Preparation method and application of a micro-particleized stable uv insulating inkjet

Abstract

The application discloses a preparation method and application of a micro-particle stable UV insulating inkjet, relates to the technical field of UV insulating inkjet preparation, and comprises the following steps: mixing, stirring and uniformly mixing low-molecular-weight hyperbranched modified acrylic resin, acrylic ester monomer, a UV auxiliary agent and a self-made color paste, so as to obtain the UV insulating inkjet which can be sprayed, wherein the components are composed of the following components in parts by weight: 20-40 parts of the low-molecular-weight hyperbranched modified acrylic resin, 50-70 parts of the acrylic ester monomer, 2-10 parts of the UV auxiliary agent and 1-7 parts of the self-made color paste. The application realizes dynamic adjustment of the inkjet formula by fusing various modified acrylic ester resins and acrylic ester monomers with different functionalities, and by cooperating with the high-efficiency UV auxiliary agent and the self-made color paste. The customized scheme can accurately regulate the functional characteristics of the insulating inkjet according to specific application requirements, and widens the use scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of UV insulating inkjet, in particular to a preparation method of micronized and stable UV insulating inkjet and application thereof. Background Art

[0002] In the rapidly developing new energy vehicle sector, ensuring absolute battery system safety is the cornerstone of the industry's progress. Driven by technological advancements, electric vehicles based on 800V high-voltage platforms have become the new era's trend, placing unprecedented demands on the insulation coating of the battery cell—its core component. Faced with this challenge, the limitations of traditional blue film technology are gradually becoming apparent, with issues such as complex processes, high costs, and poor environmental adaptability becoming increasingly prominent.

[0003] To this end, the present invention provides a method for preparing micronized, stable UV insulating inkjet ink for new energy vehicles and its application, providing a micronized, low-viscosity, and long-lasting stable UV insulating inkjet ink. By integrating multiple modified acrylate resins, acrylate monomers with different functional groups, high-efficiency UV additives, and self-made color pastes, and precisely adjusting the components and ratios, the UV insulating inkjet function can be customized to meet different application requirements. This formula is designed specifically for 800V new energy vehicle batteries and combines characteristics such as resistance to boiling, acid and alkali, electrolyte, impact, and salt spray, high adhesion, high shear, high insulation, and rapid curing. This overcomes the shortcomings of existing technologies and provides a safer, more reliable, efficient, durable, and cost-optimized solution for the new energy vehicle industry.

[0004] Furthermore, to achieve higher clarity and precision, we selected a nozzle with a nozzle diameter of 450nm for the coating spraying operation. Particle size that is too large can not only cause nozzle clogging but also lead to unnecessary equipment costs. Existing UV dielectric inkjet products on the market face bottlenecks: either the particle size is difficult to reduce to below 300nm, or this fine particle size cannot be maintained continuously under high temperature conditions of 60°C. Therefore, we propose a method for preparing micronized and stable UV dielectric inkjet and its application. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a micronized and stable UV insulating inkjet and its application, so as to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a method for preparing a micronized, stable UV insulating inkjet and its application. This inkjet utilizes a carefully selected and scientifically formulated combination of various modified acrylate resins, monofunctional, difunctional, trifunctional, tetrafunctional, and hexafunctional acrylate monomers, supplemented with colorants and a variety of high-efficiency UV additives. After rigorous testing under extreme conditions, it demonstrates excellent insulating properties and adhesion. The technical solutions of the present invention are primarily based on the following innovations:

[0007] First, the addition of modified acrylate resin, as the core component of the present invention, provides the coating with excellent comprehensive performance due to its unique molecular structure and chemical properties. Specifically:

[0008] The addition of medium- to low-molecular-weight hyperbranched acrylated polyurethanes significantly increases the cure speed of UV insulating coatings. Their low viscosity makes them particularly suitable for inkjet coatings. First, due to their low molecular weight, these PUAs possess more reactive groups, such as double bonds, which react rapidly with photoinitiators under UV light, forming a dense network structure that accelerates coating cure. Second, the hyperbranched structure is a key factor in increasing cure speed and reducing viscosity. The highly branched molecular chains of hyperbranched polymers reduce intermolecular entanglement, allowing reactants to more easily contact and react. Furthermore, the increased intermolecular spacing enhances fluidity, resulting in lower viscosity. Low viscosity is particularly important in inkjet coatings, as it ensures smooth inkjet flow through the nozzle of the inkjet device, resulting in a uniform, fine coating and minimizing the occurrence of bubbles and defects. Furthermore, low viscosity helps the inkjet spread better on the substrate during the spraying process, improving coating adhesion and smoothness. Therefore, adding low molecular weight hyperbranched acrylate polyurethane to UV insulation coating not only improves the curing speed, but also enhances its applicability in inkjet applications, providing better coating solutions for fields such as new energy vehicles.

[0009] Adding anhydride-modified epoxy acrylates can significantly improve the acid, alkali, and electrolyte resistance of UV insulating coatings. This is likely due to the increased crosslinking density between epoxy acrylate molecules caused by anhydride modification, forming a more stable three-dimensional network structure. This strengthened crosslinking reduces the coating's permeability to acids, alkalis, and electrolytes, thereby enhancing the coating's chemical stability and corrosion resistance, making it more effective in protecting substrates in corrosive environments. Furthermore, anhydride modification may introduce functional groups with high polarity and reactivity, further enhancing the coating's chemical resistance.

