Carbon fiber/epoxy prepreg for autocomposites

Aerospace prepereg and fiber supplier Hexcel (Stamford, Conn.) introduced in Paris several prepregs designed specifically for automotive applications.

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Aerospace prepereg and fiber supplier Hexcel (Stamford, Conn.) introduced in Paris several prepregs designed specifically for automotive applications. Topping the list for CT readers was HexPly M77, a rapid-curing epoxy prepreg that allows automotive components and sporting goods to be press-cured in a two-minute cycle at 150°C/302°F (80-bar/1,060-psi pressure). The prepreg’s low tack allows the prepreg to be cut easily by laser cutter. Once in the mold, HexPly M77’s “optimized” gel time allows the resin to flow into contours to produce the geometries required. A Tg of 125°C/257°F enables cured parts to be demolded while hot to speed molding cycles. HexPly M77 is also supplied as HexMC, Hexcel’s high-performance carbon fiber/epoxy compound developed specifically for compression molding processes.

Also new is HexPly M79 low-temperature cure prepreg, formulated for wind blade and marine applications. The prepreg is evolved from HexPly M10, Hexcel’s well-established prepreg resin for marine structures and wind blades. A number of cure cycle options are possible for HexPly M79, including a very low-temperature cure of 8 to 10 hours at 70°C/158°F, or a more rapid cure cycle of 4 to 6 hours at 80°C/176°F. HexPly M79 has an outlife at room temperature of at least six weeks. Hexcel says that when HexPly M79 carbon fiber unidirectional prepreg is used in conjunction with the company’s patented grid technology, a void content in the cured laminate of less than 1 percent is possible, regardless of the part thickness.