초록 ▼

A composite structural panel includes a cover sheet laminated onto a three-layered substrate including a thermoplastic foam core sandwiched between two composite outer layers. Each composite outer layer includes natural fibers embedded in a thermoplastic matrix. The thermoplastic material of all lay

A composite structural panel includes a cover sheet laminated onto a three-layered substrate including a thermoplastic foam core sandwiched between two composite outer layers. Each composite outer layer includes natural fibers embedded in a thermoplastic matrix. The thermoplastic material of all layers is preferably polypropylene, and the core consists of an expanded cellular polypropylene rigid foam. In a method for forming the composite structural panel, a first preheated outer layer is laminated and molded onto the foam core in a first molding step, and then the second preheated outer layer and the cover sheet are laminated and molded onto the foam core in a second molding step, with a cooling-down time allowed between the two molding steps. In this manner, each preheated outer layer provides enough heat to thermally fuse the outer layer onto the foam core, without overheating the foam core to the point of softening or melting the foam core. The low density foam core provides a spacing distance between the strong composite outer layers, and therefore the finished composite structural panel has a high strength and rigidity, and a high strength-to-weight ratio. The structural panel can be molded into any desired three-dimensional contoured configuration during the molding process.

대표청구항 ▼

[ What is claimed is:] [1.]1. A composite structural panel including a substrate that comprises:a core layer comprising a thermoplastic foam;a first outer layer that comprises a first thermoplastic material and first natural fibers, and that is thermally fusion bonded onto said core layer by thermal

[ What is claimed is:] [1.]1. A composite structural panel including a substrate that comprises:a core layer comprising a thermoplastic foam;a first outer layer that comprises a first thermoplastic material and first natural fibers, and that is thermally fusion bonded onto said core layer by thermal fusion of said first thermoplastic material with said thermoplastic foam; anda second outer layer that comprises a second thermoplastic material and second natural fibers, and that is thermally fusion bonded onto said core layer opposite said first outer layer so that said core layer is sandwiched between said first and second outer layers, by thermal fusion of said second thermoplastic material with said thermoplastic foam;and wherein said structural panel excludes glass fiber, polyurethane, epoxy, and adhesives.