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Polyamides have an important role in the automotive
sector. In fact, the growth of Polyamides is generally driven by
growth in the automotive sector. The overall economic slow down
of the last couple of years in USA, Europe and Japan; the major
markets for automobiles, has adversely affected the market for Polyamides.
To stimulate their growth, the major global producers
of Polyamides have been developing newer products to increasingly
develop more applications, particularly in the under-hood section.
Polyamides with improved colours help in achieving better aesthetics
in addition to the functional requirements of mechanical properties
at higher temperatures. The newer grades of Polyamide 6 and 66 have
been developed, having the higher toughness as well as stiffness
at the elevated temperatures. These grades also bring newer functionality
like laser weldability and resistance to glycols. Generally the
glass fiber reinforcement is required to enhance the mechanical
properties that are essential for automotive applications. Traditionally
black parts from glass reinforced Polyamides used in the automotive
sectors cannot prevent hiding of weld lines etc. To achieve better
aesthetics, external painting is required, leading to an increase
in cost. The newer grades, having better flow characteristics, without
adversely impacting mechanical properties have specifically developed
to prevent formation of such weld lines. Higher flow and better
rheology help in achieving better productivity. These new high flow
grades are now available from all the major international players
like BASF, Bayer, DSM and Rhodia. This has opened up the application
of engine covers in many European cars like Volkswagen or Citroen.
The improved aesthetics of the engine cover enhances the visual
appeal of the automobiles. The improved flow also is responsible
for developing those applications that have more complex designs
like that of long engine cooling fan assembly that integrates blower
wheels and other air-transport components.
For thick extruded sheet (up to 6 mm thickness), Bayer has developed
an easy flow Polyamide 6 with higher melt strength. The thicker
sheets are aimed at the engine shrouds, underbody panels and sound
shields. The higher melt strength helps in achieving more uniform
thickness distribution of these thermoformed parts.
The high flow Polyamide 66 grades with glass fiber reinforcements
can be used in place of the thermoset materials for a very large
rocker panel part. In fact, if found successful, they can replace
Aluminum which has a higher market share for this part. Mercedes-Benz
has already replaced this part in 35% glass reinforced Polyamide
66. In fact most of the major European car manufacturers have adopted
Polyamide 66 for this part. US car makers are seriously evaluating
this option.
There is a space limit in the engine compartment. The conventional
vibration welding causes problems of sensitive electronics for the
Air-intake manifolds. The newer grades of Polyamide 6 with laser
welding ability from Bayer have helped in achieving more compact
designs.
The improved surface appearance or availability in the other colours
than black would definitely increase the share of Polyamides in
the automotive sectors. Higher temperature resistance provided by
the newer grades would also help in achieving more penetration in
the engine compartments, that are becoming more compact and sophisticated.
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