UV insulating paint, preparation method and application

Abstract

The invention discloses a UV insulating coating as well as a preparation method and application thereof, and belongs to the technical field of coatings. The UV insulating paint comprises urethane acrylate, a monofunctional acrylic monomer, a trifunctional acrylic monomer, a leveling agent, a rheological additive, an inorganic filler, a photoinitiator, a toner, a dispersant and an adhesion promoter, the monofunctional acrylic monomer can provide good adhesion, flexibility and chemical resistance, and the trifunctional acrylic monomer can provide good adhesion, flexibility and chemical resistance; the trifunctional acrylic monomer is high in curing speed and can provide good weather resistance, water resistance and chemical resistance, and the urethane acrylate is the most important film-forming substance of the coating, so that the urethane acrylate, the monofunctional acrylic monomer and the trifunctional acrylic monomer are compounded and then have a synergistic effect with other components, and the coating has the advantages of high weather resistance, high water resistance and high chemical resistance. After being cured, the coating can have excellent insulating property and mechanical property at the same time, and the integrity and reliability of an insulating structure can still be kept under the impact of external force, so that lasting and stable insulation protection is provided for the battery.

Description

Technical Field

[0001] This application relates to the field of coating technology, and in particular to a UV insulating coating, its preparation method, and its application. Background Technology

[0002] Currently, to ensure electrical safety, the battery cell casings of new energy vehicles typically employ a blue film coating process. Blue film, as a common coating material, offers advantages such as low cost, good chemical corrosion resistance, and high tensile strength, providing basic protection for the battery cell. However, this coating method still has certain drawbacks in practical large-scale applications. For example, the adhesion strength between the blue film and the cell casing surface is limited, making it prone to interface peeling or cohesive failure under external mechanical stress or impact. This leads to the failure of the cell coating layer, not only reducing the structural integrity of the cell but also potentially causing a decrease in insulation performance or even a short circuit risk, posing significant safety hazards. Summary of the Invention

[0003] This application provides a UV insulating coating, its preparation method, and its application. After curing, the coating possesses both excellent insulating and mechanical properties, maintaining the integrity and reliability of its insulating structure even under external impact, thus providing long-lasting and stable insulation protection for the battery. The technical solution is as follows: On one hand, a UV insulating coating is provided, the UV insulating coating comprising the following components in parts by weight: The composition includes: 35-45 parts polyurethane acrylate, 30-40 parts monofunctional acrylic monomer, 5-15 parts trifunctional acrylic monomer, 0.1-0.5 parts leveling agent, 0.5-1 part rheology modifier, 5-10 parts inorganic filler, 3-10 parts photoinitiator, 1.5-3 parts colorant, 0.1-0.5 parts dispersant, and 1-5 parts adhesion promoter.

[0004] In one possible implementation, the polyurethane acrylate is selected from at least one of difunctional polyurethane-modified acrylic resins and trifunctional polyurethane-modified acrylic resins.

[0005] In another possible implementation, the viscosity of the difunctional polyurethane-modified acrylic resin and the trifunctional polyurethane-modified acrylic resin is 5000 mPa·s to 30000 mPa·s.

[0006] In another possible implementation, the bifunctional polyurethane-modified acrylic resin is selected from at least one of LuCure 5882 from Runao Chemical, CN981NS from Sartoma, 6123 from Changxing Chemical, and 61128 from Changxing Chemical. The trifunctional polyurethane-modified acrylic resin was selected from Sartoma's CN989NS and Changxing Chemical's DR-U268.

[0007] In another possible implementation, the monofunctional acrylic monomer is selected from at least one of isobornyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, N,N-dimethylacrylamide, lauryl acrylate, cyclotrimethylolpropane methyl acetal acrylate, 4-tert-butylcyclohexyl acrylate, acrylmorpholine, and 2-phenoxyethyl acrylate.

[0008] In another possible implementation, the trifunctional acrylic monomer is selected from at least one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, and pentaerythritol triacrylate.

[0009] In another possible implementation, the mass ratio of the monofunctional acrylic monomer to the trifunctional acrylic monomer is (5.5~7.2):1.

[0010] In another possible implementation, the photoinitiator is selected from at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl p-dimethylaminobenzoate, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthonone, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

[0011] In another possible implementation, the inorganic filler is selected from at least one of talc, sericite, and silica powder; The dispersant is selected from at least one of BYK-110, BYK-160, BYK-190 from BYK Chemicals, 755W from DIGIC Chemicals, and KMT-3003 from Corning Chemicals. The colorant is selected from at least one of titanium white, phthalocyanine blue, royal blue, dark blue, and phthalocyanine green; The rheology modifier is selected from at least one of BYK Garamite-7305 and BYK Garamite-1958 from BYK Chemicals and OPTIMA from Arkema. The leveling agent is selected from at least one of BYK-331 and BYK-333 from BYK Chemicals, FLOW-100 from Arkema, Glide 410 from DIGIC Chemicals, and Modaflow 9200C from ZX. The adhesion promoter is selected from at least one of Guangyi Chemical's 9051, Digo Chemical's TEGO 1300L, and Nippon Kayaku's PM-2.

