INSIGHT: Composites to replace more materials in autos

Author: Al Greenwood


By Al Greenwood

HOUSTON (ICIS)--Huntsman and other companies are making rapid advances in composites by reducing the cure times of their resins and removing the barriers that kept them out of mass-produced automobiles.

Composites are attractive to automobile makers because they can reduce the weight of their vehicles and increase their fuel efficiency.

These materials can reduce the weight of vehicles by 50%, which would translate into fuel savings of 25%, said Craig Blue, director of energy efficiency and renewable energy programmes at the Oak Ridge National Laboratory, the largest science and energy lab of the US Department of Energy.

Composites are made of reinforcing agents and resins. The reinforcing agent can be carbon or glass fibre. The resin can be a thermoplastic or a thermosetting resin.

These thermosets can be epoxy resins, polyurethanes or unsaturated polyester resins (UPRs).

The thermoset producers have sought to bring cure times for their resins down to three minutes or less for high-volume applications, Blue said.

In the past couple of years, Huntsman has made advances that achieve that benchmark. Those three minutes are important because anything longer can make the resins impractical for many high-volume parts.

Huntsman has been reducing cure times by adapting the chemistry and formulations of its resin systems, said Scott Wright, president of Huntsman's Advanced Materials segment.

These systems include more than just the resins. They also include catalysts and curing agents. Huntsman makes amine curing agents, formulates polyurethane systems and produces epoxy resins, so it has working knowledge of both the resins, the curing agents and the formulations.

By adjusting chemistries and formulations, Huntsman can do more than just reduce cure times. It can also make its resin systems amenable to different processing technologies. These different technologies can also reduce time and costs.

"As you look forward, companies are looking even further down the road to things like wet pressing," Blue said.

In all, the cost and efficiency of making composite automobile parts have improved by several orders of magnitude, making them more attractive to automobile producers.

"It's really an exciting development in the last 12 months," Wright said. "We're not finished yet."

Huntsman displayed the advances it has made in composites during a press tour of its technology centre in The Woodlands near Houston.

The composite materials were not in prototypes or concepts. They were in actual automobiles that are being sold.

A 2017 BMW i3 electric automobile on display has a composite passenger-cell made of carbon fibre and Huntsman's epoxy resin.

The photo below illustrates the composite part.

This is the composite part from the BMW i3

(Image source: Al Greenwood)

Because of the strength of the carbon-fibre passenger cell, the vehicle lacked the support pillars that are typically found between seats of a sedan, said Kourtlen Thomas, a product specialist at BMW. The automaker calls such specialists geniuses, and they know many of the details of their vehicles.

The composites helped reduce the weight of the vehicle to 2,700 lb or a little more than a tonne, Thomas said. These weight savings brought the range of the vehicle to 118-215 miles (190-346 km), depending on the battery package of the automobile. Prices for the vehicle start at $42,000

Huntsman also displayed the Zenos E10 sports car, which has a polyurethane-based chassis that the company developed with Bright Lite Structures.

The polyurethane technology, Huntsman's VITROX HC 98010 Polyol with SUPRASEC 9801 Isocyanate, was among the three finalists for this year's Polyurethane Innovation Award, given during the Polyurethanes Technical Conference of the Center for the Polyurethanes Industry.

Because of the specifications needed for the chassis of the Zenos E10, the cure time for the polyurethane was eight minutes. For other applications, it can be even shorter, at less than three minutes. The price for the Zenos E10 starts at £26,995.

The photo below shows the sports car.

Zenos E10 sports car

(Image source: Al Greenwood)

While Huntsman and other companies make advances on resins, other groups are cutting costs for carbon fibre, the other component for several types of composites.

Carbon fibre is made from polyacrylonitrile (PAN). Oak Ridge is developing carbon fibre from textile-based PAN instead of costlier high-end PAN, Blue said. Production costs are less than half that for traditional manufacturing methods for carbon fibre.

Last month, LeMond Composites reached a licensing agreement to bring the technology to the market.

Both Blue and Wright of Huntsman expect automakers to use increasing amounts of composites in the next five to 10 years.

However, don't expect all-composite vehicles any time soon.

Wright expects adoption to be gradual. As automobile producers introduce new platforms, the vehicles will use increasing amounts of composites.

Blue said, "The thing to keep in mind is it's going to be a multi-material solution." For example, the use of a composite in one part of a vehicle could allow automakers to use less steel in another part.

In fact, companies cannot substitute materials in isolation. Automakers view their vehicles as a system and not as a collection of individual parts. New materials require different paint, different joining technology and different finishing technology.

Supply chains also need to evolve, Blue said. While the composite industry has been around for decades, it is still relatively small. "So a high volume vehicle, if you put just a modest amount of carbon fibre, it would completely eat up world supply," he said.

The automotive industry is a major global consumer of petrochemicals which contributes more than a third of the raw material costs of an average vehicle. ICIS tracks the movement of petrochemical raw material costs in auto production both globally and regionally with the weighted ICIS Basket of Automotive Petrochemicals (IBAP).

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