DETROIT - The race to replace PVC in auto interiors is revving up, with more options in both materials and manufacturing.
Thermoplastic polyolefins still are receiving extensive attention, but urethane-based skins for instrument panels and other large parts also are on the increase.
Meanwhile, alternative production methods for the materials also are growing, with a European company winning contracts for a spray polyurethane technique and Japan's Infiniti luxury group debuting a vehicle with the first slush molded TPO skin.
``There are different classes of approaches to [interior] skins,'' said consultant Robert Eller, president of Robert Eller Associates Inc. of Akron, Ohio, who spoke about production and material options during the Auto Interiors Show, held May 15-17 in Detroit.
Material suppliers and processors are working out the bugs in a variety of systems to provide alternatives to the vinyl coatings still used in the bulk of vehicles produced worldwide.
PVC is falling out of favor as automakers seek skins that can provide a seamless air-bag cover as well as eliminate fogging and cracking problems. The world's biggest automaker, General Motors Corp., has a goal to eliminate vinyl from interiors by 2004.
There are two primary methods for interior skin production: vacuum forming and slush molding - also called casting. PVC works well with either system, but TPOs typically are vacuum formed, and PU usually is slush molded, Eller said.
The type of skin used sometimes depends on the process automakers prefer, he added.
TPOs are the skin of choice on a variety of vehicles, including Ford Motor Co.'s Focus and the GM Buick division's first sport utility vehicle, the Rendezvous.
``There doesn't seem to be anything standing in the way of TPO,'' said Tim Jackson, vice president of sales and marketing-interiors for Haartz Corp., which is providing the material for the Rendezvous, produced by Intertec Systems.
Haartz also has won contracts for a series of upcoming vehicles, with both door and instrument panels in one unspecified 2003-model vehicle and two more 2004-model instrument panels.
During the past three years, the company has spent $25 million to expand the TPO production line at its Acton, Mass., headquarters. Haartz is prepared to expand as demand for the product increases, Jackson said.
``We're really in the infancy of making TPO systems as cost-effective as they can be,'' he said. ``We see prices continuing to come down the lines.''
TPO is a relatively familiar product, Eller noted, with resins available from a mix of companies and a lower cost than other polymer alternatives. But it is not perfect, he added. The vacuum forming process makes it difficult to produce a rich grain pattern. TPOs also are glossy, making them more prone to scratches and mars and requiring processors to apply extra coatings to improve the look - which increases the overall price. Urethane, on the other hand, is more expensive and fewer material suppliers provide it, but it has a low-gloss, soft-touch look that consumers tell automakers they want, and it does not have the same styling issues as TPOs.
Textron Automotive Co. Inc. has produced PU skins since the 1998 model year for a variety of vehicles, including DaimlerChrysler AG's Chrysler Concorde, 300M and Dodge Intrepid.
``Frankly, we've got no ax to grind one way or another,'' said Jeff Rose, vice president of technology for Troy, Mich.-based Textron Automotive. ``We've got contracts for interiors with PVC, with TPO, with TPU.''
PU, though, is finding a niche in midlevel and higher-level vehicles, in which automakers want to marry a richer-looking material with urethane foam backing. Produced as a complete unit, urethanes can compete with less-expensive materials because it does not require the extensive coating process needed for the olefin-based material, Rose said.
``It depends on where you're going to hit in the marketplace,'' he said.
PUs have not received as much attention as TPOs, though, in part because there are not as many companies investing in its production, said Terry Anderson, director of material and process development for Textron's Trim division.
Textron has contracts in hand for more PU skins, with another 300,000 vehicles slated for the 2003 model year alone.
Typically, slush molding has not worked for a TPO cover skin program, because the rubber and polymer blend does not mix well during the process, Eller said. But the TPO slush molded system debuting on the Infiniti Q 45 - part of Nissan Motor Co. Ltd. - demonstrates that it is possible, he said.
Meanwhile, the spray urethane skin program created by Belgium's Recticel is gaining interest. It was used on 1 million vehicles in 1999, and Recticel recently announced a joint venture with Inoac Corp. of Nagoya, Japan, to consider expanding the spray program into Asia.
There is no one answer to the material that will appear on future generations of vehicle interiors, Rose said.
``The tide's turning and people are going to go their way [for new materials],'' he said. ``Our message is, there is more than one way to get there.''