[0012] On the other hand, a method for preparing a UV insulating coating is provided, wherein the UV insulating coating is as described in any of the above claims, and the preparation method includes: Color paste is prepared by using color powder and dispersant; Polyurethane acrylate, monofunctional acrylic monomer and trifunctional acrylic monomer are mixed evenly to obtain the first mixture. Add rheology modifiers and inorganic fillers to the first mixture, and mix thoroughly to obtain a second mixture; A photoinitiator, leveling agent, adhesion promoter and color paste are added to the second mixture and mixed evenly to obtain a UV insulating coating.

[0013] On the other hand, there is a method for using a UV insulating coating in the cell casing of a battery, the UV insulating coating being as described in any of the preceding claims.

[0014] This application provides a UV insulating coating comprising polyurethane acrylate, monofunctional acrylic monomers, trifunctional acrylic monomers, leveling agents, rheology modifiers, inorganic fillers, photoinitiators, colorants, dispersants, and adhesion promoters. The monofunctional acrylic monomers provide good adhesion, flexibility, and chemical resistance, while the trifunctional acrylic monomers cure quickly and provide good weather resistance, water resistance, and chemical resistance. Polyurethane acrylate is the primary film-forming substance in the coating. Therefore, by compounding polyurethane acrylate, monofunctional acrylic monomers, and trifunctional acrylic monomers, and then synergistically combining them with other components, the crosslinking density and strength of the coating film can be significantly improved. This allows the cured coating to possess both excellent insulation and mechanical properties, maintaining the integrity and reliability of the insulation structure even under external impact, thus providing durable and stable insulation protection for the battery. Detailed Implementation

[0015] To make the technical solution and advantages of this application clearer, the embodiments of this application will be described in further detail below.

[0016] On one hand, embodiments of this application provide a UV insulating coating, which comprises the following components in parts by weight: The composition includes: 35-45 parts polyurethane acrylate, 30-40 parts monofunctional acrylic monomer, 5-15 parts trifunctional acrylic monomer, 0.1-0.5 parts leveling agent, 0.5-1 part rheology modifier, 5-10 parts inorganic filler, 3-10 parts photoinitiator, 1.5-3 parts colorant, 0.1-0.5 parts dispersant, and 1-5 parts adhesion promoter.

[0017] This application provides a UV insulating coating comprising polyurethane acrylate, monofunctional acrylic monomers, trifunctional acrylic monomers, leveling agents, rheology modifiers, inorganic fillers, photoinitiators, colorants, dispersants, and adhesion promoters. The monofunctional acrylic monomers provide good adhesion, flexibility, and chemical resistance, while the trifunctional acrylic monomers cure quickly and provide good weather resistance, water resistance, and chemical resistance. Polyurethane acrylate is the primary film-forming substance in the coating. Therefore, by compounding polyurethane acrylate, monofunctional acrylic monomers, and trifunctional acrylic monomers, and then synergistically combining them with other components, the crosslinking density and strength of the coating film can be significantly improved. This allows the cured coating to possess both excellent insulation and mechanical properties, maintaining the integrity and reliability of the insulation structure even under external impact, thus providing durable and stable insulation protection for the battery.

[0018] For example, the mass fraction of polyurethane acrylate can be 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 44 parts, 45 parts, etc. Optionally, the mass fraction of polyurethane acrylate is 40 to 45 parts.

[0019] The photoinitiator can be present in quantities of 3, 4, 5, 6, 7, 8, 9, or 10 parts by weight. Optionally, the photoinitiator can be present in quantities of 5 to 10 parts by weight.

[0020] The mass fraction of the dispersant can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, etc. Optionally, the mass fraction of the dispersant is 0.3 parts to 0.5 parts.

[0021] The mass fractions of monofunctional acrylic monomers can be 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, and 40 parts, etc.; the mass fractions of trifunctional acrylic monomers can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 parts, etc.; the mass fractions of leveling agents can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, and 0.5 parts, etc.; and the rheology modifiers... The mass fractions can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, etc.; the mass fractions of inorganic fillers can be 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, etc.; the mass fractions of color powder can be 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, etc.; and the mass fractions of adhesion promoters can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0022] In the embodiments of this application, polyurethane acrylate provides the main properties of the UV insulating coating, participates in photocuring, and is the most important film-forming substance.

[0023] In one possible implementation, the polyurethane acrylate is selected from at least one of difunctional polyurethane-modified acrylic resins and trifunctional polyurethane-modified acrylic resins.

[0024] In the embodiments of this application, the viscosity of the difunctional polyurethane-modified acrylic resin and the trifunctional polyurethane-modified acrylic resin is 5000 mPa·s to 30000 mPa·s.

[0025] For example, the viscosity of bifunctional polyurethane-modified acrylic resin can be 5000 mPa·s, 8000 mPa·s, 10000 mPa·s, 15000 mPa·s, 20000 mPa·s, 25000 mPa·s, 30000 mPa·s, etc. The viscosity of trifunctional polyurethane-modified acrylic resin can be 5000 mPa·s, 8000 mPa·s, 10000 mPa·s, 15000 mPa·s, 20000 mPa·s, 25000 mPa·s, 30000 mPa·s, etc.

[0026] Bifunctional polyurethane-modified acrylic resins with viscosities ranging from 5000 mPa·s to 30000 mPa·s exhibit high reactivity, good toughness, and excellent weather resistance. Trifunctional polyurethane-modified acrylic resins with viscosities ranging from 5000 mPa·s to 30000 mPa·s exhibit higher hardness and better wear resistance.

