TECHNO-ECONOMICAL EVALUATION OF TEXTURED VISCOSE RAYON YARNS

Transcription

1 International Journal of Textile and Fashion Technology (IJTFT) ISSN Vol. 3, Issue 4, Oct 2013, TJPRC Pvt. Ltd. TECHNO-ECONOMICAL EVALUATION OF TEXTURED VISCOSE RAYON YARNS TASNIM N. SHAIKH & S. A. AGRAWAL Department of Textile Engineering, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Gujarat, India ABSTRACT Viscose rayon was developed as a man made replacement for the most favourable natural cotton fiber. It was textured by mechanical mode texturising systems, viz; air jet texturising and mechanical crimp texturising due to its non thermoplastic nature. The product yarns were verified for various structural, mechanical and texturising characteristics. Air jet yarn had shown higher bulk, loop size and loop frequency. However it lagged in terms of mechanical properties, stability of textured configuration from mechanical crimp textured yarns. Unlike air jet textured, mechanical crimp textured yarn denier was found almost identical to parent yarn. Mechanical crimp texturising has economical proficiency over air jet texturising due to obviation of cost adding factors from the process. KEYWORDS: Viscose Rayon, Pre-Twist, Configuration, Bulk, Percent Instability INTRODUCTION Viscose rayon yarn is the most preferred replacement of natural cotton fiber, possesses all the favorable features. [Rao et al. (1979), Berkeley (1966), Hearle et al. (2001), Goswami et al. (1976), Usenko (1975) and Gupta et al (1997)].Texturising of viscose rayon was never been thought of earlier by commercial players due to its non thermoplastic characteristics and low dry as well as wet strengths [Baksheev et al. (1981), Agafonova et al. (1975) and Shaikh et al. (2012)]. However, the system can offer shorter route compared to commercially adopted systems, viz; high twisting of multifilament yarn or blended spun yarn, for imparting weavability with due preservation of preferable characteristics. This ignorance is mainly attributed to the non thermoplasticity of this legendary yarn against the thermo plasticity based commercial texturising systems. However, Ivanova et al [(1971) and (1974)] texturised viscose rayon in xanthate state by multistep process. Although fascinating results are obtained, the complexity and non-economical mode of operation has not allowed this option to be get commercialized. Air jet texturising is based on pneumatic concept (mechanical mode) of texturising. The exemption of heat in these processes makes it applicable to both thermoplastic and non-thermoplastic categories of yarns. Shaikh et al [(2010) and (2011)] developed the other versatile concept, Mechanical crimp texturising, still at an experimental stage. The technological and economical efficacy of both the versatile systems was evaluated for non-thermoplastic viscose rayon multifilament yarn. EXPERIMENTAL Materials Fully drawn 117d/ 39fils. Viscose rayon multifilament yarn was used for the study. It had tenacity of 2.11 g/den and percent extension of It was textured by both the mechanical methods of texturising. Methods Air jet texturising is the well-known commercial texturising technique, need not any further introduction.

2 44 Tasnim N. Shaikh & S. A. Agrawal Mechanical Crimp Texturising technique is launched by Shaikh et al. [(2010), (2011), Shaikh (2010) and Bhattacharya S. S. et al (2010)] and still not commercialized. A comparative status for production pattern of both the mechanical techniques is shown diagrammatically in figure 1. Figure 1: Comparative Production Pattern of Mechanical Texturising Systems Courtesy Shaikh et al The selected viscose rayon yarn was texturised on the single head lab model machine of Mechanical crimp texturising at 197 tpm pre twist. Empirically derived optimum false twist (3071 tpm), delivery speed (200 m/min) and bulking zone length (25 mm) for the selected yarn on lab model machine were used. Under feed maintains constant texturising tension of gf/den (based on parent yarn linear density), at bulking zone, based on constant extension principle. [Hearle et al (1965) and Berkeley (1966)]. Demier et al (1988) has set it by change gears in the main drive. Hearle et al (1965) explains that input parent yarn tension value is kept just sufficient to keep it taught. It is varied with additive tensioner and measured with mechanical tensiometer. Winding is carried out at 5 % over feed. Air jet texturising was carried out at 500 m/min on commercially operated Air jet texturising machine AIKI Japan in dry state. Wet viscose rayon yarn was losing the strength considerably and causing frequent end down, so not opted for. Heberlain, Hemajet 311 cylindrical nozzle, jet core was used to carry out texturising at 30 % over feed with 8 Kg/cm 2 air pressure. Mechanical stretch of 5% was applied. Test Procedures Textured yarns as well as parent yarn were conditioned for 24 hours at standard atmosphere for tropical regions, viz; 65% ± 2% relative humidity and 270C ± 20C temperature before testing [Booth, J.E. (1996)]. Parent yarn, feeder yarn and textured yarns were checked for their denier [R & D Centre Calico Mills (1984)] mechanical properties [ASTM Standards D (2002)] and boiling water shrinkage [R & D Centre Calico Mills (1984)]. In addition textured yarns were tested for structural characteristics, viz; Yarn diameter, Loop / curl size & Loop/curl Frequency by Wray method [Usenko (1975) and Wray (1969)] on ERMA SCOPE projection microscope at 100x. Bulk factor [Burnip et al (1961) and Shaikh et al. (2010)] and loop/ curl instability [DuPont Technical Information Bull. (1961)] were also measured to define degree of effectiveness of texturising. RESULTS AND DISCUSSIONS Structural Characteristics The modified configurations of flat yarn on texturising had been numerically measured in terms of loop/curl size 18, 33

