Coating method of exterior trimming part and exterior trimming part

Abstract

The invention relates to a coating method of an exterior trimming part and the exterior trimming part, the coating method is applied to a coating line, printing equipment is arranged on the coating line, the coating method comprises the steps that the exterior trimming part is placed on the coating line, and a prefabricated pattern is printed on the surface of the exterior trimming part through the printing equipment to form a printing pattern layer; spraying primer on the printed pattern layer on the surface of the exterior trimming part to form a primer layer; colored paint is sprayed on the primer layer on the surface of the exterior trimming part to form a colored paint layer; printing ink of the printing pattern layer penetrates through the primer layer and then is dissolved with a solvent of colored paint, and the prefabricated pattern is shown on the colored paint layer; and spraying varnish on the colored paint layer on the surface of the exterior trimming part to form a varnish layer. According to the coating method of the exterior trimming part and the exterior trimming part, pattern printing and paint spraying are completed at a time on the coating line, the additional process of entering and exiting the coating line does not need to be added, and therefore the production process is simplified, and the percent of pass is increased.

Description

Technical Field

[0001] The present invention relates to the field of coating of vehicle exterior parts, and more particularly to a coating method of an exterior part and the exterior part. Background Art

[0002] As a means of outdoor transportation, the exterior trim of a vehicle will be subject to long-term erosion by various corrosive media in the atmosphere, such as moisture, oxygen, industrial atmosphere, sulfur dioxide, carbon dioxide, nitrogen dioxide, etc. Therefore, the exterior trim is usually painted on a painting line to spray a protective paint (such as spraying three layers of paint including primer, color paint and clear varnish) on its surface to play a role in protection, decoration and identification.

[0003] With the development of the automotive industry, vehicle personalization is becoming increasingly prominent, and the demand for displaying various patterns on vehicle exterior trims is also increasing. To meet this demand for patterns, two common methods are currently used in the art. The first method is to apply a film with a pre-fabricated pattern to the surface of the exterior trim after painting. The second method is to spray primer, color paint, and varnish on the painting line, remove the exterior trim from the painting line, and use a printing device to print the pattern. The exterior trim is then moved back to the painting line and sprayed with one or two layers of clear protective paint to protect the pattern and prevent it from fading or discoloring.

[0004] However, the first method can only be used after the exterior trim is produced, and will fade and discolor after a period of time, resulting in a very poor appearance; the second method requires the exterior trim to go through two painting lines, and one more painting line will cause the product's pass rate to drop exponentially, so its process is complex, the pass rate is low, and the cost is high. Summary of the Invention

[0005] The object of the present invention is to provide a coating method and exterior trim, which can complete pattern printing and painting at one time on a coating line without adding additional processes of entering and exiting the coating line, thereby simplifying the production process and improving the qualification rate.

[0006] Based on the above objectives, the present invention provides, on one hand, a coating method for exterior parts, wherein the coating method is applied to a coating line provided with a printing device, and the coating method comprises:

[0007] Placing the exterior trim on a coating line, and using the printing device to print a prefabricated pattern on the surface of the exterior trim to form a printed pattern layer;

[0008] spraying a primer on the printed pattern layer on the surface of the exterior trim to form a primer layer;

[0009] spraying a color paint on the primer layer on the surface of the exterior part to form a color paint layer; the ink of the printed pattern layer penetrates the primer layer and dissolves with the solvent of the color paint, thereby showing the prefabricated pattern on the color paint layer;

[0010] The clear varnish is sprayed on the color paint layer on the surface of the exterior trim to form a clear varnish layer.

[0011] Furthermore, the printing device is a thermal transfer device, a screen printing device or a pad printing device.

[0012] Furthermore, before printing the prefabricated pattern on the surface of the exterior trim using the printing device, the method further includes:

[0013] The exterior trim is degreased.

[0014] Furthermore, before spraying the primer on the printed pattern layer on the surface of the exterior trim, the method further includes:

[0015] The exterior parts are sequentially subjected to water washing and flame treatment.

[0016] Furthermore, before spraying the color paint on the primer layer on the surface of the exterior trim, the method further comprises:

[0017] The primer on the surface of the exterior trim is flash-dried.

