High strength and low stiffness hesperaloe tissue
Soft, durable and bulky tissue products comprising non-wood fibers and more particularly high yield hesperaloe pulp fibers are disclosed. The tissue products preferably comprise at least about 5 percent, by weight of the product, high yield hesperaloe pulp fiber and have relatively modest tensile strengths, such as a geometric mean tensile (GMT) greater than about 1,000 g/3″, and improved durability and cross-machine direction (CD) properties, such as a CD Stretch greater than about 10 percent. Additionally, at the foregoing tensile strengths the products are not overly stiff. For example the tissue products may have a Stiffness Index less than about 10.0.
1. A tissue product comprising from about 5 to about 50 percent, by weight of the product, high yield hesperaloe fibers, the tissue product having a geometric mean tensile (GMT) greater than about 1,000 g/3″, a CD stretch greater than about 10 percent, a Durability Index greater than about 38.0 and Stiffness Index less than about 7.0.
2. The tissue product of claim 1 having a slough less than about 8.0 mg.
3. The tissue product of claim 1 having a dry burst strength greater than about 800 gf.
4. The tissue product of claim 1 having a CD TEA greater than about 5.0 g·cm/cm2.
5. The tissue product of claim 1 having a CD tensile strength greater than about 500 g/3″.
6. The tissue product of claim 1 having a GM Tear strength greater than about 15 gf.
7. The tissue product of claim 1 having a basis weight from about 30 to about 60 grams per square meter (gsm) and a sheet bulk greater than about 10 cc/g.
8. The tissue product of claim 1 comprising from about 20 to about 50 percent, by weight of the product, high yield hesperaloe fibers.
9. The tissue product of claim 1 having a GM Slope of less than about 6.0 kg.
10. The tissue product of claim 1 having a GMT from about 1,000 to about 1,500 g/3″ and Stiffness Index from about 4.0 to about 7.0.
11. A tissue product comprising at least one multi-layered through-air dried tissue web comprising a first and a second layer, the first layer being substantially free from high yield hesperaloe pulp fibers and the second layer consisting essentially of high yield hesperaloe pulp fibers, the tissue product having a geometric mean tensile (GMT) greater than 1,000 g/3″, a Durability Index greater than about 28.0 and a Stiffness Index less than about 10.0, wherein the tissue product comprises from about 20 to about 50 weight percent high yield hesperaloe pulp fibers.
12. The tissue product of claim 11 having a Burst Index greater than about 8.0 and a TEA Index greater than about 8.0.
13. The tissue product of claim 11 having a GM Slope less than about 6.0 kg and a Stiffness Index from about 4.0 to about 7.0.
14. The tissue product of claim 11 having a basis weight from about 30 to about 60 gsm and a sheet bulk from about 10 to about 15 cc/g.
15. The tissue product of claim 11 wherein the tissue product is substantially free from softwood kraft pulp fibers.
16. A method of forming a resilient high bulk tissue product comprising the steps of:
(a) dispersing high yield hesperaloe fiber in water to form a first fiber slurry; (b) dispersing conventional wood pulp fibers in water to form a second fiber slurry; (c) depositing the first and the second fiber slurries in a layered arrangement on a moving belt to form a tissue web, wherein the web comprises from about 5 to about 50 percent, by weight of the web, high yield hesperaloe fibers; (d) non-compressively drying the tissue web to yield a dried tissue web having a consistency from about 80 to about 99 percent solids; and (e) calendering the dried tissue web to yield a finished tissue product having a geometric mean tensile (GMT) greater than about 1,000 g/3″, a CD stretch greater than about 10 percent, a Durability Index greater than about 38.0 and Stiffness Index less than about 7.0.
17. The method of claim 16 wherein the resulting tissue product has a basis weight from about 20 to about 60 gsm, a sheet bulk greater than about 12 cc/g and a slough less than about 8.0 mg.
18. The method of claim 16 wherein the tissue product comprises from about 5 to about 50 percent high yield hesperaloe fiber and less than about 10 percent, by weight of the tissue product, Northern softwood kraft (NSWK).
19. The method of claim 16 wherein the step of calendering comprises passing the web through a nip having a load of at least about 40 pli, wherein the step of calendering reduces the sheet bulk by less than about 50 percent.
20. The method of claim 16 wherein the dried tissue web has a sheet bulk greater than about 15 cc/g and the finished tissue product has a sheet bulk greater than about 12 cc/g.