[0010] Adding polyether polyols as the backbone of an acrylated polyurethane coating significantly enhances its impact resistance and toughness. Due to its exceptional flexibility and abrasion resistance, polyether polyol-based polyurethanes, when added to a UV-curable coating, not only maintain excellent insulation properties but also enhance the coating's elasticity and crack resistance, effectively absorbing and dispersing external impacts and reducing the risk of damage to the battery cells. The resulting coating rapidly cures under UV light, providing a tough, mechanically resistant protective layer that comprehensively protects the battery cells.

[0011] Adding low-molecular-weight diol-chain-extended acrylate urethane oligomers can enhance the coating's electrical performance by improving its microstructure. The low-molecular-weight diol acts as a chain extender, aiding the formation of a polyurethane network, resulting in a coating with a lower dielectric constant and dielectric loss, while also improving the coating's thermal stability and mechanical strength. The optimized coating rapidly cures under UV light, forming a thin film with excellent insulation properties that effectively prevents current leakage, thereby improving overall electrical performance and ensuring the safe operation of the battery cell or circuit.

[0012] Secondly, the complementary advantages of multifunctional monomers are leveraged: Acrylate monomers of varying functionalities each play a unique role in the UV curing process, achieving complementary advantages. Monofunctional acrylate monomers impart excellent flexibility and fluidity to the coating, ensuring uniform coverage and close adhesion to the substrate. Hexafunctional acrylate monomers significantly increase the coating's crosslinking density and hardness, thereby enhancing its abrasion and chemical resistance. This optimal combination of monomers imparts a coating with both flexibility and rigidity, as well as exceptional durability.

[0013] Again, in the homemade color paste, this patent carefully selected phthalocyanine blue as the core blue color powder in the color paste, and cleverly combined it with other key ingredients - aldehyde ketone resin A81, acrylate polyurethane with polyether polyol as the main chain (especially PPG600 is selected for synthesis), acrylate, titanium dioxide and efficient wetting and dispersing agents. Aldehyde ketone resin A81, with its excellent wetting properties and rich aldehyde and ketone functional groups, forms a stable coordination bond with the N atom in the phthalocyanine blue molecule, effectively inhibiting the agglomeration of phthalocyanine blue molecules. At the same time, the polyether polyol acrylate polyurethane synthesized based on PPG600, with its unique cage structure, can tightly wrap the phthalocyanine blue particles, avoiding mutual collision and aggregation between particles, and significantly improving the stability of the color powder in the ink. This discovery not only optimizes the formula of the ink, but also further verifies the unique advantages of PPG600 in the synthesis of high-performance acrylate polyurethane. The introduction of benzyl acrylate, leveraging its similar benzene ring structure to that of phthalocyanine blue molecules, promotes uniform dispersion of toner particles, enhancing the ink's color rendering and stability. The addition of inorganic powder not only provides a solid support for the coating but also further improves the ink's insulating electrical properties. Furthermore, the amphiphilic nature of the wetting and dispersing agent enables it to bridge the gap between phthalocyanine blue molecules and the ink's non-polar molecules, promoting a good bond between the toner and the ink matrix. The synergistic effect of these components creates a stable and efficient ink system, ensuring that the toner particles remain stably dispersed even at 60°C, meeting the stringent requirements of high-precision inkjet printing over the long term.

[0014] Furthermore, UV additives play an indispensable role in this invention. Photoinitiators, the starting substance for the curing reaction, have a direct impact on the coating's curing rate and degree. Additives such as leveling agents and defoamers help improve inkjet application performance and the coating's surface quality. Antioxidants and UV absorbers effectively extend the coating's lifespan and protect it from environmental damage. Through the rational selection and proportioning of these additives, their synergistic effects are fully realized, significantly improving the coating's overall performance.

[0015] Finally, scientific formulation design and precise process control are also core technologies of this invention. By studying the interaction mechanisms between the various components, combined with advanced formulation design and process control methods, the proportions and addition order of the components can be precisely controlled to optimize the inkjet composition and performance. Furthermore, strict control of process parameters such as temperature, humidity, and stirring rate during the production process ensures stable and consistent inkjet quality. This scientific formulation design and process control strategy provides solid technical support for the development of high-performance, high-reliability UV dielectric inkjet products.

[0016] In summary, the present invention achieves a low-viscosity UV inkjet ink that simultaneously meets the requirements of boil-proofing, acid and alkali resistance, electrolyte resistance, impact resistance, salt spray resistance, high adhesion, high shear strength, high insulation, fast curing, and inkjet printing suitability through the precise blending of modified acrylate resins, various types of functional acrylate monomers, and various UV additives, supplemented by scientific formulation design and process control. This is the basis for the completion of the present invention.

[0017] The low molecular weight hyperbranched modified acrylic resin includes low molecular weight hyperbranched acrylate polyurethane, anhydride modified epoxy acrylate, acrylate polyurethane with polyether polyol as main chain, and acrylate polyurethane oligomer with low molecular weight polyol chain extension.

[0018] The low molecular weight hyperbranched acrylate polyurethane is obtained by hydroxyl addition capping of a "core molecule" and a hydroxyl-containing acrylate monomer in the presence of a catalyst I;

[0019] The anhydride-modified epoxy acrylate is obtained by an addition polymerization reaction between glycidyl methacrylate and anhydride in the presence of catalyst II;

[0020] The acrylate polyurethane with polyether polyol as the main chain is obtained by adding hydroxyl groups to the polyether polyol and the acrylate monomer containing hydroxyl groups in the presence of a catalyst I;

[0021] The low molecular weight polyol chain-extended acrylate polyurethane oligomer is obtained by adding hydroxyl groups to diisocyanate and a low molecular weight polyol and a hydroxyl-containing acrylate monomer in the presence of catalyst I;

[0022] The self-made color paste is obtained by uniformly mixing and stirring blue pigment, inorganic filler, grinding resin, acrylate monomer and wetting dispersant.

