Improved Textile Fiber Dyeing with Ultrasonics
Ultrasonically assisted dyeing of fibers and fabrics improves the penetration of the dye into the fiber pores and increases colour strength and colour fastness significantly. Ultrasonic dyeing is a rapid process, which can be run under mild conditions and low temperatures. The fiber structure of materials such as fabrics and textiles is not damaged by sonication and remains intact. Ultrasonication intensifies the dyeing treatment achieving better color results and a fast process.
- Improved dye penetration into fibers
- Increased colour strength
- Improved colour characteristics
- Rapid dyeing process
- Improved dye uptake and color strength
- Higher wash, rubbing, and perspiration fastness
- Compatible with various fabrics (e.g. wool, silk, polyamide etc.)
- Lower overall processing costs
- Mild, environmental-friendly, green process
- Simple and safe operation
Ultrasonic Dyeing for Higher Colour Strength, Fastness and Quality
Ultrasonic Effects during Dyeing
Wetting & Mass Transfer: Ultrasonic cavitation and micro-streaming improves the penetration of the dye into the fiber and yarn pores of the material. Ultrasonic cavitation accelerates the rate of dye diffusion inside the fibre by perforating the external layer of the fibre, so that the dye can enter the fiber pores. Simultaneously, sonication speeds up the chemical reaction between dye and fibre.
Dispersion: Sonication breaks up droplets, agglomerates and aggregates preparing a uniform dispersion in the dye.
Degassing: Ultrasound waves release dissolved or entrapped gas molecules from the fibre into liquid so that the gas can cavitation, thus facilitating dye-fibre contact and penetration for a fast and complete fiber coloration.
Tissera et al. (2016) demonstrated that sonication is able to achieve good color strength on cotton fabric at very low temperature such as 30ºC, which was approximately 230% more than the color strength achieved in normal heating method of dyeing. Mild sonication of 0.7 W/cm2 with the UP400St under mild temperature conditions at approx. 30ºC gave significantly improved results for colour strength and a deep penetration of the dye into the cotton fabric.
A particle size analysis of the dye revealed that ultrasonication deagglomerates and disperses the hydrolyzed dye molecules during dyeing and helps the dye to penetrate deeper into the fabric. At the same time, the fiber surface and fiber morphology remains unchanged and fully intact after sonication.
Ultrasonic Dyeing for Various Fiber and Fabric Types
Ultrasonication is a efficacious, yet mild technique to dye fibers and fabrics with colorants such as organic and inorganic dyes.
Research and pilot studies have tested the ultrasonic dyeing technique successfully for various fiber and fabric types.
Ultrasonication improved the dyeing process of
- (organic) cotton & knitted cotton fabrics
- synthetic fabrics, e.g nylon, polyester, polyamide
- natural fibers, e.g. hemp, bamboo
- cellulosic fabrics
SEM analysis shows that ultrasonically-assisted dyeing does not affect surface structure of (nano-)fibers.
High-Performance Ultrasonicators for Dyeing Fibers and Fabrics
Hielscher Ultrasonics is your long-time experienced partner when it comes to high-performance ultrasonic processing. We offer the full portfolio from laboratory and bench-top ultrasonicators for research, feasibility testing and process optimization to fully-industrial ultrasonic processors for large volume processing. For the ultrasonic dyeing of textiles and fabrics Hielscher offers various solutions depending on the fiber or textile and the dye.
Hielscher Ultrasonics’ industrial ultrasonic processors can deliver very mild to very high amplitudes. Built for heavy-duty applications, amplitudes of up to 200µm can be easily continuously run in 24/7 operation. For even higher amplitudes, customized ultrasonic sonotrodes are available. The robustness of Hielscher’s ultrasonic equipment allows for 24/7 operation under heavy load and in demanding environments.
Our customers are satisfied by the outstanding robustness and reliability of Hielscher Ultrasonic’s systems. The installation in fields of heavy-duty application, demanding environments and 24/7 operation ensure efficient and economical processing. Ultrasonic process intensification reduces processing time and achieves better results, i.e. higher quality, higher yields, innovative products.
