Vulcanised silicone rolls are generally used in applications such as cast film extrusion and wide web extrusion, where large diameter and wider base rolls are used and where fitment of a sleeve becomes difficult. Vulcanised silicone provides an excellent treater roll dielectric that is harder wearing than a sleeve, and this is essential where high web tensions are specified, for a silicone sleeve under these conditions may come away from the roll core.
Corona Supplies covers the corona treater roll with 4mm thick silicone vulcanised rubber to 80 IRHD ±5 hardness. The covered roll is subsequently ground to the required dimensions and certificated for compliance, giving excellent tolerances on roll diameter and concentricity - essential at today's high speeds.
The finished coated surface is free of pinholes and inclusions making it suitable for the corona discharge process. The finished surface is tested to withstand 25KV, and to have a dielectric strength between 400 and 750 volts per mil (0.001), with surface dielectric constant not exceeding 3.
It is recommended that you have at least one spare vulcanised roll. Repairs to the silicone surface are possible, but experience has shown that they are short-lived and replacement is the only long term solution.
Contact Corona Supplies
for a quotation for a new roll or to recover an existing corona treater roll.