3 Techno-Economical Evaluation of Textured Viscose Rayon Yarns 45 and loop/curl frequency, core diameter and total diameter by optical method and were summarized in table 1. Photographs of microscopic views for mechanical crimp textured and air jet textured yarns were taken randomly, at different positions of packages. They are summarized in Figures 2(a-b). Properties Sample Table 1: Test Data Parent Yarn Air Jet Textured Textured Yarn Mechanical Crimp Texturising Total Diameter(mm) Core diameter (mm) Loop/Curl Height (mm) Loop/Curl Frequency/mm Bulk Factor (θ) Loop/Curl Instability (%) Denier 117d Boiling water shrinkage (%) 1.78 Extension F: 117 F: T: 136 T: F: 1.78 F:2.26 T: 1.18 T: 3.18 The structure of air jet yarn was composed of bundle of parallel filaments in the core of the yarn with filament loops of varying size anchored around it, along the length of yarn [figure 2(b)]. The size and frequency of the loops were much higher than the mechanical crimp textured yarn [table 1&figures 2(a-b)] at the selected texturising parameters. This had also resulted into comparatively more voluminous, loose and open structure. Bigger total diameter as well as core diameter values (table 1) obtained for air jet textured yarn substantiate the observation. Mechanical crimp textured yarn had constituent filaments with curled configuration due to false twisting. These curled constituents were locked around the core by means of real twist as well as intermingling caused due to migration of filaments on false twisting. The feeder yarn with real twist (pre twist) in its matrix had constituent filaments more tangled to yarn axis, to start with the migration on false twisting. This had lead towards increased total migration in the final yarn. The increased interchange in position from core to sheath and again back to core had increased extent of intermingling of filaments at the core. So, the yarn produced was having compactly packed core. This frequent changeover of filaments had also resulted in the formation of smaller size curls well bound around the compact core along the length of yarn. Altogether this had produced mechanical crimp textured yarn with small total diameter as well as core diameter values and bulk factor. (Table 1) Structural configuration of mechanical crimp textured yarns had gone in accordance to the classical theory of twisting for multifilament yarn. [Hearle et al (1962, 1965 and 1968), Riding (1964) and Tretoar (1965)] (a) Mechanical Crimp Textured Yarn (b) Air Jet Textured Yarn Figure 2: Photographs of Microscopical View of Textured Yarns

