Slip additive used in plastic film and bags

Slip additive used in plastic film and bags
What is slip and how does it work in manufacturing plastic
film and bags.

Slip is an organic chemical that is added to the blend
during film extrusion process to modify the coefficient of
friction (COF). COF is a measurement of the amount of
friction between two surfaces as they begin to slide and as
they continue to drag against one another. The amount of
energy it takes to put an object in motion is always
greater than the amount of energy that it takes to keep it
moving while it is in motion.

Although there are a number of chemicals that are used to
modify the COF the two main ones used in Polyethylene and
Polypropylene are Erucamide (which is considered a slow
bloom) and Oleamide(which is a fast bloom). The materials
are sometimes called primary amides. Slip is a very
efficient molecule it has been added to a plastic film in
very low concentrations typically 500 to 1500 parts per
million (PPM).The slip additive can be let down at the
levels of 1 to 3% by weight in blending while extruding the
plastic film. Slip molecules are very low in molecular
weight as compared to the polymer in which they are used.
These molecules are somewhat incompatible because of their
nature. This means the material is bi-polar and has one end
that has a positive charge and the other has a neutral
charge. This incompatibility causes the molecule to migrate
referred to as bloom through the polymer to the surface of
the plastic film.

The more slip that migrates on the surface the lower the
COF and the more slippery the plastic film becomes. The COF
relates to packaging because the substrates used to package
objects always come in contact with other surfaces or
themselves. As most packaging operations are very high
speed, COF plays a very large role. The packaging material
must have just the right COF in order to track properly on
the packaging machines. If a material is too slippery the
film will not track properly and may cause issues such as
bad sealing or cause a powder substance that builds up on
the tracking rolls which will cause packaging failures. If
a material becomes to sticky it can have the opposite
effect. It may not allow the film to un-wind properly and
cause web brakes or other tracking problems. Either
scenario can shut a packaging line down.

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David Banig has been in the Flexographic printing industry
for 32 years and has had various patents along with hands
on experience. If you are looking for someone to improve
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