Automotive: New materials for lightweight cars, EVs and components

In the automotive sector, less is more is quite a common phrase – with fewer component parts and a focus on lighter weight materials being used. As well, engineering plastics are also taking the realm of electric vehicles charging equipment.

Lightweighting a factor in seating

Automotive makers are replacing metal parts with lighter weight plastic parts for improved fuel economy and lower CO2 emissions.

German materials firm BASF and Toyota Motor North America Research & Development have achieved lightweighting success with the new 2021 Toyota Sienna. The vehicle, scheduled to launch later this year, features a reduced mass of the third row seat, with a 30% weight reduction and 15% cost savings vs the prior generation, where the third-row seat was comprised of 15 different steel components making it very heavy.

Automotive: New materials for lightweight cars, EVs and components

Traditionally, resin components for seating have had metal reinforcement, which can add more cost to the process. Toyota also wanted an injection moulded part that was a shoot-and-ship part – meaning it was made in one piece, without complex and costly post-processing. BASF used its 35% glass-reinforced and impact-modified PA6 grade Ultramid B3ZG7 CR, and its proprietary computer aided engineering (CAE) tool Ultrasim for development efforts.

Said Matt Parkinson, Manager Applications Development Engineering and Composite Technologies, BASF Performance Materials, of the seat design, “It is the first of its kind in the way it is designed without inserts as a fully injected seat back. One of the challenges was to ensure a high elongation and impact qualities for the crash requirements. At the same time, we focused on strength and stiffness because the seat also serves as a load floor.”

Commodity vs engineering plastics for parts

Automotive: New materials for lightweight cars, EVs and components

US firm ExxonMobil has introduced a new foamable PP grade as an easily and affordably processed sustainable solution for high volume applications, including food and beverage packaging, industrial packaging, building products and automotive parts. Achieve Advanced PP6302E1 is a high melt strength (HMS) grade that is said to improve product stiffness by up to 30%, compared to standard HMS PP foam, for significant cost reduction opportunities.

While foam applications have been dominated by amorphous polymers such as PS, PU and PVC, foamed PP is a relatively recent advancement having been introduced only about 20 years ago. Now, the commercial potential of foamable PP can be pursued and fully realised, says ExxonMobil.

Achieve Advanced PP6302E1 is said to be a viable alternative to PS foam (with accompanying VOC and monomer concerns), and can reportedly eliminate tradeoffs and set new standards for sustainable foamed PP parts by delivering value-in-use in a number of ways. For example, it is processable on existing PS foam lines with various blowing agents, reduces material use while delivering product integrity, and is recyclable where appropriate collection and recycling facilities exist.

In automotive parts (such as headliners, ducts, floor liners), the PP foamable grade delivers the stiffness that allows vehicle manufacturers to maintain performance properties while reducing weight and increasing fuel efficiency. The foam structure can also provide benefits such as heat insulation and sound dissipation.

Materials focusing on battery charging in EVs

With electric vehicles (EVs) a growing market, German speciality chemicals company Lanxess says it sees great potential for its technical thermoplastics in the charging infrastructure for electric mobility: for components of charging plugs and sockets, charging stations and wallboxes – in garages and carports, for example – as well as for components in inductive, wireless charging systems for high-voltage batteries.

Even though the level of standardisation in the field of electric mobility is currently still in progress in many areas, polyamides and polyesters offer a wide range of possibilities for applications in the area of battery charging with direct or alternating current.

Automotive: New materials for lightweight cars, EVs and components

Unreinforced materials are mainly used for charging plugs because they offer a high level of dimensional stability and surface quality, are impact resistant, and thus mechanically robust, and are also available as flameretardant compounds whenever they come into contact with live electronic parts. As an example, Lanxess’ halogen-free flame-retardant PA6 Durethan B30SFN30, in flammability tests conducted in accordance with the US standard UL 94, achieves a classification of V-0 with a test body thickness of 0.75 mm.

Given the ever-higher charging voltages and currents, heat-conductive thermoplastics for removing the heat that is generated are also becoming increasingly important. Mineral-based PA6 compounds Durethan BTC965FM30 and BTC77ZH3.0EF, which have high filler content, can be used in the vicinity of charging plugs. And despite the high filler content, the materials display elongation and processing characteristics.

Potential new applications for charging wallboxes include covers and structural components. As visible parts, covers have to be not only easily paintable and weathering- as well as UV-resistant, but also have a low tendency to warp. This requirements profile is met by Pocan C1203, for example, an unreinforced blend of PC/PBT.

Another current development trend is inductive and wireless charging of vehicle batteries. The flat floor and vehicle pads that are required here and accommodate – among other things – the inductive charging coils have to be constructed from materials that are not only fire-resistant and mechanically strong, but also have a low tendency to warp and exhibit high dielectric strength.

The materials also have to be light and weathering-resistant, with their properties remaining highly stable across a temperature range of -45 to +125°C. One material that can be used for floor plates is the glass-fibre and glass-ballreinforced PA6 Durethan BG30XFN01. It displays flow properties and is also strong and resistant to warpage.



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