A modified polydodecanolactam, a process for its preparation and a cable insulation material

Abstract

This invention relates to the field of insulating materials technology, and discloses a modified polydodecanoic acid (PCA) and its preparation method, as well as a cable insulation material. The invention provides a method for preparing the modified PCA. First, hydroxylated boron nitride is reacted with phenylsilane and hydroxyl silicone oil to construct an "inorganic boron nitride-rigid phenylsilane-flexible siloxane long chain" cross-linked coating network, yielding modified boron nitride. Then, using PCA as a matrix, modified boron nitride, a heat stabilizer, and an antioxidant are added, and the mixture is blended to obtain a modified PCA composite material. This invention uses modified boron nitride to coat PCA, forming a barrier structure that extends the penetration path of small molecules under humid heat, reducing the overall thermo-oxidative reaction rate. Combined with the heat stabilizer and antioxidant, it inhibits the thermo-oxidative cracking of amide bonds in PCA. The synergistic effect of these three agents constructs a high-temperature stable and full-temperature-range antioxidant system, effectively inhibiting the high-temperature thermo-oxidative degradation of PCA and significantly improving the material's high-temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of insulating materials technology, specifically to a modified polydodecanoic acid, its preparation method, and cable insulation materials. Background Technology

[0002] Electric wires and cables are carriers of signals, characterized by internal conductivity and external insulation. To adapt to all-weather outdoor environments and conditions where cables generate slight heat, insulating materials are typically added to electric wires and cables to protect the conductors, shielding layers, and other internal structures, while also preventing electric shock to users. Furthermore, the insulating material must be able to protect the inner and outer conductors and insulation layers of the cable from the effects of the environment, climate, hydrolysis, and physical damage.

[0003] In existing technologies, the insulation materials for wires and cables mainly include polyvinyl chloride, polyethylene, thermoplastic styrene block copolymers, cross-linked polyolefins, and silicone rubber. Among them, hydrogenated styrene-ethylene-butene-styrene block copolymer (SEBS) is a core substrate of thermoplastic styrene block copolymers. It has advantages such as good tensile strength, excellent resilience, low temperature resistance, high flexibility, high insulation, and aging resistance. However, it has poor high temperature resistance. When the ambient temperature is high, the cable insulation is easily deformed by heat or even degraded, losing its protective function and greatly increasing the safety and functional risks.

[0004] Therefore, how to optimize and adjust insulating materials to improve their high-temperature resistance is one of the technical problems that urgently need to be solved in this field. Summary of the Invention

[0005] This invention provides a method for preparing modified polydodecanoic acid to solve the problem of poor high-temperature resistance of existing insulating materials.

[0006] In a first aspect, the present invention provides a method for preparing modified polydodecanoic acid, comprising the following steps: (1) Hydroxylated boron nitride, phenylsilane and hydroxyl silicone oil are reacted to obtain modified boron nitride; (2) The modified boron nitride, polydodecanoic acid, first antioxidant and heat stabilizer are mixed and then subjected to first extrusion granulation to obtain the modified polydodecanoic acid.

[0007] In one optional embodiment, the mass ratio of the hydroxylated boron nitride, the phenylsilane, and the hydroxyl silicone oil is 100:0.5-1:0.5-1.

[0008] In one optional embodiment, the mass ratio of the modified boron nitride, the polydodecanoic acid, the first antioxidant, and the heat stabilizer is 5:90-98:0.4-1:0.4-1.1.

[0009] In one optional embodiment, the phenylsilane includes at least one of phenyltrimethoxysilane, phenyltriethoxysilane, and diphenyldimethoxysilane.

[0010] In one alternative embodiment, the first antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and tris[2,4-di-tert-butylphenyl]phosphite.

[0011] In one optional embodiment, the heat stabilizer comprises cuprous iodide and potassium iodide; optionally, the mass ratio of cuprous iodide to potassium iodide is 1:5-15.

[0012] In an optional embodiment, step (2) further includes adding a first lubricant; optionally, the first lubricant includes at least one of ethylene bis-stearamide, pentaerythritol stearate, glyceryl monostearate, and polyethylene wax; the mass ratio of the modified boron nitride to the first lubricant is 5:0.2-0.5.

[0013] In one optional embodiment, the method for preparing the hydroxylated boron nitride includes: sintering boron nitride to obtain it.

[0014] In one optional embodiment, the sintering temperature is 500℃-600℃ and the time is 1h-2h.

[0015] In one optional embodiment, the reaction temperature is 60°C-80°C and the time is 2.5h-3.5h.

[0016] In one optional embodiment, the mixing temperature is 30°C-40°C and the time is 8 min-15 min.

[0017] In one optional embodiment, in the first extrusion granulation step, the feeding frequency is 20Hz-35Hz, the extrusion temperature is successively 160℃-180℃, 200℃-215℃, 215-225℃, 225-235℃, 220℃-230℃, and the die head temperature is 220℃-230℃.

[0018] In a second aspect, the present invention provides a modified polydodecanoic acid, prepared by the preparation method described in the first aspect.

[0019] Thirdly, the present invention provides the application of modified polydodecanoic acid prepared by the preparation method described in the first aspect or the modified polydodecanoic acid described in the second aspect in cable insulation materials.

[0020] Fourthly, the present invention provides a cable insulation material, comprising, by weight, the raw materials of the cable insulation material comprising: 34-50 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer, 5-30 parts of polyphenylene ether, 5-20 parts of modified polydodecyl lactam, 5-10 parts of compatibilizer, 5-30 parts of filler oil, 3-6 parts of flow modifier, 0.5-1 part of second antioxidant, and 0.3-0.8 parts of second lubricant; The modified polydodecanoic acid is the modified polydodecanoic acid prepared by the preparation method described in the first aspect or the modified polydodecanoic acid described in the second aspect.

[0021] In one alternative embodiment, the structure of the hydrogenated styrene-ethylene-butene-styrene block copolymer includes at least one of linear and star-shaped structures.

[0022] In one alternative embodiment, in the hydrogenated styrene-ethylene-butene-styrene block copolymer, the mass fraction of styrene structural units is 30%-35%, and the mass fraction of ethylene-butene structural units is 65%-70%.

[0023] In one alternative embodiment, the hydrogenated styrene-ethylene-butene-styrene block copolymer has an elongation of 400%-800% and a Shore A hardness of 70-80.

[0024] In one alternative embodiment, the polyphenylene ether has a molecular weight of 30,000 g / mol to 50,000 g / mol.

[0025] In one alternative embodiment, the compatibilizer comprises at least one of an oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer and a non-oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer.

[0026] In one alternative embodiment, the filler oil includes at least one of naphthenic oil and paraffin oil.

[0027] In one alternative embodiment, the flow modifier comprises a silicone masterbatch supported on a polypropylene carrier.

