High-insulation fluorosilicone modified PET release film for solid-state battery pole piece lamination process

Abstract

The invention belongs to the field of functional film materials, discloses a high-insulation fluorosilicone modified PET release film for a solid-state battery pole piece lamination process, and solves the problems of high-temperature migration, high ion residue and insufficient dielectric strength of the existing release film. The release film comprises a PET base film subjected to corona or Ar plasma treatment and a fluorosilicone stripping layer coated on the surface of the PET base film, the fluorine-silicon stripping layer is composed of a fluorine-silicon modified acrylate copolymer with a ternary grafting structure, an organic silicon cross-linking agent with a specific structure, a fluorine-containing surface conditioning agent and a mixed solvent, the curing temperature is 100-110 DEG C, and the curing time is 2 min. According to the invention, the synergism of low stripping force, low ion residue, no silicon migration and high dielectric strength is realized, a solid-state battery lamination process is adapted, and the cycle stability of the battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of functional thin film materials, specifically relating to a highly insulating fluorosilicone modified PET release film for hot-pressing lamination processes of solid-state battery electrodes, electrolyte membranes, and current collectors. It is particularly suitable for precision lamination processing of solid-state batteries with different systems such as sulfides and oxides, and can meet the stringent requirements for high-temperature stability, interface cleanliness, and electrical insulation performance in solid-state battery manufacturing. Background Technology

[0002] Solid-state batteries, with their outstanding advantages such as high energy density and excellent safety performance, have become an important development direction in the field of new energy batteries. In their manufacturing process, the hot-pressing lamination process of the electrode, electrolyte membrane, and current collector is a key step that determines the quality of the battery interface bonding, electrochemical performance, and long-term stability. As a core auxiliary material in this lamination process, the release film must meet requirements such as dimensional stability under high-temperature environments, stable peel force, excellent electrical insulation, and extremely low interface residue to ensure the structural integrity and interface cleanliness of the electrode and electrolyte membrane after lamination.

[0003] In existing technologies, the release films commonly used in lamination processes mainly include two types: PET+silicone oil release films and conventional fluorosilicone modified PET release films. Among them, PET+silicone oil release films use PET as the base film and silicone oil as the release layer. They have a simple structure and low cost, but they have significant technical defects: under the high temperature conditions of 120-150℃ required for solid-state battery lamination, the low molecular weight components in the silicone oil are prone to migration and diffusion, leading to interface contamination between the electrode and the electrolyte membrane and damaging interfacial compatibility; at the same time, the viscosity change of silicone oil at high temperatures will cause large fluctuations in the peel force, and the electrodes and electrolyte membranes of solid-state batteries are usually brittle and easily damaged due to unstable peel force; in addition, the electrical insulation properties of silicone oil are limited and further degrade at high temperatures, making it difficult to adapt to the use requirements of high-voltage systems in solid-state batteries.

[0004] Conventional fluorosilicone-modified PET release films, designed to improve the deficiencies of silicone oil-based products, use fluorosilicone resin instead of pure silicone oil as the release layer. However, they still have significant limitations: these release films are mostly designed for general applications such as electronic tapes and photovoltaic modules, without being optimized for the specific needs of solid-state battery lamination processes. Their component ratios and molecular structure designs lack comprehensive consideration of "high-temperature migration resistance, stable peel strength, and high insulation," often only optimizing a single performance and failing to achieve a balance of multiple performances. Some solutions even limit the product solely through pure performance parameters, without clarifying the core structure and composition, making it difficult for those skilled in the art to reverse-engineer the product based on the parameters, thus lacking feasibility. Furthermore, conventional fluorosilicone-modified release films do not prioritize ion residue control, and their sodium content... + K +Impurity ions can easily migrate to the solid-state battery interface, causing electrolyte decomposition or internal short circuits, affecting battery performance. Existing conventional fluorosilicone modified release films contain Na... + / K + The residual amount is usually 10-20 ppm. After being used in solid-state battery lamination, the capacity decay rate of the battery reaches 15-20% after 50 cycles, while the tolerance threshold of solid-state batteries to ion residues needs to be <5 ppm.

[0005] In summary, existing release films either suffer from structural design defects leading to an imbalance in overall performance, or are difficult to reproduce due to vague constraints. Neither can meet the stringent requirements of solid-state battery lamination processes for high-temperature stability, interface cleanliness, electrical insulation, and consistent peel force, thus hindering the industrialization of solid-state batteries. Therefore, there is an urgent need for a release film material that can be stably reproduced and achieve synergistic optimization of multiple performance characteristics through clearly defined structure and composition constraints. Summary of the Invention

[0006] In view of this, the present invention proposes a high-insulation fluorosilicone modified PET release film for solid-state battery electrode lamination process, aiming to solve the technical pain points of existing release films such as "limited pure performance that is difficult to reproduce, unbalanced comprehensive performance, and insufficient adaptability". Through clear product structure, component ratio and key parameter collaborative design, the technical solution is clearly feasible and multi-performance optimized.

