A low-temperature-resistant multi-layer insulation blanket for live working in high-altitude cold areas and its preparation method

Abstract

The present invention provides a low-temperature resistant multi-layer insulation blanket for live working in high-altitude cold areas and a preparation method thereof, relating to the technical field of insulation materials for power equipment. The insulation blanket adopts a multi-layer structure, with the upper and lower layers being a composite of modified EVA film and nylon fiber mesh cloth, the middle being a stack of multiple layers of modified EVA film, and the edges being sealed by high-frequency welding. A self-made cold-resistant toughening resin is introduced into the modified EVA film of the insulation blanket, and the synergy of multiple components such as metal gallium nanodispersion and ionic liquid greatly improves the flexibility, mechanical strength and insulation performance of the material in an extremely cold environment of ‑40°C, which is significantly better than conventional EVA or rubber-based materials. The preparation process of the insulation blanket of the present invention is simple, and the finished product is pressure-resistant without breakdown or cracking at extremely low temperatures, meeting the safety and reliability requirements of live working in high-altitude cold areas of the power system, and has broad prospects for promotion and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of insulating materials for electric power equipment, and in particular relates to a low-temperature-resistant multi-layer insulating blanket for live working in high-altitude cold areas and a preparation method thereof. Background Art

[0002] Insulation blankets are critical protective equipment for non-stop power distribution network operations. Their adaptability to low-temperature environments directly impacts the safety of live-line operations in high-altitude and cold regions. Currently, commercially available insulation blankets are primarily ethylene-vinyl acetate (EVA)-based and rubber-based. However, both exhibit significant deficiencies in extreme cold conditions of -40°C and below. While EVA-based insulation blankets offer advantages such as lightweight and room-temperature flexibility, their molecular chain mobility decreases dramatically with decreasing temperature. When ambient temperatures fall below -20°C, the material's insufficient glass transition temperature (GTT) becomes more pronounced, leading to increased embrittlement and prone to cracking and failure under mechanical stress. While rubber-based insulation blankets offer high low-temperature strength, their hardness increases exponentially with decreasing temperature, significantly degrading their flexibility and conformability to the encased equipment, making them susceptible to protective gaps during actual operations. Both types of products exhibited structural cracks after a 100N pressure test at -40°C, failing to meet the low-temperature mechanical integrity requirements specified in the DL / T 803-2015 standard.

[0003] The electrical insulation performance of existing insulation blankets systematically degrades in low-temperature environments. EVA-based materials experience increased molecular polarity due to plasticizer migration and an increased proportion of crystalline regions, leading to increased carrier mobility. Rubber-based materials, on the other hand, experience microcracks due to shrinkage of the cross-linked network, which can easily form local discharge channels. Industry test data shows that the AC withstand voltage of conventional products generally drops below 28kV at -40°C. This is not only below the standard threshold of 30kV / 3min, but also poses a risk of surface flashover, making it difficult to guarantee insulation reliability for live operations on 10kV distribution lines in high-altitude and cold regions. Furthermore, multi-layer composite insulation blankets generally utilize hot-melt adhesive bonding or conventional hot pressing processes, and the resulting lack of interfacial bonding strength is exposed during temperature cycling. Differences in thermal expansion coefficients between the nylon fiber mesh and the matrix resin lead to interlayer separation, while edge sealing processes often rely on sewing or gluing, resulting in structural defects such as exposed fibers and burrs. Moisture penetration along the edges accelerates material aging.

