Polyethylene film is a resinous material with thermoplastic
properties that is synthesized by inducing oxidation polymerization of ethylene gas. The degree of pressure used in
its manufacturing varies according to the density and melting point of the
virgin polymer resin being used. Most commonly, sheets of polyethylene film are
produced using a process known as blown film extrusion, in which the polymer
resin is melted to its flow point and then extruded through a die to produce a
tube of plastic. While the polyethylene is still supple, the tube is closed off
at one end and then blown to inflate and stretch the film into the desired
length and thickness. The thickness of polyethylene film can be as thin as
.0004 inch (10.16 microns).
The introduction of this film was considered groundbreaking in
terms of its application in the packaging industry. Specifically, it has proven
to be highly valuable in the flexible packaging market. In fact, it has
captured the majority of the plastic packaging segment, which primarily
consists of bags and wrapping material used for storage or to provide
protection from the environment. This includes plastic wrap to protect agricultural crops, as well
as ordinary kitchen wrap used to preserve food. Of course, polyethylene film is
also essential in the manufacturing of bags, from dry cleaning protective
covers to garbage and grocery bags.
One reason that polyethylene film dominates all other materials
formerly used in packaging is its ability to self-seal under controlled heat. Shrink wrap, for example, protects
items by literally shrinking around them to form a seal in response to the
application of heat. This ability makes this film ideal for use in making
tamper resistant packaging as well as to seal electrical wiring. In addition,
polyethylene sheets can be sewn or stapled together, or even bonded with glue.
Polyethylenefilm is also used extensively in the agricultural industry where it has many
applications. For one thing, it is used to protect crops and seeds from pests
and disease. This material also helps to prevent the escape of moisture and
heat.While most people are familiar with polyethylene film due to its
presence in many consumer products, it has a few lesser-known applications. In
fact, it is frequently used in building and construction. Aside from acting as
a tarpaulin to protect equipment and building
materials, it is also placed in the structural interior of buildings to prevent
the invasion of moisture. Polyethylene film also serves as a blanket to promote
the curing of concrete slabs.
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