Lacquer Curing Performance

The curing state of lacquers and adhesives is an important parameter not only for the functionality and technical suitabilities of thin filmes but also for legislative re¬commendations concerning the potential of global and specific migrates in contact with food. Therefore, the evaluation of sufficient curing states is necessary for the set up and the control of coating production processes especially during and after the modifica¬tion of the process parameters e.g. at upspeeding of lines. In addition quality assu¬rance and claim management need reliable methods to describe the lacquer proper¬ties. Existing test procedures as the determination of the solvent retention, organic solvent resistance (e.g. MEK-double-rub-test) or mechanical testing exhibit results of low certainty.

The preproject work aims to a replacement of insufficient methods by the application of modern techniques, which are capable to give integral results from direct measu¬rements of the film properties on the substrate. New approaches of dielectric measu¬rement principles will be compared with the results of traditional methods including thermoanalytical and other spectroscopic methods applied today.

In packaging the use of laquers is characterized by very different application profiles ranging from flexible packaging materials as laminated metal foils to the field of rigid containers based on steel or aluminium. The requirement profiles are met by diffe¬rent classes of coating systems e.g. physical drying ones or polymerizing by heat curing. The results coming out of the investigation of a typical coating systems are used to set up a further AiF-project reflecting the whole application scope of lacquers and adhesives in packaging.