Halogen-free flame-retardant cable material composition as well as preparation method and application thereof

Abstract

The invention provides a halogen-free flame-retardant cable material composition as well as a preparation method and application thereof. The halogen-free flame-retardant cable material composition is prepared from the following components in parts by weight: 10 to 15 parts of resin matrix, 15 to 35 parts of compatilizer, 45 to 65 parts of flame retardant, 1 to 5 parts of charring agent, 0.05 to 0.5 part of silane coupling agent, 0.1 to 3 parts of carbon black master batch, 0.1 to 2 parts of silicone master batch and 0.1 to 1 part of antioxidant, the charring agent is modified montmorillonoid, and a modifier used by the montmorillonoid is a biomass intercalator. On the basis of a green halogen-free flame-retardant technology, by optimizing components of the cable material, improving a charring agent treatment mode and enhancing the internal synergistic effect of the material, the purpose of improving the flame-retardant performance and the charring effect of the cable material is achieved.

Description

Technical Field

[0001] This invention relates to the field of cable material technology, and more specifically, to a halogen-free flame-retardant cable material composition, its preparation method, and its application. Background Technology

[0002] Cables, as carriers of electricity and information transmission, play a vital role in modern industry, commerce, homes, and public facilities. With the acceleration of global industrialization and the ever-increasing demand for electricity, the cable industry has experienced rapid development. However, the fire risks that cables may face during use, especially the smoke and toxic gases produced during combustion, have become a major challenge to public safety and environmental protection. Therefore, developing cable materials with excellent flame-retardant properties and low smoke and non-toxicity during combustion has become an urgent need in the industry.

[0003] Currently, polyolefins are one of the commonly used cable materials. They possess excellent electrical and mechanical properties and are used as the main material for cable insulation layers and the base material for insulation sheaths. Their application has opened up and expanded the broad prospects for cable base materials. However, polyolefin polymers also have significant drawbacks, namely poor flame retardancy. They are flammable materials, and when used in wires and cables, they easily reach their ignition point under high voltage or overheating conditions, causing fires. Furthermore, the flames can spread rapidly along the wires throughout the entire circuit, causing the fire to expand instantly and resulting in incalculable losses to people and property.

[0004] To improve the flame retardant properties of polyolefin cable materials, halogenated flame retardants were initially proposed as flame-retardant materials for polyolefins. Due to their low addition amount and significant flame-retardant effect, halogenated flame retardants have long held an unshakeable position in the flame retardant field. However, with the expansion of their application, it has been discovered that the hydrogen halide gas generated by the combustion of halogenated flame retardants is highly destructive to the environment and also produces many carcinogens that cause significant harm to human health. While the addition of low-smoke halogen-free flame retardants reduces the generation of smoke and toxic gases, it often leads to a decrease in the flame retardant performance of the cable material. Especially under high-temperature conditions, the decomposition and escape of the flame retardant reduce the material's flame-retardant effect. Simultaneously, the char layer formed during combustion is incomplete, has low mechanical strength, and cannot effectively prevent the transfer of oxygen and heat, further reducing flame retardant performance. In conclusion, although low-smoke halogen-free flame-retardant cable materials have made significant progress in reducing the hazards of fires, there is still room for improvement in terms of flame retardant performance, overall material properties, processing compatibility, and environmental health.

[0005] Therefore, how to provide a low-smoke, halogen-free, flame-retardant, green and environmentally friendly cable material that can combine good mechanical properties, bending resistance, excellent charring properties and flame retardant properties is one of the important technical problems that need to be solved in the current cable material field. Summary of the Invention

[0006] The main objective of this invention is to provide a halogen-free flame-retardant cable material composition, its preparation method, and its application, so as to solve the problem that existing cable materials are difficult to simultaneously possess good mechanical properties, bending resistance, thermal stability, and flame-retardant properties.

[0007] To achieve the above objectives, a first aspect of the present invention provides a halogen-free flame-retardant cable material composition, comprising, by weight: 10 to 15 parts of a resin matrix, 15 to 35 parts of a compatibilizer, 45 to 65 parts of a flame retardant, 1 to 5 parts of a charring agent, 0.05 to 0.5 parts of a silane coupling agent, 0.1 to 3 parts of carbon black masterbatch, 0.1 to 2 parts of a silicone masterbatch, and 0.1 to 1 part of an antioxidant; the charring agent is modified montmorillonite, and the modifier used for the montmorillonite is a biomass intercalating agent.

[0008] Furthermore, the biomass intercalating agent is one or more of bio-based amphiphilic molecules, and the molecular structure of the bio-based amphiphilic molecule includes a hydrophilic end and a hydrophobic end; preferably, the biomass intercalating agent is selected from one or more of plant-based lecithin, L-ascorbic acid palmitate, plant-based sphingosine, and plant-based saponins.