[0027] In some embodiments, the difunctional polyurethane-modified acrylic resin satisfying the above viscosity range is selected from at least one of LuCure 5882 from Runao Chemical, CN981NS from Sartoma, 6123 from Changxing Chemical, and 61128 from Changxing Chemical; the trifunctional polyurethane-modified acrylic resin satisfying the above viscosity range is selected from CN989NS from Sartoma and DR-U268 from Changxing Chemical.

[0028] In the embodiments of this application, the aforementioned bifunctional polyurethane-modified acrylic resin provides flexibility and adhesion, enabling the coating film to possess excellent bending and impact resistance. The aforementioned trifunctional polyurethane-modified acrylic resin has a high degree of crosslinking and high reactivity, which can improve the curing rate of the coating film, giving it high hardness and good wear resistance.

[0029] In one possible implementation, when the polyurethane acrylate is selected from difunctional polyurethane-modified acrylic resin and trifunctional polyurethane-modified acrylic resin, the mass ratio of the difunctional polyurethane-modified acrylic resin to the trifunctional polyurethane-modified acrylic resin is (5~5.5):1.

[0030] For example, the mass ratio of difunctional polyurethane-modified acrylic resin to trifunctional polyurethane-modified acrylic resin can be 5:1, 5.1:1, 5.2:1, 5.3:1, 5.4:1, 5.5:1, etc.

[0031] In the embodiments of this application, a compound of difunctional polyurethane-modified acrylic resin and trifunctional polyurethane-modified acrylic resin is made, and the mass ratio of the two satisfies the above-mentioned range. This can make the paint film not only have high crosslinking density and hardness, but also improve its wear resistance. At the same time, the paint film has excellent adhesion and good flexibility, ensuring that the paint film is not easy to crack under external impact or deformation.

[0032] In the embodiments of this application, monofunctional acrylic monomers and trifunctional acrylic monomers can improve the crosslinking density and leveling properties of the coating film, improve the hardness and flexibility of the coating film, and also adjust the application performance.

[0033] In one possible implementation, the monofunctional acrylic monomer is selected from at least one of isobornyl acrylate (IBOA), hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), N,N-dimethylacrylamide (DMAA), lauryl acrylate (LA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), 4-tert-butylcyclohexyl acrylate (TBCHA), acrylmorpholine (ACMO), and 2-phenoxyethyl acrylate (PHEA).

[0034] In this implementation, isobornyl acrylate (IBOA) possesses high hardness, high reactivity, and low shrinkage, providing excellent wettability and adhesion, as well as outstanding abrasion resistance and scratch resistance. However, isobornyl acrylate monomer alone has poor flexibility and dilution ability, requiring combination with other monomers. IBOA can be selected from Changxing Chemical. Hydroxyethyl acrylate (HEA) has the advantages of high activity and strong adhesion, and can be selected from Taiyu Chemical. Hydroxyethyl methacrylate (HEMA) has high hardness and high durability, and can be selected from Guangyi Chemical. N,N-Dimethylacrylamide (DMAA) provides both high activity and dilution ability, as well as excellent flexibility and superior adhesion, and can be selected from Lankeluo. Lauryl acrylate (LA) has relatively low reactivity, but its long-chain structure provides excellent flexibility and hydrophobicity, and can be selected from Guangyi Chemical. Cyclotrimethylolpropane methyl acetal acrylate (CTFA) possesses high reactivity and low shrinkage, offering good adhesion, flexibility, abrasion resistance, and chemical resistance; it can be selected from Changxing Chemical. 4-tert-butylcyclohexyl acrylate (TBCHA) provides excellent mechanical properties as well as good water and chemical resistance; it can also be selected from Changxing Chemical. Acryloylmorpholine (ACMO) exhibits excellent dilution ability and superior resistance, offering excellent heat resistance and chemical resistance; it can be selected from Kejuxi. 2-Phenoxyethyl acrylate (PHEA) provides good adhesion and flexibility; it can be selected from Youming Chemical. In practical applications, the above components can be compounded and combined according to requirements.

[0035] In one possible implementation, the trifunctional acrylic monomer is selected from at least one of trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), ethoxylated trimethylolpropane triacrylate (TMP3EOTA), and pentaerythritol triacrylate (PETA).

[0036] In this implementation, trimethylolpropane triacrylate (TMPTA) and trimethylolpropane trimethacrylate (TMPTMA) can be selected from Changxing Chemical, and ethoxylated trimethylolpropane triacrylate (TMP3EOTA) and pentaerythritol triacrylate (PETA) can be selected from Youming Chemical.

[0037] In the embodiments of this application, the aforementioned trifunctional acrylic monomers exhibit fast curing speed, low skin irritation, and good weather resistance, water resistance, and chemical resistance. When used in combination with the aforementioned monofunctional acrylic monomers, they can significantly improve the crosslinking density and strength of the paint film, preventing phenomena such as paint peeling, cracking, and blistering under external impact. However, excessive use of trifunctional acrylic monomers can make the paint film too hard, leading to negative effects such as significantly reduced adhesion and brittleness. Therefore, the ratio of monofunctional to trifunctional acrylic monomers is crucial.

