Corona treatment of metals boosts the anchoring of inks (mainly in screen or digital printing applications) and polyurethane foams for thermal and acoustic insulation.
We analyse the corona treatment of aluminium sheets in the production of sandwich panels prior to the application of polyurethane insulation foam.
To achieve the best results, we recommend removing any dust, oil or other processing residues and treating both the top and bottom sheets of the panels.
Main applications for sandwich panels
- Roofs, fronts and ceilings of industrial buildings, commercial buildings, residential buildings, warehouses and distribution centres
- Polyurethane components and foams for thermal and acoustic insulation
- Interior partitions
- Cold rooms and storage facilities
- Insulated truck or van walls
- Boats and offshore platforms
- Photovoltaic, solar thermal and wind energy systems
- Greenhouses and storage facilities for agricultural products.
The advantages
Corona treatment of sandwich panels:
- Allows polyurethane foams to adhere firmly even when applied in very thin layers (material savings) and on the most difficult surfaces
- Prevents the polyurethane foam from peeling off at certain points, thus preventing the formation of air bubbles that compromise the insulating properties
- Improves mechanical strength and durability by protecting against weathering, rust and corrosion
- Prevents cracking, delamination or separation of layers.
Ferrarini & Benelli has been manufacturing and selling corona treatment equipment for this specific application for 25 years and is the partner of choice in this field.
The consolidation of the use of corona treatment for this type of application at European level was the approval of the Montreal Protocol, which was aimed at drastically reducing the use of Freon gas as an expanding agent in polyurethane foams. In 2000, the European Union introduced the EC Regulation 2037/2000, which banned the production, import and use of Freon.
The elimination of Freon, which acted as a bonding agent, created the problem of polyurethane foam not adhering to metal. To solve this problem, Ferrarini & Benelli developed and designed a corona treatment system for sheet metal to increase foam adhesion.
Aluminium sheets
Sheet produced by rolling mills may have oily residues (lubricants or oils are used to reduce friction and improve the quality of the finished product). Corona treatment eliminates oily residues and prevents adhesion problems with paints, inks or adhesives.
Painted/coated sheets
Pre-painted or coated sheets have relatively smooth surfaces and low surface tension, which makes adhesion of foam materials such as polyurethane foams difficult.
Corona treatment, by increasing the surface tension, makes the sheet surface more suitable for forming a stable chemical and physical bond with the adhesive or foam.