[0009] Further, the charring agent is prepared by the following steps: Step A1, montmorillonite and biomass intercalating agent are mixed at a weight ratio of (3~6):1 and dispersed to obtain a mixed product; preferably, the dispersion is carried out by ball milling at a speed of 500±50 rpm and the dispersion time is 4±1h; Step A2, the mixed product is calcined at a temperature of 260℃~310℃ for 1h~3h to obtain the charring agent.

[0010] Furthermore, the resin matrix is ​​polyethylene, and the polyethylene is metallocene linear low-density polyethylene and / or linear low-density polyethylene.

[0011] Further, the compatibilizer is selected from one or more of ethylene-vinyl acetate, polyolefin elastomer and maleic anhydride; preferably, the compatibilizer is a compatibilizer composition formed by ethylene-vinyl acetate, polyolefin elastomer and maleic anhydride in a weight ratio of (12~18):(5~8):(1~2).

[0012] Furthermore, the flame retardant is selected from one or more of hydroxide-based flame retardants and / or phosphorus-based flame retardants; preferably, the hydroxide-based flame retardant includes magnesium hydroxide and aluminum hydroxide; and / or, the phosphorus-based flame retardant includes red phosphorus, microencapsulated red phosphorus, and phosphate esters.

[0013] Further, by weight, the halogen-free flame-retardant cable material composition comprises: 10 to 14 parts of resin matrix, 20 to 30 parts of compatibilizer, 50 to 60 parts of flame retardant, 1 to 5 parts of charring agent, 0.1 to 0.3 parts of silane coupling agent, 0.5 to 2 parts of carbon black masterbatch, 0.3 to 1.0 parts of silicone masterbatch, and 0.1 to 0.5 parts of antioxidant; preferably, by weight, the halogen-free flame-retardant cable material composition comprises: 11.5 13.5 parts of polyethylene, 14 to 20 parts of ethylene-vinyl acetate, 5 to 8 parts of polyolefin elastomer, 1 to 2 parts of maleic anhydride, 48 to 60 parts of magnesium hydroxide flame retardant, 1 to 3 parts of microencapsulated red phosphorus flame retardant, 2 to 5 parts of charring agent, 0.15 to 0.25 parts of silane coupling agent, 0.8 to 1.2 parts of carbon black masterbatch, 0.4 to 0.7 parts of silicone masterbatch, and 0.3 to 0.5 parts of antioxidant.

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned halogen-free flame-retardant cable material composition, comprising: step S1, mixing a resin matrix and a compatibilizer in a first mixing process to obtain a first material; step S2, adding a flame retardant to the first material and mixing it in a second mixing process to obtain a second material; step S3, adding a charring agent to the second material to obtain a third material; and step S4, extruding and granulating the third material sequentially to obtain the halogen-free flame-retardant cable material composition.

[0015] Further, in step S1, the first mixing time is 2 min to 5 min, and the rotation speed is 100 rpm to 300 rpm; in step S2, the second mixing time is 1 min to 3 min, and the rotation speed is 400 rpm to 800 rpm; preferably, before performing step S1, the preparation method of the halogen-free flame-retardant cable material composition further includes drying the resin matrix, and the drying temperature is 60±5℃, and the time is 12±2h.

[0016] A third aspect of the present invention provides the application of the above-described halogen-free flame-retardant cable material composition as an insulation material, sheathing material, or filler material for wires and cables in the power, communications, photovoltaic, and nuclear power fields.

[0017] By applying the technical solution of this invention, based on green halogen-free flame retardant technology, and by optimizing the composition of cable materials, improving the treatment method of charring agents, and enhancing the internal synergistic effect of materials, the flame retardant performance and charring effect of cable materials are improved. This achieves the technical effects of significantly reducing smoke generation, enhancing flame retardant effect, improving the mechanical strength of char layer, maintaining good mechanical and processing properties of cable materials, and reducing potential hazards to the environment and human health under fire conditions. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0019] As described in the background section, existing cable materials suffer from the problem of simultaneously possessing good mechanical properties, bending resistance, thermal stability, and flame retardant properties. To address these technical problems, a first aspect of the present invention provides a halogen-free flame-retardant cable material composition, comprising, by weight: 10-15 parts of a resin matrix, 15-35 parts of a compatibilizer, 45-65 parts of a flame retardant, 1-5 parts of a charring agent, 0.05-0.5 parts of a silane coupling agent, 0.1-3 parts of carbon black masterbatch, 0.1-2 parts of a silicone masterbatch, and 0.1-1 parts of an antioxidant; the charring agent is modified montmorillonite, and the modifier used for the montmorillonite is a biomass intercalating agent.

[0020] This invention, while avoiding the use of halogens and toxic additives in traditional flame-retardant systems, achieves improved flame-retardant performance and charring effect of cable materials by optimizing cable material composition, improving charring agent treatment methods, and enhancing internal synergistic effects. In the halogen-free flame-retardant cable material composition provided by this invention, the modified montmorillonite charring agent, in particular, can be better dispersed in the resin matrix, forming a more continuous and dense char layer. This char layer effectively blocks the transfer of oxygen and heat during combustion, inhibiting the combustion reaction and thus significantly improving the flame-retardant performance of the material.

