Prepainted Steel Sheets: Category and film thickness of primers

Category and film thickness of primers

The category of the primer includes epoxy, polyester, acrylicacid, polyurethane, etc.
In general, the primer is chosen in accordance with the usage,environment condition, processing stage and finish coat. Thefilm thickness ofthe primer is usually 5-7 um.

(1) Epoxy primer

The epoxy primer has a strong adhesion to the base metal and good properties in waterproof, alkali-proof andchemical resistance, which is the original primer for thecoiled steel, having a poorer flexibility than that of otherprimers.

(2) Polyester primer

The primer has strong adhesion to the base metal andexcellent flexibility, which is relatively sensitive to dampenvironment and has a chemical resistance poorer thanthat of epoxy primer.

(3) Water-soluble acrylic acid primer

The primer of this kind has strong adhesion, excellentflexibility, lower organic solvent and low-temperature curing.

(4) Polyurethane primer

The primer of this kind has excellent chemical resistancedurability and flexibility.