Process for making DAPBI-containing aramid crumbs

1. A method for obtaining an aromatic polyamide containing para-phenylene terephthalamide and 2-(p-phenylene)benzimidazole terephthalamide units, in the form of a crumb, by copolymerizing:

i) a mole % of para-phenylenediamine;

ii) b mole % of 5(6)-amino-2-(p-aminophenyl)benzimidazole; and

iii) 90-110 mole % of terephthaloyl dichloride

in a mixture of N-methyl pyrrolidone and containing c wt. % of calcium chloride,

wherein c is within the range from 1 to 20, and wherein the ratio a:b ranges from 1:20 to 20:1, a+b is 100 mole %, and i), ii), and iii) together comprise 1-20 wt. % of the mixture,

wherein the product b·c is at least 50 and less than 215 and the aromatic polyamide in the crumb has a relative viscosity ηrel of at least 4,

wherein the crumb is defined as non-sticky particles at least 95% of which having an average diameter of 0.7-15 mm, and

wherein the crumb is formed directly by the copolymerizing.

2. An aromatic polyamide containing para-phenylene terephthalamide and 2-(p-phenylene)benzimidazole terephthalamide units, in the form of a crumb, obtained directly by copolymerizing para-phenylenediamine; 5(6)-amino-2-(aminophenyl)benzimidazole; and terephthaloyl dichloride in a mixture of N-methyl pyrrolidone and calcium chloride,

wherein the aromatic polyamide in the crumb has a relative viscosity ηrel of at least 4, and

wherein the crumb is defined as non-sticky particles at least 95% of which having an average diameter of 0.7-15 mm.

3. The aromatic polyamide of claim 2 , wherein the aromatic polyamide in the crumb has a relative viscosity ηrel between 4 and 7.

4. A method for making purified aromatic polyamide by coagulating and washing the crumb of claim 2 in water, followed by a drying step.

5. A method for making purified aromatic polyamide by coagulating and washing the crumb of claim 3 in water, followed by a drying step.

6. A method for obtaining a composition comprising the purified aromatic polyamide obtained by the method of claim 4 , the method comprising:

dissolving the purified aromatic polyamide in the form of a crumb in a solvent.

7. The method of claim 6 , wherein the solvent is selected from the group consisting of sulfuric acid, N-methyl pyrrolidone, dimethylacetamide and combinations thereof.

8. A method for obtaining a composition comprising the purified aromatic polyamide obtained by the method of claim 5 , the method comprising:

dissolving the purified aromatic polyamide in the form of a crumb in a solvent.

9. The method of claim 8 , wherein the solvent is selected from the group consisting of sulfuric acid, N-methyl pyrrolidone, dimethylacetamide and combinations thereof.

10. A method for obtaining an aromatic polyamide containing para-phenylene terephthalamide and 2-(p-phenylene)benzimidazole terephthalamide units, in the form of a crumb, the method consisting of copolymerizing:

i) a mole % of para-phenylenediamine;

ii) b mole % of 5(6)-amino-2-(p-aminophenyl)benzimidazole; and

iii) 90-110 mole % of terephthaloyl dichloride

in a mixture of N-methyl pyrrolidone and containing c wt. % of calcium chloride,

wherein c is within the range from 1 to 20, and wherein the ratio a:b ranges from 1:20 to 20:1, a+b is 100 mole %, and i), ii), and iii) together comprise 1-20 wt. % of the mixture,

wherein the product b·c is at least 50 and less than 215 and the aromatic polyamide in the crumb has a relative viscosity ηrel of at least 4, and

wherein the crumb is defined as non-sticky particles at least 95% of which having an average diameter of 0.7-15 mm.