Surface treatment of powder-coated aluminium profiles

When bonding powder-coated aluminium profiles, adhesion complications can occur, which can be reduced by prior surface treatment. In this application report, Oliver Ehrengruber of Winterhalder Selbstklebetechnik GmbH reports on three different approaches that were tested to improve adhesion through surface activation and enable bonding of the powder-coated aluminum profile.

Application

The test dealt with a stand in which a fabric tape is applied to powder-coated aluminium profiles to reduce noise when folding. Due to a change in the formulation of the coating powder, the adhesion on the surface had decreased and the fabric tape no longer stuck as strongly as before.

Solution approaches

Three solution approaches were tested:

1. Wet chemical pre-treatment of the aluminium profiles with primer/adhesion promoter
2. Physical pre-treatment (flame treatment) with pyrosil gas
3. Physical pre-treatment (atmospheric pressure plasma) with the piezobrush® PZ3

Customer conclusion on 1.:

The wet chemical pre-treatment of the aluminium profiles with primer/adhesion promoter is ruled out due to the solvent load, which represents a health hazard, as well as possible soiling/streaks outside the bonding surface at the customer.

Customer conclusion on 2.:

The advantages of the physical pre-treatment, the so-called flame treatment, with pyrosil gas are the good increase of the surface energy and the simple application. However, the potential danger posed by the open gas flame in production has attracted negative attention.

Customer conclusion on 3.:

With the physical pre-treatment based on atmospheric pressure plasma with the piezobrush® PZ3, a very good increase in surface energy is possible. With the simple and safe application, this approach is the favorite of the test.

Conclusion

As a compact handheld plasma device, the piezobrush® PZ3 is the winner of this test due to its ease of use. The adhesion of the powder-coated aluminium profile was significantly improved and the bonding of the stand with the fabric tape was now perfectly possible. Without the use of chemicals or gases, any (health) hazard is eliminated. With the piezobrush PZ3, a safe and environmentally friendly surface treatment and thus an activation of the surface energy is possible.