Manganese and Iron Catalysts in Alkyd Paints and Coatings

Abstract

Many paint, ink and coating formulations contain alkyd-based resins which cure via autoxidation mechanisms. Whilst cobalt-soaps have been used for many decades, there is a continuing and accelerating desire by paint companies to develop alternatives for the cobalt soaps, due to likely classification as carcinogens under the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) legislation. Alternative driers, for example manganese and iron soaps, have been applied for this purpose. However, relatively poor curing capabilities make it necessary to increase the level of metal salts to such a level that often coloring of the paint formulation occurs. More recent developments include the application of manganese and iron complexes with a variety of organic ligands. This review will discuss the chemistry of alkyd resin curing, the applications and reactions of cobalt-soaps as curing agents, and, subsequently, the paint drying aspects and mechanisms of (model) alkyd curing using manganese and iron catalysts.

Catalytic Behaviors of CoII and MnII Compounds Bearing α-Diimine Ligands for Oxidative Polymerization or Drying Oils

“…In the oxidative polymerization process, the apparent kinetic constants, which were related to the evolution of the viscosity, obtained for 1 and 2 show that the cobalt complex (1) is more active than the manganese complex (2), in accordance with previously reported results. 2,4,11 As can be observed from Figures 3 and 4, the modifications of cobalt 2-ethylhexanoate (1) by a, b and c diminished its catalytic effect. However, for the manganese carboxylate modified by the nitrogen ligands (2a, 2b and 2c), the catalytic effect was improved compared to that of the carboxylate (2), and in some cases, this activity was better than the cobalt carboxylate (1).…”

“…The increase of the catalytic activity of manganese 2-ethylhexanoate (2) in the presence of the bipyridyl ligand has already been reported, and in this example, the carboxylates were not removed from the metal center. 7,10,11,25,26 In this context, we suggest that the addition of the nitrogen ligands must stabilize both type of complexes. Nevertheless, in the case of the modified Co II complexes the coordination of nitrogen ligands provide the formation of very stable complexes that compromise their catalytic activity for oxidative polymerization reaction of drying oils.…”

“…1,6,7 One strategy to raise the catalytic performance of these catalytic systems is based on a modification of their coordination sphere, employing nitrogen ligands, since their ability to modify the steric and electronic properties can be used to change the behavior of the complexes for oxidative polymerization and to improve the compatibility of the driers in the reaction system. 1,[6][7][8][9][10][11] In former work, it was observed that the addition of nitrogen ligands in situ improved the reaction rate of the oxidative polymerization, in the presence of classical catalysts. 10 In order to extend the alternatives, in this work is established the influence of diverse nitrogen ligands on the catalytic performances of metal carboxylates in oxidative polymerization processes.…”

Komparasi Kualitas Cat Alkid Menggunakan Pelarut Hasil Pirolisis Limbah Plastik Polietilen Dengan Pelarut di Industri Cat

“…Berdasarkan kandungan asam lemak yang digunakan, resin alkid dibedakan menjadi 3 jenis yaitu: Long Oil Alkyd (LOA) mengandung lebih dari 56% asam lemak, Medium Oil Alkyd (MOA) mengandung 46-55% asam lemak dan Short Oil Alkyd (SOA) mengandung kurang dari 35 45% asam lemak (Ploeger dan Chiantore 2012). Penelitian cat alkid selama ini banyak dilakukan pada bagian modifikasi resin alkid seperti modifikasi katalis mangan dan besi pada pembuatan resin alkid (Hage, de Boer, dan Maaijen 2016), sintesis resin alkid menggunakan katalis asam polibasa (Ilkhani 2012), dan resin alkid termodifikasi minyak jagung dengan asam phtalat anhidrat (Heriyanto et al 2011).…”

Theoretical and Experimental Study of Light-assisted Polymerization by Multimechanism Action

“…In the autoxidation, the Co salts mainly catalyze the decomposition of hydroperoxides to generate alkoxy radicals (RO · ), leading to polymerization (Haber and Weiss reaction). The details of the mechanism have not been clearly understood thus far; for specifics, the reader is referred to the original literature234. However, there is a general consensus that hydrogen abstraction (i.e., dehydrogenation) is the rate-determining step in this autoxidation.…”