[0007] The technical solution of the present invention is achieved as follows: The present invention provides a high-insulation fluorosilicone modified PET release film for solid-state battery electrode lamination process, comprising a PET base film that has undergone specific treatment and a fluorosilicone release layer coated on its surface. By systematically defining the base film structure, release layer composition and key preparation parameters, the product performance is ensured to be stable and reproducible.

[0008] In some implementations, the PET base film thickness is set to 20–40 μm and treated with corona or Ar plasma. This specific thickness range simultaneously satisfies the mechanical support requirements and thermal conductivity uniformity during lamination, avoiding substrate deformation due to excessive thinness or decreased lamination accuracy due to excessive thickness. Furthermore, corona or Ar plasma treatment breaks down the chemical inertness of the PET base film surface, increases surface polarity and roughness, and enhances the interfacial adhesion between the base film and the fluorosilicone release layer. This fundamentally suppresses interlayer separation that may occur during high-temperature lamination, laying a structural foundation for the stable performance of the subsequent release layer.

[0009] In some embodiments, the fluorosilicone release layer has a thickness of 0.25–0.45 μm and consists of 65–85% by mass of a fluorosilicone-modified acrylate copolymer, 8–15% of an organosilicon crosslinking agent, 1–3% of a fluorinated surface conditioner, and 10–20% of an organic solvent. The curing temperature is 100–110°C, and the curing time is 2 min. The limitation on the release layer thickness is based on functional balance. If it is too thin, a complete insulating and release functional layer cannot be formed; if it is too thick, the peel force will exceed the limit and internal stress cracks will easily occur. The synergistic design of the component ratio avoids the performance imbalance caused by the excess or deficiency of a single component, while specific curing conditions ensure that the crosslinking reaction is sufficient and does not damage the PET base film, forming a structurally stable release layer, thus solving the core problem of "difficulty in reproducing" in existing purely performance-limited solutions.

[0010] in: The structural formula of the fluorosilicone-modified acrylate copolymer is: ; The structural formula of the organosilicon crosslinking agent is: ; The structural formula of the fluorine-containing surface conditioner is: .

[0011] In some embodiments, the fluorosilicone-modified acrylate copolymer is a ternary graft copolymer of an acrylate backbone with fluoroalkyl and siloxane segments. The acrylate backbone provides strong adhesion to the PET base film, solving the defect of easy peeling of pure fluoro / silicone modified films; the fluoroalkyl segments impart low surface energy to the coating, providing structural support for stable low peel force; the siloxane segments improve the high-temperature stability of the coating and inhibit molecular migration. Through molecular-level synergy, the three achieve a unified performance of "low peel force, high heat resistance, and anti-migration".

[0012] In some embodiments, the fluoroalkyl group R1 in the fluorosilicone-modified acrylate copolymer is a C4-C8 fluoroalkyl group, and the degree of polymerization of the siloxane segment n = 50-500. The length of the fluoroalkyl carbon chain directly affects the surface energy. The C4-C8 range can achieve an optimal balance between low peel strength and coating stability. If it is too short, the surface energy will be insufficient, resulting in high peel strength. If it is too long, it will reduce the compatibility between the coating and the base film. The limitation of the degree of polymerization n of the siloxane segment is to ensure the crosslinking reaction activity. When n = 50-500, the segment has enough reaction sites to form a dense network, but it will not be too long, causing the copolymer viscosity to exceed the standard and affecting the coating film formation effect.

[0013] In some embodiments, R1 of the organosilicon crosslinking agent is a siloxane chain -Si(CH3)2-O-Si(CH3)3, and R2 is an alkoxysilyl group -(CH2)3-Si(OR)3. The siloxane segments can complement the siloxane units in the fluorosilicone-modified acrylate copolymer, enhancing the thermal stability of the crosslinking network; the alkoxysilyl group can chemically bond with the hydroxyl groups generated on the surface of the PET base film after activation treatment, further improving the interfacial adhesion between the release layer and the substrate, and avoiding interfacial failure during high-temperature lamination. This design is not a simple selection of conventional crosslinking agents, but a precise matching based on the interfacial interaction mechanism.

[0014] In some embodiments, the R of the fluorinated surface modifier is polytetrafluoroethylene:-(CF2CF2)n, where n=50-500, and the surface tension of the fluorosilicone release layer is ≤32mN / m. The polytetrafluoroethylene segments possess extremely low surface energy and excellent insulation properties. They form a "dual low surface energy system" with the fluoroalkyl groups in the fluorosilicone-modified acrylate copolymer, further optimizing the stability of the release force. Simultaneously, the dense structure of the fluorocarbon chains can block charge transport channels within the coating, significantly improving electrical insulation performance and meeting the requirements of high-voltage systems in solid-state batteries. The limitation of n=50-500 ensures that the modifier is uniformly dispersed in the release layer, avoiding localized aggregation that could lead to performance fluctuations.

