High-temperature-resistant UV insulating paint applied to new energy battery and preparation method of high-temperature-resistant UV insulating paint

Abstract

The invention relates to the field of new energy automobile power battery shell protection, and particularly discloses a high-temperature-resistant UV insulating coating applied to a new energy battery and a preparation method of the high-temperature-resistant UV insulating coating. The high-temperature-resistant UV insulating coating applied to the new energy battery is prepared from the following raw materials in parts by mass: 10 to 30 parts of polyurethane modified acrylic resin, 15 to 40 parts of polysilazane modified acrylic resin, 20 to 30 parts of epoxy acrylic resin, 10 to 30 parts of monofunctional acrylic monomer, 10 to 20 parts of bifunctional acrylic monomer and 5 to 10 parts of polyfunctional acrylic monomer, 5-10 parts of a modified polyacrylonitrile copolymer, 1-5 parts of fumed silica, 1-5 parts of a photoinitiator, 1-5 parts of a pigment, 1-5 parts of a dispersant, 1-5 parts of an antifoaming agent and 1-5 parts of a leveling agent; the preparation method comprises the following steps: sequentially adding the raw materials into a stirring kettle, and fully and uniformly stirring. The high-temperature-resistant UV insulating paint applied to the new energy battery has the advantage that the defect that the high-temperature-resistant performance of the UV insulating paint is still insufficient during use can be overcome.

Description

Technical Field

[0001] The present application relates to the field of protection of power battery housings of new energy vehicles, and more specifically, it relates to a high-temperature resistant UV insulating coating applied to new energy batteries and a preparation method thereof. Background Art

[0002] For new energy electric vehicles, the power battery is one of its core components and the power source for the vehicle. Therefore, the power battery must have high safety and long service life. Most of the new energy power batteries on the market are ternary lithium batteries or lithium iron phosphate batteries. The energy density of a single battery is large and they are closely arranged in the battery pack. When short-circuited, they can instantly generate high temperature and high pressure to cause spontaneous combustion. Therefore, it is necessary to perform insulation protection treatment on the outer shell surface of the power battery to prevent the battery from short-circuiting, prevent the internal oxidation of the battery from releasing flammable gases, and prevent the battery shell from being corroded and damaged by external water vapor and corrosive chemicals.

[0003] The insulation protection of the power battery shell of new energy vehicles on the market currently uses a PET (polyethylene terephthalate) single-sided acrylic pressure-sensitive tape to cover the battery shell for insulation protection, which can also be called a blue film. The blue film has a low bonding strength to the battery shell, and is prone to shrinkage, debonding, and cohesive failure in high temperature and high humidity environments, so the insulation protection will fail and cause safety hazards. With the development of high-voltage fast charging technology for new energy vehicles, the blue film can no longer meet the requirements for insulation protection of the battery shell.

[0004] At present, relevant patents disclose a UV insulating coating to replace blue film for battery insulation protection. UV insulating coating is generally composed of acrylic resin, acrylic monomer, additives, initiator, etc. Compared with blue film, it has stronger bonding strength and insulation performance. However, there are some problems in the current use of UV insulating coating. When new energy vehicles are charging or driving, accidents often cause spontaneous combustion. The temperature of the battery shell is too high, causing the insulating coating to carbonize or powderize, resulting in insulation protection failure, accelerating spontaneous combustion, and shortening the escape time of personnel. Although the addition of inorganic fillers can improve high temperature resistance, the resin matrix in the paint film will turn yellow and peel off at high temperatures, and the high temperature resistance problem cannot be solved. Summary of the invention

[0005] In order to improve the defect that the high temperature resistance of UV insulating coatings is still insufficient during use, the present application provides a high temperature resistant UV insulating coating for use in new energy batteries and a preparation method thereof.

[0006] In the first aspect, the present application provides a high temperature resistant UV insulating coating for new energy batteries, which adopts the following technical solution: A high-temperature-resistant UV insulating coating for new energy batteries comprises the following raw materials in parts by mass: 10-30 parts of polyurethane-modified acrylic resin, 15-40 parts of polysilazane-modified acrylic resin, 20-30 parts of epoxy acrylic resin, 10-30 parts of monofunctional acrylic monomer, 10-20 parts of difunctional acrylic monomer, 5-10 parts of multifunctional acrylic monomer, 5-10 parts of modified polyacrylonitrile copolymer, 1-5 parts of fumed silica, 1-5 parts of photoinitiator, 1-5 parts of pigment, 1-5 parts of dispersant, 1-5 parts of defoamer and 1-5 parts of leveling agent.