[0038] It should be noted that if the trifunctional acrylic monomer is selected solely from ethoxylated trimethylolpropane triacrylate (TMP3EOTA), the maximum amount of ethoxylated trimethylolpropane triacrylate (TMP3EOTA) can be 15 parts. If the trifunctional acrylic monomer is selected from one or more other trifunctional acrylic monomers, the amount of the other trifunctional acrylic monomers is 5 to 7 parts. Furthermore, if the trifunctional acrylic monomer is obtained by blending at least two components, the total amount of the trifunctional acrylic monomer should not exceed 8 parts. If it exceeds 8 parts, the trifunctional acrylic monomer is excessive, which will affect the performance of the coating.

[0039] In one possible implementation, the mass ratio of monofunctional acrylic monomer to trifunctional acrylic monomer is (5.5~7.2):1.

[0040] For example, the mass ratio of monofunctional acrylic monomer to trifunctional acrylic monomer can be 5.5:1, 5.8:1, 6:1, 6.1:1, 6.2:1, 6.3:1, 6.4:1, 6.5:1, 6.6:1, 6.7:1, 6.8:1, 6.9:1, 7:1, 7.1:1, 7.2:1, etc.

[0041] In the embodiments of this application, when the mass ratio of monofunctional acrylic monomers to trifunctional acrylic monomers is within the aforementioned range, the entire coating system not only possesses excellent application performance but also combines the superior properties of high-functionality and low-functionality resins and monomers. This results in a paint film with high fullness and hardness while maintaining a certain degree of flexibility. Furthermore, the cured paint film exhibits minimal shrinkage and stress, is less prone to cracking, and demonstrates excellent adhesion, along with superior insulation and chemical resistance. When the mass ratio of monofunctional acrylic monomers to trifunctional acrylic monomers is less than the aforementioned range, although the elongation of the paint film is high, insufficient crosslinking density leads to cracking during impact testing. When the mass ratio of monofunctional acrylic monomers to trifunctional acrylic monomers exceeds this range, the system becomes over-crosslinked, the paint film becomes brittle, and its mechanical properties, such as bending and impact resistance, are poor.

[0042] It should be noted that if the trifunctional acrylic monomer is selected from one or more monomers other than ethoxylated trimethylolpropane triacrylate (TMP3EOTA), or if the trifunctional acrylic monomer is selected from ethoxylated trimethylolpropane triacrylate (TMP3EOTA) and one or more other monomers, then the mass ratio of the monofunctional acrylic monomer to the trifunctional acrylic monomer is in the range of (5.5~7.2):1. If the trifunctional acrylic monomer is selected only from ethoxylated trimethylolpropane triacrylate (TMP3EOTA), then the mass ratio of the monofunctional acrylic monomer to the trifunctional acrylic monomer can be 2:1 to 8:1.

[0043] In one possible implementation, the photoinitiator is selected from at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (819), ethyl p-dimethylaminobenzoate (EDB), 1-hydroxycyclohexylphenyl ketone (184), 2-isopropylthioxanthone (ITX), 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO), and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (907).

[0044] In this implementation, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (819) and ethyl p-dimethylaminobenzoate (EDB) can be selected from IGM, 1-hydroxycyclohexylphenyl ketone (184) and 2-isopropylthioxanthone (ITX) can be selected from Guangyi Chemical, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO) can be selected from Shanghai Feikai, and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (907) can be selected from Youming Chemical.

[0045] In the embodiments of this application, the photoinitiator can absorb radiation energy, stimulate chemical reactions, and initiate polymerization. However, adding too little photoinitiator will result in incomplete curing of the formulation components, while adding too much will leave unreacted photoinitiator residues, leading to a decrease in the physical properties of the coating film.

[0046] In addition, due to the high thickness of the cured film, both deep curing and surface drying must be considered. Different combinations of solid-drying photoinitiators and surface-drying photoinitiators are used depending on the curing light source. For example, when using an iron lamp for curing, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and 1-hydroxycyclohexylphenyl ketone (184) can be compounded in a mass ratio of (3~4):1.

[0047] For example, the mass ratio of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) to 1-hydroxycyclohexylphenyl ketone (184) can be 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, etc.

[0048] In one possible implementation, the inorganic filler is selected from at least one of talc, sericite, and silica powder.

[0049] The dispersant is selected from at least one of BYK-110, BYK-160, BYK-190 from BYK Chemicals, 755W from DIGIC Chemicals, and KMT-3003 from Corning Chemicals.

[0050] The pigment is selected from at least one of titanium white, phthalocyanine blue, royal blue, dark blue, and phthalocyanine green.

[0051] The rheology modifier is selected from at least one of BYK Garamite-7305 and BYK Garamite-1958 from BYK Chemicals and OPTIMA from Arkema.

[0052] The leveling agent is selected from at least one of BYK-331 and BYK-333 from BYK Chemicals, FLOW-100 from Arkema, Glide410 from DIGIC Chemicals, and Modaflow 9200C from ZX Chemicals.

[0053] The adhesion promoter is selected from at least one of Guangyi Chemical's 9051, Digo Chemical's TEGO 1300L, and Nippon Kayaku's PM-2.

[0054] In this implementation, the particle size of the inorganic filler is between 3000 mesh and 5000 mesh. Adding inorganic fillers can significantly reduce coating costs, effectively improve the mechanical strength and adhesion of the paint film, thicken and prevent settling, and adjust application performance. Furthermore, inorganic fillers can provide excellent insulation, enhancing the chemical resistance and weather resistance of the paint film.

