Low-temperature-resistant and ultraviolet-resistant multi-layer insulation blanket and preparation method thereof

Abstract

The present invention provides a low-temperature resistant and UV-resistant multi-layer insulation blanket and a preparation method thereof, and relates to the technical field of insulation materials for power equipment. The insulation blanket adopts a sandwich structure, and is formed by hot-pressing and compounding two layers of modified EVA film with a nylon fiber mesh cloth in the middle. By modifying the EVA resin with silicone intercalation, combined with POE, a cross-linking system and multiple anti-aging components, the material is made to have flexibility and high insulation properties at extremely low temperatures of ‑40°C, and can resist strong ultraviolet radiation for a long time, significantly improving mechanical strength, tear resistance and service life. Compared with traditional materials, the insulation blanket of the present invention has superior performance in high-cold and strong ultraviolet environments, providing a more reliable and safe insulation protection solution for live operations in distribution networks, and has a wide range of engineering applications and promotion value.

Description

Technical Field

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

[0002] With the continuous advancement of my country's distribution network construction, live-line operations are placing increasingly stringent demands on safety and protective materials, especially in high-altitude, cold regions and areas with strong ultraviolet radiation. The performance of insulating protective materials is directly related to the personal safety of workers. Currently, the most commonly used insulation blankets in China are primarily made of EVA resin. This material exhibits excellent flexibility and electrical insulation properties at room temperature, making it widely used for live-line operations on distribution lines of 10kV and above. However, traditional EVA insulation blankets are prone to performance degradation in low-temperature environments, especially below -20°C. The material itself gradually transitions from flexibility to brittleness, and the surface is prone to cracking and even brittle fracture. Impact resistance is severely reduced, and insulation capacity is also weakened. Furthermore, prolonged exposure to outdoor ultraviolet radiation can cause the EVA substrate to age and discolor, further reducing its mechanical strength and electrical insulation properties, impacting its long-term reliability.

[0003] In response to these problems, domestic scholars and companies have carried out a large number of technical improvements. For example, Chinese patent CN101722688A proposes a moisture-proof insulation blanket. Although it has certain flame retardant functions, it is still difficult to meet the requirements of use in extremely cold environments in terms of low-temperature resistance. CN103360635A discloses a multi-layer rubber composite insulation blanket. Although it claims to have certain high and low temperature resistance and buffering performance, the actual patent document lacks data support for low-temperature reliability. Moreover, because it mainly relies on rubber materials, it has a high density and insufficient tear resistance. During long-term use, it is easy to cause the insulation capacity to decline due to surface aging, and there are actual hidden dangers such as slipping and poor adhesion during high-altitude operations. In addition, the natural aging of rubber materials and the rapid decay of mechanical properties also make it difficult to ensure the service life and safety of rubber materials in complex working environments at high altitudes.

[0004] Summarizing existing technologies, it is known that the insulation blanket products currently on the market cannot simultaneously take into account mechanical flexibility in extremely cold and low temperatures, anti-aging capabilities in strong UV environments, and high electrical insulation performance during long-term service. Especially in extremely low temperature scenarios such as -40°C, most materials face technical bottlenecks such as low-temperature embrittlement, insulation failure, and surface cracking. Therefore, in extremely cold and strong UV areas, live operations on power systems place more stringent performance requirements on insulation blanket materials. There is an urgent need to develop a new type of insulation blanket material that can withstand extremely low temperatures and high UV intensities for a long time, while also possessing excellent mechanical strength and electrical insulation properties, in order to ensure the personal safety of workers in extreme environments and the operational reliability of power systems. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a low-temperature-resistant and UV-resistant multi-layer insulation blanket and a preparation method thereof. The insulation blanket of the present invention remains flexible and insulating at a low temperature of -40°C and is not prone to aging and failure due to long-term exposure to sunlight, providing a safer and more reliable insulation protection solution for power operations in high-altitude and cold areas with strong UV rays.

