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

Active Publication Date: 2006-03-02
TRONOX LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0052] U.S. Pat. No. 6,713,543 describes a unique treatment for pigments which uses certain organo-phosphoric acids and / or their salts, resulting in improved physical and chemical qualities, including lacing resistance, improved dispersion and decreased chemical reactivity when these treated pigments are incorporated into polymeric matrices.

Problems solved by technology

However, titanium dioxide powders are inherently dusty and frequently exhibit poor powder flow characteristics during the handling of the powder itself, especially during formulation, compounding, and manufacture of end-use products.
While free-flowing powders with low dust properties can be obtained through known manufacturing practices, these powders usually exhibit reduced opacifying properties.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

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

Inorganic pigments, having deposited on the pigment surface at least one alkenyl- or alkyl-substituted succinic anhydride and at least one organic polyol, possess improved processibility and dispersibility in thermoplastic materials, and impart improved properties to thermoplastic compositions containing said surface-treated pigments.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. Ser. No. 10 / 928,389, filed Aug. 30, 2004.FIELD OF THE INVENTION [0002] This invention relates to inorganic pigments with improved surface treatments. The pigments of this invention are useful as opacifiers and colorants in the manufacture of products produced in many industries, including in coatings and coated goods, in plastics and articles made therefrom, and in paper and paper goods. BACKGROUND OF THE INVENTION [0003] Inorganic pigments are used as opacifiers and colorants in many industries including the coatings, plastics, and paper industries. In general, the effectiveness of the pigment in such applications depends on how evenly the pigment can be dispersed in a coating, in plastic or in paper. For this reason, pigments are generally handled in the form of a finely divided powder. For example, titanium dioxide, the most widely used white pigment in commerce today due to its abil...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C04B14/20
CPCC09C3/06C09C1/3653C01P2006/64
Inventor CRAIG, DANIEL H.
Owner TRONOX LLC
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