Document Sample

What is meant when someone mentions flexible plastic sheeting ? What kinds of
flexible plastic sheeting is there? Are there different types? In its simplest terms, the
main difference between the different types of plastic is the way their cellular
structure, or molecules bond with each other, and how tightly they are formed.
Who is the most flexible of them all?
  Linear Low Density Polyethylene (LLDPE) is the most flexible of the plastic
sheeting films. LLDPE is blended form of LDPE where the film has much more
flexibility, tensile strength, and more conformability. It is more pliable and softer.
LLDPE is used for pond liners or blended into other films to give them more
flexibility and extra strength. LLDPE is used for films that need a tremendous amount
of strength to absorb impacts while not tearing or puncturing. An example of this is a
carpet plastic film that adheres to the carpet. It is strong enough to withstand foot
traffic, even from stiletto high heels! The molecules all line up and strongly hold
together as the film is stretched. The most common thickness range is from 0.5 mil to
40 mil in flexible plastic sheeting.
Who is the most common of them all?
Low Density Polyethylene (LDPE) is the most common type of plastic sheeting. It is
very flexible, most often from 0.5 mil thick to about 40 mil in flexible sheeting forms.
Due to its flexibility is conforms well to a variety of surfaces. The downside is that
this LDPE is not as strong or dense as some other types of plastic sheeting. It is not
nearly as puncture resistant either. LDPE is used quite widely in construction,
agriculture, surface protection applications, covers of all sorts, tarps and much more.
Who is least commonly used of them all?
Medium Density Polyethylene (MDPE) is the least commonly used form of
polyethylene for flexible plastic sheeting. Its positive attributes is that it is stronger
than LDPE and has a little more chemical resistant. It has a tighter cell structure
making it more tear and puncture resistant. When pond liners are manufactured they
are often made with MDPE and blended with LDPE or LLDPE to achieve a strong yet
flexible pond liner.
Who is the toughest of them all?
  High Density Polyethylene (HDPE, aka HD), has the distinction of being the
strongest, toughest, most chemical resistant and least flexible of the four types of
flexible plastic sheeting referenced in this article. HDPE is also the most UV resistant-
holding up to the harsh rays of the sun without needing UV additive packages.
HDPEs strength comes from its tight cell structure that makes it very difficult for
other molecules to pass through its structure on a microscopic level. When
applications call for very large liners such as pond liners, HDPE is the most easily
seamed or sewn together. Used industrially, the thickness range from 12 mils to100
mil thick. HDPE is used as secondary containment liners for oil tanks, and most
industrial ponds and canal liners where chemical resistance is needed.