[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 an EVA film layer for a low-temperature-resistant and ultraviolet-resistant multi-layer insulation blanket. The raw materials for preparing the EVA film layer include, by mass percentage, 84% to 87% of a modified EVA resin, 5% to 7% of a POE resin, 0.6% to 0.8% of a crosslinking agent, 0.18% to 0.22% of a vulcanizing agent, 1.5% to 2.0% of a plasticizer, 1.5% to 2.0% of a compatibilizer, 0.5% to 1% of a UV absorber, 0.3% to 0.5% of a light stabilizer, 2.0% to 3.0% of titanium dioxide, 0.2% to 0.3% of a silane coupling agent, and 0.34% to 0.6% of a composite antioxidant.

[0008] Furthermore, the modified EVA resin is prepared according to the following method:

[0009] (1) Dihydroxy polydimethylsiloxane (PDMS) and polyethylene glycol diacrylate (PEGDA) are mixed, p-toluenesulfonic acid is added as a catalyst, and the mixture is reacted at 100-140°C for 4-7 hours to obtain an organosilicon intercalant;

[0010] (2) EVA resin, the organosilicon intercalant obtained in step (1), hexanediol diborate, and boron trifluoride-ether complex are put into an internal mixer and mixed at 120-130° C. for 15-30 minutes to obtain an organosilicon intercalation modified EVA blend;

[0011] (3) The silicone intercalation modified EVA blend is extruded through a twin-screw extruder and granulated to obtain a modified EVA resin. The obtained modified EVA resin is vacuum dried and set aside.

[0012] Furthermore, in step (1), the mass ratio of dihydroxy polydimethylsiloxane (PDMS) to polyethylene glycol diacrylate (PEGDA) is 3.0:1 to 5.5:1; and the amount of p-toluenesulfonic acid added is 0.4-0.6% of the total mass of dihydroxy polydimethylsiloxane (PDMS) and polyethylene glycol diacrylate (PEGDA).

[0013] Furthermore, in step (2), the mass of the organosilicon intercalant is 2-5% of the EVA resin, the mass of hexanediol diborate is 0.2-0.5% of the EVA resin, and the mass of the boron trifluoride-ether complex is 0.02-0.05% of the EVA resin.

[0014] Traditional EVA resin has long been the mainstream base resin for insulating materials due to its excellent flexibility, electrical insulation, and processing properties. It imparts excellent mechanical compliance and reliable safety isolation to insulating blankets. However, the EVA molecular backbone, a non-polar copolymer of ethylene and vinyl acetate, is susceptible to chain segment freezing and material embrittlement at low temperatures. Its impact resistance and electrical insulation stability also present certain bottlenecks under extreme operating conditions. Furthermore, it is susceptible to degradation and aging after long-term service under high-energy UV irradiation. Therefore, the present invention utilizes molecular-level organosilicon intercalation in conjunction with a dynamic covalent network to target and modify EVA resin, achieving a systematic improvement in the material's fundamental properties. In this invention, polydimethylsiloxane (PDMS) with hydroxyl groups at both ends is esterified with polyethylene glycol diacrylate (PEGDA) containing acrylate-reactive groups at both ends to form an organosilicon intercalant with a flexible Si-O-Si backbone. The flexible long chains of PDMS undergo acid-catalyzed esterification with the terminal acrylates of PEGDA, giving the intercalant both a highly flexible backbone and active end groups capable of participating in the blending reaction. During the subsequent mixing and blending process, the acrylate groups of the intercalant undergo a dynamic covalent intercalation reaction with the EVA molecular segments, catalyzed by hexanediol diborate and a boron trifluoride-ether complex. The acrylate end groups form dynamic borate bonds with the hexanediol diborate, while the boron trifluoride-ether complex enhances the interaction between the intercalant end groups and alcohol or carboxyl impurities on the EVA chain. This reaction forms a subnanometer-scale dynamic cross-linked network between molecules, uniformly distributing the PDMS segments through intercalation between the EVA backbone chains, significantly enhancing the system's segmental flexibility and low-temperature toughness. Due to its high flexibility and chemical inertness, the intercalated silicone segment can prevent the vitrification and freezing of the EVA segment in extreme low-temperature environments, giving the material excellent softness and impact resistance. At the same time, the Si-O main chain structure greatly improves the electrical insulation strength, heat resistance, and aging resistance of the overall system. As part of the intercalant molecule, the PEGDA unit enhances polar synergy and interfacial compatibility with the EVA matrix, effectively avoiding the phase separation and uneven dispersion problems that are common in conventional inorganic fillers or blends. Hexanediol diborate acts as a dynamically reversible crosslinking regulator, making the bond between the intercalant and EVA segment both tough and reversible, ensuring mechanical strength while giving the system greater microstructural stability. Overall, after the modified EVA resin is introduced into the insulation blanket formula as the main matrix, it works highly synergistically with the POE cold-resistant components, compatibilizers, light stabilizers, UV absorbers and other additives in the system, further improving the long-term service performance of the composite material in extremely low temperatures and strong UV environments, making the insulation blanket achieve performance levels far higher than traditional EVA matrices in key indicators such as mechanical flexibility, insulation capacity and weather resistance.

