Non-silicon release agent for high-performance battery adhesive tape and preparation method of non-silicon release agent

Abstract

The invention discloses a non-silicon release agent for a high-performance battery adhesive tape. The non-silicon release agent is prepared from 4-6 parts of modified synthetic liquid, 2-6 parts of amino resin, 4-9 parts of a functional diluent, 7-12 parts of a composite solvent and 0.1-0.5 part of a nano additive, a preparation method of the modified synthetic liquid comprises the following steps: S1, uniformly mixing a first monomer, a fluorine-containing monomer and a butanone-ethanol mixed solvent, introducing nitrogen to remove oxygen, heating to 60-70 DEG C, and keeping for 30-50 minutes; s2, adding a second monomer, an initiator and a chain transfer agent into the mixed solution obtained in the step S1, and reacting at 65-75 DEG C for 5-7 hours; and S3, heating the mixed solution obtained in the step S2 to 80-90 DEG C, then adding a first monomer and an initiator in three times, and reacting for 1-1.5 hours each time to obtain the modified synthetic solution. The non-silicon release agent for the high-performance battery adhesive tape provided by the invention is in a liquid form, does not need to be dissolved by heating, has no particle pollution, and is superior to the prior art in release force stability, chemical resistance and heat resistance.

Description

Technical Field

[0001] This invention relates to the field of non-silicone release agent technology, specifically to a high-performance non-silicone release agent for battery tape and its preparation method. Background Technology

[0002] Lithium-ion battery tapes need to possess strong adhesion, heat resistance, and electrolyte resistance. The performance of the release layer on the back directly affects the tape's production efficiency and user experience. In existing technologies, non-silicone release agents used in battery tapes are mostly in powder form, requiring heating to 50-60℃ to dissolve and maintaining a constant temperature for use, which is cumbersome. Furthermore, powdered release agents are prone to generating tiny particles, leading to poor tape appearance.

[0003] While existing liquid non-silicone release agents have solved the above problems, their release force tends to fluctuate and residual adhesion decreases significantly under long-term contact with electrolytes or high-temperature environments, making it difficult to meet the requirements of high-reliability battery production. Therefore, developing a non-silicone release agent that combines convenience, excellent appearance, and high stability has become an urgent technical problem to be solved. Summary of the Invention

[0004] The present invention aims to address the shortcomings of existing non-silicone release agents in terms of electrolyte resistance and high-temperature release stability, and provides a high-performance non-silicone release agent for battery tapes. It is in liquid form, does not require heating to dissolve, has no particulate contamination, and is superior to existing technologies in terms of release force stability, chemical resistance, and heat resistance.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] The first aspect of the present invention provides a high-performance non-silicone release agent for battery tape, comprising the following components in parts by weight: 4-6 parts of modified synthetic liquid, 2-6 parts of amino resin, 4-9 parts of functional diluent, 7-12 parts of composite solvent, and 0.1-0.5 parts of nano-additives.

[0007] The preparation method of the modified synthetic liquid includes the following steps:

[0008] S1. Mix the first monomer, the fluorinated monomer and the butanone-ethanol mixed solvent evenly, purge with nitrogen to remove oxygen, and then heat to 60-70℃ and maintain for 30-50 minutes.

[0009] S2. Add the second monomer, initiator and chain transfer agent to the mixture obtained in step S1, and then react at 65-75°C for 5-7 hours;

[0010] S3. Heat the mixture obtained in step S2 to 80-90°C, and then add the first monomer and initiator in three batches, each reaction lasting 1-1.5 hours, to obtain the modified synthetic solution.

[0011] Further, in step S1, the first monomer is butyl acrylate, and the amount added is 420-480 parts; the fluorinated monomer is trifluoroethyl methacrylate, and the amount added is 10-15 parts; the amount added is 90-110 parts of the butanone-ethanol mixed solvent.

[0012] Further, in step S2, the second monomer comprises: 65-85 parts of dodecyl acrylate, 18-22 parts of hydroxyethyl methacrylate, and 18-22 parts of butyl acrylate.

[0013] Further, in step S2, the initiator is benzoyl peroxide, and the amount added is 3 to 5 parts; the chain transfer agent is dodecyl mercaptan, and the amount added is 0.5 to 1 part.

[0014] Furthermore, in step S3, the first monomer added each time is 10 to 15 parts, and the initiator is 0.8 to 1.2 parts.

[0015] Furthermore, the nano-auxiliary agent is nano-silica with a surface modified by a silane coupling agent and a particle size of 50-100 nm.

