Figure 1

The plastic surface is first activated through physical treatment (corona, plasma or flame).  A reactive photoinitiator is then grafted onto the polymer surface.  Thanks to the chemical/physical properties of the photoinitiator, the surface tension of the treated substrate is enhanced, achieving a typical average value of 48 - 52 dyne.cm, and wetting is improved. (Figure 1).

Moreover, grafting the photoinitiator onto the surface prevents it from migrating into the polymer mass.  For this reason, the treatment has practically unlimited storage stability, provided exposure to UV light is avoided.  Substrates treated with Prime IT can therefore be stored and subsequently printed without any further treatment.

In combination with UV technology, Prime IT ensures a superior performance to that of conventional processes.  The photoinitiator grafted using Prime IT technology actually reacts during polymerization, forming a chemical bond between ink and polymer surface.  In this way, satisfactory adhesion can be achieved on a number of critical substrates. (Figure 2)