Bayer highlights flexibility of rigid polyurethane systems
While the material polyurethane may normally be associated with foam, it has a much more diverse array of uses when coupled with various processing techniques, as evidenced by the presence of Bayer MaterialScience LLC at the recent Composites 2013 exhibition in Orlando, Florida. From filament winding to long-fiber injection molding, polyurethanes can be processed in a variety of ways to meet the many needs of manufacturers serving a broad range of markets according to Bayer.
January 30, 2013
Long-fiber injection technology (LFI) provides manufacturers and designers a wide breadth of options. LFI can produce parts with nearly vertical walls, as well as very large parts not currently possible through other common manufacturing processes. LFI allows designers to decorate parts inside the mold using a polyurethane elastomer skin, two-component polyurethane paints, films, fabric or vinyl skins. To demonstrate LFI, Bayer featured applications created using the LFI process: a complete harvester roof made on the largest LFI press in the world, and spa cabinet sections from Dynasty Spas, all produced by Romeo RIM.
Bayer developed its Baypreg two-component spray polyurethane system to be utilized with different combinations of reinforcing mats and honeycomb cores. The resulting composite possesses high load-bearing properties for horizontal parts. This system is often used in automotive applications. A load floor from Ford and one from the Chevy VOLT were featured at the Bayer booth. Load floor applications benefit from the Baypreg composite's extremely high strength-to-weight ratio.
Bayer has long produced custom performance-enhancing polyurethane resins and systems for use in the reaction injection molding (RIM) process. At its booth, Bayer also features a large and intricate Dodge Viper bumper molded through the one-shot RIM process by Romeo RIM.
Bayer developed a proprietary urethane formulation tailored specifically for the filament winding process commonly used for manufacturing cylindrical structures such as pipes and tanks with composite resins. Filament winding offers a fast cycle time and produces parts that are strong and lightweight according to Bayer.
Processing polyurethanes via the pultrusion process, meanwhile, results in dramatically stronger end products. Additionally, the polyurethane pultrusion process uses no styrene, making it more environmentally friendly. Gulf Synthetics' PURLoc sea wall and several innovative and cost-saving applications from Conforce - a marine shipping container floor, lightweight shelving and a forest-saving and worklife-extending lightweight flooring system for tractor trailers - are examples of the potential for pultruded polyurethane parts.
Superior strength and low thermal conductivity also make polyurethane pultrusion technology ideal for window frames says Bayer. Commercially available products include the Graham Architectural Products' GThurm window and frame, and the Deceuninck INNERGY rigid, lightweight window stiffener.
Bayer pioneered the use of polyurethane resin in the resin transfer molding (RTM) technology process. A key advantage of using polyurethane resin in the RTM process is its improved physical properties, such as strength and stiffness, compared with other resins, such as unsaturated polyester or vinylester. The superior toughness of composite parts manufactured with polyurethane through the RTM process has opened the technology up to completely new markets, including ballistics, sporting goods, hydrogen tanks and composite manhole covers.
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