Now extrude profiles of wood fiber & melamine.Extrusion of thermoset A polymer-based liquid or powder that becomes solid when heated, placed under pressure, treated with a chemical or via radiation. The curing process creates a chemical bond that, unlike a thermoplastic, prevents the material from being remelted. See thermoplastic. wood-plastic composite (WPC WPC (in Britain) woman police constable WPC (Brit) n abbr (= woman police constable) → Polizistin f WPC n abbr (BRIT ) profiles with developmental melamine resins that have a thermoplastic A polymer material that turns to liquid when heated and becomes solid when cooled. There are more than 40 types of thermoplastics, including acrylic, polypropylene, polycarbonate and polyethylene. processing window was presented at the WPC 2007 conference in Seattle last month by Agrolinz Melamine melamine (mĕl`əmēn'), common name for 2,4,6-triamino-1,3,5-triazine. Melamine is a trimer (see polymer) of cyanamide, H2NC≡N, and is synthesized from calcium carbide. International GmbH and WoodKplus, a quasi-governmental research group, both in Linz, Austria. The material, called Hiperesin, is an etherified melamine with increased molecular weight and controlled reactivity, giving it thermoplastic processing behavior. The special resin (WO 2006-136458) has shear-dependent viscosity and can be mixed with up to 70% wood fibers and 5% other additives. The wood/melamine composite, called Hiperwood, is processed in a conventional conical twin-screw extruder at 266 F and extruded into a thermoset profile, which is cured by passing through the heated die. The die-temperature profile starts out cool at the entrance and rises to more than 338 F at the exit--the reverse of conventional thermoplastic extrusion, but similar to a pultrusion Pultrusion is a continuous process of manufacturing of composite materials with constant cross-section whereby reinforcing fibers are pulled through a resin, possibly followed by a separate preforming system, and into a heated die, where the resin undergoes polymerization. die. The benefit of using melamine for WPC profiles is extra-high thermal/mechanical properties. Agrolinz: +43 (732) 6914-0 * www.agrolinz.corn [ILLUSTRATION OMITTED] |
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