Textile Points is a textile education blog. mercerization. International Journal of Textile Science. The recovery of caustic is some easier as impurities to some extent are removed by desizing. In dry mercerization, the process is carried out while drying the fabric on a stenter. The exit humidity of the fabrics was measured with humidity measurement device in a controlled way. Process of mercerization: Cotton fabric in stretched The mercerization has the following advantages: Improving luster Obtaining a silky look Improving the Tensile strength Retaining a greater proportion of tensile strength after easy care finishing Obtaining improved Dimensional Stability fAdvantages of Mercerization contd The technical data and the prescription are as follows: Prescription Â Â Â Â Â Â Â Â Â Â Â : 35 ml/l H2O2 50%, 15 ml/l NaOH 480Be, 2 ml/lÂ Â Â Â Gemsol WA, 2 ml/l Rohstoff ST-OS, 1 ml/l SevalinD. The epoxy resin (LY556) and the corresponding hardener (HY 951) are mixed in a ratio 10:1 by weight as recommended. When the boll bursts and exposes these fibers to sun and air they dry up and collapse, becoming flatter and ribbon like with alternating left and right spiral twist every two or three turns. It is an ultimate reference for textile students and professionals. The washed off NaOH is then passed to the CRP When goods are mercerized using hot mercerizing liquors, the goods can be stretched to a greater degree than when they are applied cold. After washing, caustic soda concentration in the fabric must be less than 8%, otherwise shrinkage occurs if tension is reduced. Good results are obtained through proper saturation, sufficient tension and complete washing. For this reason, full impregnation cannot be obtained. As the next pictures show, there is a difference in the cross section of the fibre before and after mercerization. Mercerization is a pre-treatment or finishing treatment of cellulosic materials with higher concentrated Alkali (NaOH) for short period at lower temperature. Washing under stretched condition after mercerization is very important. Effective mercerization requires the use of wetting agents. By treating the cotton under tension with strong NaOH solution without allowing it to shrink and then washing while still in the stretched condition. Table 8: Resistance to shrinkage in fabrics with plain weave. without scouring and bleaching after desizing it is called grey mercerization. Mercerizing is an important operation for cotton finishing achieving a resistant silk shine and good handle without all the fundamental processes being understood. such an extent that sometimes the lumen may even disappears. This test is done by using a microscope. However, flexibility decreases since the links among macromolecule chains, crystallites and fibrils are even stronger. Mercerization is a process in which textiles (typically cotton) are treated with caustic soda (NaOH) solution to improve properties such as fiber strength, shrinkage resistance, luster, and dye affinity. The scoured and bleached cotton fabric is passed through a padding mangle containing 55Â°-65Â°Tw the NaOH solution at 18Â°C for 2-3 min with tension. Moreover, using a wetting agent did not improve the stability. The hydroxyl groups independently dissociate to the extent of alkali sorption. Another common method of part mercerization is by mercerizing the cotton cloth in stripes. However, when goods are processed under tensions which are too great, dye sorption and affinity are decreased because the internal fiber structure is collapsed. Controlled cooling of the stretched fabric. Increasing of the lustre 4. Temperature has a great effect on swelling Optimum swelling takes place at around 15 – 20Â°C (Ideal temperature 15Â°C). The stretching is carried out not to exceed an elongation of 3-5%with reference initial length. Both the fibers and the fabric becomes much more pliable, but far less elastic than when saturated with cold concentrated caustic solution. The method was developed in the 19th century by John Mercer and H.A. This gives a large volume of dilute NaOH solution, which cannot be discharge into the drain for economy and pollution point of view. Caustisization is the treatment the cotton fabric with 15-17% NaOH It should not be injurious to the workers. In 1851, John Mercer was granted a British Patent for work he had done pertaining to cotton, linen and other vegetable fibrous materials that in effect caused certain changes in the character of the fiber when subjected to caustic soda, sulfuric acid, and/or other chemicals, etc. This project is proposing a possibility of mercerization of cotton fabric with lower caustic soda concentration than 20% through a mercerization at low temperature. Mercerization involves exposing cotton to sodium hydroxide. In 1890 Horace Lowe was granted a British patent in which he claimed that by applying Mercer’s caustic soda process to cotton yarn or fabric under tension a resultant high luster (a result of the light reflection off the smooth, round surface) was imparted to the fiber. Mercerized fabrics however Increasing of the tensile strength 5. New process and machinery based on discoveries concerning mercerization were described by I. Rusznak and C. Duckworth Â (proc. The cellulose of the wall swells inwards until the lumen is partially eliminated. Controlled hot stretching following saturation. The technical data are as follows: Speed Â Â Â Â Â Â Â Â Â Â Â Â : 40m/min. Traditional, tension controlled washing (chain or ahainless). However, not all shades require the same If temperature and concentration of caustic soda increase up to a certain limit the tensile strength of cotton increases. residual alkali may directly used for scouring. On the other hand, solutions of sodium hydroxide whose concentration is about 29% (wt/vol), i.e. Loose cotton fibers placed in the caustic solution contract considerably, thus increasing the strength of the fiber. Advantages of Ammonia mercerization * Less pollution. Mercerization is therefore an expensive chemical procedure. The fabrics that were taken from the rotation station were passed from the prescription and working conditions above in the bleaching machine and they were bleached. Second, at elevated temperatures, the concentrated caustic causes the fabric to become more plastic but less elastic causing the fabric to be easily stretched. Under the low tariff of the Democratic administration from 1893 to 1897, European mercerized cottons were introduced into America, and American manufacturers presently began to produce the same sorts of goods for home consumption. 