A high-temperature-resistant light-release-force release agent for a battery, a release film, and a preparation method

Abstract

The application discloses a high-temperature-resistant and light-release-force release agent for a battery, and the main components of the release agent are a first hydroxyl-containing acrylic resin, a second hydroxyl-containing acrylic resin, an active diluent, a curing agent, a catalyst and a solvent; the first hydroxyl-containing acrylic resin comprises a first polymerized monomer and a high-temperature-resistant monomer; the second hydroxyl-containing acrylic resin comprises a second polymerized monomer and modified cellulose nanocrystals; the first polymerized monomer and the second polymerized monomer both contain a functional monomer, hydroxyethyl methacrylate and / or hydroxyethyl acrylate; the active diluent is a branched polyester dihydric alcohol; and the mass ratio of the first hydroxyl-containing acrylic resin to the second hydroxyl-containing acrylic resin is (2-13):1. The release agent contains different high-temperature-resistant substances and different branched structures through the first hydroxyl-containing acrylic resin and the second hydroxyl-containing acrylic resin, the proportion of the two is adjusted, the active diluent is combined, the cross-linking structure of the release layer is controlled, and then the high-temperature resistance of the release layer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of release film preparation, in particular to a high-temperature-resistant light-release-force release agent for batteries, a release film and a preparation method. BACKGROUND

[0002] Release film refers to a functional film with low surface energy obtained by coating a chemical coating on a film and drying or ultraviolet curing. Among the release agents required for release film, the release agent using a main agent of silicone oil has many outstanding advantages, such as good transparency, flexible adjustment of release force, etc. At present, electronic products are increasingly high-end and increasingly demanding. Electronic products must be protected by easy-to-peel protective films, i.e. release films, during processing. However, electronic products are extremely sensitive to silicon elements. The release film obtained by coating the existing silicone oil release agent is prone to silicon migration, and the migrated silicon elements are prone to cause electronic product processing defects and short circuit risks; the residual adhesion rate is low, and the release film is not heat-resistant, resulting in a decrease in the adhesion of the release film and a loss of protection.

[0003] Therefore, it is necessary to improve the existing release film. SUMMARY

[0004] One of the purposes of the present application is to overcome the defects in the prior art and provide a high-temperature-resistant light-release-force release agent for batteries. By containing different high-temperature-resistant substances and different branched structures in the first and second hydroxyl-containing acrylic resins, adjusting the proportion of the two, and combining with the active diluent, the cross-linking structure of the release layer is controlled, and the high-temperature resistance of the release layer is improved.

[0005] In order to achieve the above process effect, the technical scheme of the present application is as follows: a high-temperature-resistant light-release-force release agent for batteries, the main components of the release agent are a first hydroxyl-containing acrylic resin, a second hydroxyl-containing acrylic resin, an active diluent, a curing agent, a catalyst and a solvent;

[0006] The first hydroxyl-containing acrylic resin comprises a first polymerized monomer and a high-temperature-resistant monomer;

[0007] The second hydroxyl-containing acrylic resin comprises a second polymerized monomer and a modified cellulose nanocrystal;

[0008] The first polymerized monomer and the second polymerized monomer both contain a functional monomer of hydroxyethyl methacrylate and / or hydroxyethyl acrylate;

[0009] The active diluent is a branched polyester diol;

[0010] The mass ratio of the first hydroxyl-containing acrylic resin to the second hydroxyl-containing acrylic resin is (2-13): 1.

[0011] The preferred technical solution is as follows: by mass parts, the main components of the release agent are 9-12 parts of the first hydroxyl-containing acrylic resin, 1-3 parts of the second hydroxyl-containing acrylic resin, 10-15 parts of the reactive diluent, 1-1.5 parts of the curing agent, 0.3-1 parts of the catalyst, and 100-200 parts of the solvent.

[0012] The preferred technical solution is that the modifier of the modified cellulose nanocrystals is γ-methacryloyloxypropyltrimethoxysilane.

