The fastness of screen printing ink
If not, you can only change the solvent type ink, solvent ink small tension, ink spreading, fast drying, adhesion will be much better, but the volatile harmful to human body and environment, and flammable and explosive, need to pay attention to a little.
If PVC can try to cloth, printing surface first corona treatment, the surface tension is higher (recommended to 55 - 60 dynes), and then look at whether there is improvement.
According to what you describe, it must be adhesion. Screen printing rarely water ink, because water ink in non absorbent substrate adhesion fastness is usually much worse than solvent based ink, plus screen ink layer is super thick, adhesion is more problematic.
