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Need non-conductive coating - to hold a static charge

April 2, 2009

I am in the printing / finishing industry. When handling large volumes of leaflets, booklets or magazines it is sometimes beneficial to add static electricity to the products as they are conveyed to a stacking unit so the stack sticks together in a nice solid block for further handling. To accomplish this the product is passed between 20-30 kv positive and negative charge plates to charge top & bottom surfaces of the paper product with an opposing charge so they will attract to each other. Unfortunately, as the product continues through the process machinery (conveyors, stackers, etc.) it passes over metal rollers and touches metal guides. Ideally I would have fabricated everything in some type of plastic (nylon?), but the static charge device is a retrofit for large amounts of existing metal (mostly steel/aluminum) machinery.

I need to coat steel rollers and any other parts that the product may come in contact with that might drain the static charge back to ground. I don't know what specific material I need to coat them with as coatings are not generally rated for ability to hold a static charge (although I have seen CONDUCTIVE coatings designed to DRAIN static charges). Some insulating materials would work for "normal" electricity, (e.g. spray varnish used to insulate motor windings) but static electricity has strange properties and doesn't always behave like "normal" electricity so I'm not sure if it would work effectively. Also I do not know a way to measure what level of charge is actually retained in the product after passing through the high voltage field so I have no way to measure incremental improvements.

Of course it would be ideal if there was a coating in a spray can that I could just coat necessary items in place on the machine, but we are willing to entertain any ideas, disassembling or even sending parts out if necessary. Any advise or leads would be much appreciated, thanks!

Rob Coon
product designer - Portland, Oregon, USA

I have used Teflon sleeves on equipment to reduce lateral friction with material, unfortunately for my application Teflon had a tendency to build up a large electric charge, we were running a SST web and Mylar leader. UHMW sleeves did not cause us quite as much trouble.

Brian D Paulson
- Minneapolis, MN, USA
October 8, 2009