[0028] In one alternative embodiment, the second lubricant comprises at least one of stearic acid, calcium stearate, magnesium stearate, and polyethylene wax.

[0029] In one alternative embodiment, the second antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl]phosphite, and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0030] In an alternative implementation, a flame retardant is also included.

[0031] In one alternative embodiment, the flame retardant includes at least one of magnesium hydroxide, aluminum diethylphosphite, and intumescent flame retardants.

[0032] In one optional embodiment, the intumescent flame retardant comprises, by weight, 25-35 parts of melamine polyphosphate, 5-15 parts of pentaerythritol, and 15-25 parts of aluminum magnesium hydrotalcite.

[0033] In one alternative embodiment, when the flame retardant is magnesium hydroxide, an anti-dripping agent is also included.

[0034] In one alternative embodiment, the anti-dripping agent comprises polytetrafluoroethylene.

[0035] In one optional embodiment, the anti-dripping agent is present in 2-4 parts by weight.

[0036] In one optional embodiment, the flame retardant is present in 10-35 parts by weight.

[0037] Fifthly, the present invention provides a method for preparing the cable insulation material described in the fourth aspect, comprising the following steps: The raw materials for the cable insulation material are mixed and then subjected to a second extrusion granulation process to obtain the cable insulation material.

[0038] In one optional embodiment, in the second extrusion granulation step, the feeding frequency is 20Hz-35Hz, the extrusion temperature is successively 170℃-190℃, 210℃-220℃, 220℃-230℃, 230℃-240℃, 220℃-230℃, and the die head temperature is 220℃-230℃.

[0039] The technical solution of this invention has the following advantages: 1. The method for preparing modified polydodecanoic acid provided by the present invention includes the following steps: (1) reacting hydroxylated boron nitride, phenylsilane and hydroxyl silicone oil to obtain modified boron nitride; (2) mixing the modified boron nitride, polydodecanoic acid, a first antioxidant and a heat stabilizer and then performing a first extrusion granulation to obtain the modified polydodecanoic acid. Phenylsilane is first hydrolyzed to generate phenylsilanol. The highly reactive silanol groups then undergo dehydration condensation with the B-OH groups on the surface of hydroxylated boron nitride, firmly grafting onto the powder surface via BO-Si covalent bonds. This achieves the sealing of active hydroxyl groups and the functionalization of heat-resistant phenyl groups. Simultaneously, residual silanol groups from phenylsilane and hydroxylated boron nitride can co-condense with the hydroxyl groups at both ends of the hydroxyl silicone oil, constructing an "inorganic boron nitride-rigid phenylsilane-flexible siloxane long chain" cross-linked coating network. Modified layered boron nitride sheets cross-link and coat the interior of polydodecanoic acid, forming a barrier structure that prolongs the penetration pathways of oxygen and humid small molecules, reducing the overall thermo-oxidative reaction rate of the matrix and improving the heat resistance of polydodecanoic acid. Furthermore, the high thermal conductivity of boron nitride can disperse local hot spots, reduce internal temperature differences, prevent molecular chain breakage caused by localized overheating, and slow down the thermal aging process of polydodecanoic acid.

[0040] 2. The method for preparing modified polydodecanoic acid provided by the present invention specifies that the heat stabilizer includes cuprous iodide and potassium iodide, which inhibits the deep thermo-oxidative cracking of amide bonds in polydodecanoic acid, improves the long-term thermo-oxidative aging of polydodecanoic acid, and makes up for the high-temperature stability that pure antioxidants cannot achieve.

[0041] 3. The cable insulation material provided by this invention comprises, by weight, 34-50 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer, 5-30 parts of polyphenylene ether, 5-20 parts of modified polydodecanoic acid, 5-10 parts of compatibilizer, 5-30 parts of filler oil, 3-6 parts of flow modifier, 0.5-1 part of second antioxidant, and 0.3-0.8 parts of second lubricant. Modified polydodecanoic acid can improve the problems of high-temperature deformation and large creep in the SEBS / PPO system, and provide high-strength structural support at high temperatures. During thermal aging, the heat stabilizer can synergistically inhibit the thermal degradation of SEBS and PPO during high-temperature processing and long-term use, thereby reducing the problems of molecular weight decrease, dielectric property decrease, discoloration, brittleness, and mechanical attenuation during long-term thermal aging, and thus improving the high-temperature resistance of the cable insulation material.

[0042] 3. The method for preparing cable insulation material provided by this invention completely eliminates halogen dependence and achieves zero halogen, low smoke, and low toxicity. Detailed Implementation

[0043] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0044] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0045] In existing technologies, the insulation materials for wires and cables mainly include polyvinyl chloride, polyethylene, thermoplastic styrene block copolymers, cross-linked polyolefins, and silicone rubber. Among them, hydrogenated styrene-ethylene-butene-styrene block copolymer (SEBS) is a core substrate of thermoplastic styrene block copolymers. It has advantages such as good tensile strength, excellent resilience, low temperature resistance, high flexibility, high insulation, and aging resistance. However, it has poor high temperature resistance. When the ambient temperature is high, the cable insulation is easily deformed by heat or even degraded, losing its protective function and greatly increasing the safety and functional risks.

[0046] To address the aforementioned problems, in a first aspect, a method for preparing modified polydodecanoic acid is provided, comprising the following steps: (1) Hydroxylated boron nitride, phenylsilane and hydroxyl silicone oil are reacted to obtain modified boron nitride; (2) The modified boron nitride, polydodecanoic acid (PA12), first antioxidant and heat stabilizer are mixed and then subjected to first extrusion granulation to obtain the modified polydodecanoic acid.

[0047] It should be noted that boron nitride has high thermal conductivity, which can disperse local hot spots, reduce internal temperature differences in the material, avoid molecular chain breakage caused by local overheating, and delay the thermal aging process of polydodecanoic acid; the primary antioxidant can block the chain reaction of peroxides at medium temperature; the heat stabilizer can inhibit the deep thermal-oxidative decomposition of amide bonds in polydodecanoic acid, improve the long-term thermal-oxidative aging of polydodecanoic acid, and compensate for the high-temperature stability that cannot be achieved by antioxidants alone; the three work together to construct a high-temperature stable and full-temperature-range antioxidant system, which significantly improves the high-temperature resistance of polydodecanoic acid.

[0048] The modified polydodecanoic acid prepared by this invention has the advantages of resistance to oil, alkali, acid, and fuel oil, as well as excellent electrical insulation, low temperature resistance, impact resistance, toughness, wear resistance, flowability, and wide molding temperature range. It can be widely used in cable insulation, optical fiber, chemical pipelines and other fields.

[0049] In one optional embodiment, the mass ratio of the hydroxylated boron nitride, the phenylsilane, and the hydroxyl silicone oil is 100:0.5-1:0.5-1.

