Lighter, stronger and more economical, specialty fabrics drive innovations in automotive applications.
By Holly O’Dell
Since the first automobiles appeared on American streets more than 100 years ago, fabrics have had important functions in car manufacturing—most obviously in upholstery. But the use of specialty fabrics extends far beyond seating, and many textiles used in vehicles are not as obvious.
Fabrics are used in carpeting and protective floor mats; the interior ceiling, called the headliner; seat belts; magazine or map pockets on the backs of the front seats; interior door panels; trunk liners; steering wheel and gear shift covers; convertible tops; and the shelf underneath the back window in cars—and that’s just what the eye can see. Still other materials are used as protective barriers and for thermal control.
In total, a mid-sized car will use about 44 pounds of textiles, according to www.fibre2fashion.com. For all of those fabrics manufacturers must meet safety and performance standards required by automotive OEMs and the government—and please the consumer.
A long history
Seat design alone has necessitated a number of fabric innovations. Cotton, wool, mohair and leather were favorite materials in the first vehicles; as seat design changed, the fabrics covering them did too. “We went from stiff vinyl upholstered bench seats in the 1950s to bucket seats that ergonomically fit the body,” explains Nancy Powell, an associate professor at the College of Textiles at North Carolina State University, Raleigh, N.C. “With those seats you had to use materials that would stretch to fit the form and wouldn’t wear out when they were trimmed around that shape.”
When cars and trucks incorporated more glass, the interior fabrics had to meet higher light-fastness standards, and with the advent of minivans and SUVs, textiles had to be more rugged for these vehicles. Heated and air-cooled seats, too, required fabrics that could work equally well with this relatively new technology.
Vehicle interiors are made primarily of polyester for many reasons. Not only is it cost effective and easily available, but the fabric meets the high performance standards, such as durability, required by the automotive industry. For instance, fabrics need to withstand sitting under the blazing desert sun or below-zero temperatures and still tolerate moisture buildup in warm, humid climates. Durability also means that a driver or passenger can get in and out of the car repeatedly without damaging or dulling the seat fabric.
Automobile manufacturers have added soil and stain resistance to the list of performance standards for fabrics because consumers are spending more time in their cars, including eating on the go. Comfort and aesthetics also play a role. Woven and knit polyester fabrics can showcase lustrous or matte finishes, while a nonwoven polyester can look and feel like suede. Customers also want the fabric to have a soft hand and be colorfast.
To continually and consistently meet these needs, automotive textile manufacturers have focused their R & D efforts on improving aesthetics and exceeding performance standards in their offerings. Sage Automotive Interiors of Greenville, S.C. is driving innovation with its YES Essentials® fabric, used most recently in the 2011 Hyundai Sonata. Not only does the fabric inhibit mold and bacteria growth, it also improves air quality by eliminating odors—even those caused by VOCs. Furthermore, Sage’s “repel and release” technology allows spilled drinks to bead up and be wiped away, and YES Essentials has anti-static properties too.
In addition to important factors such as durability, car fabric manufacturers must meet rigorous safety standards set by the U.S. government in conjunction with the automotive industry. Such is the case with safety restraints. “Seat belts need to outlive the car,” says Woody Dew, president of Tennessee Webbing in Knoxville. “You can find 20-year-old vehicles in the junkyard where the whole seat belt assembly still performs flawlessly.”
The seat belts are made of 100 percent high-tenacity polyester. “It is the perfect fiber for this application because it doesn’t change,” Dew notes. “It doesn’t shrink or stretch over time.”
From a safety standpoint, seat belts have to meet a certain percentage of elongation in the webbing, which is the stretch of the webbing on impact. “This prevents the material from cutting into your skin or organs and minimizing the damage to the body in an impact situation,” Dew explains. Additional safety requirements include a high breaking strength and self-extinguishing flammability standards.
Seat belts also feature UV inhibitors and a slick, siliconelike finish—both of which are integrated into the fabric during the dye process. Aesthetics are important too. “The car companies want their own signature on their safety restraints,” Dew says. “They may request that their webbing have a particular weave pattern. It is purely cosmetic and has no impact on a seat belt’s safety.”
What consumers want
Consumers influence many of the choices available in both current and future automotive interior fabrics, and they have very high expectations, Powell says. “We can go on the Internet and experiment with placing a certain color in a car’s interior. That’s why when we go to buy a vehicle we may not want the one that’s in the dealer’s showroom. We want to order something that’s customized to our preferences.”
