Flame vs plasma vs corona treatment
Do you know that corona, flame, and plasma are the three most renowned techniques for treating surfaces? However, you will also find different, less recognized variations of these techniques. The type of pretreatment you will use mostly relies on the application. Let’s find out more about these treatments.
Corona treatment
The first treatment in this list is corona treatment. In this treatment, non-polar substrate’s surface molecules get freedom from their bonds due to the use of the energy from a highly charged electrical corona. Recombining the broken bonds with free radicals creates new polar groups with more energy and better wettability on the surface.
Almost every material can be used for this process, improving the bonding capacities of occasionally challenging materials.
Pros
- Strong usability and lower cost.
Cons
- Static electricity can result in electronic obstruction, shocks to employees, fires, and explosions.
What can the treatment be used for?
It can be used for various treatments, including wide plastic webs, foils (PE, PP, and PVC), sheets, metallized film, aluminium foil, or paper with a thickness of up to 10-15 mm.
Which industry is it mostly used for?
It is mostly used in the extrusion of films and sheets, flexible packaging conversion, packaging, etc.
Plasma treatment
The second treatment is known as plasma treatment. There are several ways in which plasma treatment is comparable to corona treatment. However, a plasma treatment feeds gases into the corona plasma to change the material’s reactivity. By adding a particular functional group to react to particular materials being bonded, this additional plasma application helps further improve the surface treatment and adhesion because some materials do not respond well to the corona treatment.
There are several plasma surface treatment technologies, such as atmospheric plasma and vacuum plasma.
Pros
- Treatment of 3D objects
- Increasing surface energy is simple and only requires one step.
- The cost of each treatment is also very inexpensive per unit.
- The capacity to provide very valuable features to products
Cons
- Plasma treatments are very expensive.
What can the treatment be used for?
Wide plastic webs, aluminium foil, paper, or sheets up to 10-15 mm thick (PE, PP, PVC), metallized film, etc.
Which industry is it mostly used for?
Electronic (conductors, semi-conductors, and insulators), automotive, medical, packaging, home appliances, electrical cables, hydraulic pipes, etc.
Read more about surface treatments for different industries.
Flame treatment
Third treatment in this list is flame treatment. Parts can assist disrupt surface-level molecular interactions and stimulate surface free radicals by passing through the oxygen-rich region of the flame. This increases the surface energy and increases the surface’s receptivity to adhesives and printing inks. Compared to corona therapy, flame treatment is quicker but lacks corona’s adaptability.
Pros
- Two major benefits are the capacity to evaporate certain contaminants on the plastic surface and a very quick treatment rate.
- In contrast to corona discharge, flame treating doesn’t create ozone and, as a result, doesn’t call for ozone removal equipment.
- It is very economical.
Cons
- It can cause scrap in a processing line and the material to be destroyed, resulting in a loss of earnings.
- Repeated treatment will create carbon on the surface, inhibiting bonding.
What can the treatment be used for?
Because the pieces are thick, large, and shaped in a certain way, flame treatment is often used to process injection and blow-moulded items.
Which industry is it mostly used for?
Important industries include film and flexible packaging, consumer products, automotive, textile, medical devices, and even aerospace.
Frequently Asked Questions
Here are a few frequently asked questions.
Flame treatment equipment
It needs a special conveyor and a gas source for the burners. The consistency and range of the treatment depend on the burner and conveyor being chosen properly. You should remember these points while purchasing equipment, including product shape, design, and polymer substrate.
What is the effect of flame on plastics?
Flame plasma treatment is used to increase the wettability and adhesion of plastics.
Why do flames treat plastic?
Before applying coatings and adhesives, polymers that have been flame treated have better adhesion properties. Bond strength and durability are significantly increased with flame-treated surfaces.
Flame treatment technology and its applications
- Automotive – For painting and adhering instrument panels, bumpers, and other surfaces.
- Laminating, coating and printing benefit from improved adhesion due to web conditioning or treatment.
- Plastics – Flame treatment provides improved marking and adhesive options for cups, caps, cables, and containers.
- Film – Printing for confectionery, snack foods, gift wrapping, etc.
- Bakery – Searing or branding food and baking bread, cakes, pizzas, and biscuits.
How long does flame treatment last?
Depending on the material activation, the activation effect’s duration will change. After the therapy, the impact is at its peak before fading gradually. After a week, the contact angle may occasionally return to its pre-treatment state. It could eventually reach a level that is greater than it was before pre-treatment.
Ideally, pre-treatment should be followed immediately by manufacturing operations like coating or painting. Surface energy inks, which visibly display wetting or bunching of droplets, can be used to test components over time to determine how long they remain active.