Catalytic effects of transition metals in the form of the salts of organic acids in the cross linking of alkyds.

Purpose - To study the drying effects of cobalt, manganous and mixed salts for their catalytic action in cross linking reactions occurring during the creation of an alkyd resin film. Design/methodology/approach - The driers of Co-octoate, Mn-octoate, Mn-octoate with an active organic ligand, and mixed drier containing the salts of Mn, Ca, and Zn were employed in the cross linking reactions of alkyls. The study verified the possibility of using manganese as an active cation in catalytic curing reactions. The course of the cross-linking of alkyds was monitored on a model system of the reactions of drier with ethyl linoleate, using FTIR spectroscopy. Reaction-rate constants corresponding to the first phase of cross linking were obtained. The driers under scrutiny were used to identify the time of the drying of alkyd resin modified with flax oil. The final phase of the cross linking reactions was monitored by means of measurement the hardness of the created alkyd film depending on time. Findings - The driers under scrutiny were found to have catalytic effects in auto-oxidation reactions. Very high efficiency was found with all of the driers. The highest efficiency was found with Co-octoate resulting in the development of the highest hardness of coatings. Mn-octoate and mixed driers show a steeper increase in film hardness than Co-drier, yet the final films are suppler. Practical implications - The driers studied can be conveniently used to accelerate creation of alkyd coatings modified with natural oils and designed for both industrial and decorative purposes. Originality/value - The method of identifying the kinetic parameters of the cross-linking reactions of alkyds is relatively new and facilitates the localisation of driers that are optimum for specific paints formulations. Of benefit is also the study of Mn-driers that are more environmentally acceptable than Co-driers. [ABSTRACT FROM AUTHOR]