4 46 Tasnim N. Shaikh & S. A. Agrawal Bulk Factor (θ) The term bulk factor (θ) was defined as the ratio of the specific volume of the textured yarn to the specific volume of the parent filament yarn before texturising. [Burnip et al (1961) and Shaikh et al (2010)]The specific volume v is given by equation 1. (1) Where d is the mean yarn diameter in millimeters, l is the length of sample in millimeters, and m is the mass in milligrams. Thus for the identical test length, coarser and bigger diameter air jet texturised yarn had executed higher bulk (table 1) as per expectation. Percent Instability Highest instability value had gone in the account of air jet textured yarn. This was mainly attributed to the presence of more number of longer loops anchored in the structure. Opening of these loosely anchored loops on the application of heavy load had led it towards higher permanent extension. However, the value was well within the acceptance level of Du Pont [DuPont Technical Information Bull. (1961)]. Mechanical crimp textured yarns had shown much lower value of percent instability in comparison to air jet textured yarn. This was due to compact packing of small size curls in structure by the frequent changeover of constituent filaments [Hearle et al. (1962, 1965 and 1968), Riding (1964) and Tretoar (1965)] and binding twist (pre-twist) present in the yarn matrix. They had resisted straightening of curls under the applied heavy load. Denier Air jet textured yarn linear density was higher than its parent yarn. This was as per expectation due to over feed mode of air jet texturising [Rao (1979), Berkeley (1966), Hearle (2001), Goswami (1976) and Usenko (1975)]. On the other hand mechanical crimp textured yarn had retained almost identical fineness to that of its parent yarn (Table 1). This was due to drawing action caused on underfeeding. As constant extension mode was adopted for maintaining constant yarn tension during texturising [5% under feed]. Drawing action caused due to under feed had reduced yarn fineness to 110 d (based on ten readings average). But simultaneously parent yarn was pre twisted before entering to the bulking zone, caused contraction, added to linear density. Feeder yarn fineness value reported in table 1 had supported the argument. The feeder yarn fineness had further added by crimpiness attained during texturising [Shaikh (2010), Shaikh et al. (2010), (2011),(2012) and Bhattacharya S. S. et al (2010)]. Thereby textured yarn fineness found to be coarser than the feeder. However, the fineness value of mechanical crimp textured yarn was found almost identical to that of parent yarn (Table 1). Percent Boiling Water Shrinkage Viscose rayon has a major domain of end use in the apparel sector [Butyagin et al. (1988) and Butkova et al.(1997)] Modified configured viscose rayon will be thereby more appreciated by apparel industry. Percent boiling water shrinkage of textured yarn has a greater impact on the dimensional stability and cover of the fabric; two major aspects defining garment performance. Thereby measure of percent boiling water shrinkage for textured yarns, should be paid more attention. Air jet texturising is carried out by subjecting parent yarn to the turbulence of air in the state of overfeed. Separated filaments bent to form arc or loops; which get lock in position by their intermingling. Shortening of the length on

5 Techno-Economical Evaluation of Textured Viscose Rayon Yarns 47 loop formation develops tension in the yarn. But this tension is just enough to keep it taught [Bock (1981) and Demier et al. (1988)] since yarn/ filaments are not undergoing marginal rise in tension during bulking. Thereby they do not show tendency to shrink while treated with boiling water. Going in accordance to this basic characteristic, air jet textured yarn had shown extension of 1.18 % in the present case (Table 1). This was mainly due to the removal of loosely adhered loops on the applied load, although stabilized stretch of 5% had been given. Mechanical crimp texturising was carried out in underfeed state; develops tension at the point of feed to the bulking zone. Pre twist had further added to this tension in direct proportion to its magnitude. Yarn tension was then increased due to torsional deformation and bending deformation under gone by constituent filaments on false twisting. So, the stress present in the resultant yarn structure was quite high and prompts it to shrink on stress relaxation while treating with boiling water. [Goswami et al. (1976), Hearle et al. (2001) and Gubaidullina et al. (1972)].Test results (Table 1) substantiate the arguments. Gubaidullina et al. (1972) states the similar behavior for viscose rayon multifilament yarn, while studying influence of twist on its Physico-mechanical properties. Going in the closer resemblance with this classical theory of twist for viscose rayon yarn, percent boiling water shrinkage of feeder yarn had also shown rise with increased twist value (Table1). Mechanical Properties Mechanical properties of parent yarn, feeder yarn and textured yarns were given in table 2. Table 2: Mechanical Properties Property Parent Yarn Air Jet Textured Mechanical Crimp Tenacity (gm/den) Extension % Parent yarn was the fully drawn flat multifilament yarn, composed off all the straight filaments parallel to yarn axis. Thereby all the filaments had simultaneously shared the applied load to the yarn during tensile strength test. Thereby highest tenacity value had gone in its account as per expectation. Air jet textured yarn is the bulky yarn with well anchored loops with the compact core. Deviation of constituent filaments for the formation of loops drops textured yarn strength as compared to parent yarn. Simultaneously well bound loops with core resists their opening against the applied load and thereby results in reduced extension. [Usenko (1975), Goswami (1976), Hearle (2001) and Rao et al (1979)] Mechanical properties of air jet textured yarn had shown good agreement with this basic tendency of air jet textured yarn. However, drop in extension value was not marginal. It was mainly attributed to the presence of many long unstable loops in the structure at the selected texturising parameters [figure 2(b)]. They had allowed easy opening of loops at an applied force. Mechanical crimp textured yarn, on the contrary had retained strength almost identical to that of parent yarn apart from filament deviation from the straight path. This was due to presence of higher locking forces in the yarn matrix in the form of real twist and high degree of intermingling caused on migration of constituents. Even this yarn had shown rise in percent extension value compared to its parent. This was the out come of opening of higher number of curls [figure 2 (a)] before break on the application of load. This behaviour had gone in agreement to that observed for mechanical crimp textured polyester and nylon yarns [Shaikh (2010), Shaikh et al (2010), (2011) and (2012)]. Cost Effectiveness Product economy is mainly influenced by three attributes, viz; raw material cost, power cost and labour cost. Air jet texturising was carried out on full flange multi spindle commercial machine. So, details of all the three can be availed

