UV-curing varnishes
Product description
KNEHO UV varnishes are coating systems based on chemical reactions involving unsaturated polyesters or polyacrylates, or combinations of the two. The chemical reaction is initiated by photoinitiators that become active under ultraviolet radiation of specific wavelengths.
Using UV varnishes enables rational, non-polluting, and economical production processes. The UV varnish category is optimized for the lowest possible solvent content, often achieving a 100% solid content. This aspect is increasingly important given the legal limitations on volatile organic solvents and air pollution.
Properties:
- Fast and efficient production processes
- Minimal or zero content of volatile organic solvents
- Instant curing under UV radiation
- Superior resistance to wear and scratching
- Material savings through efficient application
- Available in clear or colored versions
Optimal application
UV finishing systems are particularly efficient when used in roller application equipment. In such systems, a high-quality lacquer film is obtained with minimal material consumption. At the same time, UV varnishes are also widely used in spray application systems.
Variety of finishes
The UV varnishes produced by KNEHO are available in clear or colored versions, with different gloss levels and quality grades, suitable for open- or closed-pore finishes, according to the client’s preferences.
Application and curing process
Surface preparation
The surface must be perfectly clean, dry, and properly sanded. For optimal results, it is recommended to apply a dedicated UV primer that ensures optimal adhesion of subsequent layers. The wood’s moisture content should be controlled, ideally between 8–12%.
Application methods
UV varnishes can be applied using various methods, the most efficient being roller application for flat surfaces and spraying for complex shapes. The thickness of the applied layer must be precisely controlled to ensure complete curing. For industrial applications, automated coating lines are used.
UV curing process
After application, the varnish is exposed to ultraviolet radiation of a specific wavelength, which activates the photoinitiators. These trigger the polymerization reaction that transforms the liquid varnish into a solid film within seconds. The UV radiation intensity and conveyor speed under the UV lamps must be optimized for each type of varnish.