Vehicle body coating method and coating structure used in low-temperature cold climate
By adopting enhanced body coating methods in low-temperature cold zone climates, including electrophoretic auxiliary electrodes and multi-layer coating technology, the corrosion problem of the car body in ice and snow weather is solved, and the protection effect and freezing resistance are significantly improved.
Patent Information
- Application Number
- CN202411830282.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-03-18
AI Technical Summary
The prior art is difficult to effectively prevent car body corrosion in low-temperature cold zone climates, especially in ice and snowy weather and marine climate conditions, early rust is prone to occur on the bottom of the car body and skirt.
A coating method including pretreatment, electrophoresis, spray protective layer, medium paint, topcoat and hydrophobic layer is adopted. This method increases the anticorrosion performance and freezing ability of the vehicle body by adding electrophoretic auxiliary electrodes inside the vehicle body to form an electrophoretic layer with a larger thickness, and spraying protective layer and hydrophobic layer outside the electrophoretic layer.
It effectively improves the protective effect of the bottom of the car body and skirt, avoids early rust, and reduces the risk of snow freezing on the outer skirt of the car body in ice and snow, reducing the corrosion of snow melting agent on the skirt.
Smart Images
Figure CN119640370A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of commercial vehicle body anticorrosion, and in particular relates to a vehicle body painting method and a coating structure for use in low-temperature cold climates. Background Art
[0002] More and more commercial vehicles are going abroad and facing different environments in different regions of the world. In order to prevent the corrosion of the vehicle body, especially in the Nordic region with low temperature, ice and snow, and marine climate, extremely high requirements are placed on the vehicle body anti-corrosion process.
[0003] At present, commercial vehicles exported to Norway and other Nordic regions are thin-shell bodies with full stamping structures, and adopt the same anti-corrosion process as passenger cars. After cold-rolled plate stamping and welding, spraying electrophoresis, spraying topcoat and other processes are widely used, but there are still the following shortcomings: At present, the thickness of the electrophoretic paint film on the outside and inside of the car body has improved the anti-corrosion performance to a certain extent. However, it is still difficult to meet the requirements in an environment where roads with a large amount of de-icing agents are used in a low-temperature snowy climate and a marine climate are superimposed. When the car body faces snowy weather and roads with a large amount of de-icing agents, a large amount of ice and snow containing de-icing agents will freeze on the lower skirt of the car body, which will cause early rust on the skirt of the car body.
[0004] In addition, due to the sharp edge effect of electrophoretic paint, the electrophoretic paint film on the folded edges and process holes is relatively thin. Due to the existence of the sharp edge effect, it is difficult for general vehicles to achieve long-term use without rust. Summary of the invention
[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a vehicle body painting method and coating structure for use in low-temperature cold climates, so as to solve the problem of poor anti-corrosion effect of vehicle bodies in cold climates. The technical solution of the present invention to solve the above technical problems is as follows: a method for coating a vehicle body in a low-temperature cold climate, the coating method comprising the following steps: S1. Pre-treat the vehicle body and add electrophoresis auxiliary electrodes inside the vehicle body; S2, performing electrophoresis on the vehicle body to form an electrophoretic layer; S3. Spray a protective layer on the bottom of the vehicle body and the inner side of the skirt; S4. After polishing the car body, spray the intermediate paint to form the intermediate coating; S5, after polishing the car body, spraying topcoat to form a topcoat layer; S6. Spray a hydrophobic coating on the outer surface of the skirt of the vehicle body to form a hydrophobic layer.
[0006] Compared with the prior art, the above technical solution has the following beneficial effects: By directly spraying the protective layer after forming the electrophoretic layer, the protective layer covers the bottom of the vehicle body and the inner side of the skirt, thereby improving the protective effect of the bottom of the vehicle and avoiding the problem of easy rust on the folded edge of the bottom of the vehicle. At the same time, the hydrophobic layer sprayed on the outside of the topcoat layer can utilize the hydrophobicity to make this part less likely to freeze, reduce the amount of snow freezing on the outside skirt of the vehicle body in icy and snowy weather conditions, and reduce the corrosion of the skirt by the snow-melting agent in the ice and snow.
