one. Poor solvent resistance
Characteristic: Butanone wipe a little paint off.
Causes: 1. Baking temperature did not meet the requirements. 2. The curing of coatings is problematic. 3. The cleaning of pretreatment is not clean.
Two. Leakage coating
Features: Unpainted topcoat.
Reasons: 1. The edge finish is not coated, the base plate is not good or the pressure between the coating roll and the big back roll is insufficient. 2. The interior finish of the board surface is not coated. After the primer is cooled, there is water or other foreign matter on the board surface.
there. poor bending (T-bend)
Characteristic: During 180 degree bending test of steel, cracks and peeling of coating occur in the processing part.
Causes: 1. Excessive mastery of pretreatment. 2. Coating thickness is too thick. 3. Overbaking. 4. Undercoated paint is different from the manufacturer of coated paint, or the use of thinner materials is improper.
four. Poor Hardness (Pencil Hardness)
Characteristic: Drawing pencil is used to scratch hard on the coating surface, leaving a scratch on the surface after erasing.
Causes: 1. Low furnace temperature and insufficient curing of coating. 2. inappropriate heating conditions. 3. The thickness of the coating is thicker than the prescribed thickness.
This is the introduction of common quality problems of color coated steel plate.