초록 ▼

A composite particulate pigmentary material is disclosed which comprises an association of at least two chemically distinct materials in which the particles of one material carry a positive surface charge and the particles of the second material carry a negative surface charge and particles are held

A composite particulate pigmentary material is disclosed which comprises an association of at least two chemically distinct materials in which the particles of one material carry a positive surface charge and the particles of the second material carry a negative surface charge and particles are held in association as a result of these surface charges. Also disclosed is a method for preparing composite particulate pigmentary material comprising forming aqueous dispersions of two particulate materials under conditions in which the surface charges of the particles of the two materials are of different signs and mixing the dispersions. Typical materials useful for preparing the composite include inorganic pigments, fillers and extenders and organic polymeric microspheres. The product is useful as a pigment in, for example, paints, inks, paper and plastics.

대표청구항 ▼

A process for producing a composite particulate pigmentary material comprising forming an aqueous dispersion of particles of a first particulate material and an aqueous dispersion of particles of a second, chemically distinct, particulate material, the pH values of the dispersions so formed being su

A process for producing a composite particulate pigmentary material comprising forming an aqueous dispersion of particles of a first particulate material and an aqueous dispersion of particles of a second, chemically distinct, particulate material, the pH values of the dispersions so formed being such that the particles of both particulate materials carry a surface charge, the surface charge on the first particulate material being of opposite sign to the surface charge on the second particulate material and at least one of said dispersions being formed in the substantial absence of a dispersing agent and mixing said dispersions under conditions such that the mixing does not produce a reversal of the sign of the surface charge on one of the materials to produce an aqueous dispersion of composite particles, said composite particles comprising an association of particles of said first material and said second material, the particles of said first material being held in association with the particles of said second material as a result of said surface charges and wherein said aqueous dispersion of composite particles contains at least 35 percent by weight of said composite particles, said first material being an inorganic pigment or extender.