There are two types of cover tapes that are typically used with embossed carrier tapes on the market today – heat-activated adhesive (HAA) and pressure-sensitive adhesive (PSA) cover tapes.
Pressure-Sensitive Adhesive (PSA)
PSA cover tapes consist of a synthetic adhesive formulated to remain tacky over a wide range of temperatures. Heat is not needed to seal PSA systems. PSA solutions typically eradicate the need for mechanical fastening systems (nails, retaining clips, or staples). PSA systems can drastically improve productivity during the final stages of the assembly process.
Heat-Activated Adhesive (HAA)
HAA cover tapes feature a heat-activated adhesive layer that secures a durable bond to the extruded profile and adheres to a wide range of materials.
HAA cover tapes are commonly comprised of three elements:
An acrylic foam core
A high-performance acrylic adhesive
An OEM-applied adhesive layer that forms the sealing surface
A polyolefin release liner
Naturally, HAA requires a specific activation temperature during the process window in order to seal properly. The process window is a combination of the sealing temperature, dwell time and pressure.
Griffith Rubber specializes in the most popular HAA solutions: polyethylene vinyl acetates (EVA) and styrene-butadiene rubber (SBR). EVA adhesives have a lower activation temperature than SBR adhesives, which have a greater shear stress resistance when compared to EVA adhesives. Simply put, if bonded at the same peel force, SBR adhesives require a higher sealing temperature, but are able to tolerate more shear stress than EVA adhesives.