Preparation process and application of rare earth modified automobile metallic paint
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNER MONGOLIA UNIV OF SCI & TECH
- Filing Date
- 2026-06-05
- Publication Date
- 2026-07-03
Smart Images
Figure CN122326033A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of automotive metallic paint technology, specifically relating to a preparation process and application of rare earth modified automotive metallic paint. Background Technology
[0002] Automotive coating materials not only need to provide effective protection but also meet high aesthetic requirements. Automotive metallic paint, as an important type of coating material, introduces metallic pigments into the coating system, causing directional reflection under light conditions. This results in a comprehensive range of colors and brightness variations from different viewing angles, significantly enhancing the visual effect of the coating and leading to its widespread application in automotive surface coating.
[0003] However, the performance of metallic pigments in coating systems is closely related to their stability. Metal particles are prone to chemical reactions in aqueous or oxygen-containing environments, which may alter their surface properties, thus affecting the optical effects and long-term performance of the coating, such as gloss retention and color stability. Furthermore, the dispersion state of the metallic pigments in the coating system and their interfacial compatibility with the resin matrix also influence coating performance, including adhesion, weather resistance, and mechanical properties. Typically, additives or surface treatments of the metallic pigments are used to improve their dispersibility and stability.
[0004] Nevertheless, in practical applications, achieving a balance between coating stability, adhesion, and weather resistance while maintaining the optical effects of metallic pigments still presents considerable technical challenges. Summary of the Invention
[0005] The purpose of this invention is to provide a preparation process and application of rare earth modified automotive metallic paint, in order to solve the problems of high cost, low market promotion value, and difficulty in achieving multiple performances such as weather resistance and adhesion in the existing technology.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a preparation process for rare earth modified automotive metallic paint, comprising: a rare earth modifier preparation step: mixing cerium dioxide (CeO2) and lanthanum acetate (C6H9O6La) in a certain mass ratio to obtain a composite rare earth; adding the composite rare earth to an aqueous solution of a silane coupling agent to obtain a silane-treated dispersion system containing the composite rare earth; adding an additive containing a silicone defoamer, an anti-settling agent, and a leveling agent to the dispersion system, mixing and stirring, and ultrasonically dispersing to obtain a rare earth modifier; and an automotive metallic paint modification step: adding the rare earth modifier to the automotive metallic paint, stirring the mixture at a constant temperature, and then ultrasonically dispersing the mixture, allowing the ultrasonically dispersed emulsion to stand in the dark for full integration.
[0007] This invention modifies automotive metallic paint by using composite rare earth elements, which not only effectively inhibits the expansion and deterioration of the paint film under ultraviolet irradiation and significantly improves the adhesion of the paint film, but also effectively enhances the interfacial bonding strength between the coating and the substrate; at the same time, it improves the ultraviolet weather resistance and adhesion of the paint film, solving the problem that traditional automotive metallic paints cannot achieve multiple performances simultaneously.
[0008] Furthermore, the mass ratio of cerium dioxide to lanthanum acetate is 1:1 to 2:1; the mass ratio of the silicone defoamer, anti-settling agent, and leveling agent is 1:1:1.
[0009] Furthermore, the aqueous solution of the silane coupling agent is a mixture of deionized water and silane coupling agent in a mass ratio of 1:10.
[0010] Furthermore, the silane coupling agent is KH-560; the silicone defoamer is byk141; the anti-settling agent is byk410; and the leveling agent is byk306.
[0011] Furthermore, the mass percentages of the composite rare earth, the silane coupling agent aqueous solution, the additive, and the automotive metallic paint are: 4% composite rare earth, 30% silane coupling agent aqueous solution, 2% additive, and 64% automotive metallic paint. The mass ratio of deionized water to silane coupling agent in the silane coupling agent aqueous solution is 1:10.
[0012] Furthermore, the cerium dioxide is 20-50 nm in size and has a purity of 99.95%; the lanthanum acetate has a purity of 99%; and the automotive metallic paint includes resins containing active hydrogen.
[0013] Furthermore, in the rare earth modifier preparation step, the mixing and stirring specifically involves placing the mixture on a constant temperature magnetic stirrer and stirring for 40 to 60 minutes at 40±5℃ and 1800~2300rpm; the ultrasonic dispersion is carried out in an ultrasonic water bath at 40±5℃ for 60 to 90 minutes.
