Zirconium propionate is a white powder with molecular formula Zr(CH 3 CH 2 COO) 4 . Its structure is complex, but is believed to be based on hydroxy -bridged zirconium polymers , with the propionate carboxyl group bonded to the zirconium. Propionates are salts or esters of propionic acid . It is not soluble in water, but dissolves in a solution of isopropanol , ethanol and ethyl acetate . When tamped or untamped, it has a density of g/cm 3 or g/cm 3 respectively. It is used to promote adhesion in solvent -based inks . Impurities of Hafnium are commonly present.
The peel adhesion of nitrocellulose to low density polyethylene, which had been treated in chromic-sulfuric acid or by corona discharge, is much increased when zirconium propionate is added to the nitrocellulose solution. Contact angle measurements on nitrocellulose and polyethylene surfaces treated with zirconium propionate show that their surface energies are not altered. The viscosities of solutions of nitrocellulose in an ethyl acetate/ethanol mixture are increased by zirconium propionate. The interpretation is that zirconium propionate interacts with carboxylic groups on polyethylene and hydrogen bonds to nitrocellulose.