Photoinitiator free UV-curing DirectCure


The direct initiation of polymerization and crosslinking of acrylates by high-energy photons  is called photoinitiator free UV-curing. The acrylate molecule itself forms the “chromophor” needed for the radical formation. Patent pending.



photoinitiator free uv curing directcure

Benefits of photoinitiator-free UV curing


1. Highest output from direct excitation of the acrylate double bond:
  • Improvement of chemical and temperature resistance
  • Better mechanical properties
  • Better light and weathering stabilitiy.
  • Crosslinking of fixed systems (UV water-based coatings) and post-crosslinking of polymers with residual double bonds efficient possible
  • Crosslinking density higher than with EBH (Electron Beam Hardening)
  • no negative influence to the substrate as EB on Paper, PVC, etc
2.  No or very low (<0.5%) concentrations of photoinitiators required, resulting in:
  • Significant reduction of migration and VOC (Volatile Organic Compounds) emission
  • No “UV odor”
  • Limit values for migration from food packaging can be adhered to.
  • Migration and VOC emission similar to EBH at doses of 30 to 40 kGy.
3. Oxygen sensitivity of UV curing greatly reduced:
  • Operation of UV systems up to 1000 ppm residual oxygen possible.
  • Nitrogen production through PSA (Pressure Swing Adsorption) as an alternative to vaporization possible.

Food packaging, Furniture, Floor, Automotive

DirectCure compared to the Electron Beam Hardening (EBH): Extractable acrylates from offset printing.

DirectCure compared to the Electron Beam Hardening (EBH): Extractable acrylates from offset printing.

The EU Regulation of 2016 calls for a specific migration limit (SML) of <10μg/kg (10 ppb) for food packaging starting at 1 January 2016. This limit is well below what we have using our method.

An upgrading of existing installations is possible. Contact us – we will find the right solution for your application.


IOT GmbH filed a patent for the process of the photoinitiator-free UV curing.

Photoinitiator free UV-curing - DirectCure - Iot Leipzig

IOT GmbH Leipzig

Innovative Surface Technologies


UV - Technik
Plasma- und Ionenstrahltechnik


IOT Innovative Oberflächentechnologien GmbH
Wissenschaftspark Leipzig, Gebäude 33.0
Permoserstraße 15

04318 Leipzig
Phone +49 341 23823 100 
Fax +49 341 23823 199