Smart textiles prominent in the car of the future

Today’s car makers and their immediate (Tier 1) suppliers have a wide range of options with regard to the choice of interior materials. Besides the traditional use of textiles, leather, wood and metals, modern automotive interiors can be made from an increasing range of newer materials, such as thermoplastics, polyurethane (PU) foam, skins, lacquers, foils, elastomers and silicones.

Innovative automotive textiles of the future will have to offer enhanced functionalities, while at the same time being made from environmentally sustainable materials and offering lighter weight — all at the same or reduced costs. Meanwhile, suppliers are being challenged by sophisticated consumers, vehicles that are more intelligent and original equipment manufacturers (OEMs) needing to be even more integrated.

With current regulations, volatile fuel prices and increasing en­vironmental concerns, weight is becoming a significant cost issue for automobiles. Previously, lighter weight was in the “nice to have” category after other performance criteria had been evaluated.

Now, however, weight is becoming a core issue for automakers as it already has become in the aviation industry. In recent years, aircraft designers have worked continuously toward reducing weight through the introduction of new metals, carbon fibre composites and more efficient engines, while seeking to improve the acoustic levels both inside and outside the plane. In particular, the latest generation of aircraft, such as the Boeing 787 Dreamliner and Airbus A350, are designed to be lighter and more comfortable.

New concepts in lightweight and sustainable materials were key themes of Smart Interior Surfaces and Materials held in Frankfurt am Main, Germany, at the end of June 2009. The two-day conference was aimed at increasing perceived value and creating highly functional materials while cutting costs.

This 5th “international flagship event”, organised by the International Quality & Productivity Center (IQPC), brought together around 50 top-class delegates representing Tier 1 and Tier 2 automotive suppliers, OEMs, research institutes, and raw materials and chemicals suppliers.

With the automotive industry challenged to produce lighter vehicles that respond to unpredictable fuel prices with increas­ed efficiency, Tier 1 suppliers have taken the lead in offering alternatives.

Light Attitude

Following Happy Attitude and Premium Attitude, Light Attitude is the third in a series of concepts presented to the automotive sector by Faurecia. With the new concept, the company is challenging the industry to use innovative design concepts to re­duce weight and, therefore, low­er fuel consumption and carbon dioxide (CO2) output while still offering high value.

Launched in November 2008, Light Attitude features seats, cockpits, doors, acoustic packages, front-end modules and exhaust systems that can remove up to 30 kg from a vehicle’s mass, explained Design Studio Manager Thorsten Süß and Advanced Design Leader Julien Seiller of Faurecia Interior Systems, Germany.

Textile fabrics including nonwovens will play a major role in reducing automobile weight, and these are highlighted in the latest Faurecia concept. The Light Attitude interiors feature several uni­que applications, with fabrics re­placing many of the conventional hard-surface structures — even the centre console is made of fabric. The glove box lid, for example, becomes a sliding fabric cover and ventilation diffuses air through fabric rather than traditional hard vents.

A door module, partially trim­med with natural fibres, acts as an acoustic chamber, allowing the installation of smaller, lightweight speakers. A smart integrated docking station offers both weight reduction and new flexibility for incorporating and integrating ever-evolving media players and nomadic devices, such as I-pods. The new Light Attitude interiors are said to be 15-20% lighter than conventional interior systems overall.

The “sustainable comfort” seating system concept features a thin seat with an even thinner (175 mm) backrest made of an injection-moulded part with continuous glass-fibre inserts. This saves around 30 mm of interior space, allowing designers to reduce the overall length of the vehicle. The seat also comprises a 50% thinner cushion using thermoplastic PU, and an optimised, injection-moulded headrest that uses less foam and fabric.

Also in the Light Attitude acoustic package, the conventional dash insulator is replaced by recyclable, three-layer PU foam that can save 8 kg of weight.

“With the weight reduction from the 10 Light Attitude innovations, CO2 emission can be reduced by 2.2 g/km/car — or 1.15m tonnes of CO2 for 40 million cars each driving an average of 13 000 km a year,” Süß pointed out.

Tradition

Textiles have long been used in automobiles, mainly for historical reasons. Being open top, the first cars had seats made of leather or leather imitations. Wool, cotton and rayon were then used until synthetic fibres, such as nylon and polyester, became dominant in the second half of the 20th century.

As a material, textiles will have a small but important role to play in the automobiles of the 21st century. However, fabrics continue to have problems with dust, cleanability and ventilation, and there is a need for new, new high-tech textiles with enhanced functions that are, in particular, soil-repellent and abrasion-resistant.

In the car of the future, high-performance multifunctional textiles will act as systems, being fully integrated with the vehicle, said António Viera, chief executive officer of the Centre for Nanotechnology and Smart Materials (CENTI), Portugal. Such low-weight and low-cost materials will be flexible, biodegradable and ecologically friendly, offer real and proved benefits, and have smart layer functions.