[0015] In some embodiments, the crosslinking density of the fluorosilicone-modified acrylate copolymer is 0.2–0.4 mol / 100g. Crosslinking density is a key parameter for balancing the flexibility and heat resistance of the coating: if the crosslinking density is too low, the coating structure is loose, and chain segment migration and adhesive residue are prone to occur at high temperatures; if the crosslinking density is too high, the coating will become brittle, and cracks will easily occur during bending or lamination. The setting of this range is based on the optimal range screened by a large number of experiments, ensuring that the coating achieves a precise balance between high-temperature stability, mechanical flexibility and peel performance, and solving the contradiction of "heat resistance leads to brittleness, and flexibility leads to easy migration" in the prior art.

[0016] In some embodiments, the organic solvent is a toluene / methyl ethyl ketone (MEK) mixture or a toluene / ethyl acetate mixture, with a MEK mixing ratio of 7:3 or 6:4, and a MEK / ethyl acetate mixing ratio of 5:5. The mixed solvent system balances the solubility and coating adaptability of each component: the specific ratios of toluene and MEK, and toluene and ethyl acetate, can adjust the solvent's evaporation rate and viscosity, ensuring uniform dispersion of the fluorosilicone-modified acrylate copolymer, the silicone crosslinking agent, and the fluorinated surface conditioner, avoiding defects such as pinholes and craters during coating, while also ensuring the uniformity of the crosslinking reaction during curing, thus supporting consistent coating performance.

[0017] In some embodiments, the fluorosilicone release layer does not contain low-molecular-weight silicone oil, and Na + / K +Residual levels <5 ppm (ICP analysis). Low-molecular-weight silicone oil is a major source of high-temperature migration contamination in traditional release films; designs free of low-molecular-weight silicone oil avoid this risk at the source; while Na... + K + Plasma can easily trigger interfacial reactions or form conductive channels in solid electrolytes, leading to battery capacity decay or short circuits. Strictly controlling its residual amount is a design specific to the cleanliness requirements of solid-state battery interfaces.

[0018] In some implementations, the release film exhibits a peel strength retention rate of ≥80% at 120°C for 5 min and a thermal shrinkage rate of ≤0.4% at 150°C for 10 min. When used in solid-state battery electrode, electrolyte membrane, or current collector lamination processes, no detectable silicon migration (XPS characterization) is observed at the interface after peeling, and the electrochemical impedance of the solid-state battery increases by <5%. The achievement of peel strength retention and thermal shrinkage rate targets stems from the thermal stability of the fluorosilicone ternary graft copolymer and the density of the cross-linked network. The absence of silicon migration and the low impedance increase are the result of the synergistic effect of the absence of low-molecular-weight silicone oil, low ion residue, and high insulation performance, ultimately achieving a precise match between the release film performance and the requirements of solid-state battery processes.

[0019] The present invention has the following advantages over the prior art: This invention abandons the vague design of existing release films that are "limited by pure performance parameters." Through clear product structure, component ratios, and synergistic constraints of key parameters, the technical solution is clearly implementable, solving the core problem of traditional solutions being "like wishful thinking, difficult to reproduce." It allows those skilled in the art to stably obtain the target performance through structural and compositional adjustments. Compared to general fluorosilicone modified release films, this invention achieves molecular-level synergy between the low surface energy of fluorine, the high heat resistance of silicon, and the strong adhesion of acrylate through a ternary grafted structure design of fluorosilicone modified acrylate copolymers. This breaks the limitation of existing technologies that offer "excellent single performance but unbalanced overall performance." Simultaneously, the optimization of component ratios, control of crosslinking density, and selection of solvent systems further enhance the high-temperature stability, low migration, and high insulation of the coating, precisely adapting to the specific requirements of solid-state battery lamination processes. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is the XPS full spectrum of the solid-state battery electrode surface.

[0022] Figure 2This is a detailed spectrum of XPS silicon content on the surface of a solid-state battery electrode. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 1. Substrate treatment: Select a PET base film with a thickness of 25μm and activate its surface using a corona treatment process. After treatment, the surface tension of the base film reaches 42mN / m, which meets the interface bonding requirements for subsequent release layer coating and is ready for use. 2. Peeling layer formulation and dispersion: Weigh the following components precisely by weight: 70 parts of fluorosilicone modified acrylate copolymer: This copolymer is an acrylate main bonded with C6 fluoroalkyl groups (R1=C6F). 13 -) A ternary graft copolymer of methyl methacrylate, perfluorohexyl ethyl acrylate, and γ-methacryloxypropyltrimethoxysilane in a molar ratio of 5:3:2 was prepared by copolymerization. After purification by vacuum distillation, the crosslinking density was controlled to be 0.3 mol / 100g. Preparation method: methyl methacrylate, perfluorohexyl ethyl acrylate, and γ-methacryloxypropyltrimethoxysilane were added to a reactor in a molar ratio of 5:3:2. 0.5 parts of azobisisobutyronitrile were added as an initiator. The reaction was carried out at 80°C for 5 h under nitrogen protection. After purification by vacuum distillation, the target copolymer was obtained. 10 parts of organosilicon crosslinking agent: In its chemical structure, R1 is a siloxane chain -Si(CH3)2-O-Si(CH3)3 and R2 is an alkoxysilyl group -CH2)3-Si(OCH3)3, which has good crosslinking activity; Two parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=200), which can further optimize the surface properties of the release layer; 18 parts of toluene / butanone mixed solvent: the volume ratio of the two is 7:3, used to adjust the viscosity of the coating liquid; The above components were added to a high-speed disperser in sequence, the speed was set to 3000 r / min, and the dispersion was continued for 30 min. During the process, the state of the coating liquid was observed to ensure that there were no obvious particles or stratification, so as to obtain a uniform and stable fluorosilicone release layer coating liquid. 3. Coating and curing: The prepared coating liquid is evenly coated onto the surface of the activated PET base film using a doctor blade coater. The wet film thickness is controlled to be 2μm by adjusting the gap of the coater. The coated base film is then sent into an oven and cured at 100℃ for 2 minutes. After curing, it is naturally cooled to room temperature to obtain a conventional adaptable high-insulation fluorosilicone modified PET release film.

