Spraying process for satin face

Abstract

The invention discloses a satin face spraying process which sequentially comprises the steps of automobile body electrophoresis, automobile body floating coat spraying, automobile body colored paint spraying and forming of a spraying layer on the surface of an automobile body, the spraying layer is formed by coating spraying and curing, and the coating specifically comprises paint, a diluent, a curing agent, varnish and a matte agent. The automobile body coating sequentially comprises a metal layer, an electrophoresis layer, a middle coating layer, a colored paint layer, a varnish layer and a matte varnish layer on the surface of an automobile body, through the double-layer varnish spraying and full-matte coating process, the automobile body coating is soft in gloss, high in hazy feeling and high in diffuse reflection rate, the satin face imitating spraying effect is achieved, the automobile paint texture of the whole automobile is improved, and the service life of the automobile is prolonged. And the defects of a conventional spraying process are overcome, and the good market prospect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile body spraying, relates to an automobile body spraying process, and specifically relates to a satin spraying process. Background Art

[0002] With the development of automobile painting technology, users have higher and higher requirements for automobile appearance. Satin painting process is a processing method in automobile painting process, which can achieve a silky satin effect of various colors of paint on the surface of the car body, presenting a new installation, beautification and other effects; therefore, satin-painted cars are increasingly attracting consumers' attention with the beautiful appearance of satin paint film, but due to its complex production process, low production efficiency and high cost, it has always been sold as a special order car.

[0003] At present, there are two types of treatment methods that are closer to the satin coating process: the first type is the single varnish layer semi-matte spraying process, the construction materials include paint materials, pre-treatment agents, electrophoretic paint, intermediate paint, topcoat, diluent, curing agent, varnish, matte agent, the steps of this coating process are divided into: electrophoresis, spray intermediate coating, grinding and degreasing, spraying topcoat, spraying semi-matte varnish, topcoat drying and modification; its advantages are fewer processes, fast speed, and it is a common imitation satin spraying process, but the single varnish semi-matte coating process spraying method has the problems of causing lower pollution, paint penetration, poor visual gloss of the whole vehicle, and unclear satin effect. The second type is the imitation satin color change film pasting process, the construction materials include degreasing agent, dust-sticking cloth, color change film, scraper, the steps of this coating process are divided into: degreasing, dust removal, pasting color change film, modification; the advantages of this method are fewer processes, environmental protection, and many types of color change, but there are disadvantages such as slow speed, poor weather resistance, harsh construction conditions, and difficult to repair damage.

[0004] The above two spraying processes are usually used for low appearance requirements and temporary color change of the car body. The satin effect obtained in this way has a rough and dull appearance, many uneven peaks of different sizes, and poor corrosion resistance. In addition, the spraying process has the disadvantages of high labor intensity, high cost, and serious pollution, which makes it difficult to promote and use it for large-scale vehicle painting in the market. Summary of the invention

[0005] In view of the above problems, the main purpose of the present invention is to design a satin spraying process, which solves the problems of the prior art that the satin spraying process is complex, the production efficiency is low, the cost is high, and it is difficult to apply to large quantities of vehicles through the steps of body electrophoresis, body mid-coat spraying, and body color paint spraying.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions: A satin spraying process is used for body surface modification, which includes body electrophoresis, body mid-coat spraying, and body color paint spraying in sequence; The electrophoretic coating process of the vehicle body includes pretreatment, electrophoretic coating and post-treatment, and the electrophoretic coating is set to three-stage voltage step control; after the electrophoretic paint layer of the vehicle body is dried and solidified, the vehicle body intermediate coating is sprayed; The process of spraying the midcoat on the vehicle body includes pre-spraying treatment, spraying and drying, and post-spraying treatment. The sprayed paint components include midcoat paint, diluent, and curing agent. After the midcoat sprayed paint layer on the vehicle body is completely dry and cured, the vehicle body color paint is sprayed; The process of spraying the car body paint includes preparation before spraying, paint spraying and drying, matte varnish spraying and drying, the paint includes any one of 2K paint, metallic paint, and 1K paint, and the paint, curing agent and diluent are adjusted in proportion for paint spraying.

[0007] As a further description of the present invention, the pretreatment during the electrophoresis process of the vehicle body includes the following steps: S101: Pre-cleaning; The inner and outer surfaces of the car body are sprayed with a high-pressure water gun. The spray pressure of the high-pressure water gun is 60-100 bar, and the water tank temperature of the high-pressure water gun is 30-45℃; S102: degreasing treatment; Through pre-degreasing and degreasing, the car body is immersed in a tank liquid to remove grease and pollution on the surface of the car body; wherein, the pre-degreasing is to immerse the car body in a pre-degreasing tank liquid with a free alkalinity point of 10-18 and a Ph value of 10-13, the tank liquid temperature is 30-45°C, and the immersion time is 278s; the degreasing is to immerse the car body in a degreasing tank liquid with a free alkalinity point of 8-16 and a Ph value of 9-12, the tank liquid temperature is 45-55°C, and the immersion time is 466s; S103: washing; After multiple water washings, the surface of the vehicle body is cleaned; water washing 1 is to immerse the vehicle body in a water washing tank with a Ph value of 7.5-9.5, alkali stains <1.5Pt, conductivity <1000us / cm, and accelerator points of 0.6-2.0Pt, and the immersion time is 248s; water washing 2 is to immerse the vehicle body in a water washing tank with a Ph value of 7.5-9.5, alkali stains <1.5Pt, conductivity <800us / cm, and accelerator points of 0.6-2.0Pt, and the immersion time is 248s.

