Polymers have often an hydrophobic and soft surface with a somewhat unappealing look and a low surface tension, which is harmful for adhesion of inks, paints and other coating, adhesive joining, decoration, scratch resistance.
For many plastic parts it is necessary to modify the surface properties to improve wettability, reactivity, adhesion of decoration and technical coatings, and to adapt the surface characteristics to the customer's requirements.
The following figure 'Surface-modification-causes-and-effects' quotes some of the reasons leading to surface treatments and some of the effects of surface modifications.
Decoration and printing allow to:
1. Differentiate productions from those of competitors
2. Differentiate parts for safety applications
3. Cut costs of coloured parts that can be mass produced in a neutral colour and then decorated in the various desired colours or aspects
4. Produce a special effect determined by styling or design.
Protection is obtained by creation of a barrier between the polymer and the environment.