[0014] Furthermore, in the automotive metallic paint modification step, the constant temperature stirring of the mixture involves placing the mixture in a constant temperature magnetic stirrer and stirring for 45-60 minutes at 30±5℃ and 2000~2400rpm; the ultrasonic dispersion is carried out in an ultrasonic water bath at 30±5℃ for 40-60 minutes; and the light-protected standing is carried out for about 24 hours.
[0015] The present invention also provides a preparation process for rare earth modified automotive metallic paint and its application in paint film spraying.
[0016] This invention utilizes low-cost light rare earth resources such as cerium dioxide and lanthanum acetate in small quantities, while significantly improving UV resistance and enhancing paint film adhesion.
[0017] The rare earth modified automotive metallic paint obtained by this invention exhibits better color stability and maintains a high degree of color consistency under simulated long-term ultraviolet irradiation; it effectively enhances the interfacial bonding strength between the coating and the substrate; and it solves the problem that traditional automotive metallic paints struggle to achieve multiple performance characteristics.
[0018] This invention uses a water-based system combined with low-VOC additives, which is in line with the development trend of green coatings.
[0019] This invention achieves complementary performance advantages through synergistic effects and solves the problems of poor compatibility and limited functionality between single rare earth materials and metallic paints by using silane coupling agents for in-situ surface modification. This invention utilizes composite lanthanum ions (La... 3+ Together, they achieve excellent weather resistance and adhesion, thanks to La 3+ It is a hard cation. During the heating and stirring process of this invention, it can effectively generate a cross-linking effect similar to ionic clusters with polar groups such as hydroxyl (-OH) and carboxyl (-COOH) in the resin, thereby improving the density and hardness of the coating. At the same time, the three-dimensional cross-linking structure also restricts the movement of molecular chains and enhances the stability to changes in temperature and humidity. That is, the resin network is strengthened by the ionic cross-linking effect of compounded lanthanum acetate, making the coating denser and stronger.
[0020] The adhesion enhancement of this invention is based on: 1. One end of the silane coupling agent can react with the hydroxyl groups (-OH) on the surface of the inorganic substrate (the phosphated steel plate used in the example) to form a stable covalent bond (Si-O-metal). The other end can react with the active groups (such as hydroxyl, carboxyl, and epoxy groups) in the organic resin to form hydrogen bonds, creating a chemical bonding interface between the organic coating and the inorganic substrate, significantly improving adhesion. Specifically, the epoxy groups of KH-560 mainly undergo ring-opening addition reactions with resins containing active hydrogen (such as hydroxyl-containing acrylic resins, polyester resins, etc.), thereby forming chemical bonds. If other types of paint (such as non-polar polyolefin paints, fluorocarbon paints without active groups, etc.) lack functional groups that can effectively react with the silane coupling agent, a stable organic-inorganic interface cannot be formed, and the modifier is difficult to anchor in the resin network, resulting in the failure of adhesion enhancement.
[0021] 2. La 3+ La exhibits strong polarization ability; during heating and stirring, La... 3+ It can undergo ionic cluster crosslinking with polar groups such as -OH and -COOH in the resin to form a three-dimensional network structure, thereby enhancing the cohesive strength of the coating. 3+The ionic crosslinking process requires resin systems containing coordinating groups such as carboxyl and hydroxyl groups, such as automotive metallic paints, and the formation of ionic cluster networks under heating and stirring conditions. For paints that contain no or only a small number of polar groups (such as traditional nitrocellulose lacquer, chlorinated rubber lacquer, asphalt lacquer, etc.), La... 3+ It cannot produce an effective crosslinking density, and may instead cause the paint film to become brittle or have poor compatibility due to ion aggregation.
[0022] 3. Nano-sized CeO2 particles can be uniformly distributed in the coating, filling micropores and defects. Stable dispersion of nano-CeO2 particles requires the assistance of silane coupling agents and polar additives in the system (such as leveling agent BYK161). If other paint types use non-polar solvents (such as aromatics, mineral oils, etc.) or do not contain corresponding leveling agents, CeO2 will severely agglomerate, forming macroscopic defects, reducing the gloss and weather resistance of the paint film, and even causing coating peeling.
