Process for pretreating reclaimed cotton fibers to be used in the production of molded bodies from regenerated cellulose

Patent metadata

Field	Value
Publication number	US-10316467-B2
Application number	US-201415027945-A
Country	US
Kind code	B2
Filing date	Nov 18, 2014
Priority date	Nov 26, 2013
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A process for pretreating reclaimed cotton fibers to be used in the production of molded bodies from regenerated cellulose, characterized by effective metal reduction and adjustment of the degree of polymerization and brightness, including a metal removing stage and an oxidative bleaching stage of the reclaimed cotton fibers or pulp produced thereof. Reclaimed cotton fibers treated according to the described process may be used alone or in blends with conventional dissolving pulp as raw material for the production of molded bodies from regenerated cellulose. The process enables technically smooth, safe, and economically feasible spinning via the Viscose or Lyocell process, therefore, the current invention provides an efficient recycling pathway for cotton waste materials.

First claim

What is claimed is:

1. A process for obtaining a molded cellulose body comprising:
pretreating reclaimed cotton fibers in a chemical metal removing stage and an oxidative bleaching stage;
preparing a spinning dope comprising the reclaimed cotton fibers by a lyocell or viscose process to produce a regenerated cellulose; and
obtaining the molded cellulose body.

2. The process according to claim 1 , wherein the cotton fibers are reclaimed from pre-consumer cotton waste.

3. The process according to claim 1 , wherein the cotton fibers are reclaimed from post-consumer cotton waste.

4. The process according to claim 1 , wherein the reclaimed cotton fibers include pulp prepared from cotton rags.

5. The process according to claim 1 , wherein the reclaimed cotton fibers are mechanically shredded, milled, or opened prior to their use.

6. The process according to claim 1 , wherein the chemical metal removing stage is an acidic washing treatment and/or a treatment with a complexing agent.

7. The process according to claim 6 , wherein the reclaimed cotton fibers are treated by an aqueous solution of a complexing agent.

8. The process according to claim 6 , wherein both treatments are combined in one step by adding a complexing agent to the acidic washing treatment.

9. The process according to claim 1 , wherein the oxidative bleaching stage comprises an oxygen bleaching treatment.

10. The process according to claim 1 , wherein the oxidative bleaching stage comprises a peroxide bleaching treatment.

11. The process according to claim 1 , wherein the oxidative bleaching stage comprises an ozone bleaching treatment.

12. The process according to claim 1 , wherein the oxidative bleaching stage comprises a sequence of oxidative bleaching treatments selected from the group consisting of oxygen bleaching treatment, peroxide bleaching treatment and ozone bleaching treatment.

13. The process according to claim 1 , wherein the molded cellulose body is produced according to the Viscose process.

14. The process according to claim 13 , wherein the process conditions are chosen such that an intrinsic viscosity of the reclaimed cotton fibers after pretreating is in the range between 850 to 300 ml/g.

15. The process according to claim 14 , wherein the intrinsic is in the range between 650 to 350 ml/g.

16. The process according to claim 15 , wherein the intrinsic viscosity is in the range between 550 to 400 ml/g.

17. The process according to claim 13 , wherein the molded body is a staple fiber, filament fiber, sponge or foil of the Viscose or Modal type.

18. The process according to claim 13 , wherein the viscose process is a Modal process.

19. The process according to claim 1 wherein the molded cellulose body is produced according to the Lyocell process.

20. The process according to claim 19 , wherein the process conditions are chosen such that an intrinsic viscosity of the reclaimed cotton fibers after pretreating is in the range between 650 to 300 ml/g.

21. The process according to claim 20 , wherein the intrinsic viscosity is in the range between 500 to 350 ml/g.

22. The process according to claim 21 , wherein the intrinsic viscosity is in the range between 440 to 360 ml/g.

23. The process according to claim 19 , wherein the molded body is a staple fiber, filament fiber, sponge or foil of the Lyocell type.

24. The process according to claim 1 , wherein the spinning dope further comprises dissolving pulp.

25. The process according to claim 1 , wherein the resulting molded bodies are used for further processing into textile or nonwoven products.

26. The process according to claim 1 , wherein the spinning dope comprises 100% reclaimed cotton fibers.

Assignees

• Chemiefaser Lenzing Ag

Inventors

• Weilach Christian
• Möderl Susanne
• Sperger Christian
• Borgards Andrea

Classifications

• C08B16/00

  Regeneration of cellulose · CPC title

• D21C9/163

  with peroxides · CPC title

• D01G11/00

  Disintegrating fibre-containing articles to obtain fibres for re-use · CPC title

• D01F2/06 Primary

  from viscose · CPC title

• Y02W30/66

  Disintegrating fibre-containing textile articles to obtain fibres for re-use · CPC title