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- Akalın M., Merdan N., Kocak D., et al. (2004): Effects of ultrasonic energy on the wash fastness of reactive dyes. Ultrasonics 2004; 42: 161-164.
- Atav R., Yurdakul A. (2016): Ultrasonic Assisted Dyeing of Angora Fibre. Fibres & Textiles in Eastern Europe 2016; 24, 5(119): 137-142.
- Nadeeka D. Tissera, Ruchira N. Wijesena, K.M. Nalin de Silva (2016): Ultrasound energy to accelerate dye uptake and dye–fiber interaction of reactive dye on knitted cotton fabric at low temperatures. Ultrasonics Sonochemistry 29, 2016. 270–278.
- Wafa Haddar; Noureddine Baaka; Nizar Meksi; Manel Ben Ticha; Ahlème Guesmi; M. Farouk Mhenni (2015): Use of Ultrasonic Energy for Enhancing the Dyeing Performances of Polyamide Fibers with Olive Vegetable Water. Fibers and Polymers 2015, Vol.16, No.7. 1506 -1511.
Facts Worth Knowing
Fabric dyes (also textile dyes) are liquid substances used to color textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. The dyes penetrate into the fabric and change it chemically, which results in a permanent coloring.
Commonly, acrylic fibers are dyed with basic dyes, while nylon and protein fibers such as wool and silk are processed with acid dyes, and for polyester yarn disperse dyes are used. Cotton can be dyed with various types of dyes, including vat dyes, and modern synthetic reactive and direct dyes.
Reactive dyes are the most important dye type for cellulose fibres such as cotton and viscose, but they are also increasingly gaining importance for wool and polyamide. Due to the broad range of reactive dye types, they can be used for manifold dyeing techniques. Reactive dyes can be distinguished into two major types: hot (monochlorotriazine dyes) and cold reactive dyes (dichlorotriazine dyes). Using cold reactive dyes allows to run dyeing processes at room temperature because cold-type dyes are more reactive due to the presence of two chlorine atoms.
Reactive dyes are known for poor dye fixation. The problem of dye fixation occurs especially in batch dyeing of cellulose fibres, where a significant amount of salt is normally added to improve dye exhaustion (and therefore also dye fixation).
Dyeing of Cellulose Fiber
In dyeing cellulose fibres with reactive dyes the following chemicals and auxiliaries are used:
- Alkali (sodium carbonate, bicarbonate and caustic soda)
- Salt (mainly sodium chloride and sulphate)
- Urea may be added to the padding liquor in continuous processes
- Sodium silicate may be added in the cold pad-batch method.
Below is a list of dyes with Colour Index International generic names and numbers.
|Alcian Blue 8GX
|Alcian yellow GXS
|Ingrain yellow 1
|Mordant red 11
|Alizarin Red S
|Mordant red 3
|Alizarin yellow GG
|Mordant yellow 1
|Alizarin yellow R
|Mordant orange 1
|Acid red 1
|Bismarck brown R
|Basic brown 4
|Bismarck brown Y
|Vesuvine Phenylene brown
|Basic brown 1
|Brilliant cresyl blue
|Cresyl blue BBS
|Basic orange 1
|Basic orange 2
|Direct red 28
|Basic violet 3
|Acid violet 19
|Basic violet 1
|Lissamine fast yellow
|Acid yellow 17
|Acid yellow 24
|Basic blue 6
|Acid yellow 36
|Acid orange 52
|Acid red 2
|Naphthalene black 12B
|Amido black 10B
|Acid black 1
|Naphthol green B
|Acid green 1
|Naphthol yellow S
|Acid yellow 1
|Acid orange 10
|Acid red 94
|Solvent orange 7
|Direct yellow 9
|Acid orange 6
|Acid orange 5
|Acid orange 7
|Victoria blue 4R
|Basic blue 8
|Victoria blue B
|Basic blue 26
|Victoria blue R
|Basic blue 11
|Xylene cyanol FF
|Acid blue 147