[0023] Furthermore, the preparation method of the low molecular weight hyperbranched acrylate polyurethane is as follows:

[0024] Place diisocyanate, polymerization inhibitor, and catalyst I in a three-necked flask, stir evenly, and heat to 40-70°C. Slowly dropwise add the core molecule, previously dissolved in tetrahydrofuran. Raise the temperature to 65-85°C and maintain the reaction for 3-5 hours, until the residual -NCO content in the product reaches the theoretical -NCO content, to obtain polyurethane intermediate I.

[0025] The polyurethane intermediate I is heated to 60-80°C, and a hydroxyl-containing acrylate end-capping agent is slowly added dropwise. The temperature is controlled at 80-100°C, and the reaction is continued until the residual -NCO content of the product is less than 5‰. The reaction is then stopped to obtain a low molecular weight hyperbranched acrylate polyurethane.

[0026] Preferably, the diisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate. The preferred types of diisocyanates described herein should be consistent with those in the preceding section to ensure consistency in material properties and synergistic effects across patent embodiments.

[0027] Preferably, the polymerization inhibitor is selected from p-hydroxyanisole, polymerization inhibitor 510, polymerization inhibitor ST-1, methyl hydroquinone, butyl hydroquinone, tert-butyl catechol, and 2,6-di-tert-butyl-p-cresol. The preferred types of polymerization inhibitors described herein should be consistent with those in the preceding section to ensure consistency in material properties and synergistic effects among the patent embodiments.

[0028] Preferably, the catalyst I is selected from at least one of diethyltin dilaurate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin oxide, dibutyltin octoate, zinc diacetate, zinc dilaurate, zinc dioctoate, bismuth neodecanoate, and bismuth isooctanoate. The preferred type of catalyst I described herein should be consistent with the aforementioned section to ensure consistency in material properties and synergistic effects between patent embodiments.

[0029] Preferably, the core molecule is selected from at least one of pentaerythritol and dipentaerythritol.

[0030] Preferably, the hydroxyl-containing acrylate end-capping agent is selected from at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and pentaerythritol triacrylate. The preferred type of hydroxyl-containing acrylate end-capping agent described herein should be consistent with the aforementioned section to ensure consistency in material properties and synergistic effects across patent examples.

[0031] Furthermore, the preparation method of the anhydride-modified epoxy acrylate is as follows:

[0032] Mix a liquid anhydride or a solid anhydride dissolved in an acrylate diluent monomer with Catalyst II and a polymerization inhibitor, heat to 60-80°C, and slowly add glycidyl methacrylate dropwise. After the addition is complete, raise the temperature to 80-100°C for reaction. The product epoxy ester is measured to be less than 1 mol / kg and has an acid value of less than 2 mg KOH / g, indicating an anhydride-modified epoxy acrylate.

[0033] Preferably, the acid anhydride is selected from at least one of phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride and tetrahydrophthalic anhydride.

[0034] Preferably, the catalyst II is at least one selected from benzyltriethylammonium chloride, trioctylmethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium bromide, tetrapentylammonium bromide, and triphenylphosphine, more preferably at least one selected from tetrabutylammonium bromide and triphenylphosphine.

[0035] Furthermore, the preparation method of the acrylic polyurethane with polyether polyol as the main chain is as follows:

[0036] Heat the polyether polyol to 110°C and, while ensuring the container is sealed, reduce the negative pressure to 0.2 MPa and maintain for 1 hour. Once the water removal operation is complete, set aside. Heat the diisocyanate to 50-70°C and slowly add the catalyst I and the dehydrated polyether polyol dropwise. Heat to 50-70°C and maintain the temperature for 3-5 hours until the residual -NCO content in the product reaches the theoretical -NCO content, yielding polyurethane intermediate I.

[0037] After adding catalyst I dropwise to the polyurethane intermediate I, the temperature is raised to 80-100°C, and a hydroxyl-containing acrylate end-capping agent is added. The reaction is continued until the residual -NCO content of the product is less than 5‰, and the reaction is stopped to obtain an acrylate polyurethane with a polyether polyol as the main chain.

[0038] Preferably, the polyether polyol is selected from polypropylene glycol (PPG) and polyethylene glycol (PEG), specifically at least one of PPG200, PPG400, PPG600, PEG200, PEG300, PEG400, and PEG600.

[0039] Furthermore, the preparation method of the low molecular weight polyol chain-extended acrylate polyurethane oligomer is as follows:

[0040] The hydroxyl-containing acrylate end-capping agent, chain extender, polymerization inhibitor, and catalyst I are mixed evenly and then heated to 50-70°C. Diisocyanate is slowly added dropwise and the temperature is raised to 80-110°C. The reaction is carried out until the residual -NCO content of the product is less than 5‰. The reaction is then stopped to obtain a low-molecular-weight polyol-chain-extended acrylate polyurethane oligomer.

[0041] Preferably, the chain extender is selected from at least one of ethylene glycol, propylene glycol, 1,4-butanediol, 2-methyl-1,3-propanediol, diethylene glycol, 1,6-hexanediol, trimethylolpropane, and glycerol.

[0042] Furthermore, the acrylate monomer is selected from at least one of tetrahydrofuranyl acrylate, isobornyl acrylate, 2-ethylhexyl acrylate, glycidyl methacrylate, lauryl acrylate, stearyl acrylate, benzyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, ethoxyethoxyethyl acrylate, β-carboxyethyl acrylate, 1,6-hexanediol diacrylate, trihydroxymethylcyclohexyl acrylate, dipentaerythritol hexaacrylate, propoxylated glycerol triacrylate, dicyclopentenyl acrylate, 2-methylbutyl acrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, tripropylene glycol diacrylate, tripropylene glycol diacrylate, ethoxypentaerythritol tetraacrylate, propoxylated neopentyl glycol diacrylate, ethylene glycol dimethacrylate, 2-phenoxyethyl acrylate, polyethylene glycol o-phenylphenyl ether acrylate, ethoxylated trimethylolpropane triacrylate, and acryloylmorpholine.

