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Progress in the development of cobalt‐free drier systems
Author(s) -
Bieleman Johan H.
Publication year - 2002
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/1521-3900(200209)187:1<811::aid-masy811>3.0.co;2-l
Subject(s) - autoxidation , cobalt , manganese , catalysis , polymerization , chemistry , transition metal , organic chemistry , polymer chemistry , coating , polymer
Driers are used in air‐drying coating systems to catalyze the polymerization process. Cobalt‐carboxylates are the most widely used driers. However, cobalt compounds may indirectly be implicated as carcinogen suspects as a result of studies in the U.S.A. in the national toxicology program using cobalt sulphate heptahydrate. Hence, Germany is no longer granting the Blue Angel award to cobalt‐containing paints. Other transition metal carboxylates such as based on manganese or iron show much lower catalytic effects and cannot equalize cobalt as a catalyst in autoxidation polymerization reactions. The effect of various organic chelating ligands on the catalytic properties of manganese in autoxidation processes was investigated experimentally in air‐drying paints. The activity of manganese is strongly effected by organic ligands. New manganese based coordination compounds enable the formulation of Co‐free air‐drying paints, which show good drying performances and improved color retention.