[0013] The preferred technical solution is as follows: the first polymeric monomer further includes a hard monomer, a soft monomer and a viscosity-reducing monomer, and the mass ratio of the hard monomer, soft monomer, functional monomer, viscosity-reducing monomer and high-temperature resistant monomer is (6-10):(60-70):(10-16):(5-8):(3-6).

[0014] A preferred technical solution is that the second polymeric monomer further includes an endogenous monomer and a viscous monomer, wherein the mass ratio of the endogenous monomer, the viscous monomer, the functional monomer and the modified cellulose nanocrystals is (4-6):(60-70):(2-6):(0.5-0.8).

[0015] The preferred technical solution is as follows: the viscosity-reducing monomer is glycidyl tert-carbonate and / or isobornyl methacrylate, the hard monomer is methyl methacrylate, the soft monomer is isooctyl acrylate and butyl acrylate, the functional monomer of the first polymerizing monomer also includes acrylic acid, and the high-temperature resistant monomer includes 1-vinyl-2-pyrrolidone and / or 4-acryloylmorpholine.

[0016] The comonomer is methyl methacrylate, the viscous monomer is isooctyl acrylate and butyl acrylate, and the functional monomer of the second polymerizing monomer also includes acrylic acid.

[0017] A preferred technical solution is that the curing agent is an aliphatic isocyanate, and the catalyst is dibutyltin dilaurate and p-toluenesulfonic acid. Further, by mass parts, the release agent contains 100 parts of hydroxyl acrylic resin, 0.5-1 parts of dibutyltin dilaurate, and 2-5 parts of p-toluenesulfonic acid.

[0018] The preferred technical solution is that the solvent includes toluene, butanone, and n-heptane, and the mass ratio of toluene, butanone, and n-heptane is (1-2):(4-6):(1-2).

[0019] The second objective of this invention is to overcome the deficiencies in the prior art and provide a high-temperature resistant, low-release-force release film, comprising a substrate layer and a release layer, wherein the release layer is made from the aforementioned high-temperature resistant, low-release-force release agent.

[0020] The third objective of this invention is to overcome the deficiencies in the prior art and provide a method for preparing a high-temperature resistant, light-release-force release film, comprising the following steps:

[0021] S1: Configuring the substrate layer and the above-mentioned high-temperature resistant, light-release-force release agent;

[0022] S2: The high-temperature resistant, low-release-force release agent is applied to the surface of the substrate layer to obtain an uncured release layer;

[0023] S3: Dry and cure the release layer. The continuous drying temperatures are set sequentially as follows: 70±5℃, 95±5℃, 110±5℃, 120±5℃, 130±5℃, 95±5℃.

[0024] S4: Wind up to obtain release film;

[0025] The thickness of the release layer after curing is 0.2–1 μm.

[0026] The advantages and beneficial effects of this invention are as follows:

[0027] The battery uses a high-temperature resistant, low-release-force release agent. By adjusting the ratio of the first and second hydroxyl-containing acrylic resins containing different high-temperature resistant materials and different branched structures, and combining them with an active diluent, the cross-linking structure of the release layer is controlled, thereby improving the high-temperature resistance of the release layer. Detailed Implementation

[0028] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0029] First hydroxyl-containing acrylic resin

[0030] It includes hard monomers, soft monomers, functional monomers, viscosity-reducing monomers and high-temperature resistant monomers, with the mass ratio of hard monomers, soft monomers, functional monomers, viscosity-reducing monomers and high-temperature resistant monomers being (6-10): (60-70): (10-16): (5-8): (3-6).

