High temperature resistance and antistatic are essential characteristics of pressure sensitive tape

High temperature resistance and antistatic are essential characteristics of pressure sensitive tape

This paper relates to a pressure-sensitive adhesive tape structure that can be used to mask printed circuit boards (PCBs) at high temperatures associated with wave welding operations. This type of adhesive tape consisting of ionic conductive polymeric particulate adhesive has high friction electrostatic resistance and thus can protect electronic components from static electricity formation. In addition, when the adhesive mask tape is removed from the PCB, no adhesive residue will stain the surface of the board.

Process description

Wave welding is commonly used to permanently attach electronic components to printed circuit boards. During wave welding connections, the various methods used to mask or cover the plate do not want flux in the area. Such masks are known to be obtained using self-adhesive tapes based on high temperature resistant polyimide films coated with silicone-based adhesives. However, the removal of such adhesive strips from the surface of the electronic assembly results in a frictional charge caused by static electricity, which damages sensitive electronic components and leads to contamination of the printed circuit by silicone.

Conductive tape can also be used for masks. Conductive tape does not cause friction charges as easily as tape made of insulating material such as silicone, so the use of conductive tape reduces the failure rate of electronic components during assembly operations.

A variety of different types of conductive strips are known to be available at room temperature using US patents 31049853832,598 and 4749612 describe adhesive strips with a carbon black binder coating that is said to eliminate static charges. Many patents also reveal multilayered ribbon structures in which one, usually buried, the layer is conductive.

For example, Japanese publication J63012681-A reveals a strap with an intermediate antistatic polymer layer between the polyolefin substrate and the rubber bonding layer.

European patent EP0422919-A2 discloses a band having a conductive particle or foil layer surrounded by a binder between a polymer film substrate and a silicone binder layer. It is said that the use of a high-temperature film substrate, polyimide, combined with a silicon binder and an adhesive can produce a tape that performs well as a wave welding mask at high temperatures where previous antistatic strips are not applicable. That is, the tape can remain intact in the wave welding groove at a temperature of 250℃ for 5 seconds.