Laminates, panels and methods for making them

Abstract

Sandwich panels and methods of making them, i.e., laminates which comprise two metal sheets with a filled resin core between a bonded metal sheets, which are useful for structural and other uses wherein the laminates utilize combinations of metal skins, metal surface preparation, resins, fillers, and reinforcement bonded together in the sandwich structure to provide a laminate having a flexural modulus of at least 1.7 million psi, a rigidity index of at least about 2,000 and other unique properties which enable the laminates to be particularly useful for thin wall trailer body construction, as well as other structural and non-structural uses. A rigidity index property for sandwich structures and panels and a falling ball impact test are disclosed and used to characterize the properties of sandwich laminates. A laminate of plywood core or a reconstituted wood product core, such as hardboard, particleboard or flakeboard, bonded to prepared metal surfaces with the resin also has properties suitable for structural uses.