6 48 Tasnim N. Shaikh & S. A. Agrawal easily. But theme of mechanical crimp texturising was worked out on the single head laboratory module. Thus absolute figures for the full-flange shop-floor machine production, viz; number of spindles, labour allocation and their wages etc.were not available. In order to nullify the effect of raw material cost air jet texturising was also done by using fully drawn multifilament yarn (FDY) instead of partially oriented yarn (POY), a normal practice. The common platform of comparison was further built up by considering spindle wise cost/kg instead of machine wise cost/kg, by assuming labour compliment identical for both. The recorded data, that was utilized for evaluation had been summarized in Table 3. Although production rate of model machine was less than half of air jet textured yarn, for the identical raw material and labour cost, mechanical crimp textured yarn found more economical. This was mainly attributed to elimination of cost adding factors, viz; compressed air from the process. CONCLUSIONS Table 3: Comparative Cost-Sheet of Textured Yarns Type of Texturising System No. Variable Air-Jet Textured Yarn Mechanical-Crimp Textured Yarn 1. Production /spindle/day (Kg) Power/spindle/Hr. (Kw/Hr.) Compressor power /spindle/hr. (Kw/Hr.) Total Power /spindle/hr. [ 2 + 3] M/c Power (Rs./Kg) Raw material cost (Rs./Kg) Other cost inclusive of Still not available as Maintenance and Repairs (Rs./Kg) Lab apparatus. Total Cost =(5 + 6) (Rs./Kg) (excluding Other cost) Viscose rayon is the non thermoplastic man made yarn. It can not be textured by commercial thermoplasticity based methods. It was effectively textured by mechanical methods, viz; air jet texturising and mechanical crimp texturising. Mechanical crimp texturising had proven superiority in term of mechanical stability of the structure, strength and percent extension properties than air jet textured yarn. However, higher bulk had gone in the account of air jet textured yarn but at the increased cost of production. Elimination of cost adding factors like compressed air, use of finer feeder yarn and higher number of spares had allowed the mechanical crimp texturising to prove its cost effectiveness. REFERENCES 1. Usenko V., 1975 processing of man-made fibers, Analysis of the twist-heat-set-untwist texturing process. Moscow: Mir Publishers, pp Berkeley Hathorne L, 1966, woven stretch and textured fabrics: Patents. New York: Interscience Publishers, pp Hearle JWS, Hollick L and Wilson DK, 2001, Yarn texturising technology: Air-jet texturing and yarns. Cambridge, England: Woodhead Publishing Limited (CRC Press), pp Goswami BC, Martindale JG and Scardino FL, 1976, Textile yarns technology, structure and applications: Structurally related performance of yarns. New York: Wiley- Interscience, pp

