Chelating compounds as potential flash rust inhibitors and melamine & aziridine cure of acrylic colloidal unimolecular polymers (CUPs)

Waterborne coatings on ferrous substrates usually show flash rusting which decreases the adhesion of the coating and the corrosion products can form a stain. Chelating compounds were investigated as potential flash rust inhibitors. Compounds being evaluated include amine alcohols, diamines and sulfur containing amines. A new corrosion inhibitor 2,5-bis(thioaceticacid)-1,3,4-thiadiazole (H2ADTZ) was synthesized and its performance characteristics were evaluated. It was noted that the observed structure of 1,3,4-thiadiazolidine-2,5-dithione (also known as 2,5-dimercapto-1,3,4-thiadiazole (DMTD or DMcT)) has been previously reported in three different tautomeric forms including -dithiol and -dithione. The relative stability of each form as well as the synthesis and characterization of the structures of mono- and dialkylated forms of 5-mercapto-1,3,4-thiadiazole-2(3H)-thione (MTT) were examined. The methods of X-ray crystallography, NMR spectroscopy and ab-initio electronic structure calculations were combined to understand the reactivity and structure of each compound. Polymers were synthesized with a 1:7 or 1:8 ratio of acrylic acid to acrylate monomers to produce an acid rich resin. The polymers were reduced and solvent stripped to produce Colloidal Unimolecular Polymers (CUPs). These particles are typically 3-9 nanometers in diameter depending upon the molecular weight. They were then formulated into a clear coating with either a melamine (bake) or an aziridine (ambient cure) and then cured. The melamine system was solvent free, a near zero VOC and the aziridine system was very low to near zero VOC. The coatings were evaluated for their MEK resistance, adhesion, hardness, gloss, flexibility, wet adhesion, abrasion and impact resistance properties

Aziridine Cure of Acrylic Colloidal Unimolecular Polymers (CUPs)

Polymers were synthesized with a 1:7 or 1:8 ratio of acrylic acid to acrylate monomers to produce an acid-rich resin. The polymers were water-reduced and solvent-stripped to produce colloidal unimolecular polymers (CUPs). These particles are typically 3-9 nm in diameter, depending upon the molecular weight, and have different rheological behavior from micelles, polyelectrolytes, fullerenes, and latex particles, due to their charged surface and large surface areas. They were then formulated into ambient cure clearcoatings with aziridine crosslinking. These aziridine-cured acrylic CUPs were either solvent-free or very low VOC. The coatings were evaluated for their MEK resistance, adhesion, hardness, gloss, flexibility, wet adhesion, and abrasion and impact resistance properties. © 2013 American Coatings Association & Oil and Colour Chemists\u27 Association

Ironing Out Stains

Flash rusting of waterborne coatings can result in staining and reduced adhesion. Common inhibitors may leach out of applied coatings, sometimes causing blistering. Compounds which prevent oxidation by forming a tight chelated complex with the metal substrate are shown to offer potential as flash rust inhibitors

5-Mercapto-1,3,4-thiadiazole-2(3H)-thione: Synthesis and Structure of Alkylated Derivatives

The observed structure of 1,3,4-thiadiazolidine-2,5-dithione (also known as 2,5-dimercapto-1,3,4-thiadiazole) has been previously reported in three different tautomeric forms including - dithiol and - dithione. This report examines the relative stability of each form and also reports synthesis and characterization of the structures of mono-alkylated and di-alkylated forms of 5-mercapto-1,3,4-thiadiazole-2(3H)-thione. The methods of X-ray crystallography, NMR spectroscopy, and ab initio electronic structure calculations were combined to understand the reactivity and structure of each compound