Basic understanding of the finishing process in textile production
After the process of creating fabric from fibers, yarns, and even polymers, the dyeing and finishing processes are the next step to produce the finished fabrics. In addition to durability, customers also pay attention to the aesthetic as well as the hand feel of textile products, hence dyeing and finishing technology is increasingly emphasized and developed.
From a technical perspective, finishing aims to achieve three types of effects:
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Creating new features that the material originally does not have.
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Enhancing existing properties that do not meet usage requirements.
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Restoring existing features that were lost during processing.
In terms of application, finishing serves three purposes:
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Improving the fabric surface (smoothness, gloss, etc.)
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Improving properties related to garment making (softness, moisture absorption, insulation, breathability, dimensional stability, etc.)
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Improving properties related to usage and preservation (anti-wrinkle, no-iron, easy to clean, dust-free, flame-resistant, etc.).
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Some of the finishing techniques often being applied are: dimensional stability, giving the fabric a beautiful appearance such as smoothness and a cool hand feel. On top of that, it can also be wrinkle-free, shrink-free, water-repellent, anti-bacteria, mold resistant to name a few. The finishing process is divided into two types: mechanical finishing (dry finishing) and chemical finishing (wet finishing). In practical application, there are often situations where it is not clear whether a process is dry finishing or wet finishing.
At our finishing factory, the finishing process is responsible for the final quality of the fabric. Bao Minh Textile puts great emphasis on chemical techniques, safe handling of chemicals, labour safety, and all the issues related to air and wastewater. Besides that, we also make sure to invest in modern machinery for our finishing system to ensure consistent quality.
Some common finishing techniques:
Singeing is a finishing step that burns off the fiber ends on the surface of the fabric to achieve a smooth surface. The fabric is passed through brush rollers to raise the fiber ends, and then the fiber ends are burned off by passing the fabric over gas flames at a speed and contact condition appropriate for the machine.
Depending on the type of sizing used on the warp yarn to strengthen the fibers prior to weaving, the fabric can be soaked to hydrolyze the sizing in dilute acid and then rinsed clean, or enzymes can be used to break down the sizing and remove it.
Scouring is a process in the pre-treatment of cotton fabric to remove wax and non-cellulose impurities. The fabric is boiled in an alkaline solution, and a saponification reaction occurs between the alkali and the insoluble components, which can be removed to obtain pure cellulose. This process also helps to remove the sizing from the warp threads, although desizing is usually carried out as a separate step. In addition to the non-cellulose impurities, cotton fibers also contain the yellow color of natural dye compounds. Bleaching is also a necessary step after scouring.
Bleaching is a chemical process aimed at oxidizing the natural dye compounds in cotton fibers, making the cotton fibers whiter, and removing any remaining traces of impurities from the cotton. The required level of bleaching is determined by the whiteness required for subsequent dyeing processes. Additionally, the absorbency of the cotton fibers is also addressed, which facilitates subsequent processing. Bleaching is usually carried out with oxidizing agents such as sodium hypochlorite or hydrogen peroxide. If the fabric is dyed a dark color, a low-level bleaching may be sufficient, but if a high level of whiteness is required, an optical brightener or a whitening agent is necessary, which is called the whitening process.
Mercerizing is a processing step that helps the fabric achieve a high gloss due to the light reflection effect of cellulose fibers. In a concentrated, cool alkaline solution, the cellulose fibers swell to their full diameter, and the cross-section of the fibers changes from a flat or folded shape to a round one. The result is that the fibers are strengthened, the gloss is increased, the strength is increased, and the ability to absorb dye later is improved. The fabric is treated with mercerization while in a taut state and rinsed with an alkali solution after the reaction. The shrinkage of the fabric is also restored in this process, so it is sometimes referred to as the alkali shrinkage process. Mercerization can be carried out directly on the raw fabric or after bleaching.
The dyeing process varies depending on the nature of the dyes and the bond between the dyes and the fibers. High-performance and vibrant dyes such as reactive dyes and disperse dyes, are commonly used for cotton. Other dyes, such as direct dyes and sulfur dyes, have lower durability and color intensity. Each type requires different dyeing processes and other additives. The dyeing process also depends on the type of fabric and the desired color intensity and durability.
Bao Minh Textile's Special Finishing Techniques
In order to provide premium products that are safe for usages for the market, Bao Minh Textile makes sure to invest in our finishing system with advanced equipment and machinery. Our finishing system includes:
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Lafer's Liquid Ammonia machine for providing non-iron finishing.
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Lafer's Peaching Diamond Emery machine gives a soft and smooth feeling like feather to the fabric.
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Raising Machine to serve Flannels fabric types, Moist Cure Stenter specifically for moisture processing (moist cure finishing).
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Airo 24 Continuous Tumbler machine to handle softness.
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Calender machine to handle the surface gloss of the fabric.
All finishing stages at Bao Minh Textile are strictly controlled to ensure that the final product is of the best quality. On top of that, we make sure our production process always meets the safety requirements for usage as well as environmental protection and sustainable production.