Low-temperature curing high-performance electrophoretic paint and preparation method thereof

Abstract

This application relates to the field of electrophoretic paint technology, specifically disclosing a low-temperature curing high-efficiency electrophoretic paint and its preparation method. The low-temperature curing high-efficiency electrophoretic paint comprises the following components by weight: 45-55 parts epoxy resin; 35-45 parts acrylic resin; 5-10 parts curing agent; 1-2 parts leveling agent; 1-2 parts anti-settling agent; and 5-10 parts pigment filler. The curing agent is a modified imidazole compound. The preparation method involves: mixing epoxy resin and acrylic resin by stirring; then adding the leveling agent, anti-settling agent, and pigment filler during stirring; and grinding the mixture after further stirring to obtain a resin mixture; finally, mixing the resin mixture and the curing agent to obtain the final product. The low-temperature curing high-efficiency electrophoretic paint of this application can significantly reduce the curing temperature, reduce energy consumption, reduce environmental pollution, and ensure that the electrophoretic paint has good film-forming properties, adhesion, and corrosion resistance during application.

Description

Technical Field

[0001] This application relates to the field of electrophoretic paint technology, and more specifically, to a low-temperature curing high-efficiency electrophoretic paint and its preparation method. Background Technology

[0002] Electrophoretic paint, also known as electrophoretic coating, is a coating material that uses an external electric field to cause pigments and resin particles suspended in an electrophoretic solution to migrate in a directional manner and deposit on the surface of a substrate with one of the electrodes. Due to its environmentally friendly characteristics, it has a wide range of applications in industry, especially in the automotive, building materials, hardware, and home appliance industries.

[0003] Epoxy acrylic electrophoretic paint is a type of solvent-free or low-solvent coating that combines the properties of epoxy and acrylic resins. It exhibits excellent chemical stability, light stability, weather resistance, adhesion, and abrasion resistance, resulting in superior overall performance and a wide range of applications. The main components of epoxy acrylic electrophoretic paint include resin, pigments, fillers, and additives. The resin serves as the matrix material, while acrylic resin provides good adhesion and flexibility, and epoxy resin increases the corrosion resistance of the paint film. Pigments impart color and opacity to the coating; fillers adjust the coating volume, increase film thickness, and hardness; and additives, such as leveling agents, defoamers, and wetting agents, improve the performance of the electrophoretic paint. Epoxy acrylic electrophoretic paint is widely used for surface protection and enhancement of various materials, such as automobiles, furniture, appliances, and construction. Its advantages include a dense coating, high gloss, strong corrosion resistance, and environmental friendliness.

[0004] Regarding the aforementioned technologies, the inventors believe that electrophoretic paint generally needs to be above 160℃ to fully cure during application. This not only consumes a lot of energy but may also lead to an increase in energy consumption and carbon emissions. Furthermore, high-temperature curing can easily cause workpiece deformation, especially in the coating process of thin sheet parts, where thermal deformation is particularly prominent, limiting the widespread application of electrophoretic paint in environmentally friendly production systems. Although some studies have attempted to lower the curing temperature by adding specific catalysts, this often results in electrophoretic paint failing to maintain good film-forming properties, adhesion, and corrosion resistance.

[0005] Therefore, there is an urgent need to propose a solution to address the aforementioned technical problems. Summary of the Invention

[0006] In order to significantly reduce the curing temperature, reduce energy consumption, and reduce environmental pollution while ensuring good film-forming properties, adhesion, and corrosion resistance of the electrophoretic paint, this application provides a low-temperature curing high-efficiency electrophoretic paint and its preparation method.

[0007] In the first aspect, this application provides a low-temperature curing high-efficiency electrophoretic paint, which adopts the following technical solution:

[0008] A low-temperature curing high-efficiency electrophoretic coating comprises the following components in parts by weight:

[0009] 45-55 parts epoxy resin;

[0010] 35-45 parts acrylic resin;

[0011] 5-10 parts of curing agent;

[0012] 1-2 parts leveling agent;

[0013] 1-2 parts anti-settling agent;

[0014] 5-10 parts pigment filler;

[0015] The curing agent is a modified imidazole compound.