[0004] Under long-term outdoor use, the durability issues of existing insulation blankets are further exacerbated. Ultraviolet radiation triggers rapid consumption of antioxidants, which, combined with thermal oxidative aging, leads to material pulverization and cracking. Industry research shows that distribution network operations in high-altitude cold regions in China currently rely primarily on imported insulation blankets, but these still face bottlenecks such as insufficient low-temperature adaptability and high unit prices. With the DL / T803-2015 standard raising performance requirements for insulation blankets in extremely cold environments, developing domestically produced products that combine low-temperature brittle crack resistance, high insulation strength, and long-term weather resistance has become a technical challenge that the industry urgently needs to overcome. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a low-temperature resistant multi-layer insulation blanket for live working in extremely cold areas and a preparation method thereof. The insulation blanket of the present invention maintains excellent flexibility, high insulation reliability and long-term anti-delamination performance even in a harsh environment of -40°C, and fully meets the technical requirements of the DL / T 803-2015 standard for insulation protection equipment for live working on 10kV distribution lines in extremely cold areas.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a modified EVA film for a low-temperature-resistant multi-layer insulation blanket for live working in high-altitude cold areas. The raw materials for preparing the film include, by mass percentage, 70% to 78% of EVA resin, 15% to 21% of cold-resistant toughening resin, 0.6% to 0.8% of cross-linking agent, 1.5% to 2.0% of plasticizer, 0.18% to 0.22% of vulcanizing agent, 2.0% to 3.0% of titanium dioxide, 1.5% to 2% of compatibilizer, 0.5% to 1% of ultraviolet absorber, and 0.30% to 0.37% of composite antioxidant.

[0008] Furthermore, the cold-resistant toughening resin is prepared according to the following steps:

[0009] (1) Metal gallium is mixed with sodium dodecylsulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate and deionized water, and ultrasonication is applied to obtain a nano-dispersion liquid;

[0010] (2) mixing POE resin, maleic anhydride grafted POE (MAH-g-POE), antioxidant 1010 and the nano-dispersion obtained in step (1) to obtain a premix;

[0011] (3) The premix is ​​put into an internal mixer and mixed at 120-140°C for 10-20 minutes. After discharging, the premix is ​​cooled and pelletized to obtain a cold-resistant toughened resin.

[0012] Furthermore, the mass ratio of the metal gallium, sodium dodecylsulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and deionized water in step (1) is 1: (8-12): (8-12): (300-400).

[0013] Furthermore, in step (2), the mass ratio of the POE resin, maleic anhydride grafted POE (MAH-g-POE), antioxidant 1010, and nano-dispersion liquid is 100: (2-3): (0.15-0.25): (0.3-1).

[0014] The cold-resistant toughening resin prepared by this invention plays a key role in enhancing flexibility and stabilizing the structure of multi-layer insulation blankets used for live-line work in high-altitude cold regions. It is a key component in ensuring the material's long-term service life in extremely low-temperature environments, achieving high insulation and reliability. By incorporating multiple functional components, including a metal gallium nanodispersion, an ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate), a surfactant (sodium dodecylsulfonate), and a polar grafted polymer, this resin system overcomes the inherent bottleneck of conventional POE / EVA systems at the molecular level, which restricts molecular chain mobility and significantly reduces mechanical properties at low temperatures. Liquid metal nanoclusters are highly dispersed between polymer segments, forming localized compliant soft zones and generating a synergistic interfacial regulation effect with the polar organic phase. This allows the polymer chains to maintain high activation and energy dissipation capabilities even in extremely cold conditions, such as -40°C, significantly reducing the risk of embrittlement and fracture. At the same time, the introduction of ionic liquids and surfactants effectively improves the dispersion stability of the metal nanoclusters, enhancing the interfacial compatibility between the toughening resin and the EVA matrix and other polar components, thereby strengthening the interlayer bonding within the composite material and significantly reducing the probability of failure such as delamination and shedding of the multilayer insulation blanket under thermal cycling and mechanical shock. Furthermore, this cold-resistant toughening resin formula balances electrical insulation and long-term material stability. The metal component is used in extremely low amounts and is evenly coated within the polymer network, preventing the formation of conductive pathways and maintaining overall insulation performance.

[0015] Furthermore, the cross-linking agent is triallyl isocyanurate (TAIC), potassium persulfate (KPS), azobisisobutyronitrile (AIBN), bismaleimide (BMI) or pentaerythritol tetraacrylate (PETEA).

[0016] Furthermore, the vulcanizing agent is dicumyl peroxide (DCP), benzoyl peroxide (BPO), diisobutylbenzene peroxide (DICP) or tert-butyl perbenzoate (TBPE).

[0017] Furthermore, the plasticizer is dioctyl sebacate (DOS), dioctyl phthalate (DOP), dibutyl phthalate (DBP), diisononyl diphenyl dicarboxylate (DINP) or diisodecyl diphenyl dicarboxylate (DIDP).