[0025] Example 2 1. Substrate treatment: Select a PET base film with a thickness of 38μm, activate it by corona treatment, and the surface tension after treatment is 41mN / m, ready for use; 2. Peeling layer formulation and dispersion: Weigh each component according to its mass fraction: 75 parts of fluorosilicone-modified acrylate copolymer: acrylate with C8 fluoroalkyl groups (R1=C8F) as the main link. 17 -) A ternary graft copolymer of siloxane segments (degree of polymerization n=400) with a crosslinking density of 0.35 mol / 100g. This copolymer improves the uniformity of fluorosilicone segment distribution by optimizing the monomer feeding sequence. 12 parts of organosilicon crosslinking agent: R1 is a siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is an alkoxysilyl group -(CH2)3-Si(OC2H5)3, which has good synergistic reaction with the siloxane chain segment in the copolymer; Two parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=300), which can effectively reduce the surface tension of the release layer; 11 parts of toluene / butanone mixed solvent: volume ratio 7:3, to ensure complete dissolution of each component; The above components were added to a high-speed disperser and dispersed at 3000 r / min for 30 min to obtain a uniform and transparent coating liquid. 3. Coating and curing: The wet film thickness is controlled to 2.2μm by using a doctor blade coating method. The coated base film is placed in a 120℃ oven for constant temperature curing for 3 minutes. After cooling, a high heat-resistant release film is obtained, which is suitable for electrolyte lamination process under high temperature conditions.

[0026] Example 3 1. Substrate treatment: Select a 25μm thick PET substrate film, activate it by corona treatment, and achieve a surface tension of 43mN / m for later use; 2. Peeling layer formulation and dispersion: Weigh the following components according to their mass fractions: 65 parts of fluorosilicone modified acrylate copolymer: It is a ternary graft copolymer of acrylate main link with C4 fluoroalkyl (R1=C4F9-) and siloxane segments (degree of polymerization n=200), with a crosslinking density of 0.25mol / 100g. The fluoroalkyl carbon chain length is relatively short, which further reduces the surface energy of the coating. 8 parts of organosilicon crosslinking agent: R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilane group -(CH2)3-Si(OCH3)3, the amount is suitable for low peel force requirements; Four parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=150), and the higher addition amount further optimizes the peeling performance; 23 parts of toluene / butanone mixed solvent: volume ratio 6:4. Adjust the solvent ratio to suit low viscosity coating requirements. Add each component to a high-speed disperser, set the speed to 2800 r / min, disperse for 25 min, and obtain a uniform fluorosilicone release layer coating liquid; 3. Coating and curing: The wet film thickness is controlled to be 1.5μm by doctor blade coating. The base film is then placed in a 90℃ oven for curing for 2 minutes. After cooling, a low-peel-force release film is obtained, which can meet the low-damage peeling requirements of brittle electrodes.

[0027] Example 4 1. Substrate treatment: Select a 50μm thick PET substrate film, activate it by corona treatment, and set the surface tension to 40mN / m for later use; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions as follows: 70 parts of fluorosilicone modified acrylate copolymer: acrylate with C6 fluoroalkyl groups (R1=C6F) as the main link. 13 -) is a ternary graft copolymer of siloxane segments (degree of polymerization n=350) with a crosslinking density of 0.4 mol / 100g. The higher crosslinking density improves the density of the coating. 12 parts of organosilicon crosslinking agent: R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilyl -(CH2)3-Si(OC2H5)3. Sufficient crosslinking agent ensures the integrity of the crosslinking network. Two parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=250), the high insulation of the fluorocarbon chain further improves the dielectric properties; 16 parts of toluene / butanone mixed solvent: volume ratio 7:3, to ensure the coating liquid has suitable fluidity; After adding each component to a high-speed disperser, disperse at 3000 r / min for 30 min to obtain a uniform coating liquid; 3. Coating and curing: The wet film thickness is controlled at 2.5μm by doctor blade coating. The base film is placed in a 130℃ oven for curing for 3 minutes. After cooling, a high dielectric strength release film is obtained, which is suitable for high voltage electrolyte lamination process. No cracking or migration occurs under high temperature of 150℃×1h.

