Nilgün Özdil, Esen Özdoğan, Effects of Enzymatic Treatment on Various Tülin Öktem Spun Fabrics

Ege University Department of Engineering Bornova-İzmir, TURKEY Abstract E-mail: [email protected] Pilling and fuzz, which were not a problem at all in previous years (especially for [email protected] [email protected] fabrics), have become a major problem recently. Fibre type, the yarn spinning system, fabric Tel/Fax: 00 90 232 3887859 type, and process play an important role in the pilling properties of fabrics.In this study, single jersey fabrics knitted with 100% combed, carded and open-end cotton were used. An enzymatic process for fuzz reduction was applied at different stages, and the effect of this on pilling, strength, weight loss and the colour differences of the fabric were tested. Previous studies on this subject were carried out with small-scale samples, and therefore do not reflect the facts exactly. For this reason, all the phases of this study were specifically carried out under common working conditions like those prevailing in industry. Key words: knitted fabrics, spinning systems, pilling, enzymes, bio-polishing.

vironment. For example, pilling is one of spin yarn also has real twist but poor fibre the major undesirable and serious prob- orientation, with fibres wrapped around lems in apparel and textile products. It the yarn core. does not cause an unsightly appearance or bad handle properties, but it has an As a consequence of the difference in the accelerating effect on the rate of fibre re- spinning methods, the yarn constructions moval from the yarn structure, and hence are different. OE yarns have a twisted materially reduces the service life [1]. core and loosely wrapped sheath with trailing loops, while ring-spun yarns are Fabric pilling is a complex phenomenon well aligned along the axis (Figure1). comprised of different stages, and it is Ring-spun yarns have good fibre orienta- influenced by several factors. Fibre type tion. As a result of this, the strength of and cross-sectional shape, yarn type and ring-spun yarns is 15-20% greater than construction, fabric type & construction that of OE spun yarns. But OE yarns and fabric finishes play an important role have lower strength and higher elasticity in the pilling properties of fabrics [2]. than the corresponding RS yarn. Due to the differences in spinning methods, RS Many researchers have reported that the yarns have approximately 20-40% higher

spinning system affects the pilling resist- hairiness than OE yarns [6,7]. ance of fabrics. The yarns produced by Pilling is a very important problem, different spinning systems have structur- principally for knitted fabrics rather al differences that are expected to impact than woven fabrics. Although knitted [ ] upon pill resistance 3-5 . The essential fabrics have many advantages such as steps of ring spinning are opening, clean- higher production rates along with lower ing, carding and drawing of the fibres and production costs, comfortable and softer spinning them into yarn with twist. So, fabric structures, the pilling problem re- ring-spun yarn has real twist and good mains an important objection because of fibre orientation. But in an open-end the slack fabric structure. spinning system, the fibres of a sliver are fed into the rotating rotor, and the twist The problem associated with fuzz can is inserted as the yarn is removed from also be eliminated in order to improve the rotor and formed into the yarn. Rotor and maintain quality during the garment’s

n Introduction The change, development and globalisa- tion of the world have brought up new notions and developments in the textile sector, in accordance with all the other sectors. The number of features expected from textile products has increased due Open-end yarn Combed yarn Carded yarn to changes in the buyers’ expectations and their awareness of quality and en- Figure 1. Photographs of ring and open-end yarns.