[0018] Furthermore, the compatibilizer is maleic anhydride grafted POE (MAH-g-POE).

[0019] Furthermore, the ultraviolet absorber is UV326, UV-366, UV-327, UV-328, UV-329 or ultraviolet absorber TINUVIN1171 (CIBA).

[0020] Furthermore, the composite antioxidant includes antioxidant 1010, antioxidant 1076 and antioxidant 168 in a mass ratio of 1:(6-9):(9-15).

[0021] In the formula of the present invention, EVA resin serves as a matrix, providing the necessary flexibility and a good electrical insulation foundation for the entire system. However, when used alone, it is prone to brittleness and decreased mechanical properties under extremely cold conditions. The introduction of cold-resistant toughening resin effectively makes up for this shortcoming. This special resin system, through multi-component nano-dispersion, polar chain segment design and structural regulation, enables the material to still have a high molecular chain activity ability in extreme low temperature environments such as -40°C, and greatly reduces the glass transition temperature. The highly dispersed liquid metal clusters and the organic phase interface work together to form local flexible areas, which bring excellent impact resistance and ductility to the system, and also improve the tear and puncture strength. At the same time, the cross-linking agent and the vulcanizing agent work together to help the molecular chains moderately connect into a three-dimensional network, taking into account structural stability and flexibility, and avoiding the phenomenon of material hardening and easy breakage caused by excessive cross-linking. The reasonable addition of plasticizer further improves the flexibility of the material at low temperatures and ensures the stable performance of the material in complex mechanical stress and temperature cycles. The compatibilizer builds an effective molecular bridge between organic components of different polarities and inorganic reinforcements, thereby enhancing the bonding force between the phases and effectively preventing failure problems such as delamination and interface peeling in the multilayer structure. In addition, the collaborative design of the ultraviolet absorber and the composite antioxidant enables the material to maintain long-term stability of mechanical and electrical properties under long-term plateau, strong ultraviolet and snowy environments. Titanium dioxide not only gives the material excellent light-shielding properties and appearance, but also acts as a physical barrier, further improving the weather resistance of the material. Overall, the formula design of the present invention achieves systematic synergy in terms of microstructure, interface bonding, anti-aging and other aspects, so that the modified EVA film of the insulation blanket material exhibits the comprehensive advantages of high flexibility, high strength, high insulation and long-term reliability in harsh environments.

[0022] A second aspect of the present invention provides a method for preparing the modified EVA film for the above-mentioned low-temperature-resistant multi-layer insulation blanket for live working in high-altitude cold areas, comprising the following steps:

[0023] (1) Place EVA resin, cold-resistant toughening resin, and compatibilizer in a mixer and mix at 55±5°C for 5-15 minutes to obtain a premix;

[0024] (2) Transfer the premix to an internal mixer, add a crosslinker, plasticizer, vulcanizer, titanium dioxide, UV absorber, and composite antioxidant, and mix at 120±10°C for 10-20 minutes to form a homogeneous rubber mix;

[0025] (3) The mixed rubber is made into a modified EVA film through extrusion casting or calendering process.

[0026] The third aspect of the present invention provides a low-temperature resistant multi-layer insulation blanket for live working in high-altitude and cold areas, comprising an upper insulating outer layer, an intermediate insulating layer and a lower insulating outer layer stacked in layers; the upper insulating outer layer and the lower insulating outer layer are both composite structures, and the composite structure includes nylon fiber mesh cloth and a modified EVA film composited on both sides of the nylon fiber mesh cloth; the intermediate insulating layer is composed of multiple layers of modified EVA film stacked together.

[0027] Furthermore, the intermediate insulating layer is composed of 8 to 12 layers of modified EVA films stacked together.

[0028] Furthermore, the four sides of the upper insulating outer layer, the middle insulating layer and the lower insulating outer layer are sealed and fixed by high-frequency welding.

