Roller Coating Process of PVDF Color Coated Aluminum Coil

The roll coating process is an effective method to coat color coated aluminum with organic protective coatings. As a continuous and highly automated process, it helps to produce pvdf color coated aluminum coil rolls of better consistency than those from post-coating methods. Typical coating line systems require aluminium substrates of good moulding property, satisfying scratch-proof ability, beautiful appearance, excellent weather resistance and favorable adaptability to paints. In the coating line aluminum substrates are degreased, chemically pretreated and finally coated. The specific roller coating process is as below.

1. Feeding

An uncoated aluminium coil roll is sent to the production line and leveled by the leveling machine, which ensures good leveling of the roll that then enters the storage rack. There are two reels here to ensure that one of them is always in standby state. When the aluminium coil roll is about to complete the processing procedure, it must stop to get its tail seamed or welded with the head of another coil roll. Then, the storage rack is emptied and the production line runs continuously.

2. Pretreatment

The pretreatment of aluminium coil is realized by repeated water spraying, which proves to be more effective than traditional methods. It’s also more energy-saving because cleaning water can be reused. The necessity of pretreatment lies in its effective improvement in anti-corrosion performance of aluminum rolls and the adhesion of coatings. At the same time, a conversion film is formed on the surface of aluminium by chemical methods, which eventually improves quality of pvdf color coated aluminum coil.

3. Coating

The coating process consists of two stages, namely, bottom coating and surface coating. In the first stage, the aluminium roll is coated with primer on one or both sides. And in the second it goes through two roll coating machines which coats its single or double sides with the facial paint. Up to now the roll becomes a primary pvdf color coated aluminum coil roll.

4. Solidification

The coated roll goes through a furnace whose temperature is set at a regulated rate to ensure that the volatiles are removed and the coating is completely cured. According to the needs of the coating system, the curing temperature is usually set between 200 and 300 degrees Celsius, which is the key technology to ensure the quality of our products. In addition, in order to protect the environment and control the cost, the solvent mist is evaporated at high temperature to heat the curing furnace.

5. Further Processing

Finished pvdf color coated aluminum coil rolls can be further processed into other shapes, such as rolling gates, aluminum strips, embossed aluminum sheets and so on.