Composite of inorganic and/or organic microparticles and nano-dolomite particles

Patent metadata

Field	Value
Publication number	US-9944798-B2
Application number	US-22703107-A
Country	US
Kind code	B2
Filing date	Jun 5, 2007
Priority date	Jun 9, 2006
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The present invention relates to composites, comprising inorganic and/or organic pigments and/or fillers in the form of microparticles, the surface of which is coated at least partially with finely divided nano-dolomite with the help of binders based on copolymers comprising as monomers one or more dicarboxylic acids and one or more monomers from the group of diamines, triamines, dialkanolamines or trialkanolamines, a method for producing such composites, aqueous slurries thereof, their use, and the use of the inventive binders for coating the microparticles with nano-dolomite.

First claim

The invention claimed is:

1. A composite comprising:
(i) 20 to 80 wt. %, based on the total dry weight of the composite, of microparticles having a spherical equivalent diameter of 0.3 μm to 12 μm, wherein the microparticles are organic microparticles comprising polyethylene, polypropylene, polyethylene terephthalate, polystyrene or any mixture thereof, and wherein the microparticles have a spherical structure, a hollow spherical structure, or a hollow hemispherical structure;
(ii) 80 to 20 wt. %, based on the total dry weight of the composite, of a dolomite nanoparticle composition at least partially coating the microparticles, wherein ≥90% of particles of the dolomite nanoparticle composition, based on the number N of particles, have a spherical equivalent diameter of 20 nm to 200 nm, wherein the dolomite nanoparticle composition is ground natural dolomite that is ground in the presence of one or more grinding aids and/or dispersants, and wherein the dolomite nanoparticle composition contains more than 90% dolomite and one or more grinding aids and/or dispersants;
(iii) 0.3 to 3 wt. %, based on the total dry weight of the composite, of a binder that facilitates adhesion of the microparticles with the dolomite nanoparticle composition, wherein the binder is a copolymer comprising one or more dicarboxylic acids, and one or more diamines, triamines, dialkanolamines or trialkanolamines, and
(iv) optionally one or more additional dispersants,
wherein the sum of the weight amounts of the microparticles, the dolomite nanoparticle composition, the binder, and grinding aids and/or dispersants is 100% of the composite.

2. The composite according to claim 1 , wherein the microparticles have an essentially spherical structure.

3. The composite according to claim 1 , wherein the microparticles have a hollow spherical or hollow hemispherical structure.

4. The composite according to claim 1 , wherein the spherical equivalent diameter of the organic microparticles is 0.9 μm to 1.1 μm.

5. The composite according to claim 1 , wherein the spherical equivalent diameter of the organic microparticles is 0.7 μm to 1.4 μm.

6. The composite according to claim 1 , wherein the spherical equivalent diameter of the organic microparticles is 0.4 μm to 1.5 μm.

7. The composite according to claim 1 , wherein the organic microparticles comprise polystyrene.

8. The composite according to claim 1 , wherein the organic microparticles are in the form of polystyrene hollow spheres with a spherical equivalent diameter of 0.3 μm to 2.0 μm.

9. The composite according to claim 1 , wherein the dolomite nanoparticle composition contains more than 98 wt % dolomite mineral.

10. The composite according to claim 1 , wherein 92 to 99% of particles of the dolomite nanoparticle composition, based on the amount N of particles, have a spherical equivalent diameter in a range from 20 to 200 nm.

11. The composite according to claim 1 , wherein the dolomite is ground to the spherical equivalent diameter in one or more dry or wet grinding steps.

12. The composite according to claim 11 , wherein a ball mill, a jet plate mill, an attritor mill or combinations of such mills or combinations of one or more of such mills with a cyclone and screen is/are used for the grinding.

13. The composite according to claim 11 , wherein the dry grinding is performed in a ball mill using iron and/or porcelain balls with a diameter of 0.5 to 10 cm.

14. The composite according to claim 11 , wherein the dry grinding is performed in a ball mill using iron-cylpebs with a diameter of 2.5 cm.