[0029] A fourth aspect of the present invention provides a method for preparing the above-mentioned low-temperature resistant multi-layer insulation blanket for live working in cold regions, comprising the following steps:

[0030] (1) stacking two layers of modified EVA film and a layer of nylon fiber mesh cloth in the order of modified EVA film, nylon fiber mesh cloth, and modified EVA film, and performing hot pressing to obtain a modified EVA film / nylon fiber mesh cloth / modified EVA film composite structure as an upper insulating outer layer and a lower insulating outer layer;

[0031] (2) Stack 8 to 12 layers of modified EVA film as the middle insulation layer, and align them in the order of lower insulation outer layer, middle insulation layer, and upper insulation outer layer. Use high-frequency welding equipment to pressurize and weld the four sides so that the materials at the edge are fused and sealed together;

[0032] (3) Velcro components are arranged at equal intervals around the edge sealing, including hook-surface Velcro and velvet-surface Velcro, and the positions correspond to each other, thereby obtaining the low-temperature resistant multi-layer edge blanket for live-line working in high-altitude cold areas.

[0033] Furthermore, the welding pressure in step (2) is 0.4-0.8 MP, and the welding time is 1-4 seconds.

[0034] The insulation blanket of this invention utilizes an innovative sandwich design, combining multiple layers of modified EVA film and nylon fiber mesh. The upper and lower insulating outer layers utilize a "film-fiber-film" structure, effectively enhancing the mechanical toughness and tear resistance of the surface layer. Furthermore, the stacking of multiple layers of modified EVA film in the middle effectively buffers and disperses mechanical shock and extreme cold stress. This sandwich-like, multi-layer composite structure not only enhances the overall strength and flexibility of the insulation blanket, but also significantly improves interlayer bonding, significantly reducing the risk of delamination and peeling caused by sudden temperature fluctuations or prolonged unwinding.

[0035] High-frequency welding replaces traditional sewing and gluing in the finished product assembly and edge-sealing process. This welding method offers advantages such as uniform heating, thorough fusion, and efficient operation. It creates a dense, fused seal around the blanket, effectively preventing moisture, dust, and impurities from penetrating the edges. This extends the insulation blanket's service life and improves its long-term stability in harsh environments. The Velcro design enhances the blanket's adaptability and practicality in the field, facilitating quick installation, removal, and repeated use, meeting the requirements for safe, convenient, and flexible operation in live-line work settings.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention innovatively introduces a self-made cold-resistant toughening resin and a multi-component collaborative design, so that the insulation blanket still has high flexibility, high strength and excellent electrical insulation performance in an extremely cold environment of -40°C. Compared with the existing technology, the product of the present invention significantly improves the resistance to brittle cracking, tearing and puncture, effectively preventing the insulation blanket from breaking, delamination and failure during extremely low temperature operations, and extending its service life. At the same time, the preparation process is simple, and all raw materials are commercially available products, which are easy to promote and apply. This material can be widely used in live operations in cold and high-altitude areas of the power system, providing a strong guarantee for the safe and reliable operation of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention is a preparation flow chart of a low-temperature resistant multi-layer insulation blanket for live working in high-altitude cold areas.

[0039] Figure 2 The present invention is a schematic top view of the structure of a low-temperature resistant multi-layer insulation blanket for live working in cold areas.

[0040] Figure 3 This is a schematic diagram of the overall structure of a low-temperature resistant multi-layer insulation blanket for live working in cold areas according to the present invention.

[0041] Figure 4 This is a schematic side view of the structure of a low-temperature resistant multi-layer insulation blanket for live working in cold areas according to the present invention.

[0042] Figure numerals: 1-hook surface Velcro, 2-suede surface Velcro, 3-hook surface Velcro, 4-suede surface Velcro, 5-hook surface Velcro, 6-suede surface Velcro, 7-upper insulating outer layer, 8-middle insulating layer, 9-lower insulating outer layer. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise belong to the scope of protection of the present invention. In addition, it is worth noting that the raw materials involved in the present invention are all common commercially available products unless otherwise specified.

