NASHVILLE, TENN. — Claiming it's time to ``stop the chop'' when manufacturing sheet molding compound, officials of PPG Industries Inc. say a new glass mat could replace chopped-glass roving.
Currently when making SMC, strands of glass roving are fed from spools through a long-blade chopper. The glass fibers then fall onto a sheet of resin paste passing underneath.
PPG's MatVantage SMC replaces that setup with a glass mat provided by the Pittsburgh company. PPG claims MatVantage creates a more-uniform mat weight and size, reduces edge trim waste and eliminates the difficult process of synchronizing chopper speed with film speed.
``Because we supply a square-edged product, it greatly reduces the amount of edge trim,'' said Thomas Wagner, marketing director for thermoset reinforcements.
PPG unveiled MatVantage Jan. 27 at the International Composites Exposition in Nashville.
``The mat controls the integrity'' of the final SMC product, Wagner said.
PPG plans to ship MatVantage on tolls and also layered, known in the trade as festooned, in corrugated boxes.
Kevin Sullivan, reinforcements general manager, said using a pre-made mat will be much easier than the complex setup of creel areas and tubing to carry the strands to the chopper.
``Removing roving from the operation has the added benefit of eliminating fuzz and fly issues, strand entanglement problems and chopper investment and maintenance,'' he said.
Also during the Nashville show, PPG introduced a chopped-strand reinforcement for polyphenelyne sulfide called ChopVantage.
PPG also announced a new roving, Type 7810, for continuous panel lamination. Because the bundles of glass strands break up completely, the product is good for making filled and pigmented opaque panels that have a very flat, smooth appearance. Applications include truck trailer liners, road signs and sanitary paneling.