Breakthrough In Deep Processing Technology Of Prepainted Steel Coils

1. Primers: Enhance adhesion between substrate and topcoat, and strengthen anti-corrosion foundation

• Epoxy Primer: It has extremely strong adhesion, good compatibility with galvanized steel plates and cold-rolled steel plates, and excellent chemical corrosion resistance. It can effectively block the contact between the substrate and external moisture and salt, making it the mainstream primer in the home appliance and building materials fields.
• Polyester Primer: It has high compatibility with polyester topcoats and good coating flexibility. Suitable for deep processing scenarios that require subsequent bending and stamping, it balances anti-corrosion and processing performance.

2. Topcoats: Determine product appearance and core weather/durability performance

• General Polyester Topcoat: It has high cost-effectiveness and optional glossiness (high gloss, flat gloss). With moderate weather resistance, it is suitable for non-outdoor scenarios such as indoor home appliances (refrigerator side panels, washing machine casings) and indoor decorative parts.
• Silicon-Modified Polyester (SMP) Topcoat: Silicon resin is introduced into polyester, significantly improving weather resistance (no easy fading or chalking after 5-8 years of outdoor exposure). It also has good solvent resistance and is often used in outdoor light steel structures (workshop cornices, exterior walls of temporary buildings).
• Polyvinylidene Fluoride (PVDF) Topcoat: It has top-tier weather resistance (15-20 years of outdoor service life), excellent UV resistance, acid rain resistance, and high-low temperature resistance (-40℃~150℃). With strong color stability, it is mostly used in high-end outdoor scenarios, such as large building curtain walls and exterior walls of airport terminals.
• Acrylic Topcoat: It has high glossiness and bright colors. Its weather resistance is better than that of general polyester but weaker than SMP. It is suitable for lightweight indoor and outdoor applications with high appearance requirements (such as advertising signs and decorative panels).

3. Backcoats: Strengthen protection for the back of coils and avoid damage during processing/storage

• Epoxy Backcoat: It has strong corrosion resistance and good adhesion to substrates, suitable for humid environments (such as cold storage and basement ceilings).
• Polyester Backcoat: It has good flexibility, no easy cracking during coil winding and transportation, and is compatible with most general scenarios. Its cost is lower than that of epoxy backcoats.