[0028] Example 5 1. Substrate treatment: Select a 16μm thick PET substrate film, activate it by corona treatment, and set the surface tension to 42mN / m for later use; 2. Peeling layer formulation and dispersion: Weigh each component according to its mass fraction: 72 parts of fluorosilicone modified acrylate copolymer: acrylate with C6 fluoroalkyl groups (R1=C6F) as the main link. 13 -) is a ternary graft copolymer of siloxane segments (degree of polymerization n=250) with a crosslinking density of 0.2mol / 100g. The low crosslinking density balances coating flexibility and high-speed coating adaptability. 8 parts of organosilicon crosslinking agent: R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilyl-(CH2)3-Si(OCH3)3, the amount is suitable for high-speed processing requirements; 1.5 parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=180), which optimizes surface properties while avoiding affecting coating smoothness; 18.5 parts of toluene / ethyl acetate mixed solvent: volume ratio 5:5, the mixed solvent system is suitable for online high-speed dispersion and coating; A uniform and stable coating liquid was prepared by using an online high-speed dispersion device with a rotation speed of 3200 r / min and a dispersion time of 20 min. 3. Coating and curing: The wet film thickness is controlled at 1.2μm by a high-speed coating machine. The base film is sent into a 110℃ oven for curing for 1.5min. After cooling, a low-shrinkage high-speed coated release film is obtained. After 10 lamination / peeling cycles, the peel force fluctuation is controlled within ±0.8g / 25mm. It is suitable for high-speed die-cutting and continuous roll-to-roll processes.

[0029] Example 6 1. Substrate treatment: A 40μm thick PET base film was selected and surface activated using Ar plasma treatment. After treatment, the surface tension of the base film reached 45mN / m, which significantly improved the interfacial adhesion with the release layer. 2. Peeling layer formulation and dispersion: Weigh the following components according to their mass fractions: 73 parts of fluorosilicone-modified acrylate copolymer: acrylate with C6 fluoroalkyl groups (R1=C6F) as the main link. 13-) A ternary graft copolymer of siloxane segments (degree of polymerization n=300) with a crosslinking density of 0.35mol / 100g. By precisely controlling the ratio of fluorosilicone segments, it can meet the high voltage requirements of sulfide batteries. 13 parts of organosilicon crosslinking agent: R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilyl-(CH2)3-Si(OC2H5)3. Sufficient crosslinking agent ensures structural stability at high temperature. 2.5 parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=250), which further enhances the high insulation performance of the coating; 11.5 parts of toluene / butanone mixed solvent: volume ratio 7:3, to ensure that the coating liquid still has good fluidity at high solid content; Add each component to a high-speed disperser, set the speed to 3500 r / min, disperse for 35 min, and obtain a uniform and fine coating liquid. 3. Coating and curing: The wet film thickness is controlled at 2.3μm by doctor blade coating. The base film is placed in an oven at 115℃ for 2.5min for curing. After cooling, a release film for high-voltage sulfide solid-state batteries is obtained. After 100 cycles of sulfide solid-state batteries, the impedance increase of this product is only 2.5%, which shows excellent adaptability.

[0030] Example 7 1. Substrate treatment: Select a 30μm thick PET substrate film, activate it by corona treatment, and set the surface tension to 41mN / m for later use; 2. Peeling layer formulation and dispersion: Weigh each component according to its mass fraction: 74 parts of fluorosilicone modified acrylate copolymer: acrylate with C6 fluoroalkyl groups (R1=C6F) as the main link. 13 -) and ternary graft copolymer of siloxane segments (degree of polymerization n=300) are purified by vacuum distillation to remove ionic impurities, with a crosslinking density of 0.3mol / 100g, which meets the stringent requirements of oxide batteries for ion residue. 11 parts of organosilicon crosslinking agent: R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilyl -(CH2)3-Si(OCH3)3, and crosslinking agent raw materials with low ion content are selected; Two parts of fluorinated surface conditioner: R is polytetrafluoroethylene-(CF2CF2)n (n=200), which ensures low ion residue while optimizing peeling performance; 13 parts of toluene / ethyl acetate mixed solvent: volume ratio 6:4. The solvent is purified by distillation to reduce the content of impurity ions. Add each component to a high-speed disperser, set the speed to 3000 r / min, disperse for 30 min, and obtain a uniform coating liquid; 3. Coating and Curing: The wet film thickness was controlled to 2.0 μm using a doctor blade coating method. The base film was cured in a 110℃ oven for 2 minutes, then transferred to a 100℃ vacuum oven for 1 hour to further remove trace volatiles and potential impurity ions. After cooling, a low-ion residual oxide solid-state battery adaptable release film was obtained. Its Na... + / K + The residual amount is as low as 1.9 ppm, and the increase in interface impedance of oxide solid-state batteries is less than 2%.

