Why is Corona so special for PP-Cast-Film?
Not all film materials can be treated equally well. Thus, the corona treatment of PP plays a special role. This means enormous generator performance at high production speeds. But this also increases the risk of undesired backside treatment due to thermal overload of the film. This places particularly high demands on the design of a corona treatment plant for PP films.
Stainless-steel tubular electrodes improve the treatment
Stainless steel tubular electrodes offer advantages in the treatment of Cast-PP over aluminium multi-electrodes. They take care of
- Higher treatment performance without backside effect
- Higher surface energy at the same specific power (efficiency)
- Lower thermal load on the treated material
- Higher long-term stability of pre-treatment
- Less energy use
- Higher production security
- Longer shelf life
- Lower costs
OPP and BOPP
Stretching lines stretch CPP (Cast PP) to OPP (oriented PP) and BOPP (biaxially oriented PP). Although the thermal load capacity of the material increases, at the same time the treatability deteriorates. Each stretch generally increases the necessary dose for equivalent treatment results substantially.
Another peculiarity is that with longitudinal stretching, the speed increases and, in the case of transverse stretching, the working width in the stretch ratio. Therefore, particularly large generator powers are necessary to activate BOPP film sufficiently for printing or laminating. At the same time, the Corona Station must be able to translate these tremendous benefits into surface effects. AFS systems meet these requirements.