[0007] By adopting the above technical scheme, since the high-temperature resistant insulating coating used is mainly composed of polyurethane-modified acrylic resin and polysilazane-modified acrylic resin, the carbamate polar groups and polyol polyether soft segment groups in the polyurethane have excellent adhesion and flexibility on the metal substrate, but the high-temperature resistance is general. The silicon and nitrogen atoms in the polysilazane-modified acrylate are connected by covalent chemical bonds as the main chain, and acrylic acid modification is performed at its end to make it have photocurable properties. The polysilazane-modified acrylic resin gives the polysilazane photocurable properties and is compatible with other acrylic photocurable monomers and resins.

[0008] Polysilazane contains three elements: silicon, nitrogen and carbon. The silicon-nitrogen bond is a strong polar group with excellent adhesion to metal substrates. After 1400°C, the silicon, nitrogen and carbon in the polysilazane resin will be converted into silicon carbide oxide and silicon carbide nitride. Silicon carbide oxide and silicon carbide nitride have excellent high temperature resistance, which can reach above 1800°C. At the same time, they have excellent adhesion and excellent insulation to metal substrates. By adjusting the functionality and viscosity of different polysilazane-modified acrylic resins, in combination with polyurethane-modified acrylic resins, epoxy acrylic resins and acrylic monomers, UV insulating coatings with excellent high temperature resistance can be achieved.

[0009] Preferably, the polyurethane modified acrylic resin is one or a combination of difunctional polyurethane modified acrylic resin, trifunctional polyurethane modified acrylic resin, tetrafunctional polyurethane modified acrylic resin, pentafunctional polyurethane modified acrylic resin, and hexafunctional polyurethane modified acrylic resin.

[0010] Since the multifunctional polyurethane modified acrylic resin is a polyurethane modified acrylic resin with multiple functionalities, and the molecules of the multifunctional polyurethane modified acrylic resin contain acrylic functional groups and urethane bonds, compared with monofunctional resins, the multifunctional polyurethane modified acrylic resin solves the problems of slow curing speed and low hardness of the coating. Preferably, the functionality of the polysilazane-modified acrylic resin is one or a combination of difunctional polysilazane-modified acrylic resin, trifunctional polysilazane-modified acrylic resin, and tetrafunctional polysilazane-modified acrylic resin.

[0011] Multifunctional polysilazane-modified acrylic resin is a material that improves performance by combining polysilazane with acrylic resin. Since acrylic resin is polymerized from acrylic acid, methacrylic acid and their derivatives, these monomers form a stable molecular chain structure during the polymerization process. This structure enables the acrylic resin to withstand a certain high temperature environment and is not prone to thermal decomposition or combustion. Polysilazane is a polymer with silicon-nitrogen as a repeating main chain, which can be converted into silicon carbide oxide and silicon carbide nitride under high temperature conditions. Therefore, the introduction of polysilazane can further improve the overall high temperature resistance.

[0012] Preferably, the viscosity of the polysilazane-modified acrylic resin is 5000-80000 mPa·s.

[0013] Preferably, the viscosity of the polysilazane-modified acrylic resin is selected from any value of 5000, 6000, 8000, 10000, 20000, 50000, 80000 mPa·s or a range between any values.

[0014] Preferably, the polysilazane structure of the polysilazane-modified acrylic resin is one or a combination of linear polysilazane and cyclic polysilazane.

[0015] Since the silicon-nitrogen bond contained in linear polysilazane and cyclic polysilazane is a very stable covalent bond with a high bond energy, it can remain stable under high temperature conditions, so that it can be converted into silicon carbide oxide and silicon carbide nitride under high temperature conditions. Silicon carbide oxide and silicon carbide nitride have higher high temperature resistance, thereby further improving the high temperature resistance of the overall coating.

[0016] Preferably, the content of linear polysilazane in the polysilazane-modified acrylic resin is 20%-50%, and the content of cyclic polysilazane is 50%-80%.

[0017] Preferably, the epoxy acrylic resin is one or a combination of monofunctional epoxy acrylic resin, difunctional epoxy acrylic resin and trifunctional epoxy acrylic resin.

[0018] Since epoxy acrylic resin can form a three-dimensional network structure during the curing process, this structure is conducive to increasing the intermolecular force, so that the resin can still maintain structural stability at high temperatures and is not easy to soften or degrade. At the same time, epoxy acrylic resin is a thermosetting resin and is not easy to melt or soften again, which makes epoxy acrylic resin have excellent high temperature resistance in high temperature environments. The molecular structure and chemical properties of epoxy acrylic resin are stable, making it difficult to change due to environmental factors, thereby maintaining excellent insulation properties.

[0019] Preferably, the monofunctional acrylic monomer is one or a combination of tetrahydrofuran acrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, isobornyl acrylate, isobornyl methacrylate, acryloylmorpholine, dicyclopentene acrylate, cyclotrimethylolpropane formal acrylate, and ethoxylated phenoxy acrylate.

