Electrostatic charging is the physical process by which an excess shortage of electrons that cannot be compensated forms on non-electrically conductive surfaces. This potential difference usually does not pose a problem.

However, if this charge is compensated by flashover and therefore strong pulsed discharge currents, damage may occur on sensitive components. In explosive environments, such as petrochemical sites, these discharges may even pose a risk of ignition.

To protect electronic components in industrial environments from flashover, it is therefore required to continuously remove charge carriers (electrons) from the affected surfaces. Electrostatic charging of belt drives is primarily the result of sliding friction on guide and support rails, friction in the tooth mesh and electric fields. As the thermoplastic polyurethane (TPU) makes timing belts excellent insulators, dissipation of charge differentials can pose problems. To give timing belts antistatic properties, i.e. allow them to discharge electricity, a conductive material is mixed with the TPU. This creates a slightly conductive compound such as BRECOTPU-AS1, with a resistance of
< 108 Ω. Significantly lower still resistance values are achieved by the TPU compounds BRECO-TPU-AS2 and TPU-AS7. The latter is a recent development and offers particularly consistent resistance distribution in the longitudinal and transverse timing belt direction, as well as very low resistance values < 104 Ω.

Another option for making timing belts conductive is coating the tooth and/or belt back with a conductive backing. The antistatic PA backing created by BRECO offers a resistance value of 105 Ω and is primarily used in belt drives serving as accumulating conveyors for electronic components. It also reduces the coefficient of friction to approximately 0.3.

CONTI® SYNCHROFLEX polyurethane timing belts are also available with antistatic properties. A special conductive polyurethane compound is available up to a belt length of 700 mm.

Alternatively, an electrically conductive backing can be sprayed on post-manufacture to all BRECO, BRECOFLEX and SYNCHROFLEX BELTS. Learn more here.

Just ask our team Technical team for help with any anitistatic belt queries.