Recoating full-solid-content UV insulating protective paint and preparation method thereof

Abstract

The invention discloses a recoatable full-solid-content UV insulating protective paint and a preparation method thereof, and belongs to the technical field of paints. The recoatable all-solid-content UV-curable insulating protective paint is prepared from the following raw materials in percentage by mass: 20 to 45 percent of urethane acrylate, 5 to 10 percent of acrylic resin, 2 to 8 percent of trifunctional acrylate monomer, 26 to 35 percent of monofunctional acrylate monomer, 3 to 6 percent of initiator, 7 to 13 percent of filler, 1 to 3 percent of color paste and 2 to 4 percent of adhesion promoter. 0.5%-1% of a thixotropic auxiliary agent and 0.3%-0.6% of a leveling agent. By limiting the raw material components and the proportion of the protective paint, the prepared recoatable full-solid-content UV insulation protective paint has good insulation performance, is high in thixotropy and good in paint hanging performance, can be recoated, can effectively solve the problems of poor curing of a dark-color thick coating and paint hanging at edges and corners, can provide strong protection for the aluminum shell of a power battery, and has good application prospects. Meanwhile, the curing speed is high, the process is simple, energy conservation and environmental protection can be achieved, and the wide market application prospect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a recoatable full-solid UV insulating protective varnish and a preparation method thereof. Background Art

[0002] New energy vehicles are developing at a breakneck pace and gradually capturing the market. Power batteries, as core components and the source of power for new energy vehicles, are facing increasing demands for production capacity and quality. Coating with blue film is a crucial step in the production of power batteries. Blue film, also known as isolation film, anti-adhesion film, or protective film, is classified as either single-sided or double-sided release film. The blue film used in power batteries is typically an insulating material that separates battery cells, shielding them from the effects of various faults in a single cell on other cells and preventing a "one-failure-all-failure" scenario. The blue film provides insulation and protection for the battery cells, and is resistant to corrosion, high temperatures, high voltages, and exhibits excellent tensile strength.

[0003] However, the blue film itself has no adhesion to the aluminum shell of the battery cell, and it needs the help of a specific structural glue to be attached to the surface of the aluminum shell. During the bonding process, since the blue film is relatively thin and soft, it is easy to cause defects such as wrinkles, bubbles, and scratches. Moreover, the blue film is not wear-resistant. After long-term use, it is easy to cause wear on the edges and corners, and the insulation performance is greatly reduced, which cannot meet the requirements. Compared with the existing blue film, the new insulating protective paint is harder and more wear-resistant while taking into account flexibility. After long-term use, the new insulating protective paint still has good protection for the material, its adhesion will not change significantly, and the tensile strength can still reach more than 10MPa. It is difficult for water vapor to pass through the paint film and contact the material, and will not cause the insulation voltage resistance effect to fail. In terms of process, the new insulating protective paint is also relatively simple, and adopts a spray recycling method with high production efficiency and less waste. For the protection of power batteries, the new UV insulating protective paint is a reliable solution with excellent performance and simple process.

[0004] Commercially available UV insulating coatings for battery casings can be applied via inkjet or spray coating. Inkjet coating is currently the most popular process, offering high coating utilization, but production efficiency is far lower than spray coating, especially for non-planar workpieces. Spray coating offers high coating efficiency, and with the support of recycling equipment, it can also ensure coating utilization rates exceeding 90%. However, this process places high demands on the coating's application properties. High viscosity prevents spraying, while low viscosity can lead to film runoff and sagging. Furthermore, the coating also demands high workpiece shape. This is particularly true for rectangular power battery casings, which contain right-angled edges. Spray coating can easily cause the paint to not adhere to the coating or be too thin, resulting in electrical leakage. For darker UV coatings, applying too thick a film can easily lead to incomplete curing, compromising coating performance. Therefore, there is an urgent need for new UV insulating coatings that are better suited for spray coating, can be reapplied repeatedly, and offer superior coating results, particularly those with universally adaptable shapes. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention provides a recoatable, all-solid UV insulating protective varnish and a preparation method thereof. By limiting the raw material components and proportions of the protective varnish, the present invention produces a recoatable, all-solid UV insulating protective varnish having excellent insulating properties, strong thixotropy, and good paint-holding properties. This varnish can be recoated, effectively resolving the issues of poor curing of thick, darkened colors and paint-holding on sharp edges. It can provide strong protection for aluminum housings of power batteries, while also offering fast curing, a simple process, and energy conservation and environmental protection, thus possessing broad market application prospects.