[0055] Dispersants can enhance color performance, fully utilize the tinting and hiding power of pigments, and form a smoother, more even paint film surface, achieving a high-gloss effect. They can also improve storage stability and optimize rheological properties. At the same viscosity, using a highly efficient dispersant allows for the addition of more pigments, reducing costs or improving performance. Furthermore, it can increase production efficiency, shorten grinding and dispersion time, and save energy.

[0056] For pigments, pigments can be selected from at least one of titanium dioxide, phthalocyanine blue, and phthalocyanine green. In practical applications, pigments can be selected or compounded according to the required color.

[0057] It should be noted that the pigment needs to be pre-dispersed in the monomer with a dispersant to prepare a color paste, thereby reducing the difficulty of sample preparation. The monomer can be isobornyl acrylate (IBOA), and the mass ratio of pigment to monomer can be (1~1.5):1.

[0058] For example, the mass ratio of pigment to monomer can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc.

[0059] Rheology modifiers can be organic clays, such as BYK Garamite-7305, which is an organically modified layered silicate with a multi-particle morphology, making it easier to disperse. In liquids, it forms a weak three-dimensional network structure. In a static state, this low-shear network structure is stable, providing high viscosity, effectively locking in pigment particles, preventing sedimentation and water separation. During application, the high-shear network structure is temporarily disrupted, causing a rapid decrease in viscosity, making the coating easier to apply and level. After application, the shear disappears, the three-dimensional network structure quickly recovers, and the viscosity rebounds, thus producing an anti-sagging effect.

[0060] The leveling agent can be a polyether-modified polydimethylsiloxane leveling agent, such as BYK-331 and BYK-333. The leveling agent can eliminate various surface defects by migrating to the interface, reducing and homogenizing the surface tension, and ultimately giving the paint film a high degree of smoothness.

[0061] Adhesion promoters can be phosphate ester-based adhesion promoters, such as Guangyi Chemical's 9051 and Nippon Kayaku's PM-2. These types of adhesion promoters can significantly improve the adhesion of coatings to inorganic substrates such as metals and glass, and effectively inhibit moisture and corrosive ions (such as Cl-) by forming a stable phosphate layer. - It penetrates into the metal interface, enhancing corrosion resistance.

[0062] It should be noted that the blue film coating process in the relevant technology has poor adaptability to automated equipment. During the coating process, uneven bonding can easily lead to problems such as bubbles, bulges, and curling edges, which affect product consistency and yield.

[0063] The UV insulating coating provided in this application can replace the traditional blue film coating process. This coating combines monofunctional and trifunctional acrylic monomers, and by optimizing the type and ratio of photoinitiators, it exhibits excellent insulation properties and mechanical strength after UV curing. It maintains the integrity and reliability of the insulation structure even under external impact, thus providing long-lasting and stable insulation protection for the battery. The coating formed by this material exhibits excellent adhesion to metals and good chemical and weather resistance. It maintains excellent performance after aging tests, ensuring the long-term reliability of the coating's protection. Furthermore, this coating can be applied using UV spraying technology, making it suitable for fully automated production lines, significantly improving coating efficiency and reducing production costs.

[0064] On the other hand, embodiments of this application provide a method for preparing a UV insulating coating, the method comprising: Step 1: Prepare color paste using color powder and dispersant.

[0065] Before preparing the color paste, first check the reaction vessel (such as a material tank or stainless steel reactor) to ensure that the inner wall and stirring device are clean. Then, add the color powder, dispersant and isobornyl acrylate (IBOA) to the reaction vessel, and mix the color powder, dispersant and isobornyl acrylate (IBOA) in the preset ratio. Stir at a speed of 300 r / min to 500 r / min for 10 min to 15 min until it is evenly dispersed. After that, transfer the color paste to a suitable sealed container and leave at least 1 / 3 of the space. Add glass beads at a ratio of 1:1.2 and then grind it with a shaker until the fineness is <25 μm. Filter it and set it aside for later use.

[0066] For example, the rotation speed in step 1 can be 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc., and the stirring time can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0067] Step 2: Mix polyurethane acrylate, monofunctional acrylic monomer and trifunctional acrylic monomer evenly to obtain the first mixture.

[0068] Add polyurethane acrylate, monofunctional acrylic monomer and trifunctional acrylic monomer to the reaction vessel, and stir at 500 r / min to 600 r / min for 5 min to 10 min. After the polyurethane acrylate is initially dissolved, adjust the stirring speed to 800 r / min to 1000 r / min. After the polyurethane acrylate is fully dissolved, reduce the stirring speed to 300 r / min to 500 r / min.

[0069] For example, in step 2, the initial rotation speed can be 500 r / min, 520 r / min, 550 r / min, 580 r / min, 600 r / min, etc., the stirring time can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc., the adjusted rotation speed can be 800 r / min, 850 r / min, 900 r / min, 950 r / min, 1000 r / min, etc., and the reduced rotation speed can be 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc.

[0070] Step 3: Add rheology modifier and inorganic filler to the first mixture, and mix evenly to obtain the second mixture.

[0071] While stirring, add rheology modifiers and inorganic fillers to the first mixture, and gradually increase the rotation speed to 1000 r / min to 1500 r / min. Disperse at high speed for more than 30 minutes. When the fineness drops below 25 μm, reduce the rotation speed to 300 r / min to 500 r / min.

