Search results

The purpose of this study is to optimize single-bath dyeing process of wool and silk blend, to achieve uniform colour strength for both the fibre after the dyeing process. Due to different absorption characteristics of wool and silk, two-stage dyeing is preferred in the industry. If the fibres are dyed together, the wool fibre becomes darker and the silk fibre becomes lighter after the dyeing process. Solid dyeing effect can be achieved using a single-bath dyeing process.

The dye-acceptor sites in the wool fibre are first blocked using one commercial syntan Mesitol HWS. Then, the syntan-treated wool and silk fibres (80:20 blend ratios) are dyed with Telon Navy AMF dyes in the presence of sodium sulphate. To explore the influence of Syntan, sodium sulphate and the experimental conditions on the dyeing process and to optimize the process, central composite design (CCD) of four factors and three levels was tested.

The design process is optimized using four independent variables: Mesitol HWS concentration, sodium sulphate concentration, pH of dyebath and temperature of dyeing. Three levels of Mesitol HWS concentration (5, 10 and 15 per cent), sodium sulphate concentration (10, 20 and 30 per cent), pH (2.5, 4 and 5.5) and temperature of dyeing (70, 80 and 900°C) were selected for this study. These variables are optimized using response surface regression equation of the ratio of K/S wool and K/S silk. The predicted equation matched well with the experimental data.

This paper proposes the use of one-bath dyeing process of wool and silk blend fabric to reduce the dyeing time, process step and to save water.

In recent times, wool- and silk-blended fabrics are popular for creating glamourous products. Silk is blended to wool for creating more lustrous effect and to impart strength; on the other hand, wool is responsible for resilience, softness and warmth properties. Chemically both the fibres are protein-based, but the amount of amino acids is different. Due to this, the dye absorption behaviours of the two fibres from the same dye-bath are different. Wool is become darker than the silk fibre, if both the fibres are dyed together in a single bath dyeing process.

Here the wool fibres are first pre-treated with a commercial synthetic tanning agent (syntan) Mesitol HWS at three different pH values of 2.2, 3.2 and 4.2 and at three different concentrations: 5, 10 and 15 per cent. Then the syntan pre-treated wool fibres are dyed together with silk fibres maintaining the blend ratio as 80:20 by Telon Red MR, Telon Yellow M4GL and Telon Blue MRLW with sodium sulphate at three different concentrations of 10, 20 and 30 per cent.

The dye absorbency of the syntan-treated wool fibres decreased with increase in syntan concentration, whereas the colour strength of silk fibres increased. The resist effectiveness of wool fibres is increased from 6 to 59 per cent with increase of syntan concentration. So after the dyeing process, the colour strength of syntan-treated wool fibres are almost same with the colour strength of silk fibres. The washing fastness of the samples is improved, and wash fastness behaviour of both wool and silk fibres is almost same.

This paper gives an idea about the one bath dyeing process of wool- and silk-blended fabrics to achieve solid dyeing effect.