Method for producing regenerated cellulosic fibers

Patent metadata

Field	Value
Publication number	US-2025084566-A1
Application number	US-202218292781-A
Country	US
Kind code	A1
Filing date	Jul 22, 2022
Priority date	Jul 26, 2021
Publication date	Mar 13, 2025
Grant date	—

Abstract

A method and a production facility for producing regenerated cellulosic fibers. A spinning solution is extruded into a coagulation bath which contains a salt and preferably an alkali. The spinning solution comprises cellulose dissolved in an aqueous solvent comprising NaOH and ZnO and the coagulation bath has a pH-value of at least seven. The fibers in the fiber tow are fixated and stretched to essentially their final cellulose specific diameter before being cut to staple fibers in an undried state.

First claim

1 . A method for producing regenerated cellulosic fibers comprising extruding a spinning solution into a coagulation bath which contains a salt and preferably an alkali to produce a fiber tow, the spinning solution comprising cellulose dissolved in an aqueous solvent comprising NaOH and ZnO, the coagulation bath having a pH-value of at least seven, the method comprising the steps of:
stretching the fibers in the fiber tow to a final cellulose specific diameter before being cut to staple fibers in an undried state; and orienting the fibers in the fiber tow to a final state before being cut to staple fibers in an undried state.

2 . The method according to claim 1 , further comprising the steps of:
routing the fiber tow into at least one conditioning bath, the conditioning bath comprising between about 10 percent to about 30 percent per weight a salt to facilitate a further coagulation of the spinning solution, the conditioning bath preferably being fluidly separated from a downstream washing line, and stretching the fibers in the fiber tow to the final cellulose specific diameter and orienting the fibers in the fiber tow to the final state in the at least one conditioning bath.

3 . The method according to claim 2 , wherein the coagulation bath and the conditioning bath are fluidly connected, wherein a temperature of the coagulation bath and a temperature of the conditioning bath are independently controlled.

4 . The method according to claim 1 , further comprising the steps of:
routing the fiber tow through a washing line, the washing line comprising at least one washing step, wherein the washing line is preferable arranged downstream of at least one conditioning bath; and keeping a tension of the fiber tow and a cellulose specific diameter of the fibers constant in the washing line.

5 . The method according to claim 1 , further comprising the steps of:
suspending the cut fibers and collecting the cut fibers in a non-woven fiber layer, pressing the non-woven fiber layer to impose a natural crimp on the fibers.

6 . The method according to claim 1 , further comprising at least one of the following steps:
collecting the cut fibers into a non-woven fiber layer and washing the non-woven fiber layer; neutralizing the cut or uncut fibers with an acidic liquid, wherein the acidic liquid is one of diluted acetic acid, lactic acid, and sulphuric acid; bleaching the cut or uncut fibers; applying a crosslinking agent to the cut or uncut fibers; applying a finishing agent to the cut or uncut fibers; drying the fibers; pressing the fiber tow and/or the non-woven fiber layer before and/or after any other processing step.

7 . The method according to claim 1 , further comprising at least one of opening the non-woven fiber layer to loosen up and/or at least partially separate the fibers.

8 . A processing facility for producing regenerated cellulosic fibers including a spinneret for extruding a spinning solution into a coagulation bath which contains a salt and preferably an alkali to produce a fiber tow, the spinning solution comprising cellulose dissolved in an aqueous solvent comprising NaOH and ZnO, the coagulation bath having a pH-value of at least seven, the processing facility comprising:
at least one stretching device configured to stretch the fibers in the fiber tow to a final cellulose specific diameter and orient cellulose in the fibers to a final state; and a cutter for cutting the fibers to staple fibers in an undried state.

9 . The processing facility according to claim 8 , further comprising:
at least one conditioning bath downstream of the coagulation bath, the conditioning bath comprising between about 10 percent to about 30 percent per weight a salt that facilitates a further coagulation of the spinning solution, the conditioning bath preferably being fluidly separated from a downstream washing line; and at least one stretching device configured to stretch the fibers in the fiber tow to the final cellulose specific diameter and orienting the cellulose in the fibers to the final state within the at least one conditioning bath.

10 . The processing facility according to claim 9 , wherein the coagulation bath and the conditioning bath are fluidly connected and wherein a temperature of the coagulation bath and a temperature of the conditioning bath are independently controlled.

11 . The processing facility according to claim 8 , further comprising a washing line through which the fiber tow is routed, the washing line comprising at least one washing step and being configured downstream of at least one conditioning bath, and wherein a tension of the fiber tow and a cellulose specific diameter of the fibers are kept constant in the washing line.

12 . The processing facility according to claim 8 , further comprising:
a fleece-forming device configured to suspend the cut fibers and collect the cut fibers in a non-woven fiber layer; and at least one pressing device configured to press the non-woven fiber layer to impose a natural crimp on the cut fibers.

13 . The processing facility according to claim 8 , further comprising at least one treatment facility comprising at least one of:
at least one washing device configured to wash the fiber tow or the non-woven fiber layer; at least one further pressing device configured to press the fiber tow or the non-woven fiber layer; a neutralizer configured to neutralize the cut or uncut fibers with an acidic liquid; a bleaching facility configured to bleach the cut or uncut fibers; a crosslinking facility configured to apply a crosslinking agent to the cut or uncut fibers; a finishing facility configured to apply a finishing agent to the cut or uncut fibers; an opener configured to open the non-woven fiber layer to loosen up and/or at least partially separate the cut fibers; and a dryer configured to dry the fibers.

14 . A regenerated cellulosic fiber, produced in a processing facility for producing regenerated cellulosic fibers including a spinneret for extruding a spinning solution into a coagulation bath which contains a salt and preferably an alkali to produce a fiber tow, the spinning solution comprising cellulose dissolved in an aqueous solvent comprising NaOH and ZnO, the coagulation bath having a pH-value of at least seven, the processing facility further comprising at least one stretching device configured to stretch the fibers in the fiber tow to a final cellulose specific diameter and orient cellulose in the fibers to a final state; and a cutter for cutting the fibers to staple fibers in an undried state.

15 . A product comprising a regenerated cellulosic fiber a processing facility for producing regenerated cellulosic fibers including a spinneret for extruding a spinning solution into a coagulation bath which contains a salt and preferably an alkali to produce a fiber tow, the spinning solution comprising cellulose dissolved in an aqueous solvent comprising NaOH and ZnO, the coagulation bath having a pH-value of at least seven, th processing facility further comprising at least one stretching device configured to stretch the fibers in the fiber tow to a final cellulose specific and orient cellulose in the fibers to a final state, and a cutter for cutting the fibers to staple fibers in an undried state.

16 . The product according to claim 15 , wherein the product is selected from a list consisting of: yarns, fabrics, textiles, home textiles, garments, nonwovens, hygiene products, upholstery, or technical applications.

17 . A regenerated cellulosic fiber, produced by a method for producing

Assignees

• Chemiefaser Lenzing Ag

Inventors

• Röder Thomas
• Suchomel Friedrich
• Mayrhofer-Huber Christian
• Duchlbauer Makus

Classifications

• D01D13/00

  Complete machines for producing artificial threads · CPC title

• D01D10/06

  Washing or drying · CPC title

• D01D5/26

  Formation of staple fibres (by flash-spinning D01D5/11) · CPC title

• D01D5/06

  Wet spinning methods {(D01D5/0046 takes precedence)} · CPC title

• D01D1/02

  Preparation of spinning solutions · CPC title