A method for repairing a local defect of a 2K automotive matt paint

Abstract

The application discloses a kind of automobile 2K matt paint local repair methods, it is related to automobile paint surface repair technical field, first to the body defect is checked, polishing, then the body and personnel are blown and cleaned, then shield, color paint spraying, color paint baking, after cooling body, matt varnish spraying, varnish baking, unloading shield and polishing treatment are carried out, check state after handing over car.By adjusting the spray gun spraying pressure and fan width, make local repair spraying when spray gun atomization better, spray mist is more delicate, matting powder will not produce accumulation;By multiple spraying makes spraying more uniform, better effect, greatly improve the uniformity and aesthetic of repair effect;In the case where color paint is completely dried, matt varnish spraying is carried out, without using the traditional paint using the mouth of water.Deliver grid method adhesion ≤1 level, gloss 30±10GU of body original paint quality standard, realize the local repair of matt paint, improve production efficiency, solve the problem of color difference, gloss inconsistency and low efficiency after local repair in the prior art.

Description

Technical Field

[0001] This invention relates to the field of automotive paint repair technology, specifically to a method for local repair of 2K matte paint on automobiles. Background Technology

[0002] Matte paint, also known as "smooth paint," is a type of paint and one of the most widely used coatings in industrial applications. It boasts excellent decorative properties and a soft sheen. The gloss level of matte paint should be below 20-40 GU (at a 60-degree angle). Matte paint films have a more textured feel, and products decorated with this type of paint are highly popular with consumers. Currently, the trend in automotive coatings, especially for electric vehicles, is shifting from high-gloss paints to matte paints, leading to a year-on-year increase in matte paint consumption. The quality and aesthetics of automotive exterior coatings have become a focus for consumers, and the unique matte finish of matte clear coats is favored by many car owners. The ease of mixing and application of 2K matte clear coats makes them popular with many automotive companies.

[0003] In the field of automotive paint repair, localized repair of car surfaces is a common but complex task. Existing traditional methods for repairing high-gloss paint involve sanding, applying color paint, flash drying, applying clear coat, baking, and then sanding and polishing. For matte paint, once damaged, traditional repair methods often result in significant color differences and inconsistent gloss levels compared to the original paint, affecting the overall aesthetics of the car and user satisfaction. Therefore, full-vehicle or part-wide repainting is typically used, making localized repair impossible and severely impacting repair efficiency. Thus, developing a method for localized repair of 2K matte paint while minimizing color and hue differences during the repair process is particularly important. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by devising a method for partial repair of 2K matte paint on automobiles. First, the defects on the car body are inspected and sanded. Then, the car body and personnel are cleaned by blowing and sweeping. Next, masking and color paint are applied. After the color paint is completely dried, a repair clear coat is prepared and applied. After drying, it is sanded with P8000 sandpaper but not polished, effectively avoiding the problems of color difference and inconsistent gloss in matte paint repair.

[0005] The technical solution adopted to realize the present invention is: a method for local repair of 2K matte paint on automobiles, which includes the following steps:

[0006] 1) Defect inspection and polishing:

[0007] The vehicle body defects are classified into clear coat defects and color coat defects. The wet sandpaper is soaked in advance for ≥30 minutes. P2500~P3000 wet sandpaper is used for clear coat defects and P1500 wet sandpaper is used for color coat defects. The wet sandpaper is used to sand the vehicle body defects, and the sanding area is greater than the defect area. After sanding, the surface is flat and without sanding grooves.

[0008] 2) Clean the vehicle body and operators:

[0009] Use a non-woven cloth to wipe away the dust on the vehicle body surface, and use an air gun to blow away the dust from the vehicle body and the painting personnel.

[0010] 3) Concealment:

[0011] The non-sanding and painting areas of the vehicle body are covered with masking tape, and the masking tape is adhered tightly to the vehicle body without gaps.

[0012] 4) Color paint spraying:

[0013] Adjust the distance between the spray gun and the center point of the vehicle body defect to 15-20cm, adjust the spray gun fan width to 60°, adjust the spray gun air pressure to 8 bar, and aim the spray gun at the center point of the vehicle body defect at 90° and move it horizontally downwards slowly. When spraying, spray lightly until the paint surface is matte. After each spray, blow air with the spray gun for 3 seconds and then continue spraying. Spray the defect area 3-5 times. Each spray of the spray gun covers about 1 / 3 of the area of ​​the previous spray until the defect is completely covered.

