Kaolin clay pigments

1 . A high brightness, high opacifying, high bulking pigment which is comprised of kaolin clay and a minor amount of gypsum, wherein the amount of gypsum is from about 0.05 to about 0.9 weight percent based on the weight of the dry pigment.

2 . A pigment as defined by claim 1 wherein the kaolin clay is hydrous kaolin clay.

3 . A pigment as defined by claim 1 wherein the kaolin clay is calcined kaolin clay.

4 . A pigment as defined by claim 1 wherein the kaolin clay is a blend of hydrous kaolin clay and calcined kaolin clay.

5 . A pigment is defined by claim 1 which additionally comprises calcium carbonate, titanium dioxide, talc or a mixture of two or more of these materials.

6 . A pigment as defined by claim 5 wherein the calcium carbonate is ground calcium carbonate.

7 . A pigment as defined by claim 5 wherein the calcium carbonate is precipitated calcium carbonate.

8 . A pigment as defined by claim 1 wherein the amount of gypsum is from about 0.2 to about 0.8 weight percent based on the weight of the dry pigment.

9 . A pigment is defined by claim 1 wherein the amount of gypsum is from about 0.3 to about 0.5 weight percent based on the weight of the dry pigment.

10 . A high brightness, high opacifying, high bulking paper coating composition which comprises a kaolin clay pigment, a minor amount of gypsum and at least one binding material, wherein the amount of gypsum is from about 0.05 to about 0.9 weight percent based on the weight of the dry pigment.

11 . A paper coating composition as defined by claim 10 wherein the pigment is comprised of hydrous kaolin clay.

12 . A paper coating composition as defined by claim 10 wherein the pigment is comprised of calcined kaolin clay.

13 . A paper coating composition as defined by claim 10 wherein the pigment is comprised of a blend of hydrous kaolin clay and calcined kaolin clay.

14 . A paper coating composition as defined by claim 10 which additionally comprises calcium carbonate, titanium dioxide, talc or a mixture of two or more of these materials.

15 . A paper coating composition as defined by claim 14 wherein the calcium carbonate is ground calcium carbonate.

16 . A paper coating composition as defined by claim 14 wherein the calcium carbonate is precipitated calcium carbonate.

17 . A paper coating composition as defined by claim 10 wherein the amount of gypsum is from about 0.2 to about 0.8 weight percent based on the weight of the dry pigment.

18 . A paper coating composition as defined by claim 10 wherein the amount of gypsum is from about 0.3 to about 0.5 based on the weight of the dry pigment.

19 . A paper coating composition as defined by claim 10 wherein the binding material is a starch, protein, water soluble polymer, latex or a mixture of two or more of these materials.

20 . A paper coating composition as defined by claim 19 wherein the binding material is polyvinyl alcohol, styrene butadiene latex, polyvinyl acetate, styrene acrylate, styrene acrylonitrile or a mixture of two or more of these materials.

21 . A process for making a high brightness, high opacifying, high bulking pigment, wherein the process comprises adding a minor amount of gypsum to kaolin clay, wherein the amount of gypsum is from about 0.05 to about 0.9 based on the weight of the dry pigment.

22 . A process as defined by claim 21 wherein the kaolin clay is hydrous kaolin clay.

23 . A process as defined by claim 21 wherein the kaolin clay is calcined kaolin clay.

24 . A process as defined by claim 21 wherein the kaolin clay is a blend of hydrous kaolin clay and calcined kaolin clay.

25 . A process as defined by claim 21 wherein the amount of gypsum is from about 0.2 to about 0.8 weight percent based on the weight of the dry pigment.

26 . A process as defined by claim 21 wherein the amount of gypsum is from about 0.3 to about 0.5 weight percent based on the weight of the dry pigment.

27 . A process as defined by claim 21 wherein the pigment additionally comprises calcium carbonate, titanium dioxide, talc or a mixture of two or more of these materials.

28 . A process as defined by claim 27 wherein the calcium carbonate is ground calcium carbonate.

