What are the disadvantages of electrophoretic paint film? Zaoyang Sihai Daopu Chemical Co., Ltd. gives you a detailed introduction:
1. Undercut
When applying the same or different coatings on the dry paint film, the dry film under it will soften, bulge or detach from the substrate during the coating application or drying period (usually the appearance is wrinkled).
Cause: The next coat of paint is applied before the coating is completely dry; The compatibility of the coating is poor, and the solvent of the finish coat can swell the primer; Too thick.
Solution: The primer shall be dry and then the finish coat shall be applied, or the finish coat shall be applied after the solvent volatilizes; Correctly select the coating type, pay special attention to the matching of the primer and finish; In terms of construction, one coat is thin and the other is thick.
2. Dry spray
The liquid coating has been semi-dry before reaching the surface of the coating, but there is still a certain amount of humidity that can just attach to the surface to form a film, but it can not form a continuous and effective paint film. Due to the loss of some solvents during dry spraying "particles" on the way to the coating, semi-dry paint dust is formed with poor adhesion or even no adhesion.
Cause: the painting distance is too far; The gun is curved or inclined; The ambient temperature is too high or there is strong wind; The spray gun pressure is too high; The solvent volatilizes too fast.
Solution: select appropriate solvents, or add some organic solvents with high boiling point that volatilize slowly; The spraying distance shall be properly selected to reduce the wind speed in the painting room.
3. Orange peel
The paint film has the appearance defect of orange peel.
Cause: solvent volatilizes too fast; The leveling property of the coating itself is poor, and the viscosity of the coating is high; Insufficient spraying pressure and poor atomization; The spraying distance is not appropriate. If it is too far, the spray gun runs fast; The wind speed in the paint booth is too high, the temperature is too high, or the paint enters the oven too early for drying; Insufficient film thickness; The coated surface is not smooth, which affects the leveling or absorption of the coating.
Solution: select appropriate solvents, or add some organic solvents with high boiling point that volatilize slowly; Low construction viscosity is selected through test; Good atomization shall be achieved during spraying; The spraying distance shall be properly selected to reduce the wind speed in the painting room; Drying room shall be set before the coated material enters the high-temperature drying furnace after spraying; The thickness of one layer of spraying shall meet the requirements; The coated surface shall be fully wet polished to make it flat and smooth; Add appropriate leveling agent.