[0014] 5) Baking of paint:

[0015] The distance between the vehicle body defect and the baking lamp is 30-50cm. The baking lamp is preheated for 1-3 minutes, the baking lamp temperature is 130±10℃, and the baking time is 8-10 minutes, until the paint is completely dried.

[0016] 6) Cooling the car body:

[0017] Blow the areas with the vehicle body defects into the paint area for 3-5 minutes with an air gun, and then cool the vehicle body.

[0018] 7) Matte clear varnish spraying:

[0019] Adjust the distance between the spray gun and the center point of the vehicle body defect to 15-20cm, adjust the spray gun fan angle to 30°, and adjust the spray gun air pressure to 4 bar. Aim the spray gun at the center point of the vehicle body defect at a 90° angle and move it horizontally downwards slowly. Apply a light spray, aiming for a matte finish. Spray the defect area 3-5 times, ensuring each spray covers approximately 1 / 3 of the previous area until the defect is completely covered. The sanding area should be greater than the clear coat area, which should be greater than the color coat area. The clear coat area should be approximately 20% larger than the color coat area. The sanding area should extend 5-10cm beyond the defect area. The matte clear coat should be prepared in advance and used within 4 hours of preparation.

[0020] 8) Baking of matte varnish:

[0021] The distance between the vehicle body defect and the baking lamp is 30-50cm. The baking lamp is preheated for 1-3 minutes, the baking lamp temperature is 130±10℃, and the baking time is 8-10 minutes, until the matte clear coat is completely dried.

[0022] 9) Remove the shielding:

[0023] Remove the masking paper tape from step 3), spray isopropyl alcohol onto a microfiber cloth, and wipe away the adhesive residue from the paper tape on the car body.

[0024] 10) Polishing:

[0025] Use P8000 sandpaper to sand the areas where the body defect was sprayed with matte clear coat to ensure that the repaired areas have a matte finish.

[0026] 11) Inspection:

[0027] The repaired area of ​​the vehicle body defect is observed from multiple angles using a three-color light to ensure that the color difference and gloss of the repaired area are consistent with the condition of the vehicle body. If the color difference and gloss of the repaired area are inconsistent with the condition of the vehicle body, it is necessary to re-sand and repaint.

[0028] Furthermore, the volume ratio of the matte varnish after mixing is matte varnish: hardener: thinner = 2:1~1.5:1~1.5.

[0029] Furthermore, the matte varnish should be used within 4 hours after preparation.

[0030] Furthermore, the area sanded with wet sandpaper is extended by 5 to 10 cm beyond the area of ​​the vehicle body defect.

[0031] Furthermore, the aforementioned baking lamp is an automotive infrared paint baking lamp.

[0032] Furthermore, the compressed air pressure of the air gun is 6-8 bar.

[0033] The beneficial technical effects of this invention's method for localized repair of automotive 2K matte paint are reflected in the following aspects:

[0034] A method for partial repair of 2K matte paint on automobiles is proposed. This method optimizes the formulation of the matte clear coat used for partial repair spraying, reducing curing time, accelerating solvent evaporation, and achieving a spray finish closer to the car body. The matte clear coat is applied after the base coat is completely dry, eliminating the need for traditional touch-up filler. The clear coat application area is 20% larger than the base coat area but smaller than the sanding area, achieving a cross-cut adhesion rating of ≤1 and a gloss level of 30±10GU, meeting the original car body paint quality standards. Adjusting the spray gun pressure and fan width improves atomization during partial repair spraying, resulting in a finer paint mist and preventing matte powder buildup. Multiple coats ensure more even application and better results, significantly improving the uniformity and aesthetics of the repair. This method achieves partial repair of matte paint, increases production efficiency, and solves the problems of color difference, inconsistent gloss, and low efficiency in existing partial repair techniques. Attached Figure Description

[0035] Figure 1 This is a flowchart of a method for partial repair of 2K matte paint on automobiles;

[0036] Figure 2 This is a diagram showing the spray gun distance and fan width;

[0037] Figure 3 This is a diagram illustrating partial repair of matte paint on automotive parts.

[0038] In the picture: 1. Spray gun, 2. Car parts. Detailed Implementation

[0039] The following is in conjunction with the appendix Figures 1-3 The following detailed description of the embodiments further illustrates the present invention. To make the objectives, technical solutions, and advantages of the embodiments clearer, the technical solutions in the embodiments will be clearly and completely described in conjunction with the present invention. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0040] As attached Figure 1 As shown, a method for partial repair of 2K matte paint on automobiles includes the following steps:

[0041] 1) Defect inspection and polishing:

[0042] The vehicle body defects are classified into clear coat defects and color coat defects. The wet sandpaper is soaked in advance for ≥30 minutes. P2500 to P3000 wet sandpaper is used for clear coat defects and P1500 wet sandpaper is used for color coat defects. The wet sandpaper is used to sand the vehicle body defects. The sanding area of ​​the wet sandpaper is greater than the area of ​​the vehicle body defect. The sanding area of ​​the wet sandpaper extends 5 to 10 cm beyond the area of ​​the vehicle body defect. After sanding, the surface is flat and without sanding grooves.

