Fabric crepe/draw process for producing absorbent sheet

• US 20050217814A1
• Filed: 04/18/2005
• Published: 10/06/2005
• Est. Priority Date: 10/07/2002
• Status: Active Grant

• Current Assignee: GPCP IP Holdings LLC
• Original Assignee: Georgia-Pacific Consumer Products LP (KOCH Industries Incorporated)
• Inventors: Super, Guy H., McCullough, Stephen J., Edwards, Steven L., Murray, Frank C.
• Granted Patent: US 7,789,995 B2
• Time in Patent Office: Days
• US Class Current: 162/111
• CPC Class Codes: A47K 10/02 Towels made of paper A47K10/16; woven fabrics D03D; non-woven fabrics D04H
• CPC Class Codes: B31F 1/126 including making of the paper to be crêped
• CPC Class Codes: B31F 1/16 by elastic belts B31F1/18 takes precedence
• CPC Class Codes: D21F 11/006 Making patterned paper
• CPC Class Codes: D21H 11/14 Secondary fibres working-up waste paper D21C5/02
• CPC Class Codes: D21H 21/20 Wet strength agents
• CPC Class Codes: D21H 25/005 Mechanical treatment D21H25/08, D21H25/18 take precedence
• CPC Class Codes: D21H 27/005 relating to physical or mechanical properties, e.g. tensile strength, stretch, softness
• CPC Class Codes: D21H 27/007 relating to absorbency, e.g. amount or rate of water absorption, optionally in combination with other parameters relating to physical or mechanical properties
• CPC Class Codes: D21H 27/02 Patterned paper patterned coatings D21H19/66; embossing B31F1/07; prepared on the paper-making machines D21F11/00
• CPC Class Codes: D21H 27/40 at least one of the sheets being non-planar, e.g. crêped crêping or corrugating paper B31F
• CPC Class Codes: Y10T 428/24455 Paper

Abstract

A method of making a fabric-creped absorbent cellulosic sheet comprising: a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber; b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed; c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a patterned creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum.

Claims

1. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber;

b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed; and

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a patterned creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum having a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight, interconnected by way of (ii) a plurality of lower local basis weight linking regions;

wherein the drawable reticulum of the web is characterized in that it comprises a cohesive fiber matrix capable of increases in void volume when dried and subsequently drawn.

2. The method of making a fabric-creped absorbent cellullosic sheet according to claim 1, including drawing the dried web and increasing the bulk of the web.

3. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, including drawing the dried web and decreasing the sidedness of the web.

4. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, including drawing the dried web and attenuating the fiber-enriched regions of the web.

5. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, wherein the fabric creping and processing parameters are controlled such that the orientation of fibers in the fiber-enriched regions are biased in the CD.

6. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, wherein the fiber-enriched regions have a plurality of microfolds with fold lines extending transverse to the machine-direction, and further including drawing the dried web in the machine direction to expand the microfolds.

7. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, operated at a fabric crepe of from about 10 to about 300%.

8. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, operated at a fabric crepe of at least about 40%.

9. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, operated at a fabric crepe of at least about 60%.

10. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, operated at a fabric crepe of at least about 80%.

11. The method of making a fabric-creped absorbent cellulosic sheet according to claim 1, operated at a fabric crepe of 100% or more.

12. The method of making a fabric-creped absorbent cellulosic sheet according to claim 11, operated at a fabric crepe of at least about 125%.

13. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber;

b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed;

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a patterned creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum having a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight, interconnected by way of (ii) a plurality of lower local basis weight linking regions;

wherein the drawable reticulum of the web is characterized in that it comprises a cohesive fiber matrix capable of increases in void volume upon dry-drawing,

d) applying the web to a drying cylinder;

e) drying the web on the drying cylinder;

f) removing the web from the drying cylinder;

wherein steps (d), (e) and (f) are performed so as to substantially preserve the drawable fiber reticulum, and

g) drawing the dried web.

14. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the drying cylinder is a Yankee dryer.

15. The method of making a fabric-creped absorbent cellulosic sheet according to claim 14, wherein the web is removed from the Yankee dryer without substantial creping.