[0016] By employing the above technical solutions, epoxy resin in electrophoretic paint enhances adhesion and corrosion resistance, as well as improves the mechanical properties of the coating. The epoxy groups in the epoxy resin molecule can undergo addition reactions with the double bonds in the acrylic acid molecule to form copolymers. These copolymers possess excellent heat resistance and chemical resistance, significantly improving the coating's adhesion, corrosion resistance, and mechanical properties. The polar groups in the acrylic resin molecule can form chemical bonds with various substrate surfaces, thereby enhancing the adhesion between the coating and the substrate. Furthermore, the added acrylic resin can be dispersed in the epoxy resin to compensate for defects caused by curing shrinkage, resulting in a denser coating and exhibiting more stable and superior film quality. Modified imidazole compounds, by introducing other groups or altering their chemical structure, further optimize their curing performance, exhibiting better compatibility with resin molecules in the mixing system of low-temperature curing high-efficiency electrophoretic paint. This also lowers the curing temperature of the low-temperature curing high-efficiency electrophoretic paint while ensuring excellent cross-linking effects, ultimately yielding a coating of superior quality. This application describes a low-temperature curing high-efficiency electrophoretic paint. By mixing epoxy resin and acrylic resin in a specific ratio range and supplementing with a modified imidazole compound as a curing agent, the curing temperature can be significantly reduced, energy consumption can be reduced, environmental pollution can be reduced, and the electrophoretic paint can be ensured to have good film-forming properties, adhesion and corrosion resistance.

[0017] Preferably, the epoxy resin has a molecular weight of 400-800 Daltons.

[0018] By adopting the above technical solutions, low molecular weight epoxy resin has high hardness, high brittleness, and low impact strength; although high molecular weight epoxy resin performs better in terms of heat resistance, strength, and chemical resistance, it can lead to uneven paint film; while epoxy resin with the above molecular weight has better compatibility with other component raw materials after application. When the low-temperature curing high-efficiency electrophoretic paint is cured at a lower temperature, it can exhibit better film-forming properties, and the resulting paint film also has better adhesion and corrosion resistance.

[0019] Preferably, the functional group content of the acrylic resin is 20-30 mg KOH / g.

[0020] By adopting the above technical solutions, a low functional group content in acrylic resin will result in lower film hardness and poor weather resistance, making it susceptible to aging due to environmental factors. A high functional group content in acrylic resin can improve the weather resistance and hardness of the coating, but the curing speed is relatively slow, and it is difficult to ensure the uniformity of the film at relatively low curing temperatures. In contrast, acrylic resin with the above-mentioned functional group content has better compatibility with other component raw materials after application. When low-temperature curing high-efficiency electrophoretic paint is cured at a lower temperature, a higher quality film can be obtained.

[0021] Preferably, the components of the low-temperature curing high-efficiency electrophoretic paint also include 0.2-1 parts by weight of ultraviolet curing additive.

[0022] By adopting the above technical solution and introducing ultraviolet curing additives, the electrophoretic paint can be cured quickly under ultraviolet light, further expanding its application range. It is especially suitable for the fast drying requirements under on-site construction and outdoor operation conditions. At the same time, the low-temperature curing high-efficiency electrophoretic paint obtained by applying ultraviolet curing additives can be cured in just 2 minutes under ultraviolet light source irradiation, which greatly shortens the curing cycle and is suitable for rapid assembly line operation of large equipment.

[0023] Preferably, the leveling agent is a blend of polyether-modified organosilicon and fluorosilicone, wherein the fluorosilicone blend is a mixture of fluorinated siloxane and organosilicon leveling agent.

[0024] By adopting the above technical solutions, polyether-modified organosilicon as a leveling agent can significantly improve the leveling speed of electrophoretic paint and provide good substrate wetting, enabling the electrophoretic paint to spread quickly and evenly during construction. Fluorosilicone blends, which are composed of fluorinated modified siloxanes and organosilicon leveling agents, not only have strong surface activity and foaming suppression properties, but also excellent scratch resistance and chemical stability, thus significantly improving the quality of the paint film. Furthermore, the combined use of polyether-modified organosilicon and fluorosilicone blends as leveling agents demonstrates strong applicability to the application and curing of low-temperature curing high-efficiency electrophoretic paints, thereby achieving better leveling effects.

