UV direct cross-linking

Reactivity without initiators

In traditional UV curing process, photo initiators are mixed into the varnish. Photo initiators are of considerable importance as they absorb UV radiation and generate radicals, which initiate UV polymerisation and thus the curing process by converting the C=C double bond.

The low availability of photo initiators poses a challenge for the ink and varnish industry. The reason for the restriction of photo initiators is increased environmental regulation in China, the main production country for photo initiators and their raw materials. Within the framework of the REACH regulation (REACH stands for Registration, Evaluation, Authorisation and Restriction of Chemicals), it is conceivable that certain photo initiator types could be reclassified and therefore no longer available in future. In addition, photo initiators have the potential for odours and migration. As a result, UV processes are excluded for applications or can only be implemented with great effort.

The increased performance in the UV-C up to 280 nm was achieved by the following measures:

  • Adaptation and optimisation of the plasma technology
  • Use of special materials for the lamps, reflectors and pass filters
  • Optimisation of the electronic controls

Our FREEcure is not only suitable for 100% UV systems, but also for water borne UV systems. When formulating the UV systems, the following aspects were taken into account:

  • No photo initiators
  • Chemical composition of the binding agent
  • Functionality of the binding agent
  • Amine modification for effective suppression of oxygen inhibition
  • Physical surface drying of aqueous UV dispersions

More about Freecure


  • Environmentally friendly curing
  • No photo initiators
  • Beneficial from a human sensory point of view
  • Energy-efficient
  • Extremely short curing times
  • Simple process
  • High cost-efficiency
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