Corona discharge system - uses inks or coatings which release no flammable vapours in ozone-free operation

摘要

Applying corona treatment to (un)coated materials, e.g. to bond varnish, colour or an adhesive, the varnish or ink or adhesive are free of solvents which could ignite on release. The corona discharge is near the application roller for the substrate or near the paired lamination rollers. Outside their working position, the corona electrodes are held at a working temp. to give them ozone-free operation, heated, and returned to the working position. Pref. a corona discharge is applied directly after a coating has . been applied to the carrier, to dry it, and the application or laminating roller is used as one of the electrode pairs to generate a corona discharge. The web is subjected to a corona discharge before and after a substrate has been applied using a pressure or counter-pressure roller as one of the electrodes. Part of the heat generated at the corona electrode is transferred to the material by blowing on the electrode. ADVANTAGE - System prevents ozone development at the corona electrodes to improve their efficiency, and gives a small and compact assembly.