UV Cure is a radiation curing process and belongs to the group of chemical curing processes. Chemical curing involves solid film formation through cross-linking and polymerization, respectively – this process is irreversible.

Photochemically induced polymerization by means of UV-Radiation is termed UV Cure. Depending on the polymerization reaction type two curing processes can be distinguished. 

Typical for inkjet:

• Radical Cure
  Radical cure represents polymerization of alkene group containing (unsaturated) molecules (acrylates, vinyl ethers). It runs as a free radical chain reaction and is initiated by radical forming photoinitiators or by energy transferring photosensitizers. Radical cure is sensitive to oxygen (O₂).

Special Characteristics:

• This film forming process is irreversible and represents a polymerization. The polymer formed is insoluble.
• Polymerization runs within a split second, provided a UV light source of sufficient intensity is used.
• Polymerization occurs only while exposed to UV-Light.
• Radical cure is subject to oxygen (O₂) inhibition.

Non-typical for inkjet:

• Ionic (Cationic) Cure
  ationic cure represents cationic polymerization of oxirane group containing molecules (epoxides) or unsaturated vinyl ethers and is initiated by cation forming photoinitiators.

Special Characteristics:

• This film forming process is irreversible and creates an insoluble polymer.
• Depending on the UV light source used, cationic polymerization runs fast but, as a general rule, it runs slower than radical polymerization.
• The polymerization is triggered by UV light and runs, once initiated, without further light exposure as quantitative polymerization.
• Cationic cure is not subject to oxygen (O₂) inhibition.

Tritron offers UV curing inkjet inks, called HD Photon, for FUJIFILM Dimatix (former SPECTRA), XAAR and Konica Minolta printheads to OEM partners. HD Photon inks are available as process colors including light tones as well as spot colors.