Pretreatment and dyeing of shaped articles derived from wholly aromatic polyamides

Abstract

Abstract Processes are disclosed for the conversion of thermally stable shaped articles derived from wholly aromatic polyamides into level dyeing, deeper dyeing products having improved resistance to discoloration by sunlight or ultraviolet radiation. The processes involve treatment of the shaped articles at elevated temperatures at atmospheric pressure under carefully controlled conditions, and include a pretreatment or conditioning treatment carried in a hot bath of a high boiling organic liquid followed by dyeing the shaped articles in another hot bath cotaining a conventional organic dyestuff dissolved or dispersed in a high boiling organic liquid which may be the same or a different high boiling organic liquid. High boiling glycols, glycol ethers, solvents or solvent blends are especially suitable. Additionally, the hot dyebath preferably includes a further additive to minimize the effect of harmful radiation. The processes may be carried out batchwise or continuously, and may be employed for the treatment of the shaped article in the form of continuous filament yarn, staple yarn, tow, fabric, etc. Special features of the invention are the relatively short time of treatment (especially in the case of continuous operation) thus providing a commercially feasible process and the avoidance of the need for employing solid organic or inorganic pigments for coloring the thermally stable shaped articles.

Inventors

• 👤 J Hermes

Bibliographic Details