Photocuring ink, insulating coating, battery shell, preparation method of battery shell and battery

Abstract

The invention provides light-cured printing ink, an insulating coating, a battery shell, a preparation method of the battery shell and a battery, the light-cured printing ink comprises acrylic resin, an active monomer and an initiator, and the initiator can promote the active monomer and the acrylic resin to generate a polymerization reaction, so that the light-cured printing ink is cured. The initiator comprises a deep-layer curing initiator, a shallow-layer curing initiator and an amine co-initiator, and the absorption wavelength of the deep-layer curing initiator is 300-400 nm. The deep curing initiator ensures that the deep curing initiator can be effectively activated to generate free radicals in a deep area, so that deep curing is realized. The superficial layer curing initiator forms an excited state under illumination, the superficial layer curing initiator in the excited state captures hydrogen atoms from the amine co-initiator to generate active free radicals and amine free radicals, the amine free radicals can react with oxygen to generate peroxyamine, the oxygen inhibition problem is solved, surface layer curing and bottom layer curing can be achieved at the same time when the light-cured ink is cured, and the light-cured ink has the advantages of simple preparation process and low cost. Further, the mechanical property of the insulating coating is improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a photocurable ink, an insulating coating, a battery casing, a preparation method thereof, and a battery. Background Art

[0002] Currently, lithium-ion batteries generally have aluminum shells. In order to improve the insulation performance of the lithium-ion battery surface, a spray printing process is generally used to print a layer of insulating ink on the surface of the aluminum shell, and then the insulating ink is photocured to obtain an integrated insulating coating.

[0003] However, during the curing process of insulating ink, due to the problem of oxygen inhibition, the surface ink is prone to incomplete curing, resulting in the bottom layer of the insulating coating being cured while the surface layer is not cured, reducing the mechanical properties of the insulating coating, which needs further improvement. Summary of the Invention

[0004] The embodiments of the present application provide a photocurable ink, an insulating coating, a battery housing, a preparation method thereof, and a battery, aiming to solve the aforementioned technical problems.

[0005] In a first aspect, an embodiment of the present application provides a photocurable ink, comprising: an acrylic resin, a reactive monomer, and an initiator;

[0006] The initiator comprises a deep curing initiator, a shallow curing initiator and an amine auxiliary initiator. The absorption wavelength of the deep curing initiator is 300nm-400nm, and the shallow curing initiator comprises a thioxanthone compound.

[0007] In one embodiment, the absorption wavelength of the initiator is 365 nm or 395 nm; and / or

[0008] The mass percentage of the deep curing initiator in the photocurable ink is 2%-5%; and / or

[0009] The sum of the mass of the shallow curing initiator and the amine co-initiator in the light-curable ink is 1% to 3% by mass; and / or

[0010] The mass ratio between the shallow curing initiator and the amine co-initiator is 1:(0.2-0.5); and / or

[0011] The mass percentage of the initiator in the photocurable ink is 3%-8%; and / or

[0012] The mass percentage of the active monomer in the photocurable ink is 25%-50%; and / or

[0013] The mass percentage of the acrylic resin in the light-curable ink is 40%-60%.

[0014] In one embodiment, the deep curing initiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanocene, bis-2,6-difluoro-3-pyrrolphenyltitanocene, 2-hydroxy-2-methyl-1-phenylpropanone, and 1-hydroxycyclohexylphenyl ketone; and / or

[0015] The thioxanthone compound includes at least one of 2-chlorothioxanthone, isopropylthioxanthone and 2,4-diethylthioxanthone; and / or

[0016] The amine co-initiator comprises at least one of an active amine and a tertiary amine benzoate; and / or

[0017] The acrylic resin includes polycarbonate polyurethane acrylate and linear aliphatic epoxy acrylate; and / or

[0018] The reactive monomers include monofunctional acrylate monomers, difunctional acrylate monomers and multifunctional acrylate monomers, and the functionality of the multifunctional acrylate monomers is greater than or equal to 3.

[0019] In one embodiment, the active amine includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylamine, triethylamine, isophoronediamine, and 1,2-cyclohexanediamine; and / or

[0020] The tertiary amine benzoate includes at least one of ethyl 4-(N,N-dimethylamino)benzoate, ethyl N,N-diphenylmethylcarboxylate, and 2-ethylhexyl N,N-dimethylbenzoate; and / or

[0021] The monofunctional acrylate monomer includes at least one of isobornyl acrylate, isodecyl acrylate, lauryl acrylate or hexadecyl acrylate; and / or

[0022] The bifunctional acrylate monomer includes at least one of 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and ethoxylated bisphenol A diacrylate; and / or

[0023] The multifunctional acrylate monomer includes at least one of trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol penta / hexaacrylate, and tris(2-hydroxyethyl)isocyanurate triacrylate.

[0024] In one embodiment, the mass ratio of the monofunctional acrylate monomer, the difunctional acrylate monomer and the multifunctional acrylate monomer is (3-5):1:(0.3-0.5); and / or

[0025] The molecular weight of the polycarbonate polyurethane acrylate is 500-1200; and / or

[0026] The molecular weight of the linear aliphatic epoxy acrylate is 500-1200; and / or

[0027] The mass ratio between the polycarbonate polyurethane acrylate and the linear aliphatic epoxy acrylate is (0.5-3):1; and / or

[0028] The polycarbonate polyurethane acrylate has a general structural formula shown in structural formula (1):

[0029]

[0030] Wherein, in structural formula (1), R1 is selected from a benzene ring or a C1-C6 substituted or unsubstituted alkyl group, and / or, R2 is selected from a substituted or unsubstituted cyclohexane group, and / or, R3 and R4 are each independently selected from a C1-C6 substituted or unsubstituted alkyl group, and / or, n is selected from an integer of 1-10, and / or, m is selected from an integer of 1-10; and / or

[0031] The linear aliphatic epoxy acrylate has the general structural formula shown in structural formula (2):

[0032]

[0033] Wherein, in structural formula (2), R1 is selected from C1-C10 substituted or unsubstituted linear or branched alkyl groups, and / or x is selected from integers of 1-6.

[0034] In one embodiment, the photocurable ink further includes a pigment, a wetting agent, an inhibitor and / or a diluent.

[0035] In one embodiment, the wetting agent includes at least one of polyether-modified silicone and polyester-modified silicone; and / or

[0036] The polymerization inhibitor comprises at least one of hydroquinone and p-methoxyphenol; and / or

[0037] The diluent includes at least one of isobornyl acrylate, isodecyl acrylate, lauryl acrylate or hexadecyl acrylate. The test results are shown in Table 3.