[0021] Montmorillonite, a common mineral, has a layered structure with adjustable interlayer spacing, allowing it to accommodate various organic or inorganic molecules. This characteristic makes it an ideal candidate material for charring agents. However, unmodified montmorillonite is often difficult to disperse uniformly in polymer materials, limiting its application in composite materials. Based on this, this invention modifies montmorillonite using a biomass intercalating agent, overcoming the limitations of traditional charring agents and innovatively improving the overall performance of cable materials. Specifically, biomass intercalating agents, such as natural surfactants like lecithin extracted from plants, differ from traditional quaternary ammonium salts like cetyltrimethylammonium bromide, exhibiting significant advantages in environmental friendliness and biocompatibility. The chemical bonding between the biomass intercalating agent and montmorillonite not only enhances the stability of montmorillonite itself but also forms a more robust char layer during combustion. This enhanced mechanical strength of the char layer effectively resists physical deformation and chemical erosion under high-temperature conditions, maintaining its ability to block oxygen and heat, thereby extending flame retardant time and reducing combustion residue. The interlayering effect of modified montmorillonite helps to form a complex labyrinthine structure inside the resulting cable material. This structure increases the complexity of the heat transfer path and the resistance to heat transfer during combustion, thereby slowing down the combustion rate and reducing the emission of smoke and toxic gases.

[0022] In summary, this invention, based on montmorillonite modified with a biomass intercalator, provides a halogen-free flame-retardant cable material composition with excellent char-forming properties and flame-retardant effects. The resulting cable material composition exhibits good mechanical properties, bending resistance, low-smoke halogen-free flame retardancy, and high-temperature resistance, making it widely applicable in the wire and cable industry. In application, it achieves the technical effects of significantly reducing smoke generation under fire conditions, enhancing flame-retardant effects, improving the mechanical strength of the char layer, maintaining good mechanical and processing properties, and reducing potential hazards to the environment and human health.

[0023] Furthermore, the biomass intercalating agent is selected from one or more bio-based amphiphilic molecules. To avoid ambiguity, the amphiphilic molecules mentioned in this invention include a hydrophilic end and a hydrophobic end in their molecular structure. Based on this, the hydrophobic tail of the bio-based amphiphilic molecule tends to embed into the interlayer of montmorillonite, while the hydrophilic head faces outward. This not only more effectively increases the interlayer spacing of montmorillonite but also further improves its interfacial compatibility with the polymer matrix, promoting the uniform distribution and stable existence of the charring agent in the cable material composition. Ultimately, this leads to the formation of a denser and more continuous char layer during the charring process, resulting in a stronger barrier effect against oxygen and heat, thereby significantly improving the flame retardant effect of the cable material composition. In practical applications, the biomass intercalating agent can be selected from one or more of plant-based lecithin, L-ascorbic acid palmitate, plant-based sphingosine, and plant-based saponins. Lecithin, as a typical amphiphilic small molecule, can generate more effective chemical interactions between montmorillonite layers, forming a stable intercalation structure. This results in more uniform dispersion of montmorillonite in the resin matrix, and a denser, more complete, and more ordered carbon layer structure during the carbonization process. It can even form a labyrinthine physical barrier network, ultimately leading to better overall performance of the resulting cable material. Therefore, plant-based lecithin, extracted from soybeans, is a more preferred biomass intercalating agent.

[0024] In several typical embodiments, the char-forming agent is prepared by the following steps: Step A1, montmorillonite and biomass intercalating agent are mixed at a weight ratio of (3~6):1 and dispersed to obtain a mixed product; preferably, the dispersion treatment is carried out by ball milling at a speed of 500±50 rpm for 4±1 h; Step A2, the mixed product is calcined at a temperature of 260℃~310℃ for 1 h~3 h to obtain the char-forming agent. The (3~6):1 weight ratio allows the biomass intercalating agent to penetrate more fully into the interlayer of montmorillonite, achieving more effective chemical modification, while avoiding excessive amounts that could degrade material properties. The dispersion treatment conditions imply high-energy mechanical stress, thereby directly enabling the biomass intercalating agent to undergo a solid-phase reaction with montmorillonite, achieving an intercalation effect that is difficult to achieve with traditional liquid-phase methods, and significantly improving the stability and uniformity of the modified montmorillonite. This effectively removes the layered structure of montmorillonite, enabling the insertion of intercalating agent molecules and achieving a uniform intercalation effect that is difficult to achieve with traditional liquid-phase methods, ultimately yielding an intercalated composite product. The final optimal calcination temperature is 260℃~310℃ for 1h~3h, which removes moisture and unstable components from the biomass intercalating agent while further promoting the chemical bonding between the montmorillonite layers and the intercalating agent, forming a more stable and dense intercalated structure. This significantly improves the char-forming properties of the modified montmorillonite in the cable material. Furthermore, in practical applications, the above dispersion treatment does not introduce any solvent and is carried out under nitrogen protection at room temperature (25±2℃).