As such, OEMs and textile manufacturers perform significant research to understand the end user’s lifestyle. Sage Automotive, for one, took this approach when introducing FXC®, a fabric designed to stand up to adventure. “The roots of FXC came from a research project we had done that indicated consumers’ desires to have a more functional material,” says Julie Jacobs, design manager for Sage Automotive. Sage then partnered with Honda, which wanted to enable its adventure-loving customers to hose down the interiors of its Element® vehicle. The result: a seating fabric that is waterproof, comfortable, stain repellent and resists mildew and fungus.
Automotive OEMs and fabric makers need to find a balance, though, according to Powell. “Because automotive product developers are working so far in advance of new vehicle introduction, you don’t want to be too far reaching. But if you are too slow bringing it to market, then the consumer will think it looks dated or old.”
Car manufacturers have put millions of dollars into researching and developing hybrid and electric vehicles that emit fewer pollutants into the environment—and fabrics are along for the ride. “We have to create materials that are just as safe and strong while reducing the weight of the vehicle to get better gas mileage,” Powell says.
That is exactly what BMW is doing. In 2013, the Munich, Germany-based car manufacturer will introduce the Megacity Vehicle (MCV), its volume-produced electric car with a passenger cell made from carbon fiber reinforced plastic (CFRP). Made from polyacrylic fibers that are carbonized by exposing them to heat, then spun into fibers, the fibers are woven into a CFRP fabric, which provides the actual raw material used by the motor industry.
“The car companies cut them to size for the required component and lay them in a mold,” explains BMW spokesman Tobias Hahn. “A resin system is then injected to create the required shape, and the component is hardened.”
CFRP counts many benefits, including its high strength and rigidity combined with low weight. “It is around 50 percent lighter than high-tensile steels and around 30 percent lighter than aluminum,” Hahn says. “CFRP is also highly resistant to corrosion.”
The material’s light weight adds to MCV’s fuel efficiency. The car will be 772 lbs. (350 kg) lighter than electrical vehicles of comparable size. “The weight advantage directly translates into a more efficient use of energy,” Hahn notes. “In other words, the MCV will achieve better mileage per kilowatt hour of stored battery power.”
Gearing up for the future
BMW’s Megacity Vehicle illustrates where the automotive future is heading: sustainability. “We are always looking for new materials that rely on a less energy-intensive process in the making of the fiber and yarn,” says Jacobs of Sage’s green efforts, adding that the company has researched alternative materials such as corn and bamboo. “But we certainly have a lot of engineering and safety requirements to meet, and we know that polyester can do that.”
Recycling interior fabric is another area that Sage Automotive is exploring. The practice would involve removing the seat cover after its life, grinding it up and creating new materials with it. “The adhesive used to bond these materials together is also an area that we should consider,” says Jacobs, because of the need to find more earth-friendly adhesives and new technology for attaching them to the seating. To achieve sustainable results, OEMs and textile manufacturers need to put their heads together, Jacobs says. Of interest to Sage is developing new fabric constructions that would allow for suspension seating rather than the traditional seat built with thick foams and springs.
New demands for personal transportation in emerging economies are resulting in significant growth in global automotive markets. This increase in total number of vehicles in the world’s cities and roads also affects consumption of resources and environmental concerns, such as emissions, Powell says.
The automotive industry is starting to address the big question of what happens to a vehicle at the end of its life. In the European Union, legislation requires that the vehicles and the materials within can be recycled, reused or disposed of safely. In this regard, the U.S. lags behind. “Given the economic pressures that OEMs are under, they say their customers are not willing to pay a premium for greener materials,” Powell says. “Unless the government or market demands it, it will be difficult to commit to such a major change.”
Other big ideas for the future include creating new fibers and finishing technology to produce a different touch and look, as well as using smart seating fabric as part of the onboard electronics. At NCSU, for example, 80 researchers across the university’s colleges are studying transportation-related topics, including employing lighter weight composite.
“We need to be as innovative in the second hundred years [of vehicle interiors] as we have in the first,” Powell says. “Textiles have a tremendous role to play in that, and they could have an impact not only on economic development but also sustainability. We need to continue creating products that the consumer wants.”