Process of forming an aramid copolymer
View Patent ↗The invention concerns processes for forming a polymer comprising residues of 2-(4-amino phenyl)-5 (6) amino phenyl benzimidazole (DAPBI), paraphenylene diamine, and terephthaloyl dichloride, comprising the steps of: a) forming a solution of DAPBI and paraphenylene diamine dihydrochloride in a solvent system comprising an organic solvent and an inorganic salt; b) cooling the solution to a temperature of 30° C. or less; c) adding a stoichiometric amount of terephthaloyl dichloride, relative to the total amount of the DAPBI and the paraphenylene diamine dihydrochloride, to the solution; and d) agitating the solution of step c) to form a polymer.
1. A process for forming a polymer comprising residues of 2-(4-amino phenyl)-5 (6) amino benzimidazole (DAPBI), paraphenylene diamine, and terephthaloyl dichloride, comprising the steps of:
a) forming a solution of DAPBI and paraphenylene diamine dihydrochloride in a solvent system comprising an organic solvent and an inorganic salt;
b) cooling the solution to a temperature of 30° C. or less;
c) adding a stoichiometric amount of terephthaloyl dichloride, relative to the total amount of said DAPBI and said paraphenylene diamine dihydrochloride, to the solution; and
d) agitating the solution of step c) to form a polymer.
2. The process of claim 1 , wherein the organic solvent is N-methyl-2-pyrrolidone (NMP) or dimethylacetamide (DMAC).
3. The process of claim 1 , wherein the inorganic salt is LiCl or CaCl 2 .
4. The process of claim 1 , wherein the solvent system is NMP/CaCl 2 .
5. The process of claim 1 , further comprising isolating said polymer from said solvent system.
6. The process of claim 1 , wherein step a) said solution is formed by heating DAPBI and paraphenylene diamine dihydrochloride in said solvent system.
7. The process of claim 1 , wherein terephthaloyl dichloride is added stepwise.
8. The process of claim 1 , wherein terephthaloyl dichloride is added in a single step.
9. The process of claim 5 , further comprising the step of comminuting the polymer.
10. The process of claim 5 , further comprising treating the polymer with one or more washing steps, neutralizing steps, or both.
11. The process of claim 9 , further comprising treating the polymer with one or more washing steps, neutralizing steps, or both.
12. The process of claim 10 , further comprising the step of dissolving the polymer in a solvent comprising sulfuric acid to form a solution suitable for spinning fibers.
13. The process of claim 11 , further comprising the step of dissolving the polymer in a solvent comprising sulfuric acid to form a solution suitable for spinning fibers.
14. The process of claim 1 , wherein DAPBI and phenylene diamine are present in a molar ratio in the range of from 0.25 to 4.
15. The process of claim 4 , wherein NMP/CaCl 2 has a CaCl 2 weight percent in the range of from 1 to 10%.
16. The process of claim 1 , wherein the amount of DAPBI used in forming the solution in step (a) is in the range of from 0.3 to 9.0 weight %.
17. The process of claim 1 , wherein the amount of paraphenylene diamine dichloride used in forming the solution in step (a) is in the range of from 0.2 to 10.0 weight %.
18. The process of claim 1 , wherein the solution is cooled to a temperature of 10° C. or less.