Plastics companies are developing some very unique injection-molding resins that conduct electricity. These manufacturers often utilize nanotechnology to produce tiny metal fibers and strands that are incorporated into the matrix of the polymer. Both the metal’s conductive and physical properties impact the performance of the composite material, so the function of the product or part must be perfectly understood at the beginning of the project.
A wide variety of resins can be “doped” with conductive metal—the most popular resins are polycarbonate (PC), polypropylene, ABS, polyamide 6/6, and PC/ABS. Conductive fillers are typically stainless steel fiber and nickel-plated carbon fiber. Nickel is conductive, magnetic, and corrosion resistant. All these composite materials can be injection-molded (including complex shapes), producing parts that are as hard and durable and conductive as the metallic parts they replace—as well as lighter in weight.
Resins are doped with a specific concentration of micro-sized or nano-sized metallic materials and then pelletized. These particles are then homogenized throughout the material during injection molding. The shape of the metallic particles are also important—they can range from nickel-coated fibers that act as major conductors and ground planes to three-dimensional branched or looped nanostrands that also provide specific mechanical properties and electromagnetic shielding.
Applications for conductive composites abound, including electronics, lighting circuitry, medical devices, cable connectors, antennas, shielding, switch actuators, and thermal equipment.
ElectriPlast Corporation in Bellingham, Washington makes electrically conductive hybrid plastics for industrial, commercial and consumer products and services. Its core product line, ElectriPlast™, is a family of non-corrosive, electrically-conductive resin-based materials whose properties allow it to be molded into multiple shapes and sizes associated with plastics and rubbers—but which is as electrically conductive as if it were metal. By replacing traditional metal parts component weight may be reduced by 40 to 70 percent.
In February the company announced an agreement with Korean firm Hanwha L&C, a global supplier of interior and exterior automotive components made from lightweight materials such as glass fiber mat-reinforced thermoplastic, lightweight reinforced thermoplastic (LWRT), and expandable polypropylene (EPP).
Hanwha L&C conducted extensive independent testing of conductivity, shielding (both electric and electro-magnetic), and mechanical strength; the results met or exceeded all the company’s requirements.
“We see the conductive plastics market as a tremendous growth opportunity and the ElectriPlast technology as a leader in this young industry” says Won S. Choe, Hanwha L&C’s vice president of business development. “We have many potential uses for ElectriPlast in our different lines of business, including our automotive division.”