Plasma treatment

Atmospheric plasma is a process that uses an ionized gas (plasma) to modify the surface of polymers and other substrates. Plasma is created by applying very high energy to a gas - in the specific case of atmospheric plasma, the air we breathe - transforming it into a collection of charged particles. These particles come into contact with the surface being treated, improving adhesion or removing contaminants.

By way of indication, and not exhaustively, we list some substrates and applications:

• Polyethylene (in bottles, containers, components of various shapes)
• Polypropylene (automotive parts and medical devices)
• Polycarbonate (lenses, aircraft parts and electrical equipment)
• ABS (molds, automotive parts and toys)
• Polyamides (cables, mechanical parts and industrial components)
• PVC (profiles for furniture, profiles for window frames)

Plasma can also be used to process: metals, glass, ceramics, textiles and composites (an example of a composite is the combination of a shoe upper and sole).

Compared to other types of treatment, plasma treatment is:

• Green: eliminates the need to use hazardous chemicals and solvents, reducing waste and environmental impact
• Precise: Allows very small areas or surface details to be treated without affecting areas that do not need treatment. This level of precision is difficult to achieve with traditional chemical treatments.
• Effective at low temperatures: useful for heat-sensitive substrates such as polymers
• Fast: fast process that can be easily integrated into production lines without downtime
• Safe: plasma treatment eliminates the risk of operator exposure to hazardous chemicals and toxic agents
• Economically sustainable: reduces costs associated with chemical waste disposal and consumes little energy

• Treatment power: Plasma power affects the density of charged particles and their energy, thus determining their effectiveness.
• Exposure time: exposure to the plasma discharge for an appropriate amount of time is critical.
• Distance between the plasma discharge and the treated surface: this distance affects the uniformity and intensity of the treatment.
• Temperature: the temperature of the substrate and the working environment affect the process and the results of the surface treatment.

Yes, atmospheric plasma treatment is particularly effective for treating objects with irregular geometries. In fact, plasma penetrates hard-to-reach areas and treats irregular surfaces uniformly, saving considerable time and energy. The nozzle may also be mounted on a collaborative robot, ensuring maximum precision in the treatment of details.

The duration of the effect of plasma treatment on plastic surfaces can vary depending on the type of polymer (or other substrate being treated) and the environmental conditions to which it is exposed. Over time, as the substrate is exposed to atmospheric factors and additives migrate to the surface, it is best to perform the treatment directly in-line.

Plasma treatment is safe and will not damage the treated substrate if performed correctly, in line with the instructions in the user manual provided. Periodic maintenance of the treatment system will prevent risks.

Before delivering the plasma system, Ferrarini & Benelli offers a laboratory service for testing the customer's substrate samples. This way, it is possible to determine all the correct parameters in order to optimize the treatment and prevent damage to the substrate.

Done correctly, plasma treatment, in addition to improving adhesion, optimizes the quality of the finished product by improving the treated substrate’s resistance to abrasion, scratches and adverse environmental conditions (such as extreme temperature changes) and by optimizing surface cleanliness.

Yes, atmospheric plasma treatment is considered safe for workers, provided that proper safety precautions are taken, such as the use of PPE and routine maintenance of the equipment. Unlike corona treatment, plasma treatment does not produce ozone.

• Automotive: to improve adhesion of seals, coatings and paints, and to clean surfaces
• Aerospace: Surface cleaning and activation of substrates used in aircrafts
• Medical: Sterilization and surface activation of medical devices
• Packaging: to improve adhesion of inks and adhesives on folding paste lines in carton production
• Textile: to improve adhesion of dyes and coatings to fabrics
• Printing: to improve wettability and adhesion of inks on difficult-to-print surfaces, including allowing the use of water-based, solvent-free inks or digital printing inks

Yes, plasma treatment can contribute to the sustainability of the manufacturing process because it eliminates the use of solvents and toxic chemicals, uses less energy than chemical treatments, and generates no waste for disposal because it does not produce harmful chemical by-products.

To determine if plasma treatment is appropriate for a particular substrate or production process, it is important to conduct a preliminary test in the laboratory to evaluate the substrate properties, define the treatment objectives, and ensure that the system can be integrated without disrupting the existing production process.

Atmospheric plasma operates at atmospheric pressure, so there is no need to maintain a low-pressure environment, as is the case with vacuum plasma, which requires complex and energy-intensive vacuum systems. Very good results can be achieved with only a few kilowatt hours.