[0038] In one embodiment, the mass percentage of the pigment in the ink is 0.5-1%; and / or

[0039] The mass percentage of the wetting agent in the ink is 0.5-2.5%; and / or

[0040] The mass percentage of the polymerization inhibitor in the ink is 0.1-0.5%; and / or

[0041] The mass percentage of the diluent in the ink is 4-5%; and / or

[0042] The particle size D50 of the pigment is ≤0.4 μm.

[0043] In a second aspect, an embodiment of the present application further provides an insulating coating, wherein the insulating coating is formed by the photocurable ink as described above.

[0044] In a third aspect, an embodiment of the present application further provides a battery housing, comprising:

[0045] Main body;

[0046] An insulating coating layer is provided on at least a portion of the outer surface of the main body, and the insulating coating layer is formed of the light-curable ink as described above.

[0047] In a fourth aspect, an embodiment of the present application further provides a method for preparing a battery casing, the method comprising:

[0048] providing a main body portion of a battery housing;

[0049] Using the aforementioned light-curable ink as a raw material, spraying an ink layer on at least a portion of the outer surface of the main body;

[0050] The ink layer is cured by ultraviolet light irradiation to form an insulating coating, thereby obtaining the battery shell.

[0051] In one embodiment, the thickness of the ink layer is 50 μm-150 μm; and / or

[0052] The light source of the ultraviolet light includes an LED lamp, and / or the wavelength of the ultraviolet light is 365nm or 395nm, and / or the curing time is 1s-10s.

[0053] In a fifth aspect, an embodiment of the present application further provides a battery, comprising the insulating coating as described above, or comprising the battery casing as described above, or a battery casing prepared using the method as described above.

[0054] Beneficial effects of the embodiments of the present application:

[0055] The photocurable ink of the embodiment of the present application includes an acrylic resin, an active monomer and an initiator. The initiator can promote the polymerization reaction between the active monomer and the acrylic resin to achieve the curing of the photocurable ink. The initiator includes a deep curing initiator, a shallow curing initiator and an amine co-initiator. The absorption wavelength of the deep curing initiator is 300nm-400nm. Generally, the longer the wavelength of light, the better the ability of light to penetrate the material. Therefore, the ink in the deep area usually requires longer wavelength light during photocuring, and the absorption wavelength of the deep curing initiator is 300nm-400nm. The deep curing initiator can absorb light with a matching longer wavelength, ensuring that the deep curing initiator can also be effectively activated to generate free radicals in the deep area, thereby achieving deep curing. Shallow layer curing initiators include thioxanthone compounds. Due to their high absorption efficiency and rapid initiation ability, thioxanthone compounds can meet the needs of surface curing. Thioxanthone compounds form an excited state under light. The electron-rich sulfur atoms in the molecular structure of thioxanthone compounds enhance the molecule's ability to absorb light, enabling the excited state to be efficiently generated. The excited state thioxanthone compounds extract hydrogen atoms from amine co-initiators through intramolecular hydrogen abstraction reactions to generate active free radicals and amine free radicals. The amine free radicals can react with oxygen to generate peroxyamines, thereby consuming oxygen in the surface area, thereby reducing the interference of oxygen on surface curing, allowing the surface area to complete surface curing before oxygen diffuses to the reaction interface, improving the oxygen inhibition problem, and improving the surface curing effect of the coating. When the photocurable ink is cured, surface curing and bottom curing can be achieved simultaneously, so that the shrinkage stress is evenly distributed during curing, reducing local stress concentration, while ensuring uniform cross-linking of the insulating coating as a whole, improving the overall strength of the coating, and thus improving the mechanical properties of the insulating coating. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state; while "inside" and "outside" refer to the outline of the device.

[0057] In the related art, during the curing process of insulating ink, due to the problem of oxygen inhibition, the surface ink is prone to incomplete curing, resulting in the bottom layer of the insulating coating being cured while the surface layer is not cured, which needs further improvement.

[0058] The present application provides a photocurable ink, which includes an acrylic resin, an active monomer and an initiator. The initiator can promote the polymerization reaction between the active monomer and the acrylic resin to enable the photocurable ink to be cured. The initiator includes a deep curing initiator, a shallow curing initiator and an amine co-initiator. The absorption wavelength of the deep curing initiator is 300nm-400nm. Generally, the longer the wavelength of light, the better the ability of light to penetrate the material. Therefore, the ink in the deep area usually requires longer wavelength light during photocuring, and the absorption wavelength of the deep curing initiator is 300nm-400nm. The deep curing initiator can absorb light with a matching longer wavelength to ensure that the deep curing initiator can also be effectively activated to generate free radicals in the deep area, thereby achieving deep curing. Shallow layer curing initiators include thioxanthone compounds. Due to their high absorption efficiency and rapid initiation ability, thioxanthone compounds can meet the needs of surface curing. Thioxanthone compounds form an excited state under light. The electron-rich sulfur atoms in the molecular structure of thioxanthone compounds enhance the molecule's ability to absorb light, enabling the excited state to be efficiently generated. The excited state thioxanthone compounds extract hydrogen atoms from amine co-initiators through intramolecular hydrogen abstraction reactions to generate active free radicals and amine free radicals. The amine free radicals can react with oxygen to generate peroxyamines, thereby consuming oxygen in the surface area, thereby reducing the interference of oxygen on surface curing, allowing the surface area to complete surface curing before oxygen diffuses to the reaction interface, improving the oxygen inhibition problem, and improving the surface curing effect of the coating. When the photocurable ink is cured, surface curing and bottom curing can be achieved simultaneously, so that the shrinkage stress is evenly distributed during curing, reducing local stress concentration, while ensuring uniform cross-linking of the insulating coating as a whole, improving the overall strength of the coating, and thus improving the mechanical properties of the insulating coating.