[0044] The following raw material sources are illustrative:

[0045] EVA resin, sourced from DuPont Chemical, is branded Elvax 260. It has a vinyl acetate (VA) content of 30%, a melt index of 2-5 g / 10 min (190°C, 2.16 kg), and a density of 0.92-0.94 g / cm 3 ;

[0046] POE8180 is an ethylene-octene copolymer produced by Dow Chemical (DOW), with an octene monomer content of 35% to 40%; its melt index is 0.5 g / 10min (190°C, 2.16 kg);

[0047] Gallium metal, sourced from Gallium, with a purity of 99.99%;

[0048] Sodium dodecyl sulfate, sourced from Sinopharm Group, industrial grade;

[0049] 1-Ethyl-3-methylimidazolium tetrafluoroborate, sourced from Aladdin, purity >98%;

[0050] TAIC purity ≥99%, Japan Soda, brand TAIC 80, is used as a co-crosslinking agent to optimize the flexibility of the crosslinked network;

[0051] DCP is a Perkadox BCFF peroxide crosslinking agent produced by Arkema, with the brand name DCP6688;

[0052] The source of DOS plasticizer is Konings, Germany, with the brand name DOS 95;

[0053] The source of MAH-g-POE is LG Chem of South Korea, with the brand name MAH-g-POE 888;

[0054] The source of UV-326 is BASF, and the brand name is UV-326;

[0055] The source of rutile titanium dioxide is DuPont Chemical, with the brand name R960;

[0056] The source of antioxidant 1010 is BASF, and the brand is antioxidant 1010;

[0057] The source of antioxidant 1076 is BASF, and the brand is antioxidant 1076;

[0058] The source of Antioxidant 168 is BASF, and the brand is Antioxidant 168;

[0059] Nylon fiber mesh, sourced from Jiangsu Wujiang Zhengqing Textile Co., Ltd., with a yarn count of 480-520*450-470 per 10 cm (warp / weft), and a weight of 35 g / m². 2 , thickness is 90 um.

[0060] Examples 1-3

[0061] Example 1-3 provides a low-temperature resistant multi-layer insulation blanket for live working in cold areas, the structure of which is as follows: Figure 2-4 As shown, the raw materials for preparing the modified EVA film layer are shown in Table 1:

[0062] Table 1 Raw material formula of Examples 1-3

[0063]

[0064] The cold-resistant toughening resin is prepared according to the following method:

[0065] (1) Weigh 4 g of metallic gallium, 40 g of sodium dodecylsulfonate, 40 g of 1-ethyl-3-methylimidazolium tetrafluoroborate, and 1400 g of deionized water, add them into a 2 L glass beaker, and stir and mix them evenly with a glass rod; place the beaker in an ultrasonic emulsifier, set the ultrasonic power to 300 W, keep the temperature below 30 °C, and ultrasonicate for 20 minutes to obtain a uniform nano-dispersion liquid.

[0066] (2) Weigh 1000 g of POE8180 resin, 25 g of MAH-g-POE, and 2 g of antioxidant 1010, and put them into a high-speed mixer. Take 8 g of the nano-dispersion liquid in step (1) and slowly add it into the mixer. Stir at a low speed for 5 minutes and then switch to a high-speed stirring for 10 minutes to obtain a uniform premix.

[0067] (3) The premix is ​​put into an internal mixer, set the temperature to 130 °C, the speed to 40 rpm, and mixed for 15 minutes. After mixing, the material is taken out and spread on a cooling table to cool to room temperature. After cooling, it is cut into particles with a diameter of 3 to 5 mm using a pelletizer to obtain a cold-resistant toughened resin.

[0068] The preparation process of the above-mentioned low-temperature resistant multi-layer insulation blanket for live working in high-altitude cold areas is as shown in the attached figure. Figure 1 As shown, the specific preparation method is as follows:

[0069] (1) EVA resin, cold-resistant toughening resin and MAH-g-POE were put into a mixer and stirred at 55°C for 10 minutes until all components were fully mixed to obtain a premix.

[0070] (2) The premix was transferred to an internal mixer, and TAIC, DOS, DCP, titanium dioxide, UV326, antioxidant 1010, antioxidant 1076 and antioxidant 168 were added in sequence. The mixture was mixed at 120°C for 15 minutes to allow all the ingredients to react fully and disperse evenly to obtain a homogeneous rubber mix.

[0071] (3) The homogeneous mixed rubber is extruded through an extruder and calendered to form a modified EVA film with a thickness of 0.4 mm, which is then collected and cooled for later use.