[0023] The modifier of this invention is designed to take into account the synergistic stabilizing effect with pigments such as metallic aluminum powder and pearlescent powder, and to inhibit the oxidation and discoloration of metallic pigments through rare earth surface modification. However, for ordinary or pure color paints without metallic pigments, this function of the modifier is not only redundant, but may also interfere with the original pigment dispersion state due to the introduction of rare earth ions, leading to problems such as floating color and blooming. Attached Figure Description
[0024] Figure 1 A picture showing a car metallic paint without rare earth modification applied to a phosphated steel sheet and left to stand for 3 days. Figure 2 This is a diagram of rare earth modified automotive metallic paint applied to a phosphated steel plate and left to stand for 3 days, as described in Example 1 of the present invention. Figure 3 This is a diagram of the rare earth modified automotive metallic paint of Example 3 of the present invention, which was sprayed onto a phosphated steel plate and left to stand for 3 days. Figure 4 This is a diagram of rare earth modified automotive metallic paint applied to a phosphated steel plate and left to stand for 3 days, as shown in Example 2 of the present invention. Figure 5 The image shows the results of a paint film adhesion test conducted using the pull-out method on a phosphated steel sheet to be coated with automotive metallic paint without rare earth modification. Figure 6 The image shows the results of a paint film adhesion test conducted using the pull-out method on a phosphated steel sheet coated with the rare earth modified automotive metallic paint of Example 1 of this invention. Figure 7 The image shows the results of a paint film adhesion test conducted using the pull-out method on a phosphated steel sheet coated with the rare earth modified automotive metallic paint of Example 3 of this invention. Figure 8 The image shows the results of a paint film adhesion test conducted using the pull-out method on a phosphated steel sheet coated with the rare earth modified automotive metallic paint of Example 2 of this invention. Figure 9 A comparative bar chart showing the overall color difference ΔE after 120 hours of ultraviolet light testing on phosphated steel sheets coated with automotive metallic paint without modified rare earth and phosphated steel sheets coated with rare earth modified automotive metallic paint of different proportions of the present invention. Figure 10 A bar chart comparing the hue angle change Δh after 120h and 360h of ultraviolet light testing on phosphated steel sheets coated with automotive metallic paint without modified rare earth elements and phosphated steel sheets coated with automotive metallic paint with modified rare earth elements of this invention. Figure 11 The a*b chromaticity diagrams of phosphated steel sheets coated with automotive metallic paint without rare earth modification and phosphated steel sheets coated with automotive metallic paint with rare earth modification of the present invention were obtained after 360 hours of ultraviolet light testing. Figure 12 The image shows the results of a pencil hardness test on a paint panel coated with automotive metallic paint without rare earth modifiers using a 5H pencil. Figure 13 The image shows the results of a pencil hardness test on a paint panel coated with automotive metallic paint without rare earth modifiers using a 4H pencil. Figure 14 The image shows the result of a pencil hardness test on the paint plate of the automotive metallic paint of Example 2 using a 5H pencil. Figure 15 The image shows the result of a pencil hardness test on the paint plate of the automotive metallic paint of Example 1 using a 5H pencil. Figure 16 The image shows the result of a pencil hardness test on the paint plate of the automotive metallic paint of Example 3 using a 5H pencil. Figure 17 The results of a 120-hour neutral salt spray test on a panel coated with automotive metallic paint without rare earth modification. Figure 18 The result of a neutral salt spray test for 120 hours on a panel coated with the automotive metallic paint of Example 2. Figure 19 The result of a neutral salt spray test for 120 hours on a panel coated with the automotive metallic paint of Example 3. Figure 20 The result of a neutral salt spray test for 120 hours on a panel coated with the automotive metallic paint of Example 1. Figure 21 Results of a 360-hour neutral salt spray test on a panel coated with automotive metallic paint without rare earth modification. Figure 22 The result of a 360-hour neutral salt spray test on a panel coated with the automotive metallic paint of Example 2. Figure 23The result of a 360-hour neutral salt spray test on a panel coated with the automotive metallic paint of Example 3. Figure 24 The image shows the results of a 360-hour neutral salt spray test on a panel coated with the automotive metallic paint of Example 1. Detailed Implementation
[0025] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0026] The automotive metallic paint used in the experiments of this invention embodiment is Koloch White K-112 metallic paint.
[0027] Example 1 First, weigh 0.8g of nano-cerium oxide and 0.4g of lanthanum acetate. Add the weighed composite rare earth raw materials to a mixture of 1.6g of deionized water and 16g of silane coupling agent (KH-560). Then add 0.4g of silicone defoamer (byk141), 0.4g of anti-settling agent (byk410), and 0.4g of leveling agent (byk161). Place the mixture on a constant temperature magnetic stirrer and stir for 40 minutes at 40℃ and 2100rpm to obtain a milky yellow solution.
