A new type of high-loft, lightweight glass-mat/thermoplastic (GMT) formable sheet is made with basalt fibers in place of glass. Basalt is a type of volcanic rock. VolcaLite sheet contains around 50% random chopped basalt fiber under 1 in. long in polypropylene. It is made by Azdel Inc., Southfield, Mich., and marketed by GE Plastics, Pittsfield, Mass. Like glass/PP Azdel SuperLite sheet, VolcaLite is heated in an oven, causing the glass to loft and produce a porous, spongy slab. This is formed in a compression mold, so the final density depends on the wall thickness. VolcaLite was introduced in Europe early last year and was just introduced here with the commercial launch of the 2007 Honda Acura MDX SUV, which has a VolcaLite headliner (see p. 27). According to Azdel sources, VolcaLite's processing and mechanical properties are essentially identical to glass-reinforced SuperLite. Basalt fibers are 5% more dense than glass and have slightly greater stiffness and strength. They melt at a much higher temperature (1400 C), which means that scrap parts can be incinerated, as is typical in Japan, without leaving behind a residue of melted glass. Basalt is currently more expensive than glass, adding about 20% to the cost of VolcaLite. Azdel is thinking of using basalt in full-density GMT sheet for structural parts like bumper beams.
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