Pretreatment method for coating surface of automobile paint booth

Pretreatment method for coating surface of automobile paint booth

The purpose of pretreatment of the car paint booth is to remove the foreign matter carried by the painted parts and provide a good substrate suitable for the painting requirements to ensure that the coating has good anti-corrosion and decorative properties. The specific pre-painted surface What are the treatment methods?

1, physical formula:

①Remove impurities adhering to the surface of the steel plate, and use a thinner to remove grease and other dirt.

②If there is sulfate or corrosive salt, it should be washed with clean water and dried with compressed air.

③On the steel plate pretreatment line, use shot blasting or sand blasting to remove oxide scale, rust and other impurities, and then remove the steel surface with a vacuum cleaner or purified compressed air.

2, chemical formula:

① Immersion type, spray type, immersion spray combined type, spray-dip-spray combined type.

②Pickling, phosphating slag removal and oil-water separation equipment are the key systems. Phosphating slag removal has sedimentation method, hydrocyclone separation method, inclined plate precipitation method, bag filter method, plate and frame filter press and other common methods.

③ Oil-water separation mainly includes: adsorption method, ultrafiltration method, hot oil separation method and centrifugal method.

3. The pretreatment of coating surface includes four processes:

1) Electrolysis (decomposition)

At the beginning of the cathode reaction is an electrolysis reaction to generate hydrogen and hydroxide ion OH. This reaction causes a high alkaline boundary layer to form on the cathode surface. When the cations and hydroxide radicals react to become water-insoluble substances, the coating film deposits. The equation is ：H2O→OH+H

2) Electrophoresis (migration, migration) the cationic resin and H+ move to the cathode under the action of an electric field, while the anions move to the anode.

3) Electrodeposition (precipitation)

On the surface of the coated workpiece, the cationic resin reacts with the surface of the cathode to neutralize and precipitate non-deposits, which are deposited on the coated workpiece.

4) Electroosmosis (dehydration)

The coating solids and the coating film on the surface of the workpiece are translucent, with many pores. Water is drained from the cathode coating film. Under the action of the electric field, the coating film is dehydrated, and the coating film is adsorbed on the surface of the workpiece. , And complete the entire electrophoresis process.

The pretreatment of the coating surface of the car paint booth can keep its beauty and prolong its service life. Therefore, in order to reduce our costs in all aspects, we have to deal with it in this way.