Difference between Corona & Plasma
The distinction between corona and plasma depends heavily on the specific context, as different industries have their own interpretations of these terms. In scientific terms, plasma is the fourth state of matter resulting from gas ionization. Considering that corona ionizes atmospheric air (which is a gas), it can be understood as a type of plasma.
Corona and its typical application in converting industry
Corona treatment is a conventional technique used in the film, roll-to-roll, converting, and extrusion industries. The term corona treater refers to systems that ionize air without using any additional gas.
The appearance of the purple corona discharge can vary depending on the dielectrics being employed, ranging from smooth and consistent to filamentary discharges resembling spikes.
This method is well-established in these industries and is highly effective for enhancing surface energy and adhesion in printing, coating, and laminating films.
Industries favor corona treatments due to their rapid processing speed, cost-effectiveness, and lower initial investment compared to plasma treatments.
Corona
Flame Plasma
Air Plasma
Drawbacks of Corona
However, there are important factors to consider when using corona treatments. It is crucial to note that the effects of corona treatment diminish over time, making it advisable to apply adhesive promptly after treatment.
Additionally, not all surfaces respond well to corona treatment. This has led to the development of plasma technologies utilizing gases other than atmospheric air, providing users with enhanced functionality and flexibility. While plasma is technically a form of corona and vice versa, the distinction lies in their physical properties.
The invention of Plasma
The term plasma was originally used to describe surface treaters that were supplied with additional gases like argon, nitrogen, or helium for ionization. Plasma systems are employed when corona treatment, which only ionizes air, fails to achieve the desired treatment outcomes.
In some cases, plasma treatment can produce more effective and longer-lasting surface effects than corona treatment, but the advantages must justify the additional equipment investment and operational costs.
Early corona systems used for treating objects typically had low power and were effective only in specific applications. As the technology of these corona systems evolved, they became significantly more efficient at treating objects. Significant enhancements in power supplies and treatment discharge heads resulted in improved performance.
However, manufacturers had to overcome the market’s prior experience with the poor performance of early corona treaters when treating objects. The term Air Plasma was introduced to categorize these systems.
In numerous aspects, the distinctions between corona and plasma boil down to language. Both methods have similar basic processes and applications. Both corona and plasma can offer economic adhesion and effectiveness, but the particular use case will ultimately determine which is more suitable.
Comparison Table of Plasma & Corona
Properties | Corona | New Corona Technology = Air Plasma | Special Gas Plasma |
State of matter |
4th State of Master | ||
Input/ ionize material | Air | Air | Argon, nitrogen, helium |
Power | Low | High | High |
Surface treating effectiveness | Low | High | High |
Special surface treating effectiveness | Low | Meidum | High |
Time of effectiveness | Short | Long | Long |
Investment | Low | Quite high | Quite high |
Ownership cost | Not optimized | Optimized | Optimized |
Industries | Paper/ converting industries | Plastic/ Metal/ Advanced Industries | Plastic/ Metal/ Advanced Industries |
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