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12 SEPTEMBER 2008 | PBEI
Palletizing. How easy are the bags to load on a pallet and
how stable are they once palletized?
Discharge. Discharging the contents of the bags quickly,
easily, cleanly, and safely corresponds to bag type, but it also
depends on the discharge methods your customers use.
Printing. The bag must give you enough room to print
all the necessary information on it.
Reuse. Sometimes bags are returned for reuse and sometimes
they can be recycled. Woven PP bags are best-suited for
reuse.
Batch inclusive capability. With the correct packaging
materials, the bag and its contents can enter a process cham-
Figure 2
A net-weight form-fill-seal bagging machine.
ber, such as a reaction vessel, together. This eliminates packaging
waste and reduces costs.
FIBCs. In some applications, such as packaging engineering
plastics, the use of FIBCs is increasing. They are an attractive
alternative to smaller bags because they
Are easy to discharge using a vacuum pneumatic conveyor
Use less packaging material than smaller bags to hold a
given quantity of material
Remain stable when stacked
Fit snuggly in standard 6- and 12-meter-long containers
Can be reused
See Figure 1.
IBCs. Rigid IBCs are a good alternative
when the contents require
strong protection or a highly stable,
stackable package that only a rigid
container can provide.
Ready-made bags. PE and woven
PP bags are simple packages and easy
to transport manually. You can also
use the weight of the bag’s contents
(typically 25 kilograms) as the dosing
unit and thus eliminate the need
for batch weighing. Furthermore,
bag-filling operations can be highly
automated to maximize capacity.
FFS bags. In the petrochemical
industry, FFS bags, made from tubestock,
continue to gain acceptance and
may now dominate. Of all the 25-kilogram
bags available, FFS bags—made
from 120-micron-thick, side-gusseted
material—are the most economical.
Typically, they are co-extruded in two
layers. Usually, 80 percent is low-density
polyethylene (LDPE), and 20 percent
is linear low-density polyethylene
(LLDPE). Some FFS bags are made
with 50 percent of each material. Coextruded
bags withstand temperatures
to 93°C, so they are well suited to handling
petrochemicals that must be
packaged while they are still warm, a
development that is common due to
changes in production methods.
FFS technology
When evaluating whether an
FFS bagging system is right for your
operation, consider
Bagging rate (number of bags per
hour)