[0007] Furthermore, step S2 is specifically that the thickness of the electrophoretic layer on the outer surface of the vehicle body is ≥30 μm, the thickness of the electrophoretic layer on the inner surface of the vehicle body is ≥25 μm, and the thickness of the electrophoretic layer in the cavity of the vehicle body is ≥15 μm.
[0008] Furthermore, step S3 specifically includes: The nano anti-corrosion coating is sprayed on the bottom of the vehicle and the inner side of the skirt to form an anti-corrosion coating to cover the bottom folded edge and the edge of the process hole. The dry film thickness of the anti-corrosion coating is ≥100μm.
[0009] Furthermore, step S3 further includes: Apply sealant to the gaps and holes on the bottom of the vehicle, and then spray anti-impact paint on the bottom of the vehicle, the inner side of the skirt and the lower part of the wheel cover to form an anti-impact layer, the dry film thickness of the anti-impact layer is 1-2mm.
[0010] Furthermore, step S5 specifically includes: Grind the middle coating and spray the topcoat on the outer surface of the car body to form a topcoat layer; Polish the topcoat layer and spray clearcoat on the outer surface of the vehicle body to form a clearcoat layer; The total thickness of the paint film on the outer surface of the vehicle body, including the electrophoretic layer, mid-coat layer, topcoat layer and clear coat layer, is not less than 150μm.
[0011] Furthermore, after step S6, the method further includes: spraying anti-corrosion wax on the vehicle bottom and the cavities of the skirt and drying the wax naturally, wherein the dry film thickness of the anti-corrosion wax is not less than 50 μm.
[0012] This embodiment also discloses a coating structure obtained according to the above-mentioned vehicle body painting method, which comprises: Electrophoretic layer, applied to the interior and exterior surfaces of the vehicle body; A protective layer, applied on the electrophoretic layer on the bottom of the vehicle body and the inner side of the skirt of the vehicle body; A middle coating layer, applied on the electrophoretic layer on the outer surface of the vehicle body; A topcoat layer, applied on the middle coating layer; A hydrophobic layer is coated on the topcoat layer on the outer surface of the skirt of the vehicle body.
[0013] In one embodiment, the protective layer includes an anti-corrosion coating and an impact-resistant layer.
[0014] In one embodiment, the topcoat layer comprises: a topcoat base layer; The varnish layer is applied on the polished surface of the topcoat base layer.
[0015] In one embodiment, the surface energy of the hydrophobic layer is no more than 40 mN / m, and the contact angle of the hydrophobic layer is no less than 130°.
[0016] Based on the above technical solution, the embodiment of the present application can also be improved as follows: One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. By spraying a hydrophobic layer on the outside of the car body group, this part is not easy to freeze. Even if it freezes, the ice layer frozen on the surface of the hydrophobic coating is particularly easy to remove, reducing the corrosion of the skirt by the snow-melting agent in the ice and snow.
[0017] 2. By adding auxiliary electrode equipment, the paint film thickness on the inner and outer surfaces of the vehicle body and in the body cavity is greatly increased during electrophoresis, thereby improving the anti-corrosion performance of the entire vehicle.
[0018] 3. The double protective layer formed by the anti-corrosion coating and the impact-resistant layer sprayed outside the electrophoretic layer effectively avoids the rust problem caused by the folding edge of the vehicle bottom. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0020] Figure 1 It is a schematic diagram of the overall process of the present invention.
[0021] Figure 2 This is a schematic diagram of the structure of Example 2 of the present invention.
[0022] Reference numerals: 1. Car body; 2. Electrophoretic layer; 3. Anti-corrosion coating; 4. Impact-resistant layer; 5. Middle coating; 6. Topcoat base layer; 7. Clear varnish layer; 8. Hydrophobic layer. DETAILED DESCRIPTION
[0023] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention. It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the invention belongs.
