A new technical paper presented by Tampere University of Technology at the 2008 TAPPI PLACE Conference in Portsmouth, Virginia, USA confirms atmospheric plasma surface treatment benefits.
The paper titled "The Influence of Atmospheric Plasma Treatment on Digital Print Quality of Extrusion Coated Paper" studies the influence of corona, flame and atmospheric plasma surface treatments compared relative to their effects on the surface properties of extrusion coating and, furthermore, on digital print quality.
The chart above is an excerpt from this paper which compares these processes relative to enhancing printability of toner to LDPE coated paperboard.
The specific conclusions of the study are as follows:
- Surface treatments clearly increase surface energy of PE-LD coated paperboard by oxidising its surface.
- Argon plasma is the most effective method based on the contact angle measurements.
- Also surface analysis with ESCA clearly shows the oxidising effect of all surface treatments. Plasma treatments are more effective than traditional flame and corona.
- Plasma treatments are generally speaking more effective compared to corona. Same or even higher effect can be achieved with 50% lower efficiency compared to corona and flame.
- All surface treatments evidently improve toner adhesion, which is very important in packaging applications. Plasma treated surfaces have the lowest rub-off values.
- The effects on print mottle are not yet advantageous. Some more development work is clearly needed with the treatment uniformity in order to improve print evenness. However, compared to corona and flame, plasma treatments are more uniform giving more even print with lower print mottle, and hence better visual quality.
As additional evidence mounts relative to the superior adhesion performance benefits of atmospheric plasma technology for specific applications, this author will make these application results known so the converting industry can leverage atmospheric plasma’s dynamic surface effects.