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In many cases, refining smooth film surfaces causes large difficulties, because there is insufficient adhesion for printing, sticking or depositing metals. The chemical-physical properties of the surface are changed to alter this situation, such as pretreating with a corona system, for example. Against the background of continually increasing quality requirements on the surface characteristics, kalwar developed the calvasol® technology. Using this process, reactive liquid and/or gaseous substances are applied as a special coating to film surfaces in an inline process. An aerosol is brought into the corona discharge field using an air or or gas flow, which is then deposited onto the plastic surface.
A reactive mechanism is triggered by the corona discharge, which causes a chemical change on the film surface. Depending on the type of liquid and the aerosol carrier gas used, active centres are formed on the plastic surface being treated in the form of functional groups and radicals, which act as reaction partners for the substances being applied. Polymerisable coats can also be applied using this method.
The application of extremely thin layers in the nano range is often sufficient to alter the surface characteristics of a film, such as antistatic, barrier behaviour and adhesion properties, in the desired manner. If the aerosol substance is not fed through the corona discharge field, then laminar air flows are produced between the supporting roller and corona electrodes at a velocity of just 1 m/min, which prevent the substances from fixing on the surface.
The calvasol® process opens up new possibilities for pretreatment and coating technology. Even thin films of up to 10 m working width can be refined with this process at speeds of over 400 m/min. PET film has a surface resistance of ›1013 ohms. Applying an antistatic with calvasol® reduces the surface resistance down to 108 ohms.
Coating OPP film with a adhesion promoter is an important refining stage. If the film is just pretreated with corona, it loses its initially high adhesive strength very quickly. An improved adhesion value of >60dyn over month was achieved using the calvasol® functionalisation.
The calvasol® system is a highly effective and economic coating process, because the substances are applied in the nano range and consumption is correspondingly low. In addition, almost all soluble coating substances, including those suitable for food contact areas, can be processed.
The newest calvasol® Generation allows the substantial saving of energy, additives and functional chemicals proportional to the wet coating or varnishing. This is not only very good for the environment but also reduces the cost of production in case of energy for example by more than 90%! The substantial reduce of the carbon footprint results in the avaliability of federal state subsidies.
We gladly calculate your individual austerity plan for your production. You will be surprised about the substantial savings not only in energy but also by more effective production capacity utilisation and reduced additive- or lacquer consumption when producing with calvasol®.
Request further and detailed information and get in contact with us today.