[0025] Preferably, the anti-settling agent is one or a combination of two of bentonite and fumed silica.

[0026] By adopting the above technical solutions, the role of anti-settling agents in electrophoretic paint is mainly reflected in preventing sedimentation and stratification, so as to make the electrophoretic paint particles uniformly dispersed, thereby improving dispersibility and stability. All of the above-mentioned anti-settling agents are suitable for the mixing system of low-temperature curing high-efficiency electrophoretic paint and can play an excellent and stable corresponding role.

[0027] Preferably, the pigment filler is one or a combination of two of nano-titanium dioxide and nano-zinc oxide.

[0028] By adopting the above technical solution, the pigment filler is the colorant of the electrophoretic paint, which gives the paint film rich colors and gloss. In addition to coloring and enhancing the gloss of the paint film, the pigment filler can also improve the application performance and stability of the coating, thereby making the low-temperature curing high-efficiency electrophoretic paint have better overall application quality.

[0029] Preferably, the low-temperature curing high-efficiency electrophoretic paint further contains 1-2 parts by weight of functional additives, which are composed of organosilicon active particles and secane trioxide, and the weight ratio of organosilicon active particles to secane trioxide is (2-5):1.

[0030] The organosilicon active particles are prepared by the following steps:

[0031] Ethyl orthosilicate and hydroxypropyl methacrylate were mixed in a molar ratio of 1:(3.5-4.5) and reacted under an acid catalyst at 75-80℃ for 2-3 hours. During the reaction, the byproduct ethanol was continuously removed, and finally, organosilicon active particles were obtained.

[0032] By adopting the above technical solutions, bismuth trioxide, with its high melting point and good chemical stability, can improve the corrosion resistance and stability of electrophoretic paint. Furthermore, bismuth trioxide can maintain the structural stability of the paint film even at relatively low curing temperatures. The use of organosilicon active particles introduces Si-O bonds into the electrophoretic paint. Utilizing the cross-linking network properties of Si-O bonds, it not only increases the cross-linking density between polymer molecular chains but also enhances the polymer's reactivity during electrophoresis. Therefore, even at relatively low curing temperatures, the electrophoretic paint can still maintain good film-forming properties, adhesion, and corrosion resistance. Simultaneously, when organosilicon active particles and bismuth trioxide are used as functional additives, they exhibit excellent synergistic effects, significantly improving the film-forming properties, adhesion, and corrosion resistance of the electrophoretic paint at relatively low curing temperatures. This results in a significant improvement in the overall application of low-temperature curing high-performance electrophoretic paints.

[0033] Preferably, the weight ratio of the organosilicon active particles to bismuth trioxide is 3:1.

[0034] By adopting the above technical solution, when the organosilicon active particles and bismuth trioxide in the above weight ratio are used together, the two have a better synergistic effect in the mixing system of low-temperature curing high-efficiency electrophoretic paint, and the overall quality of the low-temperature curing high-efficiency electrophoretic paint is also better.

[0035] Secondly, this application provides a method for preparing a low-temperature curing high-efficiency electrophoretic paint, using the following technical solution:

[0036] A method for preparing a low-temperature curing high-efficiency electrophoretic paint includes the following steps:

[0037] (1) Prepare raw materials containing epoxy resin, acrylic resin, curing agent, leveling agent, anti-settling agent and pigment filler according to the formula;

[0038] (2) Stir and mix the epoxy resin and acrylic resin in step (1), then add leveling agent, anti-settling agent and pigment filler during the stirring process, and then grind after stirring and mixing to obtain resin mixture.

[0039] (3) Stir and mix the resin mixture and curing agent in step (2) to obtain low-temperature curing high-efficiency electrophoretic paint.

