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The Indian extrusion processing sector is now becoming familiar
with using mLLDPE resins in producing mono and multi-layer structures
for food and industrial packaging.
In Europe and USA, reputed masterbatch suppliers servicing the industry
have focused on developing additive concentrates in mLLDPE as carrier,
in place of conventional LDPE or LLDPE. This has resulted in minimizing
any loss of strength, including dart and Izod impact and tear resistance
- besides retaining the excellent optical properties inherent in such
film resins.
Metallocene film resins are morphologically different because they
are more uniform in structure. This tends to retard migration of the
additives to the surface. Formulating these additives so that they
can migrate better to the surface is the answer. Optimized concentrates
with higher than usual 'active ingredient loadings' overcome the migration
problem.
One of the usual problems encountered with the low softening point
or heat seal temperature of mLLDPE and some other low density high
performance resins is that they tend to have a tacky surface. Their
COF value is high and as a result, they adhere to other films as well
as to themselves and to metal surfaces of the production equipment.
Their aim is to decrease the COF, reducing the sticking tendency and
this can be done by utilizing high 'active ingredient' masterbatches
based on mLLDPE as carrier resin. The masterbatch is strongly suggested
for use in multi-layer film applications where mLLDPE or a plastomer
is used as the skin or heat seal layer. Examples include fresh produce
packaging and meat wraps that require very high gloss, low haze and
very high clarity.
(Courtesy - Plastics Technology)
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