Hyperplaty clays and their use in paper coating and filling, methods for making same, and paper products having improved brightness
View Patent ↗The present invention relates to a hydrous kaolin product having improved optical properties, for example, when used in the production of paper products. The present invention comprises an improved barrier coating for paper and a method of making the coated paper. The present invention also comprises an improved method from making filled and coated paper products. The present invention uses a composition comprising kaolin having a shape factor of at least about 70:1, such as at least about 80:1 or at least about 100:1.
1. A method of making a coated paper comprising:
coating a fibrous substrate with a paper coating composition comprising a kaolin having a shape factor of at least about 70:1.
2. The method according to claim 1 , wherein the kaolin has a shape factor of at least about 80:1.
3. The method according to claim 1 , wherein the kaolin has a shape factor of at least about 90:1.
4. The method according to claim 1 , wherein the kaolin has a shape factor of at least about 100:1.
5. A method of making a filled paper comprising
providing a fibrous substrate;
adding to said substrate kaolin having a shape factor of at least about 70:1.
6. The method according to claim 5 , further comprising adding a retention aid.
7. The method according to claim 5 , wherein the kaolin has a shape factor of at least about 80:1.
8. The method according to claim 5 , wherein the kaolin has a shape factor of at least about 90:1.
9. The method according to claim 5 , wherein the kaolin has a shape factor of at least about 100:1.
10. A coated paper comprising:
a fibrous substrate; and
a coating on said substrate comprising kaolin having a shape factor of at least about 70:1.
11. The coated paper according to claim 10 , wherein the kaolin has a shape factor of at least about 80:1.
12. The coated paper according to claim 10 , wherein the kaolin has a shape factor of at least about 90:1.
13. The coated paper according to claim 10 , wherein the kaolin has a shape factor of at least about 100:1.
14. A method of improving barrier properties in paper comprising:
coating a fibrous substrate with a coating composition comprising kaolin having a shape factor of at least about 70:1.
15. The method according to claim 14 , wherein said coating further comprises a binder.
16. The method according to claim 15 , wherein said binder is a latex binder.
17. The method according to claim 15 , wherein said binder is present in an amount ranging from about 40% to about 50% by weight.
18. The method according to claim 14 , wherein the kaolin has a shape factor of at least about 80:1.
19. The method according to claim 14 , wherein the kaolin has a shape factor of at least about 90:1.
20. The method according to claim 14 , wherein the kaolin has a shape factor of at least about 100:1.
21. A barrier coating composition for paper or paperboard, comprising a slurry comprising kaolin having a shape factor of at least about 70:1, the solids content of the slurry ranging from about 45% to about 70%.
22. The barrier coating composition according to claim 21 , wherein the kaolin has a shape factor of at least about 80:1.
23. The barrier coating composition according to claim 21 , wherein the kaolin has a shape factor of at least about 90:1.
24. The barrier coating composition according to claim 21 , wherein the kaolin has a shape factor of at least about 100:1.
25. A paper coating composition for paper or paperboard, comprising:
kaolin having a shape factor of at least about 70:1; and
a binder,
wherein the composition has a solids content of at least about 60%.
26. The paper coating composition according to claim 25 , further comprising at least one additional pigment.
27. The paper coating composition according to claim 26 , wherein the at least one additional pigment is TiO 2.
28. The paper coating composition according to claim 27 , wherein the composition has a ratio of kaolin to TiO 2 of less than about 85:15 parts by weight.
29. The paper coating composition according to claim 25 , wherein the composition has a solids content of at least about 70%.
30. The paper coating composition according to claim 25 , further comprising at least one dispersant.
31. A filler composition for paper or paperboard comprising kaolin having a shape factor of at least about 70:1.
32. The filler composition according to claim 31 , wherein the kaolin has a shape factor of at least about 80:1.
33. The filler composition according to claim 31 , wherein the kaolin has a shape factor of at least about 90:1.
34. The filler composition according to claim 31 , wherein the kaolin has a shape factor of at least about 100:1.