[0008] As a further description of the present invention, the electrophoretic coating in the electrophoretic coating process of the vehicle body includes the following steps: S111: Surface conditioning and phosphating; The car body is first subjected to surface adjustment and then to phosphating treatment; the surface adjustment is to immerse the car body in a surface adjustment bath with a conductivity of 1400±600μs / cm, a Ph value of 8.5-10, and a Zn point of 10-14, and the immersion time is 238s; the phosphating treatment is to immerse the car body in a phosphating bath with a total acid point of 20-24Pt, a free acid point of 0.8-1.2Pt, and an accelerator point of 1.5-2.5Pt, and the bath temperature during the immersion of the car body is 45-50℃, and the immersion time is 325s; the phosphating film weight of the car body after phosphating treatment is 2.5-4g / m 2 , the phosphating crystal size is 3-10μm; S112: pure water washing; The vehicle body is washed with pure water for multiple times to clean the vehicle body surface; pure water washing 1 is to immerse the vehicle body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <30μs / cm for 244s; pure water washing 2 is to immerse the vehicle body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <30μs / cm for 244s; pure water washing 3 is to immerse the vehicle body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <25μs / cm for 345s; S113: electrophoresis; The vehicle body is immersed in an electrophoretic tank for electrophoretic coating, the total immersion time is 642 seconds, and the coating is uniformly deposited on the surface of the vehicle body through the action of an electric field to form a protective film; the electrophoretic tank is set to have a solid content of 19-23%, a Ph value of 5.6-6.2, an ash content of 15-20%, an MEQ of 25-30, a pigment-to-base ratio of 8-12, a solvent content of 0.6-2.5%, and a tank conductivity of (1100-2000) μs / cm; during the immersion of the vehicle body, the temperature of the electrophoretic tank is maintained at 30-32° C. The electrophoresis is controlled by a three-stage voltage ladder, wherein the first stage voltage is 80-150V and the time is 60-80s, the second stage voltage is 180-240V and the time is 60-120s, and the third stage voltage is 250-290V and the time is 280-340s; the vehicle body is connected to a cathode, and the corresponding anode liquid conductivity is less than 800 μs / cm, and the anode liquid Ph value is 2-6.

[0009] As a further description of the present invention, the post-processing during the electrophoresis process of the vehicle body includes the following steps: S121: ultrafiltration water washing and pure water washing; The surface of the vehicle body is cleaned by multiple ultrafiltration water washing and pure water washing; ultrafiltration water washing 1 is to immerse the vehicle body in ultrafiltration water washing tank liquid, with a solid content of ≤1.1%, a Ph value of 5-6, an ultrafiltration conductivity of 400-1500μs / cm, and an immersion time of 246s; ultrafiltration water washing 2 is to immerse the vehicle body in ultrafiltration water washing tank liquid, with a solid content of ≤0.5%, a Ph value of 5-6, an ultrafiltration conductivity of 400-1200μs / cm, and an immersion time of 246s; Pure water washing 4 is to immerse the vehicle body in a pure water washing tank with a conductivity of less than 150 μs / cm for 245 seconds; pure water washing 5 is to immerse the vehicle body in a pure water washing tank with a conductivity of less than 100 μs / cm for 246 seconds; S122: electrophoresis drying; The paint film of the car body is dried to solidify the electrophoretic paint. The car body temperature during the drying process is 180℃~200℃ and maintained within this temperature range for 25-30min. After drying, the paint film adhesion of the electrophoretic paint is ≤ Grade 1, the paint film hardness is ≥350g, and the paint film thickness is ≥15μm on the plane and ≥18μm on the vertical surface. S123: electrophoresis inspection and polishing; Use a lemon sanding block and 320-grit garnet sandpaper to circularly sand the electrophoresis defects and repair the body defects after electrophoresis.

[0010] As a further description of the present invention, the pre-spraying treatment in the process of spraying the intermediate coating on the vehicle body comprises the following steps: S201: Grinding before midcoat; After the electrophoretic paint layer is completely dry and solidified, use 600# sandpaper to polish the entire surface of the car body to a matte finish; S202: Blow and wipe clean before mid-coating; Use a sticky cloth and the "S-type cleaning method" to clean the inside and outside surfaces of the car body, and use oil-free and water-free compressed air to blow the car body clean.