[0015] Further, 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 light stabilizer is HALS 944, HALS 1077, Tinuvin 770DF or Tinuvin 622LF;

[0021] Furthermore, the silane coupling agent is KH-550, KH-560, KH-570, KH-580 or A-174.

[0022] Furthermore, the composite antioxidant includes antioxidant 1010, antioxidant 1076 and antioxidant 168 in a mass ratio of 1:(4-9):(10-15).

[0023] In the EVA film layer formulation of the insulating blanket material of this invention, in addition to structural optimization of the EVA main matrix through molecular-level organosilicon intercalation and dynamic covalent networking, the collaborative design of the various functional components in the formula also plays a key role in improving the overall performance of the material. The cross-linked network is regulated by compounding triallyl isocyanurate (TAIC) and dicumyl peroxide (DCP). By precisely controlling the cross-linker ratio and cross-linking reaction conditions, the cross-linking degree is stabilized at 80-85%. This effectively optimizes the spatial structure of the polymer network, enhances the overall toughness and dimensional stability of the material, and avoids the risk of embrittlement caused by excessive cross-linking. The anti-aging system achieves efficient shielding against high-energy UV rays and the capture and inhibition of free radicals through the triple synergistic protection of UV absorber UV326, hindered amine light stabilizer HALS944, and rutile titanium dioxide. Specifically, UV326 absorbs ultraviolet light in the 280-400 nm range, preventing photofragmentation and degradation of polymer chains. HALS944 effectively inhibits photooxidative chain reactions by capturing and eliminating free radicals generated by UV irradiation. Rutile titanium dioxide, with its excellent light-shielding and light-reflecting properties, builds a dense inorganic protective barrier on the material surface, enhancing overall weather resistance while further delaying the photoaging of organic components. Regarding plasticization and compatibility, the formulation utilizes the migration-resistant dioctyl sebacate (DOS) as a plasticizer. This lowers the glass transition temperature of the polymer, further enhancing the system's low-temperature flexibility and preventing loss of the plasticizing effect during long-term service. Furthermore, maleic anhydride-grafted POE (MAH-g-POE) is used as a compatibilizer to effectively improve interfacial compatibility between multiphase systems, such as EVA and POE, inhibiting phase separation and component migration, and ensuring the long-term stability of the composite's mechanical and insulating properties. The precise synergy between the various components not only enhances the material's mechanical, electrical, and weathering performance in extreme environments, but also fully unleashes the potential of the silicone-intercalated EVA matrix, enabling the insulation blanket to achieve overall performance levels far exceeding those of traditional materials under harsh operating conditions such as high cold and strong UV exposure. The composite antioxidant system comprises antioxidant 1010, antioxidant 1076, and antioxidant 168. Antioxidant 1010, a main-chain phenolic antioxidant, effectively captures free radicals induced by heat and light during material formation and initial service life, preventing polymer chain breakage and degradation. Antioxidant 1076, a hindered phenolic antioxidant, complements 1010, enhancing overall free radical scavenging efficiency and delaying the material's performance degradation caused by thermal oxidation during long-term use. Antioxidant 168 primarily decomposes peroxide intermediates produced during polymer thermal processing, improving the material's heat aging resistance and synergistically enhancing its processing stability.

