Authors Gedan-Smolka, M. ; Lehmann, F. ; Lehmann, D.
Title New Catalysts for the Low Temperature Curing of Uretdione Powder Coatings
Date 11.06.2002
Number 9908
Abstract Dialkyl-tin-di-carboxylates, dialkyl-tin-di-alkoholates and metall--di-carbonylic compounds were<br />obtained as effective catalysts for the reaction of uretdione groups with OH- groups in melt. Using low<br />molecular weight model systems and zinc(II)-acetylacetonate as catalyst a reduction of the reaction<br />maximum Tmax of about 90 K compared with the non catalyzed system could be detected by non-isothermal<br />DSC measurements. The mechanism of the reaction between uretdione and OH-groups was studied by the<br />use of temperature dependent FTIR measurements, 1H and 13C NMR spectroscopy. For isothermal curing at<br />temperatures below 160°C a new reaction mechanism was proved for reactions in melt. The catalayzed<br />reaction between uretdione and OH-groups lead to allophanate structures and showed a high selectivity.<br />The results were successfully transfered into reactive polymeric models. Initial studies of film properties<br />obtained with the catalyzed reaction were evaluated using powder coating model samples.
Publisher International Journal of Coatings Science (Online-Journal)
Citation International Journal of Coatings Science (Online-Journal) (2002)

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