Absorbent cellulosic products with regenerated cellulose formed in-situ
View Patent ↗A method of making absorbent cellulosic sheet includes forming a web of papermaking fibers, extruding a cellulosic dope of underivatized cellulose, disposing the dope upon the web and regenerating the cellulose in-situ. Regenerated filaments may have a denier of from about 0.05 to about 20.
1. A method of making absorbent cellulosic sheet comprising:
(a) forming a web of papermaking fibers;
(b) extruding a cellulosic dope, the cellulosic dope comprising underivatized cellulose dissolved in a cellulose-dissolving solvent composition selected such that the cellulosic dope may be regenerated by contacting the dope with water;
(c) disposing the cellulose dope upon the web; and
(d) regenerating cellulose from the extruded dope in-situ, wherein the regenerated cellulose is in the form of discrete filaments capable of being hydro-entangled with the papermaking fibers.
2. The method according to claim 1 , wherein the solvent composition comprises a cellulose-dissolving tertiary amine oxide.
3. The method according to claim 2 , wherein the tertiary amine oxide is N-methylmorpholine-N-oxide (NMMO).
4. The method according to claim 1 , wherein the solvent composition comprises a cellulose-dissolving ionic liquid.
5. The method according to claim 4 , wherein the ionic liquid comprises an imidazolium salt.
6. The method according to claim 5 , wherein the imidazolium salt is a dialkylimidazolium chloride.
7. The method according to claim 1 , wherein the solvent composition comprises a non-solvent for the cellulose.
8. The method according to claim 1 , wherein the regenerated cellulose filaments are bonded with papermaking fibers in the web.
9. The method according to claim 8 , wherein the regenerated cellulose filaments are arranged in a sinuate pattern in the web.
10. The method according to claim 8 , wherein the regenerated cellulose filaments are arranged in a sinusoidal pattern in the web.
11. The method according to claim 8 , wherein the regenerated cellulose filaments form a network pattern in the web.
12. The method according to claim 9 , wherein the regenerated cellulose filaments form an x-pattern network in the web.
13. The method according to claim 1 , wherein the regenerated cellulose filaments form a circular network pattern in the web.
14. The method according to claim 1 , further comprising the step of hydroentangling the regenerated cellulose filaments with the web.
15. The method according to claim 1 , wherein cellulose is regenerated in the web by applying water to the web subsequent to applying the cellulose dope to the web.
16. The method according to claim 1 , wherein the cellulosic dope is extruded as discrete filaments which are pneumatically drawn prior to contacting the web.
17. The method according to claim 1 , wherein the discrete filaments of regenerated cellulose have a denier of from about 0.05 to about 20 g/9000 meters.
18. The method according to claim 1 , wherein the discrete filaments of regenerated cellulose have a denier of from about 0.1 to about 10 g/9000 meters.
19. The method according to claim 1 , wherein the regenerated cellulosic filaments are arranged in a sinuate pattern upon the web.
20. The method according to claim 1 , wherein the regenerated cellulosic filaments form a network pattern upon the web.