Cellulose filament process

Patent metadata

Field	Value
Publication number	US-11414786-B2
Application number	US-201816753583-A
Country	US
Kind code	B2
Filing date	Oct 8, 2018
Priority date	Oct 6, 2017
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

The present invention provides a process for the viable production of lyocell cellulose continuous filament yarns.

First claim

The invention claimed is:

1. A process for the production of lyocell type cellulose filament yarns from a lyocell spinning solution of cellulose in an aqueous tertiary amine oxide comprising the following steps:
manufacturing a spinning solution containing 10 to 20 wt.-% cellulose, wherein the cellulose is a blend of 5-30 wt.-% of a cellulose having a scan viscosity in the range of 450-700 ml/g with 70-95 wt.-% of cellulose having a scan viscosity in the range of 300-450 ml/g, wherein the two fractions do show a difference in scan viscosity of at least 40 ml/g;
extruding the spinning solution through extrusion nozzles to obtain filaments;
guiding the filaments through an air gap having a length in the range of from 40 to 130 mm;
coagulating the filaments via a spin bath containing a coagulation liquor with a concentration of tertiary amine oxide of 20% or less, wherein the spin bath has a depth of from 5 to 30 mm;
washing the filaments; and
drying the filaments.

2. The process according to claim 1 , wherein a multifilament yarn is produced.

3. The process according to claim 1 , wherein the filaments after exiting the nozzles are contacted with a cross draught air-flow of 0.5-3 m/sec.

4. The process according claim 1 , wherein the air gap is provided between an exit of the nozzles and a surface of the spin bath.

5. The process according to claim 1 , wherein the filaments are taken up by a guidance roller after exiting the spin bath.

6. The process according to claim 4 , wherein a maximum tension applied to a filament bundle at a contact point of the filament bundle with a guidance roller is (4.2 ×filament number/filament titer)0.69 (cN) or less.

7. The process according to claim 1 , wherein in the drying is carried out at a constant filament tension below 10cN per 80 dtex.

8. The process according to claim 1 , wherein a temperature variability through the extrusion nozzles is controlled to ±2° C. or less.

9. The process according to claim 1 , further comprising the washing of yarns.

10. The process according to claim 1 , wherein the spinning solution is subjected to a filtration step prior to filament formation.

11. The process according to claim 1 , wherein the spin bath has a concentration of the tertiary amine oxide of from 8 to 20 wt.-%.

12. A filament or multifilament yarn, obtained by the process of claim 1 .

13. The process according to claim 9 , wherein the washing of yarns is via a series of modular devices which enable uniform application and removal of washing liquor.

14. The process according to claim 10 , wherein the spinning solution is subjected to the filtration step prior to filament formation using a multi-stage depth filtration with an absolute stopping power below 20 microns.

15. The process according to claim 10 , wherein a multi-stage depth filtration has an absolute stopping power less than 15 microns.

16. The process according to claim 1 , wherein the air gap is provided between an exit of the nozzles and a surface of the spin bath, having a length in the range of from 50 to 100 mm.

17. The process according to claim 1 , wherein the spin bath has a depth of from 10 to 20 mm.

18. The process according to claim 1 , wherein the spinning solution has a temperature of from 105 to 120° C.

19. The process according to claim 1 , wherein a cross draught of air having a velocity of 0.5 to 3 m/sec is provided in the air gap.

20. The process according to claim 19 , wherein the cross draught is air having a moisture content in the range of from 0.5 to 10 g water per kg air.

Assignees

• Chemiefaser Lenzing Ag

Inventors

• Schrempf Christoph
• Gressenbauer Andreas
• Gugerell Franz
• Neunteufel Martin
• Reiter Ernst

Classifications

• B29C48/919

  using a bath, e.g. extruding into an open bath to coagulate or cool the material · CPC title

• B29C48/05

  Filamentary, e.g. strands · CPC title

• D01D1/02 Primary

  Preparation of spinning solutions · CPC title

• D01F2/00 Primary

  Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof · CPC title

• B29C48/274

  of the extruded articles · CPC title