Polypropylene (PP) is extensively used in
both interior as well exterior applications
of automobiles, gaining in application because
of environmental pressures on recycling of
automobile plastic parts. Since PP is the
leading material used in automobiles, car
manufacturers tend to replace parts made from
other plastics also with those manufactured
from PP. However, the shortcoming of PP parts
is the ease with which scratches can take
place on them. Bumper fascia and other exterior
claddings are two major applications of PP
in the automobile. Typically elastomeric PP
(PP modified with elastomer) is used for these
automotive parts. Due to their softness their
abrasion as well scratch resistance are not
adequate and these parts tend to get easily
scratched.
Ciba, the global leader in the additives
for polymers has recently introduced a new
additive called Irgasurf SR 100 that when
blended at 2-3 % level in PP enhances the
scratch resistance significantly. A product
with 3% addition improves scratch performance
at least by 30%. Ciba has not disclosed the
nature of this additive and is therefore difficult
to understand its performance. The other additive
that is normally used to improve scratch resistance
of PP is high molecular weight silicone. This
product is available from the leading supplier
of silicone oil (Dow). The comparative performance
of this new additive from Ciba with silicone
oil needs to be understood before accepting
this new additive.