Modified linkbelt molding and throughdrying fabrics

Abstract

Throughdried tissue sheets can be made using a linkbelt throughdrying fabric and/or transfer fabric. In particular, linkbelts can be modified with topically-applied materials, such as extruded or printed silicone materials, in a pattern that provides an overall background texture and/or a decorative design that is imparted to the resulting tissue.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a plan view photograph of a modified linkbelt in accordance with this invention having decorative design elements, namely puppies and butterflies. The base linkbelt is a Voith Fabrics Finelink BC.

FIG. 2 is a plan view photograph of a modified linkbelt in accordance with this invention having a decorative design formed by geometric design elements comprising intersecting circles (wedding ring pattern). The base linkbelt is a Voith Fabrics Finelink BC.

FIG. 3 is a plan view photograph of a modified linkbelt in accordance with this invention having a textured background surface formed by a series of wavy ripples. The base linkbelt is a Voith Fabrics Finelink BC.

FIG. 4 is a plan view photograph of a modified linkbelt in accordance with this invention having both decorative design elements and textured background surface elements, namely a printed “Scott” logo decorative design element surrounded by a relatively flat unprinted highlight area within a printed textured background surface comprising a series of closely-spaced four-dot elements. The base linkbelt is a Voith Fabrics Finelink BC.

FIG. 5 is plan view photograph of a tissue sheet made using the modified linkbelt of FIG. 2.

FIG. 6 is a plan view photograph of a tissue sheet made using the modified linkbelt of FIG. 3.

FIG. 7 is a plan view photograph of a tissue sheet made using the modified linkbelt of FIG. 4.

EXAMPLES

Example 1

In order to further illustrate this invention, a three-layered tissue sheet suitable for single-ply bath tissue was made in which the two outer layers comprised a debonded mixture of Aracruz eucalyptus fibers and broke fibers and the center layer comprised refined northern softwood kraft (NSWK) fibers. Broke fibers comprised 16.5 percent of the sheet on a dry fiber basis. Prior to formation, the outer layer fibers were pulped for 15 minutes at 10 percent consistency and diluted to about 2.5 percent consistency after pulping. A debonder (ProSoft TQ1003) was added to the outer layer pulp in the amount of 1 kilogram of debonder per tonne of outer layer dry fiber. The NSWK fibers were pulped for 30 minutes at 4 percent consistency and diluted to about 2.7 percent consistency after pulping. The overall layered sheet weight was split 34 percent to the center layer on a dry fiber basis and 33 percent to each of the outer layers. The center layer was refined to levels required to achieve target strength values, while the outer layers provided surface softness and bulk. Parez 631NC was added to the center layer at 1.5 kilograms per tonne of center layer dry fiber.

A three-layer headbox was used to form the wet web with the refined NSWK stock in the center layer of the headbox. Turbulence-generating inserts recessed about 3.5 inches (89 millimeters) from the slice and layer dividers extending about 1 inch (25 millimeters) beyond the slice were employed. The net slice opening was about 0.9 inch (23 millimeters). The water flows in the headbox layers were split 28.5 percent to each of the outer layers and 43 percent to the center layer. The consistency of the stock fed to the headbox was about 0.1 weight percent.

The resulting three-layered web was formed on a twin-wire, suction form roll former, with the outer forming fabric being an Asten 867A, and the inner forming fabric being a Voith Fabrics 2164-33B. The speed of the forming fabrics was 2000 feet per minute (10.16 meters per second). The newly-formed web was then dewatered to a consistency of about 27-29 percent using vacuum suction from below the forming fabric before being transferred to a transfer fabric, which was traveling at 1600 feet per minute (8.13 meters per second) (25 percent rush transfer). The transfer fabric was a Voith Fabrics t1207-6. A vacuum shoe pulling about 10 inches (254 mm) of mercury rush transfer vacuum was used to transfer the web to the transfer fabric.

The web was then transferred to a Voith Fabrics Finelink BC linkbelt throughdrying fabric modified with a printed pattern as shown in FIG. 3. The air permeability of the modified linkbelt was about 150 m³/min/m².

A vacuum transfer roll was used to wet mold the sheet into the throughdrying fabric at about 8 inches (203 mm) of mercury wet molding vacuum. The throughdrying fabric was traveling at a speed of about 8.13 meters per second. The web was carried over a pair of Honeycomb throughdryers operating at a supply temperature of about 390° F. (199° C.) and dried to final dryness of about 99 percent consistency.

The resulting tissue is shown in FIG. 6. It had a basis weight of 31.0 gsm, a geometric mean tensile strength of 704 grams per 7.62 centimeters of width, a ratio of the machine direction tensile strength to the cross-machine direction tensile strength of 1.72, and a caliper of 840 microns.

