Stretch Wrap

Blown vs. Cast Stretch Wrap

Stretch wrap, also commonly referred to as stretch film is a highly elastic plastic film that is used to secure items.  The stretchable nature of the film causes it to contract once no pressure is on the film to cause it to stretch.  There are several different kinds of stretch wrap including: hand stretch wrap, extended core stretch wrap, machine stretch wrap and static dissipative wrap.  Each kind of stretch wrap is best used on specific tasks and products.

Stretch wrap is usually made out of linear low-density polyethylene (LLDPE).  The resulting film created is highly stretchable and puncture resistant.  Most stretch wrap has approximately 500% of stretch before reaching the breaking point, but it is common for the stretch to not reach over 300% when in actual use.  Properties to consider when purchasing stretch wrap are tear resistance, cling, break strength and static discharge.

There are two common methods for producing stretch wrap: blown and cast.  Blown stretch wrap uses a melted resin that is air cooled.  Blown stretch wrap is of a higher quality, but it is more expensive due to the slower manufacturing process.  Cast stretch wrap has the film fed over cooling rollers, making the cooling process significantly faster and thus the finished product less expensive.  The use to which you will put the stretch wrap will ultimately determine which kind of film you purchases.  If a less expensive cast stretch film will work, why pay more for blown film?  On the other hand, if you have a load that is worth thousands of dollars then quibbling over pennies seems a little pointless.