What is Scouring?Normally natural fiber contains dust, oil, wax, minerals and many impurities as well. we have to cleanse these for further process. So the way of removing those impurities is called scouring. The most important wet process used on textile products before dyeing or printing is scouring.
scouring process pdf
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Cotton fabric scouring is a chemical cleaning procedure that removes natural wax and non-fibrous impurities from the fabrics, as well as any additional soiling or dirt. Cotton fabric is usually scoured in kiers, which are large iron vessels.
The aim of this study was to assess the simulation and prediction of scour processes, both hydrodynamically and morphologically, around vertical and inclined piers. A new version of FLOW-3D v. 11.2, including three sediment transport equations, was extensively used for estimating the scour around the pier. The results of the model in terms of water surface, flow velocity, bed shear stress and scour depth were effectively compared with several sets of the experimental and numerical data in the literature. The model provided an accurate estimation of water surface, flow velocity and bed shear stress. However, the results for the vertical velocity upstream of the pier were underestimated. The predictive capabilities of the model were mainly dependent on the pier shape and inclined direction. The downflow, stream-wise velocity, shear stress and local scour depth were significantly reduced at the inclination angle of the circular pier downstream. However, they were nearly equal to those of an inclined perpendicular circular pier. This study strongly demonstrates that a 3D hydromorphological model can be effectively used to predict the scour depth around piers.
Textile manufacturing was once an everyday household activity.[16] In Europe, women were often involved in manufacturing manufacturing. They used to spin, weave, process, and finish the products they needed at home.[17][18][19][relevant?]In the pre-industrial era, scouring (wool scouring) was a part of the fulling process of cloth making, in which the cloths were cleaned, and then milled (a thickening process). Fulling used to be done by pounding the woolen cloth with a club, or by the fuller's feet or hands. This process was associated with waulking songs, which were sung by women in the Scottish Gaelic tradition to set the pace.[20][21][22][23]
The removal of lanolin, vegetable materials and other wool contaminants before use is an example of wool scouring.[25][26] Wool scouring is the next process after the woollen fleece of a sheep is cut off.[27] Raw wool is also known as ''Greasy wool.''
Potash and wool fat are two beneficial substances among the contaminants in wool, necessitating the development of specific cleaning techniques capable of recovering these compounds. Steeping is an alternative scouring process, In steeping system, scouring entails in parts. Wool steeping is carried out in stages such as immersing it in lukewarm water for many hours.[32] [33] When the wool includes only a little amount of yolk, the steeping method for recovering the yolk can be skipped.[34]
Biotechnology in textiles is the advanced way of processing, textiles, it contributes to numerous treatments of cellulosic materials such as desizing, denim washing, biopolishing, and scouring, etc.[44]
Enzymes are helpful in bio-singeing, bio-scouring and removing impurities from cotton, which is more environmentally friendly.[45] Biopolishing is an alternative method that is an enzymetic treatment to clean the surface of cellulosic fabrics or yarns. It is also named ''Biosingeing.''[46][47] Pectinase enzymes, breaks down pectin, a polysaccharide found in cellulosic materials such as cotton.[48]
Denim jean production has been largely outsourced to China, Vietnam, India, Pakistan, Turkey, Mexico, Indonesia, and Bangladesh for years due to the low labor cost in those countries. Further, the denim brands have continually pressured the denim mills to reduce their margins and cost of the base denim fabric as well as the price of the final denim products. Accordingly, there appears to be little room to significantly reduce denim jean manufacturing costs in any measurable way. Compounding this issue is the fact that denim brands desire a higher degree of sustainability. Of course, the improvement needed in the environmental conditions in denim jean manufacturing is often associated with increased costs due to new processes, new chemicals, or equipment, none of which are traditionally associated with reduced costs.
The inventors surmised that the opportunity to reduce denim mill and garment manufacturing costs and perhaps improve sustainability lies in the denim garment laundry process. A substantial amount of the costs associated with the garment production is incurred at this stage as it takes several hours to complete the dry process and garment wash cycles which employ abrasive media, chemicals and from 7-15 gallons of water per jean. Before determining what factors to change to achieve significant wash savings along with improved sustainability, the inventors first had to understand the processes in the manufacture of denim fabric, which is later sewn into garments, often dry abraded, and later washed.