[0011] As a further description of the present invention, the spraying and drying in the process of spraying the intermediate coating on the vehicle body includes the following steps: S211: midcoat spraying; After wiping the car body, spray the intermediate paint. During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, and the paint temperature during the spraying process is 21-25℃; the volume ratio of intermediate paint: thinner: curing agent is 4:1:1. After spraying, the car body is flashed and leveled, and the leveling time is not less than 8min; S212: drying of intermediate coating; After leveling, the car body is heated in a drying oven to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. After drying, the total film thickness of the midcoat car body surface is 45-60μm. Thickness of single film of midcoat: vertical surface ≥30μm, flat surface ≥35μm; paint film adhesion ≤level 1, paint film hardness ≥HB.

[0012] As a further description of the present invention, the post-spraying treatment in the mid-coat spraying process of the vehicle body includes the following steps: S221: midcoat inspection and dry grinding; Use 600-grit garnet sandpaper to circularly grind the defects in the midcoat; S222: Blow and wipe the midcoat on the car body clean; Use oil-free and water-free compressed air to blow the car body clean and wipe the inside and outside surfaces of the car body clean.

[0013] As a further description of the present invention, the pre-spraying preparation in the process of spraying the vehicle body color paint includes the following steps: S301: Polishing before paint spraying; After the mid-coat spray paint layer is dry and solidified, use 600# sandpaper to polish the entire surface of the car body to a matte finish; S302: Blow and wipe the car body clean; Use oil-free and water-free compressed air to blow the car body clean and wipe the inside and outside surfaces of the car body clean.

[0014] As a further description of the present invention, the paint spraying and drying in the vehicle body paint spraying process includes two operations: 2K paint spraying and drying, and metallic paint or 1K paint spraying and drying. Among them, 2K paint spraying and drying includes the following steps: S311: 2K color paint spraying; During the spraying process, the temperature of the spray booth is 25-30℃, the humidity of the spray booth is 60-80%, the wind speed in the spray booth is 0.3-0.4m / s, the spray paint temperature is 25-30℃, and the volume ratio of 2K color paint: curing agent: diluent is 4:2:1; S312: 2K paint drying; After the 2K paint is leveled, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70℃ and the drying time is 25-35min. The single film thickness of the 2K paint is 30-45μm, the paint film adhesion is ≤1 level, and the paint film hardness is ≥HB. The spraying and drying of metallic paint or 1K paint includes the following steps: S313: Metallic paint or 1K paint spraying; During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, the spraying paint temperature is 25-30℃, the volume ratio of metallic paint or 1K paint: thinner is 1:1, and the car body is flash-dried and leveled after spraying, and the leveling time is not less than 8min; S314: Varnish spraying; During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, the spraying paint temperature is 25-30℃, the volume ratio of varnish: curing agent: diluent is 4:2:1, the varnish film thickness is 30-40μm, and the car body is flash-dried and leveled after spraying, and the leveling time is not less than 8min; S315: drying; After leveling, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. Among them, the film thickness of metallic paint or 1K color paint is 15-25μm, the film thickness of clear varnish spray is 30-40μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

[0015] As a further description of the present invention, the matte varnish spraying and drying in the vehicle body color paint spraying process includes the following steps: S321: Fine polishing of topcoat; After the paint is sprayed and dried, use P1200-P1500 sandpaper to dry sand the entire vehicle; S322: Matte varnish spraying; After polishing, clean the car body and spray matte varnish. During the spraying process, the temperature of the spray room is 25-30℃, the humidity of the spray room is 60-80%, the wind speed of the spray room is 0.3-0.4m / s, the paint temperature is 25-30℃, and the volume ratio of varnish: matte agent: curing agent: diluent is 1:1:1:2. After spraying, the car body is flash-dried and leveled, and the leveling time is not less than 8min; S323: Matt varnish drying; After leveling is completed, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. The matte varnish spray film thickness is 30-40μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

[0016] Compared with the prior art, the technical effects of the present invention are: The invention provides a satin spraying process, which comprises vehicle body electrophoresis, vehicle body mid-coat spraying and vehicle body color paint spraying in sequence, and forms a spray layer on the surface of a vehicle body, and the spray layer is formed by curing the coating after spraying. The specific coating comprises paint, thinner, curing agent, varnish and matte agent. Through the satin spraying process, a metal layer, an electrophoretic layer, a mid-coat layer, a color paint layer, a varnish layer and a matte varnish layer are sequentially included on the surface of the vehicle body. Through double-layer varnish spraying and a full matte coating process, the coating of the vehicle body has a soft gloss, a strong hazy feeling and a high diffuse reflectivity, and achieves a satin-like spraying effect, improves the texture of the paint of the whole vehicle, makes up for the defects of the conventional spraying process, and has a good market prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the spraying process flow of the present invention; Figure 2 It is a schematic diagram of the paint layer of the vehicle body after the spraying process of the present invention is completed; Figure 3 It is a schematic diagram of the spraying process effect of the present invention. DETAILED DESCRIPTION