[0031] The hard monomer is methyl methacrylate. The soft monomers are isooctyl acrylate and butyl acrylate. The first hydroxyl-containing acrylic resin obtained from isooctyl acrylate and butyl acrylate monomers exhibits high initial tack and low release force after film formation. Further, the mass ratio of isooctyl acrylate to butyl acrylate is (1-2):1. The functional monomer is hydroxyethyl methacrylate and acrylic acid, or hydroxyethyl acrylate and acrylic acid. Further, the mass ratio of acrylic acid and hydroxyethyl acrylate is (5-10):1. Even further, the mass ratio of acrylic acid and hydroxyethyl acrylate is (6-9):1. The viscosity-reducing monomer is glycidyl tert-carbonate and / or isobornyl methacrylate. Further, the mass ratio of glycidyl tert-carbonate and isobornyl methacrylate is (1.5-3):1. Even further, the mass ratio of glycidyl tert-carbonate and isobornyl methacrylate is (1.8-2.5):1. Glycidyl tert-carbonate contains three alkyl substituents, providing significant steric hindrance to prevent entanglement of the first hydroxyl-containing acrylic resin segments. It also contains hydroxyl groups that react with the carboxyl groups of acrylic acid to release hydroxyl groups, further interacting with the second hydroxyl-containing acrylic resin and the curing agent to increase the crosslinking density of the release layer. Isobornyl methacrylate provides significant steric hindrance to further prevent entanglement of the first hydroxyl-containing acrylic resin segments, and can also improve the flexibility and impact strength of the polymer to a certain extent. After film formation, it improves the hardness, heat resistance, abrasion resistance, and shrinkage resistance of the release layer. High-temperature resistant monomers include 1-vinyl-2-pyrrolidone and / or 4-acryloylmorpholine. 1-Vinyl-2-pyrrolidone has a significant steric hindrance effect; it can be added to the polymer as a flexible segment, thereby improving the hardness and toughness of the first hydroxyl-containing acrylic resin, and improving the low-temperature performance and impact resistance of the material. Containing vinyl functional groups, it can react with the double bonds of other monomers, covalently binding into the polymer chain, enhancing the internal crosslinking degree of the material, and improving the heat resistance and solvent resistance of the release layer. 4-Acryloylmorpholine contains an acryloyl group, an active monomer that can undergo free radical polymerization with other monomers, thereby enhancing the internal crosslinking density and structure of the material, and improving its mechanical strength, heat resistance, chemical resistance and water resistance. Among them, the morpholine group gives the copolymer good flexibility, effectively regulating the balance between the hardness and toughness of the release layer, and also improving the tensile strength, tear strength and resistance to environmental stress of the release layer.

[0032] The preparation of the first hydroxyl-containing acrylic resin involves the following steps: First, glycidyl tert-carbonate acrylic acid, acrylic acid, and methyl methacrylate undergo epoxy ring-opening and carbon-carbon double bond copolymerization in a solvent. Under the action of a first initiator, the reaction temperature is 70–75°C, and the first initiator is added slowly dropwise over 1 hour, followed by a 1-hour incubation period. Next, isooctyl acrylate and butyl acrylate soft monomers, hydroxyethyl acrylate functional monomers, isobornyl methacrylate viscosity-reducing monomers, 1-vinyl-2-pyrrolidone, and / or 4-acryloylmorpholine high-temperature resistant monomers are added. Under the action of a second initiator, the reaction temperature is 76–82°C, and the second initiator is added slowly dropwise over 3 hours, followed by a 1-hour incubation period. Finally, the remaining initiator is added slowly dropwise over 0.3 hours, followed by a 1-hour incubation period. The stepwise addition of the viscosity-reducing monomers not only controls the polymer viscosity but also optimizes the position of sterically hindered groups in the polymer molecular chain, resulting in a more uniform distribution of reactive groups, improved release agent dispersibility, and easier further crosslinking, thus optimizing the crosslinking density.

[0033] The initiator of the first hydroxyl-containing acrylic resin is a peroxide. More specifically, the peroxide is di-tert-pentyl peroxide and benzoyl peroxide (BPO). Even further, the mass ratio of di-tert-pentyl peroxide to benzoyl peroxide is 1:(0.6–1.2). The mass ratio of di-tert-pentyl peroxide to benzoyl peroxide can be 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, or 1:1.2, or any two of these ratios can be used as a range between the maximum and minimum values. Di-tert-pentyl peroxide readily forms a linear structure in the first hydroxyl-containing acrylic resin, and benzoyl peroxide has a high conversion rate for monomers. The combination of these two components results in a narrow molecular weight distribution for the first hydroxyl-containing acrylic resin.

