Multi-color coating process for automobile door handle

Abstract

The invention discloses an automobile door handle multicolor coating process which comprises the following steps: S1, spraying primer on an automobile door handle, and drying; s2, water-based paint is sprayed on the primer, and drying is conducted; s3, cutting the paint layer along the edge seam by using cutting equipment, and tearing and stripping any side of the coating; s4, intermediate paint is sprayed on the whole automobile door handle and dried; s5, stripping the water-based paint and the intermediate paint on the other side of the automobile door handle from the primer; s6, finish paint is sprayed on the whole automobile door handle; the water-based paint in the step S2 is prepared from the following components in parts by weight: 90 to 95 parts of water-based polyurethane resin, 5 to 10 parts of water-based additive and 2 to 5 parts of chain extender. Under the condition that the water-based paint is arranged between the primer layer and the intermediate paint layer, the water-based paint and the primer layer can be well stripped, so that the adhesive force and the peelability are moderate, and a good intermediate conversion effect is achieved; after the water-based paint layer is stripped, the paint layers with tidy and attractive middle boundary lines of the adjacent two colors are firmly engaged.

Description

Technical Field

[0001] The invention relates to an automobile spraying process, and in particular to a multi-color painting process for automobile door handles. Background Art

[0002] After pretreatment and spraying a basecoat, automotive door handles require an intermediate coat to meet varying stripe requirements. This creates a stripe effect with various colors. To separate the two paint layers, a layer of water-based paint is often added between them. For example, Application No. 201721808097.4 discloses a water-based peelable coating structure for automotive applications. A modified water-based polyurethane primer is sprayed onto the surface of the original paint layer, facilitating full-sheet peeling and touch-up. While this modified water-based paint layer is suitable for single-layer touch-up, it exhibits poor mechanical properties, resulting in jagged edges when cut. It is therefore only suitable for full-sheet peeling and is unsuitable for mass production. Furthermore, in the automotive plastic parts spray coating industry, strippable water-based paints typically achieve moderate adhesion and strippability after reacting with a single paint finish, meeting mass production requirements. However, achieving moderate adhesion and strippability after reacting with multiple paint finishes is difficult. Summary of the Invention

[0003] An object of the present invention is to provide a multi-color painting process for automobile door handles that can solve at least one of the above-mentioned problems.

[0004] According to one aspect of the present invention, a multi-color painting process for automobile door handles is provided, comprising the following steps: S1. Spray primer on the car door handle and dry it; S2. Spray water-based paint on the primer and dry it; S3. Use a cutting device to cut the paint layer along the edge seam and tear off any side of the peeling coating; S4. Spray the intermediate paint on the entire car door handle and dry it; S5. Peel off the remaining water-based paint, intermediate paint and primer on the other side of the car door handle; S6. Spray topcoat on the entire car door handle; The water-based paint in S2 is composed of the following components in parts by weight: 90-95 parts of waterborne polyurethane resin, 5-10 parts of waterborne additive and 2-5 parts of chain extender.

[0005] In some embodiments, the coating layer formed by the water-based paint in S2 has a thickness of 100-120 μm.

[0006] In some embodiments, the chain extender is 3,3'-diethyl-4,4'-diaminodiphenylmethane.

[0007] In some embodiments, the primer includes the following components in parts by weight: 65-75 parts of hydroxy acrylic resin, 10-20 parts of pigment, 1-5 parts of matting powder and 10-15 parts of butyl acetate.

[0008] In some embodiments, the intermediate paint includes the following components in parts by weight: 60-70 parts of hydroxy acrylic resin, 5-10 parts of aluminum paste, 5-10 parts of ethyl acetate, 15-20 parts of butyl acetate and 10-20 parts of pigment.

[0009] In some embodiments, the coating layer formed by the primer has a thickness of 10 to 15 μm, and the coating layer formed by the intermediate paint has a thickness of 8 to 10 μm.

