Effect of dyeing parameters on physical properties of fibers and. yarns

Transcription

1 Int. Journal of Applied Sciences and Engineering Research, Vol. 4, Issue 4, by the authors Licensee IJASER- Under Creative Commons License 3.0 Research article ISSN Effect of dyeing parameters on physical properties of fibers and yarns Hafeezullah Memon 1, Nazakat Ali Khoso 2, Samiullah Memon 3 1- Key Laboratory of the Ministry of Education advanced textile material and preparation technology, Z.S.T.U. Hangzhou, China 2- Department of Textile Engineering,BUITEMS, Quetta, Pakistan 3- Department of Textile Engineering, College of Textiles,SFDAC, Karachi, Pakistan DOI: ijaser Abstract: This research paper primarily deals with the qualitative analysis of the yarn produced at different dyeing parameters. A normal problem of the industry is also discussed and can be effectively solved by using this study, during dyeing of fibers for mélange yarn manufacturing. It was found that the mechanical properties of cotton mélange yarn manufactured by changing the dyeing parameters greatly vary, thus it is essential to optimize it. Various qualitative parameters such as spun length, short fiber index (SFI), tenacity, elongation%, yarn evenness analysis, nep count analysis and yarn hairiness have been discussed and compared by changing both parameters of reactive dyeing i.e. dyeing time and dyeing temperature. Key words: Melange yarn, waste recycling, qualitative analysis, cotton fiber, USTER, short fiber index 1. Introduction A variety of fancy yarns can be easily produced having different blends nowadays been reported by Behera et al. (1997). Gong and Wright (2002) maintained that the fancy yarns are the big classification of yarns that are being used for pleasing to the eye and have something special than conventional yarn, which was also described by Oxtoby (1987). Among fancy yarns the most of the yarns are come under the heading of Melange yarn. A. R. Moghassem (2007) mentioned that mélange yarns are well-known for their gorgeous color and look. Mélange yarns are formed either by adding different colored fibers in the blowroom, or by adding different colored carded sliver onto the draw frame. Mélange yarn offers a great variety of shades, some shades may be only 0.5% and some may even be 100%. Thilak and Saravanan (2014) propose that textile materials are being consumed by extraordinary levels at higher rates due to appearance, acceptance, and obsolescence of fast fashion. Karim et al. (2007) studied very briefly the comparison of properties of rotor spun and ring spun mélange cotton yarns found considerable more loss of mechanical properties of rotor spun than ring spun yarn. All wet treatments at any stage of textile product make significant changes into the fiber morphology and fiber physical properties. The dyeing parameter of reactive dyeing done should affect significantly on the physical properties of dyed fibers. In Mélange Yarn Industry, mostly the mixing of different shades is going to be done manually. Different weights of different colored fibers are weighed and then mixed manually. The manual mixing of the fibers results better properties of the final product as the cotton fibers after dyeing lose their strength and Short Fiber Index is increased if they are mixed automatically. Yan et al. (2015) found an exponential relationship in between entropy and bulk of yarns in theoretical deviations, *Corresponding author ( hafeezullah_m@yahoo.com) 401 Received on January 2014; Published on August, 2015

2 and higher bulk and entropy is possessed by textured yarns as compare to Classical yarns. From the literature survey, it can be assumed that there is not any research have been done in this direction. Haofei (2010) have described the dyeing systems for resistance to the physical strength loss during dyeing. Yet in practice there is certain loss particularly in dyeing the fibers. In one another research by Cao (2013) have discussed one another major problem of shade variation of mélange yarn. 2. Research methodology In this study, cotton fibers were dyed at four different times 70, 80, 90 or 100 min and three different dye fixation temperatures i.e. 50⁰C, 60⁰C or 70⁰C. Thus totally twelve samples were analyzed throughout the study. The samples are coded according to their respective dyeing times followed by A, B and C to represent 50⁰C, 60⁰C and 70⁰C respectively. All the roving bobbins were properly marked for their identification. 2.1 Materials The Pakistani cotton MNH-93 available in the Mill for routine production was used for this experiment. The cotton was inspected carefully; the average fiber staple length was determined 28.8 mm by using USTER Fibrograph 730. The fiber fineness was determined by using USTER Micronaire 775, the fiber fineness was 4.38 micrograms per inch. The trash content present in the cotton bales was 7.9%. Lutensol a non-ionic surfactants by BASF, Pakistan Ltd was used for scouring and washing-off after dye application. CI Reactive Blue 220, a sulphatoethylsulphone based reactive dye, was obtained from DyStar Pakistan. The sodium chloride and sodium carbonate were of commercial grade. 2.2 Scouring and exhaust dyeing The cotton fibers were scoured in the boiling bath, using 2.5 g/l of sodium carbonate (commercial grade) and 1 g/l Lutensol a non-ionic surfactants by BASF, Pakistan Ltd. for 40 minutes with liquor-to-fiber ratio of 20:1 and then rinsed with hot water at 60 C on same tank followed by air drying to make them ready-to-dye. Same scouring recipe and parameters were used for all samples. The fiber samples were dyed in the form of opened fibers in the form of flocks. Dyebath was prepared containing the 70 g/l of Sodium Chloride and 4% dye (on mass of fiber, o.m.f.) with liquor-to-fiber ratio of 20:1. The fibers were immersed and the temperature was raised to 40⁰C and the dyeing continued for 35, 40, 45 or 50 min (primary exhaustion phase). Then 15 g/l sodium hydroxide was introduced and the temperature was raised to the dye fixation temperature of 50⁰C, 60⁰C or 70⁰C and the dyeing was continued for a further 35, 40, 45 or 50 min. 2.3 Washing-off The washing off process carried out for the removal of un-fixed dyes and residual chemicals after fixation phase of dyeing process. The liquor ratio 30:1 was used in this project for the washing off solution, and 3 g/l Lutensol was used as a soaping agent. The sequence of washing off process was the dyed fiber rinsed with cold water for 2 min at room temperature, then with hot water for 10 min at 70⁰C, soaped with 1.5 g/l Lutensol for 20 min at 95⁰C and then rinse with hot water at 70⁰C until dye desorption stopped. Finally, the fabrics were washed with cold water and dried at room temperature. 402

