High-voltage-resistant high-tack natural rubber terminated adhesive tape, preparation method and application thereof

Abstract

The application discloses a high-voltage-resistant high-tackiness natural rubber termination adhesive tape, a preparation method and application thereof, and relates to the field of lithium ion battery termination adhesive tapes.The termination adhesive tape comprises a substrate layer and an adhesive layer, and the adhesive layer comprises the following components: natural rubber, liquid polyisoprene, tackifying resin, nano-composite ceramic dielectric filler, silane coupling agent, phenolic resin vulcanizing agent, active agent / acid acceptor, and other auxiliary agents.The application constructs a high-temperature stable crosslinking network through natural rubber and phenolic resin vulcanizing agent, uniformly distributes electric field through nano-composite ceramic dielectric filler to improve breakdown strength, and enhances the combination of filler-rubber interface through silane coupling agent to inhibit corona discharge.The ratio of the peeling force of the adhesive tape after soaking in electrolyte at 85 DEG C for 24 hours to the peeling force before soaking is greater than 80%, and the voltage resistance of a single battery can reach 4.5 volts.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery termination tapes, and in particular to a high-voltage resistant, high-viscosity natural rubber termination tape, its preparation method, and its application. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the energy density and voltage platform of power batteries are constantly improving. While 800V high-voltage power batteries bring higher charging efficiency and power density, they also pose unprecedented challenges to the internal insulation materials. The electrolyte inside the battery typically consists of organic carbonate solvents (such as dimethyl carbonate (DMC) and ethylene carbonate (EC)) and lithium salts (such as lithium hexafluorophosphate). It is composed of ( ) and has strong corrosive properties.

[0003] Traditional termination tapes mostly use acrylic pressure-sensitive adhesive as the adhesive layer. Although acrylic pressure-sensitive adhesive has excellent transparency, weather resistance, and initial tack, its molecular structure contains a large number of polar groups such as ester and carboxyl groups. In the high temperature, high humidity, and highly polar electrolyte environment inside a power battery, these groups are prone to hydrolysis, swelling, and even chemical reactions, leading to damage to the adhesive layer structure, a sharp decrease in adhesion, and even problems such as detachment and cracking. This can cause short circuits between electrodes or between electrodes and the casing, resulting in serious safety accidents.

[0004] To address the chemical resistance issues of acrylic pressure-sensitive adhesives (PSAs), researchers have turned to rubber-based PSAs. However, traditional rubber-based PSAs also have inherent contradictions. On the one hand, to achieve high initial tack, large amounts of low-molecular-weight tackifying resins and plasticizers are typically added, which reduces the cohesive strength and glass transition temperature of the adhesive layer, causing it to soften, creep, and even flow at high temperatures. On the other hand, to improve high-temperature stability, the crosslinking density needs to be increased, but this makes the adhesive layer harder and more brittle, reducing initial tack and conformability. This contradiction between initial tack and high-temperature stability is a major challenge in the design of rubber-based PSAs.

[0005] Furthermore, while nano-ceramic fillers are an effective means to improve insulation performance, their application also faces significant technical challenges. Nanoparticles, due to their extremely high specific surface area and surface energy, are highly prone to agglomeration. If uniform single-particle dispersion cannot be achieved within the polymer matrix, the agglomerated filler not only fails to provide a uniform electric field but also becomes stress concentration points and electrical weaknesses, leading to partial discharge and breakdown, ultimately resulting in material performance degradation.

[0006] Therefore, developing a novel termination tape that is chemically stable, resistant to high temperatures and electrolyte corrosion, and has excellent adhesion to internal battery components has become a pressing technical problem to be solved in this field. Summary of the Invention

[0007] This invention aims to overcome the aforementioned deficiencies of existing termination tape technologies and provides a high-voltage-resistant, high-viscosity natural rubber termination tape, its preparation method, and its applications. The technical problems to be solved by this invention include: how to fundamentally avoid the performance degradation problem caused by the degradation of acrylic pressure-sensitive adhesive in the electrolyte; how to achieve a balance between high initial tack and high-temperature stability to prevent high-temperature creep; how to improve the breakdown strength and long-term electrical insulation reliability of the termination tape; and how to achieve uniform dispersion and strong interfacial bonding of nano-ceramic fillers in the rubber matrix.