[0040] By adopting the above technical solution, the above preparation method is simple to operate, and the orderly addition and mixing of each raw material is conducive to the full cooperation and excellent corresponding effect of each raw material, thereby obtaining a high-quality and stable low-temperature curing high-efficiency electrophoretic paint; at the same time, the entire preparation method is more in line with industrial production, so that the low-temperature curing high-efficiency electrophoretic paint can also meet the needs of large-scale industrial production.

[0041] In summary, this application has the following beneficial effects:

[0042] 1. In the low-temperature curing high-efficiency electrophoretic paint, this application mixes epoxy resin and acrylic resin in a specific ratio range and uses modified imidazole compounds as curing agents, which can significantly reduce the curing temperature, reduce energy consumption, reduce environmental pollution, and ensure good film-forming properties, adhesion and corrosion resistance of the electrophoretic paint.

[0043] 2. This application uses specially prepared organosilicon active particles and secane trioxide as functional additives. Through the excellent synergistic effect of the two, the film-forming properties, adhesion and corrosion resistance of electrophoretic paint can be significantly improved at a relatively low curing temperature, thereby significantly improving the overall application of low-temperature curing high-performance electrophoretic paint. Detailed Implementation

[0044] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0045] Unless otherwise specified, all raw materials used in the preparation examples, embodiments, and comparative examples of this application are commercially available.

[0046] The UV curing agent is TEGO 432 UV curing anti-shrinkage agent;

[0047] The polyether-modified organosilicon was purchased from Qingdao Baisenmao New Material Co., Ltd. as anti-shrinkage polyether-modified organosilicon BSM1270TEGO270.

[0048] The fluorinated modified siloxane was purchased from Merck Chemicals in Germany as a fluorinated modified polysiloxane leveling agent MOK-2027.

[0049] The silicone leveling agent was purchased from BYK-333 silicone leveling agent.

[0050] Preparation examples of raw materials and / or intermediates

[0051] Preparation Example 1

[0052] An organosilicon active particle is prepared by the following steps:

[0053] Ethyl orthosilicate and hydroxypropyl methacrylate were mixed in a molar ratio of 1:4 and reacted under an acid catalyst at 77.5°C for 2.5 h. During the reaction, the byproduct ethanol was continuously removed, and finally, organosilicon active particles were obtained.

[0054] Note: The acid catalyst used in the above preparation is sulfuric acid.

[0055] Preparation Example 2

[0056] An organosilicon active particle, differing from preparation example 1, is prepared by the following steps:

[0057] Ethyl orthosilicate and hydroxypropyl methacrylate were mixed in a molar ratio of 1:3.5 and reacted under an acid catalyst at 75°C for 3 hours. During the reaction, the byproduct ethanol was continuously removed, and finally, organosilicon active particles were obtained.

[0058] Preparation Example 3

[0059] An organosilicon active particle, differing from preparation example 1, is prepared by the following steps:

[0060] Ethyl orthosilicate and hydroxypropyl methacrylate were mixed in a molar ratio of 1:4.5 and reacted under an acid catalyst at 80°C for 2 hours. During the reaction, the byproduct ethanol was continuously removed, and finally, organosilicon active particles were obtained.

[0061] Example

[0062] Example 1

[0063] A low-temperature curing high-efficiency electrophoretic paint, the components and their corresponding weights are shown in Table 1, and it is prepared by the following steps:

[0064] (1) Prepare raw materials containing epoxy resin, acrylic resin, curing agent, leveling agent, anti-settling agent and pigment filler according to the formula;

[0065] (2) Stir the epoxy resin and acrylic resin in step (1) at 500 r / min for 10 min, then add leveling agent, anti-settling agent and pigment filler during the stirring process, and then stir at 1200 r / min for 20 min and grind to 40 μm to obtain resin mixture.

[0066] (3) Stir and mix the resin mixture and curing agent in step (2) to obtain low-temperature curing high-efficiency electrophoretic paint.