[0006] The technical solutions of the present invention are as follows:

[0007] The first aspect of the present invention provides a recoatable all-solid UV-curing insulating protective paint, which includes the following raw materials, by mass percentage: 20%-45% polyurethane acrylate, 5%-10% acrylic resin, 2%-8% trifunctional acrylate monomer, 26%-35% monofunctional acrylate monomer, 3%-6% initiator, 7%-13% filler, 1%-3% color paste, 2%-4% adhesion promoter, 0.5%-1% thixotropic additive, and 0.3%-0.6% leveling agent.

[0008] Preferably, the polyurethane acrylate is fatty acid modified polyurethane;

[0009] Preferably, the viscosity of the polyurethane acrylate is lower than 4000 mPa·s, and / or the polyurethane acrylate includes at least one of Yulankolu L8400A and Changxing Chemical ETERCURE 61660.

[0010] Preferably, the acrylic resin is a solid acrylate resin;

[0011] Preferably, the molecular weight of the solid acrylate resin is 20,000-60,000, and / or,

[0012] The tg value of the solid acrylic ester resin is 50-70° C., and / or the solid acrylic ester resin includes at least one of Rohm Chemical LP65 / 11 and LP65 / 12.

[0013] Preferably, the trifunctional acrylate monomer includes at least one of pentaerythritol triacrylate and trimethylolpropane triacrylate.

[0014] Preferably, the monofunctional acrylate monomer includes at least one of isobornyl acrylate, isobornyl methacrylate, cyclotrimethylolpropane formal acrylate, and phenoxyethyl acrylate.

[0015] Preferably, the initiator includes at least one of 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl acetone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;

[0016] The filler is a powder filler;

[0017] Preferably, the filler comprises at least one of modified boron nitride and fumed silica;

[0018] Preferably, the color paste is a UV monomer color paste;

[0019] Preferably, the color paste includes one or more of UV15:4 blue-20, UV254 red-35, UV154 yellow-40, and UV white-50.

[0020] Preferably, the adhesion promoter includes at least one of a UV-curable phosphate ester and a siloxane coupling agent;

[0021] The leveling agent is a polyether-modified silicone leveling agent with good recoatability.

[0022] Preferably, the leveling agent is Digo 2100.

[0023] Preferably, the thixotropic agent is polyamide wax powder;

[0024] Preferably, the polyamide wax powder includes at least one of Hemmings THIXATROL PM8056 and Arkema CRAYVALLAC MT.

[0025] The second aspect of the present invention provides a method for preparing the recoatable full-solid UV insulating protective paint described in the first aspect, the preparation method comprising the following steps:

[0026] S1: mixing a trifunctional acrylate monomer and a monofunctional acrylate monomer to obtain a monomer mixture;

[0027] S2: adding acrylic resin and initiator to the monomer mixture, heating and mixing, to obtain glue solution I;

[0028] S3: Add filler to glue solution I, disperse evenly, add thixotropic agent, disperse evenly again, add polyurethane acrylate, heat and mix to obtain glue solution II;

[0029] S4: Add adhesion promoter and leveling agent to glue solution II in sequence, stir evenly, and obtain mixed glue solution III;

[0030] S5: Add color paste to glue solution III, stir evenly, filter through 150 mesh filter cloth to obtain recoatable full-solid UV curing insulation protective paint;

[0031] In step S2, the mixing temperature is 55-65°C;

[0032] In step S3, the dispersing speed is 1000-1200 rpm, and the time is 60 min; the heating and mixing temperature is 55-60°C.

