Polyurethane long-fiber composites are getting wider acceptance in applications beyond the automotive market at which they were initially aimed.
Polyurethane long-fiber composites are getting wider acceptance in applications beyond the automotive market at which they were initially aimed. For example, a customized PUR composite formulation from Bayer MaterialScience, Pittsburgh, is being used to form skins for a new line of exterior residential doors. Long-fiber PUR is said to give increased dimensional stability and better strength and impact resistance, along with excellent aesthetics. Bayer worked with door and window manufacturer Jeld-Wen of Klamath Falls, Ore., to come up with a blend of Baytec SPR and Baydur STR materials. They were reinforced using Bayer’s Fipur-Tec PUR fiber technology, which chops and mixes glass fibers right in the mixhead before spraying the mix into an open mold. Baytec SPR is a family of two-component, 100%-solids, thick-film spray-coating systems with Shore hardness from 55A to 75D. They are used to improve corrosion, water, and abrasion resistance of metal, wood, plastics, and other materials, in applications such as pipes, tanks, roofing, bridge decks, and truck-bed liners. Baydur STR is a rigid PUR foamed or solid composite system designed for molding with milled fibers, cut rovings, or fiber mats. Applications include auto instrument-panel supports, console and door panels, roof panels, seat trim, spoilers, seat shells, back rests, covers for luggage compartments, engine shrouds, and pick-up boxes. The skins of Jeld-Wen’s doors are dispensed into an open mold using robotic manipulation of a mixhead with a long-glass chopper. The mold is closed to cure the part. Then the skins are laminated to a polystyrene foam core and wood edge frame. Jeld-Wen says the Fipur-Tec system utilizes 35% fiberglass vs. 10% to 12% with the previously used approach of spraying PUR mix onto a glass mat. Added strength is one benefit. Also, this technology allows the company to use lower-cost glass rovings in place of mats, which also reduces handling problems for workers.