[0008] To address the aforementioned technical problems, this invention proposes a high-voltage-resistant, high-viscosity natural rubber termination tape, comprising a substrate layer and an adhesive layer coated on at least one side of the substrate layer. The adhesive layer, by weight percentage, comprises the following components: 30-45% natural rubber, 8-15% liquid polyisoprene, 15-25% tackifying resin, 5-12% nano-composite ceramic dielectric filler, 0.5-2% silane coupling agent, 3-8% phenolic resin vulcanizing agent, 1-3% activator / acid acceptor, and the balance being other additives.

[0009] The phenolic resin vulcanizing agent is used to form a CC crosslinking network with natural rubber; the nanocomposite ceramic dielectric filler is used to uniformly distribute the electric field and improve the breakdown strength; the silane coupling agent is used to enhance the interfacial bonding between the nanocomposite ceramic dielectric filler and natural rubber.

[0010] Preferably, the natural rubber is smoked sheet rubber or standard rubber, and the Mooney viscosity ML(1+4) at 100°C is 60~90.

[0011] Preferably, the liquid polyisoprene has a number-average molecular weight of 10,000 to 50,000 and a cis-1,4 structure content of more than 90%.

[0012] Preferably, the tackifying resin is at least one of rosin resin, terpene resin, or C5 / C9 petroleum resin.

[0013] Preferably, the nanocomposite ceramic dielectric filler is composed of at least two of alumina, silicon dioxide, boron nitride, or barium titanate, with an average particle size of 20-100 nm.

[0014] Preferably, the phenolic resin vulcanizing agent is a linear phenolic resin or a thermosetting phenolic resin, and the hydroxyl equivalent is 100~200g / eq.

[0015] Preferably, the activator / acid acceptor is at least one of zinc oxide, stearic acid, or magnesium oxide.

[0016] Preferably, the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or vinyltriethoxysilane.

[0017] Preferably, the substrate layer is a polyethylene terephthalate film or a polyimide film with a thickness of 25~100μm.

[0018] On the other hand, this invention proposes a method for preparing a high-voltage resistant, high-viscosity natural rubber termination tape, comprising the following steps: S1: Weigh each component raw material according to the formula ratio, and plasticize natural rubber and liquid polyisoprene in an internal mixer at 80~120℃ for 5~15 minutes; S2: Add tackifying resin, nano-composite ceramic dielectric filler, silane coupling agent, phenolic resin vulcanizing agent, activator / acid acceptor and other additives to the plasticized rubber obtained in step S1, and mix at 80~120℃ for 15~30 minutes to obtain the compounded rubber. The mixing temperature is 100℃ and the mixing time is 20 minutes; S3: Dissolve the compound obtained in step S2 in an organic solvent to prepare a rubber solution with a solid content of 20-40%. S4: Apply the adhesive obtained in step S3 evenly to the surface of the substrate layer using a precision coating method. The coating speed is 5~20m / min and the coating thickness is 15~50μm. S5: The substrate coated with adhesive layer obtained in step S4 is sent into a hot air circulating oven for drying and heat curing treatment. The curing temperature is 120~180℃ and the curing time is 5~15 minutes. The thermosetting process adopts a segmented curing method, first pre-curing at 120~140℃ for 3~5 minutes, and then main curing at 160~180℃ for 5~10 minutes; S6: The cured termination tape from step S5 is cooled to room temperature using a cooling roller and then wound up under constant tension to obtain the termination tape.

[0019] The beneficial effects of this application are: 1. This invention uses natural rubber as a highly elastic matrix. Natural rubber is renowned for its excellent elasticity and mechanical strength. Its molecular chain contains a large number of cis-1,4-polyisoprene structures, which endow the material with excellent resilience and flexibility. In tape applications, natural rubber constitutes a highly elastic viscoelastic matrix, which not only provides basic cohesive force, ensuring that the tape is not easily broken under stress, but also gives the tape good conformability, allowing it to adhere tightly to various irregular surfaces.

