A groundbreaking advancement in textile dyeing has emerged from collaborative research at Dalian University of Technology and Donghua University, offering a revolutionary approach to coloring cotton and polyester/cotton blends. The innovative method circumvents the longstanding challenge posed by the alkaline conditions traditionally required for reactive dyeing of cotton, which often leads to hydrolysis and incompatibility with one-bath dyeing processes involving polyester.
This new technique leverages silicon-containing reactive dyes combined with the silane coupling agent KH550 (3-aminopropyltriethoxysilane) to enable effective dye fixation under mildly acidic conditions (pH 5.0). Initially, KH550 undergoes hydrolysis, producing silanol groups. These groups form covalent bonds with hydroxyl groups on the cotton fibers, while the agent’s amino groups react with the reactive moieties on the dyes. Simultaneously, silanol groups undergo self-condensation, culminating in a robust three-dimensional covalent network uniting the dye, crosslinker, and fabric.
The results are compelling: all three silicon-containing reactive dyes tested—red, blue, and yellow—demonstrated fixation rates surpassing 91%, with the red dye achieving an impressive 96.4%. The treated cotton fabrics exhibited exceptional fastness properties, including dry rubbing fastness scores between 4 and 5, wet rubbing ratings from 3 to 4, and wash fastness above 4.5. Substantiating the chemical durability, exhaustive extraction tests and exposure to extreme pH conditions at elevated temperatures confirmed covalent bonding between the dye system and the fabric.
In-depth mechanistic analyses validated the pivotal chemical interactions driving this process. The silanol groups engage with cotton’s hydroxyls, reducing free KH550 concentration significantly after fabric treatment. Furthermore, amino groups on KH550 bridge with the reactive dye components, while silanol self-condensation fortifies the network, as evidenced by shifts in silicon binding energies detected through X-ray photoelectron spectroscopy (XPS).
Thermal analyses revealed the silicon-containing dyes maintain excellent stability below 200 °C, a critical feature allowing integration with thermosol processes used in disperse dye fixation on polyester. Notably, the thermosol treatment not only preserved the integrity of the reactive dyes but also slightly enhanced their fixation. Additionally, KH550 improved polyester’s wettability, reducing the contact angle of the dye dispersion significantly and enabling more efficient disperse dye uptake.
Extending this technology to polyester/cotton blends (65/35 ratio), the researchers achieved successful one-bath, one-step dyeing by coupling these silicon-reactive dyes with commercial disperse dyes. This approach yielded total dye utilization above 90%, with reactive dye fixation exceeding 96%, alongside superb color uniformity and robust fastness profiles. Compared to conventional multi-step methods, this novel process achieves substantial environmental benefits by halving water usage, cutting electricity consumption by nearly 50%, and reducing thermal energy demand by over one-third.
This innovative acidic cross-linking strategy, combining silicon chemistry with textile dyeing, heralds a promising, sustainable alternative for the industry. By enabling efficient, environmentally friendly dyeing of cotton and polyester blends within a simplified process, it holds potential to reshape textile manufacturing practices worldwide.
Article Title: Silicon-containing reactive dyes for acidic fixation on cotton and their application in one-bath one-step dyeing of polyester/cotton blends
News Publication Date: 7-Apr-2026
Web References: http://dx.doi.org/10.1007/s11705-026-2667-1
Keywords
Silicon-containing dyes, acidic fixation, reactive dyes, polyester/cotton blends, silane coupling agent, KH550, textile dyeing, environmentally friendly process
