Dyeing of Pa 6.6 fibres : effect on properties and behaviour of thermal treatme...

• Author(s): Gomes, Jaime Rocha ; Domingues, Maria do Sameiro Queirós ; Martins, J. A.
• Date: 2003
• Persistent ID: http://hdl.handle.net/1822/6150
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Dyeing; Polyamide; Solvent; Tg
• Document Type: Article
• Language: English

Description

The conventional dyeing of fibres in the textile industry is usually performed at high temperatures although it is possible to dye at low temperatures. The dyeing of fibres at low temperature presents some advantages from the industrial point of view, namely energy saving, environmental control and fibre protection (maintenance of the properties during the dyeing, finishing and final use). The conventional process of exhaustion dyeing of the microfibres of PA 6.6 takes place at temperatures that can go from 98 to 115ºC, in spite of it being possible to dye at lower temperatures, using for this effect dyes with low molecular weight, as it is the case of some acid dyes. However, in the dyeing with dyes of large molecule, as the metal complex dyes, it can result in defective dyeing due to their lower diffusion and migration properties. Dyeing at low temperatures without affecting the properties of dyeing, such as diffusion and levelness, has been shown to be possible with the aid of solvents. Polyester has been dyed with methylene chloride at temperatures of 40ºC [1] and wool has been dyed at lower temperatures with n-butanol and benzyl alcohol [2]. In this work we studied the use of benzyl alcohol as an auxiliary for lowering the dyeing temperature of PA fibres. This product is referred in the literature as a solvent of PA at it’s boiling temperature, and also a product that causes the disaggregation of acid dyes in the dyeing of PA fibres [3]. To this effect we carried out exhaustion dyeings with metal complex dyes for evaluating the minimum temperature of dyeing with benzyl alcohol and its effect on the exhaustion and diffusion of the dyes. Thermal analysis techniques were used to understand the effect of dyeing, with and without benzyl alcohol, on properties and thermal behaviour of PA6.6 microfibres.