Researchers found that combining manganese-based desiccants with nitrogen and oxygen ligands significantly reduces the drying time of tung oil.

Although manganese-based driers with nitrogen- or oxygen-containing ligands can accelerate the surface drying of tung oil film, their mechanical property performance does not meet industrial requirements. To address this, the drying activities of manganese-based driers with nitrogen- and oxygen-containing ligands on tung oil film were investigated. The curing process of tung oil film catalyzed by the combination driers of Mn(OH)₂(benz)₂·Mn(H₂O)₂(acac)₂, MnCl₂(bipy)₂·Mn(H₂O)₂(acac)₂, and MnCl₂(bipy)₂·Mn(OH)₂(benz)₂ was revealed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA).

The results revealed that the combination driers enhanced the drying activities of Mn²⁺ in tung oil due to a synergistic effect between Mn²⁺ and its ligands. This process catalyzed the crosslinking of tung oil, giving the tung oil film a faster drying time, greater scratch resistance, increased hardness, improved flexibility, and greater thermal stability. These materials may replace traditional heavy metal driers to produce tung oil films with outstanding mechanical properties. Additionally, this paper describes the drying mechanism of these manganese-based driers with a combination of nitrogen-containing and oxygen-containing ligands and provides a new tung oil drying method.

Source: Progress in Organic Coatings Volume 197, December 2024, 108792