[0033] The beneficial technical effects of the present invention are:

[0034] The recoatable all-solid UV-curing insulating protective paint provided by the present invention has extremely strong thixotropy by adding a certain amount of polyamide wax powder, which can effectively solve the problem of paint sticking on the vertical edges and corners of the workpiece without affecting the construction of the paint; through the selection and optimized ratio of resin, monomer and leveling agent, the paint film has recoatability and can be sprayed multiple times, which can effectively solve the problem of UV paint deepening color in one spraying, excessive film thickness and poor curing, and can also prevent the risk of leakage caused by particulate impurities in the paint film, uneven or too thin a coating film, etc.

[0035] The coating prepared with the recoatable, all-solids UV-curable insulating protective lacquer of the present invention exhibits excellent overall performance, with significant improvements in water resistance, aging resistance, and shear strength. It can withstand immersion in water at 85°C for over 300 hours and high-temperature, high-humidity aging for over 2,000 hours, further enhancing the coating's durability. This coating provides strong protection for aluminum power battery casings. Furthermore, the lacquer contains low levels of organic volatiles, resulting in minimal air pollution, a fast curing speed, and a simple process. It also offers energy-saving and environmentally friendly benefits, promising broad market applications. DETAILED DESCRIPTION

[0036] The present invention will be described in detail below with reference to the embodiments.

[0037] Based on the problems of existing coatings, the first aspect of the present invention provides a recoatable all-solid UV-curing insulating protective paint, which includes the following raw materials, by mass percentage: 20%-45% polyurethane acrylate, 5%-10% acrylic resin, 2%-8% trifunctional acrylate monomer, 26%-35% monofunctional acrylate monomer, 3%-6% initiator, 7%-13% filler, 1%-3% color paste, 2%-4% adhesion promoter, 0.5%-1% thixotropic additive, and 0.3%-0.6% leveling agent.

[0038] The UV insulating protective paint prepared by the present invention has strong thixotropy, good paint hanging property, excellent insulation, water resistance, temperature resistance and other properties, and can be re-coated, which can effectively solve the problems of poor curing of thick coating with darker color and paint hanging on sharp edges.

[0039] In some embodiments, the recoatable all-solid UV curing insulating protective paint includes the following raw materials by mass percentage: polyurethane acrylate 20%-40%, acrylic resin 5%-8%, trifunctional acrylate monomer 5%-8%, monofunctional acrylate monomer 26%-35%, initiator 3%-6%, filler 10%-16%, color paste 1%-3%, adhesion promoter 2%-3%, thixotropic additive 0.5%-1%, and leveling agent 0.3%-0.6%.

[0040] In some embodiments, the polyurethane acrylate is fatty acid-modified polyurethane, which has good flexibility and low shrinkage stress, and is conducive to adhesion to metal aluminum.

[0041] In some embodiments, the polyurethane acrylate has a viscosity of less than 4000 mPa.s and good flexibility, which can further improve the adhesion to metal aluminum.

[0042] In some embodiments, the polyurethane acrylate includes at least one of Yulanco L8400A and Changxing Chemical ETERCURE 61660.

[0043] It is understandable that polyurethane acrylate contains amino acrylate bonds and double bonds, and has excellent water resistance, wear resistance and chemical resistance after curing. Designing some special structures on the polyurethane chain segments, such as phosphate groups, epoxy groups, etc., can provide the coating with adhesion to metal.

[0044] In some embodiments, the acrylic resin is a solid acrylate resin.

[0045] In some embodiments, the solid acrylate resin has a molecular weight of 20,000-60,000, has good adhesion to metal, high flexibility, can effectively reduce the shrinkage stress of the system, and can provide a certain degree of recoatability.

[0046] In some embodiments, the solid acrylic resin has a Tg of 50-70° C. It has a moderate molecular weight and good compatibility with other components, which can improve adhesion to metals. It also has high flexibility and can effectively reduce the shrinkage stress of the system.

[0047] In some embodiments, the solid acrylate resin includes at least one of Rohm Chemical LP65 / 11 and LP65 / 12.

[0048] In some embodiments, the trifunctional acrylate monomer includes at least one of pentaerythritol triacrylate and trimethylolpropane triacrylate.

[0049] It is understandable that the trifunctional acrylate monomer can adjust the viscosity of the system and effectively increase the reaction speed of the system, so that the paint film has a certain hardness after curing.