16. The method of making a fabric-creped absorbent cellulosic sheet according to claim 14, wherein subsequent to startup, the web is removed from the Yankee dryer without a creping blade.

17. The method according to claim 13, operated at a fabric crepe of from about 10% to about 100% and a crepe recovery of from about 10% to about 100%.

18. The method according to claim 13, operated at a crepe recovery of at least about 20%.

19. The method according to claim 13, operated at a crepe recovery of at least about 30%.

20. The method according to claim 13, operated at a crepe recovery of at least about 40%.

21. The method according to claim 13, operated at a crepe recovery of at least about 50%.

22. The method according to claim 13, operated at a crepe recovery of at least about 60%.

23. The method according to claim 13, operated at a crepe recovery of at least about 80%.

24. The method according to claim 13, operated at a crepe recovery of at least about 95%.

25. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the web comprises secondary fiber.

26. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the step of creping the web from the transfer surface is carried out with a creping fabric.

27. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the web is drawn on-line.

28. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the web is drawn between a first roll operated at a machine-direction velocity greater than the creping fabric velocity and a second roll operated at a machine-direction velocity greater than the first roll.

29. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the dried web is calendered on-line.

30. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the web is dried to a consistency of at least about 90% prior to drawing.

31. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the web is dried to a consistency of at least about 92% prior to drawing.

32. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the fabric creping and processing parameters are controlled such that the ratio of percent decrease in caliper/percent decrease in basis weight of the web is less than about 0.85 upon drawing the web.

33. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the fabric creping and processing parameters are controlled such that the ratio of percent decrease in caliper/percent decrease in basis weight of the web is less than about 0.7 upon drawing the web.

34. The method of making a fabric-creped absorbent cellulosic sheet according to claim 13, wherein the fabric creping and processing parameters are controlled such that the ratio of percent decrease in caliper/percent decrease in basis weight of the web is less than about 0.6 upon drawing the web.

35. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber;

b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed;

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a patterned creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum having a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight, interconnected by way of (ii) a plurality of lower local basis weight linking regions;

wherein the drawable reticulum of the web is characterized in that it comprises a cohesive fiber matrix capable of increases in void volume upon dry-drawing,

d) applying the web to a drying cylinder;

e) drying the web on the drying cylinder;

f) peeling the web from the drying cylinder;

g) controlling the takeaway angle of the web from the drying cylinder;

wherein steps (d), (e), (f) and (g) are performed so as to substantially preserve the drawable fiber reticulum, and

h) drawing the dried web.

36. The method according to claim 35, wherein the step of controlling the takeaway angle from the drying cylinder is carried out utilizing a sheet control cylinder.

37. The method according to claim 36, wherein the sheet control cylinder is disposed adjacent the drying cylinder such that the gap between the surface of the drying cylinder and the surface of the sheet control cylinder is less than about twice the thickness of the web.

38. The method according to claim 37, wherein the sheet control cylinder is disposed adjacent the dying cylinder such that the gap between the surface of the drying cylinder and the surface of the sheet control cylinder is about the thickness of the web or less.

39. The method according to claim 35, wherein the web is drawn on-line after being peeled from the drying cylinder.

40. The method according to claim 39, wherein the web is drawn by at least about 10%.

41. The method according to claim 39, wherein the web is drawn by at least about 15%.

42. The method according to claim 39, wherein the web is drawn by at least about 30%.

43. The method according to claim 39, wherein the web is drawn by at least about 45%.

44. The method according to claim 39, wherein the web is drawn by at least about 75%.

45. The method of making a fabric-creped absorbent cellulosic sheet according to claim 35, wherein the web is drawn between a first draw roll operated at a machine-direction velocity greater than the creping fabric velocity and a second draw roll operated at a machine-direction velocity greater than the first draw roll.

46. The method according to claim 45, wherein the web wraps the first draw roll over more than 180°

of its circumference.

47. The method according to claim 46, wherein the web wraps the second draw roll over more than 180°

of its circumference.

48. The method according to claim 45, wherein the web wraps each of the first and second draw rolls over from about 200°

to about 300°

of their respective circumferences.

