BAC - Ethylene Glycol Monobutyl Ether Acetate

About This Product

Ethylene glycol monobutyl ether acetate, known as BAC or butyl glycol acetate, has the formula C8H16O3 and CAS number 112-07-2. It is produced by acetylating ethylene glycol monobutyl ether, and is supplied as a clear colourless liquid with a mild ester odour. Esterifying the hydroxyl group changes the solvent in three linked ways. It removes the active hydrogen, which is decisive in polyurethane work: a free hydroxyl reacts with isocyanate, so an unmodified glycol ether cannot be used in a two-pack PU system, while the acetate can. It removes the molecule's ability to hydrogen-bond with water, so water miscibility drops sharply and the solvent becomes essentially oil-soluble. And it raises the boiling point and slows evaporation substantially, which makes it a tail solvent, staying in the film after the faster components have gone and giving the resin time to flow out into a smooth surface. That combination of slow release and strong resin solvency is why it is specified in high-gloss and automotive finishes. It is used in automotive and industrial coatings, two-pack polyurethane systems, printing inks, coil coatings and as a retarder and flow aid. Bio Green Chem supplies BAC to specification on assay, free glycol ether, acidity, water content, colour and residue.