Coating durability is the performance of prepainted steel coils during use, which is usually measured by aesthetic life and first overhaul life.
Ⅰ. The beautiful life of prepainted steel coils
The time interval from the completion of the manufacture of the prepainted steel coil to the occurrence of a certain degree of discoloration and chalking of the surface coating, which affects the original aesthetic effect of the coating.
Ⅱ. The limit life of prepainted steel coils
The steel plate is corroded and perforated and cannot be used.
Ⅲ. Coating thickness of prepainted steel coils
1. Poly and hollow tissue coating
Microscopically, the coating is a porous structure, and water and corrosive media (chloride ions, etc.) in the air will invade through the weak part of the coating, causing corrosion under the film, and then the coating will blister and peel off.
2. Coating thickness selection
The front coating ≥ 20μm can effectively prevent the intrusion of corrosive media. Because the anti-corrosion mechanism of primer and topcoat is different, the thickness of primer and topcoat should be respectively required. Only in this way can the resistance of different parts of the prepainted steel coil be guaranteed. Corrosion is balanced.
Ⅳ. Coating gloss of prepainted steel coils
1. Light pollution
High gloss surface glare High reflectivity of sunlight during the day can cause light pollution.
2. Safety hazard
The high-gloss surface has a small friction coefficient and is easy to slip. During roof construction, the high-gloss prepainted steel coil is likely to bring safety hazards.
3. Visual fatigue
The aging of prepainted steel coils when used outdoors first means loss of gloss. When maintenance is required, it is easy to distinguish between the old and new steel plates, resulting in poor appearance; if the back paint is high-gloss, it is easy to produce halo when there is light indoors. Visual fatigue of personnel.
Ⅴ. Coating color of prepainted steel coils
1. light color
From the technical point of view, the pigments of light-colored paints have a large choice of pigments, and inorganic paints with superior durability can be selected, and the heat-reflecting ability of the paints is strong. The temperature of the coating itself is relatively low in summer, which is beneficial to prolonging the life of the coating. .
In addition, even if the coating is discolored or chalked up, the contrast between the light color prepainted steel coils coating and the original color after the change is small, and the effect on the appearance is not great.
2. Dark color
Dark colors (especially bright colors) are mostly organic colors, which are easy to fade when exposed to ultraviolet rays, and the color changes in the shortest 3 months.
According to relevant experimental data, when the outside temperature is the highest at noon in summer, the temperature of the white surface is 10°C lower than that of the blue surface and 19°C lower than that of the black surface, and the reflection ability of different colors to sunlight is different.
Ⅵ. What is the reason for the lack of luster on the surface of prepainted steel coils?
1. The surface of the substrate is too rough or contains oil, moisture, wax, etc., and the coating is not fully cured.
2. The paint of the prepainted steel coil is not sufficiently mixed before the machine is put on the machine, and the solid of the paint settles at the bottom of the barrel, so that there is less pigment in the upper half of the barrel during construction.
3. Excessive addition of diluent to the coating dilutes the effect of the glossy coating on the prepainted steel coil.
4. The reason for the formula of the prepainted steel coil coating is that the amount of pigments, fillers and solvents in the coating is too much, the fineness is not enough or there is dust.
5. The surface coating of the prepainted steel coil is too thin, and the temperature of the roller coating room is too high or too low during construction. In addition, if the temperature of the curing furnace is set too high, the amount of hot air circulation in the furnace is insufficient, and the coating is over-baked, which will also cause the surface of the prepainted steel coil to be dull.
Therefore, when using, the above problems should be avoided to ensure the gloss of the surface of the prepainted steel coil.
Quality Management: In terms of quality control and assurance, EAST STEEL CO., LTD has been adhering to high standards and requirements. As we all know, the service life of prepainted color coated steel coil mainly depends on the nature and thickness of the surface coating. At present, all-steel mills' commitments to the external warranty period are made by their paint suppliers to the steel mills. The pursuit of EAST STEEL CO., LTD is to make products that everyone can trust and products that everyone likes.