[0024] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0025] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.
[0026] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0027] The present invention aims at the shortcomings of the existing vehicle body anti-corrosion process to meet the 10-year anti-corrosion requirements in low-temperature cold climates. The salt spray resistance of all coatings is set to ≮2000 hours. In order to adapt to the special requirements of high humidity, high salt, and high snowmelt environment for vehicle anti-corrosion, the whole vehicle is strengthened with anti-corrosion, especially the bottom prone to corrosion area adopts enhanced anti-corrosion technology to ensure that no structural corrosion occurs during the whole life cycle of the vehicle. In order to solve the above shortcomings, it is ensured that the salt spray resistance of each prone to corrosion part of the whole vehicle is ≮2000 hours.
[0028] Example 1 like Figure 1 As shown, the present invention provides a vehicle body painting method for low-temperature cold climates, the painting method comprising the following steps: Step S1, pre-treating the vehicle body and adding an electrophoresis auxiliary electrode inside the vehicle body; At present, the whole vehicle generally adopts the cathode electrophoresis process. During electrophoresis, auxiliary anode equipment is added inside the vehicle body. If the anodic electrophoresis process is adopted, auxiliary cathode equipment is added inside the vehicle body accordingly. The specific position is that the auxiliary anode is suspended inside the vehicle body so that the auxiliary anode and the inner surface of the vehicle body are kept relatively close. At the same time, auxiliary anode equipment can be supplemented at the position where reinforcement is needed.
[0029] Step S2, performing electrophoresis on the vehicle body to form an electrophoretic layer; During electrophoresis, due to the added auxiliary electrodes, the thickness of the electrophoretic paint film on the outer surface, inner surface and inside the body cavity can be increased. Specifically, the thickness of the electrophoretic paint film on the outer surface of the body is ≥30μm, the thickness of the electrophoretic paint film on the inner surface of the body is ≥25μm, and the thickness of the electrophoretic paint film in the body cavity is ≥15μm, which greatly improves the anti-corrosion performance of the entire vehicle.
[0030] Step S3, spraying a protective layer on the bottom of the vehicle body and the inner side of the skirt; Specifically, the protective layer includes an anti-corrosion coating and an impact-resistant layer; After electrophoresis, the anti-corrosion coating is sprayed by spraying a two-component 8000 series nano anti-corrosion coating on the lower surface of the vehicle bottom and the inner surface of the skirt to form an anti-corrosion coating to cover the bottom fold and the edge of the process hole. The dry film thickness of the anti-corrosion coating is ≥100μm. The coating is salt spray resistant for ≮3000 hours (when the thickness of the anti-corrosion coating is 80-100μm) and has excellent matching with the electrophoretic paint. Specifically, the adhesion between the anti-corrosion coating and the electrophoretic paint film meets level 0, and there is no problem of biting the bottom of the electrophoretic paint. At the same time, the performance does not change after baking at 150℃ for 5 hours, and it can be used in high-temperature systems.
[0031] The problem of early rust of the electrophoretic paint film on the folded edges and process hole edges of the vehicle bottom has been solved.
[0032] The impact-resistant layer is then sprayed by applying PVC sealant to the gaps and holes on the bottom of the vehicle to prevent water leakage and dust leakage and to form a seal for the vehicle body. Then, PVC impact-resistant paint is sprayed on the bottom of the vehicle, the inner side of the skirt and the lower part of the wheel arch to form an impact-resistant layer. The dry film thickness of the impact-resistant layer is 1mm-2mm, and it is specifically baked at 140±5℃ for 0.5h.
[0033] Step S4, after polishing the vehicle body, spraying a mid-coat paint to form a mid-coat layer; After spraying the impact-resistant paint on the bottom of the car, the uneven defects of the car body are repaired and polished, and then the middle coating is sprayed on the outer surface of the car body, including the door frame and the inner side of the door to form a middle coating. The dry film thickness of the middle coating is 40-60μm, and it is baked at 140±5℃ for 0.5h.