7 Techno-Economical Evaluation of Textured Viscose Rayon Yarns Rao, M.V.S., and Talele, A.B, 1979, A Guide to Crimping /Texturising Technology, pp MANTRA Publications. 6. Gupta V. B. and Kothari. V. K., (1997). Manufactured Fibre Technology, Chapman and Hall Publication, 2-6 Boundary Road London. 7. Shaikh T. N., Chaudhari, S. and Varma, A., September- October 2012, Viscose Rayon: A Legendary Development in Manmade Textiles, International Journal of Engineering Research and Applications (IJERA) Vol. 2, Issue 5, pp Agafonova, A. L. Glavochevskaya, R. A., Pakshver, A. B., Serebryakova Z. G. and Kuznetsova, G. I.,1975, Fibre Chemistry, The process ability of textile viscose rayon, Volume 7, Number 5, Pages Baksheev, I. P., Mogilevskii, E. M., Finger G. G. and Butyagin, P. A., Fibre Chemistry, 1981,Basic problems in scientific-technical progress in the manufacture of viscose textile fibre, Volume 13, Number 2, Pages Butyagin, P. A., Butkova, N. T., Baksheev, I. P., Malyugin Yu. Ya. and Sokolovskii, B. M.,1988, Fibre Chemistry, Promising technology in the preparation of viscose textile yarn, Volume 20, Number 3, Pages Butkova N. T. and Baksheev, I. P.,1997, Fibre Chemistry,Development of technology for production of viscose fibres and thread, Volume 29, Number 4, Pages Gubaidullina, N. Kh., 1972,Fibre Chemistry, Physiomechanical Properties And Proccessing Of Man-Made Fibres, Influence of twist on the physicomechanical properties of viscose rayon filament yarn -, Volume 10, Number 1, 61-62, DOI: /BF Ivanova, L. V., Lotarev, B. M., Shimko, I. G., Lipinskii, S. P., Merzlyakova V. I. & Usenko, V. A., 1971, Textured viscose rayon filament yarn - Chemistry And Technology Of Natural-Polymer Fibres, Fiber Chemistry, Vol. 3, 6, pp , DOI: /BF Ivanova, L. V., Mogilevskii, E. M., Shimko, I. G., Lipinskii S. P. and Merzlyakova, V. I.,1974, Formation of the bulked structure of textured viscose rayon, Fiber Chemistry, Vol.6, 6, pp Demier, A., Acar M. and Wray, G.R., 1988, Air-Jet Textured Yarns: The Effect of Process and Supply Yarn Parameters on the Properties of Textured Yarns, Textile Res.J., 58, pp Bock, G., 1981, Texturising Filament Yarns in an Air Flow-Tangling Mechanism, Int. Text. Bull. (Spinning), No.4, pp Wray. G.R., 1969, the Properties of Air-Texturising Continuous Filament Yarns, J.Text.Inst. 60, pp Shaikh, T. N. (2010). Development of an innovative method of texturising (Doctoral thesis) MSU Baroda, India Shaikh T. N. and Bhattacharya S. S., 2010, Mechanical crimp texturising: A novel concept. Textile Res J; 80(6), pp Shaikh T. N., and Bhattacharya, S. S., Nov 2011, Deriving an Empirical Formula to Determine the Optimum Level of False-Twist in Mechanically-Crimped Textured Polyester Yarn. Textile Research J., Vol. 81, 19, pp

8 50 Tasnim N. Shaikh & S. A. Agrawal 21. Bhattacharya S. S., Shaikh T. N. and Pratap A., 2010, an investigation of thermal characteristic of mechanical crimp textured polyester yarn by differential scanning calorimeter (DSC). J Am Inst Phys; 1249, pp Hearle, J.W.S., Gupta, B.S. and Merchant, V.B., April 1965, Migration of Fibers in Yarns: Part I: Characterization and Idealization of Migration Behavior, Textile Research J., 35, pp Booth, J.E., 1996, Principles of Textile Testing, Butterworth Heinemann Ltd., UK, 1996, pp. 101, R & D Centre Calico Mills, 1984, Standard for flat and textured polyester filament yarns, Synthetic Fibers, pp ASTM Standards D , Sept 2002, Standard test method for tensile properties of yarns by single-strand method. 26. DuPont Technical Information Bull., Oct 1961, Characteristics of Taslan Textured Yarns, X Burnip MS, Hearle JWS and Wray GR., 1961, the technology of the production of false twist textured yarns. J Textile Inst; 52, pp Riding, G., 1964, Filament Migration in Single Yarns, J. Textile Inst., Issue 1, 55, T9- T Tretoar, L. R. G., 1965, a Migration-Filament Theory of Yarn Properties, J. Textile Inst. 56, T359-T A) Hearle et al, (1965), Migration of Fibers in Yarns. Part IV: A Study of Migration in a Continuous-Filament Yarn. Textile Res. J., 35, pp B) Hearle et al, (1965). Migration of Fibers in Yarns. Part V: The Combination of Mechanisms of Migration, Textile Res. J., 35, pp Hearle, J. W. S. and Goswami, B. C., 1968, Migration of Fibers in Yarns. Part VI: The Correlogram Method of Analysis, Textile Res. J., 38, pp Hearle, J. W. S., Gupta, B. S. and Goswami, B. C., 1965,Migration of Fibers in Yarns. Part V: The Combination of Mechanisms of Migration, Textile Res. J., 35, pp Shaikh T.N., Bhattacharya S.S and Chudasma D. J., 2012, Effect of Raw material parameters on the performance of mechanical crimp textured yarn, IJERD, 4, pp.66-73