Process for preparing aramid copolymer
View Patent ↗The invention concerns processes for forming a polymer comprising residues of terephthaloyl chloride, paraphenylene diamine, and a salt of formula I wherein A − is a halogen anion, HSO 4 − , OH − , NO 3 − , C 2 H 3 O 2 − , or H 2 PO 4 − ; the process comprising the steps of: a) forming a mixture comprising salt of formula I and paraphenylene diamine in a solvent system comprising an organic solvent and an inorganic salt; and b) adding terephthaloyl chloride to the mixture and allowing the formation of the polymer.
1. A process for forming a polymer comprising residues of terephthaloyl chloride, paraphenylene diamine, and a salt of formula I
wherein A − is a halogen anion, HSO 4 − , OH − , NO 3 − , C 2 H 3 O 2 − , or H 2 PO 4 − ;
said process comprising the steps of:
a) forming a mixture comprising salt of formula I and paraphenylene diamine in a solvent system comprising an organic solvent and an inorganic salt;
b) adding terephthaloyl chloride to the mixture and allowing the formation of said polymer.
2. The process of claim 1 , wherein a stoichiometric amount of terephthaloyl chloride is added to the mixture.
3. The process of claim 1 , wherein the organic solvent is N-methyl-2-pyrrolidone (NMP) or dimethylacetamide (DMAC).
4. The process of claim 1 , wherein the inorganic salt is LiCl or CaCl 2 .
5. The process of claim 1 , wherein the solvent system is NMP/CaCl 2 .
6. The process of claim 1 , wherein the salt of formula I is of the formula
7. The process of claim 2 , wherein said terephthaloyl chloride is added in two or more steps.
8. The process of claim 7 , wherein step b) comprises:
adding 20-50% of the terephthaloyl chloride in a first addition step to form a second mixture,
stirring the second mixture for at least 1 minute, and
adding the remaining terephthaloyl chloride in one or more addition steps to the stirred second mixture.
9. The process of claim 1 , wherein step b) is performed at a temperature between −10 and 30° C.
10. The process of claim 1 , wherein the salt of formula I and paraphenylene diamine are present in a molar ratio in the range of from 0.5 to 4.0.
11. The process of claim 5 , wherein NMP/CaCl 2 has a CaCl 2 weight percent in the range of from 1.0 to 10%.
12. The process of claim 1 , further comprising isolating said polymer.
13. The process of claim 12 , further comprising the step of comminuting the polymer.
14. The process of claim 12 , further comprising treating the polymer with one or more washing steps, neutralizing steps, or both.
15. The process of claim 13 , further comprising treating the comminuted polymer with one or more washing steps, neutralizing steps, or both.
16. The process of claim 14 , further comprising the step of dissolving the polymer in a solvent comprising sulfuric acid to form a solution suitable for spinning fibers.
17. The process of claim 15 , further comprising the step of dissolving the polymer in a solvent comprising sulfuric acid to form a solution suitable for spinning fibers.
18. The process of claim 14 , further comprising the step of dissolving the polymer in a solvent comprising N-methyl-2-pyrrolidone (NMP) or dimethylacetamide (DMAC) and an inorganic salt to form a solution suitable for spinning fibers.
19. The process of claim 15 , further comprising the step of dissolving the polymer in a solvent comprising N-methyl-2-pyrrolidone (NMP) or dimethylacetamide (DMAC) and an inorganic salt to form a solution suitable for spinning fibers.