Lamination refers to the process of bonding two or more layers of material together using an adhesive, thus endowing the original materials with new functionalities. This technique is often employed with materials such as films, aluminum foil, paper, and non-woven fabrics.

The corona treatment in the lamination process is used to improve the surface of plastic films. It activates the surface and increases the surface energy. Due to such treatment, the film's surface wetting tension is enhanced, what increases the film's polarity, raises the surface tension, and augments the affinity for adhesives. As a result, the bond strength between the laminated films is improved.

The effectiveness of corona treatment is contingent upon several critical factors, including the voltage applied to the electrodes and the precise distance between the electrodes and the corona treatment roller. Under high-magnification microscopy, the surface of a corona-treated film reveals a distinctly uneven and coarse texture. This topographical alteration is advantageous for adhesive applications, as it promotes superior wetting and fosters a more robust bond between surfaces.

However, corona treatment should be moderate, as a higher intensity is not necessarily better. Over-treatment may lead to the corona effect on the reverse side of the film, which could cause issues such as ink transfer during printing or layer transfer during aluminum plating and adhesive application.