Titanium Dioxide Pigments and Manufacturing Method
AssigneeTronox LLC
InventorsVenkata Rama Rao Goparaju, Michael L. Ashley
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Abstract
The invention provides a coated inorganic oxide pigment. The inventive coated inorganic oxide pigment comprises an inorganic oxide base pigment, a porous inorganic coating formed on the base pigment, and a dense inorganic coating formed on the base pigment. The porous inorganic coating and dense inorganic coating each consist essentially of a material selected from the group consisting of silica and alumina. In another aspect, the invention provides a method of manufacturing a coated inorganic oxide pigment. In yet another aspect, the invention provides a polymer composition comprising a base polymer, and a coated inorganic oxide pigment admixed with the base polymer.
Claims63
A coated inorganic oxide pigment, comprising:
- an inorganic oxide base pigment;
- a porous inorganic coating formed on said base pigment, said porous inorganic coating consisting essentially of a material selected from the group consisting of alumina and silica;
- and
- a dense inorganic coating formed on said base pigment, said dense inorganic coating consisting essentially of a material selected from the group consisting of silica and alumina.
A coated inorganic oxide pigment, comprising:
- a titanium dioxide base pigment;
- a porous inorganic coating formed on said base pigment in situ in an aqueous slurry at a temperature in the range of from about 40° C. to about 90° C., wherein said porous inorganic coating consists essentially of a material selected from the group consisting of alumina and silica, wherein:
- if said porous inorganic coating consists essentially of alumina, it is formed on said base pigment at a pH in the range of from about 8 to about 11 and in an amount in the range of from about 2% to about 14% by weight, based on the weight of said base pigment;
- and
- if said porous inorganic coating consists essentially of silica, it is formed on said base pigment at a pH in the range of from about 3 to about 7 and in an amount in the range of from about 5% to about 14% by weight, based on the weight of said base pigment;
- and
- a dense inorganic coating formed on said base pigment in situ in an aqueous slurry at a temperature in the range of from about 40° C. to about 90° C., wherein said dense inorganic coating consists essentially of a material selected from the group consisting of silica and alumina, wherein:
- if said dense inorganic coating consists essentially of silica, it is formed on said base pigment at a pH in the range of from about 8 to about 11 and in an amount in the range of from about 5% to about 14% by weight, based on the weight of said base pigment;
- and
- if said dense inorganic coating consists essentially of alumina, it is formed on said base pigment at a pH in the range of from about 4 to about 7 and in an amount in the range of from about 2% to about 14% by weight, based on the weight of said base pigment.
A method of manufacturing a coated inorganic oxide pigment, comprising:
- a) forming an aqueous slurry comprising an inorganic oxide base pigment;
- b) forming at least one porous inorganic coating on said inorganic oxide base pigment particles in situ in said aqueous slurry, said porous inorganic coating consisting essentially of a material selected from the group consisting of alumina and silica;
- and
- c) forming at least one dense inorganic coating on said inorganic oxide base pigment particles in situ in said aqueous slurry, said dense inorganic coating consisting essentially of a material selected from the group consisting of alumina and silica.
A polymer composition, comprising:
- a base polymer;
- and
- a coated inorganic oxide pigment admixed with said base polymer, said coated inorganic oxide pigment including:
- an inorganic oxide base pigment;
- a porous inorganic coating formed on said base pigment, said porous inorganic coating consisting essentially of a material selected from the group consisting of alumina and silica;
- and
- a dense inorganic coating formed on said base pigment, said dense inorganic coating consisting essentially of a material selected from the group consisting of silica and alumina.
Dependencies are inferred from the claim text.