Dielectric materials, as they are known, come in three main
types: Elasommeric, inorganics and plastics. The choice of which is suitable for you depends on the application,
and of course each material has its own strengths and weaknesses.
Elastomics usually include silicone, bonded silicon and
Hypalon, including some proprietary formulations. Hypalon was one of the most
popular coatings but is very susceptible to pin holing and knife cuts. It is
generally used on larger rolls.
Silicone is not only coated on a roll but can come in a
sleeve form, which makes repair of the roll much quicker and easier. This makes
silicone one of the most popular dielectric coatings. Epoxy coatings have
generally been used as an alternative to Hypalon as it is less likely to
pinhole and has reasonable cut resistance. Ceramic coatings have become very
popular due to their excellent electrical and mechanical properties and lasts
longer than most other materials.
Finally there is glass, which is applied in
several layers using a casting method but has to be applied to specially
formulated carbon steel due to the high temperatures needed to fuse the glass
to the base material. The finished coating is very hard and dense and has a
very smooth finish.