2. Hot mercerizing generally produces increased dye sorption as the result of the plastic nature of cotton and its response to tension. Most of the goods were imported from Germany. As seen in Table 10, an improvement of 50 – 60% was seen in the direction of the warp compared to the raw fabric in the dobby weave. Impregnation time approximately 3 minutes and then allow tray is covered. Should not be preferentially absorbed by the fiber being treated. However it is recommended that a standard swatch be calibrated so that the actual desired degree of mercerization can be assured. Generally the range of twist factor is 2.2-3.0. Instead of 45â50 seconds as with cold mercerizing, the same effect can be obtained in only 25â30 seconds with hot mercerizing. 13-15% caustic concentration is applied when dye absorbency is important considered. Solutions of sodium hydroxide in the concentration range 16-19 %(wt/vol) appear to be more critical in that a small variation in the concentration causes considerable changes in the properties (moisture regain and BAN) of the mercerized cotton. water Article Nitrogen Removal for Liquid-Ammonia Mercerization Wastewater via Partial Nitritation/Anammox Based on Zeolite Sequencing Batch Reactor Lei Zheng 1,2, Yongxing Chen 1,2, Songwei Zhou 1,3, Yuchen Chen 3,4, Xingxing Wang 1,3, Xiaojun Wang 1,2,3, Lijuan Zhang 5 and Zhenguo Chen 1,2,3,5,* 1 School of Environment and Energy, South China University of … The processes of burning and desizing were done with burning-desizing machine in which a multifunctional burning machine is combined with a tub where the fabric is made to absorb the desizing solution. Increase transparency and reduce surface roughness. To summarize the benefits of hot mercerization: Essentials mercerization involves treating of cotton material with strong NaOH solution and washing it off from the material. recovery of caustic is some easier as impurities to some extent are removed by In this condition the cloth is immersed in the caustic bath with the result that only the open figures are mercerized, the protected portions remaining plain cotton. Not until the later eighties did mercerization become practical, and then for two reasons. In addition, the same results can be obtained for knitted products in the shape of a tube through special equipment. The fabric enters the washing unit (of chain type of mercerizing machine) with sodium hydroxide solution of 55Â° Tw strength. The axial ratio decrease when a cotton Mercerization details of these fabrics were given in Table 5. When the fiber swells, its volume undergoes considerable changes; at maximum water absorption, the cross section of cotton fiber is increased by 40 to 50% with inconsiderable increase in length (about 1 to 2%). The angle of reflection will be 45°, only if the Fig 11: Cellulose, the polymer of cotton, with a degree of polymerisation, About 5000 cellubiose units (i. e. n=5000). Dye absorption increases with the increasing caustic soda concentration up to 13%. Mercerization A third process often used with cotton fibers is mercerization, which changes the physical structure of the cotton fiber and thereby its … The heat that emerges during the reaction prevents swelling and therefore, float is cooled in order to achieve the best mercerization effect. Most commonly used concentration is 21-22%. Then the fabric is dried washing in cold water. The process lye is continually circulated and the temperature and concentration monitored. The yarn of hank form is placed on the guide rollers whilst they are close together. Mercerization gives cotton woven cloth a silky luster, and is the foundation of many improved and beautiful finishes. De Boer JJ, Borsten H (1962) An Empirical Relation for the Degree of Penetration of a Mercerization Solution into a Cotton Yarn. While fabrics mercerized with 15-30% solution showed higher degree of mercerization, dye absorption, and fabric strength and elongation than the unmercerized fabric. Desized, scoured and bleached cotton fabrics are … The 2. The liquor is usually heated by closed steam coils. place due to internal swelling. that is the minimum. Mercerizing of cotton is done in three basic stages of materials. The finishing operations performed on weaving fabrics include all the operations carried out to provide a fabric with those properties that the customer desires after the fabrics leave the textile factories. Luster is obtained through the use of tension; and. It was obtained that shrinkage values on warp direction were greater than those of weft. Fabrics mercerized with 10% solution showed same degree of mercerization as the unmercerized fabric but they obtained better dye absorption ability and higher fabric strength and elongation. Producing crepe effects by mercerization.-The principle of mercerization is sometimes employed to secure crepe effects in union goods, the mercerization attacking only one class of fibers or yarns, as for example the cotton threads introduced at regular intervals in a woolen structure. mercerization process involved in wet processing of textiles textiles Mercerization is the treatment of cotton yarns, fabrics and knit goods with cold, strong caustic soda liquor under tension. Temperature of the mercerization solution. Peroxide bleaching offers distinct advantages beyond good whiteness, as it is economical and flexible to use. However the P value of dobby weaves fabric appeared to be 0.190, which is higher than 0.050 in the process time period interaction, so process time period interaction does not have a statistically significant effect on the resistance to shrinkage of dobby weave fabric. The Advantages of Cotton. Solid colors and intense, resistant to washing, rubbing, light, even after being washed several times. A description of the process was quickly rushed to the patent offices of all countries, and mercerized cotton, glossy, smooth, and strong, became a big factor in commerce within a few years. Mercerization Conditions and Characterized by NIR FT Raman Spectroscopy in Combination with Multivariate Analytical Methods Heléne Almlöf Ambjörnsson,a,* Karla Schenzel,b and Ulf Germgård a Carboxymethyl cellulose (CMC) is produced commercially in a two-stage process consisting of a mercerization stage followed by an etherification stage. THE REACTIONS THAT TAKES PLACE IN MERCERIZATION: Since concentrated sodium hydroxide (operational solution that includes chemicals) is used in mercerization process, the reactions that take place with the cellulose fibers are intermolecular reactions. Fabric Mercerising Machines: There are three types of fabric mercerising machines: 1. As a result mercerizing will be better and luster increases.
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