[0018] Furthermore, before spraying the varnish on the color paint layer on the surface of the exterior trim, the method further comprises:

[0019] Flash-drying the paint on the surface of the exterior trim.

[0020] Furthermore, it also includes:

[0021] The varnish on the surface of the exterior decoration part is dried to solidify the varnish into a shape.

[0022] Furthermore, it also includes:

[0023] The exterior trim is removed from the coating line, and the quality of the exterior trim is inspected to determine whether the exterior trim is qualified.

[0024] Furthermore, the painting line is an automated painting line based on robots.

[0025] Another aspect of the present invention provides an exterior trim, wherein a printed pattern layer, a primer layer, a color paint layer and a varnish layer are sequentially provided on the surface of the exterior trim, and the exterior trim is obtained by the exterior trim coating method described above.

[0026] The coating method and exterior trim of the present invention are characterized in that a printing device is provided on a coating line, and a prefabricated pattern is printed on the surface of the exterior trim using the printing device, and then a primer, a color paint and a clear coat are sprayed in sequence. Since the ink of the prefabricated pattern can penetrate the solvents of the primer and the color paint and mutually dissolve, the prefabricated pattern can be revealed in the color paint layer, thereby completing the pattern printing and painting at one time on the coating line without adding additional processes of entering and exiting the coating line, which can simplify the production process and improve the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of a coating method for an exterior trim according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the structure of an exterior trim after painting according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0030] like Figure 1 As shown, an embodiment of the present invention provides a coating method for exterior parts, which is applied to a coating line provided with a printing device, and includes the following steps:

[0031] S100: placing the exterior trim on a coating line, and using a printing device to print a prefabricated pattern on the surface of the exterior trim to form a printed pattern layer;

[0032] In some embodiments, the printing device can be a thermal transfer device (i.e., UV printing device), a screen printing device, a pad printing device, or any other suitable device, which can print a prefabricated pattern on the varnish layer by UV printing, screen printing, or pad printing. Among them, UV printing uses UV (ultraviolet) or near-ultraviolet light as an irradiation source to transfer the image and text to the medium. Screen printing refers to using a silk screen as a base and using a photosensitive platemaking method to make a screen printing plate with images and text. During printing, ink is poured into one end of the screen printing plate, and a scraper is used to apply a certain pressure to the ink area on the screen printing plate. At the same time, it moves at a constant speed toward the other end of the screen printing plate. During movement, the ink is squeezed from the mesh of the image and text part by the scraper onto the substrate. Pad printing uses a steel (or copper, thermoplastic plastic, etc.) gravure and a curved pad printing head made of silicone rubber material. The ink on the gravure is dipped onto the surface of the pad printing head, and then the gravure is pressed against the surface of the medium to print the pattern on the medium surface.

[0033] In some embodiments, the prefabricated patterns can be customized as needed to meet the individual needs of customers.

[0034] In some embodiments, the coating line can be modified from an existing coating line. Specifically, a printing device can be installed before the primer station (i.e., the primer booth) of the existing coating line. In other words, the coating line of the present invention differs from existing coating lines only in that a printing device is added before the basecoat station, allowing the printing device to print a prefabricated pattern on the surface of the exterior trim before the primer is sprayed.

[0035] In some embodiments, the exterior trim is a plastic part that is integrally formed by injection molding.

[0036] In some embodiments, before printing the prefabricated pattern on the surface of the exterior trim using a printing device, the coating method may further include:

[0037] Degreasing exterior trim removes grease and improves paint adhesion and corrosion resistance. Specifically, the exterior trim is immersed in a tank of lye for a period of time before being removed to remove the grease. Degreasing can be performed at the degreasing station on the coating line.

[0038] S200: spraying a primer on the printed pattern layer on the surface of the exterior trim to form a primer layer;

[0039] Primer is the first layer of a paint system, used to improve the adhesion of the basecoat, increase the fullness of the basecoat, provide alkali resistance, and provide corrosion protection. It also ensures uniform absorption of the basecoat, allowing the paint system to perform optimally. In some embodiments, spraying the primer can be completed in the primer station (i.e., primer room) of the paint line.