[0072] In step 3, the increased rotational speed can be 1000 r / min, 1100 r / min, 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, etc., and the decreased rotational speed can be 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc.

[0073] Step 4: Add photoinitiator, leveling agent, adhesion promoter and color paste to the second mixture, mix evenly to obtain UV insulating coating.

[0074] While stirring, add the photoinitiator, leveling agent, adhesion promoter and color paste prepared in step 1 to the second mixture. Adjust the speed to 500 r / min to 800 r / min and stir for 10 min to 15 min. Stop stirring when the photoinitiator is completely dissolved and the fineness is less than 25 μm. After filtration, the UV insulating coating is obtained.

[0075] In step 4, the adjusted rotation speed can be 500 r / min, 600 r / min, 700 r / min, 800 r / min, etc., and the stirring time can be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, etc.

[0076] On the other hand, this application also provides the application of a UV insulating coating in the cell casing of a battery.

[0077] The material of the battery cell casing can be set and changed as needed, and no specific limitation is made. For example, if the battery cell casing is a 3003 aluminum plate substrate, the UV insulating coating provided in this application can be sprayed onto the surface of the 3003 aluminum plate substrate. The construction parameters are as follows: spraying is carried out under the conditions of 15℃~30℃ and 40%RH~70%RH relative humidity. After the first coat is applied, it is leveled at 50℃ for 1 minute, and then pre-cured by a 395nm LED with a curing energy of 3000mJ / cm². 2 ~5000mJ / cm 2 After the second coat is applied, it is leveled at 50°C for 1 minute, then pre-cured using a 395nm LED with a curing energy of 3000mJ / cm². 2 ~5000mJ / cm 2 It was then transferred to an iron lamp for final curing, with a curing energy of 5000 mJ / cm². 2 ~6000mJ / cm 2 The construction was completed. The first and second coats were each about 50μm thick, and the total film thickness after spraying was 100μm~120μm.

[0078] The spraying environment temperature can be 15℃, 18℃, 20℃, 22℃, 25℃, 28℃, 30℃, etc., and the relative humidity can be 40%, 50%, 60%, 70%, etc. The curing energy corresponding to the first and second spraying coats can be 3000mJ / cm². 2 3500mJ / cm 2 4000mJ / cm 2 4500mJ / cm 2 5000mJ / cm 2 The final curing energy can be 5000 mJ / cm². 2 5200mJ / cm 2 5500mJ / cm 2 5800mJ / cm 2 6000mJ / cm 2 The total film thickness can be 100μm, 102μm, 105μm, 108μm, 110μm, 112μm, 115μm, 118μm, 120μm, etc.

[0079] To make the technical solution and advantages of this application clearer, they will be described in detail below through specific embodiments.

[0080] In the following specific embodiments, operations without specified conditions are performed under standard conditions or conditions recommended by the manufacturer. Raw materials without specified manufacturers and specifications are all commercially available products.

[0081] Example 1 Example 1 provides a UV insulating coating, which can be prepared by the following method: (1) Color paste is prepared by using color powder and dispersant.

[0082] Add 2.61 parts titanium dioxide, 0.29 parts phthalocyanine blue, 0.1 parts phthalocyanine green, 0.3 parts BYK110 from BYK Chemical, and 2 parts IBOA to the reaction vessel. Stir at 400 r / min for 15 min to disperse evenly. Transfer the color paste to a sealed container, leaving at least 1 / 3 of the space. Add glass beads at a ratio of 1:1.2 and grind with a shaker until the fineness is <25 μm. Filter and set aside for later use.

[0083] (2) Add 35.79 parts of LuCure5882 from Runao Chemical, 6.80 parts of CN989NS from Sartoma, 2.44 parts of TBCHA from Changxing Chemical, 4.39 parts of HEMA from Guangyi Chemical, 1.71 parts of HEA from Taiyu Chemical, 27.39 parts of IBOA from Changxing Chemical, 1.01 parts of TMPTA from Changxing Chemical and 5.07 parts of TMP3EOTA from Youming Chemical to the reaction vessel. Stir at 550 r / min for 8 min. After LuCure5882 and CN989NS have initially dissolved, adjust the speed to 900 r / min. After LuCure5882 and CN989NS have fully dissolved, reduce the speed to 400 r / min to obtain the first mixture.

[0084] (3) While stirring, add 0.51 parts of BYK Garamite-7305 and 5.07 parts of 3000 mesh mica powder to the first mixture, and increase the speed to 1200 r / min for high-speed dispersion for 40 min. When the fineness drops below 25 μm, reduce the speed to 400 r / min to obtain the second mixture.

[0085] (4) While stirring, add 1.27 parts of IGM photoinitiator TPO, 3.80 parts of Guangyi Chemical photoinitiator 184, 0.20 parts of BYK-331 from BYK Chemical, 1.01 parts of Guangyi Chemical 9051 and 3.55 parts of color paste to the second mixture. Adjust the speed to 600 r / min and stir for 10 min. Stop stirring when the photoinitiator TPO and photoinitiator 184 are completely dissolved and the fineness is less than 25 μm. After filtration, the UV insulating coating is obtained.

[0086] The composition of this coating can also be found in Table 1.

