High solids latexes for paper coatings

Claim 1

An improved hight solids formulation for coating paper which comprises an aqueous medium having dispersed therein a functionally effective amount of a finely divided mineral filler and a high solids synthetic bimodal latex comprising two separate and distinct particles size distributions and comprising in polymerized form open chain conjugated diene and alkenyl mononuclear aromatic monomers; wherein each of said distributions comprises particles which are substantially uniform in diameter such that said latex, when mixed with said filler in said aqueous medium, provides a coating formulation which approaches a viscosity which is no longer manageable at a higher solids content than that solids content exhibited by a formulation comprising an aqueous medium, a filler and a monodisperse or highly multi-disperse latex; whereby the small latex particles of said distribution of the bimodal latex provide the capability to provide an increase in the solids content and a decrease in viscosity at high shear of the formulation over that of a formulation comprising a monodisperse latex of a particle size similar to that of the large latex particle distribution of the bimodal latex; and whereby the large latex particles of said distribution of the bimodal latex provide the capability to increase the solids contend of the formulation at low shear over that of a formulation comprising a monodisperse latex of a particle size similar to that of the small latex particle distribution of the bimodal latex.