[0067] Note: In the above steps, the curing agent is a modified imidazole compound, purchased from Adico EH-3293S; the leveling agent is a blend of polyether-modified organosilicon and fluorosilicone in a weight ratio of 3:5, wherein the fluorosilicone blend is a mixture of fluorinated siloxane and organosilicon leveling agent in a weight ratio of 1:2; the anti-settling agent is bentonite; the pigment filler is nano zinc oxide; the molecular weight of the epoxy resin is 600 Daltons; and the functional group content of the acrylic resin is 25 mg KOH / g.

[0068] Example 2-3

[0069] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the preparation components and their corresponding weights are shown in Table 1.

[0070] Table 1. Components prepared in Examples 1-3 and their weight parts (kg / part)

[0071] raw material Example 1 Example 2 Example 3 Epoxy resin 50 45 55 acrylic resin 40 35 45 curing agent 7.5 5 10 Leveling agent 1.5 1 2 Anti-settling agent 1.5 1 2 Pigment filler 7.5 5 10

[0072] Example 4

[0073] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the molecular weight of the epoxy resin is 400 Daltons.

[0074] Example 5

[0075] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the molecular weight of the epoxy resin is 800 Daltons.

[0076] Example 6

[0077] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the molecular weight of the epoxy resin is 350 Daltons.

[0078] Example 7

[0079] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the molecular weight of the epoxy resin is 850 Daltons.

[0080] Example 8

[0081] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the functional group content of the acrylic resin is 20 mg KOH / g.

[0082] Example 9

[0083] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the functional group content of the acrylic resin is 30 mg KOH / g.

[0084] Example 10

[0085] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the functional group content of the acrylic resin is 18 mg KOH / g.

[0086] Example 11

[0087] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the functional group content of the acrylic resin is 32 mg KOH / g.

[0088] Example 12

[0089] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that it also contains 0.6 parts by weight of ultraviolet curing additive, which is added together with the curing agent.

[0090] Example 13

[0091] A low-temperature curing high-efficiency electrophoretic paint differs from Example 12 in that it also contains 0.2 parts by weight of ultraviolet curing additive.

[0092] Example 14

[0093] A low-temperature curing high-efficiency electrophoretic paint differs from Example 12 in that it also contains one part by weight of ultraviolet curing additive.

[0094] Example 15

[0095] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the low-temperature curing high-efficiency electrophoretic paint also contains 1.5 parts by weight of functional additives. The functional additives are composed of organosilicon active particles and bismuth trioxide in a weight ratio of 3:1. The organosilicon active particles are obtained from Preparation Example 1. The functional additives are added together with leveling agents, anti-settling agents and pigment fillers.

[0096] Example 16

[0097] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the functional additives added are 1 part by weight.

[0098] Example 17

[0099] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the functional additives added are 2 parts by weight.

[0100] Example 18

[0101] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the functional additives are composed of organosilicon active particles and bismuth trioxide in a weight ratio of 3.5:1.

[0102] Example 19

[0103] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the functional additives are composed of organosilicon active particles and bismuth trioxide in a weight ratio of 2:1.

[0104] Example 20

[0105] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the functional additives are composed of organosilicon active particles and bismuth trioxide in a weight ratio of 5:1.

[0106] Example 21

[0107] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the organosilicon active particles are obtained from Preparation Example 2.

[0108] Example 22

[0109] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the organosilicon active particles are obtained from Preparation Example 3.

[0110] Example 23

[0111] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that the preparation components do not use organosilicon active particles.

[0112] Example 24

[0113] A low-temperature curing high-efficiency electrophoretic paint differs from Example 15 in that bismuth trioxide is not used in the preparation components.

[0114] Comparative Example

[0115] Comparative Example 1

[0116] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that, in the preparation components, 43 parts of epoxy resin and 47 parts of acrylic resin are used.

[0117] Comparative Example 2

[0118] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that, in the preparation components, 57 parts of epoxy resin and 33 parts of acrylic resin are used.

[0119] Comparative Example 3

[0120] A low-temperature curing high-efficiency electrophoretic paint differs from Example 1 in that the curing agent is an imidazole compound curing agent, specifically 2-phenylimidazolium.