[0043] Furthermore, the UV auxiliary agent is selected from at least one of a photoinitiator, a leveling agent, a defoaming agent or an adhesion promoter.

[0044] Preferably, the photoinitiator is selected from at least one of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylphenyl ketone, and 2-isopropylthioxanthone.

[0045] Preferably, the leveling agent is selected from at least one of BYK333, BYK346, BYK077 BYK358N (BYK Chemicals, Germany), TEGOGlide 425, TEGO Flow 300, and TEGO Glide 100 (TEGO, Germany).

[0046] Preferably, the defoaming agent is selected from at least one of TEGO Airex 920, TEGO Airex 900 (Germany), BYK-020, BYK-085 (Germany BYK Chemical), and Lencolo 2108 (Lan Kelu).

[0047] Preferably, the adhesion promoter is selected from at least one of Sipomer PAM-100 (Sauver), LTH (Germany Digo), SYG-PM-2 (Xinghengtai Chemical Technology Co., Ltd.), and Lencolo 4051 (Lan Kelu).

[0048] Furthermore, the homemade color paste preparation method is as described above, wherein the homemade color paste is uniformly mixed with blue color powder, inorganic filler, grinding resin, acrylate monomer, and wetting dispersant, transferred to a color paste grinder, ground with 0.2 mm zirconia beads to a particle size of ≤300 nm, and the material is filtered to obtain the homemade color paste.

[0049] Preferably, the blue pigment is selected from BASF K7090 phthalocyanine blue pigment.

[0050] Preferably, the inorganic filler is selected from at least one of silicon micropowder, talc, aluminum hydroxide and titanium dioxide.

[0051] Preferably, the grinding resin is selected from at least one of L-8430 (Lan Kelu), BR-1122 (Mitsubishi, Japan), aldehyde-ketone resin A81, and the above-mentioned acrylic polyurethane with polyether polyol as the main chain. More preferably, aldehyde-ketone resin A81 and acrylic polyurethane with polyether polyol as the main chain are selected.

[0052] Preferably, the wetting and dispersing agent is selected from at least one of TEGO Dispers 685 (from Germany) and BYK-9150 (from Germany).

[0053] This invention provides a process for preparing a low-viscosity, micronized, and long-lasting UV insulating inkjet ink. By uniformly mixing and stirring various modified acrylate resins, monofunctional, difunctional, trifunctional, tetrafunctional, and hexafunctional acrylate monomers, a high-efficiency UV additive, and a custom-made colorant, the resulting low-viscosity, micronized, and long-lasting UV insulating inkjet ink is achieved. Because this process does not involve any chemical reactions, the order in which the raw materials are added is not strictly limited; the mixing steps can be adjusted flexibly based on personal preference or production practices, as long as all components are fully incorporated.

[0054] Preferably, the process for preparing micronized, low-viscosity, and long-lasting stable UV insulating inkjet ink comprises the following steps:

[0055] S1: Evenly mix acrylate monomer, UV additive, and pre-synthesized modified acrylate resin oligomer to obtain varnish;

[0056] S2 adds the homemade color paste to the varnish obtained in S1, stirs until the mixture is uniform, and obtains pre-UV insulating inkjet.

[0057] S3 filters the pre-UV insulating inkjet through a 0.3μm pore size filter paper to test whether the inkjet particle size is ≤300nm. If not, refilter until the particle size meets the requirements. This will produce a low-viscosity, micronized, and long-lasting stable UV insulating inkjet.

[0058] The present invention provides a UV insulating coating product, wherein the low-viscosity, micronized and long-lasting stable UV insulating inkjet proposed in the first aspect is sprayed once on a 10*10 cm aluminum alloy sheet, and after two photocuring steps, a sample product with a coating thickness of 80-120 μm is obtained.

[0059] Preferably, the spraying conditions are: the ink temperature is set to 60° C., the spraying flow rate is 40 mL / min, and the distance between the nozzle and the spraying surface is 10 cm.

[0060] Preferably, the curing intensity is 600-800 mj / cm2 for the first curing, and the curing time is controlled within 1-3 seconds. The second curing intensity is controlled within 1000-1500 mj / cm2, and the single curing time is 6-10 seconds.

[0061] The present invention also provides the application of low-viscosity, micronized and long-lasting stable UV insulating inkjet in the insulation protection of the outer packaging of power battery cells.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. Customized Formulation Innovation: This invention combines a variety of modified acrylate resins with acrylate monomers of varying functionalities, along with a high-efficiency UV additive and custom-made colorants, to achieve dynamic adjustment of inkjet formulations. This customized solution allows precise control of the functional properties of insulating inkjet inks based on specific application requirements, broadening their application scenarios.

[0064] 2. High-Performance Comprehensive Properties: The low-viscosity, micronized, and long-lasting UV insulation inkjet formula meets the high insulation standards of 800V new energy vehicle cells while demonstrating exceptional overall durability, including resistance to boiling water, acid and alkali corrosion, electrolyte erosion, salt spray, impact, high adhesion, high shear strength, and rapid curing. This innovation effectively fills a market gap and contributes to a safer, more reliable, efficient, durable, and cost-effective solution for the new energy vehicle industry.