[0024] A second aspect of the present invention provides a method for preparing the EVA film layer for the above-mentioned low-temperature-resistant and UV-resistant multi-layer insulation blanket, comprising the following steps:

[0025] (1) Mixing modified EVA resin, POE resin, crosslinking agent, vulcanizing agent, plasticizer, and compatibilizer to obtain a premix;

[0026] (2) Transfer the premix to an internal mixer, add the ultraviolet absorber, light stabilizer, titanium dioxide, silane coupling agent and composite antioxidant in sequence, and mix at 125±5℃ for 5-15 minutes to form a homogeneous rubber mix;

[0027] (3) Extruding the homogeneous mixed rubber into granules, and rolling the obtained granules into films to obtain EVA films;

[0028] (4) The EVA film is subjected to heat treatment and cross-linking to obtain the EVA film layer.

[0029] Furthermore, the thickness of the EVA film in step (3) is 0.12±0.02 mm.

[0030] Furthermore, the heat treatment temperature in step (4) is 110-120° C., the time is 10-30 minutes, and the cross-linking degree is 80-85%.

[0031] The third aspect of the present invention provides a low-temperature resistant and UV-resistant multi-layer insulation blanket, whose structure includes an EVA film layer, a base fabric layer and an EVA film layer arranged in sequence. The base fabric layer is a nylon fiber mesh cloth, which is located between two EVA film layers to form a sandwich composite structure as a whole.

[0032] A fourth aspect of the present invention provides a method for preparing a low-temperature resistant and UV-resistant multi-layer insulation blanket, comprising hot-pressing and laminating upper and lower EVA film layers with a nylon fiber mesh cloth, and cooling the blanket to obtain the blanket.

[0033] Furthermore, the hot pressing composite is performed at a temperature of 135-145° C., a pressure of 7-9 MPa, and a time of 20-40 seconds.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention significantly improves the comprehensive performance of the insulation blanket in extremely low temperature and strong ultraviolet light environments through innovative modification of the molecular structure of the EVA resin, and the scientific combination of POE, a cross-linking system, and multiple anti-aging components. Performance tests have shown that the insulation blanket of the present invention remains flexible and highly insulating at -40°C, and its key indicators such as mechanical strength, tear resistance, and puncture resistance are superior to those of traditional materials. Under artificially accelerated ultraviolet aging conditions, the mechanical properties are highly retained, with no obvious cracking or discoloration on the surface, and the long-term service reliability is outstanding. The material structure is stable and the preparation process is controllable, providing a safer, more durable, and more environmentally friendly insulation protection solution for live operations in distribution networks in high-altitude and strong ultraviolet regions, and has broad engineering application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart for preparing a low-temperature-resistant and UV-resistant multi-layer insulation blanket.

[0037] Figure 2 This is a schematic diagram of the overall structure of a low-temperature-resistant and UV-resistant multi-layer insulation blanket of the present invention.

[0038] Figure 3 This is a schematic side view of the structure of a low-temperature-resistant and UV-resistant multi-layer insulation blanket according to the present invention.

[0039] Reference numerals: EVA film layer 1, nylon base fabric layer 2, EVA film layer 3. DETAILED DESCRIPTION

[0040] 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.

[0041] The following raw material sources are illustrative:

[0042] 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 ;

[0043] Dihydroxy polydimethylsiloxane, sourced from Shenzhen Jipeng Silicone Fluoride Materials Co., Ltd., has a hydroxyl content of 9% and a viscosity range of 5~50 mm² / S (25°C).

[0044] Polyethylene glycol diacrylate, sourced from Yixing Wencheng Chemical Co., Ltd., viscosity 80~120 (25°C), color number <100, acid value <0.5 mg KOH / g.

[0045] Hexanediol diborate, source: Alfa Chemistry.

[0046] Boron trifluoride-diethyl ether complex, source: Shandong Wanbang Chemical Industry Co., Ltd.

