초록 ▼

A method for making a dispersible nonwoven sheet generally comprises dispersing natural fibers and regenerated fibers in a ratio of about 70 to about 90 percent by weight natural fibers and about 10 to about 30 percent by weight regenerated fibers in a liquid medium to form a liquid suspension. The

A method for making a dispersible nonwoven sheet generally comprises dispersing natural fibers and regenerated fibers in a ratio of about 70 to about 90 percent by weight natural fibers and about 10 to about 30 percent by weight regenerated fibers in a liquid medium to form a liquid suspension. The liquid suspension is deposited over a foraminous forming wire to form a nonwoven tissue web. The nonwoven tissue web is sprayed with a first plurality of jets. Each jet of the first plurality of jets is spaced from an adjacent one of the first plurality of jets by a first distance. The nonwoven tissue web also is sprayed with a second plurality of jets. Each jet of the second plurality of jets is spaced from an adjacent one of the second plurality of jets by a second distance, and the second distance is less than the first distance. The nonwoven tissue web is dried to form the dispersible nonwoven sheet.

대표청구항 ▼

1. A method for making a dispersible nonwoven sheet, the method comprising: dispersing natural fibers and regenerated fibers in a ratio of about 70 to about 90 percent by weight natural fibers and about 10 to about 30 percent by weight regenerated fibers in a liquid medium to form a liquid suspensio