[0028] The mixed solution was transferred to an ultrasonic water bath for ultrasonic dispersion for 90 minutes to obtain the rare earth modifier.
[0029] Add the rare earth modifier to 80 ml of automotive metallic paint. Place the resulting mixture in a constant temperature magnetic stirrer and stir for 60 min at 30℃ and 2300 rpm to obtain a preliminary mixed rare earth modified automotive metallic paint. Then, place the preliminary mixed automotive metallic paint into an ultrasonic water bath for ultrasonic dispersion for 50 min. After that, transfer the mixture to a dark place and let it stand for 24 h to allow the rare earth modifier to fully integrate with the automotive metallic paint. After 24 h, the rare earth modified automotive metallic paint is obtained.
[0030] The modified rare earth automotive metallic paint was thoroughly mixed with 60ml of standard dry thinner. The diluted automotive metallic paint was then evenly sprayed onto a phosphated steel plate used for paint testing in a dust-free environment. The phosphated steel plate coated with the automotive metallic paint was then left to stand in a dust-free environment for 3 days. Figure 2 As shown.
[0031] Example 2 First, weigh 0.4g of nano-cerium oxide and 0.4g of lanthanum acetate. Add the weighed composite rare earth raw materials to a mixture of 1.6g of deionized water and 16g of silane coupling agent (KH-560). Then add 0.4g of silicone defoamer (byk141), 0.4g of anti-settling agent (byk410), and 0.4g of leveling agent (byk161). Place the mixture on a constant temperature magnetic stirrer and stir for 40 minutes at 40℃ and 2100rpm to obtain a milky yellow solution.
[0032] The mixed solution was transferred to an ultrasonic water bath for ultrasonic dispersion for 90 minutes to obtain the rare earth modifier.
[0033] Add the rare earth modifier to 80 ml of automotive metallic paint. Place the resulting mixture in a constant temperature magnetic stirrer and stir for 60 min at 30℃ and 2300 rpm to obtain a preliminary mixed rare earth modified automotive metallic paint. Then, place the preliminary mixed automotive metallic paint into an ultrasonic water bath for ultrasonic dispersion for 50 min. After that, transfer the mixture to a dark place and let it stand for 24 h to allow the rare earth modifier to fully integrate with the automotive metallic paint. After 24 h, the rare earth modified automotive metallic paint is obtained.
[0034] The modified rare earth automotive metallic paint was thoroughly mixed with 60ml of standard dry thinner. The diluted automotive metallic paint was then evenly sprayed onto a phosphated steel plate used for paint testing in a dust-free environment. The phosphated steel plate coated with the automotive metallic paint was then left to stand in a dust-free environment for 3 days. Figure 4 As shown.
[0035] Example 3 First, weigh 0.6g of nano-cerium oxide (CeO2, 20~50nm, 99.95%) and 0.4g of lanthanum acetate (C6H9O6La, 99.9%). Add the weighed composite rare earth raw materials to a mixture of 1.6g of deionized water and 16g of silane coupling agent (KH-560). Then add 0.4g of silicone defoamer (byk141), 0.4g of anti-settling agent (byk410), and 0.4g of leveling agent (byk161). Place the mixture on a constant temperature magnetic stirrer and stir for 40min at 40℃ and 2100rpm to obtain a milky yellow solution.
[0036] The mixed solution was transferred to an ultrasonic water bath for ultrasonic dispersion for 90 minutes to obtain the rare earth modifier.
[0037] Add the rare earth modifier to 80 ml of automotive metallic paint. Place the resulting mixture in a constant temperature magnetic stirrer and stir for 60 min at 30℃ and 2300 rpm to obtain a preliminary mixed rare earth modified automotive metallic paint. Then, place the preliminary mixed automotive metallic paint into an ultrasonic water bath for ultrasonic dispersion for 50 min. After that, transfer the mixture to a dark place and let it stand for 24 h to allow the rare earth modifier to fully integrate with the automotive metallic paint. After 24 h, the rare earth modified automotive metallic paint is obtained.
[0038] The modified rare earth automotive metallic paint was thoroughly mixed with 60ml of standard dry thinner. The diluted automotive metallic paint was then evenly sprayed onto a phosphated steel plate used for paint testing in a dust-free environment. The phosphated steel plate coated with the automotive metallic paint was then left to stand in a dust-free environment for 3 days. Figure 3 As shown.
