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The last couple of years have witnessed an ever
increasing cost of polymers globally. Increasing competition from
low cost Asian processors coupled with higher polymer prices have
compelled the North American and European plastics processors to
look for ways and means to become more competitive. For this, one
of the important areas that these processors have worked upon is
to reduce manufacturing costs by increasing output.
Increasing outputs have caused a plethora of problems regarding
quality, rough surface finish, etc. with most of the commonly used
polymers like PE, PVC, etc. The industry has certainly benefited
from some of the processing aids being used for the last two decades.
Though reasonably effective, some of these processing aids could
not perform when output requirements increased significantly, and
have been replaced by more effective and improved versions of the
earlier products.
Generally the linear Polyethylenes like LLDPE and HDPE, as well
as the recently introduced Metallocene LLDPE grades are more prone
to formation of melt fracture. The earlier versions of fluroelastomers
used were required at higher dosage levels. Besides, some of them
caused the problem of higher conditioning time before they became
effective, translating into a higher wastage level. Their performance
was negatively affected when polymers contained other additives
like antiblocking agents or UV stabilizers. Both Dynenon and Atofina
have introduced product grades that are more efficient and more
tolerant to other additives. Processors making films from low MFR
LLDPE and HDPE have benefited significantly with the these newer
grades that are structurally more stable compared to the first generation
products.
Similarly, rigid PVC products have been benefited with the newer
Acrylic based polymer processing aids that have very high molecular
weights compared to the older versions. Most of the rigid PVC processors
presently use a blend of process aids having 1-2 million molecular
weights along with 3-6 million molecular weights. These high molecular
weight processing aids originally developed for stabilization of
foam cells are increasingly used for PVC profiles, sheets and bottles.
The mineral oils have been used in many polymers either to enhance
the lubricity or increase softness of products like TPE. Newer mineral
oil products of higher molecular weights that have been found more
efficient because of lower volatility, are more widely used in the
newer TPEs made from SBS, SEBS or PP/PE. Crompton has introduced
Hydrobrite 1000 mineral oil.
Dupont's Fluroguard oils have found an increasing usage where
abrasion resistance is more critical. Dupont also has Elvaloy AC
products that are copolymers of butyl, ethyl and methyl acrylates.
They enhance the dispersion of pigments in engineering polymers.
Vitro Co. in the form of viscosity modifier has specially developed
a very interesting product from naturally found Alumino sillicate
glass. This product is found to be very effective by the wire and
cable industry.
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