15. The composite according to claim 11 , wherein the wet grinding is performed in an attritor mill using grinding balls made of zirconium silicate, zirconium dioxide and/or baddeleite with a diameter of 0.2 to 5 mm.

16. The composite according to claim 11 , wherein the wet grinding is performed in an attritor mill using grinding balls made of zirconium silicate, zirconium dioxide and/or baddeleite with a diameter of 0.2 to 2 mm.

17. The composite according to claim 11 , wherein the wet grinding is performed in an attritor mill using grinding balls made of zirconium silicate, zirconium dioxide and/or baddeleite with a diameter of 0.5 to 5 mm.

18. The composite according to claim 11 , wherein the wet grinding is performed in an attritor mill using grinding balls made of zirconium silicate, zirconium dioxide and/or baddeleite with a diameter of 0.5 to 2 mm.

19. The composite according to claim 1 , wherein the natural ground dolomite is dispersed and/or ground in the form of an aqueous slurry with a dolomite solids content of more than 10 wt %.

20. The composite according to claim 1 , wherein the natural dolomite is dispersed and/or ground in the form of an aqueous slurry with a dolomite solids content of more than 15 to 30 wt %.

21. The composite according to claim 1 , wherein the natural ground dolomite is dispersed and/or ground in the form of an aqueous slurry with a dolomite solids content of 72 to 80 wt %.

22. The composite according to claim 1 , wherein the dolomite dispersed and/or ground in the form of an aqueous slurry with a dolomite solids content of ≤60 wt %, is physically concentrated by filter pressing and/or centrifuging and/or thermally, or by combinations of mechanical and thermal concentration steps, optionally dispersed in the presence of one or more dispersants, to a final concentration of between 60 wt % and 78 wt %.

23. The composite according to claim 1 , wherein the dolomite dispersed and/or ground in the form of an aqueous slurry with a dolomite solids content of ≤60 wt %, is physically concentrated by filter pressing and/or centrifuging and/or thermally, or by combinations of mechanical and thermal concentration steps, optionally dispersed in the presence of one or more dispersants, to a final concentration of 66±2 wt %.

24. The composite according to claim 1 , wherein the grinding aids and/or dispersants are anionic grinding aids and/or dispersants.

25. The composite according to claim 24 , wherein the anionic grinding aids and/or dispersants comprise homopolymers or copolymers of polycarboxylic acid salts based on acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid or mixtures thereof, or sodium polyphosphates, sodium citrate or mixtures thereof.

26. The composite according to claim 25 , wherein the homopolymers or copolymers of polycarboxylic acid salts are partially or completely neutralized with sodium, lithium, potassium, ammonium, calcium, magnesium, strontium and/or aluminium or mixtures thereof.

27. The composite according to claim 25 , wherein the homopolymers or copolymers of polycarboxylic acid salts are partially or completely neutralized with sodium and magnesium.

28. The composite according to claim 1 , wherein the dispersants and/or grinding aids are used in wet grinding in an amount of about 0.05 to about 2 wt %.

29. The composite according to claim 1 , wherein the viscosity of the dolomite slurry in wet grinding is less than 2500 mPa s.

30. The composite according to claim 1 , wherein the viscosity of the dolomite slurry in wet grinding is in the range of 50 to 250 mPa s.

31. The composite according to claim 1 , wherein the grinding aids and/or dispersants comprise a glycol, a polyglycol, a polyethylene glycol, an ethylene oxide-propyl

Assignees

• Buri Matthias
• Gane Patrick A C
• Blum Rene Vinzenz
• Omya Int Ag

Inventors

• Buri Matthias
• Gane Patrick A C
• Blum René Vinzenz

Classifications

• C01P2004/32

  Spheres · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• C09C1/00 Primary

  Treatment of specific inorganic materials other than fibrous fillers (tenebrescent materials C09K9/00; luminescent materials C09K11/00); Preparation of carbon black · CPC title

• C09C1/42

  Clays · CPC title

• C09C1/06

  Lithopone · CPC title