Process for the preparation of a mineral filler product

Patent metadata

Field	Value
Publication number	US-10119032-B2
Application number	US-201515116373-A
Country	US
Kind code	B2
Filing date	Feb 13, 2015
Priority date	Feb 21, 2014
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

A process for the preparation of a mineral filler product is disclosed, the process comprising a step of wet grinding a calcium carbonate-containing material in a mixture obtained by contacting the calcium carbonate-containing material with at least one grinding agent selected from specific styrene-maleic anhydride co-polymers and/or specific derivatives of styrene-maleic anhydride co-polymers.

First claim

The invention claimed is:

1. A process for the preparation of a mineral filler product, the process comprising the steps of:
a) providing a calcium carbonate-containing material;
b) providing water;
c) providing at least one grinding agent;
d) wet grinding the calcium carbonate-containing material in a mixture obtained by contacting:
i) the calcium carbonate-containing material provided in step a), with
ii) the water provided in step b), and with
iii) the at least one grinding agent provided in step c) in any order in at least one grinding unit to obtain a wet ground mineral filler;

e) optionally classifying the wet ground mineral filler of step d) to obtain a coarse fraction and a fine fraction, wherein the coarse fraction is removed or subjected to wet grinding step d) and the fine fraction represents a fine mineral filler;
f) drying the wet ground mineral filler of step d) and/or the fine mineral filler of step e) to obtain a dried mineral filler having a total moisture content of less than or equal to 1.0 wt.-%, based on the total weight of said dried mineral filler; and
g) treating the dried mineral filler of step f) with a hydrophobizing agent to obtain a surface-treated product having a treatment layer on at least part of the surface of said product;
wherein the total moisture content in the mixture of step d) ranges from 15.0 to 50.0 wt.-%, based on the total weight of said mixture;
the amount of the at least one grinding agent provided in step c) ranges from 0.01 to 10.0 wt.-%, based on the total dry weight of the calcium carbonate-containing material;
the temperature in step d) ranges from 60° C. to 150° C.; and
the at least one grinding agent is selected from the group consisting of styrene-maleic anhydride co-polymers and derivatives of styrene-maleic anhydride co-polymers, said derivatives being selected from styrene-maleic anhydride co-polymers having partially or fully hydrolyzed maleic anhydride units, wherein said grinding agent has a monomer unit ratio (styrene units:maleic anhydride units, S:MA) of from 1:2 to 5:1 and a molecular weight M W of from 500 to 40,000 g/mol.

2. The process according to claim 1 , wherein the calcium carbonate-containing material provided in step a) is natural calcium carbonate.

3. The process according to claim 1 , wherein the calcium carbonate-containing material provided in step a) is selected from the group consisting of marble, limestone, chalk, dolomite, and any mixture thereof.

4. The process according to claim 1 , wherein the at least one grinding agent provided in step c) has a monomer unit ratio (S:MA) of from 1:1 to 4:1.

5. The process according to claim 1 , wherein the at least one grinding agent provided in step c) has a monomer unit ratio (S:MA) of from 1:1 to 3:1.

6. The process according to claim 1 , wherein the at least one grinding agent provided in step c) has a monomer unit ratio (S:MA) of from 1:1 to 2:1.

7. The process according to claim 1 , wherein the at least one grinding agent provided in step c) has a molecular weight M W of from 2,000 to 30,000 g/mol.

8. The process according to claim 1 , wherein the at least one grinding agent provided in step c) has a molecular weight M W of from 4,000 to 8,000 g/mol.

9. The process according to claim 1 , wherein the at least one grinding agent provided in step c) is partially or fully neutralized with cations selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, ammonium, iminium, and any mixture thereof.

10. The process according to claim 1 , wherein the total moisture content in the mixture of step d) ranges from 18.0 to 35.0 wt.-%, based on the total weight of said mixture.

11. The process according to claim 1 , wherein the total moisture content in the mixture of step d) ranges from 20.0 to 28.0 wt.-%, based on the total weight of said mixture.

12. The process according to claim 1 , wherein the total moisture content in the mixture of step d) ranges from 22.0 to 25.0 wt.-%, based on the total weight of said mixture.

13. The process according to claim 1 , wherein the temperature in step d) ranges from 65° C. to 125° C.

14. The process according to claim 1 , wherein the temperature in step d) ranges from 70° C. to 115° C.

15. The process according to claim 1 , wherein the temperature in step d) ranges from 75° C. to 105° C.

16. The process according to claim 1 , wherein the wet ground mineral filler of step d) has a weight median particle d 50 ranging from 0.1 to 8.0 μm.

17. The process according to claim 1 , wherein the wet ground mineral filler of step d) has a weight median particle d 50 ranging from 0.2 to 5.0 μm.

18. The process according to claim 1 , wherein the wet ground mineral filler of step d) has a weight median particle d 50 ranging from 0.4 to 3.0 μm.

19. The process according to claim 1 , wherein the dried mineral filler of step f) has a total moisture content of less than or equal to 0.5 wt.-%, based on the total weight of said dried mineral filler.

20. The process according to claim 1 , wherein the dried mineral filler of step f) has a total moisture content of less than or equal to 0.2 wt.-%, based on the total weight of said dried mineral filler.

21. The process according to claim 1 , wherein the dried mineral filler of step f) has a total moisture content of between 0.03 and 0.07 wt.-%, based on the total weight of said dried mineral filler.

22. The process according to claim 1 , wherein the hydrophobizing agent of step g) is selected from the group consisting of fatty acids having from 6 to 24 chain carbon atoms, mono-substituted succinic anhydrides, alkyl phosphoric acid esters, polyhydrogensiloxane, polydimethylsiloxane, and any mixture thereof.

Assignees

• Omya Int Ag

Inventors

• Rentsch Samuel
• Ippolito Fabio
• Buri Matthias
• Gane Patrick A C

Classifications

• C08K2003/265

  Calcium, strontium or barium carbonate · CPC title

• C08K9/04

  Ingredients treated with organic substances {(treated with macromolecular compounds C08K9/08)} · CPC title

• C08K2201/005

  Additives being defined by their particle size in general · CPC title

• C09C1/021 Primary

  Calcium carbonates · CPC title

• C09C3/041

  Grinding · CPC title