58 FIBRES & in Eastern Europe October / December 2003, Vol. 11, No. 4 (43) FIBRES & TEXTILES in Eastern Europe October / December 2003, Vol. 11, No. 4 (43) 59 life by removing the fuzz, by using treat- Table 1. Physical properties of yarns. ments such as singeing or by applying a surface active agent such as silicon sof- Parameter Unit Combed Carded Open-end tener to soften the surface of the fabric, or Count CV % 1.7 1.5 0.8 by enzymatic bio-polishing. As a general Twist TPI 20.50 20.90 20.80 rule, woven fabrics are singed to remove Tenacity cN/tex 14.2 13.8 9.5 protruding fibres and give the fabric a Breaking elongation % E 5.6 5.6 4.4 smooth handle and surface appearance. Variation of strength % CV 7.5 7.8 8.0 On the other hand, knitted fabrics are Unevenness % U 10.2 12.1 12.8 not normally singed or defuzzed. Singe- Thin places ( -50%) - 2 17 88 Thick places (+50%) - 19 175 142 ing involves the risk of scorching the Neps (+200%) - 32 310 36 fabric, whereas the use of surface-active Hairiness - 5.9 6.9 4.9 agents reduces the water absorbency of the fabric. They are also washed out from the fabric, which eventually makes n Experimental Investigation methods them rough again. However, enzymatic Weight loss removal of the fuzz is absolutely safe, ef- Materials After the enzymatic treatments, the weight ficient and permanent as it is carried out 100% open-end, carded and combed losses of the treated fabrics were inspected. under mild chemical and physical condi- ring-spun 20 tex (Ne 30) cotton yarns, The amount of weight losses were calcu- tions with accurate control [8,9]. lated according to the following formula: produced from the same blend, were used. The physical properties of the yarns %WL = (W1-W2)/W2 The enzyme most widely used in finish- are tabulated briefly in Table 1. In this re- where: ing processes involving cellulosic fibre is W - the weight of fabric before enzy- cellulase. This enzyme is used extensively search, single jersey fabrics knitted from 1 matic treatment, in the bio-polishing of cellulosic fabrics. the above-mentioned yarns were used. W - the weight of fabric after enzymatic Bio-polishing can be applied to the fabric 2 treatment. to remove the pills and fuzz from fabric Enzymatic processing surface, to reduce the tendency of pill- Bio-polishing process was applied to the Strength loss ing, to improve the smoothness, drape, samples along with different finishing Bursting strength tests were performed flexibility and lustre [10]. Bio-polishing steps: according to ISO 2960, appropriate to the consists of a cellulase enzyme treatment diaphragm method. The bursting strength n Enzymatic treatment after pre-treat- to give a partial hydrolysis of cotton; values in kPa (kG/cm2 ´ 10-2) and the ment. so the short fibre ends are hydrolysed, bursting heights were measured. leaving the surface of the fibres free and n Enzymatic treatment after . providing a more even look [11,12]. But n Enzymatic treatment after pre-treat- DE value it should be considered that there is also ment and also dyeing. The colour intensity values of the dyed fabrics were measured by using the Hun- a loss of strength related to the amount of The cellulase enzyme Gempil 4L Connect terLab Colour Quest II instrument. weight reduction. from the Gemsan Chemical Company was employed. The fabric samples were Pilling In this study, an enzymatic process for dyed with Reactive Blue 19 dyestuff. All The pilling resistance of the fabrics was fuzz reduction was applied to the knitted tests were carried out in mill conditions. determined using a Martindale pilling fabrics made from different kinds of spun and abrasion tester, according to ISO Enzymatic treatments were carried out in yarns at three different stages; the effect of 12945-2 [14]. We rated the samples for these process on pilling, strength & weight an industrial jet dyeing machine at 50°C 500, 1000, 2000 and 5000 revolutions loss and the colour differences of the fab- for 45 minutes in a dyebath containing respectively for three couples of the test ric were tested. 1% acidic cellulase [13]. sample at each trial.

6 6

5 5 PO 4 K0 g

g 4 n n i i t t P1 K1 a a r r 3 l

l 3 l l P2 i K2 i P P 2 P3 2 K3

1 1

0 0 500 1000 2000 5000 500 1000 2000 5000 Revolution Revolution

Figure 2. Pilling rates of fabrics knitted from combed yarn; 0 - untre- Figure 3. Pilling rates of fabrics knitted from carded yarn; 0 - untre- ated fabric, 1 - enzymatic treatment after pre-treatment, 2 - enzymatic ated fabric, 1 - enzymatic treatment after pre-treatment, 2 - enzymatic treatment after dyeing, 3 - enzymatic treatment after pre-treatment treatment after dyeing, 3 - enzymatic treatment after pre-treatment and also dyeing, P - combed, K - carded, OE - open-end. and also dyeing, P - combed, K - carded, OE - open-end.

58 FIBRES & TEXTILES in Eastern Europe October / December 2003, Vol. 11, No. 4 (43) FIBRES & TEXTILES in Eastern Europe October / December 2003, Vol. 11, No. 4 (43) 59 6

5 OE0

g 4 n

i OE1 t a r 3 l OE2 l i P 2 OE3

1

0 500 1000 2000 5000 Revolution

Figure 4. Pilling rates of fabrics knitted from open-end yarn; Figure 5. Bursting strength outcomes of fabric samples; designations designations as in Figure 2. as in Figure 2.

