Cone extruder makes wood-plastic panels.

Conenor Ltd., Tampere, Finland, has used a new version of its Conex conical-rotor extruder to produce multi-layer flat panels up to 24 in. wide from wood-plastic composite (WPC). In trials, Conenor has extruded a foam core with up to 50% wood and unfoamed skins containing up to 80% wood. Conenor presented this development at the recent Wood-Plastic and Natural Fibers Composites 2006 conference in Baltimore, sponsored by Principia Partners, Jersey City, N.J. The Conex extruder for two-layer WPC sheet uses a nested combination of twin stators with spiral grooves on both sides, separated by rotors with matching whorls of 1-in. holes. The stators' spiral grooves change from deep to shallow, forcing material through the holes in the rotor. The holes cut the material off sharply and pass it to a different channel inside the next stator, producing distributive mixing. Spinning the two rotors in opposite directions produces opposing orientation of the fibers in the two layers, which adds stiffness to the panels, Conenor says.

A 500-mm-diam. system reportedly can process up to 880 lb/hr and can use coarse, moisture-laden wood waste without predrying, as well as paper, cardboard, straw, and various olefinic or styrenic resins. Conex extruders are built and sold to Conenor licensees by Maillefer Extrusion Oy in Vantaa, Finland. Conenor: [phone]/PTDirect: 612FD * Mailiefer: [phone]/ www.mailleferextrusion.com * Principia: [phone]/www.principiaconsulting.com

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