Vol.Indian 21,Journal June 1996, of Fibrepp. 122-126& TextileResearch '

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A critical appraisal of pilling on worsted fabric

I C Sharma,K N Chatterjee,A Mukhopadhyay& A V Kumar The TechnologicalInstitute of Textileand Sciences, Bhiwaru 125 021, India Received15 May 1995; accepted 7 August 1995 The effect of blend composition,linear density and twist factor of polyester-woolblended on the pilling tendencyof polyesterworsted fabrics having the samenominal cover factor has been stud- ied over different test revolutions. It is observed that the incidenceof pills increaseswith increasein polyester content, finenessof weft thread and decreasein twist factor. At higher test revolutions, the polyester content increasesin the pill with decreasein number of bigger pills. As th,eweft count be- . comes finer, bigger pills graduallydecrease and mediumand small pills show an increasingtrend with ~ increasein testrevolutions for all the blends.

Keywords:Linear density,Pilling, Polyester-woolyarn, Polyesterworsted fabric, Twist factor

1 Introduction were made from yams having different blend ra- Pill formation is one of the appearance defects tio, linear density and twist factor, and spun on in cloth which brings down the quality of the worsted system of ~pinning. Table 1 shows the cloths and does not satisfy consumer preference. specifications of yams used and Table 2 shows Several researchers have studied the effect of var- the specifications of prepared fabric samples. ious fibre, yam and fabric construction parame- AIl the fabrics were treated with boiling water ters on pilling propensity of woven material. It for 5 min under tension and then with steam for was resported1 that in blended fabric made from 15 min under pressure. These fabrics, after load- synthetic and .. fibres, the wool fibres migrate ing, were conditioned iq an atmosphere of 20 ::!: -.. towards the outsid-e of the yam and thus remain 2 °C and 65 ::!: 2 % RH. mostly on the surface of the fabric. Wool fibres first form pills which quickly wear off. After the 2.2 Methods surface of wool fibres pill off or shed off, the syn- Pilling test of the fabric samples was carried out thetic fibres are exposed and these start to form on ICI pill box tester4 (Foricom & Co.). Fifteen pills which is reflected by the continuous increase pieces from each fabric sample were tested for in pilling. Vaidya2 observed that very effective pilling resistance. The number of pills were ob- pilling control can be achieved by using the finest served at three different revolutions, viz. 10,000, count yam; not only is the number of twist per 18,000 and 26,000. The number of pills on the inch large for given twist factor but the number of fabric surface in each specimen were counted and theyam same intersections cover factor per isunit maintained. area is also This large helps when to thepills/17 mean in2 of of 15 thespecimens fabric. was To measureexpressed the as no. blend of ~ decrease pilling. Doyle3 stated that the pilling composition, IS:3416-1966 and IS:2006-1978 tendency decreases with an increase.in twist coef- were followed. Pills in the fabric were evaluated ficient. There is, however, a maximum twist be- by projectina microscope and classified according yond which pilling is not reduced. This maximum to average pill diameter as big (3-4.5 mm). medi- isods4-6 seldomfor reachedevaluating in pills practice. have A been number proposed of meth- by 'um(1.5-3 mm)and small. « 1.5 mm).

different research workers. The present work was .. 'carried out on polyester worsted fabrics having 3 Results and DIscussion same nominal cover factor and weft materials of different counts, twist factors and blend composi- 3.1 ~ffectof Blend Compo~iti.on . tions. Fig 1 shows that pilling tendency of the fabnc j increases over different revolutions with increase I 2 Materials and Methods in the polyester content of the blend which is in ! 2.1 Materials agreement with the observation made by Gintis et Fifteen plain weave grey polyester-wool fabrics at:. Pills also increase with the increase in num- ',,"""' '" f"..,~" '.c',j,