[0050] In some embodiments, the monofunctional acrylate monomer includes at least one of isobornyl acrylate, isobornyl methacrylate, cyclotrimethylolpropane formal acrylate, and phenoxyethyl acrylate.

[0051] It is understandable that the monofunctional acrylate monomer can adjust the viscosity of the system, reduce the shrinkage stress of the system, adjust the recoatability of the paint film after curing, and have excellent adhesion to metal aluminum.

[0052] In some embodiments, the initiator includes at least one of 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl acetone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0053] In some embodiments, the initiator is a mixture of 1-hydroxy-cyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl diphenyl phosphine oxide. Preferably, the mass ratio of the 1-hydroxy-cyclohexyl phenyl ketone to the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide is 1:1.

[0054] The filler is a powder filler.

[0055] In some embodiments, the filler includes at least one of modified boron nitride and fumed silica.

[0056] It is understood that the silicon dioxide and boron nitride have excellent insulation and corrosion resistance, and the modified boron nitride powder has better compatibility with UV curing resin and monomer.

[0057] In some embodiments, the modified boron nitride is H-BN-A from Tianyuan Aerospace Materials.

[0058] In some embodiments, the color paste is a UV monomer color paste.

[0059] In some embodiments, the color paste includes one or more of UV15:4 blue-20, UV254 red-35, UV154 yellow-40, and UV white-50.

[0060] In some embodiments, the adhesion promoter includes at least one of a UV-curable phosphate ester and a siloxane coupling agent.

[0061] In some embodiments, the adhesion promoter is selected from at least one of Changxing EM39, Dow Corning Z-6040, and Momentive A-187.

[0062] In some embodiments, the leveling agent is a polyether-modified silicone leveling agent.

[0063] It can be understood that the leveling agent of the present invention has good recoatability, and Digo 2100 is preferred.

[0064] In some embodiments, the thixotropic agent is polyamide wax powder.

[0065] In some embodiments, the polyamide wax powder includes at least one of Hemmings THIXATROL PM8056 and Arkema CRAYVALLAC MT.

[0066] It is understood that the polyamide wax powder, as a thixotropic agent, can effectively ensure the paint sticking properties of the uncured paint film, making it less likely to sag. However, if it is added in too much amount, the paint viscosity will be affected, making it difficult to apply, while if it is added in too little, it will have no effect.

[0067] The second aspect of the present invention provides a method for preparing the recoatable full-solid UV insulating protective paint described in the first aspect, the preparation method comprising the following steps:

[0068] S1: mixing a trifunctional acrylate monomer and a monofunctional acrylate monomer to obtain a monomer mixture;

[0069] S2: adding acrylic resin and initiator to the monomer mixture, heating and mixing, to obtain glue solution I;

[0070] S3: Add filler to glue solution I, disperse evenly, add thixotropic agent, disperse evenly again, add polyurethane acrylate, heat and mix to obtain glue solution II;

[0071] S4: Add adhesion promoter and leveling agent to glue solution II in sequence, stir evenly, and obtain mixed glue solution III;

[0072] S5: Add color paste to glue solution III, stir evenly, and filter to obtain a recoatable full-solid UV-curing insulation protective paint.

[0073] In some embodiments, in step S2, the mixing temperature is 55-65°C, including but not limited to 55°C, 60°C, and 65°C.

[0074] In some embodiments, in step S3, the dispersion speed is 1000-1200 rpm, including but not limited to 1000 rpm, 1100 rpm, and 1200 rpm; the time is 60 min; and the heating and mixing temperature is 55-65°C, including but not limited to 55°C, 60°C, and 65°C.

[0075] The present invention will be further described below by way of examples.

[0076] It should be noted that the color paste used in the following examples and comparative examples is UV15:4 Blue-20. However, the color paste used in the present invention can be replaced with other color pastes as needed to prepare protective paints of different colors.