29 . A process as defined by claim 27 wherein the calcium carbonate is precipitated calcium carbonate.

30 . A process for producing a paper coating composition, wherein the process comprises mixing a minor amount of gypsum, a kaolin clay pigment and at least one binding material, wherein the amount of gypsum is from about 0.05 to about 0.9 weight percent based on the weight of the dry pigment.

31 . A process as defined by claim 30 wherein the kaolin clay is hydrous kaolin clay.

32 . A process as defined by claim 30 wherein the kaolin clay is calcined kaolin clay.

33 . A process as defined by claim 30 wherein the kaolin clay is a blend of hydrous kaolin clay and calcined kaolin clay.

34 . A process as defined by claim 30 wherein the paper coating composition additionally comprises calcium carbonate, titanium dioxide, talc or a mixture of two or more of the materials.

35 . A process as defined by claim 34 wherein the calcium carbonate is ground calcium carbonate.

36 . A process as defined by claim 34 wherein the calcium carbonate is precipitated calcium carbonate.

37 . A process as defined by claim 30 wherein the amount of gypsum is from about 0.2 to about 0.8 weight percent based on the weight of the dry pigment.

38 . A process as defined by claim 30 wherein the amount of gypsum is from about 0.3 to about 0.5 weight percent based on the weight of the dry pigment.

39 . A paper coated with a high brightness, high opacifying, high bulking pigment which is comprised of kaolin clay and a minor amount of gypsum, wherein the amount of gypsum is from about 0.05 to about 0.9 based on the weight of the dry pigment.

40 . A paper coated with a pigment as defined by claim 39 wherein the kaolin clay is hydrous kaolin clay.

41 . A paper coated with a pigment as defined by claim 39 wherein the kaolin clay is calcined kaolin clay.

42 . A paper coated with a pigment as defined by claim 39 wherein the kaolin clay is a blend of hydrous kaolin clay and calcined kaolin clay.

43 . A paper coated with a pigment as defined by claim 39 wherein the pigment additionally comprises calcium carbonate, titanium dioxide, talc or a mixture of two or more of these materials.

44 . A paper coated with a pigment as defined by claim 43 wherein the calcium carbonate is ground calcium carbonate.

45 . A paper coated with a pigment as defined by claim 43 wherein the calcium carbonate is precipitated calcium carbonate.

46 . A paper coated with a pigment as defined by claim 39 wherein the amount of gypsum is from about 0.2 to about 0.8 weight percent based on the weight of the dry pigment.

47 . A paper coated with a pigment as defined by claim 39 wherein the amount of gypsum is from about 0.3 to about 0.5 weight percent based on the weight of the dry pigment.

48 . A paper coated with a high brightness, high opacifying, high bulking coating composition which comprises a kaolin clay pigment, a minor amount of gypsum and at least one binding material wherein the amount of gypsum is from about 0.05 to about 0.9 weight percent based on the weight of the dry pigment.

49 . A coated paper as defined by claim 48 wherein the kaolin clay is hydrous kaolin clay.

50 . A coated paper as defined by claim 48 wherein the kaolin clay is calcined kaolin clay.

51 . A coated paper as defined by claim 48 wherein the kaolin clay is a blend of hydrous kaolin clay and calcined kaolin clay.

52 . A coated paper as defined by claim 48 wherein the coating composition additionally comprises calcium carbonate, titanium dioxide, talc or a mixture of two or more of these materials.

53 . A coated paper as defined by claim 52 wherein the calcium carbonate is ground calcium carbonate.

54 . A coated paper as defined by claim 52 wherein the calcium carbonate is precipitated calcium carbonate.

55 . A coated paper as defined by claim 48 wherein the amount of gypsum is from about 0.2 to about 0.8 weight percent based on the weight of the dry pigment.

56 . A coated paper as defined by claim 48 wherein the amount of gypsum is from about 0.3 to about 0.5 weight percent based on the weight of the dry pigment.