Color coated coil is a high-performance material produced by applying one or more layers of organic paint onto the surface of a galvanized (GI) or galvalume (GL) steel substrate, followed by baking and curing. It combines excellent corrosion resistance with superior decorative appeal, making it widely used in construction, home appliances, transportation, and industrial applications.

1. Structure of Prepainted Steel Coil

A high-quality prepainted steel coil typically consists of three main components:

Base Metal – Usually Hot-Dip Galvanized Steel Coil (GI) or Galvalume Steel Coil (GL), providing mechanical strength and fundamental corrosion resistance.

Coating System – Includes primer, top coat, and back coat applied via continuous coil coating and curing process, ensuring strong adhesion to the substrate.

Protective Film (Optional) – Applied to prevent surface scratches during transportation and fabrication; can be removed before installation.

2. Main Types of Prepainted Steel Coil

By Substrate Type:

PPGI (Prepainted Galvanized Steel Coil) – Base metal is hot-dip galvanized steel, suitable for environments with standard corrosion resistance requirements.

PPGL (Prepainted Galvalume Steel Coil) – Base metal is 55% aluminum-zinc alloy coated steel, offering superior corrosion resistance, especially in harsh outdoor environments.

By Coating Type:

PE (Polyester) – Cost-effective, bright colors, good overall performance; suitable for roofing, wall panels, and decorative purposes.

SMP (Silicone-Modified Polyester) – Improved weather and scratch resistance; ideal for high UV exposure and temperature fluctuation areas.

PVDF (Polyvinylidene Fluoride) – Exceptional weather resistance and color retention; lifespan can exceed 20 years; recommended for coastal, chemical, or high-end architectural projects.

3. Key Features

Excellent Corrosion Resistance – Dual protection from metallic coating and organic paint layer.

Aesthetic Appeal – Wide range of colors and surface finishes; custom colors available based on RAL standards.

Good Formability – Suitable for bending, roll forming, and punching without cracking or peeling.

UV and Weather Resistance – Maintains color stability and coating integrity over long-term outdoor exposure.

Eco-Friendly – High coating adhesion reduces the need for secondary painting, lowering environmental impact.

4. Typical Applications

Construction – Roofing sheets, wall cladding, sandwich panels, prefabricated houses, light steel structures

Home Appliances – Refrigerator panels, washing machine casings, air conditioner housings

Transportation – Container panels, truck bodies, marine storage facilities

Industrial and Agricultural – Machinery covers, warehouses, greenhouses

Advertising & Decoration – Outdoor billboards, partition panels, doors

5. Selection Guide

Indoor or Low-Corrosion Environments – PPGI with PE coating for cost-effective performance.

High UV or Extreme Temperature Areas – PPGI/PPGL with SMP coating for enhanced durability.

Coastal or Highly Corrosive Environments – PPGL with PVDF coating for maximum protection.

Color Requirements – Customizable according to RAL color chart to match architectural style or branding.

6. Common International Standards

ASTM A755 / ASTM A792 – United States

EN 10169 – European Union

JIS G3312 – Japan