[0077] Example 1

[0078] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0079]

[0080]

[0081] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0082] S1: 8% pentaerythritol triacrylate, 16% isobornyl acrylate, and 16% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0083] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0084] S3: Add 8% modified boron nitride H-BN-A to glue solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 37.5% polyurethane acrylate (Lankelu L8400A), heat to 60°C, and mix evenly to obtain glue solution II;

[0085] S4: 2% adhesion promoter EM39 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0086] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0087] Example 2

[0088] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0089]

[0090]

[0091] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0092] S1: 8% pentaerythritol triacrylate, 8% isobornyl acrylate, and 24% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0093] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0094] S3: Add 8% modified boron nitride H-BN-A to glue solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 37.5% Lancolu L8400A, heat to 60°C, and mix evenly to obtain glue solution II;

[0095] S4: 2% adhesion promoter EM39 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0096] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0097] Example 3

[0098] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0099]

[0100]

[0101] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0102] S1: 5% pentaerythritol triacrylate, 16% isobornyl acrylate, and 16% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0103] S2: 8% solid acrylic resin Rohm Chemical LP65 / 11, 2% initiator 184, and 2% initiator TPO were added to the monomer mixture, heated to 60° C. and mixed evenly to obtain glue solution I;

[0104] S3: Add 8% modified boron nitride H-BN-A to adhesive solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 32.5% Changxing Chemical ETERCURE 61660, heat to 60°C, and mix evenly to obtain adhesive solution II;

[0105] S4: 2% adhesion promoter Z-6040 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0106] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0107] Example 4

[0108] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0109]

[0110]

[0111] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0112] S1: 5% pentaerythritol triacrylate, 16% isobornyl acrylate, and 16% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0113] S2: 5% solid acrylic resin Rohm Chemical LP65 / 11, 2% initiator 184, and 2% initiator TPO were added to the monomer mixture, heated to 60° C. and mixed evenly to obtain glue solution I;

[0114] S3: Add 13% modified boron nitride H-BN-A to adhesive solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 21.5% Lancolu L8400A and 14% Changxing Chemical ETERCURE 61660, heat to 60°C, and mix evenly to obtain adhesive solution II;

[0115] S4: 2% adhesion promoter Z-6040 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0116] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0117] Example 5

[0118] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0119]

[0120]

[0121] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0122] S1: 6% pentaerythritol triacrylate, 16% isobornyl acrylate, and 16% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0123] S2: 5% solid acrylic resin Rohm Chemical LP65 / 11, 2% initiator 184, and 2% initiator TPO were added to the monomer mixture, heated to 60° C. and mixed evenly to obtain glue solution I;

[0124] S3: Add 13% modified boron nitride H-BN-A to adhesive solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 16.5% Lancolu L8400A and 18% Changxing Chemical ETERCURE 61660, heat to 60°C, and mix evenly to obtain adhesive solution II;

[0125] S4: 2% adhesion promoter Z-6040 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0126] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0127] Example 6

[0128] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0129]

[0130]

[0131] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0132] S1: 4% pentaerythritol triacrylate, 4% trimethylolpropane triacrylate and 32% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0133] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0134] S3: Add 8% modified boron nitride H-BN-A to glue solution I, disperse evenly, add 1% polyamide wax powder CRAYVALLAC MT, disperse evenly again, add 37.5% polyurethane acrylate (Lankelu L8400A), heat to 60°C, and mix evenly to obtain glue solution II;

[0135] S4: 2% adhesion promoter EM39 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0136] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0137] Comparative Example 1

[0138] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0139]

[0140] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0141] S1: 8% pentaerythritol triacrylate, 4% isobornyl acrylate, and 8% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0142] S2: Add 5% solid acrylic resin (Rohm Chemical LP65 / 11), 2% initiator 184 and 2% initiator TPO to the monomer mixture, heat to 60°C and mix well.

