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US 8,557,037 B2Granted
Ultrafine hydrous kaolin pigments, methods of making the pigments, and methods of using the pigments in gloss paint formulations
AssigneeBASF SE
InventorsNavin Patel, Sharad Mathur, Ashok Khokhani, Kenneth W Folmar
Life of this patent
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Abstract
Disclosed are methods of processing kaolin to produce ultrafine hydrous kaolin. The methods involve processing gray crude kaolin by subjecting the kaolin crude to flotation and then centrifuging the kaolin to provide a fine stream that is subject to refinement. Also disclosed are systems for the automated processing of gray crude kaolin to produce the ultrafine hydrous kaolin and paint compositions that contain the ultrafine hydrous kaolin.
Claims24
A method of processing kaolin, comprising sequentially:
- subjecting a kaolin crude comprising at least 75 wt. % of gray kaolin to flotation to provide a kaolin having reduced titania content;
- centrifuging the kaolin having reduced titania content at high speeds to provide a coarse stream and a fine stream, the coarse stream comprising kaolin wherein at least about 70% by weight has a size of 2 microns or less, the fine stream comprising kaolin wherein at least about 80% by weight has a size of 1 micron or less;
- and
- refining the fine stream into an ultrafine hydrous kaolin pigment;
- said refining comprising flocculation, bleaching, filtering, spray drying, and pulverizing after spray drying,
- said ultrafine hydrous kaolin pigment comprising particles wherein at least about 97% by weight of the particles have a size of 2 microns or less, at least about 96% by weight of the particles have a size of 1 micron or less, at least about 89% by weight of the particles have a size of 0.5 microns or less, at least about 67% of the particles have a size of 0.3 microns or less, a surface area of the particles is more than 23 m2/g, and brightness of the particles is at least about 91;
- a moisture level less than about 1% by weight, from 0.29 to about 0.75% by weight of titania, and from 0.89 to about 1.5% by weight of iron oxide,
- said ultrafine hydrous kaolin pigment comprising no charged inorganic or organic molecules from selective flocculation, and
- wherein the method does not comprise selective flocculation.
6 more elements
A paint composition, comprising:
- a major amount of a paint vehicle;
- and
- a minor amount of ultrafine hydrous kaolin pigment prepared by a process comprising:
- subjecting a kaolin crude comprising at least 75 wt. % of gray kaolin to flotation to provide a kaolin having reduced titania content;
- centrifuging the kaolin having reduced titania content at high speeds to provide a coarse stream and a fine stream, the coarse stream comprising kaolin wherein at least about 70% by weight has a size of 2 microns or less, the fine stream comprising kaolin wherein at least about 80% by weight has a size of 1 micron or less, and
- refining the fine stream into an ultrafine hydrous kaolin pigment;
- said refining comprising flocculation, bleaching, filtering, spray drying, and pulverizing after said spray drying,
- said ultrafine hydrous kaolin pigment comprising particles wherein at least about 97% by weight of the particles have a size of 2 microns or less, at least about 96% by weight of the particles have a size of 1 micron or less, at least about 89% by weight of the particles have a size of 0.5 microns or less, at least about 67% of the particles have a size of 0.3 microns or less, a surface area of the particles is more than 23 m2/g, and brightness of the particles is at least about 91;
- a moisture level less than about 1% by weight, from 0.29 to about 0.75% by weight of titania, and from 0.89 to about 1.5% by weight of iron oxide,
- said ultrafine hydrous kaolin pigment comprising no charged inorganic or organic molecules from selective flocculation,
- said paint composition having a high gloss finish and a gloss at 20 degrees from 14.7 to 73.5, and
- wherein the process of preparing the ultrafine hydrous kaolin pigment does not comprise selective flocculation.