[0020] Preferably, the bifunctional acrylic monomer is one or a combination of 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, ethoxylated bisphenol A diacrylate, ethylene glycol dimethacrylate, tricyclodecane dimethanol dimethacrylate, tripropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and diethylene glycol dimethacrylate.

[0021] Preferably, the multifunctional acrylic monomer is a trifunctional or higher acrylic monomer.

[0022] Since trifunctional and above acrylic monomers contain three or more acrylate groups, more cross-linking points can be formed during the curing process, thereby significantly improving the cross-linking density of the coating. High cross-linking density helps to improve the high temperature resistance of the coating, making it stable in high temperature environments and not easily softened or degraded. Coatings with high cross-linking density usually have better electrical insulation properties, which helps prevent short circuits and leakage inside the battery.

[0023] Preferably, the multifunctional acrylic monomer is one or a combination of trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexaacrylate.

[0024] Preferably, the fumed silica is hydrophobic fumed silica, which mainly plays the role of reinforcement, temperature resistance and chemical resistance of the coating.

[0025] Preferably, the particle size of the fumed silica is in the range of 7 to 40 nm, such as 10 nm, 20 nm, 30 nm, etc.

[0026] Preferably, the photoinitiator is one or a combination of 2-hydroxy-methylphenylpropane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-isopropylthioxanthone, and 4-dimethylamino-ethyl benzoate.

[0027] Preferably, the pigment is a blue pigment.

[0028] Preferably, the pigment is one or a combination of phthalocyanine blue, royal blue, dark blue, and Prussian blue.

[0029] Preferably, the pigment is dispersed in a monofunctional acrylic monomer, a difunctional acrylic monomer and a multifunctional acrylic monomer to form a blue color paste without containing an organic solvent.

[0030] Preferably, the blue color paste is prepared by the following method: S1: Put pigment, monofunctional acrylic monomer, difunctional acrylic monomer, multifunctional acrylic monomer, dispersant, defoamer and leveling agent into a mixer and mix and stir; S2: Put the raw materials mixed and stirred evenly in the first step into a sand mill for dispersion and grinding, and control the fineness of the pigment to be below 1μm to obtain a blue color paste.

[0031] Preferably, the dispersant is one or a combination of BYK-190, BYK-160, BYK-2012, BYK-2150, BYK-110.

[0032] Preferably, the defoaming agent is one or a combination of BYK-141, BYK-065, BYK-1790, BYK-1780, BYK-092.

[0033] Preferably, the leveling agent is one or a combination of BYK-333, BYK-3550, BYK-3560, and BYK-354.

[0034] Preferably, the modified polyacrylonitrile copolymer comprises the following raw materials: 0.5-1.5 g polyacrylonitrile, 0.03-0.07 g modified flame retardant, and 20-30 ml tetrahydrofuran.

[0035] Since polyacrylonitrile molecular chains contain a large number of cyano functional groups, these cyano functional groups have high chemical bond energy, making polyacrylonitrile less likely to decompose or change structure at high temperatures, thereby improving the high temperature resistance of the coating. In addition, the molecular structure of polyacrylonitrile does not contain freely movable charges, so polyacrylonitrile is also a good electrical insulating material. By adding modified flame retardants, the overall flame retardant properties of the coating can also be improved.

[0036] Preferably, the modified polyacrylonitrile copolymer is prepared by the following preparation method: weigh 0.5-1.5g polyacrylonitrile and dissolve it in 20-30ml tetrahydrofuran, stir it on a magnetic stirrer at a speed of 650-750r / min for 3-7h, add 0.03-0.07g modified flame retardant, and continue stirring for 10-14h.

[0037] Preferably, the modified flame retardant comprises the following raw materials: 0.6-1.6 g of carboxymethyl chitosan, 95-105 ml of deionized water, 0.04-0.08 g of hexagonal boron nitride, and 95-105 ml of anhydrous ethanol.

[0038] Since the hydroxyl and amino groups contained in carboxymethyl chitosan can release non-flammable gases such as ammonia and carbon dioxide when burned, it will reduce the concentration of oxygen and slow down the spread of heat, thus having a certain flame retardant effect. Hexagonal boron nitride can play a barrier role in the combustion process of polymers due to its ultra-high temperature stability and unique two-dimensional structure, thereby improving the overall flame retardant properties.

[0039] Preferably, the modified flame retardant is prepared by the following preparation method: dissolving 0.6-1.6g of carboxymethyl chitosan in 95-105ml of deionized water, stirring at 70-80°C to obtain a carboxymethyl chitosan solution, adding 0.04-0.08g of hexagonal boron nitride to 95-105ml of anhydrous ethanol, ultrasonically dispersing to obtain a hexagonal boron nitride suspension, pouring the hexagonal boron nitride suspension into the carboxymethyl chitosan solution and stirring, then centrifuging the mixed solution, washing it alternately with deionized water and anhydrous ethanol for 2-4 times, and then freeze-drying it.

