Home' FLEXO iQ : June 2015 Contents trapping of the paste inks is well established, which allows curing all
colors with a single EB system at the end of the press. Advantages of
web o set package printing include low plate costs, high print quality
and low ink usage. EB inks have a consistent high degree of cure,
which makes them attractive for food packaging applications.
Duncan: e primary advantage for UV over water or solvent for
exo is the 99.9 percent elimination of volatile organic compounds
(VOCs) and air emissions. EB exo is still a delicate process, since
there can be no interstation curing, but yet exography requires inks
to be pretty dry before being imprinted upon. Much progress has been
made here, but EB exo is still very sensitive.
McCusker: UV and LED curing o ers printers energy savings, im-
proved productivity and an environmentally conscious solution. UV
and LED allows customers to process thermally sensitive material at
increased line speeds, along with enhancing the product with more
scu and chemical resistance.
FLEXO iQ: For printers considering UV/EB/curing equipment, what
do they need to be aware of? Is now a good time to make the move?
Lapin: A er many years of development, EB exo inks have been
improved and are performing well on optimized CI press equipment.
EB exo may be a great choice for certain applications, but may not
be a t for all package printing scenarios. Printers should consult with
ink, press and equipment suppliers as they consider EB exo printing
McCusker: Printers need to be aware of mechanical and electrical re-
quirements and overall additional facility requirements when adding
UV equipment to their existing presses. Now is a good time to invest,
and the market certainly thinks so, too: e demand for UV cured
products is growing, due to the product improvements and high line
FLEXO iQ: From an ink standpoint, what do printers need to know?
Duncan: e biggest point is that the inks undergo a nearly complete
chemical change upon curing. In solvent or water based processes,
there is evaporation, but no real
chemical change occurs in the
ink---the same molecules in the
wet ink are in the dried ink. With
UV/EB, most of the chemicals in
the wet ink do not exist at all in
the dried ink. ey are chemically
changed into high molecular
weight polymers by the curing
process. is is a big help, both
for the minimizing of emissions
and for the minimizing of any
chemical migration potential.
FLEXO iQ: What are some key speci cations of features to be mindful
of when comparing UV/EB/curing equipment/inks?
Lapin: For EB equipment, operating costs including electrical power
and nitrogen usage may be an important consideration. EB curing
is inherently a low heat process; however, a system incorporating a
chill roll to support the web in front of the beam may be an important
consideration for printing on lms. A maintenance item for mid web
and wide web EB equipment is changing of window foils. Easy access
to the window and a single foil system versus a two foil system may be
McCusker: e printer needs to review the nal label requirements,
and get the answers to a number of questions:
• Does the nal customer need higher gloss, mechanical durability
or chemical resistance?
• Does their press have the necessary mechanical spacing and
electrical interface for UV equipment?
• Will the customer be processing lms or paper labels?
• Finally, does the printer have the capital budget?
FLEXO iQ: Is UV/EB/curing equipment more prevalent in narrow
web or wide web printing?
Lapin: UV is more prevalent in narrow web, while EB is more widely
used in wider web package printing.
Duncan: UV is much more prevalent in narrow web printing. ere
is some wide web UV exo, but the heat coming from UV lamps can
cause some thermal distortion of some plastic substrates, which can
cause registration issues. All of the EB exo presses that I know about
are in the range of 1-m. wide or less.
McCusker: UV equipment is being used on narrow web exo presses,
as well as wide web CI presses.
FLEXO iQ: What speci c applications (labels, sleeves, exible
packaging, etc.) account for the greatest percentages of UV/EB/curing?
Lapin: For EB, the largest printing applications are folding cartons,
shrink sleeve printing, pre
laminated dry food packets and
multiwall bags. ere are only a
few lm exible packaging EB
printing installations. A more
well established application for
EB in exible packaging is the
use of curable clear coatings over
conventional exo inks.
FLEXO iQ: How do the various
printing disciplines rank in UV/
Many existing conventional flexo
presses can be converted to UV.
Driers have to be removed and lamp
systems must be installed, but that
is not too hard."
-- Don Duncan, Wiko Color Corp.
ISSUE 2 | FLEXO iQ 2015 25
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