[0121] Performance testing test samples: The low-temperature curing high-efficiency electrophoretic paint obtained in Examples 1-24 was used as test samples 1-24, and the low-temperature curing high-efficiency electrophoretic paint obtained in Comparative Examples 1-3 was used as control samples 1-3.

[0122] Experimental method: Electrophoresis was performed according to the requirements of GB1727-1992 "General Methods for Preparing Coating Films". The treated tinplate was connected to the electrodes and immersed in the coating. The electrophoresis parameters were: electrophoresis voltage 80V, electrophoresis time 30s, electrode spacing 10cm, and electrophoresis temperature 25℃.

[0123] (1) Curing temperature test of the paint film: The electrophoretic tinplate was placed in an oven and the minimum temperature required to form a stable paint film within a baking time of 0.5h was tested.

[0124] (2) Corrosion resistance test: The prepared paint film is immersed in a 5% sodium chloride solution at 80℃ for rapid corrosion. The time when corrosion spots appear on the surface of the coating film is observed and recorded, and the corrosion resistance is evaluated.

[0125] (3) Adhesion test: Use a scribing tool to score the sample surface, usually using a cross-grid method, that is, draw a set of mutually perpendicular straight lines in both the vertical and horizontal directions, stick the tape on the scored area, and tear it off with force. The adhesion of the paint film is evaluated by measuring the area of ​​residual paint on the tape. The smaller the area of ​​residual paint on the tape, the better the adhesion of the paint film.

[0126] (3) Film forming performance test: bubbles are one of the common defects of electrophoretic coatings, which will affect the smoothness and aesthetics of the electrophoretic coating; sagging refers to the vertical lines formed by the electrophoretic coating during the coating process; pinholes refer to the small holes formed in the electrophoretic coating; visual inspection is used, and pinholes can be detected with the help of a magnifying glass.

[0127] After completing the above tests on test samples 1-24 and control samples 1-3 in sequence, the corresponding results are recorded in Table 2.

[0128] Table 2 Test results of test samples 1-24 and control samples 1-3

[0129]

[0130]

[0131] As can be seen from Examples 1-3 and Comparative Examples 1-3, and Table 2, in the preparation of low-temperature curing high-efficiency electrophoretic paint, mixing epoxy resin and acrylic resin in a specific ratio range, and supplementing with a modified imidazole compound curing agent, can significantly reduce the curing temperature, reduce energy consumption, reduce environmental pollution, and ensure good film-forming properties, adhesion, and corrosion resistance of the electrophoretic paint. However, when the ratio of epoxy resin to acrylic resin exceeds the dosage range specified in this application, or when ordinary imidazole compound curing agents are used instead of modified imidazole compound curing agents, it is found that the minimum curing temperature of the electrophoretic paint cannot reach 125°C, but is instead the conventional 160°C. Furthermore, the corrosion resistance, adhesion, and film-forming performance tests are all poor, leading to a significant loss in the overall quality of the electrophoretic paint.

[0132] Combining Examples 1 and 4-7 with Table 2, it can be seen that when the molecular weight of the epoxy resin is 400-800 Daltons, the resulting low-temperature curing high-efficiency electrophoretic paint exhibits better film-forming properties, adhesion, and corrosion resistance during application. However, when the molecular weight of the epoxy resin is lower or higher than the above range, the performance of the low-temperature curing high-efficiency electrophoretic paint in corrosion resistance, adhesion, and film-forming properties will be compromised. Therefore, it is evident that epoxy resins with the above molecular weights can ensure the excellent stability of the low-temperature curing high-efficiency electrophoretic paint after application.

[0133] Combining Examples 1 and 8-9 with Table 2, it can be seen that the functional group content of acrylic resin is 20-30 mg KOH / g, which enables the obtained low-temperature curing high-efficiency electrophoretic paint to exhibit better film-forming properties, adhesion, and corrosion resistance during application. However, when the functional group content of acrylic resin is lower or higher than the above range, it will lead to a loss in the corrosion resistance, adhesion, and film-forming performance of the low-temperature curing high-efficiency electrophoretic paint. It can be seen that the acrylic resin with the above functional group content has better compatibility with other component raw materials after application, and can obtain a low-temperature curing high-efficiency electrophoretic paint with excellent and stable application quality.