[0040] Due to the difference in electronegativity between B and N in hexagonal boron nitride, there is a so-called "lip-lip" interaction between adjacent ester bonds, which makes it difficult to peel off a large amount of hexagonal boron nitride and easy to re-agglomerate. Therefore, carboxymethyl chitosan is used to microencapsulate and modify hexagonal boron nitride. The good film-forming property and easy coke-forming ability of carboxymethyl chitosan are utilized to encapsulate hexagonal boron nitride through hydrogen bond ester bond connection, thereby improving the dispersibility of hexagonal boron nitride.

[0041] In the second aspect, the present application provides a method for preparing a high temperature resistant UV insulating coating for use in new energy batteries, using the following technical solution: A method for preparing a high temperature resistant UV insulating coating for use in new energy batteries comprises the following steps: S1: 10-30 parts of polyurethane modified acrylic resin, 15-40 parts of polysilazane modified acrylic resin, 20-30 parts of epoxy acrylic resin, 10-30 parts of monofunctional acrylic monomer, 10-20 parts of difunctional acrylic monomer, 5-10 parts of multifunctional acrylic monomer, 5-10 parts of modified polyacrylonitrile copolymer, 1-5 parts of fumed silica, 1-5 parts of photoinitiator, 1-5 parts of pigment, 1-5 parts of dispersant, 1-5 parts of defoamer and 1-5 parts of leveling agent are sequentially added into a stirring kettle and stirred evenly to obtain a UV insulating coating.

[0042] In summary, this application has the following beneficial effects: 1. By adopting the above technical scheme, since the high temperature resistant insulating coating adopted is mainly composed of polyurethane modified acrylic resin and polysilazane modified acrylic resin, the carbamate polar group and polyol polyether soft segment group in the polyurethane have excellent adhesion and flexibility on the metal substrate, but the high temperature resistance is general. The silicon nitrogen atoms in the polysilazane modified acrylate are connected by covalent chemical bonds as the main chain, and acrylic acid modification is performed at its end to make it have photocurable properties. The polysilazane modified acrylic resin gives polysilazane photocurable properties and is compatible with other acrylic photocurable monomers and resins.

[0043] Polysilazane contains three elements: silicon, nitrogen and carbon. The silicon-nitrogen bond is a strong polar group with excellent adhesion to metal substrates. After 1400°C, the silicon, nitrogen and carbon in the polysilazane resin will be converted into silicon carbide oxide and silicon carbide nitride. Silicon carbide oxide and silicon carbide nitride have excellent high temperature resistance, which can reach above 1800°C. At the same time, they have excellent adhesion and excellent insulation to metal substrates. By adjusting the functionality and viscosity of different polysilazane-modified acrylic resins, in combination with polyurethane-modified acrylic resins, epoxy acrylic resins and acrylic monomers, UV insulating coatings with excellent high temperature resistance can be achieved.

[0044] 2. Since the multifunctional polyurethane modified acrylic resin is a polyurethane modified acrylic resin with multiple functionalities, the molecules of the multifunctional polyurethane modified acrylic resin contain acrylic functional groups and urethane bonds, so compared with monofunctional resins, the multifunctional polyurethane modified acrylic resin solves the problems of slow curing speed and low hardness of the coating.

[0045] 3. Multifunctional polysilazane-modified acrylic resin is a material that improves performance by combining polysilazane with acrylic resin. Since acrylic resin is polymerized from acrylic acid, methacrylic acid and their derivatives, these monomers form a stable molecular chain structure during the polymerization process. This structure enables acrylic resin to withstand a certain high temperature environment and is not prone to thermal decomposition or combustion. Polysilazane is a polymer with silicon-nitrogen as a repeating main chain, which can be converted into silicon carbide oxide and silicon carbide nitride under high temperature conditions. Therefore, the introduction of polysilazane can further improve the overall high temperature resistance. DETAILED DESCRIPTION

[0046] The present application is further described in detail below in conjunction with Examples 1 to 8 and Comparative Examples 1 to 3.

