PPGI & PPGL

PPGI (Pre‑Painted Galvanized Iron) and PPGL (Pre‑Painted Galvalume) are continuous coil‑coated pre‑painted steel coils, also known as color‑coated steel coils. Manufactured from hot‑dip metallic‑coated steel substrate, through pre‑treatment, primer application and top‑coat baking‑curing. Organic protective & decorative coating is formed on surface. Combine mechanical strength of steel with corrosion‑resistance, weather‑resistance and decorative colors of organic paint. Can be directly bent and profiled without on‑site painting. Widely used for building roofing & wall cladding, home‑appliance, transportation and ventilation components.

PPGI Pre‑Painted Galvanized Steel

Substrate: hot‑dip galvanized GI steel coil, pure zinc metallic coating. Double‑side zinc coating mass Z60‑Z275 g/m². Zinc provides sacrificial cathodic protection for cut edges and scratches. Excellent formability, cost‑effective, preferred for ordinary inland projects.

PPGL Pre‑Painted Galvalume Steel

Substrate: hot‑dip Galvalume GL steel coil. Alloy coating: 55 % Al +43.4 % Zn +1.6 % Si. Double‑side coating mass AZ70‑AZ150 g/m². Aluminum forms dense passive barrier, superior atmospheric corrosion‑resistance, heat‑resistance and heat reflectivity versus PPGI. Preferred for coastal, salt‑spray and industrial corrosive environments. Sacrificial protection at cut edges is weaker than PPGI; scratched areas are less protected.

1. Main Types

1. By top‑coat paint system

‑PE Polyester: Cost‑effective, general construction, outdoor service life 8‑12 years. ‑SMP Silicone‑Modified Polyester: Better anti‑chalking than PE, for factory roofing. ‑HDP High‑Durability Polyester: Medium‑long outdoor weather resistance, 12‑18 years. ‑PVDF Polyvinylidene Fluoride: High UV‑resistance, premium coastal projects, service life 20‑25 years.

2. By substrate grade

‑PPGI: DX51D+Z, SGCC, Q235B; zinc coating Z60‑Z275 g/m². ‑PPGL: DX51D+AZ, SGCC‑AZ; Al‑Zn coating AZ70‑AZ150 g/m².

3. Size range

Thickness: 0.15‑2.0 mm; width:600‑1500 mm; coil inner diameter:508/610 mm. Available as flat sheet, profiled sheet, slit strips. Back‑side back‑paint:5‑10 μm.

2. Layer Structure (from inner to outer)

Steel substrate → Hot‑dip metallic coating (Zn / Al‑Zn‑Si) → Conversion coating → Epoxy primer (5‑10 μm) → Top‑coat (15‑30 μm); back‑paint 5‑10 μm.

3. Key Features

‑PPGI: Good sacrificial protection at cut edges, excellent bending formability; cost‑effective solution for inland factories & warehouses; limited service life under coastal salt‑spray. ‑PPGL: Higher corrosion‑resistance, heat‑resistance and UV‑resistance; service life 2‑4 times PPGI under equal coating mass; suitable for coastal, high‑temperature & industrial corrosive conditions. Weaker sacrificial protection at cut edges, edge sealing is recommended after cutting. ‑Common features: Roll‑formable & bendable; customizable RAL colors; eliminates on‑site painting. Avoid coating scratches during handling.

4. Typical Applications

Factory roofing & wall panels, warehouses, steel‑structure envelopes, profiled tiles, fencing; home‑appliance shells, ventilation ducts, electrical cabinets; billboards, vehicle interior panels. PPGI for ordinary inland sites; PPGL for coastal, salt‑spray and industrial zones.

5. Standards

‑China: GB/T 12754‑2019 Color‑coated steel sheets and strips ‑International: ASTM A755M, EN 10169; JIS G 3312, JIS G 3318 ‑Russian reference: ГОСТ Р 52146‑2003 Pre‑painted metal‑coated steel sheets. EAC declaration required for EAEU export.

6. Selection Guidance

1. Inland ordinary factory, budget‑sensitive: choose PPGI with Z100‑Z180 zinc coating, PE/SMP top‑coat.
2. Coastal, salt‑spray, industrial areas: choose PPGL with AZ100‑AZ150 Al‑Zn substrate, HDP/PVDF top‑coat.
3. Complex bent profiles: prefer PPGI for better sacrificial edge protection.
4. Specify paint system, coating mass, thickness tolerance, RAL color; require adhesion, T‑bend and salt‑spray test reports.
5. Seal cut edges of PPGL after cutting to retard edge‑corrosion.

Details