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Fabric finishes and surface design
Published in Claudia E. Henninger, Kirsi Niinimäki, Marta Blazquez, Celina Jones, Sustainable Fashion Management, 2023
Claudia E. Henninger, Kirsi Niinimäki, Marta Blazquez, Celina Jones
Another wet process used is bleaching, to ensure a homogenous ground shade, typically used with fabrics containing cotton fibres. This will ensure that subsequent dyeing and printing produce a uniform- colour or print. Singeing can be a further step for cotton fibres, which ensures that any surface fibres are removed and the fabric is smooth in preparation for printing and dyeing. Mercerisation causes cotton fibres to swell, and not only alters the cross section of the fibre for improved interaction with light and better fabric lustre, but also increases the fibre's affinity to dyestuffs. The high pH of the strong alkali used in the mercerisation process affects the pH of effluent from the wet process (Eid and Ibrahim, 2021). It is important to note that all of these processes involve a large amount of water and chemicals prior to applying any aesthetic or performance finishes. This obviously raises environmental concerns if, for example, a piece of cotton greige fabric is subjected to all these wet processes such as desizing, bleaching, mercerisation, and singeing before any dyeing or printing takes place. There are a variety of colourants that can be applied to textiles, and we will focus on the application of a few examples of synthetic dyestuffs and pigments.
Recovery of Caustic Soda in Textile Mercerization by Combined Membrane Filtration
Published in Matthew Laudon, Bart Romanowicz, 2007 Cleantech Conference and Trade Show Cleantech 2007, 2019
J. Yang, C. Park, D. Lee, S. Kim
Mercerization is a process in which textiles (typically cotton) are treated with a caustic solution to improve properties such as fiber strength, shrinkage resistance, luster, and dye affinity. The caustic solution actually rearranges the cellulose molecules in the fiber to produce these changes. Higher-end fabrics may be double or triple mercerized for additional benefits. The fabric is first immersed in a caustic solution of about 18–25% strength and a relatively cool temperature of 16–32°C. A series of rollers (timing cans) are used to keep the fabric flat and smooth while controlling the time of caustic exposure. The fabric is then sprayed with rinse water and then washed with a neutralizing chemical before final drying (figure 1). In this study, a combined membrane process was applied, not only to improve the rejection efficiencies and flux recovery, but also to recycle the purified caustic solution back into the process.
Preparatory Chemical Processes and Recent Developments
Published in Asis Patnaik, Sweta Patnaik, Fibres to Smart Textiles, 2019
Naveen V. Padaki, Brojeswari Das, Subhas V. Naik, Sanganna A. Hipparagi
Mercerization is a process carried out exclusively for cotton textiles, where a strong alkali sodium hydroxide (NaOH) treatment is used to alter the fibre structure (Vincent et al. 2006). Mercerization process of treating cotton fibre with highly alkaline NaOH solution ensures internal modification in fibre structure due to hydrate and soda-cellulose formations, which are capable of entering the crystalline regions, cause fibre swelling, trigger modification in fibre structure, causes increase in amorphous regions and all these effects in turn increases cotton fibre moisture absorbency and uniform distribution of dyes and chemicals. Mercerization effects fibre swelling, which ensures removal of natural convolutions present in cotton fibres, better orientation of fibrils and molecular chains along the fibre axis and reformation of collapsed cotton fibre with bean-shaped cross section into cylindrical rod-shaped fibre with circular cross section. This change in cotton fibre structure due to mercerization results in increased fibre strength, improved lustre and better as well as uniform absorbency (Vincent et al. 2006). Mercerization process is not only popular as a preparatory for dyeing as it enhances absorption but also as a finishing process as it has greater impact on final strength and appearance of the finished cotton goods.
Dye adsorption and intensity in bobbin crusade in dyeing mixed acrylic and cotton yarn
Published in The Journal of The Textile Institute, 2021
Catia Rosana Lange de Aguiar, Antonio Augusto Ulson de Souza, Selene Maria Arruda Guelli Ulson de Souza
When assessing the results, it can be seen that when the fibers were dyed in the sequence PAC + CO + WHIT, the color intensity was close to 100%, confirming that the process, although not more efficient in terms of color intensity, had acceptable reproducibility. It was also possible to observe that the processes in which bleaching occurred before the dyeing provided better color intensity results with and without a fabric softener. However, if the industry opts for the mercerization process for the bleaching of cotton fibers, it must take into account the changes in the morphology of the cotton fiber, producing different final characteristics for marketing of the yarn, as well as the considerable environmental impact caused by excessive sodium hydroxide use in this process. Mercerization involves swelling of the cellulose fiber using a solution of concentrated sodium hydroxide. Although no dissolution occurs, swelling permits reorganization of the cellulose chains when the swelling agent is removed. This treatment leads to improved properties of cotton yarns and fabrics (Kolpak et al., 1978).