[0047] raw material Difunctional polyurethane modified acrylic resin Sartomer CN996NS; trifunctional polyurethane modified acrylic resin Sartomer CN989NS; polyvinylsilazane resin Hubei Xinyuhong Biopharmaceutical Technology Co., Ltd.; toluene solvent CAS: 108-88-3; isocyanoethyl methacrylate CAS: 30674-80-7; nitrogen CAS: 7727-37-9; monofunctional epoxy acrylic resin Sartomer CN153NS; difunctional epoxy acrylic resin Sartomer CN2003NS; monofunctional acrylic monomer tetrahydrofuran propylene Acid ester CAS: 2399-48-6; Difunctional acrylic monomer 1,6-hexanediol diacrylate CAS: 13048-33-4; Trifunctional acrylic monomer trimethylolpropane triacrylate CAS: 15625-89-5; Tetrafunctional acrylic monomer pentaerythritol tetraacrylate CAS: 4986-89-4; Fumed silica CAS: 112945-52-5; Photoinitiator 1-hydroxycyclohexylphenyl ketone CAS: 947-19-3; Pigment CAS: 147-14-8; Dispersant BYK-190 Forsman Technology (Beijing) Co., Ltd.; defoamer BYK-141 Hunan Youxin Materials Technology Co., Ltd.; leveling agent BYK-333 Shanghai Jiader Chemical Technology Co., Ltd.; carboxymethyl chitosan CAS: 83512-85-0; deionized water CAS: 7732-18-5; hexagonal boron nitride Zhejiang Yamei Nanotechnology Co., Ltd.; anhydrous ethanol CAS: 64-17-5; polyacrylonitrile CAS: 25014-41-9; tetrahydrofuran CAS: 109-99-9.

[0048] Example 1 A high-temperature-resistant UV insulating coating for use in new energy batteries comprises the following raw materials in parts by weight: 12 parts of difunctional polyurethane-modified acrylic resin, 20 parts of difunctional polysilazane-modified acrylic resin, 30 parts of difunctional epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 10 parts of difunctional acrylic monomer, 5 parts of trifunctional acrylic monomer, 5 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoamer and 1 part of leveling agent.

[0049] Specifically, a preparation method of a high-temperature resistant UV insulating coating for use in new energy batteries comprises the following steps: 12 parts of difunctional polyurethane modified acrylic resin, 20 parts of difunctional polysilazane modified acrylic resin, 30 parts of epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 10 parts of difunctional acrylic monomer, 5 parts of trifunctional acrylic monomer, 5 parts of modified polyacrylonitrile copolymer, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent and 1 part of leveling agent are sequentially added into a stirring kettle and stirred evenly, and then 5 parts of fumed silica are added for high-speed dispersion to obtain a high-temperature resistant UV insulating coating.

[0050] Wherein, the viscosity of the bifunctional polysilazane-modified acrylic resin is 10000 mPa·s.

[0051] The content of the linear polysilazane in the difunctional polysilazane-modified acrylic resin is 35%, and the content of the cyclic polysilazane is 65%.

[0052] The particle size of the fumed silica is 20 nm.

[0053] The preparation method of the modified polyacrylonitrile copolymer comprises the following steps: S1: 1.1 g of carboxymethyl chitosan was dissolved in 100 ml of deionized water, and stirred at 75° C. to obtain a carboxymethyl chitosan solution. 0.06 g of hexagonal boron nitride was added to 100 ml of anhydrous ethanol, and ultrasonic dispersion was performed to obtain a hexagonal boron nitride suspension. The hexagonal boron nitride suspension was poured into the carboxymethyl chitosan solution and stirred. The mixture was then centrifuged, and washed alternately with deionized water and anhydrous ethanol for 3 times, and then freeze-dried to obtain a modified flame retardant. S2: Weigh 1 g of polyacrylonitrile and dissolve it in 25 ml of tetrahydrofuran. After stirring for 5 hours on a magnetic stirrer at a speed of 700 r / min, add 0.05 g of modified flame retardant and continue stirring for 12 hours to obtain modified polyacrylonitrile.

[0054] The preparation method of the difunctional polysilazane-modified acrylic resin comprises the following steps: S1: 8.0 g of polyvinylsilazane resin was added dropwise into a 50 mL round-bottom flask, the average degree of polymerization of polyvinylsilazane was 20, diluted with 32 g of toluene solvent, stirred at medium speed for 15 min to mix evenly, then isocyanoethyl methacrylate was slowly added dropwise, and the molar ratio of the difunctional polysilazane-modified acrylate was 10:1. After mixing evenly, the flask was connected to a Schlenk glass tube with a piston and sealed; S2: Fill the glove bag with 99.999% high-purity nitrogen, evacuate and replace after it is full, repeat this step 3 times, place the flask containing the reaction solution in an oil bath at 50°C in an air atmosphere, stir magnetically at medium speed, keep the reaction at a constant temperature and away from light for 20 hours, then cool and stop the reaction; S3: After cooling, the flask was moved to a 30° C. water bath, slowly magnetically stirred, connected to a suction filtration device, vacuumed, and then the piston of the glass tube was opened and vacuumed continuously to remove the toluene solvent and other low molecular weight compound impurities to obtain a difunctional polysilazane-modified acrylic resin.