3 2.4 Testing The spun length of 2.5% of the fiber samples was determined by USTER Fibrograph 730. The fiber fineness was determined by using USTER Micronaire 775 according to ASTM D USTER Tensorapid 4 was used to assess the yarn tenacity and elongation at break of all specimen according to ASTM D USTER Evenness tester 4 was used to assess the evenness parameters such as the irregularity index (U %), coefficient of variation (CV %) the number of thin places (-50%) and the number of thick places (+50%) of the specimens on the basis of standard ASTM D Moreover number of neps was also determined by same machine following same standard test method. Yarn hairiness/friction Tester Y089/6 of SDL was used to determine Yarn hairiness; it was measured according to ASTM D Results and discussion 3.1 Effect on Spun length 2.5% (mm) The effective spun length percentage was determined from all twelve samples. It can be seen that by rising temperature the effective spun length is decreased, which is further decreased by the further rising the time. This may be due to fiber breakage during the dyeing processes. This reduction in the spun length of cotton fibers; suggests mélange yarn dyers to be careful about dyeing time and dyeing temperature. The possible reason for this is the more fiber breakage in case of larger dyeing time. Spun length would be further slightly decreased when these trials would be done at the production level. The changes in spun length at various dyeing parameters are presented in figure. 1. Figure 1: Spun length after each processing step in the back process 3.2 Effect on the Short Fiber Index (SFI, %) Short Fiber Index (SFI, %) for this research was considered as the number fibers shorter than 12 mm in the different stages of spinning. Amount of short fibers present in the specimen was assessed after dyeing by changing dyeing parameters. The short fibers were produced more by rising the dyeing time as compare to the rising its temperature. The possible reason is the same; as the rising the dyeing time affected more compare to rising its temperature. Short fiber index would also be further slightly increased when these trials would be brought for production. The changes in short fiber index at various dyeing parameters are presented in figure

4 Figure 2: Spun length after each processing step in the back process 3.3 Effect on Tenacity and elongation at break of yarns In order to assess the effect of adding waste onto yarn tenacity and elongation, 20Ne Ring spun Yarn was prepared by the hank roving of 0.8 on ring spinning frame after changing the parameters of back processes. The effect of various dyeing temperature and dyeing time onto yarn tenacity and elongation is shown in figure 3 and figure 4 respectively. Tenacity and elongation at break of yarns gradually decreases by rising the dyeing temperature. It can be seen that rise in temperature results lesser tenacity and elongation at break of yarns comparing to the yarn dyed by rising dyeing time. The possible reason in difference of two results is the activation of alkali at higher temperature. Figure 3: Yarn Tenacity Figure 4: Elongation % 3.4 Effect on the Evenness Generally whenever there is decrease in effective spun length of the fibers in spinning it yields high imperfection index. Industrially termed has high value of IPI. The imperfection index depends on the parameters come under the umbrella of evenness. The evenness parameters were obtained from 20 Ne Ring Spun Yarn. The evenness parameters are the irregularity index (U %), coefficient of variation (CV %), the number of thin places (-50%) and the number of thick places (+50%) which are shown in figure 5, 6, 7 404