[0047] 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);

[0048] TAIC purity ≥99%, Japan Soda, brand TAIC 80, is used as a co-crosslinking agent to optimize the flexibility of the crosslinked network;

[0049] DCP is a Perkadox BCFF peroxide crosslinking agent produced by Arkema, with the brand name DCP6688;

[0050] The DOS plasticizer is sourced from Corning, Germany, with the brand name DOS 95; MAH-g-POE is sourced from LG Chem, South Korea, with the brand name MAH-g-POE 888; UV-326 is sourced from BASF, with the brand name UV-326; HALS 944 is sourced from Ciba Specialty Chemicals, with the brand name HALS 944; rutile titanium dioxide is sourced from DuPont Chemical, with the brand name R960; silane coupling agent is sourced from Shandong Nabaichuan, with the brand name KH-550; antioxidant 1010 is sourced from BASF, with the brand name Antioxidant 1010; antioxidant 1076 is sourced from BASF, with the brand name Antioxidant 1076; antioxidant 168 is sourced from BASF, with the brand name Antioxidant 168;

[0051] 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.

[0052] Examples 1-3

[0053] Embodiment 1-3 provides a low temperature resistant and UV resistant multilayer insulation blanket, the structure of the low temperature resistant and UV resistant multilayer insulation blanket is as follows Figure 2 and Figure 3 The raw materials for preparing the EVA film layer are shown in Table 1:

[0054] Table 1 Raw material formula of Examples 1-3

[0055]

[0056] The modified EVA resin is prepared as follows:

[0057] (1) Take dihydroxy polydimethylsiloxane with a molecular weight of about 2000 and polyethylene glycol diacrylate in a mass ratio of 3.5:1, and add the two into a four-necked flask equipped with a mechanical stirrer, a thermometer, a reflux condenser and a nitrogen protection interface; add 0.5% of the total mass of p-toluenesulfonic acid as a catalyst, heat to 120℃ under nitrogen atmosphere, start mechanical stirring (speed 300 rpm), and react at a constant temperature for 6 hours. After the reaction is completed, cool the system to room temperature, and remove trace volatiles by vacuum rotary evaporation to obtain an organosilicon intercalant.

[0058] (2) Take EVA resin, silicone intercalant (3% of EVA mass), hexanediol diborate (0.3% of EVA mass), and boron trifluoride-ether complex (0.03% of EVA mass), mix all the components evenly, and put them into an internal mixer. Set the internal mixer temperature to 125 ° C, the speed to 60 rpm, and the internal mixer time to 20 minutes. During the internal mixer, nitrogen protection is continuously applied to prevent oxidative decomposition. After the internal mixer is completed, take out the micelles and cool them to room temperature to obtain silicone intercalation modified EVA blends.

[0059] (3) The above-mentioned silicone intercalated modified EVA blend was put into a twin-screw extruder, and the temperature of each temperature zone was set to 120°C, 130°C, 135°C, 130°C, and 125°C, the head temperature was 130°C, and the screw speed was 180 rpm. The extrusion was granulated to obtain modified EVA resin particles, and the obtained particles were placed in a vacuum oven at 60°C and dried for 8 hours for use.

[0060] The preparation process of the above-mentioned low temperature resistant and UV resistant multilayer insulation blanket is as shown in the attached figure. Figure 1 As shown, the specific preparation method is as follows:

[0061] (1) The modified EVA resin was dried in a vacuum drying oven at 60°C for 10 hours, and the POE8180 was dried in a vacuum drying oven at 70°C for 8 hours. The nylon fiber base fabric was corona treated with a treatment intensity of 4045 dyne / cm² to increase its surface energy. The base fabric surface was evenly coated with a 0.51 g / m² polyurethane primer to enhance the bonding strength between the EVA and nylon. The dried modified EVA, POE8180, TAIC, DCP, DOS, and MAH-g-POE were placed in a high-speed mixer and mixed at 55±5°C for 8 minutes to ensure that the raw materials were evenly dispersed to obtain a premix.

[0062] (2) Transfer the premix to an internal mixer, add UV absorber UV326, light stabilizer HALS 944, rutile titanium dioxide, silane coupling agent and composite antioxidant in sequence, and mix at 125±5℃ for 10 minutes to form a homogeneous rubber mixture.

