Anodic dip painting

The anodic dip painting (ATL) is an electrochemical coating process. Here, the object to be painted is in an electrically conductive aqueous electrodeposition paint immersed and a DC electric field between object to be painted and a counter electrode applied. In the ATL , the item to be painted is connected as the anode , the counter electrode (s) as the cathode . The basic principle of the electrodeposition coating, is water-soluble binder on the surface of the electrode precipitate switched to be painted (electric coagulation ) and so as to produce a closed, adhering paint film.

In 1963 the first anodic parts system was put into operation at Ford . The first body line was used by General Motors in 1967 . This technology came to Europe in 1969.

Due to the direction of the current , the ATL leads to an electrochemical anodic dissolution of the paintwork. This results in a high susceptibility to corrosion of the paintwork. That is why anodic dip painting only plays a subordinate role today. Instead, cathodic electrodeposition painting (KTL) is used.

With the introduction of the KTL in the automobile sector, the ATL has been replaced with a few exceptions. The advantages of corrosion protection speak in favor of KTL. The ATL has experienced a revival in recent years, as the old disadvantages have been reduced and there are now good paint systems. In contrast to KTL, ATL has the advantage of being more UV-resistant.

The KTL working with epoxy resin needs a proportion of 3 to 4% solvent to maintain its solution. Isocyanates and alcohols are currently used for this. Isocyanates will be banned in the EU from 2020. The ATL system is based on acrylic and is isocyanate-free.