# US 7,611,575 B2 · High solids, large particle, calcined kaolin slurries

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- Number: US 7,611,575 B2
- Document ID: US7611575B2
- Status: Granted
- Kind: B2
- Application number: 10/518,792
- Filed: 2003-12-01
- Published: 2006-08-03
- Granted: 2009-11-03
- Earliest claimed: 2003-12-01
- Assignees: Imerys Pigments, Inc.
- Inventors: Edward J. Sare; Tommy L. Adkins; Stephen C. Raper
- Web page: https://patentgrep.com/patent/US7611575B2

## CPC

- D21H 19/40: siliceous, e.g. clays
- C09C 1/42: Clays
- C09D 5/027: {Dispersing agents (anti-settling agents C09D7/45)}
- C09D 5/028: {Pigments; Filters}
- C09D 5/14: Paints containing biocides, e.g. fungicides, insecticides or pesticides (C09D5/16 takes precedence)
- C09D 7/43: Thickening agents
- C09D 7/61: inorganic
- C09D 7/69: {Particle size larger than 1000 nm}
- C01P 2004/51: Particles with a specific particle size distribution
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2006/22: Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
- C01P 2006/60: Optical properties, e.g. expressed in CIELAB-values
- C01P 2006/62: L* (lightness axis)
- C01P 2006/63: a* (red-green axis)
- C01P 2006/64: b* (yellow-blue axis)
- C08K 3/346: {Clay}
- D21H 21/52: Additives of definite length or shape
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS}
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

The present invention relates to coarse calcined kaolin slurries having a high solids content. The invention also relates to methods of making such slurries. The resulting slurries can have a solids content of at least about 58% by weight wherein at least about 40% by weight of the calcined kaolin particles has a particle size of at least about 1 μm. The slurries can be stabilized where the solids show little settling from suspension. The slurries have many uses, including fillers or extenders in paint and coating compositions for paper or paper board. More generally, the inventive products may be used wherever calcined kaolins are used. The present invention also related to coarse calcined kaolin slurries having a multimodal particle size distribution and a high solids content.

## Claims

### Claim 1

A composition comprising a slurry comprising calcined kaolin, wherein at least about 40% by weight of the calcined kaolin has a particle size of at least about 1 μm, at least about 40% by weight of the calcined kaolin has a particle size of at least about 2 μm, the slurry has a solids content of at least about 58% by weight, relative to the total weight of the slurry, and the calcined kaolin has not been subjected to mechanical grinding.

### Claim 2 (depends on 1)

The composition according to claim 1, wherein at least about 40% by weight of the calcined kaolin has a particle size ranging from about 1 μm to about 10 μm.

### Claim 3 (depends on 1)

The composition according to claim 1, wherein at least about 45% by weight of the calcined kaolin has a particle size of at least about 1 μm.

### Claim 4 (depends on 1)

The composition according to claim 1, wherein at least about 50% by weight of the calcined kaolin has a particle size of at least about 1 μm.

### Claim 5 (depends on 1)

The composition according to claim 1, wherein the slurry has a solids content of at least about 60% by weight, relative to the total weight of the slurry.

### Claim 6 (depends on 1)

The composition according to claim 1, wherein the slurry further comprises at least one thickener.

### Claim 7 (depends on 6)

The composition according to claim 6, wherein the at least one thickener is chosen from cellulosic thickeners, montmorillonite, smectite clays, hydrophobically modified ethoxylated urethanes, polyacrylates, polyvinyl pyrrolidone, sodium alginate, xanthan gum, silica thickeners, sodium magnesium silicate, acrylic acid copolymers, and nonionic hydrophobically modified polyethers.

### Claim 8 (depends on 7)

The composition according to claim 7, wherein the at least one thickener is a cellulosic thickener chosen from alkyl celluloses, carboxymethyl celluloses, ethylhydroxyethyl celluloses, hydroxymethyl celluloses, hydroxyethyl celluloses, and hydroxypropyl celluloses.

### Claim 9 (depends on 6)

The composition according to claim 6, wherein the at least one thickener is present in an amount effective to stabilize the slurry.

### Claim 10 (depends on 9)

The composition according to claim 9, wherein the at least one thickener is present in an amount ranging from about 0.01% to about 4% by weight, relative to the total weight of the slurry.

### Claim 11 (depends on 10)

The composition according to claim 10, wherein the at least one thickener is present in an amount ranging from about 0.01% to about 2% by weight, relative to the total weight of the slurry.

### Claim 12 (depends on 1)

The composition according to claim 1, wherein the slurry further comprises at least one dispersant.

### Claim 13 (depends on 12)

The composition according to claim 12, wherein the at least one dispersant is present in an amount ranging from about 0.01% to about 2% by weight, relative to the total weight of the slurry.

### Claim 14 (depends on 13)

The composition according to claim 13, wherein the at least one dispersant is present in an amount ranging from about 0.01% to about 1% by weight, relative to the total weight of the slurry.

