Emissions reduction, lightweighting and structural rigidity are the cornerstones for materials development in the automotive sector. Globally, R&D initiatives are underway to create polymer compounds using innovative additives and composites, which help achieve the aforementioned objectives. As a leader in specialty chemicals, Lanxess has been actively involved in the manufacturing of high-performance materials for vehicles. Auto Tech Review met Thomas Babl, Head of Technical Marketing & Engineering Services, Asia Pacific, Business Unit HPM, Lanxess Hong Kong Limited, to discuss the concept of sustainable mobility and weight reduction, and how a material specialist addresses key industry concerns.
Lanxess has multiple product portfolios, ranging from interior and exterior body parts, to rubber compounds for tyres. With the use of high-tech plastics, plastic and metal hybrids, and fibre-reinforced composite materials, auto makers are fast replacing metal parts with light yet strong and safe plastics, which reduce the weight of car parts by 30 % or more.
Alternative drivetrain concepts and autonomous cars of the future demand material innovations, some of which can also be successfully implemented in current generation cars to verify their viability for the future. The need of the hour is to develop halogen-free, flame-retardant plastics with electrical insulation properties for higher passenger and pedestrian safety. Good resistance to sustained high temperatures of 180º C and above is a must, coupled with high stress cracking resistance.
LIGHTWEIGHTING FOR VEHICLES
Polyamides (PA) and polybutylene terephthalates (PBT) are versatile materials and in the context of modern automobiles, are used in electronic systems, air and fluid lines, and weight-saving bodywork components. High-tech plastics from Lanxess that are based on PA and PBT, which represent a lighter-weight plastic alternative to metals such as steel or aluminium, fulfil the requirements of commercial vehicles, passenger cars and two-wheelers. Lanxess markets the two plastic product lines under the name Durethan and Pocan. ‘In the automobile industry, Pocan and Durethan are increasingly replacing metals as a weight-saving alternative, especially under the hood, where materials must stand up to heat, aggressive chemicals and continual vibration,’ said Babl.
These materials can be used to directly mould many functional parts, such as fastening elements, guides and contact surfaces, when injection moulding is used to manufacture vehicle components. The materials can currently be found in engine bearings, door structures and seat cross-members, among other areas. Judging from the raw materials, Durethan provides a high-degree of mechanical strength and stiffness, good electrical insulating properties, improved heat, chemical and wear resistance, better frictional and dry-running properties, noise absorption and vibration damping abilities. Lanxess has also developed a new polyamide 6 grade, which is ultra-tough at extremely low temperatures. It can be used to manufacture fuel tanks that are lighter and more cost-effective for natural gas-powered cars. A tank system based on the new material developed as a case study by Lanxess has already proven itself to be ready for series production. The result is a plastic tank that weighs around 75 % less than a steel tank and cuts total vehicle weight by 4 to 7 %.
Amongst the multitude of factors impacting emissions and fuel economy, rolling resistance considerably influences a vehicle’s fuel consumption and CO2 emissions. The higher the resistance, the more energy is required to move the vehicle. Mass is a key factor in determining the rolling, gradient and acceleration resistance that act on a vehicle. Lightweight design is, therefore, a logical solution. ‘Savings of a relatively modest 100 kg in vehicle weight enables enormous emissions reduction that as a rule of thumb equate to 11.65 g less CO2 per kilometre travelled,’ said Babl.
Lanxess offers lightweight materials and innovative amalgamation and compounding concepts that are applicable to numerous vehicle parts in car body engineering, under the hood/drivetrain, as well as in exterior and interior applications. Weight saving is elevated further through smart material combinations, such as plastic/metal or plastic/composite material hybrid technology, which has already been applied to many car components like pedal systems, roof frames, front end structures, structural inserts and cross car beams.
THE WAY FORWARD
Key advancements in materials development will occur in the area of electric and hybrid vehicles, and will also include improved and mature battery technology to solve the current limitations of excessive weight and limited operating range. Lanxess is enabling weight reduction initiatives in cars through numerous metal replacement modules. Lightweight solutions are mainly applied to the car body, chassis, drivetrain, interior and electronics. The company’s Durethan and Tepex composite sheets are applied to thermoplastic engine oil pans, CNG gas tank liners, cross car beams, front end structures, brake pedals, steering rods, airbag housings, battery system carriers, airbags, car body inserts and structural body frames.
In the future, advanced engineering thermoplastic compounds will help improve crash performance via better pedestrian protection systems that OEMs will be able to engineer into their cars. They will also enhance the reliability of electronic and mechanical safety systems like airbags, even under the influence of harsh environmental conditions. Innovative plastic compounds may also provide electric shielding, to protect electronic assistance systems from interference, which will help as cars become increasingly connected to the Internet.
TEXT: Anwesh Koley