Nanoparticle Photoinitiators for UV Curing Printing Inks, Varnishes and Glues

Conventionally, the curing or rather drying of printing inks, varnishes and glues is based on the evaporation of solvents. As an alternative, the use of photoinitiators has been established. These substances enable a fast and controlled curing without the help of solvents by the use of UV radiation. A disadvantage of the conventional molecular photoinitiators (e.g. Igaracure 651 or Darocur 1173) is that they are toxic for human beings due to their high chemical reactivity. During the UV curing process only about 10% of the substance is converted. The remaining 90 % can diffuse or migrate through the cured matrix. This causes problems, especially for the food industry because the toxic substances can merge into the food by different means.

The completely new photoinitiators for printing inks, varnishes and glues presented here are based on photo catalytic functionalized semiconductor nanoparticles. The photo catalytic activity could be increased considerably through a synergetic effect between the nanoparticle and the mediator molecule. A single nanoparticle is 700 times more efficient than a classic molecular initiator molecule. Due to its mass the particle cannot migrate through the cured matrix. The molecules which have not been converted by UV irradiation stay attached to the immobilized nanoparticle. The new photoinitiators as compared to the commercial initiators offer the opportunity to cure printing inks, varnishes and glues very fast and without the contamination of the environment.

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Universität des Saarlandes Wissens- und Technologietransfer GmbH PatentVerwertungsAgentur der saarländischen Hochschulen
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Contact
Dr. Annekathrin Seifert (Dipl.-Chem.), Dipl.-Kfm. Axel Koch (MBA), Dr. Hauke Studier (Dipl.-Phys.)