Plastic grows in auto manufacturing

In 40 years, the use of lightweight plastics in US automobiles grew from an average of 60lb (27kg) per vehicle to approximately 330lb (150kg) per vehicle in 2007.

"More than 50% of a typical vehicle's volume is composed of plastics and polymer composites, but these materials only account for approximately 10% of total vehicle weight," says Keith Christman, the ACC's managing director, plastics markets.

Meanwhile, in emerging countries where new capacity is being built, "we see companies [taking another look] at the value of plastics versus traditional materials when the system costs are similar," says Greg Adams, vice president, automotive, at US-based SABIC Innovative Plastics (IP).
SABIC IP has supplied polymer material to US auto firm General Motors' forthcoming all-electric Volt, and the QarmaQ from South Korea's Hyundai.

The chassis tends to be a high-weight section of a vehicle, and "the challenge the plastic industry will have is with the chassis," says Dagmar van Heur, vice president at Styron Automotive, a division of US-based Dow Chemical.
In March, Dow agreed to sell its Styron business to compatriot private equity firm Bain Capital for $1.63bn.

Additionally, the large battery pack needed by electric vehicles "is a huge opportunity," says van Heur. "These cars will need to reduce weight to get any type of range that the end-consumer would like to see."

Plastic grows in auto manufacturing

SABIC IP sees the industry ready to finally make a change to using polycarbonate (PC) for windows. "The technology has been in development for over 10 years, and is ready for mass adoption," says Adams. "The weight can be reduced by up to 50% where current windows are heavy above the car's center of gravity."

In 2010, the US Corporate Average Fuel Economy (CAFE) standards were made more stringent. The average fuel economy for cars must improve by 37% from the current 27.5 mpg, where it has been since 1990, to 37.8 mpg by 2016. The truck standard has increased by 23% from 23.5 mpg to 28.8 mpg.

According to Styron, a 10% reduction in vehicle weight - about 200lb - offers 5-7% fuel savings, provided the vehicle's powertrain is also downsized. If the powertrain is not reduced, a 3-4% fuel saving is achieved. Either way, for each pound of reduced weight, carbon dioxide emissions are reduced by 25.3lb over the life of the vehicle.

Cars have not become lighter over the past 10 to 20 years because weight has been added via more exotic electronics and bigger engines. "But with CAFE laws, they are going to have to stop doing that," says Baron. "They are going to have to get weight out of the car, and leave it out."

Regarding the new CAFE regulations, "there is a desire to improve fuel efficiency through using lightweight materials, but there is some discussion that the lighter the vehicle, the less safe it is," and that is also the broader public perception, notes Harrison.

"So the US Department of Transportation [DOT] and the National Highway Traffic Safety Administration [NHTSA] find themselves with competing agendas - one to provide the safest vehicle possible, and the other to provide the most efficient vehicle possible. And the two may not be complementary."

CAFE will influence manufacturers to reduce weight, but along with the cost, "the big issue with plastics and composites is ensuring comparable safety," says James deVries, chairman of the automotive composite consortium for the US Council of Automotive Research (USCAR). "Metal is considered the strongest material, and thus considered the safest."