5 and 8 respectively. The evenness was analyzed at 1000 m of length of the all specimen. The irregularity index (U %), coefficient of variation (CV %) the number of thin places (-50%) and the number of thick places (+50%) and was increased by increasing the dyeing time and dyeing temperature passages. It can be seen that the results are worst in case of rising dyeing time. Figure 5: Irregularity index (U %) Figure 6: coefficient of variation (CV %) Figure 7: The number of thin places (-50%) Figure 8: The number of thick places (+50%) 3.5 Effect on the Number of neps In fact in mélange yarn industry neps are sometimes deliberately introduced into yarns, in case of neppy yarns. But like conventional ring spun yarns, here neps are considered as unwanted factor. It is obvious that by rising the temperature there will be increase in the neps due to thermal processing of the fibers. The number of neps was analyzed at 1000 m of length of the all specimen ring spun having 20 Ne yarn count, the results are presented in figure 9. Number of neps was gradually increased by increasing the dyeing time and dyeing temperature. It was found that for same amount of temperature if introduced for fewer time results lesser number of neps as compares to the number of neps when the same temperature was introduced for larger time. 405

6 Figure 9: Number of neps at 1000 m of length 3.6 Effect on Yarn hairiness The yarn hairiness at various dyeing parameters is presented in figure 10. It was determined that there is dramatically increase in hairiness by increasing the dyeing time. This hairiness is the result of shorter and coarser fibers present in the mixing, as they move to the outer surface of the yarn in the spinning triangle. Moreover, the rise in dyeing temperature affected less on the yarn hairiness as compare to the rise in dyeing time. This may be due to the more dyeing time swell the fiber structure making it in the dyeing process. Yarn Hairiness A 80 A 90 A 100 A 70 B 80 B 90 B 100 B 70 C 80 C 90 C 100 C 4. Conclusions Figure 10: Yarn Hairiness at 1000m of all the samples From the results, it can be concluded that dyeing temperature and dyeing time is required to be as less as possible. Summing up, the effective spun length of fibers became worse in case of rising dyeing temperature; it was found that effective spun length further slightly decreased by rising dyeing time. Overall rising dyeing time affected on the yarn evenness significantly than rising dyeing temperature. The hairiness was more in the samples obtained by rising dyeing time. Short Fiber Index was more in case of 406

7 increasing the dyeing temperature of dyebath, increasing dyeing time further increased Short Fiber Index. It may be amazing but it is fact that rising dyeing time did not affect significantly on the tensile properties of the mélange yarns. The tensile properties such as tenacity and elongation further became worse by increasing the dyeing temperature. Acknowledgement The authors would like to thank all technical staff and top management of the industry for their support and guidance for this project. 5. References 1. Behera, B. K., Hari, P. K., Bansal, S. and Singh, R., Effect of different blending methods and blending stages on properties of mélange yarn. Indian Journal of Fiber and Textile Research, 22, Cao Ying gang, Shen Jiajia, Chen Weiguo, 2013, Study on Tolerance of Homogeneous Effect of Cotton Melange Yarn, Advanced Textile Technology, Gong, R. H. and Wright, R. M., Fancy yarns-their manufacture and application, The Textile Institute, Cambridge England, Wood head Publishing Ltd. 4. Haofei Huang, Wei Ma, Shufen Zhang and Rongwen Lu, 2010,Optimal dyeing systems for resistance to the physical strength loss of the PLA/cotton blended fabric Journal of Applied Polymer Science, 120(2), Karim, S. K. Gharehaghaji, A. A. Tavanaie, H., A Study of the Damage Caused to Dyed Cotton Fibres and its Effects on the Properties of Rotor - and Ring - Spun Melange Yarns. FIBRES & TEXTILES in Eastern Europe July / September, 3 (62), Moghassem A. R damaging of dyed cotton fibers with direct dye in spinning processes and its effect on the properties of cotton mélange yarn. IJE Transactions B: Applications Vol. 20 (2), Oxtoby, E., Spun Yarn Technology, Revision of Thesis (Ph.D. Bradford University), Butterworth and co Publishers Ltd, First Published, Thilak Vadicherla, D. Saravanan, Textiles and Apparel Development Using Recycled and Reclaimed Fibers. Ed. Textile Science and Clothing Technology. Roadmap to Sustainable Textiles and Clothing, Woolridge C, G. D. Ward, and P. S. Phillips, et al., Life Cycle Assessment for Reuse/Recycling of Donated Waste Textiles Compared to Use of Virgin Material: A UK Energy Saving Perspective. Resources, conservation and recycling. 46(1), Yan Jiang, Bugao Xu & Shanyuan Wang, Entropy and bulk of yarns. The Journal of The Textile Institute, 106 (2),