[0025] For the resin matrix, it is preferably polyethylene with good electrical insulation, chemical stability and processing performance, and the polyethylene is metallocene linear low-density polyethylene and / or linear low-density polyethylene.

[0026] Furthermore, the compatibilizer is selected from one or more of ethylene-vinyl acetate, polyolefin elastomer, and maleic anhydride. In order to further improve the compatibility and dispersibility of modified montmorillonite and flame retardant in cable material, the compatibilizer is preferably a compatibilizer composition formed by ethylene-vinyl acetate, polyolefin elastomer, and maleic anhydride in a weight ratio of (12~18):(5~8):(1~2) (more preferably, the weight ratio of the three is (12~18):(5~8):1 to achieve better dispersion effect and achieve better overall performance).

[0027] Based on the above compatibilizer composition, a more preferred preparation method includes: step R1, where ethylene-vinyl acetate, polyolefin elastomer, and maleic anhydride are sequentially mixed and pelletized to obtain compatibilizer granules; step R2, where the compatibilizer granules are subjected to radiation treatment with a radiation dose of 10±2 kGy to obtain the compatibilizer composition; further preferably, the radiation source used for radiation treatment is a Co-60 radiation source. In this process, through the aforementioned preferred radiation dose, the generation of radiation-induced free radicals further promotes the activation of compatibilizer molecules, thereby significantly improving their interfacial compatibility and dispersibility with the resin matrix, ultimately more effectively enhancing the overall mechanical properties and flame-retardant properties of the obtained cable material composition.

[0028] Further, the flame retardant is selected from one or more of hydroxide-based and / or phosphorus-based flame retardants; specifically: hydroxide-based flame retardants include magnesium hydroxide and aluminum hydroxide; and / or, phosphorus-based flame retardants include red phosphorus, microencapsulated red phosphorus, and phosphate esters. Hydroxide-based flame retardants primarily absorb a large amount of heat by decomposing at high temperatures to generate water vapor and non-flammable metal oxides, thereby reducing the combustion temperature and producing a physical barrier effect. Phosphorus-based flame retardants, on the other hand, form a char layer by generating phosphates and phosphorus oxides, isolating oxygen and heat, and inhibiting the combustion reaction. Based on this, to achieve a synergistic enhancement of the flame retardant effect, a flame retardant composition formed by magnesium hydroxide and microencapsulated red phosphorus at a weight ratio of (40~50):1 (more preferably (45~50):1) is preferred. In the preferred flame retardant composition, magnesium hydroxide can rapidly absorb heat and generate water vapor in the early stage of combustion, effectively reducing the combustion temperature, while microencapsulated red phosphorus generates phosphate and phosphorus oxides at high temperature, forming a dense carbon layer, further isolating oxygen and heat, thereby achieving a dual enhancement of the flame retardant effect of the obtained cable material.

[0029] To ensure that the obtained halogen-free flame-retardant cable material composition can maintain better processing performance and mechanical strength while possessing excellent flame-retardant properties, in several preferred embodiments, the halogen-free flame-retardant cable material composition preferably comprises, by weight: 10 to 14 parts of resin matrix, 20 to 30 parts of compatibilizer, 50 to 60 parts of flame retardant, 1 to 5 parts of charring agent, 0.1 to 0.3 parts of silane coupling agent, 0.5 to 2 parts of carbon black masterbatch, 0.3 to 1.0 parts of silicone masterbatch, and 0.1 to 0.5 parts of antioxidant. In several more preferred embodiments, the preferred halogen-free flame-retardant cable material composition, by weight, comprises: 11.5 to 13.5 parts of polyethylene, 14 to 20 parts of ethylene-vinyl acetate, 5 to 8 parts of polyolefin elastomer, 1 to 2 parts of maleic anhydride, 48 to 60 parts of magnesium hydroxide flame retardant, 1 to 3 parts of microencapsulated red phosphorus flame retardant, 2 to 5 parts of charring agent, 0.15 to 0.25 parts of silane coupling agent, 0.8 to 1.2 parts of carbon black masterbatch, 0.4 to 0.7 parts of silicone masterbatch, and 0.3 to 0.5 parts of antioxidant.

