Patent ID: 7138160

Claim:
A method comprising coating paper or cardboard with a coating color, wherein the coating color comprises an agent for simultaneously adjusting the water retention of the coating color and its Brookfield viscosity, and wherein the agent comprises a copolymer that is water soluble in a neutral or alkaline medium, which copolymer comprises: A) 25% to 45% by weight monomer units selected from the group consisting of styrene, α-methylstyrene, and mixtures thereof, B) 30% to 65% by weight anionic monomer units, C) an amount of 10% to 30% by weight non-ionic monomer units other than the monomers A), selected from the group consisting of oxyalkylated monomers with ethylenic non-saturation terminated by linear or branched alkyl, aryl, alkylaryl or arylalkyl groups having 1 to 50 carbon atoms, D) 0% to 5% by weight cross-linking monomer units.