JPS5143422

1458330 Dyeing dry-spun aromatic polyainides BAYER AG 8 Aug 1975 [10 Aug 1974] 33153/75 Heading D1B Dry-spun filaments of fully aromatic polyamides or copolyamides optionally containing heterocyclic groups and not modified with acidic or basic groups, are dyed before or durinig stretching by passing through an aqueous bath containing at least one water-soluble dye, preferably cationic or anionic. The aqueous dyebath, preferably contains 0.01-5% of dissolved dye and the dyebath temperature is 20-100‹C; the dyebath may also contain 1-40% of a polar organic solvent particularly dimethylformamide, dimethylacetamide, N- methyl-pyrrolidone, or hexamethyl phosphoric acid tris-amide. The process is preferably carried out continuously and preferred polyamides are poly-m-phenylene isophthalamide or the heterocyclic polyamide derived from isophthalic acid dichloride and 3-(p-aminophenyl)-7-amino-2, 4-(1H, 3H)-quinazolinedione.