[0018] The present invention is described in detail below in conjunction with the accompanying drawings: The present invention discloses a satin spraying process, which is used for body surface modification, including body surface decoration, beautification, etc. Specifically, the process includes body electrophoresis, body mid-coat spraying, and body color paint spraying in sequence; the spray layer is formed by spraying and curing the paint, and the paint components include paint, diluent, curing agent, varnish and matte agent; wherein, the body electrophoresis process includes pretreatment, electrophoresis coating and posttreatment, and the electrophoresis coating is set to three-stage voltage ladder control; after the paint layer of the body electrophoresis is completely dried and cured, the coating layer is sprayed with a pretreatment, a pretreatment is performed, and a posttreatment is performed. Car body mid-coat spraying; the process of car body mid-coat spraying includes pre-spraying treatment, spraying and drying, and post-spraying treatment, and the sprayed paint components include mid-coat paint, diluent, and curing agent; after the car body mid-coat spray paint layer is dried and cured, the car body color paint is sprayed; the process of car body color paint spraying includes pre-spraying preparation, color paint spraying and drying, matte varnish spraying and drying, the color paint includes any one of 2K color paint, metallic paint, and 1K color paint, and the color paint, curing agent and diluent are adjusted in proportion to spray the color paint.

[0019] refer to Figure 1-2 As shown, in one embodiment of the present invention, a satin spraying process is disclosed. In the spraying process, the above-mentioned color paint adopts 2K color paint. Specifically, this embodiment includes the following steps: 1. Car body electrophoresis (1) Preprocessing includes the following steps: S101: Pre-cleaning: The inner and outer surfaces of the vehicle body are sprayed with a high-pressure water gun. The spray pressure of the high-pressure water gun is 60-100 bar, and the water tank temperature of the high-pressure water gun is 30-45°C. After cleaning, there is no obvious oil stain, dust, iron filings and impurities; S102: Degreasing treatment: the car body is immersed in a tank liquid through pre-degreasing and degreasing to remove grease and pollution on the surface of the car body; Pre-degreasing is to immerse the car body in a pre-degreasing bath with a free alkalinity point of 10-18 and a Ph value of 10-13, the bath temperature is 30-45°C, and the immersion time is 278s; For degreasing, the car body is immersed in a degreasing bath with a free alkalinity point of 8-16 and a Ph value of 9-12, the bath temperature is 45-55°C, and the immersion time is 466s; S103: washing with water; washing the vehicle body surface with water for multiple times; Water washing 1 is to immerse the car body in a water washing tank with a Ph value of 7.5-9.5, alkaline dirt <1.5Pt, conductivity <1000us / cm, and accelerator point 0.6-2.0Pt, and the immersion time is 248s; Water washing 2 is to immerse the car body in a water washing tank with a Ph value of 7.5-9.5, alkaline dirt <1.5Pt, conductivity <800us / cm, and accelerator point 0.6-2.0Pt, and the immersion time is 248s.

[0020] (2) Electrophoretic coating includes the following steps: S111: Surface adjustment and phosphating: the surface of the car body is first adjusted, and then phosphating is performed; The surface adjustment is to immerse the vehicle body in a surface adjustment tank liquid with a conductivity of 1400±600μs / cm, a Ph value of 8.5-10, and a Zn point of 10-14 for 238s; Phosphating treatment involves immersing the car body in a phosphating bath with a total acid point of 20-24Pt, a free acid point of 0.8-1.2Pt, and an accelerator point of 1.5-2.5Pt. During the immersion process, the bath temperature is 45-50°C and the immersion time is 325s. After phosphating treatment, the phosphating film weight of the car body is 2.5-4g / m 2 , the phosphating crystal size is 3-10μm; S112: pure water washing: washing the vehicle body with pure water for multiple times to clean the vehicle body surface; Pure water washing 1 is to immerse the car body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <30μs / cm, and the immersion time is 244s; Pure water washing 2 is to immerse the car body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <30μs / cm, and the immersion time is 244s; Pure water washing 3 is to immerse the car body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <25μs / cm, and the immersion time is 345s; S113: electrophoresis; immersing the car body in the electrophoresis tank for electrophoresis coating, with a total immersion time of 642 seconds, and depositing the coating evenly on the surface of the car body through the electric field to form a protective film; The electrophoresis tank liquid is set to have a solid content of 19-23%, a Ph value of 5.6-6.2, an ash content of 15-20%, an MEQ of 25-30, a pigment-to-base ratio of 8-12, a solvent content of 0.6-2.5%, and a tank liquid conductivity of (1100-2000) μs / cm; during the immersion of the vehicle body, the temperature of the electrophoresis tank liquid is maintained at 30-32° C. The electrophoresis is controlled by a three-stage voltage ladder, with a first stage voltage of 80-150V and a time of 60-80s, a second stage voltage of 180-240V and a time of 60-120s, and a third stage voltage of 250-290V and a time of 280-340s; the vehicle body is connected to the cathode, and the corresponding anode liquid conductivity is less than 800 μs / cm, and the anode liquid Ph value is 2-6.

