Abstract

Laminates are composites made from stacked plies of resin-treated materials that are most often consolidated under heat and pressure to from a unitary structure. Thermally fused layers of various types of thermoplastic film are also considered to be laminates, but the principal topic of this article is reinforced laminates used for decorative and industrial purposes as defined by the National Electrical Manufacturers Association (NEMA) classifications. The reinforcement material is often paper, and the usual resins are thermosets such as melamines, phenolics, polyesters, and epoxies. Solutions of the resins are used to treat the paper, the solvents are evaporated off, and then the dried plies are collated like a deck of cards to make a structure having useful final properties. The stacked plies are inserted together with caul plates into a flat bed press where heat and pressure are applied to cause the resins to flow to form interlaminar bonds between the plies and eventually to cure into a final thermoset state.

After pressing, the laminate edges are trimmed and their backs may be sanded to improve bonding to substrates in later fabrication operations. Laminates may be used for decorative purposes such as countertops or furniture or in industrial applications such as insulator boards or printed circuitry. Laminates may have special fire-retardant properties or be antistatic for use in computer desks. Being thermoset plastics, laminates are quite inert materials and are safe in many instances for food preparation usage. Direct recycle of scrap is difficult, but regrind is used for fuel, and its use as a filler for molded articles has been suggested. Vol. 14, pp. 1074–1091. 18 refs. to July 1993.