[0087]

[0088] Example 2 Example 2 provides a UV insulating coating. The composition of the coating can be found in Table 2, and its preparation method can be found in Example 1, which will not be repeated here.

[0089]

[0090] Example 3 Example 3 provides a UV insulating coating. The composition of the coating can be found in Table 3, and its preparation method can be found in Example 1, which will not be repeated here.

[0091]

[0092] Example 4 Example 4 provides a UV insulating coating. The composition of the coating can be found in Table 4, and its preparation method can be found in Example 1, which will not be repeated here.

[0093]

[0094] Example 5 Example 5 provides a UV insulating coating. The composition of the coating can be found in Table 5, and its preparation method can be found in Example 1, which will not be repeated here.

[0095]

[0096] Comparative Example 1 Comparative Example 1 provides a UV insulating coating. The composition of the coating can be found in Table 6, and its preparation method can be found in Example 1, which will not be repeated here.

[0097]

[0098] Comparative Example 2 Comparative Example 2 provides a UV insulating coating. The composition of the coating can be found in Table 7, and its preparation method can be found in Example 1, which will not be repeated here.

[0099]

[0100] Comparative Example 3 Comparative Example 3 provides a UV insulating coating. The composition of the coating can be found in Table 8, and its preparation method can be found in Example 1, which will not be repeated here.

[0101]

[0102] Comparative Example 4 Comparative Example 4 provides a UV insulating coating. The composition of the coating can be found in Table 9, and its preparation method can be found in Example 1, which will not be repeated here.

[0103]

[0104] Comparative Example 5 Comparative Example 5 provides a UV insulating coating. The composition of the coating is shown in Table 10, and its preparation method is shown in Example 1, which will not be repeated here.

[0105]

[0106] This application tested the UV insulating coatings prepared in Examples 1-5 and Comparative Examples 1-5. The relevant test items are as follows, and the test results can be found in Table 11.

[0107] (1) Insulation resistance test: The test was conducted using an intelligent safety comprehensive analyzer. The test environment was 25℃ and the humidity was 40%RH~70%RH. The contact area between the paint film test surface and the electrode may be large. The DC 1000V delay time was 60s. The measured insulation resistance must be ≥1GΩ.

[0108] (2) Pressure resistance test: The test was conducted using an intelligent safety comprehensive analyzer (DC 1000V with a 60s delay). The test environment was 25℃ and the humidity was 40%RH~70%RH. The contact area between the paint film test surface and the electrode may be large. The DC 5000V test was conducted with a 60s delay and a voltage rise time of <1s. The test was repeated 25 times, and the measured withstand voltage leakage current was <0.1mA.

[0109] (3) Adhesion test: The adhesion should be tested according to GB / T 9286-1998, the adhesion test method for paint coatings (cross-cut adhesion test), and the adhesion should be ≤1 level.

[0110] (4) Flexibility test: The test was conducted according to GB / T 6742-2007 Paint and Varnish Bending Test (Cylindrical Shaft). A 25mm diameter shaft was bent 180° without the paint film peeling off or cracking, meeting the adhesion grade of 0~1 and the insulation withstand voltage performance requirements.

[0111] (5) Impact resistance test: The test was conducted according to GB / T 1732-1993 (≥5J) Test Method for Impact Resistance of Paint Film. Under 1x and 4x magnification, there were no defects such as paint peeling or cracks, which met the above insulation withstand voltage requirements.

[0112] (6) Electrolyte resistance test: The electrolyte is lithium iron phosphate electrolyte. At 25℃, the electrolyte is dripped onto the paint film surface and left to stand for 2 hours. After wiping dry, it is tested for at least 2 hours and at most 4 hours. There should be no bubbling or wrinkling, and slight discoloration and loss of gloss are allowed. It meets the adhesion level 0~1 requirements and the insulation withstand voltage performance requirements.

[0113] (7) Water resistance test: According to GB / T 1733-1993, the water resistance of the coating film is tested at 60℃ for 168 hours. The test plate is then left to stand for at least 2 hours and at most 24 hours. No bubbling or wrinkling is allowed, and slight discoloration or loss of gloss is permitted. The coating film meets the adhesion grade of 0 to 1 and the insulation withstand voltage performance requirements.

[0114]

[0115]

[0116] As can be seen from Table 11, the UV insulating coatings prepared in Examples 1-5 exhibit excellent overall performance, possessing both excellent insulation and mechanical properties, as well as good chemical resistance. Examples 1, 2, 3, and 5 all show good overall performance. Example 4 showed slight whitening in appearance during the water resistance test, but its performance was normal. Example 4 showed excellent surface drying after curing, but due to significant yellowing of the ITX coating, the film appearance changed from blue to green.

[0117] This application combines difunctional polyurethane-modified acrylic resin and trifunctional polyurethane-modified acrylic resin, which gives the coating film good flexibility, high crosslinking density, and fast curing speed, resulting in excellent adhesion of the coating film on 3003 aluminum.

[0118] Furthermore, by using different monofunctional and trifunctional acrylic monomers in appropriate proportions, the paint film avoids both insufficient crosslinking density leading to low tensile strength and poor impact resistance, and excessive crosslinking density resulting in brittleness and a significant reduction in mechanical properties. The blending of different monomers also improves the chemical resistance of the paint film, allowing for continued use in harsh environments. Therefore, the blending of monofunctional and trifunctional acrylic monomers can simultaneously impart excellent application properties to the coating and enhance the insulation and mechanical properties of the paint film.

