Formulating a genuinely new and better type of plastic isn't easy, and - some would argue - doing it in concert with General Motors Corp., makes it doubly hard.

Not only is GM tough on price, but it also is notoriously reluctant to give suppliers credit for their innovations. It is perhaps the last vestige of the infamous "not invented here" syndrome that nearly sank the U.S. auto industry in the 1970s. GM now is open to ideas from everywhere, but it still seems to struggle with the idea of publicly admitting it jointly developed something with somebody else.

But that's exactly what GM Research & Development did with Montell North America in December.

In a rare (for GM) joint press conference, GM and Montell announce they have developed a new family of thermoplastic olefins (TPOs) that offer significant benefits for interior and exterior automotive applications.

The former Chrysler Corp., which relies heavily on outside sources for components and technology, has made joint announcements with suppliers routine in recent years. Ford Motor Co. and numerous other automakers also have gotten into the act. But GM - bogged down by a history of keeping all information relating to its vendors under wraps - has been slow to jump on this bandwagon.

Nevertheless, GM recently heavily publicized a huge new contract with Alcan Aluminum Ltd. And GM officials at this latest event (at Montell's research center instead of GM's, no less) say they hope to publicize more innovative work they are doing with suppliers. The key catalyst, of course, is that these new revelations give GM much-needed good publicity: They show the automaker is working hard to develop lighter-weight, more fuel-efficient vehicles.

But the significance of the new materials technology should not be overshadowed. GM and Montell officials call this new plastics family "a major technological breakthrough" that yields numerous improvements in physical properties in addition to the ability to chop the weight of some plastic parts by 30%.

Instead of talc, mica or other conventional filler materials, these new TPOs use ultra-tiny "nanocomposites" to improve engineering characteristics of the base plastic resin. The nanocomposites used in this case are tiny flakes of clay much smaller than other reinforcing materials.

Unlike talc, mica or glass fibers, nano-composites can make plastic parts stiffer and more dimensionally stable without hurting low-temperature impact performance or making the surface finish wavy or bumpy.

The joint development program began in June 1997. Engineers at GM and Montell selected a family of natural materials called "smectite clays" from which the nanocomposites are derived. Texas-based Southern Clay Products Inc. is the supplier.

As little as 5% smectite clay provides stiffness characteristics equivalent to a 25% to 35% talc-filled material, says Theo Zwygers, Montell Automotive and Industrial Business Group technical director.

GM and Montell officials will not comment on when or where the new plastics might be used, but they showed off two prototype parts - a door panel and rear quarter panel - that were from GM's plastic-bodied Saturn cars. GM R&D department head Elio Eusebi says GM is validating the new plastic compound for a variety of interior and exterior applications, but neither GM nor Montell will say the new plastic will be used for panels on future Saturn cars.