[0010] The beneficial effects of the present invention are: By adopting the water-based paint of the present invention, the water-based paint can be well peeled off from the primer and the intermediate paint when the water-based paint is between the primer and the intermediate paint, so that the adhesion and peelability are moderate, and a good intermediate conversion effect is achieved; after the water-based paint layer is peeled off, the intermediate boundary line of the adjacent two colors is neat and beautiful, and the bite between the paint layers is firm; The water-based paint of the present invention can meet the batch manufacturing requirements of the multi-color coating process for automobile door handles. After the water-based paint layer is cut by a cutting device, it can be separated by mechanical equipment and has good strippability. By adopting the above steps, the accuracy of the boundary line of the two-color transition zone of the spraying is ensured, and the boundary color mixing, blurring and shadowing that are easily caused by traditional spraying processes such as masking spraying are avoided, thereby improving the stability of batch production of coatings and reducing spraying defects. At the same time, it solves the quality defect of unclear masking areas formed by masking with plastic fixtures in the existing technology; By adopting the formula components of the above-mentioned paint layers, it can be suitable for mass production of automotive parts and suitable for automated spraying, so that the thickness of the formed paint film is stable and the surface of the paint film is uniform, which has a good protective effect on the original paint surface. After the water-based paint layer is removed, the protected paint surface retains a good paint effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a rendering of the state in which the water-based paint is peeled off from the primer in step S3 of the multi-color coating process for automobile door handles of the present invention.

[0012] Figure 2 This is a rendering of the state in which the water-based paint and the intermediate paint are peeled off from the primer in step S5 of the multi-color painting process for automobile door handles of the present invention. DETAILED DESCRIPTION

[0013] The present invention will be further described in detail below with reference to the accompanying drawings.

[0014] Example 1

[0015] A multi-color coating process for automobile door handles of the present invention comprises the following steps: S1. Spray primer on the car door handle and dry it; S2. Spray water-based paint on the primer and dry it; S3. Use cutting equipment to cut the paint layer along the seam and tear off any side of the peeling coating (such as Figure 1 shown); S4. Spray the intermediate paint on the entire car door handle and dry it; S5. Peel off the remaining water-based paint, intermediate paint and primer on the other side of the car door handle (such as Figure 2 shown); S6. Spraying a topcoat on the entire automobile door handle, wherein the topcoat can be an existing topcoat or varnish commonly sprayed on automobile door handles, which plays a protective role and improves the glossiness of the entire paint layer.

[0016] The primer in step S1, the water-based paint in step S2, the intermediate paint in step S4, and the topcoat in step S6 can all be automatically sprayed using spraying equipment, which facilitates the mass production of automobile door handles. The paint film thickness in each step is stable and the paint film surface is uniform.

[0017] The water-based paint in S2 is composed of the following components in parts by weight: 925 parts of waterborne polyurethane resin, 8 parts of waterborne additive, and 3 parts of chain extender. The CAS No. of the waterborne polyurethane resin is 9009-54-5, and the waterborne additive is 2,2,4-trimethylpentanediol monoisobutyrate, CAS No. 77-68-9.

[0018] The coating thickness formed by the water-based paint in step S2 is 100-120 μm.

[0019] The chain extender is 3,3'-diethyl-4,4'-diaminodiphenylmethane, and the CAS No. of the chain extender is 19900-65-3.

[0020] Therefore, the present invention adopts the water-based paint. After the water-based paint is sprayed on the primer to form a film, when performing step S3, the water-based paint layer can be cut by using a cutting device. During cutting, arbitrary cutting can be achieved without dropping debris, and the edges are neat and non-serrated. The formed edges are clear, which makes it convenient to manually or mechanically peel off any side after cutting. During peeling, the primer is not affected, and the peeling performance is excellent.

[0021] During the existing batch painting, a shielding spray fixture is used to shield the side that does not need to be sprayed with the corresponding intermediate paint. After spraying, the shielding spray fixture needs to be repeatedly cleaned and inspected to avoid color interference. In addition, the shielding spray fixture has high production costs, long working hours, and large losses during use. The clamping accuracy requirements of the shielding spray fixture are high, which easily produces defective products and increases the cost of mass production.