[0021] (3) Post-processing includes the following steps: S121: Ultrafiltration water washing and pure water washing: cleaning the vehicle body surface by multiple ultrafiltration water washing and pure water washing; Ultrafiltration washing 1 is to immerse the car body in ultrafiltration washing tank liquid, with solid content ≤1.1%, Ph value 5-6, ultrafiltration conductivity 400-1500μs / cm, and immersion time is 246s; Ultrafiltration water washing 2 is to immerse the car body in ultrafiltration water washing tank liquid, with solid content ≤ 0.5%, Ph value 5-6, ultrafiltration conductivity 400-1200μs / cm, and immersion time is 246s; Pure water washing 4 is to immerse the car body in a pure water washing tank liquid with a conductivity of less than 150μs / cm for 245s; Pure water washing 5 is to immerse the car body in a pure water washing tank with a conductivity of less than 100 μs / cm for 246 seconds; S122: Electrophoretic drying: After pure water washing, the paint film of the car body is dried to solidify the electrophoretic paint. The car body temperature during the drying process is 180℃~200℃ and maintained within this temperature range for 25-30min. After drying, the paint film adhesion of the electrophoretic paint is ≤ Grade 1, the paint film hardness is ≥350g, and the paint film thickness is ≥15μm on the plane and ≥18μm on the vertical surface. S123: Electrophoresis inspection and polishing: Manually use lemon polishing block and 320-grit garnet sandpaper to circularly polish the electrophoresis defects and repair the body defects after electrophoresis.

[0022] 2. Car body mid-coat spraying (1) Pre-spraying treatment includes the following steps: S201: Sanding before midcoating; Check and confirm that the electrophoretic paint layer is completely dry and solidified, that is, there is no stickiness when sanding with sandpaper; Use 600# sandpaper to sand the entire surface, and gently grind the particles and slag spots on the paint surface in circles. Pay attention to carefully sanding the edges, corners and paint layers at the junction of the workpiece and the tape; During the sanding process, ensure that the surface gloss layer is sanded to matte; Ensure that the sanding is uniform and thorough, without missing sanding, pits, and deep sandpaper patterns. If the sanding area is relatively large, use a pneumatic sander with 600# sandpaper for sanding according to the working conditions; S202: Blow and wipe clean before mid-coating; before the car body enters the mid-coating spraying, use a sticky cloth and the "S-type wiping method" to wipe the inner and outer surfaces of the car body, and use oil-free and water-free compressed air to blow clean the car body. After wiping, the car body is clean and free of floating dust, impurities and particles.

[0023] (2) Spraying and drying include the following steps: S211: mid-coat spraying; spray the mid-coat paint on the cleaned car body. During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, and the paint temperature during the spraying process is 21-25℃; the volume ratio of mid-coat paint: thinner: curing agent is 4:1:1. After spraying, the car body is flashed and leveled, and the leveling time is not less than 8min; S212: Drying of midcoat; after leveling, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70℃, and the drying time is 25-35min. After drying, the total film thickness of the midcoat car body surface is 45-60μm; the thickness of a single midcoat film: ≥30μm for the vertical surface and ≥35μm for the flat surface; the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

[0024] (3) Post-spraying treatment includes the following steps: S221: Inspection and dry grinding of midcoat; manual circular grinding of midcoat defects using 600-grit garnet sandpaper; S222: Blow and wipe the midcoat on the car body clean; wipe the inner and outer surfaces of the car body clean before spraying the color paint on the car body, and use oil-free and water-free compressed air to blow the car body clean. After blowing and wiping, the inner and outer surfaces of the car body are clean and free of floating dust, impurities and particles.

[0025] 3. Car body paint spraying (1) Preparation before spraying includes the following steps: S301: Sanding before color paint spraying; Check and confirm that the midcoat spray paint layer on the car body is dry and solidified, that is, there is no stickiness when sanding with sandpaper; Use 600# sandpaper to sand the entire body, and gently grind the paint surface particles and slag points in circles. Pay attention to carefully sanding the edges, corners and paint layers at the junction of the workpiece and the tape; During the sanding process, ensure that the surface gloss layer is sanded to matte; Ensure that the sanding is uniform and thorough, without missing sanding, pits, and deep sandpaper patterns. If the sanding area is relatively large, use a pneumatic sander with 600# sandpaper for sanding according to the working conditions; S302: Blow and wipe the car body clean; wipe the inner and outer surfaces of the car body clean before spraying the dark topcoat, and use oil-free and water-free compressed air to blow the car body clean. After blowing and wiping, the inner and outer surfaces of the car body are clean and free of floating dust, impurities and particles.