[0020] 2. Under high temperature or the action of a specific catalyst, the hydroxymethyl groups in the phenolic resin of this invention can react with the unsaturated bonds on the natural rubber molecular chain to form stable CC crosslinks. Compared with the traditional sulfur vulcanization system, the crosslinked network formed by this phenolic resin vulcanization has higher thermal and chemical stability, and can maintain its structural integrity for a long time under high temperature conditions, thereby giving the tape excellent high-temperature resistance.

[0021] 3. The nano-ceramic fillers of this invention, such as alumina, silicon dioxide, boron nitride, or barium titanate, possess extremely high dielectric strength and excellent chemical stability. When these nanoparticles are uniformly dispersed in a rubber matrix, they can effectively homogenize the electric field distribution and reduce local electric field concentration, thereby significantly improving the overall breakdown strength of the material. Furthermore, the high specific surface area of ​​the nanoparticles can introduce a large number of filler-rubber interfaces, which can trap charge carriers, suppress the growth of electrical trees, and further enhance insulation performance.

[0022] 4. This invention solves the problems of dispersion and interfacial bonding of nanofillers by applying silane coupling agents. Silane coupling agents act as molecular bridges connecting inorganic fillers and organic polymer matrices. By using silane coupling agents, covalent bonds can be formed between nanoceramic fillers and natural rubber. This strong chemical bonding greatly enhances the interfacial bonding force, ensuring the uniform dispersion and long-term stability of the filler in the matrix. More importantly, this chemically bonded interface can effectively transfer stress and suppress interfacial polarization and charge accumulation caused by differences in dielectric constants, thereby significantly reducing the risk of interfacial discharge.

[0023] In a preferred embodiment, the high-voltage resistant, high-viscosity natural rubber termination tape of the present invention, after being soaked in electrolyte at 85°C for 24 hours, exhibits a peel force ratio greater than 80% of the peel force before soaking, and the withstand voltage inside a single battery can reach 4.5 volts. Attached Figure Description

[0024] Figure 1 This is a photograph of the high-voltage resistant, high-viscosity natural rubber termination tape prepared in Example 1 of this application. Detailed Implementation

[0025] Example 1 A high-voltage resistant, high-viscosity natural rubber termination tape includes a substrate layer and an adhesive layer coated on at least one side of the substrate layer.

[0026] The adhesive layer comprises, by weight percentage, the following components: 38% natural rubber, 12% liquid polyisoprene, 20% tackifying resin, 8% nanocomposite ceramic dielectric filler, 1.2% silane coupling agent, 5% phenolic resin vulcanizing agent, 2% activator / acid acceptor, and the balance of other additives.

[0027] The natural rubber used is STR20 standard rubber (Mounney viscosity ML(1+4) 75 at 100°C) produced by Thai Shitong Rubber Co., Ltd. This rubber has excellent elasticity and mechanical strength, providing basic cohesion and flexibility for the adhesive layer.

[0028] The liquid polyisoprene used is LIR-50 liquid isoprene rubber (number average molecular weight 28,000, cis-1,4 structure content 92%) manufactured by Kuraray Corporation of Japan, as an internal plasticizer to improve viscosity and flexibility at low temperatures.

[0029] The tackifying resin used is Piccolyte S115 terpene resin manufactured by Eastman Chemical Company, USA, which provides initial fast tack and holding power.

[0030] The nanocomposite ceramic dielectric filler is composed of alumina and boron nitride in a mass ratio of 3:2. The alumina is AEROXIDE Alu C vapor-phase alumina (average particle size 50nm, specific surface area 100m² / g) produced by Evonik Industries, Germany, and the boron nitride is CoolFlow BN boron nitride nanosheets (average particle size 80nm) produced by 3M, USA, to uniformly distribute the electric field and improve the breakdown strength.

[0031] The silane coupling agent used is A-1100 γ-aminopropyltriethoxysilane produced by Momentive Advanced Materials Group of the United States, which is used to enhance the interfacial bonding between the nanocomposite ceramic dielectric filler and natural rubber.