[0059] In one embodiment, the absorption wavelength of the initiator is 365nm or 395nm. It should be noted that the initiator is a composition including a deep curing initiator, a shallow curing initiator and an amine co-initiator. The absorption wavelength of the initiator refers to the threshold value required for the absorption intensity of light by the composition to initiate curing. When the absorption wavelength of the initiator is 365nm or 395nm, the initiator containing multiple components can have significant absorption at a wavelength of 365nm or 395nm and can efficiently initiate polymerization reactions. Since the wavelength range of the light waves emitted by the electrodeless lamp is generally 200nm-450nm, the selection requirements for the initiator are low. Therefore, there are electrodeless lamps on the market as light sources for photocuring. However, electrodeless lamps have the disadvantages of severe heat generation, increased equipment temperature, short service life, and high cost, which limit their large-scale application. LED lamps have the advantages of low heat generation, long equipment service life, and low cost, and can be used on a large scale for photocuring of inks. However, the wavelength range of ultraviolet light emitted by LED lamps is relatively narrow, typically 365nm or 395nm, placing high demands on the type of initiator. However, the initiator in this embodiment has an absorption wavelength of 365nm or 395nm, which closely matches the wavelength of the ultraviolet light emitted by the LED lamp. The initiator's absorption wavelength is effectively absorbed by the initiator, effectively initiating the photocuring reaction. Therefore, in this embodiment, through the synergistic effect of various components, including the deep-cure initiator, the shallow-cure initiator, and the amine co-initiator, the absorption wavelength of the initiator containing multiple components is reduced to 365nm or 395nm. This allows the photocurable ink to use LED lamps as a light source, reducing equipment life and costs while ensuring a good curing effect.

[0060] In one embodiment, the mass percentage of the deep-layer curing initiator in the photocurable ink is 2%-5%. Alternatively, the mass percentage of the deep-layer curing initiator in the photocurable ink can be any one of 2%, 3%, 4%, 5%, or any range between two of these, without limitation. In this embodiment, if the mass percentage of the deep-layer curing initiator in the photocurable ink is too high or too low, it can easily lead to poor consistency in the curing degree between the surface layer and the deep layer of the insulating coating.

[0061] In one embodiment, the combined mass percentage of the shallow curing initiator and the amine co-initiator in the photocurable ink is 1%-3%. Alternatively, the combined mass percentage of the shallow curing initiator and the amine co-initiator in the photocurable ink can be any one of 1%, 1.5%, 2%, 2.5%, 3%, or any two thereof, without limitation. In this embodiment, if the combined mass percentage of the shallow curing initiator and the amine co-initiator is too high, the ink surface may cure too quickly, resulting in an uneven surface. This may cause defects such as orange peel and craters on the insulating coating surface, affecting the appearance and performance of the insulating coating. If the combined mass percentage of the shallow curing initiator and the amine co-initiator is too low, the ink surface may not fully cure.

[0062] In one embodiment, the mass ratio between the shallow curing initiator and the amine co-initiator is 1:(0.2-0.5). Optionally, the mass ratio between the shallow curing initiator and the amine co-initiator can be any one of 1:0.2, 1:0.3, 1:0.4, 1:0.5, etc. or a range between any two of them, which is not limited here. In this embodiment, the shallow curing initiator mainly generates free radicals with the amine co-initiator through hydrogen abstraction reaction to promote ink curing. When the mass ratio between the shallow curing initiator and the amine co-initiator is too small, it is easy to cause the shallow curing initiator to generate too few free radicals, and the amine co-initiator alone has low initiation efficiency, resulting in a slower curing speed and incomplete surface curing. When the mass ratio between the shallow curing initiator and the amine co-initiator is too much, it is easy to cause the content of the amine co-initiator to be too little, and the effect of the amine co-initiator in improving oxygen inhibition is not ideal.

[0063] In one embodiment, the mass percentage of the initiator in the photocurable ink is 3%-8%. Alternatively, the mass percentage of the initiator in the photocurable ink can be any one of 3%, 4%, 5%, 6%, 8%, or any range between two of these, without limitation. In this embodiment, excessive initiator content can lead to an overly rapid curing reaction, potentially causing internal stress or cracks in the insulating coating. Excessive initiator content can result in incomplete curing, impacting the mechanical strength and durability of the insulating coating.

[0064] In one embodiment, the deep curing initiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanocene, bis-2,6-difluoro-3-pyrrolphenyltitanocene, 2-hydroxy-2-methyl-1-phenylpropanone, and 1-hydroxycyclohexylphenyl ketone.

[0065] In one embodiment, the thioxanthone compound includes at least one of 2-chlorothioxanthone, isopropylthioxanthone, and 2,4-diethylthioxanthone.

[0066] In one embodiment, the amine co-initiator includes at least one of an active amine and a tertiary amine benzoate.

[0067] In one embodiment, the active amine includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylamine, triethylamine, isophoronediamine, and 1,2-cyclohexanediamine.

[0068] In one embodiment, the tertiary amine benzoate includes at least one of ethyl 4-(N,N-dimethylamino)benzoate, ethyl N,N-diphenylmethanecarboxylate, and 2-ethylhexyl N,N-dimethylbenzoate.

[0069] In one embodiment, the mass percentage of the active monomer in the photocurable ink is 25%-50%. Alternatively, the mass percentage of the active monomer in the photocurable ink can be any one of 25%, 30%, 35%, 40%, 50%, or any two thereof, without limitation herein. In this embodiment, if the mass percentage of the active monomer in the photocurable ink is too high, the excess active monomer can easily reduce the crosslinking density of the acrylic resin, resulting in a decrease in the mechanical properties of the insulating coating. Furthermore, the more active monomer, the higher the UV energy required for complete curing. Given limited UV energy, excessive active monomer can easily lead to incomplete curing. The active monomer can reduce the viscosity of the photocurable ink. However, if the mass percentage of the active monomer in the photocurable ink is too low, the viscosity of the photocurable ink can easily increase, limiting the penetration of UV light into the photocurable ink and resulting in poor curing.

[0070] In one embodiment, the reactive monomers include monofunctional acrylate monomers, difunctional acrylate monomers, and multifunctional acrylate monomers, with the multifunctional acrylate monomers having a functionality greater than or equal to 3. In this embodiment, the monofunctional acrylate monomers can increase the flexibility and adhesion of the insulating coating, while the difunctional acrylate monomers and multifunctional acrylate monomers can improve the electrical insulation, electrolyte resistance, and crosslink density of the insulating coating. The combined use of the monofunctional acrylate monomers, difunctional acrylate monomers, and multifunctional acrylate monomers can produce a synergistic effect, improving the flexibility, electrical insulation, solvent resistance, and adhesion of the insulating coating.

[0071] In one embodiment, the monofunctional acrylate monomer includes at least one of isobornyl acrylate, isodecyl acrylate, lauryl acrylate, or hexadecyl acrylate.