[0143] Obtain glue solution I;

[0144] S3: Add 8% modified boron nitride H-BN-A to glue solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 57.5% polyurethane acrylate (Lankelu L8400A), heat to 60°C, and mix evenly to obtain glue solution II;

[0145] S4: 2% adhesion promoter EM39 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0146] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0147] Comparative Example 2

[0148] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0149]

[0150] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0151] S1: 28% pentaerythritol triacrylate, 8% isobornyl acrylate, and 24% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0152] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0153] S3: Add 8% modified boron nitride H-BN-A to glue solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 17.5% polyurethane acrylate (Lankelu L8400A), heat to 60°C, and mix evenly to obtain glue solution II;

[0154] S4: 2% adhesion promoter EM39 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0155] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0156] Comparative Example 3

[0157] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0158]

[0159] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0160] S1: 5% pentaerythritol triacrylate, 16% isobornyl acrylate, and 16% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0161] S2: Add 2% initiator 184 and 2% initiator TPO to the monomer mixture, heat to 60°C and mix well to obtain glue solution I;

[0162] S3: Add 8% modified boron nitride H-BN-A to adhesive solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 40.5% polyurethane acrylate (ETERCURE 61660), heat to 60°C, and mix evenly to obtain adhesive solution II;

[0163] S4: 2% adhesion promoter Z-6040 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0164] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0165] Comparative Example 4

[0166] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0167]

[0168] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0169] S1: 5% pentaerythritol triacrylate, 16% isobornyl acrylate, and 16% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0170] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0171] S3: Add 13% modified boron nitride H-BN-A to adhesive solution I and disperse evenly. Then add 1% fumed silica and disperse evenly. Then add 21.5% polyurethane acrylate (Lancolu L8400A) and 14% polyurethane acrylate (ETERCURE 61660). Heat to 60°C and mix evenly to obtain adhesive solution II.

[0172] S4: 2% adhesion promoter Z-6040 and 0.5% leveling agent TEGO 2100 were added to the adhesive solution II in sequence, and stirred evenly to obtain a mixed adhesive solution III.

[0173] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0174] Comparative Example 5

[0175] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0176]

[0177] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0178] S1: 6% pentaerythritol triacrylate, 16% isobornyl acrylate, and 18% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0179] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0180] S3: Add 13% modified boron nitride H-BN-A to adhesive solution I, disperse evenly, add 1% polyamide wax powder PM8056, disperse evenly again, add 16.5% polyurethane acrylate (Lancolu L8400A) and 18% polyurethane acrylate (ETERCURE 61660), heat to 60°C, and mix evenly to obtain adhesive solution II;

[0181] S4: Add 0.5% leveling agent TEGO 2100 to the adhesive solution II and stir evenly to obtain a mixed adhesive solution III.

[0182] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0183] Comparative Example 6

[0184] Recoatable full solid UV insulation protective paint, by mass percentage, including the following components:

[0185]

[0186] The method for preparing a recoatable full-solid UV insulating protective paint using the above raw materials comprises: according to the mass percentage of the above raw materials,

[0187] S1: 4% pentaerythritol triacrylate, 4% trimethylolpropane triacrylate and 32% phenoxyethyl acrylate are mixed to obtain a monomer mixture;

[0188] S2: Add 5% solid acrylic resin LP6511, 2% initiator 184, and 2% initiator TPO to the monomer mixture, heat to 60° C. and mix well to obtain glue solution I;

[0189] S3: Add 8% modified boron nitride H-BN-A to glue solution I, disperse evenly, add 1% polyamide wax powder CRAYVALLAC MT, disperse evenly again, add 37.5% polyurethane acrylate (Lankelu L8400A), heat to 60°C, and mix evenly to obtain glue solution II;

[0190] S4: Add 2% adhesion promoter EM39 to the adhesive solution II and stir evenly to obtain mixed adhesive solution III.

[0191] S5: Add 2% color paste to the glue solution III, stir evenly, and filter through a 150-mesh filter cloth to obtain a recoatable full-solid UV-curing insulation protective paint.

[0192] Test example:

[0193] The performance tests of the UV insulating protective paints of the above embodiments and comparative examples are as follows:

[0194] Preparation of test sample: The protective paint prepared in the embodiment or comparative example was evenly coated on a 2 mm thick 2.5 cm × 10 cm laser-treated aluminum plate with a coating thickness of 90-120 μm and UV curing energy of 2000-3000 mj / cm -2 , and then test the performance of the coating.

[0195] Adhesion test: Use a grid knife to cut a 1mm wide 10×10 grid, pull it three times with 3M tape, and observe the adhesion.