[0031] Comparative Example 1 1. Substrate treatment: Consistent with Example 1, a 25μm thick PET substrate film was selected, activated by corona treatment, with a surface tension of 42mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 70 parts of fluorosilicone-modified acrylate copolymer: exactly the same as in Example 1, i.e., the acrylate main link is branched with C6 fluoroalkyl groups (R1=C6F). 13 -) a ternary graft copolymer of siloxane segments (degree of polymerization n=300), with a crosslinking density of 0.3mol / 100g; 10 parts of organosilicon crosslinking agent: consistent with Example 1, R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilyl-(CH2)3-Si(OCH3)3; Fluorine-containing surface conditioner 0 parts: This component was deliberately omitted to verify its necessity; 20 parts of toluene / butanone mixed solvent: volume ratio 7:3, to make up for the volume loss due to the lack of surface conditioner; The dispersion conditions were the same as in Example 1, and the coating liquid was prepared by dispersing at 3000 r / min for 30 min. 3. Coating and curing: Same as in Example 1, wet film thickness 2μm, cured at 100℃ for 2min, and the sample was obtained after cooling.

[0032] Comparative Example 2 1. Substrate treatment: Same as in Example 3, a 25μm thick PET substrate film was activated by corona treatment, with a surface tension of 43mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 65 parts of fluorosilicone modified acrylate copolymer: exactly the same as in Example 3, namely, a ternary graft copolymer of acrylate main linking C4 fluoroalkyl (R1=C4F9-) and siloxane segment (degree of polymerization n=200), with a crosslinking density of 0.25 mol / 100g; Three parts of organosilicon crosslinking agent: only 37.5% of the amount used in Example 3, deviating from the usage range of 15% in claim 8; Four parts of fluorinated surface conditioner: consistent with Example 3, R is polytetrafluoroethylene-(CF2CF3)n (n=150); 28 parts of toluene / butanone mixed solvent: volume ratio 6:4, make up the solvent volume; The dispersion conditions were the same as in Example 3, and the coating liquid was prepared by dispersing at 2800 r / min for 25 min. 3. Coating and curing: Same as in Example 3, wet film thickness 1.5 μm, cured at 90℃ for 2 min, and the sample was obtained after cooling.

[0033] Comparative Example 3 1. Substrate treatment: Same as in Example 4, a 50μm thick PET substrate film was activated by corona treatment, with a surface tension of 40mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 70 parts of fluorosilicone-modified acrylate copolymer: exactly the same as in Example 4, i.e., the acrylate main link is branched with C6 fluoroalkyl groups (R1=C6F). 13 -) a ternary graft copolymer with siloxane segments (degree of polymerization n=350), with a crosslinking density of 0.4 mol / 100g; 20 parts of organosilicon crosslinking agent: exceeding the dosage range of claim 8-15%, representing 166.7% of the dosage used in Example 4; Two parts of fluorinated surface conditioner: consistent with Example 4, R is polytetrafluoroethylene-(CF2CF2)n (n=250); 8 parts of toluene / butanone mixed solvent: volume ratio 7:3, adjust the amount of solvent to suit the proportion of high crosslinking agent; The dispersion conditions were the same as in Example 4, with dispersion at 3000 r / min for 30 min to obtain the coating liquid; 3. Coating and curing: The wet film thickness is 2.5 μm, the curing temperature is increased to 150℃, the curing time is extended to 5 min, and the sample is obtained after cooling.

[0034] Comparative Example 4 1. Substrate treatment: Same as in Example 5, a 16μm thick PET substrate film was activated by corona treatment, with a surface tension of 42mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 72 parts of silicone-modified acrylate copolymer: grafted only with siloxane segments (degree of polymerization n=250), without fluorinated alkyl grafting, deviating from the core structural limitation of "fluorosilicone modification" in the claims; 8 parts of organosilicon crosslinking agent: consistent with Example 5, R1 is siloxane chain -Si(CH3)2-O-Si(CH3)3, R2 is alkoxysilyl-(CH2)3-Si(OCH3)3; 0 parts of fluorinated surface conditioner: Due to the fluorine-free structure, the fluorinated surface conditioner is omitted. 20 parts of toluene / ethyl acetate mixed solvent: volume ratio 5:5, adjust the solvent volume accordingly; The dispersion conditions were the same as in Example 5, and the coating liquid was prepared by dispersing at 3200 r / min for 20 min. 3. Coating and curing: Same as in Example 5, wet film thickness 1.2 μm, cured at 110℃ for 1.5 min, and obtained the sample after cooling.