[0026] (2) In the process of paint spraying and drying, 2K paint spraying and drying includes the following steps: S311: 2K color paint spraying; during the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed in the spraying room is 0.3-0.4m / s, the spraying paint temperature is 25-30℃, and the volume ratio of 2K color paint: curing agent: diluent is 4:2:1; S312: 2K paint drying; After the 2K paint is leveled, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70℃ and the drying time is 25-35min. The single film thickness of the 2K paint is 30-45μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

[0027] (3) Matt varnish spraying and drying includes the following steps: S321: Fine grinding of topcoat; after spraying and drying the color paint, use P1200-P1500 sandpaper and pneumatic sander to dry grind the whole vehicle to remove paint film defects, eliminate orange peel texture, and increase the adhesion between coatings; S322: Matt varnish spraying; after polishing, wipe the car body clean and spray matte varnish. During the spraying process, the temperature of the spray room is 25-30℃, the humidity of the spray room is 60-80%, the wind speed of the spray room is 0.3-0.4m / s, the paint temperature is 25-30℃, and the volume ratio of varnish: matting agent: curing agent: diluent is 1:1:1:2. After spraying, the car body is flash-dried and leveled, and the leveling time is not less than 8min; S323: Matt varnish drying; after leveling, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70℃ and the drying time is 25-35min. The matte varnish spray film thickness is 30-40μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

[0028] In another embodiment of the present invention, the above-mentioned paint is metallic paint or 1K paint. In this embodiment, except for the steps of paint spraying and drying, the other steps are consistent with the above-mentioned embodiment.

[0029] Specifically, in this embodiment, during the spraying and drying of the paint, the spraying and drying of the metallic paint or 1K paint includes the following steps: S313: Metallic paint or 1K color paint spraying; during the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, the spraying paint temperature is 25-30℃, the volume ratio of metallic paint or 1K color paint: thinner is 1:1, and the car body is flashed and leveled after spraying, and the leveling time is not less than 8min; S314: Varnish spraying: after wiping clean, spray varnish on the car body. During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, the spraying temperature of the paint is 25-30℃, the volume ratio of varnish: curing agent: diluent is 4:2:1, the film thickness of the varnish is 30-40μm, and the car body is flashed and leveled after spraying, and the leveling time is not less than 8min; S315: Drying; After leveling, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. Among them, the film thickness of metallic paint or 1K color paint is 15-25μm, the film thickness of clear varnish spray is 30-40μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

[0030] Through the above two embodiments, the content of the present invention is disclosed. After the above satin coating process, the metal layer, electrophoretic layer, intermediate coating layer, color paint layer, varnish layer, and matte varnish layer are sequentially included on the surface of the automobile body. Through double-layer varnish spraying and full matte coating process, the automobile body coating has a soft gloss, a strong hazy feeling, and a high diffuse reflectivity, achieving a satin-like spraying effect, which improves the texture of the entire vehicle paint. The actual effect diagram of the car model after spraying is shown in the figure below. Figure 3 As shown, the present invention makes up for the defects of the conventional spraying process and has a good market prospect.

[0031] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A satin spraying process for body surface modification, characterized in that: The process includes body electrophoresis, body mid-coat spraying, and body color paint spraying in sequence; The electrophoretic coating process of the vehicle body includes pretreatment, electrophoretic coating and post-treatment, and the electrophoretic coating is set to three-stage voltage step control; after the electrophoretic paint layer of the vehicle body is dried and solidified, the vehicle body intermediate coating is sprayed; The process of spraying the midcoat on the vehicle body includes pre-spraying treatment, spraying and drying, and post-spraying treatment. The sprayed paint components include midcoat paint, diluent, and curing agent. After the midcoat sprayed paint layer on the vehicle body is completely dry and cured, the vehicle body color paint is sprayed; The process of spraying the car body paint includes preparation before spraying, paint spraying and drying, matte varnish spraying and drying, the paint includes any one of 2K paint, metallic paint, and 1K paint, and the paint, curing agent and diluent are adjusted in proportion for paint spraying.

