Corona treater

Figure 7.10 Schematic diagram of a corona treater under an organic vapor.i (f) Metal roll, (2) stationary hollow tube, (3) distributor duct, (4) enclosed chamber.

Corona discharge treatment (CDT) was carried out on a GXIO corona treater, manufactured by Sherman Treaters, Thame, UK. The films were exposed to one pass under an electrode of width 0.4 m, in ambient air at a speed of 10 m/min. The various power settings used were converted to... 

Automated processing equipment is possible, similar to the corona treaters. Hand-held equipment such as a torch or Bunsen burner can also be used, although uniform treatment is more dififlcult. The effect of additives on treatment efficiency is not as great as with corona treatment. 

An industrial corona treater normally operates in a frequency range between 10 and 50 kHz and output powers over 50 kW because the width of unit can be up to 10 m with operating line speeds over 500 m/min [28,68]. 

A range of commercial equipment suppliers offer standard corona treaters (based on filamentary DBD) include, Enercon (USA) [35], Ahlbrandt (Germany) [80], Softal (Germany) [81], AFS (Germany) [82], and Vetaphone (Denmark) [83], Some typical industrial corona treaters are shown in Fig, 20,15,... 

Tantec, headquartered in Denmark [84], has developed several corona treaters for surface activation of various plastic parts. One example is the RotoTEC-X system, which is used for in-line corona treatment of injection molded parts prior to coating, printing, gluing, and painting for optimization of the adhesion properties of a given substrate, mostly polypropylene and PE (Fig, 20,16),... 

Figure 20.15 Examples of some industrial corona treaters, (Part A Reproduced with courtesy of Enercon Industries Corporation Part B and C From Reproduced with permission from Softal Part D From Reproduced with permission from Ahlbrandt GmbH).

Figure 20.17 Corona treater for surface activation of plastic parts. (Reprinted with permission from Tantec AIS).

Figure 5.10 Examples of 3D Corona Treater offered by four equipment manufacturers. ...

A comparison of an atmospheric plasma and a 3D corona treater is given in Table 5.12. 

It is important that metal or metallized surfaces be in contact with a clean and grounded idler roll along its path through the corona treater. This idler roll can be covered with conductive ceramic to prevent oxidation and provide a ground path from the conductive material surface. 

The trial runs were performed on a bare roll corona treatment system as well as on an atmospheric plasma treatment system, resident at the same pilot line. For all runs, two PVdC-coated polyester films were post-treated, one in the APT system with a helium/oxygen plasma, the other by means of a corona treater. Another sample constituted the control reference and was not treated. The samples were then printed at 90 mpm on a PCMC press with aqueous ink (Flint Ink) using a laser-engraved anilox roll to 300 lines per inch (Ipi) and a cell volume of 4.8 billion cubic microns (bcm)/sq.in. The printed image provided solid (100%) ink coverage. The calculated ink transfer (thickness) to the film, based upon this cell volume, was approximately 1.9 microns. The printed web drying temperature occurred at 121 °C, with a web temperature of 77 °C. 

Aqueous solutions of cationic polyacrylamide (0.25 wt. % in deionized water) were prepared by rolling for 48 hours. Suspensions of 0.2 wt. % clay in deionized water were similarly prepared. Each 10 x 10 cm piece of PET film, rinsed with methanol and deionized water, was corona treated with a BD-20C Corona Treater (Electro-Technic Products Inc., Chicago, IL), prior to LbL deposition. The substrate was initially dipped in the C-491 solution for 5 minutes, followed by rinsing with de-ionized water and blow drying with air. This same procedure was followed with the clay solution, followed by one minute of deposition for all subsequent dips. The entire dipping procedure was accomplished with a home-built robotic system (12). 

Figure 80 Types of treater for applying corona discharge (a) for non-conductive substrates, with an earthed base roll covered with a dielectric (b) for material of all types, with a bare, earthed base roll and the dielectric on the discharge electrode The main components are (1) Multi-fin electrode (2) Electrode tube in ceramic or quartz (3) Earthed base roll covered with dielectric (4) Bare, earthed base roll (5) Housing for the electrode assembly, enabling the extraction of ozone and cooling of the electrode (6) Path of material being treated...

Bare roll treater rolls are typically specified to have smaller diameters than those of covered roll systems, because of the area of dielectric required to dissipate the heat generated in the corona. With bare roll systems, the diameter is dictated by the length of the roll (driven by the maximum material width to treat) and the number of electrodes required (specified by the Watt density requirement). This dielectric-less ground roll design is always paired with dielectric-surfaced (typically ceramic) electrodes to promote uniform corona discharging to both conductive and non-conductive material surfaces. 

M. Nolan, S. Greig, N. Jadon, Corona, Ozone and Flame Treaters for Extrusion Coating Lines , p. 4. 

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