[0030] Based on the above dosage ratios, in several particularly preferred embodiments, the preferred halogen-free flame-retardant cable material composition, by weight, comprises: 8 parts of mPE 3518CB, 4 parts of mPE XP8656, 8 parts of ethylene-vinyl acetate EVA3027FL, 8 parts of ethylene-vinyl acetate EVA EV180, 6.4 parts of polyolefin elastomer, 1 part of maleic anhydride, 58 parts of magnesium hydroxide flame retardant, 1.2 parts of microencapsulated red phosphorus flame retardant, 4 parts of charring agent, 0.2 parts of silane coupling agent, 1 part of carbon black masterbatch, 0.6 parts of silicone masterbatch, and 0.4 parts of antioxidant 1010; or, comprises: 12 parts of mPE3518CB, 8 parts of ethylene-vinyl acetate EVA 3027FL, 8 parts of ethylene-vinyl acetate EVA EV180, and 6.4 parts of polyolefin elastomer POE. The composition includes: C5070D, 1 part maleic anhydride, 58 parts magnesium hydroxide flame retardant, 1.2 parts microencapsulated red phosphorus flame retardant, 4 parts charring agent, 0.2 parts silane coupling agent, 1 part carbon black masterbatch, 0.6 parts silicone masterbatch, and 0.4 parts antioxidant 1010; or, including: 8 parts mPE 3518CB, 4 parts mPE XP8656, 16 parts ethylene-vinyl acetate EVA3027FL, 6.4 parts polyolefin elastomer POE C5070D, 1 part maleic anhydride, 58 parts magnesium hydroxide flame retardant, 1.2 parts microencapsulated red phosphorus flame retardant, 4 parts charring agent, 0.2 parts silane coupling agent, 1 part carbon black masterbatch, 0.6 parts silicone masterbatch, and 0.4 parts antioxidant 1010. In the above-mentioned preferred cable material composition formulation, the resin matrix can provide a better physical property basis, the ternary compatibilizer can more effectively promote the interfacial compatibility between the components, and the synergistic effect of the dual flame retardants and charring agents can more significantly improve the flame retardant performance and char layer stability of the cable material composition.

[0031] A second aspect of the present invention provides a method for preparing the above-mentioned halogen-free flame-retardant cable material composition, comprising: step S1, mixing a resin matrix and a compatibilizer in a first mixing process to obtain a first material; step S2, adding a flame retardant to the first material and mixing it in a second mixing process to obtain a second material; step S3, adding a charring agent to the second material to obtain a third material; and step S4, extruding and granulating the third material sequentially to obtain the halogen-free flame-retardant cable material composition.

[0032] To address the aforementioned halogen-free flame-retardant cable material composition, this invention provides a corresponding preparation method. Through stepwise mixing, direct reactions between components are avoided, allowing each component to independently and fully exert its respective function. The initial mixing of the resin matrix and compatibilizer improves the overall compatibility and processing performance of the resulting cable material composition; the secondary addition of the flame retardant enhances the flame-retardant effect; and the final addition of the charring agent promotes the formation of a denser and more continuous char layer after combustion, thereby improving flame-retardant performance. Furthermore, the preparation method provided by this invention is simple and easy to implement, enabling the preparation of high-performance halogen-free flame-retardant cable material compositions at low cost and high efficiency.

[0033] Furthermore, to promote more uniform dispersion of the components, reduce the degradation of material properties caused by over-mixing, and more effectively improve the efficiency of the preparation process, in step S1, the first mixing time is preferably 2 min to 5 min, and the rotation speed is 100 rpm to 300 rpm; in step S2, the second mixing time is preferably 1 min to 3 min, and the rotation speed is 400 rpm to 800 rpm. Also, before step S1, the preparation method of the halogen-free flame-retardant cable material composition further includes drying the resin matrix at a temperature of 60 ± 5 °C for 12 ± 2 h. This preferred additional step can more effectively remove moisture from the resin matrix, reduce material property instability caused by water vapor generation during processing, and also create better conditions for subsequent mixing, ultimately significantly improving the uniformity and stability of the obtained cable material composition.

[0034] A third aspect of this invention provides an application of the above-mentioned halogen-free flame-retardant cable material composition as an insulation layer material, sheathing layer material, or filler material for wires and cables in the power, communications, photovoltaic, and nuclear power fields. The cable material composition of this invention, by optimizing the ratio of flame retardant, compatibilizer, charring agent, and resin matrix, combined with the special functions of modified montmorillonite, can further optimize the heat resistance, environmental friendliness, and comprehensive physical properties of the material while meeting the requirements of flame retardancy. It is suitable for insulation layers, sheathing layers, or filler materials for various wires and cables, demonstrating its broad application prospects in multiple fields.

[0035] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0036] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0037] Example 1

[0038] A method for preparing a halogen-free flame-retardant cable material composition:

[0039] The components of the halogen-free flame-retardant cable material composition selected in this embodiment are:

[0040] Eight parts of metallocene linear low-density polyethylene (ExxonMobil mPE 3518CB) and four parts of metallocene linear low-density polyethylene (ExxonMobil mPE XP8656) were used as the resin matrix.

[0041] Eight parts of ethylene-vinyl acetate (ExxonMobil EVA 3027FL), eight parts of ethylene-vinyl acetate (Mitsui Chemicals EVA EV180), 6.4 parts of polyolefin elastomer (POE, Dow Chemical POE C5070D) and one part of maleic anhydride (MAH, manufactured by Zibo Qixiang Tengda Chemical) were used together as a compatibilizer composition.

[0042] 58 parts of magnesium hydroxide flame retardant (Jiangsu Zhuofeng 22-A) and 1.2 parts of microencapsulated red phosphorus flame retardant (MRP, manufacturer's model: Suzhou Century Fuxiang SJFX-60) were used together as a flame retardant composition.