### Claim 15 (depends on 12)

The composition according to claim 12, wherein the at least one dispersant is chosen from polyelectrolytes, sodium salts of weak acids, potassium salts of weak acids, and water-soluble organic polymeric salts.

### Claim 16 (depends on 15)

The composition according to claim 15, wherein the at least one dispersant is a polyelectrolyte chosen from polyacrylates and copolymers containing polyacrylates.

### Claim 17 (depends on 12)

The composition according to claim 12, wherein the at least one dispersant is chosen from 2-amino-2-methyl-1-propanol, polyacrylates, sodium hexametaphosphates, polyphosphoric acid, condensed sodium phosphate, alkanolamines, tetrasodium pyrophosphate, trisodium phosphate, sodium hexametaphosphate, tetrasodium phosphate, sodium tripolyphosphate, sodium silicate, sodium carbonate, sodium salts of naphthalene sulfonic acid, potassium salts of naphthalene sulfonic acid, sodium salts of polymeric carboxylic acid, potassium salts of polymeric carboxylic acid, and polymethacrylates.

### Claim 18 (depends on 1)

The composition according to claim 1, wherein the slurry further comprises at least one biocide.

### Claim 19 (depends on 18)

The composition according to claim 18, wherein the at least one biocide is present in an amount ranging from about 0.01% to about 1% by weight, relative to the total weight of the slurry.

### Claim 20 (depends on 18)

The composition according to claim 18, wherein the at least one biocide is chosen from quaternary ammonium compounds, organosulphur compounds, and halogen-containing compounds.

### Claim 21 (depends on 18)

The composition according to claim 18, wherein the at least one biocide is chosen from metaborate, sodium dodecylbenzene sulphonate, sodium benzoate, benzisothiazolin, isothiazolin, thione, glutaraldehyde, bromonitropropanediol, bromohydroxyacetophenone, dibromodicyanobutane, sodium orthophenylphenate, dodecylguanidine hydrochloride, oxazolidines, adamantanes, hydantoins, dibromonitrilopropionamide, bromonitrostyrene, methylenebisthiocyanate, tetrakis hydroxymethyl phosphonium sulfate, sodium dimethyldithiocarbamate, and chloromethylphenol.

### Claim 22 (depends on 1)

The composition according to claim 1, wherein the slurry has a pH ranging from about 8 to about 10.

### Claim 23 (depends on 1)

The composition according to claim 1, wherein the slurry further comprises at least one pH modifier.

### Claim 24 (depends on 23)

The composition according to claim 23, wherein the at least one pH modifier is chosen from sodium carbonate, amino-2-methyl-1-propanol, sodium hydroxide and ammonium hydroxide.

### Claim 25 (depends on 1)

The composition according to claim 1, wherein the calcined kaolin comprises mullite.

### Claim 26

A method of preparing a slurry comprising: (a) providing a calcined kaolin, wherein at least about 40% by weight of the calcined kaolin has a particle size of at least about 1 μm, at least about 40% by weight of the calcined kaolin has a particle size of at least about 2 μm, and the calcined kaolin has not been subjected to mechanical grinding; (b) combining the calcined kaolin with water; and (c) obtaining a slurry having a solids content of at least about 58% by weight, relative to the total weight of the slurry.

### Claim 27 (depends on 26)

The method according to claim 26, further comprising introducing at least one dispersant prior to (c).

### Claim 28 (depends on 26)

The method according to claim 26, further comprising introducing at least one thickener prior to (c).

### Claim 29 (depends on 28)

The method according to claim 28, wherein the thickener is introduced in an amount effective to stabilize the slurry.

### Claim 30 (depends on 26)

The method according to claim 26, further comprising introducing at least one pH modifier prior to (c).

### Claim 31

A method of preparing a slurry having a solids content of at least about 58% by weight, relative to the weight of the slurry, said method comprising: providing a calcined kaolin, wherein at least about 40% by weight of the calcined kaolin has a particle size of at least about 1 μm, at least about 40% by weight of the calcined kaolin has a particle size of at least about 2 μm, and the calcined kaolin has not been subjected to mechanical grinding; and introducing the calcined kaolin to water.

### Claim 32

A paint comprising a slurry comprising calcined kaolin, wherein at least about 40% by weight of the calcined kaolin has a particle size of at least about 1 μm, at least about 40% by weight of the calcined kaolin has a particle size of at least about 2 μm, the slurry has a solids content of at least about 58% by weight, relative to the total weight of the slurry, and the calcined kaolin has not been subjected to mechanical grinding.

### Claim 33

A method of making a coated paper or coated paper board comprising: coating a fibrous substrate with slurry, the slurry comprising calcined kaolin wherein at least about 40% by weight of the calcined kaolin has a particle size of at least about 1 μm, at least about 40% by weight of the calcined kaolin has a particle size of at least about 2 μm, the slurry has a solids content of at least about 58% by weight, relative to the total weight of the slurry, and the calcined kaolin has not been subjected to mechanical grinding.