[0032] The phenolic resin vulcanizing agent used is SP-1045 octylphenolic resin (hydroxyl equivalent 150g / eq) produced by Sanreco International Group of the United States, which is used to form a CC crosslinking network with natural rubber to improve high temperature resistance.

[0033] The activator / acid acceptor is active zinc oxide (99.7% purity) produced by the French Ehrmann Group, used to promote the vulcanization reaction and stabilize the crosslinking network.

[0034] The other additives include antioxidants and processing oils, wherein the antioxidant is Vulkanox 4020 (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) produced by Lanxess Chemical AG of Germany, and the processing oil is RAE-140 aromatic oil produced by SsangYong Petrochemical Co., Ltd. of South Korea.

[0035] The substrate layer is made of Lumirror S10 PET film (38μm thick) manufactured by Toray Industries, Ltd. of Japan, which has excellent mechanical strength and electrical insulation properties.

[0036] The thickness of the adhesive layer is 25 μm.

[0037] The preparation method includes: S1: Weighing each component raw material according to the formula ratio, and plasticizing natural rubber and liquid polyisoprene in a mixer at 100°C for 10 minutes; S2: Adding tackifying resin, nano-composite ceramic dielectric filler, silane coupling agent, phenolic resin vulcanizing agent, activator / acid acceptor and other additives to the plasticized rubber obtained in step S1, and mixing at 100°C for 20 minutes to obtain a compound; S3: Dissolving the compound obtained in step S2 in toluene solvent to prepare a rubber solution with a solid content of 30%; S4 S3: The adhesive obtained in step S3 is uniformly coated onto the surface of the substrate layer using a precision coating method at a coating speed of 12 m / min and a coating thickness of 25 μm; S5: The substrate coated with the adhesive layer obtained in step S4 is sent into a hot air circulating oven for drying and heat curing treatment, using a segmented curing method: first, pre-curing at 130℃ for 4 minutes, and then main curing at 170℃ for 8 minutes; S6: The termination tape cured in step S5 is cooled to room temperature by a cooling roller and wound up under constant tension to obtain the termination tape.

[0038] Example 2 A high-voltage resistant, high-viscosity natural rubber termination tape includes a substrate layer and an adhesive layer coated on at least one side of the substrate layer.

[0039] The adhesive layer comprises, by weight percentage, the following components: 45% natural rubber, 8% liquid polyisoprene, 25% tackifying resin, 5% nanocomposite ceramic dielectric filler, 0.5% silane coupling agent, 3% phenolic resin vulcanizing agent, 3% activator / acid acceptor, and the balance of other additives.

[0040] The natural rubber mentioned is SMR20 standard rubber produced by the Rubber Board of Malaysia (Mounney viscosity ML(1+4) 100℃ is 85).

[0041] The liquid polyisoprene used is IP Polymer liquid polyisoprene (number average molecular weight 15,000, cis-1,4 structure content 95%) manufactured by Idemitsu Kosan Co., Ltd. of Japan.

[0042] The tackifying resin used is Pine Crystal KR-85 rosin resin manufactured by Arakawa Chemical Industry Co., Ltd. of Japan.

[0043] The nanocomposite ceramic dielectric filler is composed of silica and barium titanate in a mass ratio of 1:1. The silica is HDK H20 fumed silica (average particle size 30nm) produced by Wacker Chemie GmbH, Germany, and the barium titanate is BT-05 barium titanate (average particle size 50nm) produced by Fuji Titanium Industry Co., Ltd., Japan.

[0044] The silane coupling agent used is Z-6040 γ-glycidyl etheroxypropyltrimethoxysilane manufactured by Dow Corning Incorporated.

[0045] The phenolic resin vulcanizing agent used is PR-515 phenolic resin (hydroxyl equivalent 180g / eq) produced by Henson Chemical Company, USA.

[0046] The activator / acid acceptor is MgO-98 activated magnesium oxide manufactured by Kyowa Chemical Industry Co., Ltd. of Japan.