[0072] (4) Take two layers of modified EVA film and one layer of nylon fiber mesh cloth, stack and flatten them in the order of "modified EVA film-nylon fiber mesh cloth-modified EVA film", put them into a hot pressing laminating machine, and hot press them at 140°C and a pressure of 8 MPa for 30 seconds to obtain a composite structure of modified EVA film / nylon fiber mesh cloth / modified EVA film, which are used as the upper insulating outer layer 7 and the lower insulating outer layer 9 of the insulation blanket respectively.

[0073] (5) Take 10 layers of modified EVA film and stack them as the middle insulating layer 8, stack the lower insulating outer layer 9, the middle insulating layer 8 and the upper insulating outer layer 7 in sequence and align them, use high-frequency welding equipment (frequency 27.12 MHz, output power 3 kW) to apply 0.6 MPa pressure on the four sides, the welding time is 2 seconds, ensure that each layer is fused and sealed into one, and obtain a semi-finished insulating blanket with a complete main structure.

[0074] (6) Velcro components are set at equal intervals around the welded edges, including hook-surface Velcro 1, 3, 5 and velvet-surface Velcro 2, 4, 6. The hook surface and velvet surface positions correspond to each other and are installed by hot pressing to complete the overall preparation of the low-temperature resistant multi-layer edge blanket for live working in high-altitude cold areas.

[0075] Comparative Example 1

[0076] This comparative example provides a low-temperature resistant multi-layer insulation blanket, which differs from Example 1 in that the cold-resistant toughening resin is replaced by POE resin.

[0077] Comparative Example 2

[0078] This comparative example provides a low-temperature resistant multi-layer insulation blanket, which differs from Example 1 in that it does not contain cold-resistant toughening resin and MAH-g-POE.

[0079] Performance Testing

[0080] The insulation blankets prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests according to the provisions of the DL / T803-2015 standard "Insulation Blankets for Live Working", and the results are shown in Table 2.

[0081] Table 2 Performance test results

[0082]

[0083] The above results show that the samples of Examples 1-3 significantly exceed the standard requirements in terms of mechanical properties such as tensile strength, elongation at break, tear strength, and puncture resistance. The materials as a whole exhibit high flexibility and excellent toughness enhancement. They also exhibit excellent electrical insulation and extreme low-temperature resistance, with no cracks at -40°C and no breakdown during the withstand voltage test, fully meeting the demanding working conditions required for live-line work in cold and high-altitude areas.

[0084] In Comparative Example 1, POE resin is used instead of the cold-resistant toughening resin of the present invention, and other proportions remain unchanged. The test results show that although the mechanical properties are slightly lower than those of the embodiment, they can still meet the standard requirements. Obvious cracks appear at a low temperature of -40°C, and the pressure test lasts only 13 seconds before breaking down. The adaptability to extremely cold environments is obviously insufficient, the brittleness of the material increases, and there are safety hazards. This shows that single POE toughening cannot fully achieve the synergistic improvement of mechanical and electrical properties under extremely cold working conditions.

[0085] Comparative Example 2, without the addition of cold-resistant toughening resin or compatibilizer, utilizes only conventional EVA-based materials. Test results show that while mechanical properties meet the standards, overall performance is significantly weaker than that of the examples. Numerous cracks appeared after mechanical impact at -40°C, and breakdown occurred after a pressure test lasting only 8 seconds, completely failing to meet the practical requirements of live-line work in cold and high-altitude regions. This sample fully demonstrates the inherent weakness of existing EVA insulation blankets, which are prone to brittleness and failure in extreme low-temperature environments.

