Application of corona treatment and single coating in surface treatment

After the polymer surface is properly treated with corona, its wettability and adhesion can be changed, and the polymer matrix properties will not be affected. A typical processing device consists of a high voltage electrode and an inverting ground electrode. The counter electrode is generally a roller and serves as a guide for the object to be treated. After the applied voltage reaches the breakdown voltage of the air, the electrodes are discharged to generate atmospheric pressure plasma. The insulating coating on the high-voltage electrode and/or the anti-phase electrode can maintain a smooth, even discharge, avoiding conversion to a high-temperature arc.

The physical and chemical processes in the corona discharge process are very complex. The main reason is that the plasma induces various chemical reactions in the gas phase and on the surface of the polymer, and the chemical groups such as hydroxides, ketones, ethers, carbonic acids and esters are chemically bonded. Bonded to the polymer surface. These groups are polar, which increases the surface energy and ultimately improves the adhesion of the surface to printing inks, paints, adhesives, and various other coatings.

Corona treatment system

Recently, SOFTAL has launched a new CLN station developed specifically for narrow-format printing. This processing system is a convenient plug-and-play type, including the processing station itself, operating touch screens, easy-to-use generators and exhaust systems. The processing station was developed on the basis of the long-term use of the CLE series. The CLE series has now undergone a thorough redesign and optimization.

Softal's first multi-pole electrode

The strong structure and anti-corrosion materials used make the product durable and thanks to the new module structure, it is more convenient to maintain. Its compact cantilever structure makes it easy to install or retrofit into production equipment. The new CMB processing station for blown film lines and the well-known CR station for super-wide format processing are corona treatment devices developed for the blown film industry. They are based on the modular structure concept and are optimized for the application.

All SOFTAL corona processors are powered by state-of-the-art generators. The 7000 Series is a new generation of corona generators. Both hardware and software are innovative products. The 7000 Series has an output of 1kW to 4kW. The 6000 series single generator has an output of 6kW to 50kW. High power can be obtained by integrating multiple generators. All 6000 and 7000 series generators have well-known configurations of SOFTAL products, such as CCP automatic speed and width dependent power control, SCT for jitter processing, DCR with even power corona processing, and PROFI bus and CAN bus interfaces.

Reliability is the key

Reliable work under all environmental conditions is the key to economic production. Although modern general electromechanical technologies have been able to cope with harsh environmental conditions, the wet environment imposes special requirements on the corona treatment system. Failure to take appropriate preventive measures may result in unanticipated high-cost shutdowns. For a long time, working reliably in a humid environment is an important advantage of SOFTAL equipment. The main factor in achieving this success is the integration of mechanical and electrical aspects, which has now become the standard configuration of most SOFTAL devices. SOFTAL's solutions for wet environments have optional configurations for upgrading new systems and existing equipment so that they can be fully adapted to the environment. Optional configurations for wet environments include SCS, CSF, HAS and HHV. The SCS is a standard configuration of most SOFTAL corona generators. In combination with special ceramics used in corona electrodes, SCS forms the basis for SOFTAL's reliable operation in wet environments. The SCS ensures that corona treatment can be initiated easily and reliably even in the presence of condensate on high pressure components. Especially in an environment where the temperature and pressure drop from the outside to the inside, the CSF can prevent the recirculated humid air from condensing in the corona electrode when the device is turned off. Depending on the operating state, the CSF automatically controls the brake plate and exhaust fan in the exhaust system. In a very humid environment and after the corona device has been turned off for a long period of time, a large amount of condensed water will be generated on the stationary cold corona electrode during the starting process. The HAS effectively eliminates condensation by raising the temperature of the electrode to operating temperature prior to start-up. The HHV guarantees that even with very difficult production conditions, the components with high pressure in the electrodes are at a sufficiently high operating temperature to reliably avoid condensation.

Similar to solutions for wet environments, SOFTAL offers first-class technology for all surface treatment needs, from drastically reducing corona electrode contamination to rapid maintenance strategies, from non-standard materials handling, to special engineering designs and optimizing equipment combinations To the production line and process flow.

Corona treatment of plates and foam

The treatment of polymer sheet and foam is a rapidly growing field. Due to the special shape of these products, especially the large thickness, conventional corona treatment equipment cannot be used in many cases. Recently, SOFTAL has developed a new type of atmospheric pressure plasma source suitable for a variety of materials and structures that were previously unmanageable by corona treatment equipment. The compact system makes it easy to fit into existing production lines and can be scaled directly to larger processing widths, making it affordable for users. Compared to plasma injection systems, these plasma sources are extremely efficient and typically operate at a low power density of only 10 W/cm2. Dealing with a large width of a few meters is not only technically possible but also economically feasible. In addition to being easily adapted to the new structure, one of the main uses of this new plasma source is to handle thick foams. For open-cell foams, no preferential discharge channels are produced, and for closed-cell foams, no pinholes are generated. Moreover, the device has a low power requirement and can be used to handle temperature-sensitive foams. In addition, the new system is particularly suitable for honeycomb structures and reinforcing materials.

Single layer coating

In many applications in the printing and processing industry, it is necessary to use a tackified primer. Softal and Air Liquide have jointly developed AldyneTM, a cost-effective, environmentally friendly, atmospheric plasma process technology that replaces traditional liquid primers. Unlike corona treatment where the plasma process gas is ambient air, the AldyneTM process uses a gas that is stable and well-controlled. This controls the chemical reactions that occur within the plasma and at the polymer surface.

The resulting functionalized coating is only a single layer of molecular thickness, typically 0.3-0.4 nm. Since Aldyne Tm process does not use any liquid or solid matter, it does not accumulate residues, thus eliminating the costly cleaning process. Moreover, in the AldyneTm process, there is no need for a drying step and there are no problems associated with the removal of organic solvents. Molecular coating can be adjusted according to the processing technology. For example, amides, imides, and amino groups can impart good adhesion to materials such as aqueous, solvent, and UV drying inks, paints, and adhesives. AldyneTm is an online technology that can be easily incorporated into existing production lines. Its main components are a specially designed plasma source (which can control the plasma gas at the ppm level), a gas delivery system and a complete, fully automated process control system.