Topic: improve adhesion of the adhesive, plasma instead of primer, pre-treatment of sealings
Volkswagen: primer out - plasma in
Source: Volkswagen AG
Automobile construction as an example: in order to improve the adhesion of the
adhesive, the final points of the caoutchouk sealing are pre-treated by Openair® plasma.
The reasons for the application of Openair® plasma were obvious for us. For our „Golf IV“, we developed an adhesive-bonded additional door-sealing for the avoidance of wind sounds. This self-adhesive sealing made of EPDM-caoutchouk should be fastened at the ends with additional glue dots by a MS adhesive. This caoutchouk has to be pre-treated in order to improve the adhesive’s adhesion. The conventional method is the manual application of a priming coat – a method that is no longer applied by Volkswagen nowadays.
We dicided for Plasmatreat’s in-line technology: If these sealings
are pre-treated by Openair® plasma directly before the adhesive is
applied, this method replaces several process steps. This highly
efficient pre-treatment rendered superfluous not only the normally
necessary pre-cleaning of the adherent, but also the application of
solvent-containing primer coats precedent to the agglutination.
Positive consequences for Volkswagen were: no expiry dates of the
primer have to be considered, no solvent emissions and no logistic
constraints with the supply.
Volkswagen counts on „sturdy processes“. They are the precondition
of an equally high quality of our products. The Plasmatreat method has
the big advantage of reproducibility, if the installation’s parameters
are firmly monitored. As official in charge of adhesives and sealing
agents in process engineering, in this regard I see Openair® plasma as
a very safe and environmentally friendly pre-treatment method.
Michael Stege
Process engineering
VOLKSWAGEN AG
