Acid and scratch resistant coatings for melamine based OEM applications

Increasing the mar resistance of OEM clear coats has been one of the main R&D priorities of paint manufacturers over the last years. Reaching a good mar resistance level without compromising other coating properties such as acid resistance proves to be a major challenge. We investigated the use of branched glycidyl esters in melamine based OEM acrylic formulations. Our results show that systems based on this type of esters lead to good overall coating properties as well as a good balance between acid and scratch resistance.     

Proton-Induced Spin State Switching in an FeIII Complex

Reversible proton-induced spin state switching of an Fe^III complex in solution is observed at room temperature. A reversible magnetic response was detected in the complex, [Fe^III(sal₂323)]ClO₄ ( 1 ), using Evans’ method ¹H NMR spectroscopy which indicated cumulative switching from low-spin to high-spin upon addition of one and two equivalents of acid. Infrared spectroscopy suggests a coordination-induced spin state switching (CISSS) effect, whereby protonation displaces the metal-phenoxo donors. The analogous complex, [Fe^III(4-NEt₂-sal₂323)]ClO₄ ( 2 ), with a diethylamino group on the ligand, was used to combine the magnetic change with a colorimetric response. Comparison of the protonation responses of 1 and 2 reveals that the magnetic switching is caused by perturbation of the immediate coordination sphere of the complex. These complexes constitute a new class of analyte sensor which operate by magneto-modulation, and in the case of 2 , also yield a colorimetric response.