[0034] Based on the amount of the first hydroxyl-containing acrylic resin monomer, after the esterification of glycidyl tert-carbonate with acrylic acid and acrylic acid, the acrylic acid is in excess, and the carboxyl groups are still retained. Therefore, the hydroxyl and carboxyl active groups on the side chains of the first hydroxyl-containing acrylic resin are extended, resulting in better hydrophilicity, more uniform distribution in the diluted release agent, and easier crosslinking with branched polyester diol and the second hydroxyl-containing acrylic resin. After film formation, a release layer with a thin layer and light release force is formed.

[0035] Second hydroxyl-containing acrylic resin

[0036] It includes cohesive monomers, viscous monomers, functional monomers and modified cellulose nanocrystals, with the mass ratio of cohesive monomers, viscous monomers, functional monomers and modified cellulose nanocrystals being (4-6):(60-70):(2-6):(0.5-0.8).

[0037] The tackifying monomers are isooctyl acrylate and butyl acrylate. The second hydroxyl-containing acrylic resin obtained from isooctyl acrylate and butyl acrylate monomers exhibits high initial tack and low release force after film formation. Further, the mass ratio of isooctyl acrylate to butyl acrylate is (2-4):1. The functional monomers are hydroxyethyl methacrylate and acrylic acid, or hydroxyethyl acrylate and acrylic acid. Further, the mass ratio of acrylic acid to hydroxyethyl methacrylate is (3-7):1. Even further, the mass ratio of acrylic acid to hydroxyethyl methacrylate is (4-6):1.

[0038] Modification method of cellulose nanocrystals: First, microcrystalline cellulose is treated with concentrated sulfuric acid to obtain cellulose nanocrystals, which are then modified with γ-methacryloxypropyltrimethoxysilane (KH570 silane coupling agent). Specifically, concentrated sulfuric acid is first diluted to 70% and mixed with microcrystalline cellulose at a mass ratio of 20:1. In a reactor, the water bath temperature is 60±1℃, and the reaction time is maintained for 3 hours. The resulting product is washed with deionized water until neutral and then dried to a moisture content of less than 1.0%. The acid-hydrolyzed microcrystalline cellulose is then prepared into a 2% suspension with distilled water. The suspension is ultrasonically treated with an ultrasonic cell disruptor at 8000 rpm for 10 minutes. After multiple dialysis cycles, the suspension is freeze-dried to obtain nanocrystalline cellulose. Furthermore, nanocrystalline cellulose is dissolved in an ethanol solution, and the pH is adjusted to a weakly acidic level (6.4–6.8) using glacial acetic acid and stirred for 1 hour. Then, KH570 is added at a mass ratio of 1:(1.5–2) to nanocrystalline cellulose. If too much KH570 is added, it will be introduced into the release agent, which may easily lead to silicon transfer. If too little KH570 is added, the cellulose nanocrystals may be unevenly dispersed and agglomerated during the preparation of the second hydroxyl-containing acrylic resin, which will negatively affect the high-temperature resistance of the release layer prepared by the second hydroxyl-containing acrylic resin.

[0039] Nanocellulose prepared by the sulfuric acid method carries sulfonate groups on its surface, which have a high charge and optimize the antistatic effect of the release film, preventing the formation of static stains and the adsorption of particulate dust in the air, thus affecting the application of the release film in electronic products.

