Electrostatic discharge materials

Conductive ESD bag with a network card inside
ESD shoes with carbonized rubber (weakly conductive) bottom

Electrostatic discharge materials (ESD materials) are plastics that reduce static electricity to protect against damage to electrostatic-sensitive devices (ESD) or to prevent the accidental ignition of flammable liquids or gases.

Materials

The properties relevant to a material in an ESD context are:

MaterialOhms per squareShieldingAntistaticDissipationIsolationPurpose
Metals< 10−3YesYesToo fastNoUsed as shielding layer in some moisture-barrier laminates (ESD bag).
Metalized film10−1 to 102YesYesToo fastYesUsed as part of shielding laminates and some moisture-barrier laminates (ESD bag). Always appears silvery-translucent.
Carbons (graphite powders and fiber)1 to 103YesYesToo fastNoNot used in pure form as it generates powder easily. May be incorporated into composite materials.
Conductive plastic (carbon-loaded)103 to 10530%YesYesLowUsed as a film to make ESD bags. Also used to make solid plastic pieces (e.g. boxes), foam, and bubble-wrap. Always appears opaque black. Carbon-loaded elastomers such as rubber and Ethylene-vinyl acetate are also used.
Dissipative plastic107 to 1011< 10%YesYesYesUsed as a film to make ESD bags. Also used as a part of shielding laminates. Also used to make foam and bubble-wrap. Typically translucent pink due to added coloring.
Insulators and base polymers> 1013NoNoNoYesNot an ESD material: charges will build up.

See also

References

  1. 1 2 Choosing The Right Bag (PDF). Bradenton, Florida: Ground Zero Electrostatics. p. 2.
  2. ↑ JESD 625-A Requirements for Handling Electrostatic-Discharge-Sensitive (ESDS) Devices https://www.defsup.com/images/JESD625a.pdf. Revision of "EIA-625".

Further reading