Automotive interiors graded on air quality

Although the quality of outside air remains a concern for environmental groups, at least one group is closely monitoring interior air quality, specifically car interiors, 50% of which are made of plastics, according to the Ecology Center (Ann Arbor, MI).

In a presentation during the Society of Plastics Engineers (SPE; Brookfield, CT) Global Plastics Environmental Conference (GPEC; March 6-7, Orlando), Claudette Juska of the nonprofit Ecology Center said the growing importance of what goes into a car interior is relative to the increasing amount of time drivers spend in their vehicles, with the current average at 1.5 hr/day: more time than is spent outside. Those periods are times when drivers can be exposed to off-gassing of materials and volatile organic compounds (VOCs) that the Ecology Center is now tracking. Of particular interest are phthalates in polyvinyl chloride (PVC) components, which the Center says can off-gas, and the bioaccumulation of certain flame retardants, specifically DBDE (deca brominated diphenyl ether), which it says can degrade into chemicals banned by automakers.

In April the center published a Consumer Guide to Toxic Chemicals in Cars (www.healthycar.org), releasing the results of a study where x-ray fluorescent spectrometry was used to give an elemental readout of all the materials in a car. More than 200 cars were sampled, with the material makeup of over 2400 parts, including consoles, carpets, trim, headliners, dashboards, seat bases, gear shifters, tested.

Of the group the Ecology Center tested, they found that 79% didn’t have chlorine, 57% didn’t have bromine, and 38% didn’t have halogens, according to Juska. Cars rated favorable included the Acura TSX, Honda Odyssey, Chevy Cobalt, and Cadillac CTS. In addition to the Ecology Center’s efforts, Japan’s Ministry of Health and independent test institutes like Oeko-Tex (Zürich, Switzerland) and TÃœV Rheinland Group (Cologne, Germany) are creating standards for car interiors.

TÃœV has certified four Ford vehicles for adequately limiting VOCs in their interiors, and Toyota and Honda are working toward approval, with Honda saying it wants to be PVC free and Toyota setting a goal to lower VOCs by 2010.

The Ecology Center also releases an annual Automotive Plastics Report Card (see MPW November 2005 World Tour for more), based on sustainable materials application, including recycled content and biobased polymers, with the latest coming in November 2006. The report covers the eight largest car sellers in the U.S., encompassing 90% of the autos sold in America. The grades were Toyota (C+), Ford (C), Honda (C), DaimlerChrysler (D+), General Motors (D), Hyundai (D), Nissan (D), and Volkswagen (D-). “The gap is growing between the leaders and the laggards,” Juska said, “but of course, the leaders still only have Cs.” The Ecology Center’s goals for the industry are to eliminate halogenated flame retardants, design with 95% recyclable plastics, and use 50% recycled or biobased resins by 2015.

Materials suppliers eyeing huge pie

Car manufacturers are busily taking steps to improve their products’ environmental footprints, with one result an ongoing increase in the amount of materials based on renewable resources in many standard vehicles.

Carmakers’ demands are leading to a surge of innovation from some of the market’s leading suppliers, including plastics, coatings, and chemicals supplier BASF (Leverkusen, Germany). During an automotive customer event in March, BASF’s Volker Warzelhahn, senior VP for thermoplastic R&D at the supplier, asked, “Can we make bioplastics from petrochemicals?” His answer—yes—is revealed in a product now at market launch, in which some of the molecular chains of standard polybutylene terephthalate (PBT) are replaced with ones from the supplier’s Ecoflex biodegradable plastic. He says the firm also is working on development of polyamide based on renewable resource materials, specifically sugars.

BASF also is developing a ‘genuine’ bioplastic, poly-hydroxobutyrat (PHB), fermented from starches. He says PHB/Ecoflex blends approach polypropylene in nearly all mechanical properties, but allows that PP’s density is as yet much lower. Ecoflex is a biodegradable plastic based on 1.4-butanediol and dicarbonic acids, adipic acid, and terephthalic acid, which debuted at the K show in 1998.

The pace of development of bioplastics needs to continue, of course, as highlighted at a meeting organized in February between Europe’s Federation of Reinforced Plastics and representatives of European automotive OEMs and Tier One suppliers. The attendees came to the conclusion that the automotive industry offers a great future to renewable resource materials—both fibers and plastics based on renewable resources—but that significant work needs to be done before the latter make it into significant numbers of commercial vehicles.

Fibers, on the other hand, are already seeing broad use because they offer advantages beyond simply being ‘green.’ No surprise that cost and ability to work new materials into manufacturing trump sustainability as the issues of greatest importance, according to the meeting’s organizers, but design also plays a major role. Here natural fibers score well, with their low weight compared to most alternatives, as well as their relative availability, reason enough for a number of car OEMs to use them.

Of course, most environmentally friendly plastics developments still involve more traditional materials, just better employed. Weight reduction through metal replacement remains a proven means to improve fuel economy. Plastics supplier Lanxess (Leverkusen, Germany) worked with L&L Products Europe (formerly Core Products; Molsheim, France) to develop injection molded structural carriers which are used in conjunction with a high-density structural foam developed by L&L Products and integrated into the lower part of a car’s A-post, lower and bottom parts of the B-post, and in the cross member of the rear axle, all important locations in case of a crash. The nine inserts not only increase the load resistance of a car’s body, and help to absorb some of the energy in a crash, but also bring weight savings of about 12 kg per vehicle on the Renault C4 Picasso, according to Lanxess.

And in the lab phase at BASF is work on a polyurethane (PUR) encapsulation project in which PUR is used to cover a car’s motor, so that less heat escapes and a car can more quickly return to operating temperature between short starts and stops. Warzelhahn notes this is one of a number of projects ongoing to make better use of the heat generated by a car’s motor.

Bioplastic to biodiesel

Using vegetable oil and an engineered enzyme, researchers have created a bioplastic that they say is more durable than standard polyethylene, but after use can be quickly broken down into liquid biodiesel fuel for use in transportation. The development captured the attention of the U.S. military, which experiences fuel shortages and solid waste surpluses in stationary operating positions, and was given a $2.34 million grant by the Defense Advanced Research Projects Agency to commercialize it.

The research was undertaken Richard Gross, director at Polytechnic University’s (Brooklyn, NY) National Science Foundation Center for Biocatalysis and Bioprocessing of Molecules. Biotech firm DNA 2.0 assisted in the development of enzymes that synthesize and break down the polymer into biodiesel after use. The grant will be used to find a more-efficient, lower-cost process to make the bioplastic and break it down after use.

“I don’t think the builder, in all honesty, cares whether it’s green or not. They want what’s good for them with respect to installation and application. But if the end consumer wants it, then it matters, and I think the end consumer is concerned with being green, and that movement has grown a bit in the industry.” Robert Bulla, president of Commercial Plastic Composites (Newan, GA), which specializes in spindles, railings, caps and other B&C applications.