NOVI, MICH. — Carbon fiber has been getting all the composite glory lately, but suppliers of some more traditional composite materials point out that improvements to the old standbys are making them more competitive, too.
“If you look at some of the early products and compare it, we’ve almost cut processing time in half,” said Michael Super, business development manager for Bayer MaterialScience LLC’s reaction injection molding and composites group.
Sandwich composites using Bayer’s Baypreg urethane are seeing new opportunities in load floors and package trays, replacing parts previously made with textile-wrapped plywood or plastics with steel support structures.
During the Society of Plastics Engineers’ Automotive Composites Conference and Exhibition, held Sept. 11-13 in Novi, Super noted that urethane composites are used both in specialty vehicles like General Motors Co.’s electric Volt and mainstream volume products like Ford Motor Co.’s Escape sports utility vehicle.
Improvements in both processing and the material itself have made urethane composites more competitive just as the global auto industry looks for ways to reduce weight. A sandwich composite with a honeycomb core made of paper, thermoplastics, foams or other materials make it possible to produce structural parts that are 60 to 70 percent lighter than a reinforced structure using steel or plywood, Super said.
“You’re not talking about 1 or 2 pounds,” he said. “It’s reasonable to expect 20 to 30 pounds out of these vehicles on some parts.”
Improvements in the resin formula also make it possible for molders to see cycle times of less than a minute — at least 30 seconds faster than previous generations of urethane parts. That means automakers can consider using the parts in vehicles with a higher production volume, Super said.
The parts have an inner core that are sprayed with polyurethane, placed in a compression molding press then cured. Initial production of urethane sandwich composites was for small parts, such as sunshades, but have moved on to door panels, spare tire covers, load floors, sun roof cassettes and other components.
The urethane parts are more widely adopted in Europe and Asia, Super said, but North American automakers are now moving toward wider use, which is prompting increased investment in manufacturing infrastructure in North America, so suppliers can produce the same parts globally.