2. A satin spraying process according to claim 1, characterized in that: The pretreatment during the electrophoresis process of the vehicle body includes the following steps: S101: Pre-cleaning; The inner and outer surfaces of the car body are sprayed with a high-pressure water gun. The spray pressure of the high-pressure water gun is 60-100 bar, and the water tank temperature of the high-pressure water gun is 30-45℃; S102: degreasing treatment; Through pre-degreasing and degreasing, the car body is immersed in a tank liquid to remove grease and pollution on the surface of the car body; wherein, the pre-degreasing is to immerse the car body in a pre-degreasing tank liquid with a free alkalinity point of 10-18 and a Ph value of 10-13, the tank liquid temperature is 30-45°C, and the immersion time is 278s; the degreasing is to immerse the car body in a degreasing tank liquid with a free alkalinity point of 8-16 and a Ph value of 9-12, the tank liquid temperature is 45-55°C, and the immersion time is 466s; S103: washing; After multiple water washings, the surface of the vehicle body is cleaned; water washing 1 is to immerse the vehicle body in a water washing tank with a Ph value of 7.5-9.5, alkali stains <1.5Pt, conductivity <1000us / cm, and accelerator points of 0.6-2.0Pt, and the immersion time is 248s; water washing 2 is to immerse the vehicle body in a water washing tank with a Ph value of 7.5-9.5, alkali stains <1.5Pt, conductivity <800us / cm, and accelerator points of 0.6-2.0Pt, and the immersion time is 248s.

3. A satin spraying process according to claim 2, characterized in that: The electrophoretic coating in the electrophoretic coating process of the vehicle body includes the following steps: S111: Surface conditioning and phosphating; The car body is first subjected to surface adjustment and then to phosphating treatment; the surface adjustment is to immerse the car body in a surface adjustment bath with a conductivity of 1400±600μs / cm, a Ph value of 8.5-10, and a Zn point of 10-14, and the immersion time is 238s; the phosphating treatment is to immerse the car body in a phosphating bath with a total acid point of 20-24Pt, a free acid point of 0.8-1.2Pt, and an accelerator point of 1.5-2.5Pt, and the bath temperature during the immersion of the car body is 45-50℃, and the immersion time is 325s; the phosphating film weight of the car body after phosphating treatment is 2.5-4g / m 2 , the phosphating crystal size is 3-10μm; S112: pure water washing; The vehicle body is washed with pure water for multiple times to clean the vehicle body surface; pure water washing 1 is to immerse the vehicle body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <30μs / cm for 244s; pure water washing 2 is to immerse the vehicle body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <30μs / cm for 244s; pure water washing 3 is to immerse the vehicle body in a pure water washing tank with acid stain <1.5Pt, Ph value >5, and conductivity <25μs / cm for 345s; S113: electrophoresis; The vehicle body is immersed in an electrophoretic tank for electrophoretic coating, the total immersion time is 642 seconds, and the coating is uniformly deposited on the surface of the vehicle body through the action of an electric field to form a protective film; the electrophoretic tank is set to have a solid content of 19-23%, a Ph value of 5.6-6.2, an ash content of 15-20%, an MEQ of 25-30, a pigment-to-base ratio of 8-12, a solvent content of 0.6-2.5%, and a tank conductivity of (1100-2000) μs / cm; during the immersion of the vehicle body, the temperature of the electrophoretic tank is maintained at 30-32° C. The electrophoresis is controlled by a three-stage voltage ladder, wherein the first stage voltage is 80-150V and the time is 60-80s, the second stage voltage is 180-240V and the time is 60-120s, and the third stage voltage is 250-290V and the time is 280-340s; the vehicle body is connected to a cathode, and the corresponding anode liquid conductivity is less than 800 μs / cm, and the anode liquid Ph value is 2-6.

4. A satin spraying process according to claim 3, characterized in that: The post-processing of the vehicle body during electrophoresis includes the following steps: S121: ultrafiltration water washing and pure water washing; The surface of the vehicle body is cleaned by multiple ultrafiltration water washing and pure water washing; ultrafiltration water washing 1 is to immerse the vehicle body in ultrafiltration water washing tank liquid, with a solid content of ≤1.1%, a Ph value of 5-6, an ultrafiltration conductivity of 400-1500μs / cm, and an immersion time of 246s; ultrafiltration water washing 2 is to immerse the vehicle body in ultrafiltration water washing tank liquid, with a solid content of ≤0.5%, a Ph value of 5-6, an ultrafiltration conductivity of 400-1200μs / cm, and an immersion time of 246s; Pure water washing 4 is to immerse the vehicle body in a pure water washing tank with a conductivity of less than 150 μs / cm for 245 seconds; pure water washing 5 is to immerse the vehicle body in a pure water washing tank with a conductivity of less than 100 μs / cm for 246 seconds; S122: electrophoresis drying; The paint film of the car body is dried to solidify the electrophoretic paint. The car body temperature during the drying process is 180℃~200℃ and maintained within this temperature range for 25-30min. After drying, the paint film adhesion of the electrophoretic paint is ≤ Grade 1, the paint film hardness is ≥350g, and the paint film thickness is ≥15μm on the plane and ≥18μm on the vertical surface. S123: electrophoresis inspection and polishing; Use a lemon sanding block and 320-grit garnet sandpaper to circularly sand the electrophoresis defects and repair the body defects after electrophoresis.

