What is a UV curing system?
Traditionally, printing inks,coatings or adhesives were dried with heat, and in some cases this is still done today.UV curing is a photochemical process in which high-intensity ultraviolet light is used to instantly cure or “dry” inks, coatings or adhesives. The UV curing system is built around an ultraviolet irradiation unit for curing resins that set under UV light.
What is Ultraviolet Light?
Ultraviolet light exists just below visible light in the electromagnetic spectrum. UV light ranges in wavelength from 100 to 400 nanometers and cannot be detected by the human eye. The UV spectrum can also be broken down further into three groups: UVA (315-400 nm), UVB (280-315 nm) and UVC (100-280 nm). UVB and UVC are higher energy and are generated from high intensity sources such as medium pressure mercury vapor lamps. Most photoinitiators absorb in the UVA and UVB region. For low intensity curing applications, fluorescent “black lights” are a convenient source of UVA.
Principle of the UV curing system
Ultraviolet rays emitted from the lamp induce a photochemical polymerization reaction in inks, paints,adhesives, and other products that contain photosensitive materials such as prepolymers, monomers, photopolymerization initiators, and pigments that cures these products instantaneously.
UV curing process ：
• UV curing process uses inks and varnish with photoinitiators
• Photoinitiators are reactive to a specific bandwidth and intensity of UV light
• Photoinitiators split by UV light into two free radicals
• Free radicales try to couple with the binders
• Cross links are formed