# Dyeing wool fabrics with specialized dyes and their mixtures using supercritical CO2

## TL;DR

Researchers expanded the color range of wool fabrics dyed with supercritical CO2 by using new dye mixtures, achieving durable colors like teal and green.

## Contribution

The study introduces new dye combinations for supercritical CO2 dyeing, enabling a broader palette of durable colors on wool fabrics.

## Key findings

- Maximum K/S value of 11.14 was achieved with a blue-to-red dye ratio of 80:20.
- Combining blue, red, and yellow dyes in supercritical CO2 produced durable hues like teal and green.
- Dyed samples showed excellent colorfastness and durability after washing.

## Abstract

Wool has been colored in supercritical carbon dioxide in a few trials, yielding only a small spectrum of colors, mostly orange and yellow, with minimal research on alternative color combinations. To further the industrial development of supercritical carbon dioxide (SCCO2) dyeing, a variety of dyes must be used to produce a diversity of colors. The material’s overall appearance is affected by shades of blue, yellow, and red. This study revealed the generation of new colors using three reactive disperse dyes with various colors: a blue dye derived from the anthraquinone parent body, a yellow dye with a pyrazole moiety, and a third, red, dye with an azo-thiazole moiety. These dyes and their blends were employed to dye wool fabric using supercritical carbon dioxide. The maximum K/S values were attained at 11.14 for the mixture of (blue dye: red dye 80:20), while the lowest K/S was indicated at 8.43 for (blue dye: red dye: yellow dye 1:1:2). However, the compatibility grade as per RCR values showed excellent values for the combination of three dyes. The dyed samples were evaluated for colorfastness, and the results showed that they retained their color well and were exceptionally durable after washing. The growing patterns in both the dyeing rate and build-up curves indicate good compatibility. Furthermore, desired hues of Teal, green, olive, gray, and reddish-brown can be created by combining blue, red, and yellow dyes in varied ratios in supercritical CO2.