[0016] In this invention, adding nano-silica (particle size 50-100 nm) modified with a silane coupling agent to the release agent can improve the wear resistance and electrolyte resistance of the release layer. Specifically, the nano-silica modified with a silane coupling agent and the fluorine-containing groups produce a synergistic effect, effectively preventing release layer failure caused by electrolyte penetration: on the one hand, after modification with the silane coupling agent, a micro-nano roughness structure is formed on the surface of the release layer, reducing the contact area and lowering the surface energy of the release layer; on the other hand, the low polarizability and strong electronegativity of fluorine atoms further reduce the surface energy; the protruding structure of the nanoparticles can "anchor" the fluorine-containing segments to the surface, forming a "lotus effect", which can increase the electrolyte contact angle from 90° to over 110°, significantly reducing the risk of liquid wetting. On the other hand, nano-silica forms a three-dimensional network structure in the polymer matrix, extending the penetration path of small molecules, while the fluorinated groups are chemically inert to carbonate electrolytes, forming a molecular-level repulsion layer at the interface, thus reducing the electrolyte permeability. This synergistic effect enables the release layer to maintain low surface energy while possessing excellent chemical resistance and mechanical stability, making it particularly suitable for the long-term use requirements of lithium-ion battery tapes in electrolyte environments.

[0017] Furthermore, the amino resin is composed of amino resin 303LF and melamine-formaldehyde resin mixed at a mass ratio of 3:1.

[0018] In this invention, amino resin 303LF and melamine-formaldehyde resin are mixed at a mass ratio of 3:1, which can improve the crosslinking density and heat resistance.

[0019] Furthermore, the functional diluent is a mixture of 1,4-cyclohexanediethanol and trimethylolpropane in a mass ratio of 4:1.

[0020] In this invention, 1,4-cyclohexanediethanol and trimethylolpropane are mixed at a mass ratio of 4:1 as a diluent, which enhances the dilution effect and improves the flexibility of the release layer.

[0021] Furthermore, the composite solvent is composed of butanone, isopropanol and ethyl acetate in a mass ratio of 2:2:1.

[0022] In this invention, methyl ethyl ketone, isopropanol and ethyl acetate are mixed in a mass ratio of 2:2:1 as a solvent, which can balance solubility and volatility, reduce VOC emissions and improve coating leveling properties.

[0023] The second aspect of the present invention provides a method for preparing the high-performance non-silicone release agent for battery tape, comprising: mixing modified synthetic liquid, amino resin, functional diluent, composite solvent and nano-additive in the prescribed amounts at 30-40°C for 30-40 minutes, with a stirring speed of 300-500 rpm, thereby obtaining the non-silicone release agent for battery tape.

[0024] The third aspect of the present invention provides a coating method for the non-silicone release agent for high-performance battery tape, comprising: mixing 8-12 parts of non-silicone release agent for battery tape, 1-2 parts of composite curing agent and 45-55 parts of composite solvent to obtain a coating liquid; coating the coating liquid onto the surface of a substrate, and curing it at 110-115°C for 1.5-2 minutes to obtain a release layer;

[0025] The composite curing agent is obtained by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 4:1, and then mixing it with isopropanol in a mass ratio of (20-30):(70-80).

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The high-performance non-silicone release agent for battery tapes provided by this invention, through a stepwise polymerization process and modification with fluorinated monomers, achieves a release force fluctuation of ≤5% during long-term storage or high-temperature environments, significantly superior to traditional technologies. Experiments show that after aging at 70℃ for 48 hours, the release force retention rate is ≥95%, and the residual adhesion is ≥93%, meeting the requirements for high-end battery tapes.

[0028] 2. The high-performance non-silicone release agent for battery tape provided by the present invention, through the synergistic effect of introducing nano-silica and fluorine-containing groups, after the release layer is immersed in a mixed electrolyte of ethylene carbonate / dimethyl carbonate (EC / DMC) for 72 hours, the change rate of release force is ≤10%, while that of traditional technology is usually above 30%. In practical applications, it can effectively prevent the release layer failure problem caused by electrolyte penetration.

[0029] 3. The high-performance non-silicone release agent for battery tapes provided by this invention uses a low-VOC composite solvent system (VOC content ≤50g / L), which meets environmental regulations and reduces emissions by more than 40% compared to traditional solvent-based release agents. Its liquid form eliminates the need for heating to dissolve, simplifying the production process and reducing energy consumption by approximately 30%. Detailed Implementation

[0030] 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 them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a high-performance non-silicone release agent for battery tapes, comprising the following components by weight: 5 parts modified synthetic liquid, 4 parts amino resin, 6 parts functional diluent, 10 parts composite solvent, and 0.3 parts nano-silica (80nm particle size, KH-570 modified). The amino resin comprises 303LF and melamine-formaldehyde resin (in a 3:1 ratio), the functional diluent comprises 1,4-cyclohexanediol and trimethylolpropane (in a 4:1 ratio), and the composite solvent comprises butanone, isopropanol, and ethyl acetate (in a 2:2:1 ratio).

