Filler for papermaking process
The present invention relates to a filler comprising calcium salt and cellulose derivative having a degree of substitution of net ionic groups up to about 0.65, wherein the filler is substantially free from fibers or fibrils of cellulose or lignocellulose. The invention also relates to a filler comprising calcium salt and a cellulose derivative having a degree of substitution of net ionic groups up to about 0.65, wherein the cellulose derivative contains cationic groups.
1. A filler comprising calcium salt and water-soluble cellulose derivative having a degree of substitution of net anionic groups up to about 0.40, wherein the filler is substantially free from fibers or fibrils of cellulose or lignocellulose, wherein at least about 30% by weight of the cellulose derivative is absorbed on or attached to the calcium salt.
2. The filler according to claim 1 , wherein the degree of substitution is at least 0.05.
3. The filler according to claim 1 , wherein the degree of substitution is from about 0.15 to about 0.40.
4. The filler according to claim 1 wherein the cellulose derivative is a cellulose ether.
5. The filler according to claim 1 , wherein the cellulose derivative contains carboxymethyl groups.
6. The filler according to claim 1 , wherein the cellulose derivative contains quaternary ammonium groups.
7. The filler according to claim 1 , wherein the cellulose derivative is anionic.
8. The filler according to claim 1 , wherein the cellulose derivative is amphoteric.
9. The filler according to claim 1 , wherein the filler has a cellulose derivative content from 0.3% to 10% by weight, based on the weight of the solids of the filler.
10. The filler according to claim 1 , wherein the filler has a calcium salt content from 60% to about 80% by weight, based on the weight of the solids of the filler.
11. The filler according to claim 1 , wherein the calcium salt is calcium carbonate.
12. The filler according to claim 1 , wherein the calcium salt is precipitated calcium carbonate.
13. A filler comprising calcium salt and water-soluble cellulose derivative having a degree of substitution of net anionic groups up to about 0.40, wherein the cellulose derivative contains quaternary ammonium groups, and wherein the filler is substantially free from fibers or fibrils of cellulose or lignocellulose.
14. The filler according to claim 13 , wherein the degree of substitution is at least 0.05.
15. The filler according to claim 13 , wherein the degree of substitution is from about 0.15 to about 0.40.
16. The filler according to claim 13 , wherein the cellulose derivative is a cellulose ether.
17. The filler according to claim 13 , wherein the cellulose derivative contains carboxymethyl groups.
18. The filler according to claim 13 , wherein the cellulose derivative is amphoteric.
19. The filler according to claim 13 , wherein the filler has a cellulose derivative content from 0.3% to 10% by weight, based on the weight of the solids of the filler.
20. The filler according to claim 13 , wherein the filler has a calcium salt content from 60% to about 80% by weight, based on the weight of the solids of the filler.
21. The filler according to claim 13 , wherein the calcium salt is calcium carbonate.
22. The filler according to claim 13 , wherein the calcium salt is precipitated calcium carbonate.
23. The filler according to claim 1 , wherein the degree of substitution is up to about 0.30.
24. The filler according to claim 3 , wherein the degree of substitution is from about 0.15 to about 0.30.
25. The filler according to claim 13 , wherein the degree of substitution is up to about 0.30.
26. The filler according to claim 1 , wherein at least about 45% by weight of the cellulose derivative is absorbed on or attached to the calcium salt.
27. The filler according to claim 26 , wherein at least about 60% by weight of the cellulose derivative is absorbed on or attached to the calcium salt.
28. The filler according to claim 13 , wherein at least about 30% by weight of the cellulose derivative is absorbed on or attached to the calcium salt.
29. A filler comprising a calcium salt which is precipitated calcium carbonate and a water-soluble cellulose derivative which is carboxymethyl cellulose having a degree of substitution of carboxymethyl groups up to about 0.45.
30. The filler according to claim 29 , wherein the degree of substitution is at least 0.05.
31. The filler according to claim 29 , wherein the degree of substitution is from about 0.15 to about 0.40.
32. The filler according to claim 29 , wherein the filler has a cellulose derivative content from 0.3% to 10% by weight, based on the weight of the solids of the filler.
33. The filler according to claim 29 , wherein the filler has a calcium salt content from 60% to about 80% by weight, based on the weight of the solids of the filler.
34. The filler according to claim 29 , wherein the precipitated calcium carbonate has a specific surface area of from about 2 to about 20 m 2 / g.
35. The filler according to claim 34 , wherein the precipitated calcium carbonate has a specific surface area of from about 7 to about 12 m 2 / g.
36. The filler according to claim 29 , wherein at least about 45% by weight of the cellulose derivative is absorbed on or attached to the calcium salt.
37. A filler comprising a calcium salt which is calcium carbonate and a water-soluble cellulose derivative having a degree of substitution of carboxyalkyl groups up to about 0.45, wherein the calcium salt is precipitated calcium carbonate having a specific surface area of from about 7 to about 12 m 2 / g, and wherein the filler has a calcium salt content of at least 0.0001% by weight and a cellulose derivative content of at least 0.01% by weight, based on the weight of solids of the filler.
38. The filler of claim 37 , wherein the precipitated calcium carbonate has a specific surface area of from about 7 to 10 m 2 / g.