[0065] 3. Advanced Process Optimization: The unique value of this invention lies in its low viscosity (≤30cps) and micronization technology (particle size ≤300nm). This combination not only ensures smooth application in existing inkjet equipment, avoiding the additional cost of hardware upgrades, but also promotes high printing precision and surface smoothness, significantly reducing the risk of nozzle clogging. Furthermore, by simplifying the production process and improving material utilization, this invention successfully improves production efficiency and reduces costs, demonstrating significant advantages over traditional blue film technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 The synthetic route diagram of the low molecular weight hyperbranched acrylate polyurethane of the present invention;

[0067] Figure 2 The synthetic route diagram of the acrylic polyurethane with polyether polyol as the main chain of the present invention. DETAILED DESCRIPTION

[0068] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0069] Preparation Example 1

[0070] This preparation example provides a method for preparing a low molecular weight hyperbranched acrylate polyurethane:

[0071] Place 66 parts of isophorone diisocyanate, 0.4 parts of p-hydroxyanisole, and 0.1 parts of dibutyltin diacetate in a three-necked flask, stir thoroughly, and heat to 60°C. Slowly dropwise add 12.7 parts of dipentaerythritol, previously dissolved in 25 parts of tetrahydrofuran. Raise the temperature to 75°C and maintain the reaction for 3-5 hours, until the residual -NCO content in the product reaches the theoretical -NCO content, to obtain polyurethane intermediate I.

[0072] Heat polyurethane intermediate I to 75°C, then slowly add 100 parts of pentaerythritol triacrylate dropwise. Maintain the temperature at 90°C and continue the reaction until the residual -NCO content in the product is less than 5‰. The reaction is then terminated to yield a low-molecular-weight hyperbranched acrylate polyurethane. For clarity and flow, "Resin 1" will be used as the abbreviation below.

[0073] In a preferred embodiment, the synthesis path of the low molecular weight hyperbranched acrylate polyurethane is as follows Figure 1 shown.

[0074] Preparation Example 2

[0075] This preparation example provides a method for preparing an anhydride-modified epoxy acrylate:

[0076] Mix 50 parts of methyltetrahydrobenzene, 0.1 parts of tetrabutylammonium bromide, and 0.5 parts of 2,6-di-tert-butyl-p-cresol, and heat to 70°C. Slowly add 80 parts of glycidyl methacrylate dropwise. After the addition is complete, raise the temperature to 85°C for reaction. The product epoxy ester is measured to have a concentration of less than 1 mol / kg and an acid value of less than 2 mg KOH / g, indicating an anhydride-modified epoxy acrylate. This will be referred to as "Resin 2" below.

[0077] Preparation Example 3

[0078] This preparation example provides a method for preparing an acrylic polyurethane with a polyether polyol as the main chain:

[0079] Heat 60 parts of PPG600 polyol to 110°C. While ensuring the container is sealed, reduce the negative pressure to 0.2 MPa and maintain for 1 hour. After dehydration, set aside. Heat 39 parts of dicyclohexylmethane diisocyanate to 70°C and slowly add 0.06 parts of dioctyltin diacetate and the dehydrated PPG600 dropwise. Heat to 70°C and maintain the temperature until the residual -NCO content in the product reaches the theoretical -NCO content, yielding polyurethane intermediate II.

[0080] After adding 0.06 parts of dioctyltin diacetate dropwise to polyurethane intermediate II, the temperature was raised to 85°C and 21.6 parts of hydroxypropyl methacrylate was added. The reaction was continued until the residual -NCO content of the product was less than 5‰. The reaction was then terminated to obtain an acrylate polyurethane with a polyether polyol backbone. This will be referred to as "resin 3" below.

[0081] In a preferred embodiment, the synthesis path of the acrylic polyurethane with polyether polyol as the main chain is as follows: Figure 2 shown.

[0082] Preparation Example 4

[0083] This preparation example provides a method for preparing a low molecular weight polyol chain-extended acrylate polyurethane oligomer:

[0084] Mix 60 parts of hydroxyethyl methacrylate, 9.5 parts of 1,6-hexanediol, 0.3 parts of p-hydroxyanisole, and 0.1 parts of zinc diacetate. Heat to 55°C, then slowly add 39 parts of hexamethylene diisocyanate dropwise. Heat to 90°C and allow to react until the residual -NCO content of the product is less than 5‰. The reaction is then terminated to yield a low-molecular-weight polyol-extended acrylate polyurethane oligomer. This will be referred to as "Resin 4" below.

[0085] Preparation Example 5

[0086] This preparation example provides a method for preparing a homemade color paste:

[0087] Mix 30 parts of blue color powder, 2 parts of titanium dioxide, 15 parts of aldehyde-ketone resin A81, 20 parts of acrylic polyurethane with polyether polyol as the main chain (synthesized by PPG600), 80 parts of benzyl acrylate, and 3 parts of BYK9150, stir evenly, transfer to a color paste grinder, grind with 0.2 mm zirconium oxide beads to a particle size of ≤300 nm, filter the material, and obtain a homemade color paste.

[0088] Example 1

[0089] 20 parts of benzyl acrylate, 15 parts of ethoxyethoxyethyl acrylate, 8 parts of ethylene glycol dimethacrylate, 8 parts of trimethylolcyclohexyl acrylate, 6 parts of ethoxypentaerythritol tetraacrylate, 5 parts of isobornyl acrylate, 5 parts of tris(2-hydroxyethyl)isocyanurate triacrylate, 3 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, 3 parts of 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, 1.8 parts of LTH, 0.1 part of BYK333, 0.1 part of TEGO Airex 900, 3 parts of resin 1 prepared in Preparation Example 1, 5 parts of resin 2 prepared in Preparation Example 2, 8 parts of resin 3 prepared in Preparation Example 3, 9 parts of resin 4 prepared in Preparation Example 4, and 5 parts of the homemade color paste prepared in Preparation Example 5 were added to a reactor and stirred at high speed until completely mixed to obtain a low-viscosity, microparticulated, and long-lasting stable UV insulating inkjet.