[0035] Comparative Example 5 1. Substrate treatment: Same as in Example 1, a 25μm thick PET substrate film was activated by corona treatment, with a surface tension of 42mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 35 parts of fluorinated modified acrylate copolymer: grafted only with C6 fluoroalkyl groups (R1=C6F) 13 -), without siloxane segments; Silicon-modified acrylate copolymer, 35 parts: grafted only with siloxane segments (degree of polymerization n=300), without fluorinated alkyl groups; The physical blending of the two copolymers described above, replacing the fluorosilicone ternary graft copolymer in Example 1, deviates from the core structural limitation of "intramolecular ternary grafting". 10 parts of organosilicon crosslinking agent: consistent with Example 1; Two parts of fluorinated surface conditioner: consistent with Example 1; 18 parts of toluene / butanone mixed solvent: volume ratio 7:3; The dispersion conditions were the same as in Example 1, and the coating liquid was prepared by dispersing at 3000 r / min for 30 min. 3. Coating and curing: Same as in Example 1, wet film thickness 2μm, cured at 100℃ for 2min, and the sample was obtained after cooling.

[0036] Comparative Example 6 1. Substrate treatment: Same as in Example 1, a 25μm thick PET substrate film was activated by corona treatment, with a surface tension of 42mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 70 parts of fluorosilicone-modified acrylate copolymer: exactly the same as in Example 1; 10 parts of organosilicon crosslinking agent: exactly the same as in Example 1; Two parts of non-fluorinated surface conditioner: polyether-modified silicone oil is selected to replace the fluorinated surface conditioner as defined in the claims; 18 parts of toluene / butanone mixed solvent: volume ratio 7:3; The dispersion conditions were the same as in Example 1, and the coating liquid was prepared by dispersing at 3000 r / min for 30 min. 3. Coating and curing: Same as in Example 1, wet film thickness 2μm, cured at 100℃ for 2min, and the sample was obtained after cooling.

[0037] Comparative Example 7 1. Substrate treatment: Same as in Example 1, a 25μm thick PET substrate film was activated by corona treatment, with a surface tension of 42mN / m; 2. Peeling layer formulation and dispersion: Weigh the components according to their mass fractions: 70 parts of fluorosilicone-modified acrylate copolymer: exactly the same as in Example 1; 10 parts of organosilicon crosslinking agent: R1 = methyl, R2 = methyl, without alkoxysilane groups, deviating from the structural definition of the crosslinking agent in the claims; Two parts of fluorinated surface conditioner: consistent with Example 1; 18 parts of toluene / butanone mixed solvent: volume ratio 7:3; The dispersion conditions were the same as in Example 1, and the coating liquid was prepared by dispersing at 3000 r / min for 30 min. 3. Coating and curing: Same as in Example 1, wet film thickness 2μm, cured at 100℃ for 2min, and the sample was obtained after cooling.

[0038] Comparative Example 8 1. Substrate treatment: A 25μm thick PET substrate film was selected, without corona or plasma treatment, and the surface tension was only 28mN / m, which deviates from the limitation of "substrate being activated" in the claims; 2. Preparation and dispersion of the peeling layer: The preparation and dispersion conditions are completely consistent with those in Example 1; 3. Coating and curing: The coating and curing conditions were exactly the same as in Example 1, and the sample was obtained after cooling.

[0039] Performance verification 1. Peel strength test: Referring to GB / T2792-2014 standard, an electronic tensile testing machine was used to test the 180° peel strength of the samples against the polyolefin adhesive under the following conditions: room temperature of 25℃ and corresponding high temperature conditions (120℃ for conventional type, 150℃ for high heat resistance type, 150℃ for high dielectric type, and 100℃ for low shrinkage type). The test speed was set to 300mm / min. Each group of samples was tested in parallel for 3 times, and the arithmetic mean was taken as the final result. 2. Heat shrinkage rate test: According to ASTM D1204 standard, each sample was cut into 100mm×100mm square specimens, the baseline was marked, and the specimens were placed in a 150℃ constant temperature oven for 10 minutes. After being removed, the specimens were allowed to cool naturally to room temperature. The change in the length of the baseline of the specimens was measured using a vernier caliper with an accuracy of 0.01mm, and the heat shrinkage rate was calculated. 3. Dielectric strength test: In accordance with ASTM D149 standard, a dielectric strength tester was used to test the dielectric strength of the samples at room temperature and 60%RH environment with a voltage rise rate of 500V / s. Each group was tested 3 times, and the minimum value was taken as the final result. 4. Surface resistivity test: Referring to ASTM D257 standard, a high-resistivity meter was used to test the surface resistivity of the samples at room temperature and 60% RH. A suitable electrode system was selected, and each group was tested 3 times and the average value was taken. 5.Na + / K + Residue testing: ICP-MS analysis was used. The sample was cut into fragments and placed in a polytetrafluoroethylene digestion vessel. Superior purity nitric acid was added, and the mixture was completely digested using a microwave digester. The volume was then adjusted to a specific level, and the Na+ content in the digestion solution was measured using ICP-MS. + K + The concentration is used to calculate the residual ion content per unit area of ​​the sample. 6. Silicon migration test: X-ray photoelectron spectroscopy (XPS) is used to perform full-spectrum scanning and fine silicon elemental spectrum analysis on the surface of the solid-state battery electrode after lamination and peeling to detect the presence of silicon on the electrode surface and determine whether silicon migration has occurred in the peeling layer. 7. Battery performance testing: The samples of each example and comparative example were used in the corresponding solid-state battery electrode lamination process to prepare CR2032 button batteries. At room temperature, charge-discharge cycle tests were conducted at a rate of 0.1C. The battery capacity retention rate and electrochemical impedance change rate were recorded after 50 cycles (100 cycles for Example 6). 8. Specific performance tests: For example 7, a 180° reciprocating bending test was conducted. After 10 bends, the peeling layer was observed for cracking or peeling, and the cracking rate was calculated. For example 6, an environmental stability test was conducted. The sample was placed in an environment of 85%RH and 25℃ for 72 hours, and the peeling force at 25℃ was retested, and the peeling force fluctuation value was calculated. For example 8, a high-temperature interfacial bonding test was conducted. The laminated sample was placed in a 120℃ oven for 2 hours. After removal, the peeling layer edges were observed for lifting or peeling, and the peeling rate was calculated.