[0050] In one optional embodiment, the mass ratio of the modified boron nitride, the polydodecanoic acid, the first antioxidant, and the heat stabilizer is 5:90-98:0.4-1:0.4-1.1.

[0051] In one alternative embodiment, the phenylsilane includes at least one of phenyltrimethoxysilane (PTMS), phenyltriethoxysilane (PTES), and diphenyldimethoxysilane (DPDMS).

[0052] In an optional embodiment, the first antioxidant comprises at least one selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098), and tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168). This achieves excellent high-temperature resistance in the material.

[0053] In one optional embodiment, the heat stabilizer comprises cuprous iodide (CuI) and potassium iodide (KI); the mass ratio of cuprous iodide to potassium iodide is 1:5-15. CuI forms a stable complex with the nitrogen atom of the amide group (-CO-NH-) in the PA12 molecular chain, effectively preventing the nitrogen-hydrogen bond (NH) from dehydrogenating upon heating and avoiding yellowing; it also prevents the lactam from dehydrating to form an imine structure, inhibiting polymer chain breakage; KI acts as a synergist for copper salts, enhancing the stabilizing effect of cuprous iodide. The heat stabilizer can capture thermal oxygen free radicals, inhibiting the thermal degradation of SEBS and polyphenylene ether (PPO) during high-temperature processing and long-term use, thereby reducing the molecular weight decrease, discoloration, brittleness, and mechanical degradation of cable insulation materials during long-term thermal aging, and improving the high-temperature resistance of cable insulation materials.

[0054] In an optional embodiment, step (2) further includes adding a first lubricant; optionally, the first lubricant includes at least one of ethylene bis-stearamide, pentaerythritol stearate, glyceryl monostearate, and polyethylene wax; the mass ratio of the modified boron nitride to the first lubricant is 5:0.2-0.5.

[0055] In one optional embodiment, the hydroxylation treatment of boron nitride includes the following steps: sintering boron nitride powder in a corundum crucible under a static air atmosphere, followed by cooling to obtain hydroxylated boron nitride. Optionally, the thickness of the boron nitride powder is 0.7 cm-0.9 cm, the sintering temperature is 500℃-600℃, the sintering time is 1 h-2 h, and the heating rate is 3℃ / min-7℃ / min. Simultaneously, the prepared hydroxylated boron nitride is sealed and stored to prevent moisture absorption. Hydroxylation treatment of boron nitride can improve its dispersibility and interfacial compatibility.

[0056] In one optional embodiment, the unmodified polydodecanoic acid has a long-term maximum service temperature of 90°C, a water absorption rate of 1.5%, a dielectric strength of 28kV / mm-32kV / mm in a dry state, and a tensile strength of 35MPa-50MPa. The modified polydodecanoic acid has a long-term maximum service temperature of 120°C, a water absorption rate of 0.5%, a dielectric strength of 30kV / mm-45kV / mm in both dry and humid states, stable electrical properties at high temperatures, and stable volume resistivity and dielectric strength; its tensile strength is 50MPa-60MPa.

[0057] In one optional embodiment, the reaction temperature is 60°C-80°C and the time is 2.5h-3.5h.

[0058] In one optional embodiment, the mixing temperature is 30°C-40°C and the time is 8 min-15 min.

[0059] In one optional embodiment, in the first extrusion granulation step, the feeding frequency is 20Hz-35Hz, the extrusion temperature is successively 160℃-180℃, 200℃-215℃, 215-225℃, 225-235℃, and 220℃-230℃, and the die head temperature is 220℃-230℃.

[0060] In a second aspect, the present invention provides a modified polydodecanoic acid, prepared by the preparation method described in the first aspect.

[0061] Thirdly, the present invention provides the application of modified polydodecanoic acid prepared by the preparation method described in the first aspect or the modified polydodecanoic acid described in the second aspect in cable insulation materials.

[0062] Fourthly, the present invention provides a cable insulation material, comprising, by weight, the raw materials of the cable insulation material comprising: 34-50 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer, 5-30 parts of polyphenylene ether, 5-20 parts of modified polydodecyl lactam, 5-10 parts of compatibilizer, 5-30 parts of filler oil, 3-6 parts of flow modifier, 0.5-1 part of second antioxidant, and 0.3-0.8 parts of second lubricant; The modified polydodecanoic acid is the modified polydodecanoic acid prepared by the preparation method described in the first aspect or the modified polydodecanoic acid described in the second aspect.

[0063] It should be noted that modified polydodecyl lactam and polyphenylene ether exhibit good compatibility, improving the strength and dielectric properties of the SEBS / PPO system, addressing issues of high-temperature deformation and large creep, and providing high-strength structural support at high temperatures. During thermal aging, the heat stabilizer synergistically inhibits the thermal degradation of SEBS and PPO during high-temperature processing and long-term use, thereby reducing issues such as molecular weight decrease, dielectric property degradation, discoloration, brittleness, and mechanical attenuation during long-term thermal aging, and comprehensively improving the overall performance of the insulating material.

[0064] In this invention, SEBS serves as the continuous phase, ensuring the insulating material exhibits the flexible feel of a thermoplastic elastomer. SEBS has a hydrogenated structure with saturated double bonds, providing resistance to oxygen, ozone, and UV radiation. Combined with the heat stabilizer in modified polydodecanoic acid, it forms a dual weather-resistant system, significantly extending its outdoor service life. Simultaneously, SEBS, as the matrix soft segment, forms an island structure with the modified polydodecanoic acid and PPO hard segments, balancing rigidity, high-temperature resistance, elasticity, and toughness. This achieves a balance where the hard segments provide strength and heat resistance, while the soft segments provide flexibility and toughness, giving the material both the high-temperature resistance of engineering plastics and the properties of an elastomer.

[0065] It should be noted that polyphenylene ether (PPE) has a glass transition temperature as high as 210℃, and is completely compatible with the PS block in SEBS, forming a new phase region with an even higher glass transition temperature. This is equivalent to implanting a high-temperature resistant skeleton into the soft SEBS matrix, significantly improving the material's resistance to creep and compression set above 125℃. Simultaneously, PPE is inherently flame-retardant, creating conditions for "burden reduction": PPE has a limiting oxygen index of approximately 29%, making it a UL94 V-2 grade material; moreover, PPE contains a rigid benzene ring structure with strong heat resistance, directly transforming into a carbonaceous skeleton upon heating. During combustion, it forms a dense, expanded char layer, isolating oxygen and heat, preventing further combustion. Therefore, the amount of added halogen-free flame retardant can be controlled to below 25% or even lower (compared to 50%-60% for conventional halogen-free flame-retardant polyolefins), thus significantly preserving the mechanical properties of the insulating material.