[0090] Example 2

[0091] 18 parts of isobornyl acrylate, 12 parts of 2-phenoxyethyl acrylate, 8 parts of polyethylene glycol o-phenylphenyl ether acrylate, 8 parts of tetrahydrofuran acrylate, 7 parts of ethoxylated trimethylolpropane triacrylate, 5 parts of 4-acryloylmorpholine, 4 parts of (2-hydroxyethyl)isocyanuric acid triacrylate, 3 parts of 2-isopropylthioxanthone, 3 parts of 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, 1.8 parts of SYG-PM-2, 0.1 parts of TEGO Glide100, 0.1 parts of BYK-020, 3 parts of resin 1 prepared in Preparation Example 1, 8 parts of resin 2 prepared in Preparation Example 2, 7 parts of resin 3 prepared in Preparation Example 3, 12 parts of resin 4 prepared in Preparation Example 4, and 5 parts of the homemade color paste prepared in Preparation Example 5 were added to a reactor and stirred at high speed until completely mixed to obtain a low-viscosity, micronized and long-lasting stable UV insulating inkjet.

[0092] Example 3

[0093] 20 parts of dicyclopentenyl acrylate, 15 parts of ethoxyethoxyethyl acrylate, 10 parts of tripropylene glycol diacrylate, 8 parts of dipropylene glycol diacrylate, 8 parts of tetrahydrofuran acrylate, 5 parts of propoxylated neopentyl glycol diacrylate, 5 parts of tripropylene glycol diacrylate, 4 parts of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, 3 parts of 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, 1.8 parts of Lencolo 4051, 0.1 part of BYK346, 0.1 part of Lencolo 2108, 5 parts of resin 1 prepared in Preparation Example 1, 5 parts of resin 2 prepared in Preparation Example 2, 6 parts of resin 3 prepared in Preparation Example 3, 4 parts of resin 4 prepared in Preparation Example 4, and 5 parts of the homemade color paste prepared in Preparation Example 5 were added to a reactor and stirred at high speed until completely mixed to obtain a low-viscosity, microparticulated, long-lasting and stable UV insulating inkjet.

[0094] Comparative Example 1

[0095] The difference from Example 1 is that the resin composition is adjusted: 25 parts of Resin 1 are added alone, and Resin 2, Resin 3, and Resin 4 are not added. The types and amounts of other components in the formula remain unchanged.

[0096] Comparative Example 2

[0097] The difference from Example 1 is that the resin composition is adjusted: 25 parts of Resin 2 is added alone, and Resin 1, Resin 3, and Resin 4 are not added. The types and amounts of other components in the formula remain unchanged.

[0098] Comparative Example 3

[0099] The difference from Example 1 is that the resin composition is adjusted: 25 parts of Resin 3 is added alone, and Resin 1, Resin 2, and Resin 4 are not added. The types and amounts of other components in the formula remain unchanged.

[0100] Comparative Example 4

[0101] The difference from Example 1 is that the resin composition is adjusted: 25 parts of Resin 4 is added alone, and Resin 1, Resin 2, and Resin 3 are not added. The types and amounts of other components in the formula remain unchanged.

[0102] Comparative Example 5

[0103] The difference from Example 1 is that no adhesion promoter, leveling agent, or defoamer is added. That is, the added amounts of LTH, BYK333, and TEGO Airex 900 are zero, and the types and amounts of other components in the formula remain unchanged.

[0104] Comparative Example 6

[0105] The difference from Example 1 is that the components of the color paste are adjusted, and the amount of color paste added remains unchanged. That is, the homemade color paste in Preparation Example 5 is changed to the following component ratio:

[0106] 30 parts of blue color powder, 2 parts of titanium dioxide, 80 parts of lauryl acrylate, 40 parts of tris(2-hydroxyethyl)isocyanurate triacrylate, and 3 parts of BYK9150 were mixed and stirred evenly, transferred to a color paste grinder, and ground with 0.2 mm zirconium oxide beads to a particle size of ≤300 nm. The material was filtered to obtain a homemade color paste.

[0107] Experimental example

[0108] The UV insulating inkjet was sprayed on a 10*10 cm aluminum alloy sheet at one time, and after two light curings, a sample product with a coating thickness of 100±5 μm was obtained.

[0109] The spraying conditions are as follows: the ink temperature is set to 50° C., the spraying flow rate is 0.15 kg / m 2 , and the distance between the nozzle and the spraying surface is 10 cm.

[0110] The curing conditions are as follows: the first curing intensity is 600 mj / cm2, the curing time is 2 s, and the second curing intensity is controlled at 1200 mj / cm2, and the curing time is 8 s.

[0111] Test Case

[0112] The above embodiments and comparative examples were tested as follows. The test conditions and test results are as follows:

[0113] 1. Odor: Evaluate the inkjet sample using the olfactory method in a non-interference environment. If there is no pungent odor or foreign taste, it meets the standard.

[0114] 2. Viscosity: UV inkjet viscosity was measured using a rotational viscometer at room temperature (23±2° C.) and relative humidity (50±5%) according to GB / T 1723-1993.

[0115] 3. Particle Size: UV inkjet particle size is measured using a laser particle size analyzer in accordance with GB / T 1724-2019. D97 ≤ 300nm meets inkjet technical requirements.

[0116] 4. Surface tension: Test UV inkjet inks using a surface tension meter at room temperature (23±2°C) and relative humidity (50±5%) in accordance with GB / T 6541-2012. Surface tension should be between 22-40 dynes / cm.