[0072] In one embodiment, the bifunctional acrylate monomer includes at least one of 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and ethoxylated bisphenol A diacrylate.

[0073] In one embodiment, the multifunctional acrylate monomer includes at least one of trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol penta / hexaacrylate, and tris(2-hydroxyethyl)isocyanurate triacrylate.

[0074] In one embodiment, the mass ratio of the monofunctional acrylate monomer, the difunctional acrylate monomer, and the multifunctional acrylate monomer is (3-5):1:(0.3-0.5). Optionally, the mass ratio of the monofunctional acrylate monomer, the difunctional acrylate monomer, and the multifunctional acrylate monomer can be any one of 3:1:0.5, 4:1:0.5, 5:1:0.5, 3:1:0.4, 5:1:0.3, etc., or a range between any two of them, which is not limited here. In this embodiment, when the mass of the monofunctional acrylate monomer is too much and the mass of the multifunctional acrylate monomer is too little, it is easy to cause the cross-linking density of the insulating coating to be too low and the high-temperature resistance to be poor. When the mass of the monofunctional acrylate monomer is too little and the mass of the multifunctional acrylate monomer is too much, it is easy to cause the insulating coating to be incompletely cured, the insulating coating to be sticky, the insulating coating to be easily brittle, and the aging resistance to be poor.

[0075] In one embodiment, the mass percentage of the acrylic resin in the photocurable ink is 40%-60%. Alternatively, the mass percentage of the acrylic resin in the photocurable ink can be any one of 40%, 45%, 50%, 55%, 60%, etc., or any range between any two thereof, without limitation herein.

[0076] In one embodiment, the acrylic resin includes polycarbonate polyurethane acrylate and linear aliphatic epoxy acrylate. Polycarbonate polyurethane acrylate has a carbonate group, which has low polarity and is not easily chemically reacted. This gives the polycarbonate polyurethane acrylate good hydrolysis resistance and chemical corrosion resistance, making the insulating coating less susceptible to aging, decomposition, and yellowing during high temperature, high humidity, and long-term use. The linear aliphatic epoxy acrylate maintains the high insulating properties of the epoxy resin itself. At the same time, the linear structure of the linear aliphatic epoxy acrylate gives the insulating coating a good hydrophobic effect, further improving the hydrophobic properties of the insulating coating. The combination of polycarbonate polyurethane acrylate and linear aliphatic epoxy acrylate can improve the overall performance of the insulating coating.

[0077] In one embodiment, the molecular weight of the polycarbonate polyurethane acrylate is 500-1200. Alternatively, the molecular weight of the polycarbonate polyurethane acrylate can be any one of 500, 700, 800, 900, 1000, 1200, or any two thereof, without limitation. In this embodiment, the molecular weight of the polycarbonate polyurethane acrylate is set to 500-1200 to ensure that the UV-curable ink has an appropriate viscosity, thereby reducing ink smearing and clogging during spraying.

[0078] In one embodiment, the molecular weight of the linear aliphatic epoxy acrylate is 500-1200. Alternatively, the molecular weight of the linear aliphatic epoxy acrylate can be any one of 500, 700, 800, 900, 1000, 1200, or any two thereof, without limitation. In this embodiment, the molecular weight of the linear aliphatic epoxy acrylate is set to 500-1200 to ensure that the UV-curable ink has an appropriate viscosity, thereby reducing ink smearing and clogging during spraying.

[0079] In one embodiment, the mass ratio of the polycarbonate polyurethane acrylate to the linear aliphatic epoxy acrylate is (0.5-3):1. Alternatively, the mass ratio of the polycarbonate polyurethane acrylate to the linear aliphatic epoxy acrylate can be any one of 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, or the like, or a range between any two thereof, without limitation. In this embodiment, if the mass ratio of the polycarbonate polyurethane acrylate to the linear aliphatic epoxy acrylate is too low, the polycarbonate polyurethane acrylate content may be too low while the linear aliphatic epoxy acrylate content may be too high, thereby reducing the insulation performance of the coating. If the mass ratio of the polycarbonate polyurethane acrylate to the linear aliphatic epoxy acrylate is too high, the polycarbonate polyurethane acrylate content may be too high while the linear aliphatic epoxy acrylate content may be too low, thereby reducing the chemical corrosion resistance of the insulating coating and causing the insulating coating to age, decompose, and yellow under high temperature, high humidity, and prolonged use.

[0080] In one embodiment, the polycarbonate polyurethane acrylate has the general structural formula shown in structural formula (1):

[0081] Wherein, in structural formula (1), R1 is selected from a benzene ring or a C1-C6 substituted or unsubstituted alkyl group, and / or, R2 is selected from a substituted or unsubstituted cyclohexane group, and / or, R3 and R4 are each independently selected from a C1-C6 substituted or unsubstituted alkyl group, and / or, n is selected from an integer from 1 to 10, and / or, m is selected from an integer from 1 to 10.

[0082] In one embodiment, the polycarbonate polyurethane acrylate represented by structural formula (1) can be prepared by the following method:

[0083] S11. Add a diol compound having the structure shown in Formula 1 and dimethyl carbonate to a reaction vessel and mix thoroughly to obtain a first mixed solution. Calcium oxide is added to the first mixed solution as a catalyst, and the reaction is carried out at an ambient temperature of 100°C-160°C for 0.5-5 hours to obtain a polycarbonate diol shown in Formula 2. The molar ratio of the diol compound to dimethyl carbonate is (2-5):1, and the mass percentage of the catalyst in the first mixed solution is 0.1%-1%. The reaction formula is as follows:

[0084]

[0085] S12. Add acetone solvent and isocyanate compound to a reaction vessel, and allow the polycarbonate diol and isocyanate compound to continue to react at an ambient temperature of 60° C. to 90° C. for 6 h to 12 h to obtain the intermediate shown in Formula 3; wherein the molar ratio of the isocyanate compound to the diol compound is 2:1, and the reaction formula is as follows:

[0086]

[0087] S13. Adding an acrylate having a structure as shown in Formula 4 to a reaction vessel, allowing the intermediate and the acrylate to continue to react at an ambient temperature of 60° C. to 90° C. for 6 to 12 hours to obtain a polycarbonate-type polyurethane acrylate having structural formula (1); wherein the molar ratio of the acrylate to the diol compound is 2:1, and the reaction formula is as follows:

[0088]

[0089] In one embodiment, the linear aliphatic epoxy acrylate has the general structural formula shown in structural formula (2):

[0090]

[0091] Wherein, in structural formula (2), R1 is selected from C1-C10 substituted or unsubstituted linear or branched alkyl groups, and x is selected from integers of 1-6.

