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.
展开▼