[0047] The substrate layer is a Kapton HN polyimide film (50 μm thick) manufactured by DuPont.

[0048] The thickness of the adhesive layer is 40 μm.

[0049] The preparation method is the same as in Example 1, except that: in step S1, the plasticizing temperature is 120℃ and the plasticizing time is 5 minutes; in step S2, the mixing temperature is 120℃ and the mixing time is 15 minutes; in step S3, the solid content is 40%; in step S4, the coating speed is 20m / min and the coating thickness is 40μm; in step S5, the material is first pre-cured at 120℃ for 5 minutes and then mainly cured at 160℃ for 10 minutes.

[0050] Example 3 A high-voltage resistant, high-viscosity natural rubber termination tape includes a substrate layer and an adhesive layer coated on at least one side of the substrate layer.

[0051] The adhesive layer comprises, by weight percentage, the following components: 30% natural rubber, 15% liquid polyisoprene, 15% tackifying resin, 12% nanocomposite ceramic dielectric filler, 2% silane coupling agent, 8% phenolic resin vulcanizing agent, 1% activator / acid acceptor, and the balance of other additives.

[0052] The natural rubber used is SIR20 standard rubber (Mounney viscosity ML(1+4) 65 at 100°C) produced by PT Bakrie Sumatera Plantations in Indonesia.

[0053] The liquid polyisoprene used is SKI-3P liquid polyisoprene (number average molecular weight 45,000, cis-1,4 structure content 93%) produced by Nizhnekamskneftekhim Company of Russia.

[0054] The tackifying resin used is Koresin p-tert-butylphenol acetylene resin manufactured by BASF, Germany.

[0055] The nanocomposite ceramic dielectric filler is composed of alumina, boron nitride and silicon dioxide in a mass ratio of 2:1:2. The alumina is ATH-03 aluminum hydroxide (average particle size 80nm) produced by Aluminum Corporation of China, the boron nitride is Carbotherm BN boron nitride (average particle size 60nm) produced by Saint-Gobain, Inc., USA, and the silicon dioxide is QS-40 fumed silica (average particle size 40nm) produced by Tokuyama Corporation, Japan.

[0056] The silane coupling agent used is A-151 vinyltriethoxysilane produced by Hubei Xinlantian New Materials Co., Ltd., China.

[0057] The phenolic resin vulcanizing agent used is PF-8012 phenolic resin (hydroxyl equivalent 120g / eq) produced by Shandong Shengquan New Material Co., Ltd.

[0058] The active agent / acid acceptor is stearic acid (industrial grade, acid value 200-220 mg KOH / g).

[0059] The substrate layer is made of Lumirror S10 PET film (25μm thick) manufactured by Toray Industries, Ltd. of Japan.

[0060] The thickness of the adhesive layer is 15 μm.

[0061] The preparation method is the same as in Example 1, except that: in step S1, the plasticizing temperature is 80℃ and the plasticizing time is 15 minutes; in step S2, the mixing temperature is 80℃ and the mixing time is 30 minutes; in step S3, the solid content is 20%; in step S4, the coating speed is 5m / min and the coating thickness is 15μm; in step S5, the material is first pre-cured at 140℃ for 3 minutes and then cured at 180℃ for 5 minutes.

[0062] Comparative Example 1 The difference between this comparative example and Example 1 is that the adhesive layer does not contain phenolic resin vulcanizing agent, and the corresponding component ratio is adjusted to 45% natural rubber, 15% liquid polyisoprene, 25% tackifying resin, 8% nanocomposite ceramic dielectric filler, 1.2% silane coupling agent, 2% activator / acid acceptor, and the balance of other additives.

[0063] Due to the lack of phenolic resin vulcanizing agent, this comparative example could not form a stable CC crosslinking network and exhibited significant creep at high temperatures. The heat shrinkage rate after 30 minutes at 150°C was as high as 2.5%, which was much higher than the 0.3% of Example 1, and the peel strength retention rate was only 45%, which was much lower than the 85% of Example 1.