[0022] By using this water-based paint and the aforementioned process steps, the present invention allows the entire door handle to be sprayed without shielding during the application of the intermediate coat, significantly improving production efficiency, making it suitable for mass production, and significantly reducing production costs. A comparison of the specific production efficiencies of the existing spraying process using a shielding fixture and the present invention can be found in the table below: Process Type Production efficiency (pieces / hour) Number of employees (number of people) yield Traditional spraying process 300 10 80% Coating process of the present invention 2800 15 95% It can be seen that the production efficiency and yield rate are greatly improved when the multi-color coating process for automobile door handles of the present invention is sprayed on automobile door handles. The traditional shielding spraying process has low production efficiency, complicated procedures and low yield rate. The shielding spraying fixture needs to be assembled before spraying, and the spraying fixture needs to be disassembled after spraying. The spraying fixture needs to be cleaned before it can be recycled. At the same time, traditional spraying processes such as shielding spraying are prone to causing defects such as boundary color mixing, blurring and shadows. Although the present invention increases the number of workers, it makes the process coherent and improves production efficiency by 900%. At the same time, it improves the stability of batch production of coatings, reduces spraying defects, and solves the quality defects of unclear masking areas of plastic fixtures, such as flying paint, sticky paint and sawtooth defects.

[0023] After the various process steps of the present invention, the primer on the side where the water-based paint layer was stripped after step S3 can be covered with an intermediate paint, thereby forming a color different from the primer. On the side stripped after step S5, the intermediate paint is stripped along with the water-based paint, thus retaining the color of the primer, thereby creating a multi-color coating effect for the automobile door handle. In actual use, automobile door handles or other automobile parts can be sprayed with different colors according to actual needs to meet multi-color spraying requirements.

[0024] The primer comprises the following components in parts by weight: 70 parts of hydroxy acrylic resin, 20 parts of pigment, 3 parts of matting powder and 12 parts of butyl acetate.

[0025] In actual use, the pigment of the primer can be adjusted according to the actual color requirements. For example, when using a black primer, the pigment is composed of nano black paste and nano green paste, which makes the black primer have a good gloss effect. The CAS No. of the nano black paste is 1333-86-4, and the CAS No. of the nano green paste is 1328-53-6; the nano black paste is 15 parts and the nano green paste is 5 parts.

[0026] By adopting this primer, the water-based paint can form a certain adhesion after being sprayed on the primer, and at the same time have corresponding strippability. When the water-based paint layer is peeled off on the primer, the primer will not be peeled off together, thus ensuring the stability of the paint layer.

[0027] The intermediate paint comprises the following components in parts by weight: 65 parts of hydroxy acrylic resin, 8 parts of aluminum paste, 8 parts of ethyl acetate, 18 parts of butyl acetate, and 12 parts of pigment. The pigment can be nano-blue paste, which, when mixed with the aluminum paste, creates a matte titanium silver color effect, meeting the corresponding requirements. Alternatively, it can be a dark night black mid-coat. Specifically, the pigment can be nano-black paste, nano-blue paste, and nano-yellow paste, achieving a dark night black color effect. The nano-black paste is 10 parts, and the nano-blue paste and nano-yellow paste are 1 part each. The CAS No. of nano-blue paste is 57455-37-5, the CAS No. of nano-black paste is 1333-86-4, and the CAS No. of nano-yellow paste is 2783-94-0.

[0028] By adopting this intermediate paint, one side can be well bonded to the primer; at the same time, when the other side is covered on the water-based paint layer, it can be bonded to the water-based paint, making it easy to separate the subsequent water-based paint together with the intermediate paint on this side from the primer on the corresponding side.

[0029] The coating thickness of the primer is 10-15 μm, and the coating thickness of the intermediate paint is 8-10 μm. Therefore, when each paint layer reaches its corresponding thickness, each paint layer has good coverage and mechanical properties, and the water-based paint has corresponding strippability.

[0030] The mechanical properties and strippability of each paint layer obtained by the multi-color coating process for automobile door handles of the present invention are now compared with those of conventional water-based paint, as shown in the following table: project Corresponding paint layer combination Mechanical properties Peelability The paint layer of the present invention Water-based paint over primer Can be cut arbitrarily without dropping debris, with neat edges and no jagged edges Can be peeled manually or mechanically Existing spray paint layer Water-based paint over primer The edge is jagged after cutting The yield rate of manual stripping is less than 70%, and mechanical stripping is not possible. The paint layer of the present invention Intermediate paint covers the water-based paint Can be cut arbitrarily without dropping debris, with neat edges and no jagged edges Can be peeled manually or mechanically Existing spray paint layer Intermediate paint covers the water-based paint The edge is jagged after cutting and there are chips The yield rate of manual stripping is less than 50%, and mechanical stripping is not possible. It can be seen from this that the various coatings in the multi-color coating process for automobile door handles of the present invention are suitable for mass production of automobile parts and automated spraying. The paint film formed has a stable thickness and a uniform surface, has a good protective effect on the original paint surface, and has excellent mechanical properties and strippability.

