In the fields of screen printing, painting, flexographic printing, in all the converting sectors, in the production of adhesive tapes and in lamination, there is a process without which there would be significant quality problems. Even packaging draws huge benefits from this process that is complementary to its actual manufacture.
This process is called Corona treatment.
The primary effect of the treatment is to “activate” the surface of a film, that is, to increase its surface energy. This increase in surface energy of the plastic film, metal, or paper, greatly improves the adhesion of inks, adhesives or other coatings on the surface of the film. It promotes the stabilization of one product over another.
To obtain good adhesion to materials that have a low surface energy, such as PP, PE, HDPE etc. a high voltage, high frequency electrical or corona discharge is created in close proximity to the part to be treated. This high energy corona discharge is attracted to the material severing the molecular bonds on the surface. These severed bonds are now free to attach to other particles that exist in the highly active corona discharge environment and so have a strong chemical attraction to inks, paint, coatings, adhesives etc. leading to significantly enhanced surface energy and therefore adhesion.
After the treatment, the result is a surface unchanged to the naked eye, but it is in fact much more receptive to inks, coatings and adhesives. “Improving the wettability*