The corona treatment was invented by the Danish engineer Verner Eisby in the 1951. Verner had been asked by one of his customers if he could find a solution which would make it possible to print on plastic. Verner found that there were already a couple of ways to accomplish this. One was a gas flame method and the other was a spark generating method, both of which were crude and uncontrollable and did not produce a homogeneous product. Verner came up with the theory that a high frequency corona discharge would provide both a more efficient and controllable method to treat the surface. Exhaustive experiments proved him to be correct. Verners company, Vetaphone, obtained patent rights for the new corona treatment system.
Corona principle and role
Use high-frequency high-voltage on power pole in the discharge between the rollerand corona, low temperture plasma formed by iionization of air between the ploes to produce ozone,which is a strong oxidizer, can change the molecular structure of plastic surface to make it non-polar into polarity. at the same time after the corona treating, it will cause uneven surface hole roughen,it will enhance surface activity, such as the increase in surface tension, that is , ink,glue,etc,willbe able to further penetrate the materials and processed to achieve the idea effect on the printing and glue application.
equipment
Corona discharge equipment consists of a high-frequency power generator, a high-voltage transformer, a stationary electrode, and a treater ground roll. Standard utility electrical power is converted into higher frequency power which is then supplied to the treater station. The treater station applies this power through ceramic or metal electrodes over an air gap onto the material's surface.