49. The method according to claim 45, wherein said first and second draw rolls are movable with respect to each other.

50. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber;

b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed;

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a patterned creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum having a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight, interconnected by way of (ii) a plurality of lower local basis weight linking regions;

wherein the drawable reticulum of the web is characterized in that it comprises a cohesive fiber matrix capable of increases in void volume upon dry-drawing,

d) adhering the web to a drying cylinder with a resinous adhesive coating composition;

e) drying the web on the drying cylinder;

f) removing the web from the drying cylinder;

wherein steps (d), (e) and (f) are preformed so as to substantially preserve the drawable fiber reticulum, and

g) drawing the dried web.

51. The method of making a fabric-creped absorbent cellulosic sheet according to claim 50, wherein the web is removed from the drying cylinder without substantial creping.

52. The method of making a fabric-creped absorbent cellulosic sheet according to claim 50, wherein the web is removed from the drying cylinder subsequent to startup without a creping blade.

53. The method of making a fabric-creped absorbent cellulosic sheet according to claim 50, wherein the web is peeled from the drying cylinder while controlling its takeaway angle with a sheet control cylinder.

54. The method of making a fabric-creped absorbent sheet according to claim 50, wherein the drying cylinder is provided with a resinous protective coating layer.

55. The method of making a fabric-creped absorbent sheet according to claim 54, wherein the resinous protective coating layer comprises a polyamide resin.

56. The method of making a fabric-creped absorbent sheet according to claim 55, wherein the polyamide resin is cross-linked.

57. The method of making a fabric-creped absorbent sheet according to claim 50, wherein the resinous adhesive coating composition is re-wettable.

58. The method of making a fabric-creped absorbent sheet according to claim 50, further including the step of maintaining the adhesive resin coating composition on the drying cylinder such that it provides sufficient wet tack strength upon transfer of the web to the drying cylinder to secure the web thereto during drying, and wherein the adhesive coating composition is maintained pliant during drying such that the web may be removed from the drying cylinder without a creping blade.

59. The method of making a fabric-creped absorbent sheet according to claim 50, wherein the adhesive coating composition comprises a polyvinyl alcohol resin.

60. The method of making a fabric-creped absorbent sheet according to claim 59, wherein the adhesive coating composition includes at least one resin in addition to the polyvinyl alcohol resin.

61. The method of making a fabric-creped absorbent sheet according to claim 50, wherein the adhesive coating composition comprises a polysaccharide resin.

62. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber;

b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed;

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a patterned creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric, wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum having a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight, interconnected by way of (ii) a plurality of lower local basis weight linking regions;

wherein the drawable reticulum of the web is characterized in that it comprises a cohesive fiber matrix capable of increases in void volume upon dry-drawing,

d) applying the web to a drying cylinder;

e) embossing the web while it is disposed on the drying cylinder;

f) drying the web on the drying cylinder;

g) removing the web from the drying cylinder;

wherein steps (d), (e), (f (and (g) are performed so as to substantially preserve the drawable fiber reticulum, and

h) drawing the dried web.

63. The method of making a fabric-creped absorbent sheet according to claim 62, wherein the web is embossed when its consistency is less than about 80%.

64. The method of making a fabric-creped absorbent sheet according to claim 62, wherein the web is embossed when its consistency is less than about 70%.

65. The method of making a fabric-creped absorbent sheet according to claim 62, wherein the web is embossed when its consistency is less than about 50%.

66. The method of making a fabric-creped absorbent sheet according to claim 62, wherein the step of embossing the web while it is applied to the drying cylinder is carried out with an embossing surface traveling in the machine direction at speed slower than the speed of the drying cylinder.

67. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) compactively dewatering a papermaking furnish to form a nascent web having an apparently random distribution of papermaking fiber;

b) applying the dewatered web having the apparently random fiber distribution to a translating transfer surface moving at a first speed; and

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric to form a web with a drawable reticulum having a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight, interconnected by way of (ii) a plurality of lower local basis weight linking regions; and

d) applying vacuum to the web to increase its CD stretch by at least about 5% with respect to a like web produced by like means, but without applied vacuum after fabric creping.

68. The method according to claim 67, wherein vacuum is applied to the web while it is held in the creping fabric and the creping fabric is selected to increase CD stretch when vacuum is applied to the web.

