| 摘要 |
The present invention concerns methods for obtaining high-tenacity aramid yarn, wherein the yarn is made of a copolymer obtained from a mixture of monomers comprising 5-(6)-amino-2-(p-aminophenyl)benzimidazole, an aromatic para-diamine, and an aromatic para-diacid. The method comprises: a) spinning said copolymer from an inorganic acid solvent to produce the aramid yarn; b) washing the yarn with a basic aqueous solution for at least 5 seconds; and c) heating the yarn; wherein the yarn is heated in at least two process steps, comprising (i) in a first step the yarn is heated at a temperature of 200 to 360° C. at a tension of at least 0.2 cN/dtex, followed by (ii) a second step wherein the yarn is heated at a temperature of 370 to 500° C. at a tension of less than 1 cN/dtex. |