[0040] The preparation of the second hydroxyl-containing acrylic resin involves the following steps: First, a first portion of modified cellulose nanocrystals, methyl methacrylate, and hydroxyethyl methacrylate undergo a carbon-carbon double bond copolymerization reaction in a solvent. Under the action of a first initiator, the reaction temperature is 70–75°C, and the first initiator is added slowly dropwise over 1 hour, followed by a 1-hour incubation period. Next, isooctyl acrylate and butyl acrylate soft monomers, a second portion of modified cellulose nanocrystals, and acrylic functional monomers are added. Under the action of a second initiator, the reaction temperature is 76–82°C, and the second initiator is added slowly dropwise over 3 hours, followed by a 1-hour incubation period. Finally, the remaining initiator is added slowly dropwise over 0.3 hours, followed by a 1-hour incubation period. The stepwise addition of the modified cellulose nanocrystal components not only controls the polymer viscosity but also optimizes the position of sterically hindered groups in the polymer molecular chain, resulting in a uniform distribution of reactive groups, improved release agent dispersibility, and facilitates further crosslinking, thus optimizing the crosslinking density. Furthermore, the amount of the first modified cellulose nanocrystal added is 40% to 50% of the total mass of the modified cellulose nanocrystal.

[0041] The initiator for the second hydroxyl-containing acrylic resin is benzoyl peroxide (BPO). Benzoyl peroxide has a high conversion rate for monomers, and the molecular weight distribution of the second hydroxyl-containing acrylic resin obtained by combining the first modified cellulose nanocrystal addition step is narrow.

[0042] Reactive diluent

[0043] The product is a branched polyester diol, which is formed by the condensation polymerization of a polyacid and a polyol. The polyacid is succinic anhydride, and the polyol is propylene oxide. Succinic anhydride and propylene oxide are mixed in a molar ratio of 1:2 and reacted at a constant temperature of 78°C for 3 hours using a cocatalyst of 1,3-diisopropyl-2-thiourea in a molar ratio of 1:1 and a main catalyst of 1,8-diazabicyclo[5.4.0]undec-7-ene DBU in a molar ratio of 1:1 to obtain a linear alternating copolyester. The molecular weight of the polyester diol is controlled by using water as a chain transfer agent.

[0044] Aliphatic isocyanates

[0045] Improve the weather resistance of the release film; cross-linking with a catalyst improves the hardness and smoothness of the release layer, while achieving an ultra-thin release layer. The choice of curing agent determines the curing rate of the release layer; too fast a curing rate will not yield a uniform film; too slow a curing rate will affect production efficiency and film performance.

[0046] p-Toluenesulfonic acid

[0047] p-Toluenesulfonic acid protons (H atoms) add to the carboxyl oxygen atom of acrylic acid in both the first and second hydroxyl-containing acrylic resins, nucleophilically attacking the hydroxyl groups of the branched polyester diol and the hydroxyl groups in both resins, leading to dehydration and esterification. Because the polyester diol is a linear alternating copolyester with low steric hindrance, it more easily combines with the carboxyl groups of acrylic acid in both resins via p-toluenesulfonic acid to form a cross-linked release layer, improving the toughness and hardness of the release film.

[0048] The composition of the first hydroxyl-containing acrylic resin, by mass parts, is shown in Table 1 below:

[0049]

[0050] In the preparation of the first hydroxyl-containing acrylic resin, the amount of the first initiator added is 10% of the total initiator mass, and the amount of the second initiator added is 23% of the total initiator mass.

[0051] The composition of the second hydroxyl-containing acrylic resin, by mass parts, is shown in Table 2 below:

[0052]

[0053] In the preparation of the second hydroxyl-containing acrylic resin, the amount of the first modified cellulose nanocrystal added is 44% of the total mass of the modified cellulose nanocrystal. The amount of the first initiator added is 10% of the total initiator mass, and the amount of the second initiator added is 30% of the total initiator mass.

[0054] The composition of the release agent by mass parts is shown in Table 3 below:

[0055]

[0056] The mass ratio of toluene, butanone, and n-heptane is 1.5:5:1.5.

[0057] A method for preparing a high-temperature resistant, low-release-force release film for batteries includes the following steps:

[0058] S1: Configuring a substrate layer and a high-temperature resistant, low-release-force release agent for batteries, configured according to Table 3;

[0059] S2: High-temperature resistant, low-release-force release agent is applied to the surface of a substrate layer with a thickness of 50μm using a 200-line oblique micro-grooving roller at a speed of 40m / min to obtain an uncured release layer.

