Taking The Shock Out Of Textiles
Conductive fiber technologies are tools of development in markets where unacceptable static discharge raises concerns.
Jim Borneman, Editor In Chief
. A s many textile manufacturers search for non-commodity opportunities that add value for their customers, products developed for electrostatic discharge (ESD) control have shown promise. Whether for traditional clean-room apparel fabrics or antistatic conveyor belts, products that dissipate electrical charges continue to find their way into a broad array of markets.
The unintended consequences of static discharge can cause serious problems in a number of environments. Explosions in grain storage facilities often are cited as one of the most graphic examples. However, static discharge also can damage products in electronic assembly; prevent production machinery from operating properly; and create a number of quality, health and safety concerns in the work environment. Refineries, medical operating rooms, pharmaceutical manufacturers, paint spraying and powder coating operations, electronics manufacturers, clean rooms and military operations are just some of the places where static-control textiles have served market demand.
In the automotive industry, product applications include seatbelts and upholstery. Bulk bags, antistatic brushes and conveyors and paper-forming belts make manufacturing safer and more efficient. Antistatic brushes inside printers are widely used hidden components. The commercial environment has benefited from using antistatic engineered commercial upholstery and flooring products and the list goes on.
Shakespeare Conductive Fibers manufactures Resistat® fibers using a suffusion process that imparts static control characteristics.
There are a number of solutions to creating fabric formations that control static discharge. Aside from antistatic finishes, various inherent fiber and yarn configurations offering conductive characteristics may also provide benefits in knits, wovens and nonwovens. By incorporating conductive materials into the constructions, the fabrics safely collect and dissipate the static charge. Traditionally, man-made fibers have been combined with conductive materials to provide the necessary dissipation. These fibers then are incorporated into the fabric construction - in some cases woven in a simple check or stripe to produce ample conductivity. In other cases, as little as 1-percent inclusion of conductive fiber can provide enough dissipation to meet the market specification.
Conductive materials typically include either silver or carbon. They are doped, coated or extruded in varying cross sections to achieve the level of conductivity in a polymer that meets end-use requirements.
Other methods apply conductive materials to the surface of the fiber. Additionally, manufacturing techniques have been developed that embed carbon onto the surface of the fiber.
Columbia, S.C.-based Shakespeare Conductive Fibers LLC uses a patented process called suffusion to incorporate carbon particles into nylon for its Resistat® line of products. According to the company, the process chemically saturates the outer skin of the fiber with carbon particles and makes them an integral part of the structure of the fiber. This characteristic makes them both highly conductive and durable. The durability makes them useful in mechanical, chemical and thermal applications. According to Shakespeare, the nature of the suffusion process prevents cracking and flaking that can lead to a loss of conductivity.
Shakespeare's suffusion process chemically saturates the outer skin of the Resistat® fiber with carbon particles.
Fiber To Finished Product
By way of example, one current application of antistatic technology in textiles is the use of Resistat® by Spartanburg-based Milliken and Company. The fiber was used in developing POLYSTAT® fabric, part of the company's Perimeter® product line. According to Milliken, the fabric has found success in demanding applications such as medical device and electronic product manufacturing; and in the paint spray and powder coating markets, where both durability and comfort are needed. "Resistat conductive yarns have allowed us to make woven fabrics that perform as well as knits, but that tailor into a neater, more professional-looking garment, with better coverage and improved durability," said Eric Mossbrook, senior account manager, Perimeter.
Milliken and Company uses Resistat® fibers from Shakespeare in the manufacture of POLYSTAT® fabric, part of its Perimeter® product line.
Antistatic applications continue to grow even though the battle to control ESD is not new.
Applications including nonwoven constructions used for dry filtration and conductive papers and
even the consumer demands for technical-oriented apparel could present opportunities. Knit, woven
and nonwoven fabric constructions offer opportunities to combine varying fabric performance and
cost levels with the added value of antistatic performance.