[0092] In this embodiment, the linear aliphatic epoxy acrylate maintains the high insulation performance of the epoxy resin itself; in addition, the linear aliphatic epoxy acrylate has a longer linear alkane chain segment, and the movement resistance of the linear alkane chain segment is small, which makes the linear aliphatic epoxy acrylate have good photocuring activity, improves the photocuring efficiency, and accelerates the cross-linking speed. At the same time, the longer linear alkane chain segment has a better hydrophobic effect, which can improve the hydrophobic properties of the insulating coating.

[0093] In one embodiment, the linear aliphatic epoxy acrylate represented by structural formula (2) can be prepared by the following method:

[0094] Acrylic acid and glycol diglycidyl ether having the structure shown in Formula 5 are added to a reaction vessel containing acetone solvent and mixed uniformly to obtain a mixed solution. Triethylamine is added to the mixed solution as a catalyst, and the mixture is reacted at an ambient temperature of 30°C to 100°C for 2 hours to obtain a linear aliphatic epoxy acrylate represented by structural formula (2). The molar ratio of acrylic acid to glycol diglycidyl ether is 2:1, and the mass percentage of the catalyst in the mixed solution is 0.05% to 1%. The reaction formula is as follows:

[0095]

[0096] In one embodiment, the photocurable ink further includes a pigment, a wetting agent, an inhibitor and / or a diluent.

[0097] In one embodiment, the wetting agent includes at least one of polyether-modified silicone and polyester-modified silicone. The wetting agent can improve the spreadability and anti-cratering properties of the photocurable ink.

[0098] In one embodiment, the mass percentage of the wetting agent in the photocurable ink is 0.5%-2.5%. Alternatively, the mass percentage of the wetting agent in the photocurable ink can be any one of 0.5%, 1%, 1.5%, 2%, 2.5%, etc., or a range between any two of them, without limitation herein.

[0099] In one embodiment, the polymerization inhibitor includes at least one of hydroquinone and p-methoxyphenol. The polymerization inhibitor can improve the storage stability of the photocurable ink.

[0100] In one embodiment, the mass percentage of the polymerization inhibitor in the photocurable ink is 0.1%-0.5%; alternatively, the mass percentage of the polymerization inhibitor in the photocurable ink can be any one of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc., or a range between any two of them, which is not limited here.

[0101] In one embodiment, the diluent includes at least one of isobornyl acrylate, isodecyl acrylate, lauryl acrylate, or hexadecyl acrylate.

[0102] In one embodiment, the mass percentage of the diluent in the photocurable ink is 4%-5%; alternatively, the mass percentage of the diluent in the photocurable ink can be any one of 4%, 4.2%, 4.6%, 4.8%, 5%, etc., or a range between any two of them, which is not limited here.

[0103] In one embodiment, the mass percentage of the pigment in the photocurable ink is 0.5%-1%. Alternatively, the mass percentage of the pigment in the photocurable ink can be any one of 0.5%, 0.6%, 0.7%, 0.8%, 1%, etc., or a range between any two thereof, without limitation herein.

[0104] In one embodiment, the particle size D50 of the pigment is ≤ 0.4 μm.

[0105] In one embodiment, the pigment includes at least one of phthalocyanine blue powder, phthalocyanine green powder, and titanium dioxide.

[0106] The present application also provides a method for preparing a photocurable ink, comprising: adding raw materials such as acrylic resin, active monomer, and initiator into a double planetary mixer, and dispersing them at 500 rpm to 1000 rpm for 0.5 to 1 hour to obtain the photocurable ink.

[0107] The present application also provides an insulating coating, which is formed by the photocurable ink as described above.

[0108] The present application also provides a battery housing comprising a main body and an insulating coating, the insulating coating being disposed on at least a portion of the outer surface of the main body and being formed from the photocurable ink described above. In this embodiment, the main body can be made of a material having a certain hardness and strength, such as copper, iron, aluminum, stainless steel, or an aluminum alloy, without limitation. The shape of the main body is also not limited, and can be a rectangular parallelepiped, cylindrical, hexagonal prism, or the like, without limitation.

[0109] The present application also provides a method for preparing a battery casing, comprising:

[0110] S01. Providing a main body of a battery casing;

[0111] S02, using the above-mentioned light-curable ink as a raw material, spraying an ink layer on at least a portion of the outer surface of the main body;

[0112] S03. The ink layer is cured by ultraviolet light to form an insulating coating, thereby obtaining a battery shell.

[0113] In this embodiment, a spraying process is adopted to spray a layer of ink on the surface of the main body, and ultraviolet light is used for photocuring. The ink layer can be cured in situ on the surface of the main body, which can improve the adhesion of the insulating coating on the main body. At the same time, the insulating coating has good flexibility and thermal shrinkage properties, and the insulating coating is not prone to brittle cracking and thermal shrinkage.

[0114] In one embodiment, the thickness of the ink layer is 50 μm-150 μm; optionally, the thickness of the ink layer can be any one of 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, etc. or a range between any two thereof, which is not limited here.

[0115] In one embodiment, the UV light source includes an LED lamp, and / or the wavelength of the UV light is 365 nm or 395 nm, and / or the curing time is 1 s-10 s.

[0116] The present application also provides a battery comprising the insulating coating described above, or comprising the battery casing described above, or a battery casing prepared using the method described above. In this embodiment, the type of battery is not limited, and the battery can be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery.

[0117] The present application will be further described below through specific examples.

[0118] Example 1

[0119] This embodiment provides a photocurable ink, which includes an acrylic resin, a reactive monomer, an initiator, a pigment, a wetting agent, an inhibitor, and a diluent; wherein:

[0120] The mass percentage of the initiator in the photocurable ink is 6.2%, and the initiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the absorption wavelength of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is 382 nm, the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the photocurable ink is 5%, the mass percentage of 2-chlorothioxanthone in the photocurable ink is 1%, and the mass percentage of ethylenediamine in the photocurable ink is 0.2%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0121] The mass percentage of acrylic resin in the light-curing ink is 45%, and the acrylic resin is composed of polycarbonate polyurethane acrylate and linear aliphatic epoxy acrylate, and the mass ratio between the polycarbonate polyurethane acrylate and the linear aliphatic epoxy acrylate is 0.5:1;

[0122] The mass percentage of the active monomer in the light-curable ink is 40.3%. The active monomer consists of isobornyl acrylate, 1,6-hexanediol diacrylate and trimethylolpropane triacrylate. The mass ratio of isobornyl acrylate, 1,6-hexanediol diacrylate and trimethylolpropane triacrylate is 5:1:0.3.

