Process for preparing yarn derived from aramid copolymer fiber having low residual sulfur
View Patent ↗The present invention concerns processes for producing a yarn comprising polymer comprising imidazole groups, the process having the following steps: (a) spinning a solution of polymer in sulfuric acid to give rise to a plurality of dope filaments; (b) coagulating the plurality of dope filaments into a multi-filament as-spun yarn; and (c) washing the as-spun multi-filament yarn with an aqueous acid comprising a halide or an aqueous salt comprising a halide or combination thereof.
1. A process for producing a yarn comprising polymer, said polymer comprising imidazole groups, the process having the following steps:
(a) spinning a solution of polymer in sulfuric acid to give rise to a plurality of dope filaments;
(b) coagulating the plurality of dope filaments into a multi-filament as-spun yarn; and
(c) washing the as-spun multi-filament yarn with an aqueous acid comprising a halide or an aqueous salt comprising a halide or combination thereof.
2. The process of claim 1 wherein said polymer comprises derivatives of 5(6)-amino-2-(p-aminophenyl)benzimidazole, aromatic diamine, and aromatic diacid-chloride.
3. The process of claim 1 , wherein said as-spun multi-filament yarn after washing step (c) has a sulfur content of less than 3 weight percent.
4. The process of claim 3 , wherein said as-spun multi-filament yarn after washing step (c) has a sulfur content of less than 1 weight percent.
5. The process of claim 4 , wherein said as-spun multi-filament yarn after washing step (c) has a sulfur content of less than 0.1 weight percent.
6. The process of claim 1 , where said as-spun multi-filament yarn after washing step (c) has a sulfur content of 0.05 to 3 weight percent.
7. The process of claim 1 where said as-spun multi-filament yarn after washing step (c) has a sulfur content of 0.01 to 0.08 weight percent.
8. The process of claim 2 , wherein said aromatic diacid-chloride is terephthaloyl dichloride.
9. The process of claim 2 , wherein said aromatic diamine is para-phenylenediamine.
10. The process of claim 2 , wherein the molar ratio of 5(6)-amino-2-(p-aminophenyl)benzimidazole to aromatic diamine is in the range of from 30/70 to 85/15.
11. The process of claim 10 , wherein the molar ratio of 5(6)-amino-2-(p-aminophenyl)benzimidazole to aromatic diamine is in the range of from 45/55 to 85/15.
12. The process of claim 1 , wherein the acid comprising a halide is one or more of hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, or mixtures thereof.
13. The process of claim 12 , wherein said acid comprising a halide is hydrochloric acid.
14. The process of claim 1 , wherein the halide acid is formed from a material that forms a halide-containing acid when in contact with water.
15. The process of claim 1 , wherein said salt comprising a halide is sodium chloride, sodium bromide, potassium chloride, potassium bromide, lithium chloride, lithium bromide, calcium chloride, calcium bromide, magnesium chloride, magnesium bromide, ammonium chloride, ammonium bromide, ferrous chloride, ferrous bromide, ferric chloride, ferric bromide, zinc chloride, zinc bromide, or mixtures of two or more of these.
16. The process of claim 15 wherein the salt comprising a halide is sodium chloride.
17. A process for producing a yarn comprising polymer comprising imidazole groups, the process having the following steps:
(a) spinning a solution of polymer in sulfuric acid to give rise to a plurality of dope filaments;
(b) coagulating the plurality of dope filaments in a coagulation bath containing an aqueous acid comprising a halide or an aqueous salt comprising a halide or combination thereof to form a multi-filament as-spun yarn.
18. The process of claim 17 wherein said polymer comprises derivatives of 5(6)-amino-2-(p-aminophenyl)benzimidazole, aromatic diamine, and aromatic diacid-chloride.
19. The process of claim 18 , where said as-spun multi-filament yarn after step (b) has a sulfur content of less than 3 weight percent.
20. The process of claim 19 , where said as-spun multi-filament yarn after step (b) has a sulfur content of less than 1 weight percent.
21. The process of claim 20 , where said as-spun multi-filament yarn after step (b) has a sulfur content of less than 0.1 weight percent.
22. The process of claim 17 , where said as-spun multi-filament yarn after washing step (b) has a sulfur content of 0.05 to 3 weight percent.
23. The process of claim 17 , where said as-spun multi-filament yarn after step (b) has a sulfur content of 0.01 to 0.08 weight percent.
24. The process of claim 18 , wherein said aromatic diacid-chloride is terephthaloyl dichloride.
25. The process of claim 18 , wherein said aromatic diamine is para-phenylenediamine.
26. The process of claim 18 , wherein the molar ratio of 5(6)-amino-2-(p-aminophenyl)benzimidazole to aromatic diamine is in the range of from 30/70 to 85/15.
27. The process of claim 26 , wherein the molar ratio of 5(6)-amino-2-(p-aminophenyl)benzimidazole to aromatic diamine is in the range of from 45/55 to 85/15.
28. The process of claim 17 , wherein the acid comprising a halide is one or more of hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, or mixtures thereof.
29. The process of claim 28 , wherein said acid comprising a halide is hydrochloric acid.
30. The process of claim 17 , wherein the halide acid is formed from a material that forms a halide-containing acid when in contact with water.
31. The process of claim 17 , wherein said salt comprising a halide is sodium chloride, sodium bromide, potassium chloride, potassium bromide, lithium chloride, lithium bromide, calcium chloride, calcium bromide, magnesium chloride, magnesium bromide, ammonium chloride, ammonium bromide, ferrous chloride, ferrous bromide, ferric chloride, ferric bromide, zinc chloride, zinc bromide, or mixtures of two or more of these.
32. The process of claim 31 wherein the salt comprising a halide is sodium chloride.