[0034] Step S5, spraying topcoat after polishing the vehicle body to form a topcoat layer; Specifically, the middle coating is firstly polished off by about 5 μm, and a topcoat is sprayed on the outer surface of the vehicle body to form a topcoat layer; After that, the topcoat layer is polished, and a varnish is sprayed on the outer surface of the vehicle body to form a varnish layer. Specifically, the varnish layer is baked at 140±5℃ for 0.5h; Among them, after spraying the topcoat layer, a color paint layer can be sprayed between the topcoat layer and the clear varnish layer according to needs.
[0035] The total thickness of the paint film on the entire outer surface of the vehicle body, including the electrophoretic layer, mid-coat layer, topcoat layer and clear coat layer, is not less than 150μm, of which the electrophoretic layer is about 30μm, the mid-coat layer after polishing is about 35μm, the topcoat layer is about 50μm, and the clear coat layer is about 40μm. While ensuring the corrosion protection of the entire vehicle's outer surface, the appearance of the vehicle body paint film is also improved. The DOI of the entire vehicle paint film is ≥88.
[0036] Step S6: spraying a hydrophobic coating on the outer surface of the skirt of the vehicle body to form a hydrophobic layer.
[0037] Specifically, after the vehicle body is painted, before it is transferred to the final assembly, a layer of nano-hydrophobic coating is added to the outer surface of the body skirt to form a hydrophobic layer. The dry film thickness of the hydrophobic layer is 40-50μm. Specifically, it is baked at 70±5℃ for 1h. The contact angle of the nano-hydrophobic coating is not less than 130°, about 133.3°, and the surface energy is not more than 40 mN / m, about 35.2mN / m. It has significant hydrophobicity and is not easy to freeze. Even if it freezes, the ice layer frozen on the surface of the hydrophobic coating is particularly easy to remove. Reduce the amount of snow frozen on the body skirt in icy and snowy weather conditions, and reduce the corrosion of the skirt by the snow-melting agent in the ice and snow.
[0038] By directly spraying the protective layer after forming the electrophoretic layer, the protective layer covers the bottom of the vehicle body and the inner side of the skirt, thereby improving the protective effect of the bottom of the vehicle and avoiding the problem of easy rust on the folded edge of the bottom of the vehicle. At the same time, the hydrophobic layer sprayed on the outside of the topcoat layer can utilize the hydrophobicity to make this part less likely to freeze, reduce the amount of snow freezing on the outside skirt of the vehicle body in icy and snowy weather conditions, and reduce the corrosion of the skirt by the snow-melting agent in the ice and snow.
[0039] After step S6, the method further includes: spraying anti-corrosion wax on the vehicle bottom and the cavities of the skirt and letting it dry naturally, wherein the dry film thickness of the anti-corrosion wax is not less than 50 μm.
[0040] After final assembly, the chassis is sprayed with anti-corrosion wax.
[0041] Example 2 like Figure 2 As shown, this embodiment also discloses a coating structure, which is obtained according to the vehicle body 1 painting method in Example 1, and the coating structure includes: an electrophoretic layer 2, a protective layer, a middle coating layer 5, a topcoat layer and a hydrophobic layer 8 coated in sequence from the inside to the outside.
[0042] The electrophoretic layer 2 is coated on the inner and outer surfaces of the vehicle body 1 and the cavity of the frame. By adding auxiliary anodes, the paint film thickness of the electrophoretic layer 2 is increased to meet the target requirements.
[0043] The protective layer is coated on the electrophoretic layer 2 at the bottom of the vehicle body 1 and the inner side of the skirt of the vehicle body 1. Specifically, the protective layer includes an anti-corrosion coating and an impact-resistant layer 4. The anti-corrosion coating is coated on the bottom of the vehicle and the inner side of the skirt, and the impact-resistant layer 4 is coated on the bottom of the vehicle, the inner side of the skirt and the lower part of the wheel arch.
