Use of 2,3-dihydroxynaphthalene-6-sulfonic acid salts as dispersants in coating compositions

Stable dispersions of nanoparticles and microparticles in liquids and method for their preparation are disclosed. The disclosure particularly relates to a dispersion composition comprising: (a) about 0.1 wt% to about 25 wt%, based on the total weight of the dispersion, of a dispersant the formula (I), in which R is a cation selected from the group consisting of Na+, Li+, K+ and NR'4+, in which each R' is independently -H, -CH3, -CH2-CH3 or -CH2-CH2-OH; (b) about 1 wt% to about 90 wt%, based on the total weight of the dispersion, of particles selected from the group consisting of metal oxide particles, particles having a metal oxide surface, metal particles and mixtures thereof, in which the particles have a particle size of about 1 nm to about 2000 nm; and (c) about 10 wt% to about 90 wt%, based on the total weight of the dispersion, of a liquid selected from the group consisting of water, ethylene glycol, propylene glycol, glycerin, glycol mono-ethers of the formula R"OCH2CH2OH, in which R" is an alkyl group of one to four carbon atoms, and mixtures thereof; in which the particles are dispersed in the polar liquid. A method for forming a stable dispersion of said nanoparticles in a liquid is also disclosed. These dispersion compositions are suitable as master batches in the preparation of inks, coatings, and adhesives with enhanced mechanical, chemical, electrical, optical or magnetic properties.