[0117] 5. Thermal conductivity: Determine the thermal conductivity of UV coatings using steady-state heat flow techniques according to ASTM D5470. The thermal conductivity should be ≥ 0.23 W / mk.

[0118] 6. Flame retardancy: According to UL94 standard, use vertical burning test device to test the flame retardancy of coating. Flame retardancy should reach V0 grade.

[0119] 7. Sample appearance: Use visual method to check the surface coating of the sample, which should be uniform and free of defects.

[0120] 8. Coating thickness: Use a film thickness meter to test the coating thickness according to GB / T 13452.2-2008. The thickness should be within the tolerance range of 110±20.

[0121] 9. Pencil hardness: According to GB / T 6739-2006, use a pencil hardness tester to test the coating hardness. The hardness should be ≥1H.

[0122] 10. Adhesion: Test the adhesion of the coating to the aluminum surface using the 100-grid method in accordance with GB / T 9286. Adhesion should reach level 0.

[0123] 11. Bending deformation: According to GB / T 6742-86, the bending deformation of the sample is tested using a 20mm curvature radius rod. The coating is qualified if there is no paint peeling, cracks or other defects.

[0124] 12. Shear strength: Test the coating shear strength using a tensile testing machine in accordance with GB / T 7124. The shear strength should be ≥10MPa.

[0125] 13. Tensile strength: Test the coating tensile strength using a tensile testing machine in accordance with GB / T 6329-1996. The tensile strength should be ≥10MPa.

[0126] 14. Impact Resistance: The coating's impact resistance is tested using the drop hammer method in accordance with GB / T 1732-2020. After a 1kg drop hammer is dropped from a height of 50cm, the coating exhibits no paint peeling, cracking, or other defects and meets insulation withstand voltage requirements.

[0127] 15. Abrasion resistance: The coating's wear resistance was tested using an abrasion tester in accordance with GB-T 1689-2014. After 1000 cycles of numbing reciprocating loads of 1 kg, the coating showed no wear and tear and met the insulation withstand voltage requirements.

[0128] 16. Insulation resistance: Test the insulation resistance of the coating using an insulation resistance meter in accordance with GB-T 10064-2006. Apply a DC voltage of 1kV for 5s. The insulation resistance should be ≥1GΩ.

[0129] 17. Breakdown Voltage: The coating breakdown voltage is tested using a coil withstand voltage tester in accordance with GB-T 1408.1-2016. The coating should not break down at DC4kV or AC2.23kV, meeting the insulation withstand voltage requirements.

[0130] 18. Electrolyte resistance: After being sealed and immersed in electrolyte for 10 days at room temperature, the coating showed no blistering or cracking, and the bonding strength requirements with the structural adhesive were met. The 100-grid test passed level 0, meeting the insulation withstand voltage requirements.

[0131] 19. Acid resistance: According to GB / T 9274-1988, the coating is immersed in 5% HCl for 2 hours. After the test, the coating has no blistering or cracking, and the bonding strength requirements with the structural adhesive are met. The 100-grid test passes level 0, meeting the insulation withstand voltage requirements.

[0132] 20. Alkali resistance: According to GB / T 9274-1988, the coating is immersed in 5% NaOH for 2 hours. After the test, the coating has no blistering or cracking, and the bonding strength requirements with the structural adhesive are met. The 100-grid test passes level 0, meeting the insulation withstand voltage requirements.

[0133] 21. Water resistance: According to GB / T 1733-1993, the coating was immersed in deionized water at room temperature for 168 hours. After the test, the coating showed no blistering or cracking, and the bonding strength with the structural adhesive met the requirements. The 100-grid test passed level 0, meeting the insulation withstand voltage requirements.

[0134] 22. Salt spray resistance: The coating's salt spray resistance was tested using a salt spray tester in accordance with ASTM B117. After testing, the coating showed no blistering or cracking, and the bonding strength with the structural adhesive met the requirements. The 100-grid test passed level 0, meeting the insulation withstand voltage requirements.

[0135] 23. High Temperature and Humidity Resistance: The test temperature was set at 85°C and the humidity was 85%. The coated samples were stored for 7 days. After testing, the coating showed no blistering or cracking, and the bonding strength with the structural adhesive met the requirements. The 100-grid test passed Level 0, meeting the insulation withstand voltage requirements.

[0136] Thermal shock resistance: The coating was tested under a -25°C and 40°C temperature cycle for four consecutive cycles. After the test, the coating showed no blistering or cracking, and the bonding strength with the structural adhesive met the requirements. The 100-grid test passed level 0, meeting the insulation withstand voltage requirements.

[0137] Table 1: Summary of inkjet and coating performance tests

[0138]

[0139]

[0140] Table 2: Storage stability test data of the examples at 60°C

[0141]

[0142] According to the data in Table 1, Examples 1-3 provided in this patent meet the requirements of high-precision printing in terms of viscosity (≤30cps) and particle size (D97≤300nm). In addition, Table 2 shows that at a printing temperature of 60°C, Examples 1-3 can be stably stored for more than 60 days, significantly reducing the risk of nozzle clogging, thereby avoiding economic losses in the production process. At the same time, Examples 1-3 meet the strict requirements of 800V new energy vehicle batteries for insulating coatings in terms of electrical performance, weather resistance and stability. Therefore, the spraying scheme proposed in this patent can effectively replace the existing blue film technology and provide reliable insulation technology support for further improvement of battery voltage.