[0031] Example 2 The multi-color coating process for a car door handle in this embodiment is basically the same as that in the embodiment, and the effect achieved is also the same. The difference is that: The water-based paint in S2 is composed of the following components in parts by weight: 90 parts of waterborne polyurethane resin, 5 parts of waterborne additive and 2 parts of chain extender.

[0032] The primer comprises the following components in parts by weight: 65 parts of hydroxy acrylic resin, 15 parts of pigment, 1 part of matting powder and 10 parts of butyl acetate; among the pigments, 12 parts of nano black paste and 3 parts of nano green paste.

[0033] The intermediate paint comprises the following components in parts by weight: 60 parts of hydroxy acrylic resin, 5 parts of aluminum silver paste, 5 parts of ethyl acetate, 15 parts of butyl acetate and 10 parts of pigment; the pigment can be nano black paste, nano blue paste and nano yellow paste to achieve a dark night black color effect, with 8 parts of nano black paste, 1 part of nano blue paste and 1 part of nano yellow paste.

[0034] Example 3 The multi-color coating process for a car door handle in this embodiment is basically the same as that in the embodiment, and the effect achieved is also the same. The difference is that: The water-based paint in S2 is composed of the following components in parts by weight: 95 parts of waterborne polyurethane resin, 10 parts of waterborne additive and 5 parts of chain extender.

[0035] The primer comprises the following components in parts by weight: 75 parts of hydroxy acrylic resin, 10 parts of pigment, 5 parts of matting powder and 15 parts of butyl acetate; among the pigments, 8 parts of nano black paste and 2 parts of nano green paste.

[0036] The intermediate paint comprises the following components in parts by weight: 70 parts of hydroxy acrylic resin, 10 parts of aluminum silver paste, 10 parts of ethyl acetate, 20 parts of butyl acetate and 20 parts of pigment; the pigment can be nano black paste, nano blue paste and nano yellow paste to achieve a dark night black color effect, nano black paste is 12 parts, nano blue paste and nano yellow paste are 4 parts each.

[0037] The above are only preferred embodiments of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A multi-color coating process for automobile door handles, characterized in that: The steps include: S1. Spray primer on the car door handle and dry it; S2. Spray water-based paint on the primer and dry it; S3. Use a cutting device to cut the paint layer along the edge seam and tear off any side of the peeling coating; S4. Spray the intermediate paint on the entire car door handle and dry it; S5. Peel off the remaining water-based paint, intermediate paint and primer on the other side of the car door handle; S6. Spray topcoat on the entire car door handle; The water-based paint in S2 is composed of the following components in parts by weight: 90-95 parts of waterborne polyurethane resin, 5-10 parts of waterborne additive and 2-5 parts of chain extender.

2. The multi-color coating process for automobile door handles according to claim 1, characterized in that: The coating thickness formed by the water-based paint in S2 is 100-120 μm.

3. The multi-color coating process for automobile door handles according to claim 2, characterized in that: The chain extender is 3,3'-diethyl-4,4'-diaminodiphenylmethane.

4. A multi-color coating process for automobile door handles according to any one of claims 1 to 3, characterized in that: The primer comprises the following components in parts by weight: 65-75 parts of hydroxy acrylic resin, 10-20 parts of pigment, 1-5 parts of matting powder and 10-15 parts of butyl acetate.

5. The multi-color coating process for automobile door handles according to claim 4, characterized in that: The intermediate paint comprises the following components in parts by weight: 60-70 parts of hydroxy acrylic resin, 5-10 parts of aluminum paste, 5-10 parts of ethyl acetate, 15-20 parts of butyl acetate and 10-20 parts of pigment.

6. The multi-color coating process for automobile door handles according to claim 2, characterized in that: The coating layer formed by the primer has a thickness of 10 to 15 μm, and the coating layer formed by the intermediate paint has a thickness of 8 to 10 μm.

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