[0055] Example 2 The difference from Example 1 is that the UV insulating coating contains the following raw materials in parts by weight: 20 parts of difunctional polyurethane modified acrylic resin, 25 parts of difunctional polysilazane modified acrylic resin, 20 parts of difunctional epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 10 parts of difunctional acrylic monomer, 3 parts of trifunctional acrylic monomer, 1 part of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent, and 1 part of leveling agent.

[0056] Example 3 The difference from Example 1 is that the UV insulating coating contains the following raw materials in parts by weight: 10 parts of difunctional polyurethane modified acrylic resin, 30 parts of difunctional polysilazane modified acrylic resin, 10 parts of difunctional epoxy acrylic resin, 20 parts of monofunctional acrylic monomer, 14 parts of difunctional acrylic monomer, 3 parts of trifunctional acrylic monomer, 3 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent, and 1 part of leveling agent.

[0057] Example 4 The difference from Example 1 is that the UV insulating coating comprises the following raw materials in parts by weight: 20 parts of difunctional polyurethane modified acrylic resin, 10 parts of trifunctional polysilazane modified acrylic resin, 20 parts of difunctional epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 14 parts of difunctional acrylic monomer, 3 parts of trifunctional acrylic monomer, 2 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoamer, and 1 part of leveling agent; The difference between the preparation method of the trifunctional polysilazane-modified acrylic resin and that of Example 1 is that the molar ratio of the trifunctional polysilazane-modified acrylic resin is 20:3.

[0058] Example 5 The difference from Example 1 is that the UV insulating coating contains the following raw materials in parts by weight: 20 parts of trifunctional polyurethane modified acrylic resin, 5 parts of difunctional polysilazane modified acrylic resin, 10 parts of difunctional epoxy acrylic resin, 20 parts of monofunctional acrylic monomer, 24 parts of difunctional acrylic monomer, 3 parts of trifunctional acrylic monomer, 4 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent, and 1 part of leveling agent.

[0059] Example 6 The difference from Example 1 is that the UV insulating coating contains the following raw materials in parts by weight: 15 parts of trifunctional polyurethane modified acrylic resin, 25 parts of trifunctional polysilazane modified acrylic resin, 20 parts of difunctional epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 14 parts of difunctional acrylic monomer, 3 parts of trifunctional acrylic monomer, 5 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent, and 1 part of leveling agent.

[0060] Example 7 The difference from Example 1 is that the UV insulating coating contains the following raw materials in parts by weight: 10 parts of trifunctional polyurethane modified acrylic resin, 35 parts of trifunctional polysilazane modified acrylic resin, 15 parts of difunctional epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 7 parts of difunctional acrylic monomer, 10 parts of trifunctional acrylic monomer, 5 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent, and 1 part of leveling agent.

[0061] Example 8 The difference from Example 1 is that the UV insulating coating contains the following raw materials in parts by weight: 10 parts of difunctional polyurethane modified acrylic resin, 40 parts of trifunctional polysilazane modified acrylic resin, 10 parts of monofunctional epoxy acrylic resin, 10 parts of monofunctional acrylic monomer, 14 parts of difunctional acrylic monomer, 3 parts of tetrafunctional acrylic monomer, 5 parts of modified polyacrylonitrile copolymer, 5 parts of fumed silica, 4 parts of photoinitiator, 1 part of pigment, 1 part of dispersant, 1 part of defoaming agent, and 1 part of leveling agent.

[0062] Comparative Example 1 The difference from Example 1 is that the polyurethane-modified acrylic resin is replaced by an equal amount of polysilazane-modified acrylic resin.

[0063] Comparative Example 2 The difference from Example 1 is that carboxymethyl chitosan is replaced by an equal amount of isopropanol.

[0064] Comparative Example 3 The difference from Example 1 is that no modified polyacrylonitrile is added.

[0065] Performance testing 1. High temperature resistance test Three samples were taken from Examples 1 to 8 and Comparative Examples 1 to 3, and sprayed evenly on the metal surface. Before spraying, the metal surface was treated with laser or plasma to remove oil and impurities. The spraying thickness was 100-120 μm, and then UV curing was performed. During spraying, a two-spraying method was adopted, first spraying half of the required full-solid UV insulating coating to reach the paint layer thickness, and then spraying the other half of the required full-solid UV insulating coating after curing was completed.

[0066] (1) Insulation performance after high temperature: spray the high temperature resistant UV insulation coating on the model 3003 aluminum plate, place it in a 500℃ high temperature oven for 30 minutes after UV curing, take it out and place it at room temperature, and use a withstand voltage tester to test the insulation performance; (2) Surface state after high temperature: spray the high temperature resistant UV insulating coating on the 3003 aluminum plate. After UV curing, place it in a 500℃ high temperature oven for 30 minutes. After taking it out and placing it at room temperature, observe whether it turns yellow. (3) Adhesion after high temperature: spray the high temperature resistant UV insulating coating on the model 3003 aluminum plate, place it in a 500℃ high temperature oven for 30 minutes after UV curing, take it out and place it at room temperature, and then test the coating adhesion according to ISO-2409 standard; (4) Impact resistance after high temperature: The high temperature resistant UV insulating coating was sprayed on a 3003 aluminum plate. After UV curing, it was placed in a 500°C high temperature oven for 30 minutes. After being taken out and placed at room temperature, the impact resistance of the coating was tested according to GB / T 1732-2020 standard.