[0043] 2) Clean the vehicle body and operators:

[0044] Use a non-woven cloth to wipe away the dust on the vehicle body surface, and use an air gun to blow away the dust from the vehicle body and the painting personnel.

[0045] 3) Concealment:

[0046] The non-sanding and painting areas of the vehicle body are covered with masking tape, and the masking tape is adhered tightly to the vehicle body without gaps.

[0047] 4) Paint spraying:

[0048] As attached Figure 2 As shown, adjust the distance between the spray gun and the center point of the vehicle body defect to 15-20cm, adjust the spray gun fan width to 60°, adjust the spray gun air pressure to 8 bar, and aim the spray gun at the center point of the vehicle body defect at 90° and move it horizontally downwards slowly. The spray gun should be used for light spraying, aiming for a matte finish. After each spray, blow air through the spray gun for 3 seconds and then continue spraying. Spray the defective area 3-5 times. Each spray gun should cover about 1 / 3 of the area of ​​the previous spray until the defect is completely covered.

[0049] 5) Baking of paint:

[0050] The distance between the vehicle body defect and the baking lamp is 30-50cm. The baking lamp is preheated for 1-3 minutes, the baking lamp temperature is 130±10℃, and the baking time is 8-10 minutes, until the paint is completely dried.

[0051] 6) Cooling the car body:

[0052] Blow the areas with the vehicle body defects into the paint area for 3-5 minutes with an air gun, and then cool the vehicle body.

[0053] 7) Matte clear varnish spraying:

[0054] The volume ratio of the prepared matte clear coat is matte clear coat: hardener: thinner = 2:1~1.5:1~1.5. Adjust the distance of the spray gun from the center point of the vehicle body defect to 15~20cm, adjust the spray gun fan angle to 30°, and adjust the spray gun air pressure to 4 bar. Position the spray gun at a 90° angle to the center point of the vehicle body defect and move it horizontally downwards slowly. Apply the spray gun lightly, aiming for a matte finish. Spray the defect area 3~5 times. Each spray gun application should cover approximately 1 / 3 of the area covered in the previous application until the defect is completely covered. The sanding area > clear coat area > color coat area. The clear coat area is approximately 20% larger than the color coat area. The sanding area should extend 5~10cm beyond the defect area. The matte clear coat should be prepared in advance and used within 4 hours of preparation.

[0055] 8) Baking of matte varnish:

[0056] The distance between the vehicle body defect and the baking lamp is 30-50cm. The baking lamp is preheated for 1-3 minutes, the baking lamp temperature is 130±10℃, and the baking time is 8-10 minutes, until the matte clear coat is completely dried.

[0057] 9) Remove the shielding:

[0058] Remove the masking paper tape from step 3), spray isopropyl alcohol onto a microfiber cloth, and wipe away the adhesive residue from the paper tape on the car body.

[0059] 10) Polishing:

[0060] Use P8000 sandpaper to sand the areas where the body defect was sprayed with matte clear coat to ensure that the repaired areas have a matte finish.

[0061] 11) Inspection:

[0062] The repaired area of ​​the vehicle body defect is observed from multiple angles using a three-color light to ensure that the color difference and gloss of the repaired area are consistent with the condition of the vehicle body. If the color difference and gloss of the repaired area are inconsistent with the condition of the vehicle body, it is necessary to re-sand and repaint.

[0063] Example:

