Ozone as a means of adhesion promotion has been successfully utilized in conjunction with extrusion coating for at least thirty years.
Although a proven technology, few people are willing to disclose the enormous benefits ozone offers extrusion coaters.
The likely reason being that proponents of ozone feel they enjoy a competitive advantage over their non-using competitors.
It's important to emphasise two points to avoid any misunderstandings:
- Ozone application does not replace traditional surface treatment systems, instead it's a complement.
- Ozone is intended for application to a melt curtain when extrusion coating and not as a replacement for flame or corona treatment when treating films, foils or paper webs.
Ozone is used for improved adhesion between the extrudate and the laminate, especially when melt temperatures are too low or line speeds too high.
Ozone will help maintain adhesion even as coat weight and melt temperature is reduced.
Since ozone can alleviate some process problems it is necessary to quantify the advantages to be gained by adding ozone to the extrusion coating line:
- Reduce coating weight
- Reduce melt temperature
- Enhanced adhesion
- Achieve higher line speeds
- Optimize melt stability & neck-in
- Improve heat seal characteristics
- Reduce odour and off-taste
Corona Supplies corona treaters and ozone generators (ozonisers) are used by companies using extrusion coating worldwide.
Our ozone generators include all the necessary filters, dryers, flow rate analysers etc and are designed not only to control the amount of ozone that is applied
to the extrudate, but also how it is applied uniformly via our ozone applicators, critical in the process.
Ozonisors, like surface treaters, require proper sizing. Web speed & width directly impact on the required ozone generator size.
Clearly one size does not fit all applications. Therefore, consideration must be given to line specifications and expectations to ensure the appropriately sized unit is specified.
Our ozone applicators are manufactured from stainless steel, with deckling to adjust ozone application and include divert valves.
Safety: An often asked question concerns the issue of residual ozone that may linger around the coating area, and how that may be a health concern for operators.
Although a very valid concern, there really isn't cause for alarm, providing the applicator is installed correctly and the applicator can be properly deckled down
to the minimum treat or application width. Under normal operating conditions, the ozone applied in the nip area is consumed by heat of the extrudate.
Remaining ozone, if any exists, is exhausted through the extrudate fume hood.
Contact Corona Supplies
for further technical information or a quotation.