[0086] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A low-temperature-resistant multi-layer insulation blanket for live-line work in cold and high-altitude areas, comprising an upper insulating outer layer, an intermediate insulating layer, and a lower insulating outer layer stacked in layers; the upper and lower insulating outer layers are each a composite structure comprising a nylon fiber mesh cloth and a modified EVA film laminated to both sides of the nylon fiber mesh cloth; the intermediate insulating layer is composed of multiple layers of modified EVA film stacked together; The raw materials for preparing the modified EVA film include, by mass percentage: EVA resin 70%~78%, cold-resistant toughening resin 15%~21%, cross-linking agent 0.6%~0.8%, plasticizer 1.5%~2.0%, vulcanizing agent 0.18%~0.22%, titanium dioxide 2.0%~3.0%, compatibilizer 1.5%~2%, UV absorber 0.5%~1%, composite antioxidant 0.30%~0.37%; The cold-resistant toughening resin is prepared according to the following steps: (1) Metal gallium is mixed with sodium dodecylsulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate and deionized water, and ultrasonication is applied to obtain a nano-dispersion liquid; (2) mixing POE resin, maleic anhydride grafted POE, antioxidant 1010 and the nano-dispersion obtained in step (1) to obtain a premix; (3) The premix is ​​put into an internal mixer and mixed at 120-140°C for 10-20 minutes. After discharging, the premix is ​​cooled and pelletized to obtain a cold-resistant toughened resin.

2. The low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to claim 1 is characterized by: The mass ratio of the metal gallium, sodium dodecylsulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate and deionized water in step (1) is 1: (8-12): (8-12): (300-400).

3. The low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to claim 1, characterized in that: In step (2), the mass ratio of the POE resin, maleic anhydride grafted POE (MAH-g-POE), antioxidant 1010, and nano-dispersion liquid is 100: (2-3): (0.15-0.25): (0.3-1).

4. The low-temperature resistant multi-layer insulation blanket for live working in cold regions according to claim 1, characterized in that: The crosslinking agent is triallyl isocyanurate, potassium persulfate, azobisisobutyronitrile, bismaleimide or pentaerythritol tetraacrylate; the vulcanizing agent is dicumyl peroxide, benzoyl peroxide, diisobutylbenzene peroxide or tert-butyl perbenzoate; the plasticizer is dioctyl sebacate, dioctyl phthalate, dibutyl phthalate, diisononyl phthalate or diisodecyl phthalate; the compatibilizer is maleic anhydride grafted POE; the ultraviolet absorber is UV326, UV-366, UV-327, UV-328, UV-329 or ultraviolet absorber TINUVIN1171.

5. The low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to claim 1, characterized in that: The composite antioxidant comprises antioxidant 1010, antioxidant 1076 and antioxidant 168, with a mass ratio of 1:(6-9):(9-15).

6. The low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to claim 1, characterized in that: The modified EVA film is prepared as follows: (1) Place EVA resin, cold-resistant toughening resin, and compatibilizer in a mixer and mix at 55±5°C for 5-15 minutes to obtain a premix; (2) Transfer the premix to an internal mixer, add a crosslinker, plasticizer, vulcanizer, titanium dioxide, UV absorber, and composite antioxidant, and mix at 120±10°C for 10-20 minutes to form a homogeneous rubber mix; (3) The mixed rubber is made into a modified EVA film through extrusion casting or calendering process.

7. The low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to any one of claims 1 to 6, characterized in that: The intermediate insulating layer is composed of 8 to 12 layers of modified EVA films stacked together.

8. The low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to any one of claims 1 to 6, characterized in that: The four sides of the upper insulating outer layer, the middle insulating layer and the lower insulating outer layer are sealed and fixed by high-frequency welding.

9. The method for preparing the low-temperature-resistant multi-layer insulation blanket for live working in cold regions according to any one of claims 1 to 6, comprising the following steps: (1) stacking two layers of modified EVA film and a layer of nylon fiber mesh cloth in the order of modified EVA film, nylon fiber mesh cloth, and modified EVA film, and performing hot pressing to obtain a modified EVA film / nylon fiber mesh cloth / modified EVA film composite structure as an upper insulating outer layer and a lower insulating outer layer; (2) Stack 8 to 12 layers of modified EVA film as the middle insulation layer, and align them in the order of lower insulation outer layer, middle insulation layer, and upper insulation outer layer. Use high-frequency welding equipment to pressurize and weld the four sides so that the materials at the edge are fused and sealed together; (3) Velcro components are arranged at equal intervals around the edge sealing, including hook-surface Velcro and velvet-surface Velcro, and the positions correspond to each other, thereby obtaining the low-temperature resistant multi-layer edge blanket for live-line working in high-altitude cold areas.

10. The preparation method according to claim 9, characterized in that: The welding pressure in step (2) is 0.4-0.8 MP, and the welding time is 1-4 seconds.

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