[0040] In some embodiments, before spraying the primer on the surface of the exterior trim, the coating method may further include:

[0041] Exterior trims are sequentially water-washed and flame-treated. Water-washing cleans the surface of exterior trims, preventing debris (such as dust) from affecting the paint finish. Flame-treating involves subjecting the exterior trim to high-temperature flames, which alters the microstructure of the surface and increases surface roughness, thereby enhancing paint adhesion. Water-washing can be performed using dedicated water-washing equipment at the coating line's water-washing station, while flame-treating can be performed using dedicated flame-treating equipment at the coating line's flame-treating station.

[0042] S300: spraying color paint on the primer layer on the surface of the exterior part to form a color paint layer; the ink of the printed pattern layer penetrates the primer layer and dissolves with the solvent of the color paint, thereby showing a prefabricated pattern on the color paint layer;

[0043] Colored paint is a coating made by adding various pigments and flavorings to a paint to impart color to the coating film, block light transmission, or enhance the coating film's mechanical and chemical properties. When applied to a substrate, the resulting coating film can cover the substrate and provide protective, decorative, or special technical properties. In some embodiments, the color of the colored paint can be customized as needed, serving as a vehicle logo and enhancing the vehicle's appearance. In some embodiments, spraying the colored paint can be completed in a colored paint station (i.e., a colored paint room) on the coating line.

[0044] The prefabricated pattern is printed on the surface of the exterior part using ink, which is composed of a binder (resin), pigment, filler, additives and solvent. When primer and color paint are sprayed on the ink, the ink will penetrate the primer layer to the color paint layer, and the pigment of the ink will dissolve with the solvent of the color paint, so the prefabricated pattern can be revealed in the color paint layer. In other words, the prefabricated pattern will be transferred from the printed pattern layer to the color paint layer, so the color paint layer can also be called the visible pattern layer, and the above process can be called color migration.

[0045] The main principle of color migration is dissolving power, and the dissolving process is relatively unstable, which is related to the color of the paint and the construction process (such as thickness, construction solvent ratio, etc.). Therefore, the color hue, color depth, etc. of the exterior parts obtained each time the painting is done may be different.

[0046] In some embodiments, before step S300, the coating method may further include:

[0047] Flash the primer on exterior trim surfaces.

[0048] Flash drying refers to the process of allowing solvent-based coatings to sit for a certain period of time during application, allowing the solvent in the paint film to evaporate to a semi-dry state. Flash drying allows the volatile components in the coating to evaporate evenly, while the micro-flow of the solvent creates a smooth, full-bodied finish, preventing defects such as blistering, pinholes, clouding, sagging, deformation, orange peel, and cracking.

[0049] S400: spraying clear varnish on the color paint layer on the surface of the exterior trim to form a clear varnish layer.

[0050] Clearcoat is a coating composed primarily of a resin and a solvent. Both the coating and the film are transparent. After being applied to the basecoat and drying, the clearcoat forms a transparent, smooth film that reveals the prefabricated pattern and the basecoat's color. This protects the pattern without detracting from the exterior's appearance. In some embodiments, spraying the clearcoat can be performed in a clearcoat station (i.e., a clearcoat room) on the coating line.

[0051] Since pigments have poor sun resistance, even if the outermost layer of exterior parts is sprayed with sun-resistant varnish, the color of the pigment may gradually disappear. Therefore, pigments for inks and paints can be selected with better sun resistance.

[0052] In some embodiments, before step S400, the coating method may further include:

[0053] Flash dry the paint on the surface of the exterior parts.

[0054] In some embodiments, after step S400, the coating method may further include:

[0055] The varnish on the surface of the exterior parts is dried to solidify it into shape.

[0056] like Figure 2 As shown, after painting, the surface of the exterior trim 10 is formed, from the inside out, with a printed pattern layer 20, a primer layer 30, a color paint layer 40, and a clear coat layer 50. The ink in the printed pattern layer 20 passes through the primer layer 30 and dissolves with the paint solvent in the color paint layer 40, revealing the prefabricated pattern in the color paint layer 40. This gives the exterior trim 10 the desired color and pattern, meeting the desired appearance. The clear coat layer 50 also protects the color paint layer 40. Because the printed pattern layer 20 is applied to the exterior trim 10 using printing equipment integrated into the painting line, painting and pattern printing can be completed simultaneously on the painting line, eliminating the need for additional entry and exit processes. This simplifies the production process and improves product quality.