[0123] The mass percentage of the pigment in the light-curing ink is 0.7%, and the pigment is titanium dioxide;

[0124] The mass percentage of the wetting agent in the light-curing ink is 2.3%, and the wetting agent is polyether-modified silicone;

[0125] The mass percentage of the polymerization inhibitor in the light-curing ink is 0.5%, and the polymerization inhibitor is p-methoxyphenol;

[0126] The mass percentage of the diluent in the light-curing ink is 5%, and the diluent is lauryl acrylate.

[0127] Example 2

[0128] The main difference between Example 2 and Example 1 is that:

[0129] The mass percentage of the initiator in the light-curable ink is 8%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 2%, and the mass percentage of ethylenediamine in the light-curable ink is 1%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.5;

[0130] The mass percentage of diluent in light-curable ink is 3.2%;

[0131] The rest is the same as in Example 1.

[0132] Example 3

[0133] The main difference between Example 3 and Example 1 is that:

[0134] The mass percentage of the initiator in the light-curable ink is 8%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 2.5%, the mass percentage of ethylenediamine in the light-curable ink is 0.5%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0135] The mass percentage of diluent in light-curable ink is 3.2%;

[0136] The rest is the same as in Example 1.

[0137] Example 4

[0138] The main difference between Example 4 and Example 1 is that:

[0139] The mass percentage of the initiator in the light-curable ink is 3%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 2%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 0.83%, and the mass percentage of ethylenediamine in the light-curable ink is 0.17%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0140] The mass percentage of diluent in light-curable ink is 8.2%;

[0141] The rest is the same as in Example 1.

[0142] Example 5

[0143] The main difference between Example 5 and Example 1 is that:

[0144] The mass percentage of the initiator in the light-curable ink is 3%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 2%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 0.67%, and the mass percentage of ethylenediamine in the light-curable ink is 0.33%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.5;

[0145] The mass percentage of diluent in light-curable ink is 8.2%;

[0146] The rest is the same as in Example 1.

[0147] Example 6

[0148] The main difference between Example 6 and Example 1 is that:

[0149] The initiator consists of 2-hydroxy-2-methyl-1-phenylpropanone, isopropylthioxanthone and ethyl N,N-diphenylmethylcarboxylate; the mass percentage of 2-hydroxy-2-methyl-1-phenylpropanone in the light-curing ink is 5%, the mass percentage of isopropylthioxanthone in the light-curing ink is 1%, the mass percentage of ethyl N,N-diphenylmethylcarboxylate in the light-curing ink is 0.2%, and the mass ratio between isopropylthioxanthone and ethyl N,N-diphenylmethylcarboxylate is 1:0.2;

[0150] The rest is the same as in Example 1.

[0151] Example 7

[0152] The main difference between Example 7 and Example 1 is that:

[0153] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 0.8%, and the mass percentage of ethylenediamine in the light-curable ink is 0.4%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.5;

[0154] The rest is the same as in Example 1.

[0155] Example 8

[0156] The main difference between Example 8 and Example 1 is:

[0157] The mass ratio between isobornyl acrylate, 1,6-hexanediol diacrylate and trimethylolpropane triacrylate is 3:1:0.5;

[0158] The rest is the same as in Example 1.

[0159] Example 9

[0160] The main difference between Example 9 and Example 1 is that:

[0161] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 2%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 3.5%, and the mass percentage of ethylenediamine in the light-curable ink is 0.7%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0162] The rest is the same as in Example 1.

[0163] Example 10

[0164] The main difference between Example 10 and Example 1 is that:

[0165] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5.5%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 0.58%, and the mass percentage of ethylenediamine in the light-curable ink is 0.12%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0166] The rest is the same as in Example 1.

[0167] Example 11

[0168] The main differences between Example 11 and Example 1 are:

[0169] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 1.09%, and the mass percentage of ethylenediamine in the light-curable ink is 0.11%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.1;

[0170] The rest is the same as in Example 1.

[0171] Example 12

[0172] The main difference between Example 12 and Example 1 is that:

[0173] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 0.75%, and the mass percentage of ethylenediamine in the light-curable ink is 0.45%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.6;

[0174] The rest is the same as in Example 1.

[0175] Example 13

[0176] The main differences between Example 13 and Example 1 are:

[0177] The mass percentage of the initiator in the light-curable ink is 8.5%, and the initiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 6.85%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 1.375%, and the mass percentage of ethylenediamine in the light-curable ink is 0.275%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0178] The rest is the same as in Example 1.

[0179] Example 14

[0180] The main differences between Example 14 and Example 1 are:

[0181] The mass percentage of the initiator in the light-curable ink is 2.5%, and the initiator consists of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 2.0%, the mass percentage of 2-chlorothioxanthone in the light-curable ink is 0.42%, and the mass percentage of ethylenediamine in the light-curable ink is 0.08%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0182] The rest is the same as in Example 1.

[0183] Example 15

[0184] The main difference between Example 15 and Example 1 is that:

[0185] The mass ratio between isobornyl acrylate, 1,6-hexanediol diacrylate and trimethylolpropane triacrylate is 2:1:0.5;

[0186] The rest is the same as in Example 1.

[0187] Example 16

[0188] The main differences between Example 16 and Example 1 are:

[0189] The mass ratio between isobornyl acrylate, 1,6-hexanediol diacrylate and trimethylolpropane triacrylate is 5:1:0.2;

[0190] The rest is the same as in Example 1.

[0191] Comparative Example 1

[0192] The main difference between Comparative Example 1 and Example 1 is:

[0193] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2-chlorothioxanthone; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curable ink is 5%, and the mass percentage of 2-chlorothioxanthone in the light-curable ink is 1.2%;

[0194] The rest is the same as in Example 1.

