1.What is the core function of the back coating of color coated coils?
The core function of color coated coils is to protect the substrate (steel plate/aluminum plate) from corrosion through coating, while the main function of the back coating is to prevent corrosion, moisture and avoid scratches during transportation/installation, rather than decoration.
2.Why is the back of color coated coil mostly grayish white?
Off-white is usually made from white pigments such as titanium dioxide (titanium dioxide) or zinc oxide. These pigments have certain chemical stability, which can enhance the weather resistance and hiding power of the coating and effectively prevent moisture and humidity from eroding the substrate.
The back coating is thinner (usually 5-10μm, and the front coating is mostly 20-30μm). The off-white pigment has strong hiding power and can evenly cover the substrate even with a thin coating, avoiding early rust caused by partial exposure of the bottom.
3.What impact does the off-white back side of the color-coated coil have on the cost?
Color pigments (such as red, blue, etc.) cost more than white pigments (titanium dioxide is the most cost-effective white pigment in the industry). The back does not need decorative functions, and the use of off-white can reduce the consumption of high-priced pigments and reduce overall production costs.
The amount of resin and formula of the back coating are also relatively simple (such as using ordinary polyester instead of fluorocarbon resin with stronger weather resistance). The combination of off-white pigments can further reduce costs without affecting the basic anti-corrosion performance.
4.What production convenience does the off-white back side of the color-coated coil bring?
Off-white is a "neutral color" that is more compatible with various color coatings on the front side, and will not affect the consistency of the front color due to the penetration or superposition of the back color (for example, if the back side is dark, the front side may have color differences due to minor defects in the coating).
The same production line can quickly switch colors by adjusting the front side pigment, while the back side is fixed to off-white, without the need to frequently clean the roller coating equipment or adjust the formula, thus improving production efficiency.
5.Special cases: What are the scenarios where the back side is not off-white?
In a few scenarios, the back of the color-coated coil may use other colors (such as light gray, black), but the essence still serves the functional needs:
For indoor and outdoor scenes (such as partitions, ceilings), the back may need to coordinate the color with the front, but it is still mainly light colors (to avoid heat absorption or dirtiness).
For special functional color-coated coils (such as heat insulation), the back may use silver (aluminum powder) with added heat insulation fillers, but the core is still "non-decorative" functional color matching.