the increased demands, production was started in
this country in 1944.
After the war more and more uses were found
for polyethylene Now the packaging industry
must vie for its share of polyethylene flake pro
duction against high frequency electrical insula
tion, squeeze bottles, molded products, water pipe
and a host of other interesting applications.
WHAT IS POLYETHYLENE
Polyethylene is the name given one group of
thermoplastics. The polyethylenes are hydro-car
bon resins resulting from the polymerization of
ethylene. Under extreme high pressures, liquid
ethylene, a petroleum product, forms into waxy
flakes or polyethylene resins. Polyethylene is
produced in film form by extrusion through the
use of heat and pressure alone. The outstanding
qualities of polyethylene include flexibility and
toughness over a wide range of temperatures, un
usually good resistance to water and penetration
by moisture, resistance to chemical action, and
unique electrical properties. It is one of the
lightest of all plastics.
HOW IT IS MADE
Practically all of the polyethylene film made in
the United States is produced by means of a hot
melt thermo-plastic extruder which consists of an
electrically-heated cylinder within which there is
a revolving screw to generate pressure and advance
the melted resin through the cylinder and die.