Abstract
High solid (HS) alkyd resins with low amount of volatile organic compounds (VOC) were developed as the result of new VOC solvent directive that limit the amount of VOC in decorative paints. Due to specific chemical structure of HS alkyd resins and possible deterioration of some applicative properties the optimal combination of driers is an important subject of research. In our present work we studied the influence of iron (Fe) and cobalt (Co) surface driers with strontium (Sr) through drier on the film formation of HS alkyd coatings. The kinetics of autoxidation was analysed using FT-IR spectroscopy. Further, applicative properties like drying time and film hardness were examined. In the end, electrochemical impedance spectroscopy (EIS) was used to evaluate the quality of cured HS alkyd coating films after exposure in the humidity chamber. It was established that the addition of the Sr drier to surface driers accelerates the film formation process. As higher amounts of the Sr drier were added, final drying times were reduced and film hardness increased. The highest quality of cured films were observed for Co/Sr and Fe/Sr drier combination at 1:1 concentration ratio.
Highlights
Alkyd coatings are complex mixtures based on alkyd polymers, which have both a decorative and a protective function
From the FT-IR spectra of High solid (HS) alkyd coating shown in Fig. 3 we can observe different band assignments that belong to chemical groups or bonds.[9]
HS alkyd resins have specific chemical structures that influence on physical and chemical changes of HS alkyd coatings during curing process; they can be optimised with the combination of surface and through driers
Summary
Alkyd coatings are complex mixtures based on alkyd polymers, which have both a decorative and a protective function. The formation of a film is a process where physical and chemical changes occur.[1,2] Chemical changes are the consequence of a free-radical reactions known as autoxidation. Through driers promote curing beneath the surface of the coating and improve the stability of the surface driers. They form oxygen-metal-oxygen crosslinks by reacting hydroxyl and carboxyl groups with polymer molecules, which contribute to the through-drying process.[4,5] Auxiliary driers inhibit phase separation from the coating surface.[4] To assure optimal film formation, coatings usually contain a mixture of all three types of driers.[5] The amount of driers needed is system specific and should be kept to the minimum possible level.[3,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