[0039] Performance tests were conducted on Examples 1 to 3 and the original paint (metallic paint without rare earth modifiers): like Figures 1 to 4 As shown, after 3 days of spraying, the original paint and the rare earth modified automotive metallic paint of the present invention show a significant improvement in smoothness and flatness.
[0040] Performance tests were conducted on the rare earth-modified automotive metallic paints of Examples 1 to 3: the results are as follows Figure 5 As shown in the figure, the results of the paint film adhesion test on the phosphated steel sheet coated with automotive metallic paint without rare earth modification were obtained using the pull-out method. The average paint film adhesion was measured to be 1.755 MPa. Figure 6 As shown in the figure, the phosphated steel sheet coated with rare earth modified automotive metallic paint of Example 1 was subjected to an end-of-term adhesion test using the pull-out method. The average adhesion strength of the paint film was measured to be 2.20 MPa. like Figure 7 As shown in the figure, the phosphated steel sheet coated with the rare earth modified automotive metallic paint of Example 3 underwent a final adhesion test using the pull-out method. The average adhesion strength of the paint film was measured to be 2.145 MPa. Figure 8 As shown in the figure, the phosphated steel sheet coated with rare earth modified automotive metallic paint of Example 2 was subjected to an end-of-term adhesion test using the pull-out method. The average adhesion strength of the paint film was measured to be 1.88 MPa.
[0041] like Figure 9As shown in the bar chart, the overall color difference ΔE of phosphated steel sheets coated with automotive metallic paint without modified rare earth elements and those coated with rare earth modified automotive metallic paints of different proportions as shown in Examples 1 to 3 of this invention were compared after 120 hours of ultraviolet light testing. The results show that the overall color difference of the phosphated steel sheet coated with the rare earth modified automotive metallic paint of Example 3 (0.071) is much smaller than that of the phosphated steel sheet coated with the paint without modified rare earth elements (0.276). The overall color difference of the phosphated steel sheet coated with the rare earth modified automotive metallic paint of Example 2 (0.152) is also smaller than that of the original metallic paint (0.276), but the effect is not as good as that of the rare earth modified automotive metallic paint of Example 1.
[0042] like Figure 10 The bar chart shows the hue angle change Δh of the phosphated steel sheet coated with automotive metallic paint without modified rare earth and the phosphated steel sheet coated with automotive metallic paint of Examples 1 to 3 after 120h and 360h of ultraviolet light testing. The results show that the hue angle change of the phosphated steel sheet coated with 2:1 rare earth modified automotive metallic paint is smaller.
[0043] like Figure 11 As shown, the a*b chromaticity diagrams of phosphated steel sheets coated with automotive metallic paint without rare earth modification and those coated with automotive metallic paint of Example 1 were obtained after 360 hours of ultraviolet light testing. The color trajectory results show that the trajectory of the phosphated steel sheet coated with automotive metallic paint with added rare earth is more concentrated, indicating that the color is more stable.
[0044] like Figure 12 The image shows a picture after a pencil hardness test was performed on a paint panel coated with unmodified automotive metallic paint using a 5H pencil. The results show that there were obvious scratches on the paint panel, indicating that the hardness of the paint film without rare earth modification did not reach the hardness of a 5H pencil. Figure 13 The image shows the result of a pencil hardness test on a paint panel coated with unmodified automotive metallic paint using a 4H pencil. The results show no obvious scratches on the paint panel, indicating that the hardness of the unmodified automotive metallic paint film is 4H. Figure 14 The image shown is a picture of the paint film of the automotive metallic paint of Example 2 after a pencil hardness test using a 5H pencil; the results show that there are no obvious scratches on the paint film, that is, the paint film hardness of the automotive metallic paint of Example 2 of this invention is 5H. Figure 15 The image shown is a picture of the paint film of the automotive metallic paint of Example 1 after a pencil hardness test using a 5H pencil; the results show that there are no obvious scratches on the paint film, that is, the paint film hardness of the automotive metallic paint of Example 1 is 5H. Figure 16 The image shown is a picture of the paint plate of the automotive metallic paint of Example 3 after a pencil hardness test using a 5H pencil; the results show that there are no obvious scratches on the paint plate, that is, the paint film hardness of the rare earth modified automotive metallic paint of Example 3 is 5H.