[0195] Comparative Example 2

[0196] The main difference between Comparative Example 2 and Example 1 is:

[0197] The mass percentage of the initiator in the light-curable ink is 6.2%, and the initiator is composed of 2-chlorothioxanthone and ethylenediamine; the mass percentage of 2-chlorothioxanthone in the light-curable ink is 5.17%, the mass percentage of ethylenediamine in the light-curable ink is 1.03%, and the mass ratio between 2-chlorothioxanthone and ethylenediamine is 1:0.2;

[0198] The rest is the same as in Example 1.

[0199] Comparative Example 3

[0200] The main difference between Comparative Example 3 and Example 1 is that:

[0201] The mass percentage of the initiator in the light-curing ink is 6.2%, and the initiator is composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and ethylenediamine; the mass percentage of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the light-curing ink is 5%, and the mass percentage of ethylenediamine in the light-curing ink is 1.2%;

[0202] The rest is the same as in Example 1.

[0203] Test method:

[0204] The photocurable inks of Examples 1 to 16 and Comparative Examples 1 to 3 were sprayed on an aluminum sheet using an LED lamp as a light source with an ultraviolet light wavelength of 395 nm and a curing time of 8 s to obtain an insulating coating having a thickness of 100 μm.

[0205] (1) 100-grid adhesion test

[0206] Refer to the GB / T 9286-2021 method for testing. The insulating coatings obtained in Examples 1 to 16 and Comparative Examples 1 to 3 were adhered to the surface of a 150×100 mm aluminum plate and placed on a horizontal rigid plane. Use a grid knife to cut perpendicular to the sample, and all cuts should penetrate the surface of the substrate. Then, make the same number of cuts in a direction intersecting 90° with the original cutting line to form a grid line. Then, use a soft brush to sweep several times, apply transparent tape on top of the grid, flatten it, and then tear off the tape. Refer to the adhesion grading evaluation table for the adhesion of the bonded insulating coating. The test results are shown in Table 1.

[0207] (2) Shear strength test

[0208] The test was conducted according to GB / T 7124-2008. The test results are shown in Table 1.

[0209] (3) Insulation resistance test

[0210] The insulation performance of the insulating coatings obtained in Examples 1 to 16 and Comparative Examples 1 to 3 was tested using an insulation withstand voltage tester at a DC 1500 V test time of 60 seconds to measure insulation resistance. The test results are shown in Table 1.

[0211] (4) High temperature resistance test

[0212] The insulating coatings obtained in Examples 1 to 16 and Comparative Examples 1 to 3 were subjected to a high temperature resistance test at 130°C for 48 hours to observe whether the samples showed any abnormalities such as shrinkage, shedding, or cracking. The test results are shown in Table 1.

[0213] (5) Withstand voltage test

[0214] The insulating coatings obtained in Examples 1 to 16 and Comparative Examples 1 to 3 were subjected to a withstand voltage test using an insulation withstand voltage tester with a test condition of DC 4000 V, a test time of 60 s, and a leakage current of ≤ 0.1 mA. The test results are shown in Table 1.

[0215] (6) Aging test

[0216] The insulating coatings obtained in Examples 1 to 16 and Comparative Examples 1 to 3 were subjected to a voltage withstand test and aging treatment using a constant temperature and humidity chamber. The aging temperature was 85°C, the relative humidity was 85%, and the aging time was 2000 hours. The insulating coatings were observed for cracking and shearing after aging. The shear strength, adhesion, voltage withstand performance, and insulation resistance of the aged insulating coatings were also tested. The test results are shown in Table 2.

[0217] (7) Electrolyte resistance test

[0218] The insulating coatings obtained from Examples 1 to 16 and Comparative Examples 1 to 3 were immersed in D73 electrolyte at 25°C for 48 hours. After removal and drying, the insulating coatings were tested for their withstand voltage performance, insulation performance, and adhesion. The test results are shown in Table 3.

[0219] Table 1:

[0220]

[0221] Table 2:

[0222]

[0223] Table 3:

[0224]

[0225]

[0226] From the test results of the above-mentioned Examples 1 to 16 and Comparative Examples 1 to 3, it can be seen that the insulating coatings prepared in Examples 1 to 16 have a 100-grid adhesion of level 0 before aging treatment, and a shear strength greater than or equal to 9.1 MPa. The insulating coatings of the embodiments of the present application have good mechanical properties. The reason is that the photocurable ink includes an acrylic resin, an active monomer and an initiator. The initiator can promote the polymerization reaction between the active monomer and the acrylic resin to achieve the curing of the photocurable ink. The initiator includes a deep curing initiator, a shallow curing initiator and an amine co-initiator. The absorption wavelength of the deep curing initiator is 300nm-400nm. The deep curing initiator ensures that the deep curing initiator can also be effectively activated to generate free radicals in the deep area to achieve deep curing. The shallow curing initiator forms an excited state under light. The excited shallow curing initiator captures hydrogen atoms from the amine co-initiator to generate active free radicals and amine free radicals. The amine free radicals can react with oxygen to generate peroxyamine, improve the oxygen inhibition problem, and improve the surface curing effect of the coating. When the light-curing ink is cured, the surface curing and the bottom curing can be achieved at the same time, so that the shrinkage stress is evenly distributed, and the local stress concentration is reduced. At the same time, it ensures that the overall cross-linking of the insulating coating is uniform, thereby improving the overall strength of the coating and thus improving the mechanical properties of the insulating coating.

[0227] Comparison of Examples 1-8, 9, and 10 demonstrates that controlling the contents of the deep-layer curing initiator, shallow-layer curing initiator, and amine co-initiator within appropriate ranges can further improve the high-temperature resistance and aging performance of the insulating coating. This results in the insulating coating exhibiting good mechanical properties, insulation properties, voltage resistance, and high-temperature resistance both before and after aging treatment.

[0228] A comparison of Examples 1-8, 11, and 12 demonstrates that controlling the mass ratio of the shallow curing initiator to the amine co-initiator within an appropriate range can further improve the insulating coating's high-temperature resistance, aging performance, and electrolyte resistance. This results in the insulating coating exhibiting excellent mechanical properties, insulation performance, voltage resistance, and high-temperature resistance before, after, and after aging and electrolyte immersion.

[0229] A comparison of Examples 1-8, Example 13, and Example 14 demonstrates that controlling the mass percentage of the initiator in the photocurable ink within an appropriate range can further improve the insulating coating's high-temperature resistance, aging performance, and electrolyte resistance. This results in the insulating coating exhibiting excellent mechanical properties, insulation performance, voltage resistance, and high-temperature resistance before, after, and after aging and electrolyte immersion.

