pigment preparation process
Patent No. U.S. 6,569,231 B1
Degussa has received a patent for a pigment preparation comprising at least one member selected from the group consisting of pigments and carbon blacks and at least one member selected from the group consisting of polymers and surfactants. The surfactants are selected from a group consisting of cross-linked polyoxyethylene acrylic acids, fatty alcohol polyglycol ethers, polyvinylpyrrolidone, alkyl ethoxylates, alcohol alkoxylates, alkylpheno polyglycol ethers, lignin sulfonates, naphthalene sulfonic acid derivatives and mixtures thereof. The pigment preparation is prepared from an aqueous dispersion by freeze-drying.