[0134] As can be seen from Examples 1 and 12-14 and Table 2, the introduction of UV curing additives does not affect the overall performance of low-temperature curing high-efficiency electrophoretic paint. On the contrary, it can increase the conditions for rapid curing under UV light, which can greatly shorten the curing cycle.

[0135] As can be seen from Examples 1 and 15-22, and Table 2, the functional additives composed of specially prepared organosilicon active particles and secane trioxide can significantly improve the film-forming properties, adhesion, and corrosion resistance of electrophoretic paint at relatively low curing temperatures. Specifically, when the weight ratio of organosilicon active particles to secane trioxide is 3:1, the synergistic effect is better in the mixing system of the low-temperature curing high-efficiency electrophoretic paint, resulting in a better overall quality of the low-temperature curing high-efficiency electrophoretic paint. Furthermore, as can be seen from Examples 23-24 and Table 2, while using only organosilicon active particles or secane trioxide can improve film-forming properties, adhesion, and corrosion resistance under low-temperature curing conditions, the improvement effect is limited. Moreover, the sum of the improvement effects of using either alone is far less than the superior improvement effect of their combination. Therefore, the combination of organosilicon active particles and secane trioxide can bring a significant improvement effect of 1+1>2, which is beneficial for obtaining a low-temperature curing high-efficiency electrophoretic paint with better application quality.

[0136] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A low-temperature curing high-efficiency electrophoretic paint, characterized in that, It contains the following components in parts by weight: 45-55 parts epoxy resin; 35-45 parts acrylic resin; 5-10 parts of curing agent; 1-2 parts leveling agent; 1-2 parts anti-settling agent; 5-10 parts pigment filler; The curing agent is a modified imidazole compound; The epoxy resin has a molecular weight of 400-800 Daltons; The functional group content of the acrylic resin is 20-30 mg KOH / g; It also contains 1-2 parts by weight of functional additives, which are composed of organosilicon active particles and bismuth trioxide, and the weight ratio of organosilicon active particles to bismuth trioxide is (2-5):

1. The organosilicon active particles are prepared by the following steps: Ethyl orthosilicate and hydroxypropyl methacrylate were mixed in a molar ratio of 1:(3.5-4.5) and reacted under an acid catalyst at 75-80℃ for 2-3 hours. During the reaction, the byproduct ethanol was continuously removed, and finally, organosilicon active particles were obtained.

2. The low-temperature curing high-efficiency electrophoretic paint according to claim 1, characterized in that: The low-temperature curing high-efficiency electrophoretic paint also contains 0.2-1 parts by weight of ultraviolet curing additive.

3. The low-temperature curing high-efficiency electrophoretic paint according to claim 1, characterized in that: The leveling agent is a composite of polyether-modified organosilicon and fluorosilicone blend, wherein the fluorosilicone blend is composed of fluorinated siloxane and organosilicon leveling agent.

4. The low-temperature curing high-efficiency electrophoretic paint according to claim 1, characterized in that: The anti-settling agent is one or a combination of two of bentonite and fumed silica.

5. The low-temperature curing high-efficiency electrophoretic paint according to claim 1, characterized in that: The pigment filler is one or a combination of two of nano titanium dioxide and nano zinc oxide.

6. The low-temperature curing high-efficiency electrophoretic paint according to claim 1, characterized in that: The weight ratio of the organosilicon active particles to bismuth trioxide is 3:

1.

7. The preparation method of the low-temperature curing high-efficiency electrophoretic paint according to claim 1, characterized in that: Includes the following steps: (1) Prepare raw materials containing epoxy resin, acrylic resin, curing agent, leveling agent, anti-settling agent and pigment filler according to the formula; (2) Stir and mix the epoxy resin and acrylic resin in step (1), then add leveling agent, anti-settling agent and pigment filler during the stirring process, and then grind after stirring and mixing to obtain resin mixture; (3) Stir and mix the resin mixture and curing agent in step (2) to obtain low-temperature curing high-efficiency electrophoretic paint.

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