[0066] In one alternative embodiment, the structure of the hydrogenated styrene-ethylene-butene-styrene block copolymer includes at least one of linear and star-shaped structures.

[0067] In one alternative embodiment, in the hydrogenated styrene-ethylene-butene-styrene block copolymer, the mass fraction of styrene structural units is 30%-35%, and the mass fraction of ethylene-butene structural units is 65%-70%.

[0068] In one alternative embodiment, the hydrogenated styrene-ethylene-butene-styrene block copolymer has an elongation of 400%-800% and a Shore A hardness of 70-80.

[0069] In one optional embodiment, the polyphenylene ether has a molecular weight of 30,000 g / mol to 50,000 g / mol. The resulting cable insulation material exhibits good high-temperature resistance, good flame retardancy, self-extinguishing properties, good electrical insulation, and high dimensional stability. If the molecular weight is greater than 50,000 g / mol, the molecular chains are longer, the degree of entanglement is high, the melt viscosity is extremely high, the fluidity is poor, molding and processing are difficult, requiring higher temperatures and pressures, and extruded cables are prone to surface roughness and poor cable forming. If the molecular weight is less than 30,000 g / mol, the molecular chains are shorter, the melt viscosity is significantly reduced, the fluidity is good, but the mechanical strength and high-temperature resistance are significantly decreased.

[0070] In one alternative embodiment, the compatibilizer comprises at least one of an oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer and a non-oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer.

[0071] In one alternative embodiment, the filler oil includes at least one of naphthenic oil and paraffin oil.

[0072] In one alternative embodiment, the flow modifier comprises a silicone masterbatch supported on a polypropylene carrier.

[0073] In one alternative embodiment, the second lubricant comprises at least one of stearic acid, calcium stearate, magnesium stearate, and polyethylene wax.

[0074] In one alternative embodiment, the second antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076).

[0075] In an alternative implementation, a flame retardant is also included.

[0076] In one alternative embodiment, the flame retardant includes at least one of magnesium hydroxide, aluminum diethylphosphite (ADP), and an intumescent flame retardant.

[0077] It's important to note that the core of magnesium hydroxide is "physical cooling + barrier dilution." Its flame retardancy doesn't rely on chemical reactions to break the chain reaction; instead, it directly absorbs heat. This endothermic process is driven by the breaking of chemical bonds, not a physical phase change (like water evaporation). Therefore, its endothermic efficiency is far higher than that of ordinary fillers, and it is irreversible.

[0078] Aluminum diethylphosphite (ADP) exhibits a typical gas-phase / condensed-phase dual-mechanism synergy. When heated to 350-450°C, ADP volatilizes or sublimates, carrying ADP molecules to the flame zone. Near the flame's high temperature (>500°C), these molecules further decompose, generating phosphorus-containing free radicals (such as PO·). These free radicals capture high-energy free radicals (H·, OH·) in the combustion chain reaction, interrupting the chain reaction, much like spraying a chemical extinguishing agent into the flame. This significantly enhances the flame's self-extinguishing properties and reduces the peak heat release rate. ADP itself or its decomposition products promote cross-linking of the polymer matrix, forming an expanded char layer that physically isolates oxygen and heat, prevents dripping, and increases char residue.

[0079] In one optional embodiment, the intumescent flame retardant comprises, by weight, 25-35 parts of melamine polyphosphate (MPP), 5-15 parts of pentaerythritol, and 15-25 parts of aluminum magnesium hydrotalcite.

[0080] In intumescent flame retardants, MPP serves as both an acid and gas source, with a thermal decomposition temperature >280℃ and long-term heat resistance up to 180℃. Pentaerythritol and aluminum-magnesium hydrotalcite synergistically form a continuous, dense, and expandable stable barrier char layer upon heating, effectively improving the flame retardant properties of the composite material. When polyphenylene ether (PPE), modified polydodecyl lactam (PCL), and intumescent flame retardants are combined, MPP exhibits near-neutral properties, excellent compatibility, a dense structure, and low water absorption. It is non-corrosive and does not catalytically degrade PA12, SEBS, or PPE. Modified PCL enhances the flame retardancy of the intumescent flame retardant, while PPE acts as a char source, significantly improving flame retardant efficiency. This results in a comprehensive upgrade in the material's flame retardancy, temperature resistance, aging resistance, and hydrolysis resistance.

[0081] In one alternative embodiment, when the flame retardant is magnesium hydroxide, an anti-dripping agent is also included.

[0082] In one alternative embodiment, the anti-dripping agent comprises polytetrafluoroethylene.

[0083] In one optional embodiment, the anti-dripping agent is present in 2-4 parts by weight.

[0084] In one optional embodiment, the flame retardant is present in 10-35 parts by weight.

[0085] Fifthly, the present invention provides a method for preparing the cable insulation material described in the fourth aspect, comprising the following steps: mixing the raw materials of the cable insulation material and then sequentially performing a second extrusion granulation to obtain the cable insulation material.

[0086] It should be noted that the preparation method of cable insulation material includes the steps of first stirring and letting the hydrogenated styrene-ethylene-butene-styrene block copolymer and filler oil stand to ensure that SEBS fully absorbs oil and swells without dry powder; then mixing with the remaining raw materials and performing a second extrusion granulation.

[0087] Furthermore, the stirring temperature is 50℃-60℃, and the stirring time is 40min-50min.

[0088] Furthermore, the settling time is 2-3 hours.

[0089] Furthermore, the mixing temperature is 30℃-50℃, and the time is 10min-15min.

[0090] In one optional embodiment, in the second extrusion granulation step, the feeding frequency is 20Hz-35Hz, the extrusion temperature is successively 170℃-190℃, 210℃-220℃, 220℃-230℃, 230℃-240℃, 220℃-230℃, and the die head temperature is 220℃-230℃.