5. A satin spraying process according to claim 1, characterized in that: The pre-spraying treatment in the process of spraying the intermediate coating on the vehicle body includes the following steps: S201: Grinding before midcoat; After the electrophoretic paint layer is completely dry and solidified, use 600# sandpaper to polish the entire surface of the car body to a matte finish; S202: Blow and wipe clean before mid-coating; Use a sticky cloth and the "S-type cleaning method" to clean the inside and outside surfaces of the car body, and use oil-free and water-free compressed air to blow the car body clean.

6. A satin spraying process according to claim 5, characterized in that: The spraying and drying in the process of spraying the intermediate coating on the vehicle body includes the following steps: S211: midcoat spraying; After wiping the car body, spray the intermediate paint. During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, and the paint temperature during the spraying process is 21-25℃; the volume ratio of intermediate paint: thinner: curing agent is 4:1:

1. After spraying, the car body is flashed and leveled, and the leveling time is not less than 8min; S212: drying of intermediate coating; After leveling, the car body is heated in a drying oven to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. After drying, the total film thickness of the midcoat car body surface is 45-60μm. Thickness of single film of midcoat: vertical surface ≥30μm, flat surface ≥35μm; paint film adhesion ≤level 1, paint film hardness ≥HB.

7. A satin spraying process according to claim 6, characterized in that: The post-spraying treatment in the process of spraying the intermediate coating on the vehicle body comprises the following steps: S221: midcoat inspection and dry grinding; Use 600-grit garnet sandpaper to circularly grind the defects in the midcoat; S222: Blow and wipe the midcoat on the car body clean; Use oil-free and water-free compressed air to blow the car body clean and wipe the inside and outside surfaces of the car body clean.

8. The satin spraying process according to claim 1, characterized in that: The pre-spraying preparation in the process of spraying the body paint includes the following steps: S301: Polishing before paint spraying; After the mid-coat spray paint layer is dry and solidified, use 600# sandpaper to polish the entire surface of the car body to a matte finish; S302: Blow and wipe the car body clean; Use oil-free and water-free compressed air to blow the car body clean and wipe the inside and outside surfaces of the car body clean.

9. A satin spraying process according to claim 8, characterized in that: The paint spraying and drying in the process of spraying the car body paint includes two operations: 2K paint spraying and drying, and metallic paint or 1K paint spraying and drying. Among them, 2K paint spraying and drying includes the following steps: S311: 2K color paint spraying; During the spraying process, the temperature of the spray booth is 25-30℃, the humidity of the spray booth is 60-80%, the wind speed in the spray booth is 0.3-0.4m / s, the spray paint temperature is 25-30℃, and the volume ratio of 2K color paint: curing agent: diluent is 4:2:1; S312: 2K paint drying; After the 2K paint is leveled, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70℃ and the drying time is 25-35min. The single film thickness of the 2K paint is 30-45μm, the paint film adhesion is ≤1 level, and the paint film hardness is ≥HB. The spraying and drying of metallic paint or 1K paint includes the following steps: S313: Metallic paint or 1K paint spraying; During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, the spraying paint temperature is 25-30℃, the volume ratio of metallic paint or 1K paint: thinner is 1:1, and the car body is flash-dried and leveled after spraying, and the leveling time is not less than 8min; S314: Varnish spraying; During the spraying process, the temperature of the spraying room is 25-30℃, the humidity of the spraying room is 60-80%, the wind speed of the spraying room is 0.3-0.4m / s, the spraying paint temperature is 25-30℃, the volume ratio of varnish: curing agent: diluent is 4:2:1, the varnish film thickness is 30-40μm, and the car body is flash-dried and leveled after spraying, and the leveling time is not less than 8min; S315: drying; After leveling, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. Among them, the film thickness of metallic paint or 1K color paint is 15-25μm, the film thickness of clear varnish spray is 30-40μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

10. A satin spraying process according to claim 9, characterized in that: The matte varnish spraying and drying in the vehicle body color paint spraying process includes the following steps: S321: Fine polishing of topcoat; After the paint is sprayed and dried, use P1200-P1500 sandpaper to dry sand the entire vehicle; S322: Matte varnish spraying; After polishing, clean the car body and spray matte varnish. During the spraying process, the temperature of the spray room is 25-30℃, the humidity of the spray room is 60-80%, the wind speed of the spray room is 0.3-0.4m / s, the paint temperature is 25-30℃, and the volume ratio of varnish: matte agent: curing agent: diluent is 1:1:1:

2. After spraying, the car body is flash-dried and leveled, and the leveling time is not less than 8min; S323: Matt varnish drying; After leveling is completed, the car body is heated in a drying furnace to convert the paint film into a solid state. During the drying process, the car body temperature is 65-70°C and the drying time is 25-35 minutes. The matte varnish spray film thickness is 30-40μm, the paint film adhesion is ≤level 1, and the paint film hardness is ≥HB.

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