UV ABC's - What Is the Difference Between UVA, UVB, UVC and UVV

UV curing is a photochemical process where different types of UV wavelengths are used to cure inks, coatings, sealants and adhesives. The low temperature, photochemical reaction eliminates the need for solvents and drying time, making it a faster process than two-part adhesives. The UV ranges used for UV curing are A, B, C, and V.
 
Each UV has a different wavelength range that determines how deeply it can penetrate the substrate. The appropriate UV is chosen for an application based on the substrate being used and the desired curing effect:
  • UVC is a shortwave ultraviolet used for top surface curing that creates surface hardness and abrasion resistance
  • UVB is a midwave ultraviolet capable of deep penetration curing that creates coating and adhesive toughness
  • UVA is a longwave ultraviolet used to cure the deepest layers and provides adhesion and cross linking
  • UVV is a visible ultraviolet that is used for silver pigment and Titanium Dioxide curing, as well as adhesion 

Understanding the Ultraviolet Spectrum

Ultraviolet light UVA, UVB and UVC all fall within the ultraviolet spectrum, meaning their wavelengths are not visible. UVV produces a visible wave and has the longest UV wavelength utilized in general UV curing processes. Each UV wavelength is measured in nanometers and the length determines how far it can penetrate the ink, coating, or adhesive on the substrate surface. Certain UV wavelengths can also be used for sterilization and inspection processes.

UVA Wavelengths

The wavelength for UVA spans 320 nm to 395 nm, making it the longest UV wavelength. UVA is used for general UV curing and is responsible for most of the adhesion properties for the UV formulations. Common uses for UVA include:
  • Curing inks, coatings and adhesives
  • UV inspection
  • UV fluorescing 

UVB Wavelengths

UVB has a mid-range wavelength measuring 280 nm to 320 nm and works with many of the photo initiators in use today. Like UVA, it is used for curing coatings, adhesives and inks but is also highly utilized for UV applications involving:
  • Disinfection
  • Sterilization 

UVC Wavelengths

The shortest and weakest wavelength is UVC, which measures 200 to 280 nm. It delivers powerful output in the 250 to 260 nm range but does not travel well in air. Since oxygen can block the UVC, many applications involve the use of a nitrogen purge environment. UVC gives coatings their scratch resistant properties and is utilized for a wide range of applications including:
  • Clear top coating of paper and plastics
  • Hard coating of optical and automotive lenses
  • Disinfection and germicidal applications
  • DNA cross linking
  • Surface modification 

UVV Wavelengths

UVV is a visible wavelength that spans from 395 nm to 455 nm. It is used to cure the “deepest area” on most UV/Visible formulations and is responsible for the adhesion properties of those formulas. UVV works well with white and silver conductive pigments and is frequently used for the following curing processes:
  • Silver conductive inks
  • Coatings with TiO2 pigments
  • Adhesives and deep potting compounds

Learn more about UV Curing Options

Contact Doctor UV to learn more about UV curing options or to request a quote for our UV curing services.