[0091] In this invention, the linear hydrogenated styrene-ethylene-butene-styrene block copolymer (SEBS) was purchased from Yueyang Petrochemical, model YH-503, with a block ratio of 33 / 67; the star-shaped hydrogenated styrene-ethylene-butene-styrene block copolymer (SEBS) was purchased from Yueyang Petrochemical, model YH-604, with a block ratio of 33 / 67; the polyphenylene ether was purchased from Asahi Kasei, model HP-750, with a molecular weight of 30,000-38,000 g / mol; the general-purpose polydodecyl lactam was purchased from EMS, model Grilamid L 25nature 6112; the cuprous iodide was purchased from William Blythe (UK), model i-blythe S5050; and the potassium iodide was purchased from William Blythe (UK), model i-blythe™. S5070; Hexagonal boron nitride was purchased from Suzhou Kangpeng Chemical Co., Ltd.; Hydroxysilicone oil was purchased from Anhui Bithai Materials Co., Ltd., model BTH-6; Phenylacetyltrimethoxysilane was purchased from Jiangxi Hongbai New Materials Co., Ltd., model HP-P913; Phenylacetyltriethoxysilane was purchased from Hubei Jusheng Technology Co., Ltd., model HD-128; Diphenyldimethoxysilane was purchased from Jiangxi Hongbai New Materials Co., Ltd., model HP-6202; Oil-extended maleic anhydride grafted hydrogenated styrene-ethylene The following products were purchased: ethylene-butene-styrene block copolymer (GPM5618) from Ningbo Nengzhiguang; non-oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer (GPM5601) from Ningbo Nengzhiguang; paraffin oil (KP600) from PetroChina; ethylene bis-stearamide (WAX2001) from Kesai Chenggong; and pentaerythritol stearate (LOXIOL@P) from Emery, Germany. 861 / 3.5; Polyethylene wax was purchased from Honeywell, model AC 316A; Silicone masterbatch for polypropylene carrier was purchased from Chengdu Silike Technology Co., Ltd., model LYSI-306C, with a content of 50wt%; Stearic acid was purchased from Indonesia Chunjin, model 1865; Calcium stearate was purchased from Jiangsu Puleisi Biotechnology Co., Ltd., with a molecular weight of 607.02 g / mol; Magnesium hydroxide was purchased from Omya, model Magnum S. 12E; Aluminum diethyl phosphite (ADP) was purchased from Clariant, model OP1230; Intumescent flame retardant was purchased from Adico, model FP-2500S; Polytetrafluoroethylene powder was purchased from Daikin, model FA-500H; Antioxidant 1098 was purchased from Tianjin Lianlong New Material Co., Ltd.; Antioxidant 1076 was purchased from Tianjin Lianlong New Material Co., Ltd.; Antioxidant 1010 was purchased from Tianjin Lianlong New Material Co., Ltd.; Antioxidant 168 was purchased from Tianjin Lianlong New Material Co., Ltd.

[0092] Example 1 This embodiment provides a method for preparing modified polydodecanoic acid, comprising the following steps: (1) Take 100 parts of boron nitride powder and place it in a corundum crucible. The thickness of the powder is controlled at 0.8 cm. Under air atmosphere, the temperature is raised to 550°C at a heating rate of 5°C / min and kept at the temperature for 1.5 h for hydroxyl activation treatment. Then, it is naturally cooled to room temperature to obtain hydroxylated boron nitride. (2) Add 500 parts of anhydrous toluene to a three-necked flask, purge with nitrogen for 30 minutes to completely remove oxygen and moisture from the system; then add 100 parts of hydroxylated boron nitride, turn on ultrasonic dispersion for 30 minutes to form a stable suspension; (3) Under nitrogen protection, 1 part of phenyltrimethoxysilane and 0.8 parts of hydroxyl silicone oil were added dropwise to the above suspension. After the addition was completed, the temperature was raised to 70°C and stirred for 3 hours to allow the phenyltrimethoxysilane to graft onto the hydroxyl groups on the surface of OH-BN. At the same time, the phenyltrimethoxysilane partially capped the active hydroxyl groups of the hydroxyl silicone oil. After the reaction was completed, the mixture was filtered while hot and the filter cake was washed 2-3 times with anhydrous ethanol to remove unreacted phenyltrimethoxysilane, hydroxyl silicone oil and reaction byproducts. The mixture was then dried under vacuum at 110°C for 6 hours, cooled to room temperature, ground and passed through a 100-mesh sieve to obtain modified boron nitride. (4) 93.7 parts of PA12 particles, 5 parts of modified boron nitride, 0.3 parts of lubricant ethylene bis-stearamide, 0.2 parts of antioxidant 1098, 0.2 parts of antioxidant 168 and 0.6 parts of heat stabilizer (including CuI and KI with a mass ratio of 1:10) were mixed at 40°C for 15 min; then the mixture was extruded and granulated in a twin-screw extruder. The processing conditions from the feed port to the die head were as follows: feed frequency 30 Hz, processing temperature 170°C in zone 1, 200°C in zone 2, 220°C in zone 3, 225°C in zone 4, 225°C in zone 5, 235°C in zone 6, 235°C in zone 7, 235°C in zone 8, 230°C in zone 9, and die head temperature 230°C to obtain modified polydodecyl lactam.

[0093] Example 2 This embodiment provides a method for preparing modified polydodecanoic acid, comprising the following steps: (1) Take 100 parts of boron nitride powder and place it in a corundum crucible. The thickness of the powder is controlled at 0.7 cm. Under air atmosphere, the temperature is raised to 500℃ at a heating rate of 3℃ / min and kept at the temperature for 2 hours to carry out hydroxyl activation treatment. Then, it is naturally cooled to room temperature to obtain hydroxylated boron nitride. (2) Add 500 parts of anhydrous toluene to a three-necked flask, purge with nitrogen for 30 minutes to completely remove oxygen and moisture from the system; then add 100 parts of hydroxylated boron nitride, turn on ultrasonic dispersion for 30 minutes to form a stable suspension; (3) Under nitrogen protection, 0.8 parts of phenyltriethoxysilane and 0.5 parts of hydroxyl silicone oil were slowly added dropwise to the above suspension. After the addition was completed, the temperature was raised to 60°C and stirred for 3.5 h to allow the phenyltriethoxysilane to undergo a grafting reaction with the hydroxyl groups on the surface of OH-BN. At the same time, the phenyltriethoxysilane partially capped the active hydroxyl groups of the hydroxyl silicone oil. After the reaction was completed, the mixture was filtered while hot and the filter cake was washed 2-3 times with anhydrous ethanol to remove unreacted phenyltriethoxysilane, hydroxyl silicone oil and reaction byproducts. The mixture was then vacuum dried at 110°C for 6 h, cooled to room temperature, ground and passed through a 100-mesh sieve to obtain modified boron nitride. (4) Mix 90 parts of PA12 granules, 5 parts of modified boron nitride, 0.5 parts of lubricant pentaerythritol stearate, 0.5 parts of antioxidant 1076, 0.5 parts of antioxidant 168 and 0.4 parts of heat stabilizer (including CuI and KI in a mass ratio of 1:5) at 35°C for 11 min; then extrude and granulate the mixture into a twin-screw extruder. The processing conditions from the feed port to the die head are as follows: feed frequency 20 Hz, processing temperature 160°C in zone 1, 210°C in zone 2, 215°C in zone 3, 230°C in zone 4, 230°C in zone 5, 230°C in zone 6, 230°C in zone 7, 230°C in zone 8, 225°C in zone 9, and die head temperature 225°C to obtain modified polydodecyl lactam.