[0060] S3: Dry and cure the release layer. The continuous drying temperatures are set to 70℃, 95℃, 110℃, 120℃, 130℃, and 95℃ in sequence. The thickness of the cured release layer is 0.3μm.

[0061] S4: Rewind to obtain the release film.

[0062] Performance testing

[0063] (1) Residual adhesion rate: The residual adhesion rate was tested using Nitto 31B tape;

[0064] (2) Peel force: After applying Nitto 31B tape for 20 minutes, a tensile test was conducted (the force value detected at a peeling speed of 300 mm / min at a 180° angle).

[0065] (3) High temperature resistance: Clean the stainless steel plate, and evenly apply a 25mm*100mm release film sample to the stainless steel plate. Place it in an oven and bake at 120℃ for 30 minutes. Remove it and cool it to room temperature. Then slowly peel off the release film and observe the surface condition of the stainless steel plate, mainly observing the deformation of the release film and the amount of residual adhesive. Test the changes of the release film at 150℃ using the same method.

[0066] The method for classifying residual adhesive is as follows: the grades are divided into four levels: A, B, C, and D. Grade A: no residue; Grade B: residual area accounts for 1% to 5% of the total area of ​​the release film sample; Grade C: residual area accounts for 6% to 30% of the total area of ​​the release film sample; Grade D: residual area accounts for more than 31% of the total area of ​​the release film sample.

[0067] The performance test results of the examples and comparative examples are shown in Table 4 below:

[0068]

[0069] Silicone oil release films are made by curing silicone oil as the main agent. Usually, the residual adhesion rate is less than 90%, and silicone transfer occurs. They are easy to melt in environments above 90°C, which leads to the failure of the release film's function.

[0070] Compared to Example 1, Example 2 increased the amount of the second hydroxyl-containing acrylic resin. Although this improved the high-temperature resistance, the increased crosslinking density led to increased hardness of the release layer, which in turn resulted in poor toughness of the release film.

[0071] Compared to Example 1, Example 3 shows a reduction in the amount of the second hydroxyl-containing acrylic resin added, which negatively affects the crosslinking density after curing, and consequently reduces the high-temperature resistance.

[0072] Compared to Example 1, the second hydroxyl-containing acrylic resin in Comparative Example 1 did not contain modified cellulose nanocrystals, which negatively affected its high-temperature resistance.

[0073] Compared to Example 1, Comparative Example 2's first hydroxyl-containing acrylic resin contains modified cellulose nanocrystals as its high-temperature resistant monomer. Since the synthesis of the first hydroxyl-containing acrylic resin contains viscosity-reducing monomers and 1-vinyl-2-pyrrolidone, both of which have steric hindrance, thus controlling the branched structure and viscosity of the first hydroxyl-containing acrylic resin, the addition of modified cellulose nanocrystals makes it difficult to control the viscosity during the synthesis of the first hydroxyl-containing acrylic resin and changes the branched structure of the first hydroxyl-containing acrylic resin. The resulting first hydroxyl-containing acrylic resin has a wide molecular weight distribution, which has a negative impact on the curing crosslinking density and thus a negative impact on the high-temperature resistance.

[0074] Compared to Example 1, Comparative Example 3 did not contain an active diluent in the release agent, which negatively affected the crosslinking density after curing, thus reducing its high-temperature resistance.

[0075] Compared to Example 1, Comparative Example 4 shows that the addition of the second hydroxyl-containing acrylic resin is excessive. With the addition of solvent and reactive diluent remaining unchanged, the viscosity of the release agent will increase, making it easy to apply unevenly. The second hydroxyl-containing acrylic resin has a cross-linked structure, and its increased amount leads to a decrease in the content of the first hydroxyl-containing acrylic resin with a linear structure. This is not conducive to the action of the catalyst and curing agent on the hydroxyl and carboxyl groups in the raw material structure, thus having a negative impact on the curing effect and the curing cross-linking density, and consequently having a negative impact on the mechanical properties and high-temperature resistance of the release layer.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature resistant, low-release-force release agent for batteries, characterized in that, The release agent mainly consists of a first hydroxyl-containing acrylic resin, a second hydroxyl-containing acrylic resin, an active diluent, a curing agent, a catalyst, and a solvent; The first hydroxyl-containing acrylic resin includes a first polymeric monomer and a high-temperature resistant monomer; The second hydroxyl-containing acrylic resin comprises a second polymeric monomer and modified cellulose nanocrystals; Both the first and second monomers contain the functional monomers hydroxyethyl methacrylate and / or hydroxyethyl acrylate; The active diluent is a branched polyester diol; The mass ratio of the first hydroxyl-containing acrylic resin to the second hydroxyl-containing acrylic resin is (2-13):