69. The method according to claim 67, wherein at least 5 inches Hg of vacuum is applied.

70. The method according to claim 67, wherein at least 10 inches Hg of vacuum is applied.

71. The method according to claim 67, wherein at least 15 inches Hg of vacuum is applied.

72. The method according to claim 67, wherein at least 20 inches Hg of vacuum is applied.

73. The method according to claim 67, wherein at least 25 inches Hg of vacuum is applied.

74. The method according to claim 67, wherein applying vacuum to the web increases the CD stretch of the web by at least about 7.5 percent with respect to a like web produced by the same means, but without having vacuum applied thereto after fabric creping.

75. The method according to claim 67, wherein applying vacuum to the web increases the CD stretch of the web by at least about 10 percent with respect to a like web produced by the same means, but without having vacuum applied thereto after fabric creping.

76. The method according to claim 67, wherein applying vacuum to the web increases the CD stretch of the web by at least about 20 percent with respect to a like web produced by the same means, but without having vacuum applied thereto after fabric creping.

77. The method according to claim 67, wherein applying vacuum to the web increases the CD stretch of the web by at least about 35 percent with respect to a like web produced by the same means, but without having vacuum applied thereto after fabric creping.

78. The method according to claim 67, wherein applying vacuum to the web increases the CD stretch of the web by at least about 50 percent with respect to a like web produced by the same means, but without having vacuum applied thereto after fabric creping.

79. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) applying a jet of papermaking furnish to a forming wire, the jet having a jet velocity and the wire moving at a forming wire velocity, the difference between the jet velocity and forming wire velocity being referred to as the jet/wire velocity delta;

b) compactively dewatering the papermaking furnish to form a nascent web;

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric;

d) drying the web; and

e) controlling the jet/wire velocity delta and fabric creping step including fabric selection such that the dry MD/CD tensile ratio of the dried web is about 1.5 or less.

80. The method according to claim 79, including controlling the jet/wire velocity delta and the fabric creping step such that the dry MD/CD tensile ratio of the dried web is about 1 or less.

81. The method according to claim 79, including controlling the jet/wire velocity delta and the fabric creping step such that the dry MD/CD tensile ratio of the dried web is about 0.75 or less.

82. The method according to claim 79, including controlling the jet/wire velocity delta and the fabric creping step such that the dry MD/CD tensile ratio of the dried web is about 0.5 or less.

83. The method according to claim 79, including controlling the jet/wire velocity delta to be greater than about 300 fpm.

84. The method according to claim 79, including controlling the jet/wire velocity delta to be greater than about 350 fpm.

85. The method according to claim 79, including controlling the jet/wire velocity delta to be less than about 50 fpm.

86. The method according to claim 79, including controlling the jet/wire velocity delta to be less than 0 fpm, such that the forming wire speed exceeds the jet velocity.

87. A method of making a fabric-creped absorbent cellulosic sheet comprising:

a) applying a jet of papermaking furnish to a forming wire, the jet having a jet velocity and the wire moving at a forming wire velocity, the difference between the jet velocity and forming wire velocity being referred to as the jet/wire velocity delta;

b) compactively dewatering the papermaking furnish to form a nascent web;

c) fabric-creping the web from the transfer surface at a consistency of from about 30 to about 60 percent utilizing a creping fabric, the creping step occurring under pressure in a fabric creping nip defined between the transfer surface and the creping fabric wherein the fabric is traveling at a second speed slower than the speed of said transfer surface, the fabric pattern, nip parameters, velocity delta and web consistency being selected such that the web is creped from the transfer surface and redistributed on the creping fabric;

d) drying the web; and

e) controlling the jet/wire velocity delta and fabric creping step including fabric selection such that the dry MD/CD tensile ratio of the dried web is about 1.5 or less, with the proviso that the jet/wire velocity delta;

(i) is negative or (ii) is greater than about 350 fpm.

88. The method according to claim 87, wherein the jet/wire velocity delta is greater than about 400 fpm.

89. The method according to claim 87, wherein the jet/wire velocity delta is greater than about 450 fpm.

90. The method according to claim 87, wherein the web has a reticulum with a plurality of interconnected regions of different local basis weights including at least (i) a plurality of fiber enriched regions of high local basis weight by way of (ii) a plurality of lower local basis weight linking regions.