Performance of Manganese(III) Acetylacetonate in Solvent-Borne and High-Solid Alkyd Formulations

Abstract

This paper reports a strong drying activity of manganese(III) acetylacetonate. It is documented on several solvent-borne and high-solid alkyd binders. Solubility problems, which often appear upon application of new primary driers, were overcome by use of dimethyl sulfoxide. Interestingly, intense coloration of the drier does not influence the transparent paint films due to in situ reduction to manganese(II) as evidenced by colorimetric measurements. Kinetics of the autoxidation process was investigated by infrared and Raman spectroscopy. For selected formulation, the effect of film thickness on through drying was estimated by infrared spectroscopy using attenuated total reflection sampling technique.

Helmet Phthalocyaninato Iron Complex as a Primary Drier for Alkyd Paints

“…The metal concentration 0.003 wt.% seems to be the optimal dosage for Fe-diiPc in the absence of secondary driers; these can strongly influence the process of through drying. Commercial Co-2EH, used as the reference, shows optimal performance at considerably higher dosage (0.1 wt.%), which is in line with recommendation of suppliers and literature data [ 17 ]. At this concentration of Co-2EH, τ 2 is comparable but τ 4 is significantly longer than that observed for Fe-diiPc at 0.003 wt.%.…”

“…In line with previous studies, the peroxidation step was treated as a reaction of pseudo-first order because the concentration of molecular oxygen is expected to be constant upon the curing process [ 17 , 25 ]. Estimated maximal rate coefficients ( k max ), induction times ( t ind ) and half-lives ( t 1/2 ) for formulations Fe-diiPc/S471 and Co-2EH/S471 are listed in Table 5 .…”

“…Figure 6 displays the development of the pseudo-first order rate coefficient on the allylic moiety conversion for two driers under study, together with two other promising primary driers, namely Borchi OXY-Coat and Mn(acac) 3 , which will be helpful for better understanding of the phenomenon. We note that the kinetic parameters for Borchi OXY-Coat are given in Table S5 in the Supplementary Materials , while those for Mn(acac) 3 have been published elsewhere [ 17 ].…”

“…The experiments were conducted in 24 h mode with a weighted (5 g) needle. The evaluation of set-to-touch time (τ 1 ), tack-free time (τ 2 ), dry-hard time (τ 3 ) and dry-through time (τ 4 ) is described in detail in our previous work [ 17 ]. Two independent measurements were performed for each formulation; averaged values are reported.…”

“…Commercial cobalt-free systems usually involve manganese(II) carboxylates [ 15 ] or their mixtures with N -chelators (e.g., bipyridine) [ 16 ], but these systems suffer from discoloration and a low activity at adverse climatic conditions [ 15 ]. Promising drying characteristics are further reported for manganese(III) acetylacetonate [ 17 ], manganese complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane [ 14 ], oxidovanadium(IV) carboxylates [ 18 , 19 ], oxidovanadium(IV) acetylacetonates [ 20 , 21 , 22 ], and oxidovanadium(V) dithiocarbamates [ 23 ]. The field of iron-based primary driers is currently focused mainly on commercial iron bispidine complex, known under the trademark Borchi OXY-Coat, which performs at very low concentrations compared to Co-2EH [ 24 , 25 ], and its congeners with increased solubility in organic solvents [ 26 , 27 ].…”