[0057] In some embodiments, after step S400, the coating method may further include:

[0058] Remove the exterior trim from the painting line and inspect its quality to determine whether it is qualified.

[0059] In some embodiments, the quality of exterior trim can be tested according to national standards or enterprise standards to determine whether the exterior trim is qualified. If qualified, it can enter the next production process (such as final assembly). If unqualified, it needs to be modified or discarded.

[0060] In some embodiments, the painting line can be a robot-based automated painting line, that is, after the exterior parts are placed on the loading station of the painting line, the painting line will automatically complete the processes of printing prefabricated patterns, washing, flame treatment, spraying primer, flash drying, spraying color paint, flash drying, spraying varnish, drying and unloading, thereby realizing automated painting and improving production efficiency.

[0061] The coating method of exterior trim parts in an embodiment of the present invention is to set up a printing device on the coating line, use the printing device to print a prefabricated pattern on the surface of the exterior trim part, and then spray primer, color paint and varnish in sequence. Since the ink of the prefabricated pattern can penetrate the solvents of the primer and color paint and dissolve each other, the prefabricated pattern can be revealed in the color paint layer, thereby completing pattern printing and painting at one time on the coating line without adding additional processes for entering and exiting the coating line, which can simplify the production process and improve the product qualification rate.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Various modifications are possible. In other words, any simple, equivalent changes and modifications made in accordance with the claims and description of the present invention are within the scope of protection of the patent claims. Anything not fully described in this invention constitutes conventional technology.

Claims

1. A coating method for exterior parts, characterized in that: The coating method is applied to a coating line provided with a printing device, and the coating method comprises: Placing the exterior trim on a coating line, and using the printing device to print a prefabricated pattern on the surface of the exterior trim to form a printed pattern layer; spraying a primer on the printed pattern layer on the surface of the exterior trim to form a primer layer; spraying a color paint on the primer layer on the surface of the exterior part to form a color paint layer; the ink of the printed pattern layer penetrates the primer layer and dissolves with the solvent of the color paint, thereby showing the prefabricated pattern on the color paint layer; The clear varnish is sprayed on the color paint layer on the surface of the exterior trim to form a clear varnish layer.

2. The coating method for exterior parts according to claim 1, characterized in that: The printing device is a thermal transfer device, a screen printing device or a pad printing device.

3. The coating method for exterior parts according to claim 2, characterized in that: Before printing the prefabricated pattern on the surface of the exterior trim using the printing device, the method further includes: The exterior trim is degreased.

4. The coating method for exterior parts according to claim 1, characterized in that: Before spraying the primer on the printed pattern layer on the surface of the exterior trim, it also includes: The exterior parts are sequentially subjected to water washing and flame treatment.

5. The coating method for exterior parts according to claim 1, characterized in that: Before spraying the color paint on the primer layer on the surface of the exterior trim, the method further includes: The primer on the surface of the exterior trim is flash-dried.

6. The coating method for exterior parts according to claim 1, characterized in that: Before spraying clear varnish on the color paint layer on the surface of the exterior trim, the method further comprises: Flash-drying the paint on the surface of the exterior trim.

7. The coating method for exterior parts according to claim 1, characterized in that: Also includes: The varnish on the surface of the exterior decoration part is dried to solidify the varnish into a shape.

8. The coating method for exterior parts according to claim 1, characterized in that: Also includes: The exterior trim is removed from the coating line, and the quality of the exterior trim is inspected to determine whether the exterior trim is qualified.

9. The coating method for exterior parts according to claim 1, characterized in that: The coating line is an automated coating line based on robots.

10. An exterior trim, characterized in that: The surface of the exterior trim is provided with a printed pattern layer, a primer layer, a color paint layer and a varnish layer in sequence, and the exterior trim is obtained by the coating method for exterior trim according to any one of claims 1 to 9.

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