Surface-treated pigments
a surface treatment and pigment technology, applied in the field of inorganic pigments, can solve the problems of inherently dusty titanium dioxide powders, often exhibit poor powder flow characteristics, and powders usually exhibit reduced opacifying properties, so as to improve dispersion, improve physical and chemical qualities, and reduce chemical reactivity
Examples
example 1
[0062] Particulate titanium dioxide pigment intermediate obtained from the vapor phase oxidation of titanium tetrachloride and containing 0.8% alumina in its crystalline lattice, was dispersed in water in the presence of 0.18% by weight (based on the pigment) of sodium hexametaphosphate dispersant and with sodium hydroxide sufficient to adjust the pH of the dispersion to a minimum value of 9.5, to provide an aqueous dispersion having a solids content of 35% by weight. The resulting titanium dioxide slurry was sand milled, using a zircon sand-to-pigment weight ratio of 4 to 1, until a volume average particle size was achieved wherein >90% of the particles were smaller than 0.63 microns, as determined utilizing a Microtrac X1 00 Particle Size Analyzer (Microtrac Inc. Montgomeryville, Pa.). The slurry was heated to 60° C., acidified to a pH of 2.0 using concentrated sulfuric acid, then allowed to digest at 60° C. for 30 minutes. After this, adjustment of the pigment slurry pH to a valu...
example 2
[0071] Particulate titanium dioxide pigment intermediate obtained from the vapor phase oxidation of titanium tetrachloride and containing 0.8% alumina in its crystalline lattice was dispersed in water in the presence of 0.18% by weight (based on pigment) of sodium hexametaphosphate dispersant, along with sufficient sodium hydroxide to adjust the pH of the dispersion to a minimum value of 9.5, to yield an aqueous dispersion with a solids content of 35% by weight. The resulting titanium dioxide slurry was sand milled, using a zircon sand-to-pigment weight ratio of 4 to 1, until a volume average particle size was achieved wherein >90% of the particles were smaller than 0.63 microns, as determined utilizing a Microtrac X100 Particle Size Analyzer. The slurry was heated to 60° C., acidified to a pH of 2.0 using concentrated sulfuric acid, then allowed to digest at 60° C. for 30 minutes. The pigment slurry pH was adjusted then to a value of 6.2 using 20% by weight aqueous sodium hydroxide...
example 3
[0080] Particulate titanium dioxide pigment intermediate obtained from the vapor phase oxidation of titanium tetrachloride and containing 0.8% alumina in its crystalline lattice was dispersed in water in the presence of 0.18% by weight (based on pigment) of sodium hexametaphosphate dispersant, along with sufficient sodium hydroxide to adjust the pH of the dispersion to a minimum value of 9.5, to yield an aqueous dispersion with a solids content of 35% by weight. The resulting titanium dioxide slurry was sand milled, using a zircon sand-to-pigment weight ratio of 4 to 1, until a volume average particle size was achieved wherein >90% of the particles were smaller than 0.63 microns, as determined utilizing a Microtrac X100 Particle Size Analyzer. The slurry was heated to 60° C., acidified to a pH of 2.0 using concentrated sulfuric acid, then treated with 1% alumina, added as a 357 g / liter aqueous sodium aluminate solution. During the addition of the sodium aluminate solution, the pH of...
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Abstract
Description
Claims
Application Information
- IPC
- C04B14/20
- CPC
- C09C3/06; C09C1/3653; C01P2006/64
- Inventors
- CRAIG, DANIEL H.