is it possible to print on polypropylene so that the printed text will be resistant to boiling?
Try asking Nazdar. We use their SS series thermoset inks, maybe they have something that will UV cure and be heat resistant.
Having worked too long in the baby industry I have this one down.
Normally you have to flame treat the PP surface that you are going to print right before it goes into the silscreening machine. And yes UV cured inks make all of the difference.
A little history - PP plastic was formulated to hold paints and inks so we are trying to decorate something that was made not to be decorated. Aren’t we stubborn