9 more elements
A paint composition, comprising:
- a major amount of a paint vehicle;
- and
- a minor amount of ultrafine hydrous kaolin pigment:
- said ultrafine hydrous kaolin pigment comprising particles wherein at least about 97% by weight of the particles have a size of 2 microns or less, at least about 96% by weight of the particles have a size of 1 micron or less, at least about 89% by weight of the particles have a size of 0.5 microns or less, at least about 67% of the particles have a size of 0.3 microns or less, a surface area of the particles is more than 23 m2/g, and brightness of the particles is at least about 91;
- a moisture level less than about 1% by weight, from 0.29 to about 0.75% by weight of titania, and from 0.89 to about 1.5% by weight of iron oxide,
- said paint composition having a high gloss finish and a gloss at 20 degrees from 14.7 to 73.5.
3 more elements
A paint composition, comprising:
- a major amount of a paint vehicle;
- and
- a minor amount of ultrafine hydrous kaolin pigment:
- said ultrafine hydrous kaolin pigment comprising particles wherein at least about 97% by weight of the particles have a size of 2 microns or less, at least about 96% by weight of the particles have a size of 1 micron or less, at least about 89% by weight of the particles have a size of 0.5 microns or less, at least about 67% of the particles have a size of 0.3 microns or less, a surface area of the particles is more than 23 m2/g, and brightness of the particles is at least about 91;
- a moisture level less than about 1% by weight, from 0.29 to about 0.75% by weight of titania, and from 0.89 to about 1.5% by weight of iron oxide,
- said ultrafine hydrous kaolin pigment comprising no charged inorganic or organic molecules from selective flocculation, and
- said paint composition having a high gloss finish and a gloss at 20 degrees from 14.7 to 73.5.
4 more elements
A paint composition, comprising:
- a major amount of a paint vehicle;
- and
- a minor amount of ultrafine hydrous kaolin pigment prepared by a process comprising:
- subjecting a kaolin crude comprising at least 75 wt. % of gray kaolin to flotation to provide a kaolin having reduced titania content;
- centrifuging the kaolin having reduced titania content at high speeds to provide a coarse stream and a fine stream, the coarse stream comprising kaolin wherein at least about 70% by weight has a size of 2 microns or less, the fine stream comprising kaolin wherein at least about 80% by weight has a size of 1 micron or less, and
- refining the fine stream into an ultrafine hydrous kaolin pigment;
- said refining comprising flocculation, bleaching, filtering, spray drying, and pulverizing after said spray drying,
- said ultrafine hydrous kaolin pigment comprising particles wherein at least about 97% by weight of the particles have a size of 2 microns or less, at least about 96% by weight of the particles have a size of 1 micron or less, at least about 89% by weight of the particles have a size of 0.5 microns or less, at least about 67% of the particles have a size of 0.3 microns or less, a surface area of the particles is more than 23 m2/g, and brightness of the particles is at least about 91;
- a moisture level less than about 1% by weight, from 0.29 to about 0.75% by weight of titania, and from 0.89 to about 1.5% by weight of iron oxide,
- said paint composition having a high gloss finish and a gloss at 20 degrees from 14.7 to 73.5, and
- wherein the process of preparing the ultrafine hydrous kaolin pigment does not comprise selective flocculation.
8 more elements
A paint composition, comprising:
- a major amount of a paint vehicle;
- and
- a minor amount of ultrafine hydrous kaolin pigment:
- said ultrafine hydrous kaolin pigment comprising particles wherein at least about 97% by weight of the particles have a size of 2 microns or less, at least about 96% by weight of the particles have a size of 1 micron or less, at least about 89% by weight of the particles have a size of 0.5 microns or less, at least about 67% of the particles have a size of 0.3 microns or less, a surface area of the particles is more than 23 m2/g, and brightness of the particles is at least about 91;
- a moisture level less than about 1% by weight, from 0.29 to about 0.75% by weight of titania, and from 0.89 to about 1.5% by weight of iron oxide.
2 more elements
Dependencies are inferred from the claim text.