Example 2

Tissue sheets were made as described in Example 1, except that the speed of the forming fabrics was 2048 feet per minute (10.40 meters per second, 28% rush transfer) and the throughdrying fabric was a Voith Fabrics Finelink BC linkbelt modified with a printed pattern as shown in FIG. 4. The air permeability of the modified linkbelt was about 160 m³/min/m².

The resulting tissue is shown in FIG. 7. It had a basis weight of 31.2 gsm, a geometric mean tensile strength of 936 grams per 7.62 centimeters of width, a ratio of the machine direction tensile strength to the cross-machine direction tensile strength of 1.83 and a caliper of 853 microns.

Example 3

Tissue sheets were made as described in Example 2, except that the throughdrying fabric was a Voith Fabrics Finelink BC linkbelt modified with a printed pattern as shown in FIG. 2. The air permeability of the modified linkbelt was about 220 m³/min/m².

The resulting tissue is shown in FIG. 5. It had a basis weight of 31.1 gsm, a geometric mean tensile strength of 830 grams per 7.62 centimeters of width, a ratio of the machine direction tensile strength to the cross-machine direction tensile strength of 1.75, and a caliper of 644 microns.

It will be appreciated that the foregoing examples, given for purposes of illustration, are not to be construed as limiting the scope of this invention, which is defined by the following claims and all equivalents thereto.

Claims

1. A modified linkbelt.

2. The linkbelt of claim 1 having a topically-applied material in the form of a decorative design.

3. The linkbelt of claim 1 having a topically-applied material in the form of a textured background surface.

4. The linkbelt of claim 1 having a topically-applied material in the form of a textured background surface and a decorative design.

5. The linkbelt of claim 4 wherein the decorative design is surrounded by an unprinted highlight area.

6. The linkbelt of claim 1 or 2 or 3 wherein the surface area coverage of topically-applied material is from about 1 to about 80 percent.

7. The linkbelt of claim 1 or 2 or 3 wherein the surface area coverage of topically-applied material is from about 5 to about 50 percent.

8. The linkbelt of claim 1 or 2 or 3 having an air permeability of from about 100 to about 340 m3/min/m2.

9. The linkbelt of claim 1 or 2 or 3 having an air permeability of from about 150 to about 340 m3/min/m2.

10. The linkbelt of claim 1 or 2 or 3 wherein the topically-applied material is selected from the group consisting of silicones, polyesters, polyurethanes, epoxies, polyphenylsulfides, and polyetherketones.

11. A method of making a tissue sheet comprising depositing an aqueous suspension of papermaking fibers onto a forming fabric to form a wet web having a consistency of from about 20 to about 40 percent, transferring the wet web to a linkbelt and throughdrying the web to produce a tissue sheet.

12. The method of claim 11 wherein the wet web is transferred directly to a linkbelt throughdrying fabric.

13. The method of claim 11 wherein the wet web is transferred to a linkbelt transfer fabric and thereafter transferred to a linkbelt throughdrying fabric.

14. The method of claim 11 wherein the wet web is transferred to a linkbelt transfer fabric and thereafter transferred to a modified linkbelt throughdrying fabric.

15. The method of claim 11 wherein the wet web is transferred to a modified linkbelt transfer fabric and thereafter transferred to a linkbelt throughdrying fabric.

16. The method of claim 11 wherein the wet web is transferred to a conventional woven transfer fabric and thereafter transferred to a linkbelt throughdrying fabric.

17. A method of making a tissue sheet comprising depositing an aqueous suspension of papermaking fibers onto a forming fabric to form a wet web having a consistency of from about 20 to about 40 percent, transferring the wet web to a modified linkbelt and throughdrying the web to produce a tissue sheet.

18. The method of claim 17 wherein the wet web is transferred to a modified linkbelt transfer fabric.

19. The method of claim 17 wherein the wet web is transferred to a modified linkbelt transfer fabric and thereafter transferred to a modified linkbelt throughdrying fabric.

20. The method of claim 17 wherein the wet web is transferred to a conventional woven transfer fabric and thereafter transferred to a modified linkbelt throughdrying fabric.

21. The method of claim 11 or 17 wherein the consistency of the wet web is from about 20 to about 30 percent.

22. The method of claim 11 or 17 wherein the throughdried web is creped.

23. The method of claim 11 or 17 wherein the throughdried web is uncreped.

24. The method of claim 12, 13, 14, 15, 16, 19 or 20 wherein the speed of the throughdrying fabric is from about 10 to about 80 percent slower than the speed of the forming fabric.

25. The method of claim 13, 14, 15, 16, 18, 19 or 20 wherein the speed of the transfer fabric is from about 10 to about 80 percent slower than the speed of the forming fabric.