FREEcure expands the possibilities of industrial UV curing through a particularly high proportion of short-wave UV radiation. With suitable formulations, the water-cooled UV system enables curing without photoinitiators or with a significantly reduced photoinitiator content.
This makes FREEcure an attractive process option for printing inks, coatings and finishes – including applications in packaging printing and the wood and wood-based materials industry.
FREEcure is based on the proven BLK system and uses a specially designed medium-pressure UV lamp with an increased UVC output. In formulations specifically designed for this purpose, the short-wave spectral range in particular supports direct photochemical initiation and crosslinking.
This allows suitable coating and ink systems to be formulated without photoinitiators or with a reduced photoinitiator content compared with conventional formulations.
Whether completely photoinitiator-free curing is possible depends on the specific formulation and process conditions.
Photoinitiators and their by-products can be relevant in migration-sensitive applications. By enabling photoinitiator-free or reduced-photoinitiator formulations, FREEcure can help reduce corresponding potential sources of migration.
This makes the technology particularly relevant for applications where the composition and migration of the substances used play an important role.
However, actual migration and suitability for a specific packaging application depend on the entire system – including the ink or coating, substrate, layer thickness, process conditions and degree of cure achieved – and must be assessed for each individual application.
FREEcure can be used for both 100% UV systems and appropriately designed water-based UV systems.
For photoinitiator-free or reduced-photoinitiator curing, the chemical composition and functionality of the binder are particularly important. A suitable formulation can also help limit oxygen inhibition at the surface.
For water-based UV dispersions, physical drying before or in combination with UV curing must also be taken into account.
FREEcure combines the BLK system with a medium-pressure UV lamp and a system concept designed for high UVC output. This provides a high proportion of short-wave UV radiation for the curing reaction.
In suitable applications, this can reduce the number of UV units required. Fewer installed units can also offer the potential for reduced space requirements as well as lower energy, maintenance and spare parts costs.
The actual savings achievable depend on the formulation, layer thickness, substrate, production speed, required degree of cure and the respective reference system.
In high-speed roller coating lines in the wood and wood-based materials industry, FREEcure can help reduce the number of UV units required.
For 100% UV systems, depending on the formulation and process, a reduced photoinitiator content can be beneficial in achieving the desired production speed with as few UV units as possible.
For suitable applications, FREEcure process speeds of 30 to 50 m/min per unit have been reported. Depending on the application, two to three units may therefore be sufficient for high-speed roller coating lines.
For thicker coating layers, a combination with LED UV systems may also be beneficial. The appropriate system configuration should be matched to the coating, layer thickness, substrate, production speed and required degree of cure.
Is FREEcure suitable for your UV process? Test your application at our IST Campus under real-world conditions.