[0094] Example 3 This embodiment provides a method for preparing modified polydodecanoic acid, comprising the following steps: (1) Take 100 parts of boron nitride powder and place it in a corundum crucible. The thickness of the powder is controlled at 0.9 cm. Under air atmosphere, the temperature is raised to 600℃ at a heating rate of 7℃ / min and kept at the temperature for 1 h for hydroxyl activation treatment. The powder is then naturally cooled to room temperature to obtain hydroxylated boron nitride. (2) Add 500 parts of anhydrous toluene to a three-necked flask, purge with nitrogen for 30 minutes to completely remove oxygen and moisture from the system; then add 100 parts of hydroxylated boron nitride, turn on ultrasonic dispersion for 30 minutes to form a stable suspension; (3) Under nitrogen protection, 0.5 parts of diphenyldimethoxysilane and 1 part of hydroxyl silicone oil were slowly added dropwise to the above suspension. After the addition was completed, the temperature was raised to 80°C and stirred for 2.5 h to allow the diphenyldimethoxysilane to undergo a grafting reaction with the hydroxyl groups on the surface of OH-BN. At the same time, the diphenyldimethoxysilane partially capped the active hydroxyl groups of the hydroxyl silicone oil. After the reaction was completed, the filter cake was filtered while hot and washed with anhydrous ethanol 2-3 times to remove unreacted diphenyldimethoxysilane, hydroxyl silicone oil and reaction byproducts. The filter cake was dried under vacuum at 110°C for 6 h, cooled to room temperature and ground, and passed through a 100-mesh sieve to obtain modified boron nitride. (4) Mix 98 parts of PA12 granules, 5 parts of modified boron nitride, 0.2 parts of lubricant polyethylene wax, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168 and 1.1 parts of heat stabilizer (including CuI and KI with a mass ratio of 1:15) at 30°C for 8 minutes; then extrude and granulate the mixture into a twin-screw extruder. The processing conditions from the feed port to the die head are as follows: feed frequency 35Hz, processing temperature 180°C in zone 1, 215°C in zone 2, 225°C in zone 3, 235°C in zone 4, 235°C in zone 5, 225°C in zone 6, 225°C in zone 7, 225°C in zone 8, 220°C in zone 9, and die head temperature 220°C to obtain modified polydodecyl lactam.

[0095] Example 4 This embodiment provides a method for preparing cable insulation material, including the following steps: (1) 100 parts of SEBS YH-503 (linear structure, 33% mass fraction of styrene structural unit, 67% mass fraction of ethylene-butene structural unit, elongation of 480%, Shore A hardness of 74) and 40 parts of paraffin oil were put into a high-speed mixer and mixed at 55°C for 45 min. Then the mixture was allowed to stand for 2 h to obtain the mixture. (2) 68 parts of the mixture, 15 parts of polyphenylene ether HP-750, 5 parts of modified polydodecyl lactam prepared in Example 1, 8 parts of oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer, 0.25 parts of antioxidant 1010, 0.25 parts of antioxidant 168, 3 parts of silicone masterbatch of polypropylene carrier, and 0.5 parts of calcium stearate were added to a mixer in sequence and mixed at 45°C for 15 min. (3) The mixture is fed into a twin-screw extruder for extrusion granulation. The processing conditions from the feed port to the die head are as follows: feeding frequency 30Hz, processing temperature 180℃ in zone 1, 215℃ in zone 2, 225℃ in zone 3, 235℃ in zone 4, 235℃ in zone 5, 235℃ in zone 6, 235℃ in zone 7, 225℃ in zone 8, 225℃ in zone 9, and die head temperature 230℃. (4) After drying the extruded granules, press them into sheets using a flat vulcanizing agent at 200°C to obtain cable insulation material.

[0096] Example 5 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 4, except that the mixture contains 53 parts of raw materials and 30 parts of polyphenylene ether.

[0097] Example 6 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 4, except that the mixture is 58 parts and the modified polydodecyl lactam is 15 parts.

[0098] Example 7 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 4, except that the mixture is 53 parts and the modified polydodecanoic acid is 20 parts.

[0099] Example 8 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 4, except that the mixture contains 58 parts, modified polydodecyl lactam contains 15 parts, calcium stearate contains 0.8 parts, and also includes 2.5 parts of anti-dripping agent polytetrafluoroethylene and 35 parts of magnesium hydroxide.

[0100] Example 9 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 8, except that 35 parts of magnesium hydroxide are replaced with 25 parts of intumescent flame retardant, and the addition of polytetrafluoroethylene is omitted; wherein, the intumescent flame retardant includes: 30 parts of MPP (melamine polyphosphate), 10 parts of pentaerythritol, and 20 parts of aluminum magnesium hydrotalcite.

[0101] Example 10 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 8, except that the mixture is 50 parts, 35 parts of magnesium hydroxide is replaced with 20 parts of diethyl aluminum hypophosphite, and the addition of polytetrafluoroethylene is omitted.

[0102] Example 11 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 4, except that the modified polydodecanoic acid prepared in Embodiment 1 is replaced with the modified polydodecanoic acid prepared in Embodiment 2.

[0103] Example 12 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Example 4, except that the modified polydodecanoic acid prepared in Example 1 is replaced with the modified polydodecanoic acid prepared in Example 3.

[0104] Example 13 This embodiment provides a method for preparing cable insulation material, including the following steps: (1) Add 100 parts of SEBS YH-503 and 70 parts of naphthenic oil to a high-speed mixer, mix at 50°C for 50 min, and then let stand for 3 h to obtain a mixture. (2) 58 parts of the mixture, 5 parts of polyphenylene ether HP-750, 10 parts of modified polydodecanoic acid prepared in Example 1, 10 parts of non-oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer, 0.25 parts of antioxidant 1010, 0.25 parts of antioxidant 168, 6 parts of silicone masterbatch of polypropylene carrier, and 0.3 parts of stearic acid were added to a mixer in sequence and mixed at 30°C for 10 min. (3) The mixture enters the twin-screw extruder for extrusion granulation. The processing conditions from the feed port to the die head are as follows: feeding frequency 25Hz, processing temperature 190℃ in zone 1, 220℃ in zone 2, 220℃ in zone 3, 230℃ in zone 4, 240℃ in zone 5, 240℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, 220℃ in zone 9, and die head temperature 220℃. (4) After drying the extruded granules, press them into sheets using a flat vulcanizing agent at 200°C to obtain cable insulation material.