[0067] The test data are shown in Table 1.

[0068] Table 1 High temperature resistance test table of Example 1 to Example 8 and Comparative Example 1 to Comparative Example 3

[0069] 2. Flame retardant properties Three samples were taken from each of Examples 1 to 8 and Comparative Examples 1 to 3, and the high temperature resistance performance was tested according to GB / T 2406.1-2008 "Determination of Combustion Behavior of Plastics by Oxygen Index Method" and UL-94.

[0070] The test data are shown in Table 2.

[0071] Table 2 Flame retardant performance test table of Example 1 to Example 8 and Comparative Example 1 to Comparative Example 3

[0072] Combining Example 1 and Comparative Example 1 and Table 1 and Table 2, it can be seen that after high-temperature baking, the insulation of Comparative Example 1 fails, the surface appears black and peeling, and the adhesion reaches Level 5. At the same time, the limiting oxygen index of Comparative Example 1 decreases slightly. This shows that replacing the polyurethane modified acrylic resin with the same amount of polysilazane modified acrylic resin will significantly reduce the high temperature resistance and insulation performance of the UV coating, and also affect the flame retardant properties of the UV coating to a certain extent.

[0073] Combining Example 1 and Comparative Example 2 and Table 1 and Table 2, it can be seen that Comparative Example 2 can maintain good insulation after high-temperature baking, and there is no sign of yellowing on the surface, and the adhesion is also at level 0, but the limiting oxygen index of Comparative Example 2 is significantly reduced, which shows that compared with adding isopropanol, adding carboxymethyl chitosan can effectively improve the flame retardant properties of UV coatings.

[0074] The reason is that the hydroxyl and amino groups contained in carboxymethyl chitosan can release non-combustible gases such as ammonia and carbon dioxide when burned, which will reduce the concentration of oxygen and slow down the spread of heat, thus having a certain flame retardant effect. In addition, the difference in electronegativity between B and N in hexagonal boron nitride leads to the so-called "lip-lip" interaction between adjacent ester bonds, making it difficult to peel off a large amount of hexagonal boron nitride and easy to re-agglomerate. Therefore, carboxymethyl chitosan is used to microencapsulate and modify hexagonal boron nitride. The good film-forming property and easy coke-forming ability of carboxymethyl chitosan are utilized to encapsulate hexagonal boron nitride through hydrogen bond ester bond connection, thereby improving the dispersibility of hexagonal boron nitride.

[0075] Combining Example 1 and Comparative Example 3 with Tables 1 and 2, it can be seen that Comparative Example 3 can maintain good insulation after high-temperature baking, and there is no sign of yellowing on the surface, and the adhesion is also at level 0, but the limiting oxygen index of Comparative Example 3 is significantly reduced, and the UL-94 level is V1, which shows that compared with not adding modified polyacrylonitrile, adding modified polyacrylonitrile can effectively improve the flame retardant properties of UV coatings.

[0076] The reason is that polyacrylonitrile molecular chains contain a large amount of cyano functionalities, which have high chemical bond energy, making it difficult for polyacrylonitrile to decompose or change its structure at high temperatures, thereby improving the high temperature resistance of the coating. In addition, the molecular structure of polyacrylonitrile does not contain charges that can move freely, so polyacrylonitrile is also a good electrical insulating material. By adding modified flame retardants, hexagonal boron nitride can play a barrier role in the combustion process of the polymer due to its ultra-high temperature stability and unique two-dimensional structure, thereby improving the overall flame retardant properties of the coating.

[0077] It can be seen from Example 3 and Example 1-Example 2, Example 6-Example 8 and Table 1 and Table 2 that Example 1-Example 2 and Example 6-Example 8 can still maintain good insulation after high-temperature baking, and there is no sign of yellowing on the surface. The adhesion is also at level 0, the limiting oxygen index has a slight decrease, and the UL-94 flame retardant grade is VO. However, compared with Example 3, the comprehensive performance of Example 3 is better. This shows that the addition amount of each raw material in Example 3 is optimal, which is beneficial to significantly improve the high temperature resistance, insulation and flame retardant properties of the UV coating, and is suitable for new energy batteries or energy storage systems as insulating protective films.

