COMPOSITE HIGH-STRENGTH, HIGH-MODULUS HEAT-RESISTANT FIBRE MADE FROM HETEROCYCLIC AROMATIC COPOLYAMIDE AND METHOD FOR PRODUCTION THEREOF (VERSIONS) Russian patent published in 2013 - IPC D01F6/00 D01F6/74 C08G69/32 

FIELD: chemistry.

SUBSTANCE: method of production involves synthesis of a copolyamide by low-temperature copolycondensation of a mixture of 5(6)-amino-2(4-aminophenyl)benzimidazole, para-phenylenediamine and terephthaloyl chloride in an amide solvent solution with addition of 2.5-4.5 wt % LiCl or CaCl₂, moulding the obtained polycondensation solution, washing, drying, heat-treating and hot-stretching the obtained fibre. In one version, synthesis is carried out with addition into the reaction mass of a viscosity stabiliser in amount of 4-25 mol % of the mixture of diamines and excess terephthaloyl chloride in amount of 0.15-1.2 mol % of the mixture of diamines. In another version, the viscosity stabiliser is added in amount of 4-7.5 mol % of the mixture of diamines, and at the end of synthesis, terephthalic acid is added in amount of 0.15-1.2 mol % of the mixture of diamines and stirred until complete dissolution, and copolymer terminal groups are converted during heat treatment in an inert medium at temperature of 340-360°C. The result is obtaining an aramid fibre which is characterised by ultimate strength of 260 gf/tex or higher, initial modulus of elasticity of 16000 kgf/mm² or higher, wherein the increase factor of strength of the fibre in microplastic is 1.6 or higher, and breaking stress is 620 kgf/mm² or higher.

EFFECT: high ultimate strength and elasticity of the fibre.

10 cl, 1 tbl, 11 ex