Process for obtaining low residual aramid materials

Patent metadata

Field	Value
Publication number	US-9580863-B2
Application number	US-201314396390-A
Country	US
Kind code	B2
Filing date	May 1, 2013
Priority date	May 3, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

The present invention provides for a process for reducing the content of one or more residuals in aramid fibers or filaments, comprising, in this order, the steps of introducing the aramid fiber or filaments into a extraction solution adjusted to a pH ranging from of 2 to 7, adjusting the extraction solution and the aramid fibers or filaments to a temperature of to from 80° C. to 140° C., removing the aramid fibers or filaments from the extraction solution, introducing the aramid fiber or filaments into a first rinsing solution adjusted to a pH ranging from of 2 to 7, optionally comprising a detergent, adjusting the first rinsing solution and the aramid fibers and filaments to a temperature of from 70° C. to 100° C., removing the aramid fibers or filaments from the first rinsing solution.

First claim

What is claimed is:

1. A process for reducing the content of one or more residuals in aramid fibers or filaments, comprising, in this order, the steps of
a. introducing the aramid fibers or filaments into a extraction solution being free of any coloring ingredient and adjusted to a pH ranging of from 2 to 7,
b. adjusting the extraction solution and the aramid fibers or filaments to a temperature of from 80° C. to 140° C.
c. removing the aramid fibers or filaments from the extraction solution
d. introducing the aramid fibers or filaments into a first rinsing solution adjusted to a pH ranging of from 2 to 7,
e. optionally comprising a detergent,
f. adjusting the first rinsing solution and the aramid fibers or filaments to a temperature of from 70° C. to 100° C.,
g. removing the aramid fibers or filaments from the first rinsing solution,
wherein the extraction solution is an aqueous solution comprising of from 0 to 40 g/l of a salt component and of from 0 to 40 g/l of a carrier component, and
wherein the sum of the salt and carrier components is of from 20 g/l to 80 g/l;

wherein the process provides aramid fibers or filaments having 0.01 to 0.2 weight percent orthodichlorobenzene; N-methyl-2-pyrrolidone(NMP); 1,3-Dimethyl-2-Imidazolidinone(DMI); or N,N-dimethylacetamide (DMAC).

2. The process according to claim 1 , further comprising the steps of
h. introducing the aramid fibers or filaments into a second rinsing solution adjusted to a pH ranging from of 2 to 7, optionally comprising a detergent,
i. adjusting the second rinsing solution and the aramid fibers or filaments to a temperature of from 10° C. to 70° C.,
j. removing the aramid fibers or filaments from the second rinsing solution.

3. The process according to claim 1 , wherein a liquor ratio of aramid fibers or filaments to extraction solution is of from 1:1 to 1:180.

4. The process according to claim 1 , wherein the extraction solution comprises the salt component in an amount ranging of from 0 to 20 g/l and the carrier component in an amount ranging of from 20 to 40 g/l, when the liquor ratio is between 1:1 and 1:20, provided that the sum of the salt and carrier components is of from 20 g/l to 60 g/l.

5. The process according to claim 1 , wherein the extraction solution comprises the salt component in an amount ranging of from 20 to 40 g/l and the carrier component in an amount ranging of from 0 to 25 g/l when the liquor ratio is between 1:20 and 1:180; provided that the sum of the salt and carrier components is of from 20 g/l to 65 g/l.

6. The process according to claim 1 , wherein the extraction solution is adjusted to a pH ranging from of 3 to 5.

7. The process according to claim 1 , wherein the aramid fibers or filaments are meta-aramid fibers or filaments.

8. A meta-aramid fiber or filament obtained by the process of claim 7 , wherein it comprises less than 0.1 weight percent of orthodichlorobenzene, and wherein the meta-aramid fiber or filament is a dried, crystalline meta-aramid fiber or filament obtained by dryspinning.

9. A yarn comprising the meta-aramid fiber or filament of claim 8 , and at least one anti-static fiber.

10. A heat, flame and arc resistant garment comprising the aramid fiber or filament according to claim 8 .

11. A heat, flame and arc resistant fabric comprising the aramid fiber or filament according to claim 8 .

12. A meta-aramid fiber or filament obtained by the process of claim 7 , wherein it comprises less than 0.1 weight percent of N-methyl-2-pyrrolidone or N,N- dimethylacetamide, and wherein the meta-aramid fiber or filament is a dried, crystalline meta-aramid fiber or filament obtained by dry-spinning.

Assignees

• Du Pont

Inventors

• Bader Yves
• Wyss Kurt Hans
• De Cuendias Herrero Bienvenido

Classifications

• D06M13/188 Primary

  Monocarboxylic acids; Anhydrides, halides or salts thereof {(D06M13/1845 takes precedence)} · CPC title

• D01F6/605

  from aromatic polyamides · CPC title

• D06M11/65

  Salts of oxyacids of nitrogen · CPC title

• D01F13/04

  of synthetic polymers · CPC title

• D06M15/59 Primary

  Polyamides; Polyimides · CPC title