WARREN, MICH. - General Motors Corp. is launching the first commercial automotive application for a nanocomposite thermoplastic olefin this fall.
The part, an optional step-assist for vans, is a relatively minor contract, accounting for fewer than 10,000 2002-model GMC Safari and Chevrolet Astro vans. But it represents a breakthrough that could spur further growth of nanocomposites in multiple industries.
``This is just the first of several applications,'' Alan I. Taub, executive director of science for Detroit-based GM's Research and Development group, said during a press introduction Aug. 28 in Warren.
Already the company has tested its use for everything from body cladding to fenders and rear lift-gate doors, producing both painted and nonpainted surfaces. The resin is less prone to expand and contract in severe weather, which will lead to smaller gaps between panels, and a better overall look to the vehicle.
Its lighter weight and improved performance, meanwhile, also show promise for interior substrates, replacing either metal or existing heavier composites in everything from door panels to air-bag brackets.
``The growth [pattern] on this is going to take off like a hockey stick,'' said Bill Windscheif, global business vice president for Basell Polyolefins, which has worked with GM in developing the new material.
In a Principia Partners study published before the GM and Basell announcement, analysts predicted automakers could use about 20 million pounds of polyolefin nanocomposites by 2005, with substantial growth to follow, perhaps growing to 200 million pounds by 2010.
Landing a production contract, even on a limited basis for now, is a major development, said Principia Partners director Jim Morton.
``It's not trivial,'' he said in an Aug. 29 telephone interview. ``Once a technology or material class has a good foothold, the [use] can blow up very fast.''
Like thermoplastic composites already in use, the new TPO uses a filler material to provide additional strength and stiffness. But unlike a glass- or talc-filled system, the nanocomposite uses minute particles of a clay additive, called smectite, supplied by Southern Clay Products Inc.
The filler is only one-millionth of a millimeter thick, and 5 grams of smectite would cover a football field, said Robert G. Briell, senior scientist for Gonzales, Texas-based Southern Clay.
As a result, the TPO nanocomposite may have as little as 2.5 percent of the fill material vs. 20 percent or more in a conventional composite, Windscheif noted.
In actual production parts, that can mean weight savings of 20 percent, which should improve fuel efficiency for consumers, Taub said.
Manufacturers, meanwhile, will see improved material flow, which means faster cycle times and fewer defects.
Promise around corner
Even greater promise is ``just around the corner,'' Windscheif said, as researchers look to combine the structural properties of the nanocomposite with the growing studies of in-mold coloring. The auto industry can reduce costs greatly if it can produce parts complete with a Class A surface that do not require painting. So far, it has proved difficult to turn out the metallic colors preferred by automakers at a cost they are willing to pay.
The TPO nanocomposite, Windscheif said, holds additional promise because it has less fill material than other external plastic panels. That gives the companies greater flexibility to bring in additives to create a desired color without compromising the raw material.
``Obviously we're not at that stage today, but that is the direction this technology is going,'' he said. ``If you think about it, if you're able to reduce the filler content and retain the stiffness, that opens up all kinds of things that you can do with nanocomposite TPOs.''
Several companies have been trying to produce nanocomposites in other materials since the nylon breakthrough nearly 10 years ago. GM's drive to introduce the TPO blend will fuel that research, said industry consultant Karl Kamena of Midland, Mich.-based OmniTech International Ltd.
``One of the motivations in [GM] getting involved is to get people working seriously on nanocomposites,'' he said. ``It will really start rolling from here.''
It also will provide a buffer to research dollars that cost-conscious companies might otherwise have dropped, Morton said. Firms that already have put millions of dollars into research needed a sign that there is a real commercial application ready and waiting for product.
``This is a very good thing for this to occur in the industry at this time,'' he said. ``They needed something like this. They needed a boost in this technology, especially with the way the economy is now.''
GM signed on to nanocomposite TPO research in 1998, teaming up with Basell predecessor Montell Polyolefins to develop the first commercial family of the material.
This fall's van application will cost the same as parts made from more-conventional composites, he said. Likewise, the parts can be made using existing tooling and presses.
The companies jointly have exclusive rights to producing parts with it for a ``number of years,'' Taub said.
Basell can ramp up production quickly once GM gives its approval to use the nanocomposite on more parts, Windscheif said. Likewise, molder Blackhawk Automotive Plastics Inc. of Salem, Ohio, is ready to begin production once it has the OK, said Clifford W. Croley, president and chief executive officer.
The step-assist part is fairly complex to mold, Croley noted, so it will give Blackhawk and GM plenty of experience for an initial material launch.
``If you can prove it out in a low volume with a difficult part, then we'll be ready to go with anything that comes our way next,'' he said.
The automaker is taking it slow for now, though, making certain all the bugs are worked out of the material before taking on a bigger piece of the vehicle.
``This is the right [program] because with a new material, you get some surprises,'' Taub said. ``You have to walk first, and then you run.''