3M's Bonding Systems Div. (St. Paul, MN) recently introduced an acrylic/epoxy thermoset adhesive film--7303 Z-Axis (7303 ZAF)--that features conductive film particles that allow both mechanical and electrical connection. The adhesive can replace both electrical and mechanical connectors in a range of applications, and is cured by heat bonding under pressure using a hot bar bonder. 3M says the product combines the advantages of pressure-sensitive tack for easy application and alignment with the electrical stability of a heat-cured adhesive.
The film is made with an adhesive matrix randomly loaded with conductive particles. The particles allow interconnection of circuit lines through the adhesive thickness (the Z-Axis) but are spaced far enough apart to be electrically insulating along the plane of the tape. Circuits with spacing as fine as 20-mm (0.02 inch) pitch can be interconnected using 7303 ZAF.
7303 ZAF can be a lighter-weight, thinner, and less-expensive alternative to mechanical connectors--a plus as electronic devices get smaller, less expensive, and more portable. It can be used to make PCB connections with polyester-film flexible circuits that use silver ink for circuitry, such as in membrane switches and touch screens. The film is suited for systems requiring low electrical-interconnect resistance, even after weeks of exposure to difficult environmental conditions like extreme temperature cycles or high-heat and high-humidity storage.
For more information on 7303 Z-axis adhesive film, contact 1-800-362-3550.