[0033] The preparation method of the non-silicone release agent in this embodiment is as follows: stir the above components at 35°C and 400 rpm for 35 minutes to obtain a liquid non-silicone release agent.

[0034] In this embodiment, the method for synthesizing the modified synthetic solution includes the following steps:

[0035] S1: 450 parts butyl acrylate, 12 parts trifluoroethyl methacrylate and 100 parts butanone-ethanol mixed solvent (mass ratio 1:1) are purged with nitrogen for 30 minutes to remove oxygen, and then heated to 65°C and held for 40 minutes.

[0036] S2: Add 75 parts dodecyl acrylate, 20 parts hydroxyethyl methacrylate, 20 parts butyl acrylate, 4 parts benzoyl peroxide, and 0.8 parts dodecyl mercaptan, and react at 70°C for 6 hours.

[0037] S3: Heat to 85℃, add butyl acrylate (12 parts each time) and benzoyl peroxide (1 part each time) in three portions, reacting for 1.2 hours each time to obtain the modified synthesis solution.

[0038] The coating process for the non-silicone release agent in this embodiment is as follows:

[0039] (1) Coating liquid formulation: 10 parts of non-silicone release agent, 1.5 parts of composite curing agent (p-toluenesulfonic acid: phosphoric acid = 4:1, diluted to 25% isopropanol solution), and 50 parts of composite solvent.

[0040] (2) Coating was performed on a PET substrate (25μm) using a microgravure coating machine, with a coating amount of 0.4g / m². 2 Cured at 112℃ for 1.8 minutes.

[0041] Example 2

[0042] This embodiment provides a high-performance non-silicone release agent for battery tapes, comprising the following components by weight: 4 parts modified synthetic liquid, 3 parts amino resin, 8 parts functional diluent, 12 parts composite solvent, and 0.2 parts nano-silica (100nm particle size, KH-560 modified). The amino resin comprises 303LF and melamine-formaldehyde resin (in a 4:1 ratio), the functional diluent comprises 1,4-cyclohexanediol and trimethylolpropane (in a 5:1 ratio), and the composite solvent comprises butanone, isopropanol, and ethyl acetate (in a 3:2:1 ratio).

[0043] The preparation method of the non-silicone release agent in this embodiment is as follows: stir the above components at 30°C and 300 rpm for 40 minutes to obtain a liquid non-silicone release agent.

[0044] In this embodiment, the method for synthesizing the modified synthetic solution includes the following steps:

[0045] S1: 420 parts butyl acrylate, 10 parts trifluoroethyl methacrylate and 90 parts butanone-ethanol mixed solvent (1:1) are purged with nitrogen gas to remove oxygen for 40 minutes, and then heated to 60°C and held for 50 minutes.

[0046] S2: Add 65 parts dodecyl acrylate, 18 parts hydroxyethyl methacrylate, 18 parts butyl acrylate, 3 parts benzoyl peroxide, and 0.5 parts dodecyl mercaptan, and react at 65°C for 7 hours.

[0047] S3: Heat to 80℃, add butyl acrylate (10 parts each time) and benzoyl peroxide (0.8 parts each time) in three portions, reacting for 1.5 hours each time to obtain the modified synthesis solution.

[0048] The coating process for the non-silicone release agent in this embodiment is as follows:

[0049] (1) Coating liquid formulation: 8 parts of non-silicone release agent, 1 part of composite curing agent (p-toluenesulfonic acid: phosphoric acid = 4:1, diluted to 25% isopropanol solution), and 45 parts of composite solvent.

[0050] (2) Coating was performed on a PET substrate (25μm) using a microgravure coating machine, with a coating amount of 0.2g / m². 2 Cur at 110℃ for 2 minutes.

[0051] Example 3

[0052] This embodiment provides a high-performance non-silicone release agent for battery tapes, comprising the following components by weight: 6 parts modified synthetic liquid, 6 parts amino resin, 4 parts functional diluent, 7 parts composite solvent, and 0.4 parts nano-silica (70nm particle size, KH-550 modified). The amino resin comprises 303LF and melamine-formaldehyde resin (in a 2:1 ratio), the functional diluent comprises 1,4-cyclohexanediethanol and trimethylolpropane (in a 3:1 ratio), and the composite solvent comprises butanone, isopropanol, and ethyl acetate (in a 1:1:1 ratio).