This pre-dye process is generally referred to as scouring or preparation. The warp yarns are exposed to what is commonly known as a wash, detergent, or scour bath in order to remove the natural field and plant contaminants, impurities, dirt, fats and/or waxes. Prior art teaches that in order to achieve the desirable denim jean colors, the scour must penetrate the yarn completely or with deep penetration into the core in order to remove the waxes and impurities, which then allows the dye to accumulate in deep bands on the yarn and somewhat into the core. This deep yarn penetration of the dyes is thought to be the only way to achieve the dark dyed denim garment colors desired. Penetration of the scouring agents is assisted through the use of high temperatures of about 60-80 C. and higher and with the heavy use of alkaline chemicals employed in the scour bath or vat. These chemicals are traditionally comprised of a wetting agent with a concentration of approximately 8 g/L and caustic mixture of about 50% NaOH at a concentration of approximately 180 g/L. The high temperature alkaline bath with the wetting agent swells the yarns for better removal of the contaminants, debris, and waxes in the yarn and increases acceptance of the dyestuffs. After exposure to the scour bath, the yarns may be processed through a series of heated or steam filled rollers to provide a high temperature dwell time for the chemicals to be allowed sufficient time to react and clean the yarns before rinsing and immersion in the dye tank. Alternately the yarns may be processed through a series of rollers without any heat or steam just to provide increased dwell time. Traditional rinsing involves the yarns passing through one or more traditional clean water rinsing vats, and then ultimately processed through a set of nip rollers to squeeze excess water and chemicals before proceeding to the dyeing vats. The prior art teachings do not disclose in any way the impact of changing the scouring objectives as above or associating the yarn diameter or cotton quality with the scouring process parameters.
Upon completion of the scouring or preparation stage, the yarns then continue on to the dyeing stages, and beyond. All of these efforts produce a ring dyed yarn that once woven into denim fabric and then fabricated into denim garments will require significant amounts of water, chemicals, time, and energy to wash down the dyed denim garment to the color and characteristics standards specified by denim brands. Further the denim garments require additional dry processing through hand sanding, or laser abrading to achieve the worn look, along with the employment of the toxic chemicals potassium permanganate or sodium hydrochlorite, to brighten the abrasion area.
One subset of denim garments is FR, or flame resistant garments. Flame resistant garments are often worn in mining, public utility, gas, oil and other at-risk industries and environments. The process of applying chemicals such as halogenated hydrocarbons, organohalogen organophosphate, antimony oxides, and phosphate-based compounds and chemicals result in a garment with properties associated with increased dye fastness and or increased core penetration of dye. Those skilled in the art recognize that there are other chemicals and compounds used in the textile industry to achieve FR qualities. As a result, FR treated garments are increasingly resistant to color reduction methods in both dry and wet processing mentioned above. This increased resistance to color removal often leads to FR garments devoid of contemporary washes and finishes as they are either impossible or cost prohibitive to produce.
Through a series of numerous trials and analysis, the inventors discovered a number of absolutely novel denim mill ring dye related scouring process changes that significantly reduce denim jean costs by reducing water, energy, time and chemicals during the denim garment washing process. Not only are the denim garment manufacturing costs markedly reduced by the employment of this invention but uniquely the sustainability is also improved. This is a major breakthrough in denim garment production. Even further cost reductions were confirmed at the denim mill and the dry process where lasers are used to create the worn look, which can be local or global in effect.
Inventors realized that associating dye color with depth of yarn penetration of dye in the prior art will not produce the benefits of this invention and specifically any reduction in garment dry process and/or wash process savings. Prior art and conventional denim ring dye mill practices created intends to allow deep penetration of indigo and/or sulfur dyestuffs towards or into the yarn center or core. The inventors realized that these current well accepted practices result in increased dry process, garment wash, and finishing related costs for the deeper indigo penetrates a yarn, the longer and more aggressively the yarn needs to be washed to reveal the white, natural or off-white colored core. These conventional practices of dyeing often dye, or partially dye, the very core of the yarn leaving finishing facilities little choice in their efforts to show the white interior yarn for high/low contrast other than bleaching the yarns with potassium permanganate. These more aggressive garment wash abrasion cycles or bleaching treatments will reduce yarn tensile strength, so fabric is less durable to wear. However, contrary to this well accepted practice, the inventors discovered the importance of thoroughly cleaning only the outside perimeter of the yarn, while leaving the core of the yarn filled with the original waxes and impurities. This novel inventive concept resists dye penetration and dye fixing into the white or natural colored yarn core and consequently preserves a larger portion of the white core than common practices or prior art. Hence the dry finishing or laundry process will be markedly improved since it will take less water, chemicals, time and energy to wash down or otherwise remove the indigo. This reduction in energies and chemicals used also improves overall fabric strength with the reduced damage to the cotton fibers. Inventors realized that attempts at preserving the white or natural colored core through various methods had the added benefit of also retaining the consistent circular shape of the core, or a core shape that follows the perimeter of the yarn, to achieve a more uniform dye and fastness. This finding is another embodiment of the invention. Additional benefits of a circular shaped core, or a core shape that more accurately represents the shape of the perimeter of the yarn will be expanded later, suffice to say this is a breakthrough over prior art. 2ff7e9595c
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