[0119] The UV insulating coatings prepared in Comparative Examples 1-5 all exhibited significant defects. In Comparative Example 1, with a large ratio of difunctional polyurethane-modified acrylic resin to trifunctional polyurethane-modified acrylic resin, the crosslinking density of the coating film was insufficient. Although the film exhibited good flexibility, its impact resistance was poor. In Comparative Example 2, without the use of trifunctional acrylic monomers, the crosslinking strength of the coating film was insufficient, resulting in poor flexibility. While it could withstand a 180° bend with a 32mm curvature diameter shaft, it cracked under a 180° bend with a 25mm curvature diameter shaft, and its impact resistance was also poor. In Comparative Example 3, with an excessive amount of trifunctional acrylic monomers, the system underwent over-crosslinking, resulting in an extremely brittle coating film. Its adhesion dropped to level 5, and its bending and impact resistance were extremely poor, leading to severe cracking and paint peeling. In Comparative Example 4, with a suboptimal photoinitiator ratio, the surface drying of the coating film was poor, and curing was incomplete, significantly reducing its insulation performance. In Comparative Example 5, using only difunctional polyurethane-modified acrylic resin, the system exhibited poor insulation performance.

[0120] In summary, the UV insulating coating prepared in this application forms a coating with excellent insulation performance, good adhesion, excellent flexibility and impact resistance, and excellent comprehensive performance such as water and chemical resistance.

[0121] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A UV insulating coating, characterized in that, The UV insulating coating comprises the following components in parts by weight: The composition includes: 35-45 parts polyurethane acrylate, 30-40 parts monofunctional acrylic monomer, 5-15 parts trifunctional acrylic monomer, 0.1-0.5 parts leveling agent, 0.5-1 part rheology modifier, 5-10 parts inorganic filler, 3-10 parts photoinitiator, 1.5-3 parts colorant, 0.1-0.5 parts dispersant, and 1-5 parts adhesion promoter.

2. The UV insulating coating according to claim 1, characterized in that, The polyurethane acrylate is selected from at least one of difunctional polyurethane-modified acrylic resin and trifunctional polyurethane-modified acrylic resin.

3. The UV insulating coating according to claim 2, characterized in that, The viscosity of the difunctional polyurethane-modified acrylic resin and the trifunctional polyurethane-modified acrylic resin is 5000 mPa·s to 30000 mPa·s.

4. The UV insulating coating according to claim 3, characterized in that, The bifunctional polyurethane-modified acrylic resin is selected from at least one of LuCure 5882 from Runao Chemical, CN981NS from Sartoma, 6123 from Changxing Chemical, and 61128 from Changxing Chemical. The trifunctional polyurethane-modified acrylic resin was selected from Sartoma's CN989NS and Changxing Chemical's DR-U268.

5. The UV insulating coating according to claim 1, characterized in that, The monofunctional acrylic monomer is selected from at least one of isobornyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, N,N-dimethylacrylamide, lauryl acrylate, cyclotrimethylolpropane methyl acetal acrylate, 4-tert-butylcyclohexyl acrylate, acrylmorpholine, and 2-phenoxyethyl acrylate.

6. The UV insulating coating according to claim 1, characterized in that, The trifunctional acrylic monomer is selected from at least one of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, and pentaerythritol triacrylate.

7. The UV insulating coating according to claim 1, characterized in that, The mass ratio of the monofunctional acrylic monomer to the trifunctional acrylic monomer is (5.5~7.2):

1.

8. The UV insulating coating according to claim 1, characterized in that, The photoinitiator is selected from at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl p-dimethylaminobenzoate, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthonone, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

9. The UV insulating coating according to claim 1, characterized in that, The inorganic filler is selected from at least one of talc, sericite, and silica powder; The dispersant is selected from at least one of BYK-110, BYK-160, BYK-190 from BYK Chemicals, 755W from DIGIC Chemicals, and KMT-3003 from Corning Chemicals. The colorant is selected from at least one of titanium white, phthalocyanine blue, royal blue, dark blue, and phthalocyanine green; The rheology modifier is selected from at least one of BYK Garamite-7305 and BYK Garamite-1958 from BYK Chemicals and OPTIMA from Arkema. The leveling agent is selected from at least one of BYK-331 and BYK-333 from BYK Chemicals, FLOW-100 from Arkema, Glide410 from DIGIC Chemicals, and Modaflow 9200C from ZX Chemicals. The adhesion promoter is selected from at least one of Guangyi Chemical's 9051, Digo Chemical's TEGO 1300L, and Nippon Kayaku's PM-2.

10. A method for preparing a UV insulating coating, characterized in that, The UV insulating coating is as described in any one of claims 1 to 9, and the preparation method includes: Color paste is prepared by using color powder and dispersant; Polyurethane acrylate, monofunctional acrylic monomer and trifunctional acrylic monomer are mixed evenly to obtain the first mixture. Add rheology modifiers and inorganic fillers to the first mixture, and mix thoroughly to obtain a second mixture; A photoinitiator, leveling agent, adhesion promoter and color paste are added to the second mixture and mixed evenly to obtain a UV insulating coating.

11. The application of a UV insulating coating in the cell casing of a battery, characterized in that, The UV insulating coating is as described in any one of claims 1 to 9.

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