Patent ID: 8252143

Claim:
A filler consisting essentially of modified clay and cellulose derivative being an anionic carboxyalkyl cellulose having a degree of substitution of net ionic groups from about 0.15 up to about 0.40, a degree of substitution of carboxyalkyl groups from about 0.10 up to 0.40, and a degree of substitution of cationic quaternary ammonium groups from about 0.05 up to about 0.50, the cationic quaternary ammonium groups being obtained by reacting cellulose or derivatives thereof with a quaternization agent selected from 2, 3 epoxypropyl trimethyl ammonium chloride, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and mixtures thereof, wherein the clay has been modified by said cellulose derivative, and the filler has a cellulose derivative content of at least 0.01% by weight.