1.

2. The high-temperature resistant, low-release-force release agent for batteries according to claim 1, characterized in that, The release agent, by mass parts, mainly comprises 9-12 parts of a first hydroxyl-containing acrylic resin, 1-3 parts of a second hydroxyl-containing acrylic resin, 10-15 parts of an active diluent, 1-1.5 parts of a curing agent, 0.3-1 parts of a catalyst, and 100-200 parts of a solvent.

3. The high-temperature resistant, lightweight release agent for batteries according to claim 1 or 2, wherein the modifier of the modified cellulose nanocrystals is γ-methacryloyloxypropyltrimethoxysilane.

4. The high-temperature resistant, low-release-force release agent for batteries according to claim 2, characterized in that, The first polymeric monomer also includes a hard monomer, a soft monomer, and a viscosity-reducing monomer, wherein the mass ratio of the hard monomer, soft monomer, functional monomer, viscosity-reducing monomer, and high-temperature resistant monomer is (6-10):(60-70):(10-16):(5-8):(3-6).

5. The high-temperature resistant, low-release-force release agent for batteries according to claim 3, characterized in that, The second polymeric monomer further includes an endogenous monomer and a viscous monomer, wherein the mass ratio of the endogenous monomer, the viscous monomer, the functional monomer and the modified cellulose nanocrystals is (4-6):(60-70):(2-6):(0.5-0.8).

6. The high-temperature resistant, low-release-force release agent for batteries according to claim 4 or 5, characterized in that, The viscosity-reducing monomer is glycidyl tert-carbonate and / or isobornyl methacrylate, the hard monomer is methyl methacrylate, the soft monomer is isooctyl acrylate and butyl acrylate, the functional monomer of the first polymerizing monomer also includes acrylic acid, and the high-temperature resistant monomer includes 1-vinyl-2-pyrrolidone and / or 4-acryloylmorpholine. The comonomer is methyl methacrylate, the viscous monomer is isooctyl acrylate and butyl acrylate, and the functional monomer of the second polymerizing monomer also includes acrylic acid.

7. The high-temperature resistant, low-release-force release agent for batteries according to claim 6, characterized in that, The curing agent is an aliphatic isocyanate, and the catalyst is dibutyltin dilaurate and p-toluenesulfonic acid.

8. The high-temperature resistant, low-release-force release agent for batteries according to claim 1 or 2, characterized in that, The solvent includes toluene, butanone, and n-heptane, and the mass ratio of toluene, butanone, and n-heptane is (1-2):(4-6):(1-2).

9. A high-temperature resistant, low-release-force release film for batteries, comprising a substrate layer and a release layer, characterized in that, The release layer is made from the high-temperature resistant, low-release-force release agent for batteries as described in any one of claims 1 to 8.

10. A method for preparing a high-temperature resistant, low-release-force release film for batteries, characterized in that, Includes the following steps: S1: Configuring a substrate layer and a high-temperature resistant, lightweight release agent for batteries as described in any one of claims 1 to 8; S2: The high-temperature resistant, low-release-force release agent is applied to the surface of the substrate layer to obtain an uncured release layer; S3: Dry and cure the release layer. The continuous drying temperatures are set sequentially as follows: 70±5℃, 95±5℃, 110±5℃, 120±5℃, 130±5℃, 95±5℃. S4: Wind up to obtain release film; The thickness of the release layer after curing is 0.2–1 μm.

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