Corona treatment of the surface of the plastic film.

Corona treatment of the surface of the plastic film.

Plastic films are often used as the liner of PP woven bags or PP bags, it's easy to create static friction when filling the goods in, then need to do a corona treatment, in corona treatment process, the base voltage is high enough to move the discharge action material (sheet or film) surface. When the film is generally carried out while the pre-treatment film to the film containing an anti-static agent and other additives, it is an advantage of this treatment. Film extrusion, before the storage process found on the film surface bloom additives, which make it difficult to achieve uniform treatment.

A method by which to make the thin film go through the two electrodes, wherein a high voltage is connected to the metal sheet, a high frequency motor. The other is the ground roll, separated by a narrow gap to the high voltage electrode. Metal electrode film to be processed should be more than a little  narrower, to prevent the discharge directly to the roller. Ozone generating discharge, the surface oxide film, it has polarity. The treatment level is determined by the motor output power and the extrusion speed.

Should avoid dealing with inadequate or over-treatment-which will make the surface chalking, brittle, difficult to heat sealing. Poor treatment effect over time, the treated surface treatment and cleaning of sensitive. Corona treatment at atmospheric pressure and high temperature work, and therefore, there will be very severe surface oxidation.

To determine whether the film is treated or not, a simple test method is to flow water through the surface of the film. If the film is not treated, the water will flow away, and after the liquid film will be processed for several minutes. In between these two extremes, there is often a portion of the film processing good, bad adhesion of the two places, so this method is only suitable test for determining whether the treated surface of the film, but can not be measured through the process.

This primitive improved peel adhesion test method was tested using the roll is pressure -sensitive adhesive tape in particular on the film surface, and then measuring the peel strength of the tension. The higher the treatment level, the higher the peel strength.
The surface chemical changes occur can be detected by XPS technique out, XPS can identify the presence of a corona discharge treatment on the polyolefin hydrocarbon, an ether group, an ester group, a hydrogen peroxide group, an aldehyde group, a carbonyl group or a carboxyl group.