Use of polytetrafluoroethylene resin particles to reduce the abrasion of abrasive pigments

A slurry comprising water and solids consisting essentially of particles of fully calcined clay pigment having an average size in the range of 0.6 to 0.8 microns and from 0.01% to 0.2% based on the dry weight of said pigment, of substantially spherical colloidial nonfibrillated particles of a polytetrafluoroethylene resin, said amount of said polytetrafluoroethylene resin being effective to reduce the Einlehner abrasion of said pigment.

A process for decreasing the Einlehner abrasion of an abrasive pigment which is in the form of an aqueous slurry, said process comprising mixing said slurry at low shear and at ambient temperature with a colloidal aqueous dispersion of polytetrafluoroethylene resin particles without fibrillating said resin particles, the amount of said resin dispersion being effective to reduce the abrasion of said pigment.

A process for decreasing the Einlehner abrasion of a dry abrasive pigment which comprising applying at ambient room temperature a colloidal aqueous dispersion of polytetrafluoroethylene substantially spherical resin particles to a dry abrasive pigment at ambient temperature without fibrillating said resin particles, the amount of said resin dispersion being effective to reduce the abrasion of said pigment.

A process for decreasing the Einlehner abrasion of a fully calcined kaolin pigment having an average size in the range of 0.6 to 0.8 microns, which comprises mixing under low shear conditions and at ambient temperature from 0.01% to 0.5% weight percent based upon the dry weight of said pigment, of polytetrafluoroethylene resin particles contained in an aqueous dispersion, said resin particles being substantially spheroidal and having an average size in the range of 0.10 to 0.30 microns, and recovering the admixture without fibrillating said resin particles.