Foil tapes are constructed with a thin metal-foil backing that provides a malleable and conductive product for vapor sealing, shielding, and ducting-leak repairs. Typically, metal foil tapes are made of aluminum or copper. Aluminum foil tapes are laminated to paper or plastic films for improved strength. Like other foil tapes, they provide a light and relatively inexpensive form of protection for food, medicine, and other products that can be damaged by the environment. Electrodeposited copper foil is used to produce multilayer printed circuit boards (PCBs). Several copper foil thicknesses are available. As a rule, the PCB application determines the proper thickness to select. Thicker copper foil carries more current and has less impedance than thinner foil.   

In addition to backing or carrier material, foil tapes are specified according to adhesive or coating type and release or liner material. Some foil tapes use acrylic, cellulose, epoxy, water-activated, or polyurethane adhesives. Others use rubber, silicone, thermoset or thermoplastic adhesives. Pressure-sensitive adhesives (PSA) or contact adhesives are aggressively and permanently tacky at room temperature in dry (solvent free) form. Heat-activated adhesives become tacky or sticky when heat is applied. Choices for liner material include paper, film, board, fluropolymer, glassine, and silicone. Foil tapes that use clay, wax, of differentially coated liners are also available. 

Foil tapes carry dimensional specifications such as length, width and thickness. They also differ with regard to physical properties such as peel strength, tensile strength, elongation, temperature resistance, and dielectric strength. Peel strength or adhesion is the force required to separate two bonded surfaces. Tensile strength is the force required to break a piece of tape by pulling on opposite ends of the piece. Elongation is the distance that foil tapes can stretch lengthwise. Temperature resistance is the maximum temperature that products can withstand. Dielectric strength is the voltage that foil tapes can withstand without allowing the passage of current. 

Foil tapes differ in terms of substrate compatibility and application. Substrates include ceramics and glass, concrete and masonry, composite materials, foam, porous surfaces, leather, metal, paper and paperboard. Foil tapes that are compatible with plastic, rubber, textiles, or wood and wood products are also available. Products that are designed for dissimilar substrates can bond metal to rubber. In terms of applications, some foil tapes are designed for aerospace, automotive, biotech, electrical, electronic, HVAC, medical and pharmaceutical applications. Others are used in membrane switches and control panels, transdermal patches and drug delivery systems, or semiconductors.