Soft, absorbent sheets having high absorbency and high caliper, and methods of making soft, absorbent sheets
View Patent ↗An absorbent cellulosic sheet made by a method that includes forming an aqueous cellulosic web on a portion of a structuring fabric in a papermaking machine, and drying the cellulosic web to form the absorbent cellulosic sheet. The portion of the structuring fabric on which the cellulosic web is formed has a planar volumetric index of at least about 26. The absorbent cellulosic sheet has a caliper of at least about 160 mils/8 sheets and a dry machine direction (MD) to cross machine direction (CD) tensile ratio of less than about 1.0.
1. An absorbent cellulosic sheet made by a method that comprises:
forming an aqueous cellulosic web on a portion of a structuring fabric in a papermaking machine; and
drying the cellulosic web to form the absorbent cellulosic sheet,
wherein the portion of the structuring fabric on which the cellulosic web is formed has a planar volumetric index of at least about 26, and
wherein the absorbent cellulosic sheet (i) is two-ply, (ii) has a caliper of at least about 260 mils/8 sheets, and (iii) has a dry machine direction (MD) to cross machine direction (CD) tensile ratio of about 1.0 or less.
2. The absorbent cellulosic sheet according to claim 1 , wherein the planar volumetric index is about 26 to about 30.5.
3. The absorbent cellulosic sheet according to claim 1 , wherein the dry MD/CD tensile ratio is about 0.9 to about 1.0.
4. The absorbent cellulosic sheet according to claim 1 , wherein the planar volumetric index is about 26 to about 30.5 and the dry MD/CD tensile ratio is about 0.9 to about 1.0.
5. The absorbent cellulosic sheet according to claim 1 , wherein the structuring fabric has an adjusted planar volumetric index of at least about 27.
6. The absorbent cellulosic sheet according to claim 5 , wherein the adjusted planar volumetric index is about 27 to about 31.5.
7. The absorbent cellulosic sheet according to claim 1 , wherein the portion of the structuring fabric is formed entirely by knuckles on warp yarns of the structuring fabric.
8. The absorbent cellulosic sheet according to claim 1 , wherein the absorbent cellulosic sheet has a basis weight of about 32.0 lbs/ream or less.
9. The absorbent cellulosic sheet according to claim 1 , wherein the aqueous cellulosic web is formed using a furnish that includes cellulosic long fibers having a coarseness of at least about 15.5 mg/100 mm.
10. The absorbent cellulosic sheet according to claim 1 , wherein the absorbent cellulosic sheet has a CD Wet Tensile of at least about 620 g/3 in.
11. The absorbent cellulosic sheet according to claim 1 , wherein the method further comprises non-compactively dewatering the aqueous cellulosic web on the structuring fabric.
12. The absorbent cellulosic sheet according to claim 1 , wherein the planar volumetric index includes two variables: the contact area ratio (CAR) and the effective pocket volume (EPV).
13. The absorbent cellulosic sheet according to claim 12 , wherein the contact area ratio is defined as the ratio of the contact area formed by knuckles in the structuring fabric to an open area in the web contacting side of the structuring fabric.
14. The absorbent cellulosic sheet according to claim 13 , wherein the effective pocket volume is defined as an average volume of pockets in the structuring fabric into which cellulosic fibers of the web may migrate during a papermaking operation.
15. The absorbent cellulosic sheet according to claim 14 , wherein the planar volumetric index is defined as the contact area ratio (CAR) multiplied by the effective pocket volume (EPCV) multiplied by one hundred.
16. The absorbent cellulosic sheet according to claim 15 , wherein the adjusted planar volumetric index is about 27 to about 31. 5.