[0196] Flexibility: Bend the sample 90° on a 32mm radius of curvature rod to observe whether the paint film falls off or has cracks, and test the adhesion.

[0197] Impact resistance: Use a 1kg drop hammer from a height of 50cm to the surface of the sample, and observe under a 4x magnifying glass to see if there are cracks or paint peeling on the paint film. If the insulation withstand voltage passes, it is OK.

[0198] Hardness: Use a Mitsubishi pencil and a force of 500g to perform a scratch test, and record the hardness without scratches.

[0199] Insulation resistance: Test the insulation resistance of the paint film at DC 1000V DC, 60S.

[0200] Withstand voltage: Test DC2700V, 60S, repeated 25 times, leakage current ≤ 0.1mA, the insulation withstand voltage passes.

[0201] Wear resistance: Tested according to ISO 1518, load 1kg, friction medium CS-17, 45 cycles / minute, 1000 cycles, observe whether the coating is worn through, and test whether the insulation withstand voltage passes.

[0202] High temperature resistance: Place the paint film at 150℃, DC1000V, 60S, and measure the insulation resistance ≥500MΩ to see if it passes; and test the adhesion, appearance and insulation withstand voltage of the coating at 100℃×1000h.

[0203] High and low temperature impact: The paint film is placed in low temperature -40℃ and high temperature 85℃ alternately for 30 minutes, with temperature conversion time of 5 minutes, for 1000 cycles to test the coating adhesion, appearance and insulation withstand voltage.

[0204] Water resistance: Soak the paint film in water at 85℃ for 300h, and test the coating adhesion, appearance, and insulation withstand voltage.

[0205] High temperature and high humidity: Place the paint film at 85℃ and 85% humidity for 2000h, and test the coating's adhesion, appearance, and insulation withstand voltage.

[0206] Acid and alkali resistance: 5% HCl or 5% NaOH, soak the paint film at room temperature for 24 hours, observe the paint film surface, the paint film adhesion is level 0 and the insulation withstand voltage passes, it is OK.

[0207] Recoatability: Apply another layer of paint on the completely cured paint film, UV cure again, and test the adhesion after recoating twice. Adhesion level 0 is OK.

[0208] Paint sticking property: Spray the protective paint of the embodiment or comparative example onto an aluminum shell with sharp edges for a power battery that is 20 cm high, 16 cm long, and 8 cm wide. Inspect the paint film condition with the naked eye and cure the paint film at the same time. Perform a leakage test on the sharp edges of the cured paint film. If the paint film does not ooze oil or sag and does not leak electricity, it is OK.

[0209] Shear strength: tested according to GBT 7124 / ISO 4587, test temperature 25℃, tensile speed 5mm / min, adhesive layer thickness 0.2mm.

[0210] Shear strength after aging: The paint film was aged at 85℃, 85% humidity for 2000h. Then the aged shear strength of the paint film was tested according to GBT7124 / ISO 4587, with a test temperature of 25℃, a tensile speed of 5mm / min, and a thickness of 0.2mm.

[0211] The test results are shown in Table 1-2.

[0212] Table 1: Performance test results of the embodiment

[0213]

[0214]

[0215] Table 2: Comparative performance test results

[0216]

[0217]

[0218]

[0219] As can be seen from the table above, the coatings in the examples all exhibit excellent electrical insulation properties. Their adhesion, flexibility, impact resistance, temperature resistance, hardness, acid and alkali resistance, and wear resistance all exceed the test requirements. They also exhibit excellent water resistance and high-temperature and high-humidity aging performance. After immersion in 85°C water for 300 hours, the coatings' adhesion and appearance remain unchanged from their initial state, and their electrical insulation performance remains unchanged, exceeding the test standards. Furthermore, the coatings exhibit excellent recoatability, with no dripping or oiling on sharp corners after spraying, and no defects such as leakage after curing.

