ElectRelease Electrically Debonding Adhesive: Technology

Technology

ElectRelease resins (patent pending) are a family of high strength adhesives that posses the remarkable property of being released when a low power current (d.c.) is applied across the bondline between metallic substrates joined using these resins. A battery, attached to metallic substrates, provides sufficient current to debond the substrates in a matter of seconds, allowing the substrates to be easily snapped apart.

For successful debonding of ElectRelease, both surfaces must be electrically conductive. They can be metals, carbon-fiber composites, metal-filled adhesives and coatings, or conductive oxides. Some surfaces may require slight abrasion to expose conductive fillers. Best results are obtained when the entire surface at the debonding interface is conductive.

Debonding occurs along the interface between the anodic or positive metal substrate and the resin. The process is rapid, consumes little power, produces no heat, uses no solvents and generates little or no gaseous or liquid wastes. The surface of the debonded metal substrate is left virtually free of any residual adhesive.

Current products include ElectRelease-E4, a high strength aliphatic amine cured epoxy and ElectRelease-M4, a moderate strength epoxy, which is swellable in methanol. This allows residual cured adhesive to be easily removed from delicate surfaces. The recently developed ElectRelease adhesive patch, permits this technology to be extended to the adhesive bonding of non-conductive substrates, such as plastics, composites and painted metal surfaces. Novel adhesives, including high temperature and rubber-based compositions are under development.

Debonding Process

ElectRelease is formulated to have slight ionic conductivity when cured. When a voltage is applied, electrical current flows across the bondline. The current is very low, < 1 mA/cm², but sufficient to release the adhesive bond at the positive interface.

A d.c. power source is attached to the bonded substrates (a battery will suffice) initiating a reaction at the metal/resin interface.
Depending on the applied potential (10-50 volts recommended), the substrates can be snapped apart in seconds.
Debonding occurs at the anodic (positive) interface and is entirely interfacial, leaving the metal virtually free of adhesive.
The process is self-limiting. Bonded substrates do not need to be either flat or parallel. However, the two substrates must not be electrically shorted to one another or no debonding will occur.
The technology can be applied to non-conductive or coated substrates using an aluminum foil patch pre-bonded with ElectRelease. The commercially available patch can be cut to size and inserted into any bondline using an additional adhesive, such as epoxy, cyanoacrylate, etc. Subsequent treatment with a d.c. potential results in debonding.

ElectRelease was developed with the support of a U.S. Air Force Small Business Innovations Research contract. U.S. and foreign patents pending.