[0043] 4 parts of charring agent;

[0044] 0.2 parts of silane coupling agent (Jiacheng JC-750);

[0045] 1 part carbon black masterbatch (Cabot PE2772);

[0046] 0.6 parts silicone masterbatch (Zhejiang Jiahua GT-500);

[0047] 0.4 parts of antioxidant 1010 (manufacturer: Tianjin Lialong).

[0048] The contents of the above components are shown in Table 1-1, and one “part” is actually kg.

[0049] First, the preparation of the compatibilizer composition:

[0050] (R1) Place EVA, POE, and MAH in a vacuum drying oven and dry at 60°C for 12 hours; take the dried EVA, POE, and MAH, mix them evenly, extrude them in a twin-screw extruder, pelletize them, and dry them;

[0051] (R2) The granules after cutting were vacuum packaged on a vacuum packaging machine and then irradiated in a Co-60 radiation source irradiation chamber with a radiation dose of 10 kGy to obtain a compatibilizer composition.

[0052] Secondly, the preparation of the charring agent:

[0053] (A1) 2500g of montmorillonite and 500g of lecithin (extracted from soybeans, manufactured by Shanghai Yuanye Biotechnology Co., Ltd.) were mixed and dispersed under nitrogen protection and at room temperature. Specifically, in the absence of solvents, high-energy mechanical stress was applied using a high-energy ball mill (500 rpm, 4 hours) to directly induce a solid-phase reaction between lecithin, a green intercalating agent, and montmorillonite. This method effectively exfoliates the layered structure of montmorillonite, enabling the insertion of lecithin molecules and achieving a uniform intercalation effect that is difficult to achieve using traditional liquid-phase methods, ultimately yielding an intercalated composite product.

[0054] (A2) Under a nitrogen atmosphere, the resulting mixed product was calcined at 300°C for 2 hours to obtain a char-forming agent.

[0055] The above-mentioned modification process is referred to as process 1.

[0056] Finally, the halogen-free flame-retardant cable material composition was prepared as follows:

[0057] (S1) Place the weighed polyethylene resin matrix in a vacuum drying oven, adjust the temperature to a constant 60℃, and dry for 12 hours. Then add the polyethylene resin matrix and compatibilizer to a high-speed mixer and mix at 200 rpm for 3 minutes to obtain the first material.

[0058] (S2) First, the two halogen-free flame retardants are mixed evenly to obtain a mixed flame retardant; then the flame retardant is added to a mixer and mixed at 800 rpm for 2 min to obtain the second material.

[0059] (S3) Then add the charring agent and mix evenly to obtain the third material;

[0060] (S4) The uniformly blended mixture is then extruded in an extruder and granulated to obtain a halogen-free flame-retardant cable material composition.

[0061] Examples 2 to 7

[0062] The only difference between Examples 2 to 7 and Example 1 is that the content of each component in the halogen-free flame-retardant cable material composition is different, as detailed in Table 1-1.

[0063] Example 8

[0064] A method for preparing a halogen-free flame-retardant cable material composition:

[0065] The only difference between this embodiment and Example 1 is that no radiation treatment was performed during the preparation of the compatibilizer composition. The content of each component is shown in Table 1-1.

[0066] Example 9

[0067] A method for preparing a halogen-free flame-retardant cable material composition:

[0068] The only difference between this embodiment and Embodiment 1 is that, in the preparation process of modified montmorillonite, an equal weight of tannic acid is used instead of lecithin.

[0069] The content of each component in the halogen-free flame-retardant cable material composition is consistent with that in Example 1.

[0070] Example 10

[0071] A method for preparing a halogen-free flame-retardant cable material composition:

[0072] The only difference between this embodiment and Embodiment 1 is that, in the preparation process of modified montmorillonite, an equal weight of cellulose is used instead of lecithin.

[0073] The content of each component in the halogen-free flame-retardant cable material composition is consistent with that in Example 1.

[0074] Example 11

[0075] A method for preparing a halogen-free flame-retardant cable material composition:

[0076] The only difference between this embodiment and Embodiment 1 is that the amount of montmorillonite used in the preparation of modified montmorillonite is changed to 1000g, and the weight ratio of montmorillonite to lecithin is changed to 2:1 (this process is referred to as Process 2).

[0077] Example 12

[0078] A method for preparing a halogen-free flame-retardant cable material composition:

[0079] The only difference between this embodiment and Embodiment 1 is that, in the preparation process of modified montmorillonite, the ball milling speed is changed to 200 rpm, and the calcination temperature is changed to 250℃ (this process is referred to as Process 3).

[0080] Comparative Example 1

[0081] A method for preparing a cable material composition:

[0082] The only difference between this comparative example and Example 1 is that no carbonizing agent was added to the cable material composition formulation, as detailed in Table 1.