[0105] Example 14 This embodiment provides a method for preparing cable insulation material, including the following steps: (1) 100 parts of SEBS YH-503 and 40 parts of naphthenic oil were put into a high-speed mixer and mixed at 60°C for 40 min. Then the mixture was allowed to stand for 2.5 h to obtain the mixture. (2) 58 parts of the mixture, 15 parts of polyphenylene ether HP-750, 5 parts of modified polydodecyl lactam prepared in Example 1, 5 parts of non-oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer, 1 part of antioxidant 1076, 5 parts of silicone masterbatch of polypropylene carrier, and 0.4 parts of polyethylene wax were added to the mixer in sequence and mixed at 50°C for 12 min. (3) The mixture is fed into the twin-screw extruder for extrusion granulation. The processing conditions from the feed port to the die head are as follows: feeding frequency 35Hz, processing temperature 170℃ in zone 1, 210℃ in zone 2, 230℃ in zone 3, 240℃ in zone 4, 230℃ in zone 5, 230℃ in zone 6, 230℃ in zone 7, 220℃ in zone 8, 230℃ in zone 9, and die head temperature 225℃. (4) After drying the extruded granules, press them into sheets using a flat vulcanizing agent at 200°C to obtain cable insulation material.

[0106] Example 15 This embodiment provides a method for preparing cable insulation material, which is basically the same as the steps in Embodiment 9, except that the SEBS type is YH-604 (star structure, styrene structural unit mass fraction of 33%, ethylene-butene structural unit mass fraction of 67%, elongation of 530%, Shore A hardness of 76).

[0107] Comparative Example 1 This comparative example provides a method for preparing modified polydodecanoic acid, which is basically the same as the steps in Example 1, except that the addition of boron nitride is omitted, that is, the modified boron nitride in steps (1)-(3) and step (4) is omitted, and the weight of PA12 particles in step (4) is modified to 98.7 parts.

[0108] Comparative Example 2 This comparative example provides a method for preparing modified polydodecanoic acid, which is basically the same as the steps in Example 1, except that steps (1) to (3) are omitted, and the modified boron nitride in step (4) is replaced with the same weight of boron nitride.

[0109] Comparative Example 3 This comparative example provides a method for preparing cable insulation material, which is basically the same as the steps in Example 4, except that the modified polydodecanoic acid prepared in Example 1 is replaced with the modified polydodecanoic acid prepared in Comparative Example 1.

[0110] Comparative Example 4 This comparative example provides a method for preparing cable insulation material, which is basically the same as the steps in Example 4, except that the modified polydodecanoic acid prepared in Example 1 is replaced with the modified polydodecanoic acid prepared in Comparative Example 2.

[0111] Comparative Example 5 This comparative example provides a method for preparing cable insulation material, which is basically the same as the steps in Example 4, except that the modified polydodecyl lactam is replaced with the same weight of polyphenylene ether, that is, 20 parts of polyphenylene ether.

[0112] Comparative Example 6 This comparative example provides a method for preparing cable insulation material, which is basically the same as the steps in Example 4, except that polyphenylene ether is replaced with the same weight parts of modified polydodecanoic acid, that is, the modified polydodecanoic acid is 20 parts.

[0113] Comparative Example 7 This comparative example provides a method for preparing cable insulation material, which is basically the same as the steps in Example 4, except that the modified polydodecanoic acid is replaced with the same weight of unmodified polydodecanoic acid.

[0114] Experimental Example 1 The modified polydodecanoic acid prepared in Examples 1-3 and Comparative Examples 1-2 were tested for tensile strength, elongation at break, dielectric strength, and volume resistivity before aging at 20°C. After aging at 150°C for 10 days, the tensile strength, elongation at break, dielectric strength, and volume resistivity were tested again. The tensile strength retention rate and elongation at break retention rate were calculated. Simultaneously, two commercially available PA12 products were used as control groups. Control group 1 was purchased from EMS Switzerland, model GRILAMID L 25H; control group 2 was purchased from EMS Switzerland, model GRILAMID L 25 W 20 X. The results are shown in Table 1. Tensile strength: Refer to the test method in GB / T 528-2009; Elongation at break: Refer to the test method in GB / T 528-2009; Dielectric strength: Refer to the test method in GB / T 1408.1-2016; Volume resistivity: Refer to the test method in GB / T 31838.2-2019; Tensile strength retention rate (%) = Tensile strength after aging / Tensile strength before aging; Elongation at break retention rate (%) = Elongation at break after aging / Elongation at break before aging.

[0115] Table 1. Test results of modified polydodecanoic acid and polydodecanoic acid in each example and comparative example.

[0116] As can be seen from Table 1, compared with control groups 1-2 and comparative examples 1-2, the modified polydodecanoic acid prepared in Examples 1-3 of the present invention has improved dielectric strength and volume resistivity. At the same time, the dielectric strength and volume resistivity after aging are maintained at a high level, and the retention rate of tensile strength and elongation at break after aging are both higher than 70%.

[0117] Experiment Example 2 The cable insulation materials prepared in Examples 4-7, Examples 11-15, and Comparative Examples 3-7 were tested for tensile strength, elongation at break, dielectric strength, volume resistivity, and vertical burning performance (for flame retardancy rating) at room temperature. After aging at 175°C for 10 days, tensile strength, elongation at break, dielectric strength, and volume resistivity were also tested, and the tensile strength retention rate and elongation at break retention rate were calculated. Meanwhile, commercially available TPE non-flame retardant cable materials were used as control groups. Control group 3 was purchased from Shandong Dawn Polymer Materials Co., Ltd., model TPE DL1-90AMS; control group 4 was purchased from Guangdong Antuopu Polymer Technology Co., Ltd., model TPE 2585F-ESS-1284S. The test results are shown in Table 2.

[0118] Table 2. Test results of cable insulation material performance for each embodiment, comparative example, and control group.

[0119] Table 2 shows that the cable insulation material prepared by this invention exhibits excellent tensile properties, dielectric properties, and high-temperature resistance. Comparative Example 3, with the addition of modified PA12 but without modified BN, showed no improvement in dielectric strength or high-temperature resistance. Comparative Example 4, with the addition of modified PA12 but without modified BN, lacked a cross-linked coating network, resulting in no improvement in high-temperature resistance. Comparative Example 5, with its high polyphenylene ether content, resulted in excessive rigid PPO that could not be dispersed within the SEBS matrix, leading to mediocre dielectric properties in the cable insulation material, which significantly decreased after thermal aging. Comparative Example 6 shows that while the increased content of modified PA12 without polyphenylene ether improved the room-temperature dielectric strength of the cable insulation, it resulted in poor high-temperature resistance. Comparative Example 7 shows that the addition of unmodified PA12 only improved the dielectric properties at room temperature, without improving high-temperature resistance.