[0053] The preparation method of the non-silicone release agent in this embodiment is as follows: stir the above components at 40°C and 500 rpm for 30 minutes to obtain a liquid non-silicone release agent.

[0054] In this embodiment, the method for synthesizing the modified synthetic solution includes the following steps:

[0055] S1: 480 parts butyl acrylate, 15 parts trifluoroethyl methacrylate and 110 parts butanone-ethanol mixed solvent (1:1) are purged with nitrogen for 25 minutes to remove oxygen, and then heated to 70°C and held for 30 minutes.

[0056] S2: Add 85 parts dodecyl acrylate, 22 parts hydroxyethyl methacrylate, 22 parts butyl acrylate, 5 parts benzoyl peroxide, and 1 part dodecyl mercaptan, and react at 75°C for 5 hours.

[0057] S3: Heat to 90℃, add butyl acrylate (15 parts each time) and benzoyl peroxide (1.2 parts each time) in three batches, react for 1 hour each time, and obtain the modified synthesis solution.

[0058] The coating process for the non-silicone release agent in this embodiment is as follows:

[0059] (1) Coating liquid formulation: 12 parts of non-silicone release agent, 2 parts of composite curing agent (p-toluenesulfonic acid: phosphoric acid = 4:1, diluted to 25% isopropanol solution), and 55 parts of composite solvent.

[0060] (2) Coating was performed on a PET substrate (25μm) using a microgravure coating machine, with a coating amount of 0.6g / m². 2Cur at 115℃ for 1.5 minutes.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Example 1 is that the fluorine-containing monomers were removed from the modified synthesis solution, and the amount of butyl acrylate was increased to 462 parts.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that nano-silica is removed from the non-silicone release agent formulation, and the composite solvent is increased to 10.3 parts.

[0065] Comparative Example 3

[0066] The difference between Comparative Example 3 and Example 1 is that the modified synthesis liquid adopts a one-step polymerization process, that is, all monomers, initiators and chain transfer agents are added to the reactor at one time and reacted at 70°C for 8 hours.

[0067] Performance testing

[0068] The coatings of Examples 1-3 and Comparative Examples 1-3 were tested, wherein:

[0069] 1. Standard for release force and residual adhesion testing: GB / T 25256-2010 "Test Method for 180° Peel Force and Residual Adhesion of Optical Functional Film Release Film";

[0070] 2. Electrolyte resistance test method:

[0071] Test solution: Ethylene carbonate (EC): Dimethyl carbonate (DMC) = 1:1 (volume ratio) mixed solution;

[0072] Test Procedure: Prepare the same sample as for the release force test. Immerse the sample completely in the 40℃ electrolyte solution for 72 hours. After removal, clean the surface with anhydrous ethanol to remove residual electrolyte, and dry at room temperature for 2 hours. Test the release force after immersion using the above release force test method, and calculate the release force retention rate.

[0073] Release force retention rate = Release force before immersion / Release force after immersion × 100%.

[0074] 3. Surface energy testing methods:

[0075] The testing instrument is a contact angle measuring instrument. DSA100;

[0076] Test steps:

[0077] (1) Place the sample on a horizontal test platform and keep the surface clean and dry.

[0078] (2) Add 3 μL of deionized water and diiodomethane to the release layer surface respectively, and measure the static contact angle.

[0079] (3) Each sample was tested 5 times at different locations, and the average value was taken.

[0080] (4) Calculate the surface energy and its polar and dispersive components according to the Owens-Wendt-Rabel-Kaelble method.

[0081] The test results are shown in Table 1.

[0082] Table 1

[0083]

[0084]

[0085] As shown in Table 1, in Examples 1 and 3, the release force can be controlled by adjusting the proportion of amino resin, thus covering medium to high release force requirements and suitable for battery tapes with different viscosities. In Example 2, low release force characteristics are obtained by increasing the proportion of diluent and reducing the content of amino resin, thus meeting the needs of scenarios requiring low peel force, such as automatic labeling. In Comparative Examples 1-3, the release force is high and uncontrollable when there is no fluorinated monomer or one-step polymerization is used, indicating the key role of fluorinated monomer in reducing surface energy and adjusting release force.

