Car seats have been made of polyurethane foam for generations, so when a material comes along to challenge foam in any part of that application, you can expect a hot button to be pushed in Detroit. The substitution material the industry is beginning to look at is polyester fiber. Its fans say it offers more support for passengers and has greater comfort-creating breathability. They add it is easier to recycle than PU foam, and the polyester nonwoven fibers that would be used can be made from post-consumer items like soda pop bottles.
Polyester in seating structures was not being discussed publicly until a seat company showed concepts last month, but it is clear automakers are interested.
The material is on the menu for the U.S. Council for Automotive Research. USCAR, based in Dearborn, Mich., is a 3-year-old organization in which the Big Three vehicle builders collaborate in noncompetitive areas. The goal is to bolster the Big Three's ability to compete worldwide. Consortia under the USCAR umbrella include those working on materials, recycling, composites and environmental research.
Today's car seats spell trouble for recyclers. Seats are made of a variety of materials with degrees of recyclability and they're bulky, cumbersome, heavy and hard to remove.
USCAR is looking at removal techniques that include a device that can rip the roof of a vehicle, reach in and lift out the seats.
Though there is a large worldwide market for used PU foam for such applications as carpet underlay, automakers say they would like a material that could be ground up with the rest of the seat, including the fabric and the backing.
Lear Seating Corp. of Southfield, Mich., is among those keeping an eye on materials.
``There really is no advantage in polyester except recycling,'' said Jim Crankshaw, Lear director of foam and trim development. ``However, recyclability is a real issue. We are very sincere about our efforts in that area. It's more than just lip service.''
Crankshaw said Lear is working with four polyester suppliers he declined to identify.
``The application getting most of our attention right now is the plus pad, the backing material -usually a slab polyurethane foam - under the seat fabric,'' he said.
Lear expects any displacement of PU foam initially will be for backing and will be evolutionary and gradual. Seats with polyester fabric, backing and cushions in vehicles could be in use by 2001, but the firm has no such programs planned, Crankshaw said.
The backing adds a plush feel to a seat's textile, reduces creases in the fabric, permits the smooth shaping of contours, stops rips and can be a fire retardant. The layer of foam can range in thickness from about 2 mills in Europe to as much as a half-inch in the United States.
Lear has found advantages in backing of needled polyester but Crankshaw said no way has been found to remove the thin layer of adhesive between the seat fabric and the backing. That brings on a recycling headache even though the fabric and backing are both polyester.
Another seating expert who asked not to be identified said: ``We've been doing testing in cars on the road but we're a ways from having a product. We're looking at the 1999 or 2000 model year.
``We're looking at a couple of different products right now. DuPont manufactures a small, circular fiber cluster that's used in pillows and linings for jackets, mattresses, comforters. That has its points.''
Polyester cushions have different load-bearing characteristics from foam so they feel firmer, he said.
In 1993, DuPont developed an all-polyester seat cushion for the Ford Escort. Cushion fibers were a two-component system consisting of a support fiber and a co-polyester binder fiber. Those fibers were formed into small spherical clusters that act as tiny springs, Rick Bell, DuPont automotive development specialist, said in a paper delivered at a September meeting of the American Society of Body Engineers in Detroit.
DuPont also developed an all-polyester potential product dubbed the green seat. A green seat would consist of snapped-together polyester parts and could be removed from a vehicle easily for recycling, Bell said.
Johnson Controls Inc. of Milwaukee, another seat maker, showed several seats with polyester pads at an auto show in Frankfurt, Germany, last month saying they are ``significantly lighter and offer more breathability than conventional foam pads.''
GM's Delphi Interior & Lighting Systems of Warren, Mich., used the Frankfurt event to show off its one-piece Opti-Ride suspension seat that replaces the usual four-piece suspension while boosting comfort and cutting costs. Seats can be designed with extremely thin profiles which produces more leg room.
Delphi also showed its 3-D knit seat cover technology that converts yarn directly into three-dimensionally shaped, one-piece seat covers with no intermediate cut-and-sew operations. No sewing is done and patterns can be carried across what used to be seam lines.