[0120] Experimental Example 3 The cable insulation materials prepared in Examples 8-10 were subjected to vertical combustion performance (flame retardancy rating assessment), tensile strength, elongation at break, dielectric strength, and volume resistivity tests; and after aging at 175℃ for 10 days, tensile strength, elongation at break, dielectric strength, and volume resistivity tests were also conducted, and the tensile strength retention rate and elongation at break retention rate were calculated. Meanwhile, commercially available TPE flame-retardant cable materials were used as control groups; control group 5 was purchased from Shandong Dawn Polymer Materials Co., Ltd., model TPE DLWZ1-85AVW E(EN); control group 6 was purchased from Guangdong Antop Polymer Technology Co., Ltd., model TPE 2285B-ESS-2051S. The test results are shown in Table 4. Vertical flammability: Refer to the test method of GB / T 2408-2021. t1 is the total time (in seconds) from the moment the torch is removed after the first 10s±0.5s flame is applied to the sample until the flame on the cable insulation material is completely extinguished. t2 is the time (in seconds) from the moment the torch is removed after t1 is completely extinguished, after the second 10s±0.5s flame is applied to the sample until the flame on the sample is completely extinguished. t3 is the time (in seconds) after t2 (the second afterglow) is completely extinguished, without resetting the timer, until the flameless glow (afterglow) on the sample completely disappears. The flame retardant rating criteria are shown in Table 3, and the test results are shown in Table 4.

[0121] Table 3 Flame Retardant Rating

[0122] Table 4. Test results of cable insulation material performance for each embodiment, comparative example, and control group.

[0123] As shown in Table 4, among the different flame retardant combinations in Examples 8-10, the formulation combination in Example 10 exhibits the best material performance, maintaining excellent overall performance even after thermal aging. Compared to the control group, the cable insulation material prepared in these examples demonstrates superior dielectric strength, volume resistivity before aging, and better tensile strength, elongation at break retention, and volume resistivity after aging. Combined with its advantages in processability, chemical resistance, and abrasion resistance, it has broad applications in the field of high-temperature cables.

[0124] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing modified polydodecanoic acid, characterized in that, Includes the following steps: (1) Hydroxylated boron nitride, phenylsilane and hydroxyl silicone oil are reacted to obtain modified boron nitride; (2) The modified boron nitride, polydodecanoic acid, first antioxidant and heat stabilizer are mixed and then subjected to first extrusion granulation to obtain the modified polydodecanoic acid.

2. The method for preparing modified polydodecanoic acid according to claim 1, characterized in that, The mass ratio of the hydroxylated boron nitride, the phenylsilane, and the hydroxyl silicone oil is 100:0.5-1:0.5-1; And / or, the mass ratio of the modified boron nitride, the polydodecyl lactam, the first antioxidant, and the heat stabilizer is 5:90-98:0.4-1:0.4-1.

1.

3. The method for preparing modified polydodecanoic acid according to claim 1 or 2, characterized in that, The phenylsilane includes at least one of phenyltrimethoxysilane, phenyltriethoxysilane, and diphenyldimethoxysilane; And / or, the first antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and tris[2,4-di-tert-butylphenyl]phosphite; And / or, the heat stabilizer comprises cuprous iodide and potassium iodide; optionally, the mass ratio of cuprous iodide to potassium iodide is 1:5-15; And / or, in step (2), a first lubricant is added; optionally, the first lubricant includes at least one of ethylene bis-stearamide, pentaerythritol stearate, glyceryl monostearate, and polyethylene wax; the mass ratio of the modified boron nitride to the first lubricant is 5:0.2-0.

5.

4. The method for preparing modified polydodecanoic acid according to claim 1, characterized in that, The method for preparing the hydroxylated boron nitride includes: sintering boron nitride to obtain it; Optionally, the sintering temperature is 500℃-600℃ and the time is 1h-2h; And / or, the reaction is carried out at a temperature of 60°C-80°C for a time of 2.5h-3.5h; And / or, the mixing temperature is 30℃-40℃, and the time is 8min-15min; And / or, in the first extrusion granulation step, the feeding frequency is 20Hz-35Hz, the extrusion temperature is 160℃-180℃, 200℃-215℃, 215-225℃, 225-235℃, 220℃-230℃, and the die head temperature is 220℃-230℃.

5. A modified polydodecanoic acid, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.

6. The application of the modified polydodecanoic acid prepared by the preparation method according to any one of claims 1-4 or the modified polydodecanoic acid according to claim 5 in cable insulation materials.

7. A cable insulation material, characterized in that, include: By weight, the raw materials of the cable insulation material include: 34-50 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer, 5-30 parts of polyphenylene ether, 5-20 parts of modified polydodecyl lactam, 5-10 parts of compatibilizer, 5-30 parts of filler oil, 3-6 parts of flow modifier, 0.5-1 part of second antioxidant, and 0.3-0.8 parts of second lubricant; The modified polydodecanoic acid is the modified polydodecanoic acid prepared by the preparation method according to any one of claims 1-4 or the modified polydodecanoic acid according to claim 5.

8. The cable insulation material according to claim 7, characterized in that, The structure of the hydrogenated styrene-ethylene-butene-styrene block copolymer includes at least one of linear and star-shaped structures; And / or, in the hydrogenated styrene-ethylene-butene-styrene block copolymer, the mass fraction of styrene structural units is 30%-35%, and the mass fraction of ethylene-butene structural units is 65%-70%; And / or, the elongation of the hydrogenated styrene-ethylene-butene-styrene block copolymer is 400%-800%, and the Shore A hardness is 70-80; And / or, the molecular weight of the polyphenylene ether is 30,000 g / mol to 50,000 g / mol; And / or, the compatibilizer includes at least one of oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer and non-oil-extended maleic anhydride-grafted hydrogenated styrene-ethylene-butene-styrene block copolymer. And / or, the filler oil includes at least one of naphthenic oil and paraffin oil; And / or, the flow modifier comprises silicone masterbatch with a polypropylene carrier; And / or, the second lubricant comprises at least one of stearic acid, calcium stearate, magnesium stearate, and polyethylene wax; And / or, the second antioxidant comprises at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl]phosphite, and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; And / or, may also include the addition of flame retardants; Optionally, the flame retardant includes at least one of magnesium hydroxide, aluminum diethylphosphite, and intumescent flame retardant; Optionally, by weight, the intumescent flame retardant comprises: 25-35 parts of melamine polyphosphate, 5-15 parts of pentaerythritol, and 15-25 parts of aluminum magnesium hydrotalcite. Optionally, when the flame retardant is magnesium hydroxide, an anti-dripping agent may also be included; Optionally, the anti-dripping agent comprises polytetrafluoroethylene; Optionally, the anti-dripping agent is present in 2-4 parts by weight; Optionally, the flame retardant is 10-35 parts by weight.

9. A method for preparing the cable insulation material according to claim 7 or 8, characterized in that, Includes the following steps: The raw materials for the cable insulation material are mixed and then subjected to a second extrusion granulation process to obtain the cable insulation material.

10. The method for preparing cable insulation material according to claim 9, characterized in that, In the second extrusion granulation step, the feeding frequency is 20Hz-35Hz, the extrusion temperature is 170℃-190℃, 210℃-220℃, 220℃-230℃, 230℃-240℃, 220℃-230℃, and the die head temperature is 220℃-230℃.

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