[0086] In Examples 1-3, the stepwise polymerization process resulted in a narrower polymer molecular weight distribution (PDI ≤ 1.8), and the use of melamine-formaldehyde resin increased the crosslinking density. Consequently, the release force fluctuation at high temperatures was significantly lower than in Comparative Example 3. In Comparative Example 3, one-step polymerization led to a wider molecular weight distribution (PDI = 2.5), which resulted in easier relaxation of the molecular chains at high temperatures and the greatest release force fluctuation. This demonstrates the importance of stepwise polymerization for heat resistance stability.

[0087] In Examples 1-3, the fluorine groups introduced by the fluorinated monomer (trifluoroethyl methacrylate) reduce the surface energy (18-22 mN / m), forming a physical barrier with nano-silica, significantly inhibiting electrolyte penetration, with minimal change in release force. In Comparative Example 1, without the fluorinated monomer, the surface energy rises to 32 mN / m, making it easier for the electrolyte to wet the release layer, resulting in a significant increase in release force and rendering it unusable. In Comparative Example 2, without the nano-additive, the density of the release layer decreases, and electrolyte penetration intensifies, indicating that nano-silica has a synergistic effect on improving chemical resistance.

[0088] Finally, in Examples 1-3, through the optimization of the compatibility between the release layer and the adhesive layer of the tape, there is less adhesive residue after peeling and the adhesion retention rate is high, which meets the requirements for repeated pasting of battery tape. In Comparative Examples 1-3, without fluorinated monomers or nano-additives, there are more defects on the surface of the release layer, the adhesive residue increases, resulting in a decrease in residual adhesion and affecting the secondary use of the tape.

[0089] The embodiments described above are merely preferred embodiments for fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A non-silicone release agent for high-performance battery tape, characterized in that, It includes the following components by weight: 4-6 parts modified synthetic liquid, 2-6 parts amino resin, 4-9 parts functional diluent, 7-12 parts composite solvent, and 0.1-0.5 parts nano-additives; The preparation method of the modified synthetic liquid includes the following steps: S1. Mix the first monomer, the fluorinated monomer and the butanone-ethanol mixed solvent evenly, purge with nitrogen to remove oxygen, and then heat to 60-70℃ and maintain for 30-50 minutes. S2. Add the second monomer, initiator and chain transfer agent to the mixture obtained in step S1, and then react at 65-75°C for 5-7 hours; S3. Heat the mixture obtained in step S2 to 80-90°C, and then add the first monomer and initiator in three batches, each reaction lasting 1-1.5 hours, to obtain the modified synthetic solution.

2. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, In step S1, the first monomer is butyl acrylate, and the amount added is 420-480 parts; the fluorinated monomer is trifluoroethyl methacrylate, and the amount added is 10-15 parts; the amount added is 90-110 parts of the butanone-ethanol mixed solvent.

3. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, In step S2, the second monomer comprises: 65-85 parts of dodecyl acrylate, 18-22 parts of hydroxyethyl methacrylate, and 18-22 parts of butyl acrylate.

4. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, In step S2, the initiator is benzoyl peroxide, and the amount added is 3 to 5 parts; the chain transfer agent is dodecyl mercaptan, and the amount added is 0.5 to 1 part.

5. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, In step S3, the first monomer added each time is 10 to 15 parts, and the initiator is 0.8 to 1.2 parts.

6. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, The nano-additive is nano-silica with a surface modified by a silane coupling agent and a particle size of 50-100 nm; the amino resin is a mixture of amino resin 303LF and melamine-formaldehyde resin in a mass ratio of 3:

1.

7. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, The functional diluent is a mixture of 1,4-cyclohexanediethanol and trimethylolpropane in a mass ratio of 4:

1.

8. The non-silicone release agent for high-performance battery tape according to claim 1, characterized in that, The composite solvent is a mixture of butanone, isopropanol and ethyl acetate in a mass ratio of 2:2:

1.

9. A method for preparing a non-silicone release agent for high-performance battery tape according to any one of claims 1 to 8, characterized in that, The process involves mixing the modified synthetic liquid, amino resin, functional diluent, composite solvent, and nano-additives in the specified amounts at 30–40°C for 30–40 minutes with a stirring speed of 300–500 rpm to obtain a non-silicone release agent for battery tapes.

10. A method for applying a non-silicone release agent for high-performance battery tape according to any one of claims 1 to 8, characterized in that, include: Mix 8-12 parts of high-performance battery tape with a non-silicone release agent, 1-2 parts of a composite curing agent, and 45-55 parts of a composite solvent to obtain a coating liquid; apply the coating liquid to the surface of the substrate and cure it at 110-115°C for 1.5-2 minutes to obtain a release layer. The composite curing agent is obtained by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 4:1, and then mixing it with isopropanol in a mass ratio of (20-30):(70-80).

Images