Many wide web flexo printers printing on films must use solvent based inks.
For the smaller printers, emission controls are extremely costly.
A significant amount of the solvent in the inks is often isopropyl alcohol
(IPA). IPA has a reactivity rating of 0.17; while acetone, a delisted VOC
is not much lower, at 0.16. Essentially, IPA is a relatively safe VOC and
it's use (if a water based ink is not an option) should be encouraged.
However, there is no incentive at this point and solvents with much higher
reactivity are treated equally to IPA by regulators. I've been told that
some ink manufacturers also could use IPA as a coupling agent in water based
inks (which have some amount of VOCs).
How can IPA use be encouraged and/or how can it be considered for delisting
by USEPA? This is an especially hot topic in Illinois, but has national
significance for all small flexo printers using IPA.
Doreen M. Monteleone, Ph.D.