[0143] Comparison of Example 1 and Comparative Example 1 shows that the addition of a low-molecular-weight hyperbranched acrylate polyurethane effectively improves the mechanical properties and chemical resistance of the coating. This effect is primarily attributed to the dense acrylate functional groups and the dense network structure formed during the curing process, but this also comes at the expense of some adhesion and flexural properties.

[0144] By comparing Example 1 with Comparative Example 2, it can be seen that the addition of anhydride-modified epoxy acrylate can significantly enhance the electrolyte resistance of the material, which may be due to the reaction between the epoxy group and the anhydride to form a stable three-dimensional network structure.

[0145] Comparison of Example 1 and Comparative Example 3 shows that the use of an acrylated polyurethane with a polyether polyol backbone improves the material's adhesion, flexural deformation, and shear strength. This is likely due to the presence of a large number of polar groups on its surface, which allows for better bonding with the aluminum surface. However, excessive addition of this resin can increase viscosity and decrease chemical resistance.

[0146] The comparison results of Example 1 and Comparative Example 4 show that the addition of a low molecular weight diol chain-extended acrylate polyurethane oligomer can reduce the viscosity of the system while maintaining good adhesion and hardness.

[0147] Comparison of Example 1 and Comparative Example 5 shows that the addition of an adhesion promoter helps improve the adhesion of the coating. It is worth noting that since no defoaming agent was added in Comparative Example 5, resulting in pores on the coating surface, only mechanical properties testing was performed. Because these pores could lead to high-voltage breakdown, electrical performance testing was not performed.

[0148] Comparison between Example 1 and Comparative Example 6 shows that the color paste without the addition of the self-made resin causes the toner particles to agglomerate, with a particle size of 498 nm, which is larger than the nozzle diameter and cannot be sprayed for sample preparation.

[0149] In summary, the present invention provides a method for preparing a micronized and stable UV insulating inkjet for a new energy vehicle battery cell and its application, providing a low-viscosity, micronized and long-lasting stable UV insulating inkjet that can be stably present for a long time at an ink cartridge temperature of 60°C, avoiding the risk of nozzle clogging due to increased viscosity or increased particle size. The formula contains a variety of low molecular weight hyperbranched modified acrylic resins, monofunctional, difunctional, trifunctional, tetrafunctional and hexafunctional acrylate monomers, high-efficiency UV additives and self-made color pastes. By precisely blending the above raw materials, supplemented by scientific formula design and process control, a UV inkjet that is resistant to boiling, acid and alkali, electrolyte, impact, salt spray, high adhesion, high shear strength, high insulation and fast curing is finally obtained.

[0150] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0151] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing micronized stable UV insulating inkjet, characterized in that: The method comprises the following steps: S1. Evenly mix acrylate monomer, UV additive, and modified acrylate resin to obtain varnish; S2. Add the homemade color paste to the varnish obtained in S1 and stir until the mixture is uniform to obtain a pre-UV insulating inkjet ink; S3. Filter the pre-UV insulating inkjet through a filter paper with a pore size of 0.3 µm to test whether the inkjet particle size is ≤300 nm. If not, re-filter until the particle size meets the requirements, thus obtaining a low-viscosity, micronized, and long-lasting stable UV insulating inkjet. The components of the UV insulating inkjet are composed of the following by weight: 20-40 parts of low molecular weight hyperbranched modified acrylic resin, 50-70 parts of acrylate monomer, 2-10 parts of UV additive, and 1-7 parts of self-made color paste; The low molecular weight hyperbranched modified acrylic resin includes low molecular weight hyperbranched acrylate polyurethane, anhydride modified epoxy acrylate, acrylate polyurethane with polyether polyol as the main chain and acrylate polyurethane oligomer with low molecular weight polyol chain extension; The preparation method of the homemade color paste is as follows: color powder, inorganic filler, grinding resin, acrylate monomer, and wetting dispersant are mixed and stirred evenly, transferred to a color paste grinder, ground with 0.2 mm zirconium oxide beads to a particle size of ≤300 nm, and filtered to obtain the homemade color paste.

2. The method for preparing a micronized and stable UV insulating inkjet according to claim 1, characterized in that: The low molecular weight hyperbranched acrylate polyurethane is prepared according to the following method: diisocyanate, under the action of catalyst I, undergoes hydroxyl addition and end-capping with a core molecule and a hydroxyl-containing acrylate monomer.

3. The method for preparing a micronized and stable UV insulating inkjet according to claim 2, characterized in that: The core molecule is selected from at least one of pentaerythritol and dipentaerythritol.

4. The method for preparing micronized and stable UV insulating inkjet according to claim 1, characterized in that: The acrylic acid ester monomer is obtained by addition polymerization of glycidyl methacrylate and acid anhydride under the action of catalyst II.

5. The method for preparing micronized and stable UV insulating inkjet according to claim 4, characterized in that: The acid anhydride is selected from at least one of phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride and tetrahydrophthalic anhydride.

6. The method for preparing micronized and stable UV insulating inkjet according to claim 1, characterized in that: The acrylic polyurethane with the polyether polyol as the main chain is obtained by adding hydroxyl groups to the polyether polyol and the acrylate monomer containing hydroxyl groups in the presence of a catalyst I to form an end cap.

7. The method for preparing micronized and stable UV insulating inkjet according to claim 6, characterized in that: The low molecular weight polyol chain-extended acrylate polyurethane oligomer is obtained by capping the diisocyanate with a low molecular weight polyol and a hydroxyl-containing acrylate monomer in the presence of a catalyst I by hydroxyl addition.

8. An application of a UV insulating inkjet ink prepared by the method for preparing a micronized and stable UV insulating inkjet ink according to any one of claims 1 to 7, characterized in that: The UV insulating inkjet is applied to the insulating protection of the outer packaging of the power battery cell of new energy vehicles.

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