[0083] Comparative Example 2

[0084] A method for preparing a cable material composition:

[0085] The only difference between this comparative example and Example 1 is that an equal weight of montmorillonite is used instead of the char-forming agent in Example 1, as detailed in Table 1.

[0086] Comparative Example 3

[0087] A method for preparing a cable material composition:

[0088] The only difference between this comparative example and Example 1 is that, in the preparation of the modified montmorillonite, an equal weight of hexadecyltrimethylammonium bromide was used instead of lecithin.

[0089] The content of each component in the cable material composition formula remains the same as in Example 1.

[0090] The component contents of Examples 9 to 12 and Comparative Examples 1 to 3 are shown in Tables 1-2.

[0091] Table 1-1

[0092]

[0093] Table 1-2

[0094]

[0095] Test methods

[0096] First, samples were prepared by molding, and the cable material compositions obtained in each embodiment and comparative example were prepared into test strips. The samples were plasticized and sheeted on a plasticizer at a temperature of 120~140℃; then preheated without pressure for 10 min in a hydraulic press and then pressurized for 5 min at a temperature of 165~175℃ to ensure that the material was fully plasticized and did not decompose during processing. The pressure of the hydraulic press should not be less than 15 MPa, and then the samples were pressurized and cooled to room temperature.

[0097] Mechanical property testing: The tensile strength and elongation at break of the specimens obtained in each example and comparative example were determined on an HDW-2000 microcomputer-controlled rubber tensile testing machine in accordance with the GB / T 1040.1-2018 standard; five specimens were tested for each material and the average value was calculated.

[0098] Thermal aging test: The test specimens are treated at a constant temperature of 110±2℃ in an air thermal aging chamber for 240 h. The test specimens are suspended vertically in the middle of the chamber, and the spacing between the test specimens is not less than 20 mm. The total number of air replacements in the chamber is not less than 8 times and not more than 20 times per hour.

[0099] UL 94 Vertical Flammability Rating Test: The UL 94 vertical flammability ratings of the samples obtained from each example and comparative example were tested using a horizontal and vertical flammability tester (CZF-5) according to GB / T 2408-2008 standard. In the rating results, regarding flame retardant performance, V0 > V1 > V2; NC is the worst, indicating failure to pass the UL 94 test.

[0100] Limiting Oxygen Index (LOI) Test: The LOI of the specimens obtained from the examples and comparative examples was tested on a JF-5 limiting oxygen index (LOI) tester according to GB / T 2406.2-2009 standard. The higher the value, the better the flame retardant effect of the specimen.

[0101] The test results are shown in Table 2.

[0102] Table 2

[0103]

[0104] As can be seen from the above description, compared with the comparative examples, the embodiments of the present invention, especially Examples 1 to 3, have achieved the preparation of a high-performance halogen-free flame-retardant cable material composition. The resulting halogen-free flame-retardant cable material composition not only has good mechanical properties but also excellent charring properties. In particular, the charring agent can further improve the density and continuity of the char layer, resulting in a more stable and dense structure of the combustion residue. This means that under fire conditions, it can fully exert its flame-retardant properties, effectively limiting the spread of flames and the generation of smoke. At the same time, the cable material provided by the present invention avoids the addition of halogen-containing flame retardants, reducing the adverse effects of halogen-containing flame retardants on human health and the environment.

[0105] Specifically, in each embodiment:

[0106] Comparing Examples 5 and 6 with Example 1, it can be seen that by gradually optimizing the specific composition of the flame retardant, a synergistic enhancement of the flame retardant effect can be achieved, thereby further strengthening the flame retardant effect of the obtained cable material.

[0107] Comparing Example 7 with Example 1, it can be seen that by optimizing the specific composition of the compatibilizer, the compatibility and dispersibility of modified montmorillonite and flame retardant in cable material can be further improved, thereby obtaining a halogen-free flame retardant cable material composition with better flame retardant performance.

[0108] Comparing Example 8 with Example 1, it can be seen that further radiation treatment of the compatibilizer composition can promote the activation of compatibilizer molecules, thereby significantly improving its interfacial compatibility and dispersibility with the resin matrix, and ultimately more effectively enhancing the overall mechanical properties and flame retardant properties of the obtained cable material composition.

[0109] Comparing Examples 9 and 10 with Example 1, it can be seen that by optimizing the specific type of intercalating agent, a stable intercalation structure can be formed, thereby making the montmorillonite more uniformly dispersed in the resin matrix, and the carbon layer structure during the carbonization process is more dense, complete and orderly, and can even form a maze-like physical barrier network, ultimately resulting in better overall performance of the obtained cable material.

[0110] Comparing Examples 11 and 12 with Example 1, it can be seen that by optimizing the char-forming agent, i.e. the condition parameters in the preparation process of modified montmorillonite, a more stable and dense intercalation structure can be formed, thereby significantly improving the char-forming performance of the cable material containing modified montmorillonite.

