Effect of Dyeing Temperature and Dye Concentration on Color Characteristics and Fastness of Annatto-Dyed PET/Wool (55/45) Fabrics

Articles in Press

Document Type : Original Article

Authors

1 Textile Engineering, University of Bonab, Bonab, Iran

2 chemical Engineering, Faculty of Textile Engineering, Urmia University of Technology, urmia, iran

3 Textile Engineering, Carpet Group, Department of Art, Shahrekord University, Shahrekord, Iran

Abstract

Abstract

Polyester/wool blended fabrics (55:45), conventionally dyed with reactive and disperse dyes, present challenges related to toxicity and environmental sustainability. This study investigates an eco-friendly dyeing approach for PET/Wool fabrics using natural colorants extracted from annatto seeds. The fabrics were dyed at concentrations ranging from 1–30% owf and at temperatures of 90°C, 110°C, and 130°C for 30 minutes using the exhaust dyeing method. Colorimetric analysis showed that increasing dye concentration and temperature generally produced darker, more saturated shades, as reflected in decreasing L* values. Changes in color strength (K/S) indicated that maximum dye uptake occurred at 90°C for low concentrations, while higher concentrations (15–30%) exhibited superior absorption at 110°C, with limited additional benefit at 130°C. Fastness evaluation revealed that wash and rubbing fastness improved significantly at elevated temperatures due to enhanced dye penetration into both fiber components. Sublimation fastness similarly increased with temperature, indicating stronger dye–fiber interactions at 110°C and 130°C. Light fastness remained the principal limitation, with poor resistance across most conditions, showing only moderate improvement at low dye concentration (1%) and the highest dyeing temperature. Overall, the findings highlight dyeing temperature as a critical factor in optimizing color depth and fastness performance in annatto-dyed PET/Wool blends. The study demonstrates the potential of annatto as a natural and environmentally benign alternative for producing moderately fast and aesthetically appealing shades on polyester–wool blended textiles.



Keywords: One bath dyeing, Annatto dye, Polyester-wool fabric, Color Fastness, Colorimetric Analysis

Keywords

Main Subjects

Progress in Color, Colorants and Coatings

Articles in Press, Accepted Manuscript
Available Online from 25 April 2026

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