n Results and Discussion out causing any significant deviation. were enzymatic-treated after dyeing. The graphics also show that the twice- The reason for this is the high number Pilling performed enzymatic process gives the of process phases, the high amount of First, untreated fabrics knitted from best pilling rating outcomes. mechanical forces and the long process open-end, carded and combed yarns were period, which cause the removal of the tested for pilling. After the evaluation of Effects of enzymatic processes on fuzzes from the yarn surface. When the these results, it was observed that the strength weight loss is compared according to the pilling resistance ratings of the fabric The bio-polishing process partly hydro- yarn spinning system, the fabric from samples knitted from combed yarn and lyses the cotton, which has a negative ef- carded yarn had the highest value while the open-end yarn had the lowest. The from open-end yarns were similar to fect on fabric strength level. Fabrics from amount of weight loss that occurs after each other, and there was no significant combed yarns gave the best strength val- the double enzymatic treatment was sig- difference between them. The pilling re- ues for untreated and enzymatic treated nificantly higher. sistance of open-end yarn-based knitted in three different stages, rather than fab- fabrics and combed ring-spun yarn-based rics from carded and open-end yarns. knitted fabrics were better than the card- Effects of enzymatic processes on col- our change ed ring-spun yarn-based knitted fabrics. The fabric samples’ strength loss caused It was observed that, when the number of by enzymatic treatment after pre-treat- The colour differences (∆E) of fabrics af- turns of the Martindale Instrument was ment or dyeing processes is nearly the ter enzymatic processes at different steps increased up to 5000 t/m, both ring- and same in all type of fabrics, approximately and untreated fabrics were measured. As Figure 8 shows, the greatest colour dif- open-end yarns demonstrated higher pill- around 11%. In fabric samples enzyme- ference values were observed in the fab- ing values. treated twice after pre-treatment to- ric samples that had been enzyme-treated gether with the dyeing processes, loss in twice after pre-treatment together with When the fabric samples were tested strength is about 25 % in average, and the dyeing processes. after enzymatic treatment for pilling, fabric samples from combed yarn exhibit it was established that the best pilling a noticeably higher loss of strength. ratings came from the open-end yarn- n Analyses of Results based knitted fabric samples. It was Effects of enzymatic processes on fab- In accordance with the results of this observed that the knitted fabric samples ric weight from carded yarn had the worst pilling study, we can assert that bio-polishing tendency, while the fabric samples from After the bio-polishing process, 1-5 % enables the fuzz to be removed to a re- combed yarn were somewhere between. loss in fabric weight is an expected re- markable degree, substantially reducing However, we found that if enzymatic sult. This amount shows the efficiency of the tendency to pilling. We observed that treatment was applied two times, the the process. Weight loss of enzymatic- the worst pilling properties occurred on pilling ratings for all the fabric samples treated fabric samples after pre-treatment the carded yarn-based knitted cotton fab- were similar, approximately 5. But we was slightly higher than for those which rics which had been treated with ordinary should warn the reader of the inevitable

consequences of applying the enzymatic 35 8 7 treatment twice, namely loss of weight, 30 1 1 6 2 % strength and possible deviation in colour 25 2 % , , s s 5

s 3 s

o 20 3 o l

shade. Single jersey fabrics have been l t

h 4 t h g

15 g n rated separately in order to observe the i 3 e e r t W effects of yarn spinning systems on pill- S 10 2 Strength, % Weight loss, % ing properties. 5 1 0 0 COMBED CARDED OPEN-END COMBED CARDED OPEN-END Figures 2, 3 and 4 show that the enzy- matic treatment after pre-treatment and Figure 6. Bursting strength loss (%); Figure 7. Weight loss (%); designations as dyeing affects the pilling tendency with- designations as in Figure 2. in Figure 2.

60 FIBRES & TEXTILES in Eastern Europe October / December 2003, Vol. 11, No. 4 (43) FIBRES & TEXTILES in Eastern Europe October / December 2003, Vol. 11, No. 4 (43) 61 Figure 8. Colour any significant difference whether differences (∆E); they were pre-treated or dyed. designations as in Figure 2. n It is evident that single enzymatic treatment reduces pilling tendency, 2,5 and double enzymatic treatment re- duces it more. But the reader should 2 2 be cautioned that double enzymatic E