[0111] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0112] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A halogen-free flame-retardant cable material composition, characterized in that, By weight, the halogen-free flame-retardant cable material composition comprises: 10 to 15 parts of resin matrix, 15 to 35 parts of compatibilizer, 45 to 65 parts of flame retardant, 1 to 5 parts of charring agent, 0.05 to 0.5 parts of silane coupling agent, 0.1 to 3 parts of carbon black masterbatch, 0.1 to 2 parts of silicone masterbatch, and 0.1 to 1 part of antioxidant; The char-forming agent is modified montmorillonite, and the modifier used to modify the montmorillonite is a biomass intercalating agent.

2. The halogen-free flame-retardant cable material composition according to claim 1, characterized in that, The biomass intercalating agent is one or more of bio-based amphiphilic molecules, and the molecular structure of the bio-based amphiphilic molecule includes a hydrophilic end and a hydrophobic end. Preferably, the biomass intercalating agent is selected from one or more of plant-based lecithin, L-ascorbyl palmitate, plant-based sphingosine, and plant-based saponins.

3. The halogen-free flame-retardant cable material composition according to claim 1 or 2, characterized in that, The char-forming agent is prepared by the following steps: Step A1: The montmorillonite and the biomass intercalating agent are mixed at a weight ratio of (3~6):1 and dispersed to obtain a mixed product; preferably, the dispersion is carried out by ball milling at a speed of 500±50 rpm and the dispersion time is 4±1 h. Step A2: The mixed product is calcined at a temperature of 260℃~310℃ for 1h~3h to obtain the char-forming agent.

4. The halogen-free flame-retardant cable material composition according to any one of claims 1 to 3, characterized in that, The resin matrix is ​​polyethylene, and the polyethylene is metallocene linear low-density polyethylene and / or linear low-density polyethylene.

5. The halogen-free flame-retardant cable material composition according to any one of claims 1 to 4, characterized in that, The compatibilizer is selected from one or more of ethylene-vinyl acetate, polyolefin elastomers, and maleic anhydride; Preferably, the compatibilizer is a compatibilizer composition formed by the ethylene-vinyl acetate, the polyolefin elastomer, and the maleic anhydride in a weight ratio of (12~18):(5~8):(1~2).

6. The halogen-free flame-retardant cable material composition according to any one of claims 1 to 5, characterized in that, The flame retardant is selected from one or more of hydroxide-based flame retardants and / or phosphorus-based flame retardants; Preferably, the hydroxide-based flame retardant includes magnesium hydroxide and aluminum hydroxide; and / or, the phosphorus-based flame retardant includes red phosphorus, microencapsulated red phosphorus, and phosphate esters.

7. The halogen-free flame-retardant cable material composition according to any one of claims 1 to 6, characterized in that, By weight, the halogen-free flame-retardant cable material composition comprises: 10 to 14 parts of the resin matrix, 20 to 30 parts of the compatibilizer, 50 to 60 parts of the flame retardant, 1 to 5 parts of the charring agent, 0.1 to 0.3 parts of the silane coupling agent, 0.5 to 2 parts of the carbon black masterbatch, 0.3 to 1.0 parts of the silicone masterbatch, and 0.1 to 0.5 parts of the antioxidant; Preferably, the halogen-free flame-retardant cable material composition comprises, by weight: 11.5 to 13.5 parts of polyethylene, 14 to 20 parts of ethylene-vinyl acetate, 5 to 8 parts of polyolefin elastomer, 1 to 2 parts of maleic anhydride, 48 to 60 parts of magnesium hydroxide flame retardant, 1 to 3 parts of microencapsulated red phosphorus flame retardant, 2 to 5 parts of charring agent, 0.15 to 0.25 parts of the silane coupling agent, 0.8 to 1.2 parts of the carbon black masterbatch, 0.4 to 0.7 parts of the silicone masterbatch, and 0.3 to 0.5 parts of the antioxidant.

8. A method for preparing a halogen-free flame-retardant cable material composition according to any one of claims 1 to 7, characterized in that, include: Step S1: The resin matrix and the compatibilizer are mixed for the first time to obtain the first material; Step S2: The flame retardant is added to the first material, and after a second mixing, a second material is obtained; Step S3: Add the charring agent to the second material to obtain the third material; In step S3, the third material is extruded and granulated sequentially to obtain the halogen-free flame-retardant cable material composition.

9. The method for preparing the halogen-free flame-retardant cable material composition according to claim 8, characterized in that, In step S1, the first mixing time is 2 min to 5 min, and the rotation speed is 100 rpm to 300 rpm. In step S2, the second mixing time is 1 min to 3 min, and the rotation speed is 400 rpm to 800 rpm; Preferably, before performing step S1, the preparation method of the halogen-free flame-retardant cable material composition further includes drying the resin matrix, wherein the drying temperature is 60±5℃ and the time is 12±2h.

10. The application of any one of the halogen-free flame-retardant cable material compositions according to claims 1 to 7 as an insulation material, sheathing material or filler material for wires and cables in the power, communications, photovoltaic and nuclear power fields.

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