[0063] (3) The rubber mixture was fed into a twin-screw extruder (length-to-diameter ratio 40:1), and the temperatures of each zone were set to 120°C, 130°C, 140°C, 135°C, and 130°C in sequence. The die temperature was 130°C, the screw speed was 200 r / min, and the pellets were extruded and cut into pellets to obtain pellets. The pellets were fed into a three-roll calender (roller diameter Φ600 mm), the upper roll temperature was 80°C, the middle roll temperature was 85°C, and the lower roll temperature was 80°C. The line speed was 2.5 m / min, and the EVA film with a thickness of about 0.12 mm was calendered.

[0064] (4) The EVA film is heat-treated and cross-linked at a temperature of 115°C, a cross-linking time of 20 minutes, and a cross-linking degree of about 83%, to obtain EVA film layers 1 and 3.

[0065] (5) The upper and lower EVA film layers 1 and 3 are hot-pressed with the nylon fiber base fabric 2 at 140°C and a pressure of 8 MPa, and the holding time is 30 seconds.

[0066] (6) A gradient cooling process was used to first air-cool the composite material to 50°C and then water-cool it to 30°C. The tension was controlled at 80 N during winding and the tool speed was 800 r / min during slitting. Finally, a low-temperature and UV-resistant multi-layer insulation blanket was obtained.

[0067] Comparative Example 1

[0068] This comparative example provides a low-temperature-resistant and UV-resistant multi-layer insulation blanket, which is different from Example 1 in that it does not contain POE8180 and MAH-g-POE, and is the same as Example 1 in other respects.

[0069] Comparative Example 2

[0070] This comparative example provides a low-temperature-resistant and UV-resistant multi-layer insulation blanket, which differs from Example 1 in that the modified EVA resin is replaced by unmodified EVA resin.

[0071] Performance Testing

[0072] 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.

[0073] Table 2 Performance test results

[0074]

[0075] The insulation blankets prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their anti-ultraviolet aging performance. The test was conducted with reference to GB / T16422.2-2014 "Plastics Laboratory Light Source Exposure Test Methods Part 2: Xenon Arc Lamp". After 500 hours of irradiation in a xenon arc lamp aging test chamber, the changes in tensile strength and elongation at break were detected. The irradiation spectrum range was 290-400 nm, and the irradiation intensity was 0.51 W / (m 2 ·nm) (at 340 nm), the blackboard temperature was maintained at (63±3)℃, and the cycle was set to 102 minutes of light exposure + 18 minutes of water spray cooling, continuous cycle, for a total exposure of 500 hours.

[0076] The test results are shown in Table 3.

[0077] Table 3 Performance test results

[0078]

[0079] These results demonstrate that by optimizing the matrix material, cross-linking network, and anti-aging system, the invention significantly improves the mechanical properties, low-temperature toughness, UV resistance, and insulation performance of the insulation blanket. Examples 1-3 maintain high insulation performance at -40°C, fully meeting the stringent requirements of 10kV distribution lines in cold and high-altitude regions.

[0080] Comparative Example 1, which lacks POE and a compatibilizer, exhibits some acceptable performance, but exhibits significantly insufficient low-temperature embrittlement resistance and insulation stability, with a significant drop in breakdown voltage at low temperatures. This suggests that the regulation of cold resistance and interfacial compatibility in the formulation significantly impacts overall performance. Comparative Example 2, which does not utilize modified EVA resin, exhibits significant degradation in material performance after aging, with UV resistance and mechanical retention significantly lower than those of the examples, demonstrating the synergistic innovation and superiority of the present material system.