[0064] Comparative Example 2 The difference between this comparative example and Example 1 is that the adhesive layer does not contain nano-composite ceramic dielectric filler, and the corresponding component ratio is adjusted to 46% natural rubber, 12% liquid polyisoprene, 28% tackifying resin, 1.2% silane coupling agent, 5% phenolic resin vulcanizing agent, 2% activator / acid acceptor, and the balance of other additives.

[0065] Due to the lack of nanocomposite ceramic dielectric filler, the electric field distribution in this comparative example is not uniform, resulting in a significant decrease in breakdown strength. After aging for 1000 hours at 800V DC voltage, the breakdown strength retention rate is only 65%, which is far lower than the 95% of Example 1, and the corona discharge phenomenon is obvious.

[0066] Comparative Example 3 The difference between this comparative example and Example 1 is that the adhesive layer does not contain silane coupling agent, and the corresponding component ratio is adjusted to 39.2% natural rubber, 12% liquid polyisoprene, 20% tackifying resin, 8% nanocomposite ceramic dielectric filler, 5% phenolic resin vulcanizing agent, 2% activator / acid acceptor, and the balance of other additives.

[0067] Due to the lack of silane coupling agent, the interfacial bonding force between the nanocomposite ceramic dielectric filler and natural rubber in this comparative example is weak, and the filler agglomerates. After aging for 1000 hours at 85°C and 85%RH, the peel strength retention rate is only 52%, which is far lower than 85% in Example 1, and microcracks appear at the interface.

[0068] Performance testing To verify the performance advantages of the high-voltage resistant natural rubber termination tape of the present invention, the termination tapes prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests, and the test results are shown in Table 1.

[0069] 1. Initial tack test: Refer to GB / T 4852-2002 standard, use the inclined plane rolling ball method to test the initial tack, the unit is N / 25mm.

[0070] 2. Peel strength retention rate test: Referring to GB / T 2792-2014 standard, test the 180° peel strength of the termination tape before and after aging for 1000 hours at 85°C and 85%RH, and calculate the peel strength retention rate.

[0071] 3. Heat shrinkage test: Cut the termination tape into standard size, heat it in an oven at 150°C for 30 minutes, measure its dimensional change, and calculate the shrinkage rate.

[0072] 4. Electrolyte Resistance Test: Immerse the termination tape in lithium-ion battery electrolyte (1M). In / EC+DMC), soak at 85°C for 24 hours, observe the appearance changes and test and calculate the peel force retention rate.

[0073] 5. Volume resistivity test: Refer to GB / T 1410-2006 standard and use a high resistance meter to test the volume resistivity of the adhesive layer.

[0074] Table 1 Performance Test Results

[0075] As can be seen from the test results in Table 1, the high-voltage resistant natural rubber termination tapes of Examples 1-3 exhibit excellent performance in all aspects. The initial tack is greater than 5 N / 25 mm, meeting the high viscosity requirements; after soaking in electrolyte at 85°C for 24 hours, the peel force ratio of the soaked tape to the unsoaked tape is greater than 80%, demonstrating good resistance to damp heat aging; the heat shrinkage rate is less than 0.4%, demonstrating excellent high-temperature dimensional stability; and the volume resistivity is greater than [missing value]. It exhibits excellent electrical insulation properties at Ω·cm.

[0076] In contrast, Comparative Example 1, lacking a phenolic resin vulcanizing agent, failed to form a stable CC crosslinking network, resulting in significant creep at high temperatures, a peel strength retention rate of only 45%, and a thermal shrinkage rate as high as 2.5%. Comparative Example 2, lacking a nanocomposite ceramic dielectric filler, failed to achieve a uniform electric field distribution. Comparative Example 3, lacking a silane coupling agent, exhibited weak interfacial bonding between the nanofiller and the rubber matrix, a peel strength retention rate of only 52%, and microcracks appeared at the interface.

[0077] The above test results fully demonstrate that the present invention achieves a balance of high viscosity, high voltage resistance, and long-term reliability through the synergistic effect of natural rubber and phenolic resin vulcanizing agent, the electric field homogenization effect of nanocomposite ceramic dielectric filler, and the interface enhancement effect of silane coupling agent. Each component is indispensable and together constitutes the core technical advantage of the present invention.

