UV curing of paints and varnishes is an established, fast and energy-efficient method for cross-linking reactive paint and varnish systems. It has proven itself in various sectors such as wood processing, surface coating and the printing industry. Traditionally, photoinitiators are used to absorb UV light, generate radicals and thus start the curing process by converting the C=C double bond. This technology enables the production of highly resistant surfaces that meet the highest customer requirements in terms of both appearance and durability - while at the same time optimizing cost efficiency and compliance with important environmental regulations
Oxygen inhibition reduces the efficiency of UV curing by slowing down the production speed and affecting the quality of the coating. However, traditional solutions such as inerting or increased addition of photoinitiators bring new challenges: higher costs, yellowing, unpleasant odors and emissions, which can be particularly problematic in sensitive areas such as the production of kitchen surfaces.
Photoinitiators are a key component of the conventional UV curing process. They absorb UV light and generate radicals that split the C=C double bond and thus initiate the curing process. However, the increasing restriction in the availability of photoinitiators poses a challenge for the paint and coatings industry. This is mainly due to stricter environmental regulations, such as the REACH regulation, as well as bottlenecks in production, particularly in China. Some photoinitiators could be banned altogether in the future. In addition, these substances can have odor and migration potential, which makes them difficult to use in sensitive areas such as the food industry.
In view of supply bottlenecks, stricter regulatory requirements and the elimination of some photoinitiators, the question arose as to whether the UV polymerization process could be implemented without or with a greatly reduced photoinitiator content - while at the same time avoiding oxygen inhibition and without and without the use of an inert environment.
Our UV experts have been working on innovative UV solutions to minimize the environmental impact, not only because of the discussions about sustainability, rising energy prices and the reduction of the CO2 footprint. They have developed innovative approaches to meet the growing demand for sustainable solutions. The solution for this is a UV curing process that works by directly cross-linking the C=C double bonds. To directly cleave these bonds, a light energy is required that exceeds the binding energy of the C=C double bond.
As UV light with a shorter wavelength is more energy-intensive, the light spectrum of the UV system was specifically shifted to the short-wave UVC range and additionally amplified there. The main measures for this are. The main measures included:
The FREEcure system is the solution for 100% UV systems and aqueous UV systems. The following aspects were taken into account when formulating the UV systems:
Discover how the FREEcure system not only reduces the number of lamps for dose-intensive applications, but also paves the way for more sustainable and efficient UV curing. Set new standards in UV curing with FREEcure and shape the future of your production.
