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Method for removing sulfur from fiber using an aqueous acid

An aqueous acid, fiber technology, applied in the field of using aqueous acid to remove sulfur from fibers

Active Publication Date: 2014-09-10
DUPONT SAFETY & CONSTR INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it has been found that spinning copolymers into high tenacity fibers has unique challenges not present in the PPD-T structure and requires new technologies

Method used

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  • Method for removing sulfur from fiber using an aqueous acid
  • Method for removing sulfur from fiber using an aqueous acid
  • Method for removing sulfur from fiber using an aqueous acid

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0079] The FM130D Littleford reactor was loaded with calcium chloride (CaCl 2 ) of N-methyl-2-pyrrolidone (NMP) solvent. Appropriate amounts of monomers 5(6)-amino-2-(p-aminophenyl)benzimidazole (DAPBI) and terephthaloyl dichloride (TCL) were then added to the reactor and reacted to form oligomers. To this mixture, appropriate amounts of p-phenylenediamine (PPD) and TCL were added to form the final copolymer crumb. The crumbs were milled into smaller particles and then washed first with sodium hydroxide solution to neutralize reaction by-products and then with water to remove NMP. The polymer was then recovered, dried and its measured intrinsic viscosity is summarized in Table 1.

[0080] Table 1

[0081] project

[0082] P1-3

example 2

[0084] The FM130D Littleford reactor was loaded with calcium chloride (CaCl 2 ) of N-methyl-2-pyrrolidone (NMP) solvent. Then, an appropriate amount of monomer 5(6)-amino-2-(p-aminophenyl 1 benzimidazole (DAPBI), PPD, and part of terephthaloyl dichloride (TCL) was added to the reactor and reacted to form Oligomers. To this mixture, an appropriate amount of TCL is added to form the final copolymer crumb. The crumb is ground into smaller particles and then first washed with sodium hydroxide solution to neutralize the reaction by-products, then water Washing to remove NMP.The polymer was then recovered, dried and its measured intrinsic viscosity is summarized in Table 2.

[0085] Table 2

[0086] project

DAPBI / PPD molar ratio

Intrinsic viscosity (dl / g)

P2-1

40 / 60

7.00

P2-2

50 / 50

6.39

P2-3

75 / 25

3.98

[0087] fiber example

[0088] In the following examples, solution spinning of the copolymer in concentr...

example 2 and comparative example C

[0106] A concentrated sulfuric acid solution of the polymer at a solids concentration of 22% by weight was formed using a neutralized copolymer made of TCL and DAPBI / PPD with a diamine molar ratio of 70 / 30. The copolymer solution was spun through a spinneret having 270 holes to produce a nominal linear density of 1.75 denier / filament. The yarn was coagulated and washed to 3.00% by weight sulfur.

[0107] The yarn was then washed continuously at 24 m / min in 9 wash cabinets. The second box used the HCl wash solution as given in Table 6, all other boxes used water. The first wash box uses 10 advancing yarn coils through the wash spray and applicator, however, the remaining 8 wash boxes use 20 advancing yarn coils through the wash spray and applicator. All wash modules were operated at 60°C. The yarn was dried in-line under a temperature ramp of 130°C to 205°C along the length of the oven at a tension of 0.5 g / denier. The yarn was then heat treated using a maximum temperature ...

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PUM

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Abstract

The present invention concerns methods for removing sulfur from a fiber made from a polymer comprising imidazole groups, said method comprising: contacting never-dried sulfate anion-containing polymeric-fiber with an aqueous acid having a pKa of less than 5 to displace at least a portion of the sulfate anions; and b) rinsing the fiber to remove the displaced sulfate ions.

Description

technical field [0001] This patent application relates to a method for removing sulfur from fibers made of polymers comprising imidazole groups. Background technique [0002] Advances in polymer chemistry and technology over the past few decades have initiated the development of high performance polymer fibers. For example, a liquid crystal polymer solution of a rigid rod polymer can be prepared by spinning the liquid crystal polymer solution into dope filaments, removing the solvent from the dope filaments, washing and drying the fibers; Heat treated to increase tensile properties to form high strength fibers. An example of a high performance polymer fiber is a para-aramid fiber such as poly(p-phenylene terephthalamide) ("PPD-T" or "PPTA"). [0003] Fibers derived from 5(6)-amino-2-(p-aminophenyl)benzimidazole (DAPBI), p-phenylenediamine (PPD) and terephthaloyl dichloride (TCl) are known in the art. Hydrochloric acid is produced as a by-product of the polymerization reac...

Claims

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Application Information

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IPC IPC(8): D01D10/06D01F6/80
CPCD01D10/06D01F6/805D01F11/08
Inventor S.R.阿伦V.加巴拉J.L.洛厄里S.R.鲁斯蒂格C.W.纽顿D.J.罗迪尼A.J.斯特
Owner DUPONT SAFETY & CONSTR INC
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