The recipient of the 2007 Frost & Sullivan North American Excellence in Technology Award in automotive body paneling is Azdel Inc. (Forest, Va.) for its development of high-performance thermoplastic composites.
Azdel Inc., a joint venture of GE Plastics (GEP) and PPG Industries Ltd., has developed a high-performance thermoplastic composite (HPPC) family of products that reportedly overcome the limitations of traditional reinforced thermoplastics. These traditional reinforced thermoplastics lacked sufficient stiffness to prevent creep across large, unsupported horizontal surfaces and caused fit-and-finish problems in automotive applications.
The company’s reinforced thermoplastic sandwich structure offers horizontal body panel molders not only lower specific gravity at a given modulus (hence, lower part mass) and greater ductility plus impact toughness than metals or thermoset composites, but also lower tooling costs, a Class A surface, and faster cycle times.
Azdel's Superlite, a low-density glass mat thermoplastic with long glass fiber reinforcement, forms the core of the HPPC sandwiched between two-ply skins of continuous unidirectional glass fiber wetted out with thermoplastic resin. Tough, thin, continuous fiber-reinforced skins offer a balance of mechanical and aesthetic properties plus cost efficiency, while improving part stiffness significantly without adding appreciable mass or thickness.
The company's HPPC portfolio takes advantage of the flexibility provided by the HPPC sandwich construction, allowing HPPC properties to be tailored by altering the core/skin resin system and layer construction. The composite thickness and number of tape layers, reinforcing fiber orientation, fiber material, and/or matrix type can all be varied to suit the application. Additional layers of unidirectional reinforcement raise the stiffness of the composite system, while unpainted solutions are possible using Lexan SLX films. For automotive body panel applications, HPPC must be capable of delivering Class A surfaces out of the mold and to be cost-effective at production levels, with mold cycle times on the order of two minutes required.