[0078] Combining Example 3 and Example 4-Example 5 and Table 1 and Table 2, it can be seen that Example 4 and Example 5 have insulation failure after high-temperature baking, and the surface appears serious yellowing. The adhesion of Example 4 reaches level 3, and the adhesion of Example 5 reaches level 4. The limiting oxygen index of Example 4 and Example 5 also decreases significantly, which shows that during the high-temperature baking process, a small amount of polysilazane-modified acrylic resin cannot effectively synergistically improve the high temperature resistance, so adding a small amount of polysilazane-modified acrylic resin will reduce the high temperature resistance, insulation performance and flame retardant properties of the UV coating.

[0079] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high temperature resistant UV insulating coating for new energy batteries, characterized in that: The invention comprises the following raw materials in parts by weight: 10-30 parts of polyurethane modified acrylic resin, 15-40 parts of polysilazane modified acrylic resin, 20-30 parts of epoxy acrylic resin, 10-30 parts of monofunctional acrylic monomer, 10-20 parts of difunctional acrylic monomer, 5-10 parts of multifunctional acrylic monomer, 5-10 parts of modified polyacrylonitrile copolymer, 1-5 parts of fumed silica, 1-5 parts of photoinitiator, 1-5 parts of pigment, 1-5 parts of dispersant, 1-5 parts of defoaming agent and 1-5 parts of leveling agent.

2. The high temperature resistant UV insulating coating for new energy batteries according to claim 1, characterized in that: The polyurethane modified acrylic resin is one or a combination of difunctional polyurethane modified acrylic resin, trifunctional polyurethane modified acrylic resin, tetrafunctional polyurethane modified acrylic resin, pentafunctional polyurethane modified acrylic resin and hexafunctional polyurethane modified acrylic resin.

3. The high temperature resistant UV insulating coating for new energy batteries according to claim 1, characterized in that: The functionality of the polysilazane-modified acrylic resin is one or a combination of difunctional polysilazane-modified acrylic resin, trifunctional polysilazane-modified acrylic resin, and tetrafunctional polysilazane-modified acrylic resin.

4. The high temperature resistant UV insulating coating for new energy batteries according to claim 3 is characterized in that: The viscosity of the polysilazane-modified acrylic resin is 5000-80000 mPa·s.

5. The high temperature resistant UV insulating coating for new energy batteries according to claim 1, characterized in that: The modified polyacrylonitrile copolymer comprises the following raw materials: 0.5-1.5 g of polyacrylonitrile, 0.03-0.07 g of a modified flame retardant, and 20-30 ml of tetrahydrofuran.

6. The high temperature resistant UV insulating coating for new energy batteries according to claim 5, characterized in that: The modified polyacrylonitrile copolymer is prepared by the following preparation method: 0.5-1.5 g of polyacrylonitrile is weighed and dissolved in 20-30 ml of tetrahydrofuran, and stirred on a magnetic stirrer at a speed of 650-750 r / min for 3-7 hours, and then 0.03-0.07 g of modified flame retardant is added, and stirring is continued for 10-14 hours.

7. The high temperature resistant UV insulating coating for new energy batteries according to claim 6, characterized in that: The modified flame retardant comprises the following raw materials: 0.6-1.6 g of carboxymethyl chitosan, 95-105 ml of deionized water, 0.04-0.08 g of hexagonal boron nitride, and 95-105 ml of anhydrous ethanol.

8. The high temperature resistant UV insulating coating for new energy batteries according to claim 7, characterized in that: The modified flame retardant is prepared by the following preparation method: 0.6-1.6g of carboxymethyl chitosan is dissolved in 95-105ml of deionized water, and the mixture is stirred at 70-80°C to obtain a carboxymethyl chitosan solution; 0.04-0.08g of hexagonal boron nitride is added into 95-105ml of anhydrous ethanol, and the mixture is ultrasonically dispersed to obtain a hexagonal boron nitride suspension; the hexagonal boron nitride suspension is poured into the carboxymethyl chitosan solution and stirred; the mixture is then centrifuged, and the mixture is alternately washed with deionized water and anhydrous ethanol for 2-4 times, and then freeze-dried.

9. A preparation method for preparing a high temperature resistant UV insulating coating for use in new energy batteries as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1: 10-30 parts of polyurethane modified acrylic resin, 15-40 parts of polysilazane modified acrylic resin, 20-30 parts of epoxy acrylic resin, 10-30 parts of monofunctional acrylic monomer, 10-20 parts of difunctional acrylic monomer, 5-10 parts of multifunctional acrylic monomer, 5-10 parts of modified polyacrylonitrile copolymer, 1-5 parts of fumed silica, 1-5 parts of photoinitiator, 1-5 parts of pigment, 1-5 parts of dispersant, 1-5 parts of defoamer and 1-5 parts of leveling agent are sequentially added into a stirring kettle and stirred evenly to obtain a UV insulating coating.

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