Method for improving rheological properties of an aqueous pigment slurry and a dispersion agent

A method for improving the rheological high shear properties of an aqueous pigment slurry comprising calcium carbonate, kaolin, calcinated kaolin, talc, titanium dioxide, gypsum, chalk, satine white, barium sulphate, sodium aluminium silicate, aluminium hydroxide or any of their mixture, the aqueous pigment slurry having a solids content of about 68%, the method comprising adding a dispersion agent to an aqueous phase of a slurry comprising pigment particles or to the aqueous phase into which the pigment particles are to be added, the dispersion agent comprising styrene acrylate copolymer, wherein the styrene acrylate copolymer comprises starch, wherein the dispersion agent improves the rheological properties of the slurry, and wherein the dispersion agent decreases the high shear viscosity of the slurry, and further comprising adding also a conventional dispersion agent comprising straight-chain polyacrylate to the aqueous phase.