[0230] Comparison of Examples 1-8, 15, and 16 demonstrates that controlling the mass ratio of the monofunctional acrylate monomer, the difunctional acrylate monomer, and the multifunctional acrylate monomer within an appropriate range can further improve the insulating coating's high-temperature resistance, aging performance, and electrolyte resistance. This results in the insulating coating exhibiting excellent mechanical properties, insulation performance, voltage resistance, and high-temperature resistance before, after, and after aging and electrolyte immersion.

[0231] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A light-curing ink, characterized in that: include: Acrylic resin, reactive monomer and initiator; The initiator comprises a deep curing initiator, a shallow curing initiator and an amine auxiliary initiator. The absorption wavelength of the deep curing initiator is 300nm-400nm, and the shallow curing initiator comprises a thioxanthone compound.

2. The light-curable ink according to claim 1, characterized in that: The absorption wavelength of the initiator is 365nm or 395nm; and / or The mass percentage of the deep curing initiator in the photocurable ink is 2%-5%; and / or The sum of the mass of the shallow curing initiator and the amine co-initiator in the light-curable ink is 1% to 3% by mass; and / or The mass ratio between the shallow curing initiator and the amine co-initiator is 1:(0.2-0.5); and / or The mass percentage of the initiator in the photocurable ink is 3%-8%; and / or The mass percentage of the active monomer in the photocurable ink is 25%-50%; and / or The mass percentage of the acrylic resin in the light-curable ink is 40%-60%.

3. The light-curable ink according to claim 1 or 2, characterized in that: The deep curing initiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanocene, bis-2,6-difluoro-3-pyrrolphenyltitanocene, 2-hydroxy-2-methyl-1-phenylacetone, and 1-hydroxycyclohexylphenyl ketone; and / or The thioxanthone compound includes at least one of 2-chlorothioxanthone, isopropylthioxanthone and 2,4-diethylthioxanthone; and / or The amine co-initiator comprises at least one of an active amine and a tertiary amine benzoate; and / or The acrylic resin includes polycarbonate polyurethane acrylate and linear aliphatic epoxy acrylate; and / or The reactive monomers include monofunctional acrylate monomers, difunctional acrylate monomers and multifunctional acrylate monomers, and the functionality of the multifunctional acrylate monomers is greater than or equal to 3.

4. The light-curable ink according to claim 3, characterized in that: The active amine includes at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylamine, triethylamine, isophoronediamine, and 1,2-cyclohexanediamine; and / or The tertiary amine benzoate includes at least one of ethyl 4-(N,N-dimethylamino)benzoate, ethyl N,N-diphenylmethylcarboxylate, and 2-ethylhexyl N,N-dimethylbenzoate; and / or The monofunctional acrylate monomer includes at least one of isobornyl acrylate, isodecyl acrylate, lauryl acrylate or hexadecyl acrylate; and / or The bifunctional acrylate monomer includes at least one of 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and ethoxylated bisphenol A diacrylate; and / or The multifunctional acrylate monomer includes at least one of trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol penta / hexaacrylate, and tris(2-hydroxyethyl)isocyanurate triacrylate.

5. The light-curable ink according to claim 3, characterized in that: The mass ratio of the monofunctional acrylate monomer, the difunctional acrylate monomer and the multifunctional acrylate monomer is (3-5):1:(0.3-0.5); and / or The molecular weight of the polycarbonate polyurethane acrylate is 500-1200; and / or The molecular weight of the linear aliphatic epoxy acrylate is 500-1200; and / or The mass ratio between the polycarbonate polyurethane acrylate and the linear aliphatic epoxy acrylate is (0.5-3):1; and / or The polycarbonate polyurethane acrylate has a general structural formula shown in structural formula (1): Wherein, in structural formula (1), R1 is selected from a benzene ring or a C1-C6 substituted or unsubstituted alkyl group, and / or, R2 is selected from a substituted or unsubstituted cyclohexane group, and / or, R3 and R4 are each independently selected from a C1-C6 substituted or unsubstituted alkyl group, and / or, n is selected from an integer of 1-10, and / or, m is selected from an integer of 1-10; and / or The linear aliphatic epoxy acrylate has the general structural formula shown in structural formula (2): Wherein, in structural formula (2), R1 is selected from C1-C10 substituted or unsubstituted linear or branched alkyl groups, and / or x is selected from integers of 1-6.

6. The light-curable ink according to claim 1 or 2, characterized in that: The photocurable ink further includes a pigment, a wetting agent, an inhibitor and / or a diluent.

7. The light-curable ink according to claim 6, characterized in that: The wetting agent comprises at least one of polyether-modified silicone and polyester-modified silicone; and / or The polymerization inhibitor comprises at least one of hydroquinone and p-methoxyphenol; and / or The diluent includes at least one of isobornyl acrylate, isodecyl acrylate, lauryl acrylate or hexadecyl acrylate.

8. The light-curable ink according to claim 6, characterized in that: The mass percentage of the pigment in the light-curable ink is 0.5-1%; and / or The mass percentage of the wetting agent in the light-curable ink is 0.5-2.5%; and / or The mass percentage of the polymerization inhibitor in the photocurable ink is 0.1-0.5%; and / or The mass percentage of the diluent in the light-curable ink is 4-5%; and / or The particle size D50 of the pigment is ≤0.4 μm.

9. An insulating coating, characterized in that: The insulating coating is formed from the photocurable ink according to any one of claims 1 to 8.

10. A battery casing, characterized in that: include: Main body; An insulating coating layer is provided on at least a portion of the outer surface of the main body, and the insulating coating layer is formed by the photocurable ink according to any one of claims 1 to 8.

11. A method for preparing a battery shell, characterized in that: The preparation method of the battery shell includes: providing a main body portion of a battery housing; Using the light-curable ink according to any one of claims 1 to 8 as a raw material, spraying an ink layer on at least a portion of the outer surface of the main body; The ink layer is cured by ultraviolet light irradiation to form an insulating coating, thereby obtaining the battery shell.

12. The method for preparing a battery casing according to claim 11, wherein: The thickness of the ink layer is 50 μm-150 μm; and / or The light source of the ultraviolet light includes an LED lamp, and / or the wavelength of the ultraviolet light is 365nm or 395nm, and / or the curing time is 1s-10s.

13. A battery, characterized in that: The invention comprises the insulating coating according to claim 9, or comprises the battery shell according to claim 10, or is a battery shell prepared by the method according to claim 11 or 12.

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