[0045] like Figure 17 As shown, the results of a 120-hour neutral salt spray test were conducted on a panel coated with automotive metallic paint without rare earth modification. Figure 18 As shown, the results of a neutral salt spray test for 120 hours were conducted on a panel coated with the rare earth-modified automotive metallic paint of Example 2; Figure 19 As shown, the results of a 120-hour neutral salt spray test were conducted on the painted panel of Example 3. Figure 20 The results of a neutral salt spray test for 120 hours were obtained from the paint panel of the automotive metallic paint of Example 1 shown. like Figure 21 The image shows the results of a 360-hour neutral salt spray test on a panel coated with automotive metallic paint without rare earth modification. Figure 22 The image shows the results of a neutral salt spray test after 360 hours on a panel coated with the rare earth-modified automotive metallic paint of Example 2. Figure 23 The image shows the results of a 360-hour neutral salt spray test on a panel coated with the rare earth-modified automotive metallic paint of Example 3. Figure 24 The image shows the results of a 360-hour neutral salt spray test on a panel coated with the metallic paint of Example 1. Figures 17 to 20 Results of a 120-hour neutral salt spray test and from Figures 21 to 24 The results of the 360-hour neutral salt spray test show that the embodiments of the present invention have excellent corrosion resistance. Table 1 shows the rust grades (ISO4628-3) of the painted panels with different proportions after the 120-hour neutral salt spray test; Table 2 shows the rust grades (ISO4628-3) of the painted panels with different proportions after the 360-hour neutral salt spray test.
[0046] Table 1. Rust levels of painted panels with different proportions after 120h neutral salt spray test.
[0047] Table 2. Rust levels of painted panels with different proportions after 360h neutral salt spray test. .
Claims
1. A preparation process for rare earth modified automotive metallic paint, characterized in that, include: Preparation steps of rare earth modifier: Cerium dioxide and lanthanum acetate are mixed in a certain mass ratio to obtain composite rare earth; The composite rare earth is added to an aqueous solution of a silane coupling agent to obtain a silane-treated dispersion system containing the composite rare earth; additives containing a silicon defoamer, an anti-settling agent, and a leveling agent are added to the dispersion system, and the mixture is stirred and ultrasonically dispersed to obtain a rare earth modifier. Modification steps for automotive metallic paint: The rare earth modifier is added to the automotive metallic paint, and after constant temperature stirring, it is ultrasonically dispersed and then allowed to stand in the dark to obtain rare earth modified automotive metallic paint.
2. The preparation process of a rare earth modified automotive metallic paint according to claim 1, characterized in that, The mass ratio of cerium dioxide to lanthanum acetate is 1:1 to 2:
1.
3. The preparation process of a rare earth modified automotive metallic paint according to claim 1, characterized in that, The mass ratio of the silicone-containing defoamer, anti-settling agent, and leveling agent is 1:1:
1.
4. The preparation process of a rare earth modified automotive metallic paint according to claim 1, characterized in that, The aqueous solution of the silane coupling agent is a mixture of deionized water and silane coupling agent in a mass ratio of 1:
10.
5. The preparation process of a rare earth modified automotive metallic paint according to claim 1, characterized in that, The silane coupling agent is KH-560; the silicone defoamer is byk141; the anti-settling agent is byk410; and the leveling agent is byk306.
6. The preparation process of a rare earth modified automotive metallic paint according to any one of claims 1 to 5, characterized in that, The mass percentages of the composite rare earth, the silane coupling agent aqueous solution, the additive, and the automotive metallic paint are: 4% composite rare earth, 30% silane coupling agent aqueous solution, 2% additive, and 64% automotive metallic paint.
7. The preparation process of a rare earth modified automotive metallic paint according to claim 5, characterized in that, The cerium dioxide is 20-50 nm in size and has a purity of 99.95%; the lanthanum acetate has a purity of 99%; and the automotive metallic paint includes a resin containing active hydrogen.
8. The preparation process of a rare earth modified automotive metallic paint according to claim 5, characterized in that, In the rare earth modifier preparation step, the stirring is carried out at 40±5℃ and a speed of 1800~2300rpm for 40~60 minutes; the ultrasonic dispersion is carried out at 40±5℃ for 60~90 minutes, followed by cooling to room temperature.
9. The preparation process of a rare earth modified automotive metallic paint according to claim 5, characterized in that, In the automotive metallic paint modification step, the stirring is carried out at 30±5℃ and 2000~2400rpm for 45~60 minutes; the ultrasonic dispersion is carried out at 30±5℃ for 40~60 minutes; and the light-protected standing is carried out for 20~30 hours.
10. The application of a rare earth modified automotive metallic paint prepared by the preparation process of any one of claims 1 to 9 in paint film spraying.