[0078] In summary, the embodiments of this application have at least the following technical effects: Compared with the prior art, this application firstly avoids the performance degradation problem caused by the degradation of acrylic pressure-sensitive adhesive in the electrolyte by using natural rubber as a highly elastic matrix. Secondly, this application achieves a balance between high-temperature stability and electrolyte corrosion resistance by constructing a CC crosslinking network using phenolic resin vulcanizing agent. Thirdly, this application uniformizes the electric field distribution and significantly improves the breakdown strength by introducing nanocomposite ceramic dielectric filler. Finally, this application achieves uniform dispersion and strong interfacial bonding of nanofillers by applying silane coupling agent, suppressing interfacial discharge and electrical tree aging. Thus, it comprehensively solves all the defects of traditional termination tapes and significantly improves the safety and reliability of 800V and above high-voltage power batteries.

[0079] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

Claims

1. A high-voltage resistant, high-viscosity natural rubber termination tape, characterized in that, It includes a substrate layer and an adhesive layer coated on at least one side of the substrate layer; The adhesive layer comprises, by weight percentage, the following components: Natural rubber 30-45%, liquid polyisoprene 8-15%, tackifying resin 15-25%, nano-composite ceramic dielectric filler 5-12%, silane coupling agent 0.5-2%, phenolic resin vulcanizing agent 3-8%, activator / acid acceptor 1-3%, other additives balance.

2. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The natural rubber is smoked sheet rubber or standard rubber, with a Mooney viscosity ML(1+4) of 60~90 at 100℃.

3. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The liquid polyisoprene has a number average molecular weight of 10,000 to 50,000 and a cis-1,4 structure content of more than 90%.

4. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The tackifying resin is at least one of rosin resin, terpene resin, or C5 / C9 petroleum resin.

5. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The nanocomposite ceramic dielectric filler is composed of at least two of alumina, silicon dioxide, boron nitride, or barium titanate, with an average particle size of 20-100 nm.

6. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The phenolic resin vulcanizing agent is a linear phenolic resin or a thermosetting phenolic resin, with a hydroxyl equivalent of 100~200 g / eq.

7. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The activator / acid acceptor is at least one of zinc oxide, stearic acid, or magnesium oxide.

8. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or vinyltriethoxysilane.

9. The high-voltage resistant, high-viscosity natural rubber termination tape according to claim 1, characterized in that, The substrate layer is a polyethylene terephthalate film or a polyimide film with a thickness of 25~100μm.

10. A method for preparing a high-voltage resistant, high-viscosity natural rubber termination tape, characterized in that, Includes the following steps: S1: Weigh each component raw material according to the formula ratio, and plasticize natural rubber and liquid polyisoprene in an internal mixer at 80~120℃ for 5~15 minutes; S2: Add tackifying resin, nano-composite ceramic dielectric filler, silane coupling agent, phenolic resin vulcanizing agent, activator / acid acceptor and other additives to the plasticized rubber obtained in step S1, and mix at 80~120℃ for 15~30 minutes to obtain the compounded rubber. The mixing temperature is 100℃ and the mixing time is 20 minutes; S3: Dissolve the compound obtained in step S2 in an organic solvent to prepare a rubber solution with a solid content of 20-40%. S4: Apply the adhesive obtained in step S3 evenly to the surface of the substrate layer using a precision coating method. The coating speed is 5~20m / min and the coating thickness is 15~50μm. S5: The substrate coated with adhesive layer obtained in step S4 is sent into a hot air circulating oven for drying and heat curing treatment. The curing temperature is 120~180℃ and the curing time is 5~15 minutes. The thermosetting process adopts a segmented curing method, first pre-curing at 120~140℃ for 3~5 minutes, and then main curing at 160~180℃ for 5~10 minutes; S6: Cool the cured termination tape from step S5 to room temperature using a cooling roller, and then wind it up under constant tension to obtain the termination tape.

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