[0044] The middle coating layer 5 is coated on the electrophoretic layer 2 on the outer surface of the vehicle body 1; the topcoat layer is coated on the middle coating layer 5, and the topcoat layer includes: a topcoat base layer 6 and a clearcoat layer 7, and the clearcoat layer 7 is coated on the topcoat base layer 6 after surface polishing.
[0045] The hydrophobic layer 8 is coated on the top paint layer on the outer surface of the skirt of the vehicle body 1 .
[0046] Specifically, the surface energy of the hydrophobic layer 8 is not more than 40 mN / m, and the contact angle of the hydrophobic layer 8 is not less than 130°.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for painting a vehicle body in a low-temperature cold climate, characterized in that: The coating method comprises the following steps: S1. Pre-treat the vehicle body and add electrophoresis auxiliary electrodes inside the vehicle body; S2, performing electrophoresis on the vehicle body to form an electrophoretic layer; S3. Spray a protective layer on the bottom of the vehicle body and the inner side of the skirt; S4. After polishing the car body, spray the intermediate paint to form the intermediate coating; S5, after polishing the car body, spraying topcoat to form a topcoat layer; S6. Spray a hydrophobic coating on the outer surface of the skirt of the vehicle body to form a hydrophobic layer.
2. The vehicle body painting method according to claim 1, characterized in that: Specifically, step S2 comprises that the thickness of the electrophoretic layer on the outer surface of the vehicle body is ≥30 μm, the thickness of the electrophoretic layer on the inner surface of the vehicle body is ≥25 μm, and the thickness of the electrophoretic layer in the cavity of the vehicle body is ≥15 μm.
3. The vehicle body painting method according to claim 1, characterized in that: Step S3 specifically includes: The nano anti-corrosion coating is sprayed on the bottom of the vehicle and the inner side of the skirt to form an anti-corrosion coating to cover the bottom folded edge and the edge of the process hole. The dry film thickness of the anti-corrosion coating is ≥100μm.
4. The vehicle body painting method according to claim 3, characterized in that: Step S3 also includes: Apply sealant to the gaps and holes on the bottom of the vehicle, and then spray impact-resistant paint on the bottom of the vehicle, the inner side of the skirt and the lower part of the wheel cover to form an impact-resistant layer, and the dry film thickness of the impact-resistant layer is 1-2mm.
5. The vehicle body painting method according to claim 1, characterized in that: Step S5 specifically includes: Grind the middle coating and spray the topcoat on the outer surface of the car body to form a topcoat layer; Polish the topcoat layer and spray clearcoat on the outer surface of the vehicle body to form a clearcoat layer; Among them, the total thickness of the paint film on the outer surface of the vehicle body, including the electrophoretic layer, mid-coat layer, topcoat layer and clear varnish layer, is not less than 150μm.
6. The vehicle body painting method according to claim 1, characterized in that: After step S6, the method further includes: spraying anti-corrosion wax on the vehicle bottom and the cavities of the skirt and letting it dry naturally, wherein the dry film thickness of the anti-corrosion wax is not less than 50 μm.
7. A coating structure obtained by the vehicle body painting method according to any one of claims 1 to 6, characterized in that: include: Electrophoretic layer, applied to the interior and exterior surfaces of the vehicle body; A protective layer, applied on the electrophoretic layer on the bottom of the vehicle body and the inner side of the skirt of the vehicle body; A middle coating layer, applied on the electrophoretic layer on the outer surface of the vehicle body; A topcoat layer, applied on the middle coating layer; A hydrophobic layer is coated on the topcoat layer on the outer surface of the skirt of the vehicle body.
8. The coating structure according to claim 7, characterized in that: The protective layer includes an anti-corrosion coating and an impact-resistant layer.
9. The coating structure according to claim 7, characterized in that: The topcoat layer comprises: a topcoat base layer; The varnish layer is applied on the polished surface of the topcoat base layer.
10. The coating structure according to claim 7, characterized in that: The surface energy of the hydrophobic layer is no more than 40 mN / m, and the contact angle of the hydrophobic layer is no less than 130°.