PCT Engineered Comparison of UV and EB Technology for Printing and Packaging Applications User Manual
Comparison of uv and eb technology for printing, And packaging applications, Tech n ical p ape r
SEPTEMBER/OCTOBER 2008 RADTECH REPORT 27
Tech
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ical P
ape
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Comparison of UV and EB
Technology for Printing
and Packaging Applications
By Stephen C. Lapin
U
V/EB curing technology for
inks, coatings and laminating
adhesives has become well
established in certain segments of the
packaging industry—including folding
cartons, labels and multiwall bags.
There is also growing interest in UV/EB
technology for flexible packaging.
1
The
growth in UV/EB applications is due, in
part, from the inherent advantages over
solvent- and water-based materials.
The solvent in conventional inks,
coatings and adhesives functions
simply as the “carrier” for the “solids”
high energy required to remove water
from the solids portion of the formula.
This high-energy requirement for water
is illustrated by comparing the heat of
vaporization to some common solvents
2
:
water = 540 calories/gram
toluene = 88
heptane = 76
The generation of energy needed to
operate the driers to remove water
results in significant CO
2
emissions. In
addition, most water-based materials
do contain some solvents to aid the
formation of the polymer film upon
drying the ink, coating or adhesive. Also,
in many cases, water-based materials do
not have the resistance or appearance
properties to match higher performance
solvent- or UV/EB-based materials.
In spite of the clear advantages of
UV/EB technology over solvent and
water-based technology, there is often
some confusion as to whether UV or
EB is a better choice. A clear
understanding of the differences
between UV and EB can facilitate a
selection of which technology is best
suited to the end-use application.
UV and EB Energy
Considerations
There are some fundamental
differences between UV and EB energy
that provide the foundation for
understanding the technologies. The
smallest “bit” of UV energy is the
photon that is known to have both
particle and wave-like characteristics.
A clear understanding of the differences between
UV and EB can facilitate a selection of which
technology is best suited to the end-use application.
portion of the material. In most cases,
solvent emissions are handled by
thermal oxidation which produces
greenhouse gas (CO
2
). Solvents are
highly refined materials derived from
fossil hydrocarbon sources. It is quite
wasteful to use such a high-value
material for such a low-value temporary
function. Solvent-based materials are
old technology that is clearly out of
step with a sustainable future.
At first glance, water-based inks,
coatings and adhesives would appear
to be an excellent choice from an
environmental perspective. Water is a
relatively plentiful, low-cost and
environmentally friendly carrier. The
main disadvantage with water is the
º