Polypropylene makes a positive contribution to cutting fuel consumption and CO2 emissions

Lowering new vehicle CO₂ exhaust emissions has become the centrepiece of the auto industry's drive to ensure a sustainable future.  Key is that it is encouraging improvements in petrol and diesel engine performance but, although they are benefiting car owners, these enhancements will not be sufficient on their own to overcome the high bar set for emissions reduction by the European Union (120 grams per km by 2012 - although this target date may be revised).  Moreover, engine efficiency improvement has economic limits beyond which it is not practical to pursue further development even if it is technically feasible.

However, the one as yet unlimited avenue of vehicle weight reduction continues to be that of translating before mentioned metal produced parts into plastic components.  This conversion not only gives the advantage of weight reduction but also, with the appropriate choice of materials, offers the potential to lower system costs and, most importantly, it involves no part-performance compromises.

Borealis is recognised by automotive customers as market leader in this field through recent application innovations. Engineered polypropylene-based solutions are able to replace metal and other more expensive or less performing polymers to contribute to weight and cost savings for car makers.  Examples of this technology are evident in the variety of exterior, interior and under bonnet applications to which it has and continues to be applied.

A smart solution

Tasked with identifying the ideal polymer solution for body panels of the novel 'smart fortwo' micro car from the Daimler Group stable, lighter part-weight was just one of the enhancement criteria.  Others included excellent dimensional stability necessary to ensure consistent tight-tolerance part reproducibility, improved surface quality to provide for longer term paint adhesion and easy processing to maximise productivity.  Body panels of the previous version of the 'smart' car had been moulded in polycarbonate polybutylene terephtalate (PCPBT).

Borealis worked closely with customers, contributing engineering and simulation support, and met the challenge with Daplen™ ED230HP.  This 20% mineral filled elastomer modified polypropylene (PP) compound satisfied all specifications and delivered a significant 15% weight saving. 

An improved aim

Increased performance demands of the harsh under bonnet environment led VW to seek an alternative material to the glass fibre reinforced polyamide (PA) for the air intake manifolds (AIMs) on its 1.4i and 1.6i engines used in a variety of its car models.  In setting new performance parameters, VW and its Tier One added as an essential aspect of the brief that the replacement material should not require any significant change in part and tool design, nor modification of pre-existing specifications.

Borealis met these criteria with Xmod™ GB306SAF, a high performance 36% glass fibre reinforced PP compound developed specifically for tough under bonnet applications.  This Xmod PP grade was technically comparable with the material it replaced but delivered lower system cost as well as a 15% weight saving.

Targeted weight loss

When designing its new BMW 7-series, the OEM specifically set out to simplify production and reduce the weight of the model's back seat carrier.  Traditionally produced in steel and polyurethane, the new design was conceived as an all PP solution using Xmod™ GD302HP, a 30% customised short glass fibre reinforced PP.

The injection moulding process simplified manufacturing and required fewer secondary operations.  The changeover yielded substantially lower system costs and the replacement of steel with PP generated a weight saving of 35%, lowering overall vehicle weight by around 4kg.

A confirmed innovation

Recognising its unique capabilities, Xmod™ GB306SAF PP compound received the Frost & Sullivan 2010 Global New Product Innovation Award in the category 'Automotive Under The Hood Plastics', confirming the contribution it can make to significantly lower system and production costs for OEMs and Tier Ones.

The Frost & Sullivan Best Practices Research Team benchmarked the material against key competitors across a range of performance criteria, including innovation, value added features and benefits, and increased customer return on investment.

Robert Outram, Global Programme Manager, Transportation Chemicals, Frost & Sullivan said: "Lowering costs is essential for automotive manufacturers to remain competitive and achieve a positive margin.  The replacement of expensive engineering polymers with cheaper polyolefin-based polymers is thus highly desirable.  Borealis composite technology allows polypropylene based material to perform at similar technical specifications and in some instances better, than expensive engineering plastics."

A new automotive horizon

As an integral part of its ongoing search for solutions that benefit the industries it serves, Borealis is an active partner in the development of a visionary e-mobility system.  E-mobility is a concept of Teamobility AG, a new company focused on providing an answer to market needs for cost efficient lightweight road transport that is both versatile and sustainable. 

The new vehicle being developed by Teamobility will provide the basis of various models each performing different functions.  The involvement of Borealis' Mobility Team will centre on the development of material solutions for tailorable lightweight body panels and the first prototype vehicles are expected to be ready by the end of this year.