What Are Static-Dissipative Materials?

Electrostatic discharge (ESd) materials are plastics that reduce static electricity in order to protect electrostatic-sensitive devices or to contain flammable liquids or gases. These materials are divided into three categories: anti-static, conductive, and static-dissipative materials. ESd materials are classified by how quickly electricity moves through the material, with that speed referred to as the “resistance” of the material. Static-dissipative materials are considered to be the ideal range for ESd materials, allowing an electric change to flow to ground slowly and in a controlled manner.

Conductive vs. Static-Dissipative Materials

Conductive materials have a very low electrical resistance, allowing electrons to flow easily across their surface or through the bulk of the material. Electric charges are dispersed quickly, either to ground or to another conductive material in contact with the object. Because of this ability to move energy easily and quickly, conductive materials are typically used to make grounding materials. When people think of conductive materials they generally picture metal, as it is the most famous ESD conductor. Since plastic is naturally insulative (has a high electrical resistance making it difficult to ground), it must have filler added – typically carbon – to provide a path for the charge to bleed off.

Static-dissipative materials, on the other hand, allow electric charges to flow more slowly through the material for greater control. These materials are typically used to prevent discharge to and from human contact. The body is a high conductor of energy and can easily create a static spark. A plastic static-dissipative material causes that spark to flow slower, emitting a lower energy to the ground to prevent discharge and possible damage to any sensitive items. This makes them the ideal ESd material for objects that experience frequent human contact.

We offer a wide range of static-dissipative materials, including:

• Tecaform™ SD – This natural copolymer acetal has static dissipative characteristics, contains no carbon fibers or powders, and is generally accepted for clean room use. It has excellent bearing and wearing characteristics and a surface resistivity of 10 9 to 10 11 ohm/square, making it ideal for moving components that may experience frictional or fluid-flow static charges.
• Semitron® ESd 520HR – This PAI (polyamide-imide) plastic was the first in the industry to combine high strength and heat resistance with static dissipation. It has the ability to resist dielectric breakdown at high voltages, whereas many carbon fiber enhanced products can become irreversibly more conductive when exposed to high voltage. Semitron® ESd 520HR also offers high strength and heat resistance, with continuous use up to 500ºF.
• PEEK ESd – This carbon-reinforced plastic offers all the incredible properties of PEEK with the added bonus of static-dissipative properties. PEEK ESd has high structural strength and stiffness, excellent dimensional stability, and heat-deflection temperature of 480ºF. Like Semitron®, PEEK ESd can also be exposed to moderate voltage while maintaining both its dielectric performance and its mechanical properties.

If you have a project that requires static-dissipative materials, high-end machining, and tight tolerances, call Reading Plastic today at (610)-926-3245 or email site2@readingplastic.com. With our decades of experience in precision specialty plastic machining we can help you choose the right plastic for your project and deliver the high-performance parts you need.