Process for manufacturing calcium carbonate materials having a particle surface with improved adsorption properties
The invention relates to a process for manufacturing calcium carbonate materials having a particle surface with improved adsorption properties of dispersant, using at least one lithium ion-containing compound, the calcium carbonate material obtained by this process, the use of the calcium carbonate materials in paper, paints and plastics, as well as the use of the lithium ion-containing compounds in the manufacturing process.
1. A calcium carbonate material comprising (i) calcium carbonate; (ii) a totally neutralized polyacrylic acid dispersing agent, (iii) 0.0035 wt % to 1 wt %, based on the total dry weight of the calcium carbonate material, of at least one lithium ion containing compound selected from the group consisting of lithium hydroxide, lithium oxide, an inorganic monomeric lithium salt, an organic monomeric lithium salt, lithium carbonate, a lithium sulphate, lithium citrate, lithium hydrogen carbonate, lithium acetate, lithium chloride, a lithium phosphate, and any mixture thereof, and (iv) water, wherein the calcium carbonate material has a solids content of 45 to 82 wt. %, and wherein the totally neutralized polyacrylic acid dispersing agent is not the lithium ion containing compound.
2. The calcium carbonate material according to claim 1 , wherein the lithium ion concentration is from 10 to 2000 ppm based on the total dry weight of the calcium carbonate material.
3. The calcium carbonate material according to claim 1 , wherein the lithium ion concentration is from 100 to 1000 ppm based on the total dry weight of the calcium carbonate material.
4. The calcium carbonate material according to claim 1 , wherein the lithium ion concentration is from 200 to 800 ppm based on the total dry weight of the calcium carbonate material.
5. The calcium carbonate material according to claim 1 , which contains the at least one lithium ion-containing compound in an amount of from 0.0035 wt % to 0.5 wt %, based on the total dry weight of the calcium carbonate material.
6. The calcium carbonate material according to claim 1 , which contains the at least one lithium ion-containing compound in an amount of from 0.02 wt % to 0.2 wt %, based on the total dry weight of the calcium carbonate material.
7. The calcium carbonate material according to claim 1 , which has a d 50 of from 0.2 to 5 μm as determined using a Sedigraph 5100™.
8. The calcium carbonate material according to claim 1 , which has a d 50 of from 0.2 to 1.5 μm as determined using a Sedigraph 5100™.
9. The calcium carbonate material according to claim 1 , which has a d 50 of from 0.25 to 1 μm as determined using a Sedigraph 5100™.
10. The calcium carbonate material according to claim 1 , which has a d 50 of from 0.45 to 0.7 μm as determined using a Sedigraph 5100™.
11. The calcium carbonate material according to claim 1 , which comprises a fraction of particles finer than 1 μm of more than 50 wt %, based on the total weight of ground material.
12. The calcium carbonate material according to claim 1 , which comprises a fraction of particles finer than 1 μm of more than 80 wt %, based on the total weight of ground material.
13. The calcium carbonate material according to claim 1 , which comprises a fraction of particles finer than 1 μm of more than 85 wt %, based on the total weight of ground material.
14. The calcium carbonate material according to claim 1 , which comprises a fraction of particles finer than 1 μm of more than 90 wt %, based on the total weight of ground material.
15. The calcium carbonate material according to claim 1 , which comprises a fraction of particles finer than 1 μm of more than 95 wt %, based on the total weight of ground material.
16. The calcium carbonate material according to claim 1 , which has a scattering coefficient S of ≧120 m 2 /kg for a coating weight of 20 g/m 2 and a Brookfield™ viscosity of <1000 mPa·s.
17. The calcium carbonate material according to claim 1 , which has a scattering coefficient S of ≧140 m 2 /kg for a coating weight of 20 g/m 2 and a Brookfield™ viscosity of <500 mPa·s.
18. The calcium carbonate material according to claim 1 , having a Brookfield™ viscosity after 1 hour of production of below 2000 mPa·s measured for one minute of stirring at 21° C. at a rotation speed of 100 rpm, and a Brookfield™ viscosity after 8 days of unstirred storage of below 2000 mPa·s measured for one minute of stirring at 21° C. at a rotation speed of 100 rpm.
19. The calcium carbonate material according to claim 1 , wherein the inorganic monomeric lithium salt or the organic monomeric lithium salt is a lithium monovalent acid salt or a lithium polyvalent acid salt.
20. Paper comprising the calcium carbonate material according to claim 1 .
21. A plastic comprising the calcium carbonate material according to claim 1 .
22. A paint comprising the calcium carbonate material according to claim 1 .