[0220] Compared to Example 1, Comparative Example 1 has a lower proportion of monofunctional monomers, resulting in excessively high coating viscosity, poor workability, poor film flexibility, and paint peeling upon recoating. The monomers used in the examples not only have excellent adhesion to aluminum, but also reduce the shrinkage stress of the coating, increase the flexibility of the coating, and effectively reduce the viscosity of the system. Compared to Example 2, Comparative Example 2 reduces the trifunctional polyurethane acrylic resin, which has good adhesion to aluminum. This increases the proportion of trifunctional monomers in the coating system, resulting in high cure shrinkage, poor coating adhesion, and paint peeling upon recoating. Compared to Example 3, Comparative Example 3 does not contain a solid acrylic resin but increases the content of trifunctional polyurethane acrylic resin. This results in reduced flexibility, high cure shrinkage stress, poor adhesion, and poor paint holding properties, which affects recoatability. Compared to Example 4, Comparative Example 4 does not include a polyamide wax powder thixotropic agent, resulting in insufficient thixotropy and poor paint holding properties on sharp edges. Compared to Example 5, Comparative Example 5 does not include an adhesion promoter, resulting in insufficient adhesion and paint peeling after water aging. Compared with Example 6, Comparative Example 6 changes the type of leveling agent. Comparative Example 6 uses leveling agent BYK333, which has a greater impact on recoatability. Therefore, the resulting coating has no recoatability.

[0221] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.

Claims

1. A recoatable full-solid UV curing insulation protective paint, characterized in that: Calculated by mass percentage, it includes the following raw materials: polyurethane acrylate 20%-45%, acrylic resin 5%-10%, trifunctional acrylate monomer 2%-8%, monofunctional acrylate monomer 26%-35%, initiator 3%-6%, filler 7%-13%, color paste 1%-3%, adhesion promoter 2%-4%, thixotropic agent 0.5%-1%, and leveling agent 0.3%-0.6%.

2. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The polyurethane acrylate is fatty acid modified polyurethane; Preferably, the viscosity of the polyurethane acrylate is less than 4000 mPa.s, and / or, The polyurethane acrylate includes at least one of Yulankolu L8400A and Changxing Chemical ETERCURE 61660.

3. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The acrylic resin is a solid acrylic ester resin; Preferably, the molecular weight of the solid acrylate resin is 20,000-60,000, and / or the tg value of the solid acrylate resin is 50-70° C., and / or The solid acrylic resin includes at least one of Rohm Chemical LP65 / 11 and LP65 / 12.

4. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The trifunctional acrylate monomer includes at least one of pentaerythritol triacrylate and trimethylolpropane triacrylate.

5. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The monofunctional acrylate monomer includes at least one of isobornyl acrylate, isobornyl methacrylate, cyclotrimethylolpropane formal acrylate, and phenoxyethyl acrylate.

6. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The initiator includes at least one of 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl acetone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

7. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The filler is a powder filler; Preferably, the filler comprises at least one of modified boron nitride and fumed silica; Preferably, the color paste is a UV monomer color paste; Preferably, the color paste includes one or more of UV15:4 blue-20, UV254 red-35, UV154 yellow-40, and UV white-50.

8. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The adhesion promoter includes at least one of a UV-curable phosphate ester and a siloxane coupling agent; The leveling agent is a polyether-modified silicone leveling agent.

9. The recoatable full-solid UV insulating protective paint according to claim 1, characterized in that: The thixotropic agent is polyamide wax powder; Preferably, the polyamide wax powder includes at least one of Hemmings THIXATROL PM8056 and Arkema CRAYVALLAC MT.

10. A method for preparing the recoatable all-solid UV insulating protective varnish according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: according to mass percentage, S1: mixing a trifunctional acrylate monomer and a monofunctional acrylate monomer to obtain a monomer mixture; S2: adding acrylic resin and initiator to the monomer mixture, heating and mixing, to obtain glue solution I; S3: Add filler to glue solution I, disperse evenly, add thixotropic agent, disperse evenly again, add polyurethane acrylate, heat and mix to obtain glue solution II; S4: Add adhesion promoter and leveling agent to glue solution II in sequence, stir evenly, and obtain mixed glue solution III; S5: Add color paste to glue solution III, stir evenly, and filter to obtain a recoatable full-solid UV-curing insulation protective paint; In step S2, the mixing temperature is 55-65°C; In step S3, the dispersing speed is 1000-1200 rpm, and the time is 60 min; the heating and mixing temperature is 55-65°C.

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