Plasma UV painting systems
A single step pre painting process that improves the bonding of the paint to materials that are normally difficult to coat, or where uniformity of bonding is an issue. Thus reducing time and scrape. It replaces process such as sandblasting and coating with solvent primers for example when bonding rubber to metal.
This includes several sub process, but as they are completed without the need for ventilating the chamber they are quick and controlled.
Ultra fine cleaning first removes any contamination and provides a homogeneous surface. The transition to the second stage is immediate. A reactive aerosol is introduced to the chamber which the plasma decomposes to its molecular groups, these deposit homogeneously on to the cleaned substrate where they remain ready to form a permanent bond with the coating (paint, printing ink or adhesive).
The aerosol is selected to provide functional groups that are physically and chemically adapted to those of the coating. The primer coating is extremely thin (in the nano meter range) but uniform.
Plasma curing of UV paints provides a cost saving, fast, energy efficient process with a low environmental impact.
High levels of UV light are emitted when electrons in plasma return from their excited state to their basic state. Depending on the process gas used this light has a high UV content which can be used for curing UV coatings. The intensity of the UV light can be optimised by the excitation frequency.
A minute amount of IR radiation is also present in comparison to the levels of UV light this has a positive effect on the paint curing. This is especially true with dual cure systems which contain a solvent that needs to be removed.
UV paint curing in a plasma atmosphere differs from that achieved by conventional UV radiators, the fact that it is not a uni directional light source gives it an attractive advantage in that the coated component completely bathed in UV light, thus enabling the coated areas that would normally be in the shade with a directional light source to harden as well. This aspect is of utmost importance for the processing of mono-cure systems.
Dual-cure systems still contain a certain fraction of solvents which must be removed from the plasma chamber. A cold trap can be used to recover them completely, preventing encumbrances on the VOC balance of the painting plant.
A continuous automated in line production where components are pre treated printed / painted and cured simaltainiously.