alkyl spacer monomer is one or more of dodecyl glycidyl ether, hexadecyl glycidyl ether, and octadecyl glycidyl ether.

2. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S1, The mass ratio of γ-cyclodextrin, deionized water and PEG-PCL-PEG is (400-415):1500:(300-310); The Mw of the PEG-PCL-PEG was approximately 2500.

3. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S2, The mass ratio of the polyrotaxane precursor powder, N,N-dimethylformamide, C12-C18 alkyl spacer monomer and triethylamine is (500-520):1500:(50-55):(5-8).

4. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S3, The mass ratio of 1,4-dioxane, tetrahydrofuran methacrylate and photoinitiator TPO-L is (800-820): (120-130): 2; The irradiance of the UV pre-curing is 10mW / cm 2 , time is 60-70s.

5. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S3, The mass ratio of the bismaleimide, diaminodiphenylmethane and N-methylpyrrolidone is (60-65): (24-27):

200.

6. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S3, The mass ratio of polytetramethylene glycol, isophorone diisocyanate and KH-550 is (200-210): (45-50): 5; The mass ratio of the dual network material to the PU prepolymer is 1:

1.

7. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S4, The flame retardant is one or more of ammonium polyphosphate, pentaerythritol, and melamine; The mass ratio of the flame retardant to the polyolefin elastomer is 30:(15-20).

8. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: In S4, The mass ratio of the matrix, flame retardant masterbatch, multifunctional polyrotaxane powder, kaolin and double network prepolymer is (100-110): (30-35): (6-10): (3-4): (5-8).

9. The method for preparing a highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable according to claim 1, characterized in that: S4 in The matrix is ​​a hydrogenated styrene-butadiene block copolymer; The D50 of the kaolin is 3-5 μm; The irradiance of the UV irradiation is 30 mW / cm 2 , time is 60-70s.

10. A highly flame-retardant, cold-resistant and dynamic fatigue-resistant composite cable obtained by the preparation method according to any one of claims 1 to 9.

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