E 1,5 1 D Ä treatment interfaces with the weight 1 3 and the strength of fabrics severely, even beyond the acceptable limits. 0,5 n The results demonstrate that enzy- 0 matic treatment causes weight loss in COMBED CARDED OPEN-END carded yarns to the highest degree. n Twice enzymatic-treated fabric sam- ples display severe colour deviations. chemicals without enzymes. The lower the expense of basic fabric requirements It should be considered that single pilling ratings of samples from carded such as strength and weight. enzymatic treatment might also yield yarn can be attributed to the hairier struc- colour deviations. This subject merits ture of the carded yarns with fibres that The reasons for the slightly higher weight a detailed investigation. partly protrude from the yarn nucleus. loss of fabric samples enzymatically This yarn structure causes fibre fuzz, treated after pre-treatment than those af- References as the protruding fibres accumulate the ter dyeing are the high number of process abrasion forces. On the contrary, open- phases, the high amount of mechanical 1. Cooke W. D., The Influence of Fibre end yarns display less hairiness, and forces and the long process period, which Fatigue on the Pilling Cycle Part I: Fuzz Fatigue, J. Tex. Inst., 1982, No 1. combed yarns have a well-aligned long cause the removal of the fuzzes from 2. Chiweshe A., Crews P. C., Influence of yarn surface. When the weight loss is fibre structure. Consequently, the pilling Household Fabric Softeners and Laun- tendency of the fabrics knitted from those compared according to the yarn spinning dry Enzymes on Pilling and Breaking yarn types is significantly lower. system, the fabric from carded yarn has Strength, Tex. Chemist and Colourist & the highest value while that from open- American Dyestuff Reporter, September, Open-end yarn-based knitted fabrics end yarn has the lowest. The amount of 2000, Vol. 32, No 9. exhibit excellent enhancement in pilling weight loss that occurs after the double 3. Özdil N., Effect of Yarn Spinning Systems properties. But it should be noted that enzymatic treatment is significantly high- on the Pilling Resistance of Knitted Fa- the open-end yarn characteristics cause er. Because of the higher loss of weight, brics, Technology, 1/2002. 4. Alston V. P. Effects of Yarn Spinning coarser fabrics to be produced. This will the double enzymatic treatment is not System on Pill Resistance of Polyester/ interfere with the enhancement of the en- recommended for normal applications. Cotton Knit Fabrics, Tex. Res. J., 62(2), zymatic process, as bio-polishing targets 105-108,1992. finer fabrics for fashionable apparels. When the colour difference values of 5. Paek S. L., Pilling Abrasion and Tensile dyed fabrics are examined, one readily Properties of Fabrics from Open-end and We have observed that there was no notices more severe deviations in colour Ring Spun Yarns, J. Tex. Inst., 1995, No 4. significant difference between the - pill shade on the twice enzymatically treated 6. Steffes E. & Schlaforst W. Melliand-Tur- ing behaviours of the fabric samples, ir- key, 1996, 26. fabrics. This is most probably because of 7. Koç..M. E., Oğulata T., Textil Teknik, respective of whether the fabric samples the difference in light reflection together September, 1999, 88. had been pre-treated or dyed before the with yarn surface modification. This is 8. Shukla S. R., Sharma U., Kulkarni K. S., Col- enzymatic process. consistent with weight and strength loss ourage, Enzymes and Their Use in Textile in twice bio-polished fabrics. However, Processing , February 2000, 47(2), 19-24. Once applied, enzymatic treatment causes one should take into account the usage of 9. Karmakar S. R., Application of Biotech- a strength loss which falls within accept- various reactive dyestuff combinations nology in the Pre-treatment Process of Textiles Colourage, Annual 1998,75-86. able limits. But readers should be cau- for different colours in textile applica- tioned that twice-applied enzymatic treat- 10. Etters N. J., Emerging Opportunities for tions (which is particularly important for Enzyme Use in Textile, Colourage Annu- ment causes severe strength loss beyond mixed colours such as khaki and grey). al, 1998, 87-92. acceptable limits. This may be explained This may cause diverse results to be 11. Nalankilli G., Application of Enzymes in by the mechanism of bio-polishing. En- presented. Eco-friendly Wet Processing of Cotton zymes are surface-active; during the first Colourage, October 1998, 45(10), 17-19. bio-polishing process, they will most n 12. Lenting H. B. M. and Warmoeskerken M. probably act mainly on the protruding ex- Conclusions M. C. G. Guidelines to Come to Minimi- zed Tensile Strength Loss upon Cellulase cessive fibrilious surfaces, and also on the n When carded, combed and open-end Application, Journal of Biotechnology 89, outer surfaces of the yarn. If we employ yarns are considered, carded yarn- 2001, 227-232. a second bio-polishing process, enzymes based knitted fabrics and those treated 13. Gemsan Textile Auxiliaries. will react on the increased surface area, with ordinary chemicals without 14. ISO 12945-2, Determination of the Re- and they will damage the yarn sufficiently enzymes exhibited the worst pilling sistance to Pilling and Change of Appe- to cause severe strength and weight loss. properties. arance of Fabrics. Although twice bio-polishing improves n The pilling behaviour of enzymatic pilling properties, this will take place at treated fabric samples did not display Received 21.01.2003 Reviewed 06.10.2003

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