[0064] As attached Figure 3 As shown, for partial repair of automotive matte paint, the mixing ratio of matte clear varnish for partial repair spraying has been optimized and adjusted. The volume ratio of the matte clear varnish after mixing is matte clear varnish: hardener: thinner = 2:1~1.5:1~1.5, which reduces curing time, allows solvent to evaporate faster, and results in a sprayed finish that more closely resembles the car body. (See attached image.) Figure 2As shown, by adjusting the spraying pressure and fan width of spray gun 1, the atomization of the spray gun is better during local repair spraying, the sprayed paint mist is finer, and the matte powder will not accumulate. Multiple sprays make the spraying more uniform and the effect better. The matte clear coat is sprayed after the color paint is completely dry, and there is no need to use the joint filler used in traditional touch-up paint. The clear coat spraying area is 20% larger than the color paint area and smaller than the sanding area, achieving the original paint quality standard of car body with cross-cut adhesion ≤1 level (GB / T 9286-2021) and gloss 30±10GU (60-degree angle). P8000 sandpaper is used for sanding, and no polishing is required to ensure the matte state of the car body repair area.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for localized repair of 2K matte paint on automobiles, characterized in that, It includes the following steps: 1) Defect inspection and polishing: The vehicle body defects are classified into clear coat defects and color coat defects. The wet sandpaper is soaked in advance for ≥30 minutes. P2500~P3000 wet sandpaper is used for clear coat defects and P1500 wet sandpaper is used for color coat defects. The wet sandpaper is used to sand the vehicle body defects, and the sanding area is greater than the defect area. After sanding, the surface is flat and without sanding grooves. 2) Clean the vehicle body and operators: Use a non-woven cloth to wipe the dust off the car body surface, and use an air gun to blow away the dust off the car body and the painting personnel. 3) Concealment: The non-sanding and painting areas of the vehicle body are covered with masking tape, and the masking tape is adhered tightly to the vehicle body without gaps. 4) Paint spraying: Adjust the distance between the spray gun and the center point of the vehicle body defect to 15-20cm, adjust the spray gun fan width to 60°, adjust the spray gun air pressure to 8 bar, and aim the spray gun at the center point of the vehicle body defect at 90° and move it horizontally downwards slowly. When spraying, spray lightly until the paint surface is matte. After each spray, blow air with the spray gun for 3 seconds and then continue spraying. Spray the defective area of ​​the vehicle body 3-5 times. Each spray area should cover 1 / 3 of the area of ​​the previous spray until the defect is completely covered. 5) Baking of paint: The distance between the vehicle body defect and the baking lamp is 30-50cm. The baking lamp is preheated for 1-3 minutes, the baking lamp temperature is 130±10℃, and the baking time is 8-10 minutes, until the paint is completely dried. 6) Cooling the car body: Blow the areas with the described car body defects with an air gun for 3-5 minutes to cool the car body; 7) Matte clear varnish spraying: Adjust the distance between the spray gun and the center point of the vehicle body defect to 15-20cm, adjust the spray gun fan angle to 30°, and adjust the spray gun air pressure to 4 bar. Aim the spray gun at the center point of the vehicle body defect at a 90° angle and move it horizontally downwards slowly. Apply a light spray, aiming for a matte finish. Spray the defect area 3-5 times, ensuring each spray covers 1 / 3 of the previous area until the defect is completely covered. The area to be sanded should be greater than the area to be coated with matte clear coat, which should be greater than the area to be coated with color paint. The area to be coated with matte clear coat should be 20% greater than the area to be coated with color paint. The matte clear coat should be prepared in advance and used within 4 hours of preparation. 8) Baking of matte varnish: The distance between the vehicle body defect and the baking lamp is 30-50cm. The baking lamp is preheated for 1-3 minutes, the baking lamp temperature is 130±10℃, and the baking time is 8-10 minutes, until the matte clear coat is completely dried. 9) Remove the shielding: Remove the masking paper tape from step 3), spray isopropyl alcohol onto a microfiber cloth, and wipe away the adhesive residue from the paper tape on the car body. 10) Polishing: Use P8000 sandpaper to sand the areas where the body defect was sprayed with matte clear coat to ensure that the repaired areas have a matte finish. 11) Inspection: The repaired area of ​​the vehicle body defect is observed from multiple angles using a three-color light to ensure that the color difference and gloss of the repaired area are consistent with the condition of the vehicle body. If the color difference and gloss of the repaired area are inconsistent with the condition of the vehicle body, it is necessary to re-sand and repaint.

2. The method for local repair of 2K matte paint on automobiles according to claim 1, characterized in that, The volume ratio of the prepared matte varnish is matte varnish: hardener: thinner = 2:1~1.5:1~1.

5.

3. The method for local repair of 2K matte paint on automobiles according to claim 1, characterized in that, The area sanded with wet sandpaper is 5-10cm larger than the defect area on the car body.

4. The method for local repair of 2K matte paint on automobiles according to claim 1, characterized in that, The aforementioned The heating lamp is an infrared paint heating lamp for automobiles.

5. The method for local repair of 2K matte paint on automobiles according to claim 1, characterized in that, The compressed air pressure of the air gun is 6-8 bar.

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