PPGI PPGL Galvanized Steel Coil performance: the key to determining the life and value of coated steel coils
PPGI/PPGL steel coils are coiled products made by surface pretreatment, coating (primer, topcoat, back paint), baking, and curing metal substrates (usually galvanized steel or aluzinc steel coils) on a continuous production line. The paint coating is the "outer coat" and "shield" of the color-coated coils, and its performance directly determines the final quality, service life, appearance retention, and application value of the product.
1. Adhesion
Definition: The strength of the bond between the paint coating and the metal substrate (or primer layer).
Importance: This is the basis of all performance! Without good adhesion, other performance is out of the question. Poor adhesion will cause the coating to blister and peel off, and lose its protective effect.
Test method: The commonly used cross-hatch method or X-scratch method is used to grade by observing the coating peeling after the tape is peeled off.
2. Corrosion Resistance
Definition: The ability of a coating to resist erosion by environmental factors (such as moisture, oxygen, salt spray, chemicals) and protect the substrate from rust.
Importance: Directly related to the service life of PPGI PPGL Galvanized Steel Coil, especially in highly corrosive environments such as coastal areas and industrial pollution areas.
Test method:
Salt spray test (NSS): Simulates a marine or de-icing salt environment, observes blistering at the scratch, rust spread width, and substrate corrosion. The longer the time (such as 1000 hours, 2000 hours), the better the performance.
3. Weathering Resistance/Light Fastness
Definition: The ability of a coating to resist the effects of sunlight (especially ultraviolet UV), rain, temperature changes, humidity, and other atmospheric environmental factors, and to maintain stable color and gloss without cracking or powdering.
Importance: It determines the appearance retention of color-coated coils after long-term use, and is crucial for applications with high appearance requirements, such as building exterior walls.
Test method:
Accelerated aging test:
Xenon Arc: simulates full-spectrum sunlight.
QUV mainly strengthens the damaging effects of UV.
Florida, Arizona: the most realistic but time-consuming (usually 5 or 10 years).
4. Mechanical Properties
Flexibility/Impact Resistance
Definition: The ability of the coating to resist physical deformation, such as bending and impact, without cracking or peeling.
Importance: Ensure that the coating remains intact when the color-coated coil is subjected to external force impact during processing and forming (such as rolling, bending, deep drawing) and use.
Test method: T-bend test, impact test.
Hardness:
Definition: The ability of the coating surface to resist indentation or scratching.
Importance: Affects wear resistance, scratch rresistanceand stain resistance.
Test method: Pencil hardness(Such as H, 2H, 3H... the larger the value, the harder it is.)
5. Coating Thickness & Weight
Measurement: Use a paint film measuring instrument to measure the total thickness and the thickness of each layer.