1. A method for making a dispersible nonwoven sheet, the method comprising: dispersing natural fibers and regenerated fibers in a ratio of about 70 to about 90 percent by weight natural fibers and about 10 to about 30 percent by weight regenerated fibers in a liquid medium to form a liquid suspension, wherein the consistency of the liquid suspension is between about 0.02 and about 0.08 percent fiber by weight;depositing the liquid suspension over a foraminous forming wire to form a nonwoven tissue web;spraying the nonwoven tissue web with one of a first plurality of liquid jets to displace a first region of natural and regenerated fibers in an axis perpendicular to the plane of the nonwoven tissue web;spraying the nonwoven tissue web with an adjacent one of the first plurality of liquid jets to displace a second region of natural and regenerated fibers in an axis perpendicular to the plane of the nonwoven tissue web, each liquid jet of the first plurality of liquid jets being spaced from an adjacent one of the first plurality of liquid jets by a first distance, the natural and regenerated fibers displaced in the second region do not overlap with natural and regenerated fibers in the first region;spraying the nonwoven tissue web with a second plurality of liquid jets, each liquid jet of the second plurality of liquid jets being spaced from an adjacent one of the second plurality of liquid jets by a second distance, wherein the second distance is less than the first distance, the second plurality of liquid jets substantially hydroentangles the natural and regenerated fibers in both the first and second regions of the natural and regenerated fibers; anddrying the nonwoven tissue web to form the dispersible nonwoven sheet. 2. The method set forth in claim 1 wherein the first spacing is such that a region of fibers displaced by each liquid jet of the first plurality of liquid jets does not overlap substantially with a region of fibers displaced by the adjacent one of the first plurality of liquid jets. 3. The method set forth in claim 2 wherein the second spacing is such that a region of fibers displaced by each liquid jet of the second plurality of liquid jets becomes hydroentangled with a region of fibers displaced by an adjacent one of the second plurality of liquid jets. 4. The method set forth in claim 1 wherein the first spacing is between about 1200 micrometers and about 2400 micrometers, and a diameter of an orifice of each liquid jet of the first plurality of liquid jets is between about 90 micrometers and about 150 micrometers. 5. The method set forth in claim 4 wherein the first spacing is about 1800 micrometers and a diameter of an orifice of each liquid jet of the first plurality of liquid jets is about 120 micrometers. 6. The method set forth in claim 1 wherein the second spacing is between about 400 micrometers and about 1000 micrometers, and a diameter of an orifice of each liquid jet of the second plurality of liquid jets is between about 90 micrometers and about 150 micrometers. 7. The method set forth in claim 6 wherein the second spacing is between about 500 micrometers and about 700 micrometers. 8. The method set forth in claim 1 wherein the first plurality of liquid jets is produced by a first manifold and a second manifold spaced apart from each other along a direction of machine travel, the first manifold sprays at a first manifold pressure and the second manifold sprays at a second manifold pressure. 9. The method set forth in claim 8 wherein the first manifold pressure and the second manifold pressure are each between about 20 bars and about 120 bars. 10. The method set forth in claim 8 wherein the first manifold pressure is about 35 bars and the second manifold pressure is about 75 bars. 11. The method set forth in claim 1 wherein the second plurality of liquid jets each sprays at a third pressure. 12. The method set forth in claim 11 wherein the third pressure is between about 20 bars and about 120 bars. 13. The method set forth in claim 11 wherein the third pressure is between about 40 bars and about 90 bars. 14. The method set forth in claim 1 wherein the second plurality of liquid jets is produced by third, fourth and fifth manifolds spaced apart from each other along a direction of machine travel. 15. The method set forth in claim 1 wherein a total energy imparted by the first plurality of liquid jets and the second plurality of liquid jets is between about 0.1 kilowatt-hours per kilogram and about 0.9 kilowatt-hours per kilogram. 16. The method set forth in claim 1 wherein a total energy imparted by the first plurality of liquid jets and the second plurality of liquid jets is between about 0.2 kilowatt-hours per kilogram and about 0.5 kilowatt-hours per kilogram. 17. The method set forth in claim 1 wherein the consistency of the liquid suspension is between about 0.03 and about 0.05 percent fiber by weight. 18. The method set forth in claim 1 wherein drying the nonwoven tissue web comprises carrying the nonwoven tissue web on a through-drying fabric through a through-air dryer. 19. A method for making a dispersible nonwoven sheet, the method comprising: dispersing natural fibers and regenerated fibers in a ratio of about 70 to about 90 percent by weight natural fibers and about 10 to about 30 percent by weight regenerated fibers in a liquid medium to form a liquid suspension, wherein the consistency of the liquid suspension is between about 0.02 and about 0.08 percent fiber by weight;depositing the liquid suspension over a foraminous forming wire to form a nonwoven tissue web;spraying the nonwoven tissue web with a first plurality of liquid jets, each liquid jet of the first plurality of liquid jets being spaced from an adjacent one of the first plurality of liquid jets by a first distance, wherein a first region of the nonwoven tissue web is displaced by one of the first plurality of liquid jets, a second region of the nonwoven tissue web is displaced by an adjacent one of the first plurality of liquid jets, and the natural fibers and regenerated fibers in each of the first region and the second region are displaced in a direction along an axis perpendicular to the plane of the nonwoven tissue web, the natural and regenerated fibers displaced in the second region do not overlap with natural and regenerated fibers in the first region, the first plurality of liquid jets being produced by a first manifold and a second manifold spaced apart from each other along a direction of machine travel, the first manifold spraying at a first manifold pressure and the second manifold spraying at a second manifold pressure, each of the first manifold pressure and the second manifold pressure being between about 20 bars and about 120 bars;spraying the nonwoven tissue web with a second plurality of liquid jets, each liquid jet of the second plurality of liquid jets being spaced from an adjacent one of the second plurality of liquid jets by a second distance, wherein the second distance is less than the first distance, the second plurality of liquid gets substantially hydroentangles the natural and regenerated fibers in both the first and second regions of the natural and regenerated fibers, wherein a total energy imparted by the first plurality of liquid jets and the second plurality of liquid jets is between about 0.1 kilowatt-hours per kilogram and about 0.9 kilowatt-hours per kilogram; anddrying the nonwoven tissue web to form the dispersible nonwoven sheet. 20. The method set forth in claim 19 wherein the second plurality of liquid jets are produced by third, fourth and fifth manifolds spaced apart from each other along the direction of machine travel.