[0081] 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 and UV-resistant multi-layer insulation blanket, comprising an EVA film layer, a base fabric layer, and an EVA film layer arranged in sequence. The base fabric layer is a nylon fiber mesh cloth located between two EVA film layers, forming a sandwich composite structure. The raw materials for preparing the EVA film layer include, by mass percentage: Modified EVA resin 84%~87%, POE resin 5%~7%, crosslinking agent 0.6%~0.8%, vulcanizing agent 0.18%~0.22%, plasticizer 1.5%~2.0%, compatibilizer 1.5%~2.0%, UV absorber 0.5%~1%, light stabilizer 0.3%~0.5%, titanium dioxide 2.0%~3.0%, silane coupling agent 0.2%~0.3%, composite antioxidant 0.34%~0.6%; The modified EVA resin is prepared as follows: (1) Dihydroxy polydimethylsiloxane and polyethylene glycol diacrylate are mixed, p-toluenesulfonic acid is added as a catalyst, and the mixture is reacted at 100-140°C for 4-7 hours to obtain an organosilicon intercalant; (2) EVA resin, the organosilicon intercalant obtained in step (1), hexanediol diborate, and boron trifluoride-ether complex are put into an internal mixer and mixed at 120-130° C. for 15-30 minutes to obtain an organosilicon intercalation modified EVA blend; (3) The silicone intercalated modified EVA blend is extruded through a twin-screw extruder and granulated to obtain a modified EVA resin.

2. The low-temperature-resistant and UV-resistant multi-layer insulation blanket according to claim 1, characterized in that: In step (1), the mass ratio of dihydroxy polydimethylsiloxane to polyethylene glycol diacrylate is 3.0:1 to 5.5:1; and the amount of p-toluenesulfonic acid added is 0.4-0.6% of the total mass of dihydroxy polydimethylsiloxane and polyethylene glycol diacrylate.

3. The low-temperature-resistant and UV-resistant multi-layer insulation blanket according to claim 1, characterized in that: In step (2), the mass of the organosilicon intercalant is 2-5% of the EVA resin, the mass of hexanediol diborate is 0.2-0.5% of the EVA resin, and the mass of the boron trifluoride-ether complex is 0.02-0.05% of the EVA resin.

4. The low-temperature-resistant and UV-resistant multi-layer insulation blanket 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 (MAH-g-POE); the ultraviolet absorber is UV326, UV-366, UV-327, UV-328, UV-329 or ultraviolet absorber TINUVIN1171; the light stabilizer is HALS944, HALS 1077, Tinuvin770DF or Tinuvin622LF; the silane coupling agent is KH-550, KH-560, KH-570, KH-580 or A-174.

5. The low-temperature-resistant and UV-resistant multi-layer insulation blanket according to claim 1, characterized in that: The composite antioxidant comprises antioxidant 1010, antioxidant 1076 and antioxidant 168, with a mass ratio of 1:(4-9):(10-15).

6. The low-temperature-resistant and UV-resistant multi-layer insulation blanket according to any one of claims 1 to 5, characterized in that: The EVA film layer is prepared as follows: (1) Mixing modified EVA resin, POE resin, crosslinking agent, vulcanizing agent, plasticizer, and compatibilizer to obtain a premix; (2) Transfer the premix to an internal mixer, add the ultraviolet absorber, light stabilizer, titanium dioxide, silane coupling agent and composite antioxidant in sequence, and mix at 125±5℃ for 5-15 minutes to form a homogeneous rubber mix; (3) Extruding the homogeneous mixed rubber into granules, and rolling the obtained granules into films to obtain EVA films; (4) The EVA film is subjected to heat treatment and cross-linking to obtain the EVA film layer.

7. The low-temperature-resistant and UV-resistant multi-layer insulation blanket according to claim 6, characterized in that: The thickness of the EVA film in step (3) is 0.12±0.02 mm.

8. The low-temperature-resistant and UV-resistant multi-layer insulation blanket according to claim 6, characterized in that: The heat treatment temperature in step (4) is 110-120°C, the time is 10-30 minutes, and the cross-linking degree is 80-85%.

9. A method for preparing the low-temperature-resistant and ultraviolet-resistant multi-layer insulation blanket according to any one of claims 1 to 8, comprising hot-pressing and laminating the upper and lower EVA film layers with the nylon fiber mesh cloth, and cooling the laminate.

10. The preparation method according to claim 9, characterized in that: The hot pressing compounding is performed at a temperature of 135-145° C., a pressure of 7-9 MPa, and a time of 20-40 seconds.

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