Interior design

The first thing drivers or passengers see when they open the car door is the seat; this is also the point of direct contact with the vehicle. As a design element, textiles are widely used, particularly in luxury cars, to provide an image or “signature” of perceived value and quality.

Martin Bremer, Senior Manager Colour and Trim for Mercedes-Benz Cars at Daimler, Germany, said colour and trim design are used to create brand identity. “There is now more consumer desire for materials because engine technology has become too complicated to be a point of conversation,” he commented.

Describing a cab interior design approach for heavy and commercial vehicles, Giuseppe Bruno, Industrial Designer with medium and heavy commercial vehicles manufacturer Iveco, Italy, outlined the Iveco Engage concept, which looked at several issues, including style and materials. The interior is based on high-quality materials with high-tech features and innovative interfaces, such as hidden electrostatic trim panels.

Meanwhile, the Iveco Eurocargo interior concept, which is now in production, is based on increasing style while decreasing cost. This system features the use of a thermoplastic polyolefin elastomer compound to give a low gloss appearance, soft touch feeling, soundproof and safety features, as well as a metal-looking thermoplastic resin.

Bioplastics

Under the effects of the global financial crisis and “credit crunch”, consumers in developed economies have shifted their buying patterns away from sports-utility vehicles (SUVs) and other large “gas-guzzling” vehicles toward more fuel-efficient, lighter cars and hybrids (which use both petroleum and stored, rechargeable electricity for propulsion).

If this trend is a permanent one — and all the signs point to this being the case — cars of the future will also be cheaper, possibly using more recyclable materials such as bioplastics.

Bioplastics are biodegradable thermoplastic polymers made, at least in part, from non-fossil feedstocks. Their use could help reduce dependence on oil, widen the properties of existing plastics and help reduce CO2 emissions. (In a widely reported move, Japanese automaker Toyota plans to replace 20% of plastics used in cars with bioplastics.)

Dr Johannes Ganster, Head of the Department of Materials Development and Structure Characterisation at the Fraunhofer Institute for Applied Polymer Research IAP, Germany, described improving the properties of bioplastics with man-made cellulose fibres and nanoclay. When reinforced with rayon, for example, PLA, PHA, poly-3-hydroxybutyrate (PHB) and PHB/Ecoflex can produce bio-based and biodegradable composites with improved tensile strength, stiffness and impact strength, particularly at low temperatures. Meanwhile, cellulose acetate reinforced with nanoclay can be moulded without a plasticiser, offering improved strength, modulus and heat stability.

Alternatives

New automotive textile materials have to compete with established products and this poses certain trade-off risks, observed Dr Ralf Nörenberg, Head of the Competence Centre for Technical Textiles at BASF, Germany. He also noted a trend toward electro-conductive textiles (E-textiles) that have integrated electric or electronic functions via cables or wires sewn into the fabric, enabling opportunities for heating, seat occupation, interactive surfaces and ambient lighting.

Lenzing’s lyocell fibre Tencel, which is made from renewable cellulose resources, is being trialled as a car seat cover, reported Dr Friedrich Suchomel, Head of New Applications, Business Development and Innovation, Textile Fibres, at Lenzing, Austria.

The potential advantages of Tencel over polyester include im­proved moisture management without any electrostatic charging. Initial tests with a 30% Tencel blend have demonstrated higher shorter-term water va­pour ab­sorption compared with 100% polyester, while increasing the proportion of Tencel in a blend improves surface resistance in single jersey fabric. Further, a dosable Tencel fibre could be used for automotive interior parts.

In conjunction with Eurofoam, Lenzing has also developed a new PU foam that contains Tencel. Cellpur is said to absorb more water then standard PU foam, and could be used as lamination for car seat fabrics.

Meanwhile, Dr Wolfgang Neithardt, Manager Applications Engineering Tuft/Automotive at Freudenberg Vliesstoffe, Germany, proposed microfibre nonwovens made from Evolon as a highly effective, cost-competitive and lightweight material for automotive sound absorption.

Acoustic applications of Evolon include the headliner, dashboard, carpet backing, doors and the under-body heat shield. Using this materials, weight can be reduced by up to 40%, the absorption coefficient increased by up to 40%, cost reduced by up to 10% and thickness reduced by up to 50%, he told the delegates.

Function vs aesthetics

While the conference provided a number of alternative materials to consider, it perhaps had more of an emphasis on functions rather than aesthetics. Although technologists can make really interesting products, the automotive industry may need to look more through the eyes of a consumer, not from a trained technical viewpoint, to discover what the end-user really needs.

One OEM delegate pointed out that consumers today simply want value for money with a good, attractive exterior design, and better engine performance and electronic packaging, but are less willing to pay for luxurious interiors.

While automotive interiors can be a selling point, the industry can not focus solely on light weight — consumers may not be prepared to pay for this and the indications are that OEMs and Tier 1s will not pay suppliers for weight reduction.

From an article published in the August 2009 edition of MobileTex. For subscription details, click HERE