[0040] Performance Results

[0041] A performance comparison of Examples 1-7 and Comparative Examples 1-9 shows that this invention, through the ternary grafting structure design of fluorosilicone-modified acrylate copolymers, specific component ratios, and process parameter control, achieves synergistic compliance with low peel force, high dielectric strength, low thermal shrinkage, low ion residue, and no migration, fully meeting the requirements of solid-state battery lamination processes. Comparative Example 1, lacking a fluorinated surface conditioner, resulted in a surge in peel force and decreased stability. Comparative Examples 2-3, deviating from the crosslinking agent dosage range, caused adhesive residue or coating embrittlement. Comparative Example 4, with its fluorine-free structure, and Comparative Example 5, with its physical blend system, failed to achieve multiple performance characteristics simultaneously. Comparative Examples 6-8, after replacing key components or omitting substrate treatment, showed significant degradation in core indicators such as insulation and interfacial adhesion. Comparative Example 9, with its commercially available general-purpose film, suffered from prominent ion residue and migration issues due to a lack of customized design, leading to a significant decrease in battery performance. In summary, the synergistic interaction of the core structure, component ratios, and process constraints of this invention is key to achieving comprehensive performance advantages. It is not a simple combination or parameter optimization of existing technologies, demonstrating significant inventiveness and practicality.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high insulation fluorosil modified PET release film for solid state battery electrode sheet lamination process characterized by, The application relates to a fluorosilicon release film for solid-state battery electrode, electrolyte film or current collector laminating process. The fluorosilicon release film comprises a PET base film with a thickness of 20-40 mu m, which is treated by a corona or Ar plasma; a fluorosilicon release layer is coated on the surface of the PET base film and has a thickness of 0.25-0.45 mu m, and is composed of 65-85% of a fluorosilicon modified acrylate copolymer, 8-15% of an organic silicon crosslinking agent, 1-3% of a fluorine-containing surface modifier and 10-20% of an organic solvent, and the curing condition of the fluorosilicon release layer is 100-110 DEG C * 2 min. The dielectric strength of the release film is greater than or equal to 120 kV / mm, and the release force of the release film to a polyolefin adhesive at 25 DEG C is 10-15 g / 25 mm. The fluorosilicone-modified acrylate copolymer is a ter-graft copolymer of acrylate main chain branched with fluoralkyl and siloxane segments, and the structural formula of the fluorosilicone-modified acrylate copolymer is: ; The structural formula of the organic silicon crosslinking agent is: ; The structural formula of the fluorine-containing surface modifier is: ; In the fluorosilicon modified acrylate copolymer, a fluorine alkyl R1 is a C4-C8 fluorine alkyl, and the polymerization degree n of a siloxane chain segment is 50-500.

2. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The R1 of the organic silicon crosslinking agent is a siloxane chain-Si (CH3) 2-O-Si (CH3) 3, and the R2 is an alkoxy silicon group-(CH2) 3-Si (OR) 3.

3. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The R of the fluorine-containing surface modifier is a polytetrafluoroethylene-(CF2CF2) n, n=50-500, and the surface tension of the fluorosilicon release layer is less than or equal to 32 mN / m.

4. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The crosslinking density of the fluorosilicon modified acrylate copolymer is 0.2-0.4 mol / 100 g.

5. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The organic solvent is a toluene / butyronitrile mixed system or a toluene / ethyl acetate mixed system, the mixing ratio of toluene / butyronitrile is 7:3 or 6:4, and the mixing ratio of toluene / ethyl acetate is 5:

5.

6. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The release force retention rate of the release film at 120 DEG C * 5 min is greater than or equal to 80%, and the thermal shrinkage rate at 150 DEG C * 10 min is less than or equal to 0.4%.

7. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The fluorosilicon release layer does not contain low-molecular silicone oil, and Na + / K + Residual amount < 5 ppm.

8. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, The fluorosilicon release film is used for solid-state battery electrode, electrolyte film or current collector laminating process, no detectable silicon migration exists at the interface after release, and the electrochemical impedance of the solid-state battery is increased by less than 5%.

9. The highly insulating fluorosilicon modified PET release film according to claim 1, wherein, ​

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