What are ESD (ElectroStatic Dissipative) Coatings?
"ESD coatings are partially conductive, which means also partially resistive to current·flow, and can safely usher static electricity to an attached ground and prevent sparking." Dr. Sasha Tavenner Kruger, Research Chemist at Forrest Technical Coatings, explains to Powder Coated Tough Magazine in the July-August 2019 Issue. Below are highlights from the full article published on the Powder Coating Tough website.
"By being only partially conductive, built up charges don't tend to jump to the coated surface all at once, as can happen with fully conductive materials like metals. In other words, the rate of charge transfer is modified (slowed) by the ESD coating. However, ESD coatings are conductive enough that static electricity can't build up on them - the charges are dissipated."
The goal of ESD-coated surfaces is to prevent sparks and shorts, sudden discharge that can damage electronics or lead to an explosion, and the buildup of static electricity on parts that makes them dangerous or hard to work with.
Dr. Tavenner Kruger suggests ElectroStatic Dissipative Coatings for use in situations that benefit from a dissipated charge including:
-Electronics Workbenches: Integrated circuits are notoriously prone to shock damage. This is why they arrive packaged in antistatic bags. An ESD coated workbench can prevent a lot of unintended damage.
-Equipment housings, particularly for electronics or high voltage parts: Semiconductor test equipment, for example, is all housed in ESD-coated cabinets to prevent stray charges from damaging the delicate semiconductor parts being tested.
-Garment or other factories that use racks of plastic bags: In the absence of charge dissipation, the bags can become so charged that they cannot be separated from one another. ESD coatings on work surfaces (which are grounded so that chargecan flow away) can reduce the static cling of the plastic, leading to easier part separation and less of a shock hazard for the workers who must handle the parts.
-Electromagnetic interference (EMI) shielding of circuits: Some circuits produce signals in radio or shorter wavelengths which can interfere with other electronic circuits. Enclosing such circuits in a conductive or ESD (partially conductive) enclosure can, through the Faraday effect, reduce the signal leakage to the point of no longer interfering with other circuits in the area. Conversely, if a sensitive circuit is surrounded by noisy electromagnetic signal sources it can be protected from them by an ESD-coated enclosure. Device manufacturers design and coat such enclosures and can use ESD coatings to accomplish EMI shielding.
-Anywhere with dry winter weather: Due to reduced carrying capacity for water in cold winter air, static shocks can increase, even in processes that don't show this behavior during other parts of the year. ESD-coated furniture, equipment cases, handles, and other parts can make the seasonal change less painful.
ESD coatings can be found in many forms. These include powder coatings, waterborne, solvent borne, and UV-cure. Ranges of resistance typically fall within 106 to 1011 ohms, and an individual coating will usually have a slightly tighter specification than the whole range. The components which make the coating appropriate for ESD use are conductive and are loaded only to the degree needed to make the overall coating “conductive enough” for the specified range.
Visit FORREST's ESD Coatings product page to learn more about our powder coatings with electrostatic properties.