The very low dielectric constant
and dissipation factor combined with the high dielectric strength
and high-temperature capability of PTFE, FEP, PFA and the matrix
resins create formulations that are excellent insulators. As
such, they can be used to insulate components from low levels
of electrical energy.
This insulating property renders
a coated surface a good capacitor. When there is particle or
air motion, or other static-charge-inducing systems, conventional
Xylan coatings should be used with caution in the presence of
static-sensitive products such as integrated circuits.
A fluoropolymer coating is used
on GM 6076-M as a masking coat for threads, protecting them
from the heavy buildup of today's electrodeposited primers (a
problem not only in automotive applications, but also in furniture,
building equipment, etc.). The PTFE-based coating "masks"
the threads and provides easy removal of the primer by the mating
nut or bolt. In addition, the coating makes no difference in
torque between the coated parts and similar but non-primed fasteners
in adjacent areas.
Conductive coatings
When formulated with carbon black, graphite or metallic compounds,
coatings can be used as conductors. These formulations are preferred
for static-sensitive systems such as computer printers and plotters,
plastic web-handling equipment or parts that operate in explosive
atmospheres. Resistivity can range from 0.1 to 10,000 ohms,
depending on the additives selected to make the coating conductive.
An example: Webs in paper and
textile mills can be too dry to be conductive, so a static charge
may build up in the dryer roll and become a safety hazard. A
conductive coating of Xylan solves the problem by providing
the release without the static buildup.
When coatings are used to insulate
or conduct, they should be applied in films of at least 25 microns/0.001
in. for maximum effectiveness. Coatings of less than 25 microns
tend to be discontinuous, and do not provide insulation or conductivity.
Note: Be sure that conductive surfaces are fastened securely
to ground.