--- SHARMA et al.:.POLYESTERWORSTED FABRIC 123

Table I-Fibre and yam specifications .' Group Nominal Blend Fibre specification Final Actual yam composition nominal twists/cm count (P:W) fulyester Wool twist factor 38:62 I 50/2 tex 55:45 3 den,89 mm 22 14m,75 mm 42.4 6.0 70:30 38:62 II 40/2 tex .55:45 3 den,89 mm 22 14m,75 mm 42.4 6.7 70:30 38:62 III 33.3/2 tex 55:45 2.5 den,89 mm 20 14m,75 mm 42.4 7.3 70:30 38:62 ~ IV 33.3/2 tex 55'!45 2.5 den,89 mm 20 14m!75 mm 45.6 7.9 70:30 38:62 V 33.3/2 tex 55:45 2.5 den,89 mm 20 14m,75 mm 38.7 6.7 70:30 P -fulyester; W -Wool

Table 2-Fabric specifications Table3-Chemical analysisof pills [Warpblend composition(P:W), 55/45; Warpcount, 40/2 tex; [Warpblend comp.osition(P/W), 55/45; Warpcount, 40/2 tex] and Weave,plain} Group Blenda Percentageof polyesterin pills Weftcount, Weftblend Ends/cm Picks/cm at the revolutionsof tex composition Norninai Nominal . (Twist factor) (P:W) (actual) (actual) 10,000 18,000 26,000 ..50/2 38:62 I 38/62 24.39 34.71 24.52 (42.4) 55:45 20(23) 18(20) (50/2 tex weft, 55/45 30.00 48.95 52.26 70:30 42.4TF) 70/30 29.46 52.10 60.92 40/2 38:62 n 38/62 30.76 23.82 29.00. (42.4) 55:45 20(23) 21(22) (40/2 tex weft, 55/45 34.48 39.20 48.00 70:30 42.4 T F) 70/30 39.65 44.93 59.98 33.3n 38:62 III 38/62 30.86 26.54 31.35 (42.4) 55:45 20(23) 23(24) (33.3/2 tex weft, 55/45 36.21 40.98 51.00 70:30 42.4 T F) 70/30 40.00 48.70 60.27 33.3/2 38:62 IV 38/62 28.00 25.00 30.33 (45.6) 55:45 20(23) 23(24) (33.3/2 tex weft, 55/45 31.25 33.84 46.52 70:30 45.6 T F) 70/30 24.44 32.90 52.00 33.3/2 38:62 V 38/62 39.72 34.00 42.00 ',.,.. (38.7) 55:45 20(23) 23(24) (33.3/2 tex weft, 55/45 45.00 46.00 52.00 .70:30 38.7 T F) 70/30 48.00 52.05 61.32 P-fulyester; W- Wool aWeftblend composition(P/W)

her of test revolution. Table 3 shows that as revo- Table 5 shows that in almost all the cases with lutions increase the percentage of polyester fibres the increase in polyester content, bigger pills dec- in pills is increased, specially in polyester-pch rease whereas the medium and small pills gradu- blend. However, no such trend is observed in ally increase for all the counts and at all the revo- wool-rich blend, which may be due to continuous lutions. The above observation may be owing to pill formation and pill wear off predomin~ted by bigger piUs which are formed mainly by wool fi- ~' wool fibres. It is observed from the Table 4 that bres whereas the medium and small pills are as the polyester content increases in the blend, dominated by polyester fibres. the number of hairs (all types) decreases but the tendency of pilling increases. Thus, it may be con- 3.2 Effect of Count cluded that fibre properties predominate over the Fig 2 shows that pilling increases as the yam number of hairs in the constituent yam. becomes finer. This may be attributed to the fact I 124 INDIAN J. FIBRE TEXT. RES.,JUNE 1996

60. 50 10,000 revolutions 10,000 revolutions 5 loO --f

4 30

3 2

2 10 1 0 1000 100 18,000 revolutions 18,000 revolutions No 80 c N, 8 ~ .: -60 r-. -~ -:::"6 .!!!. ~\""~ =1/1 ==D- loo oc.4 - -00 ' 2 ° 0 0 Z z 2 0 0 100 26,000 revolutions

100 26,000 revolutions 8

8 6

6 loO

4 200

2 50/2 loO/2 33.3/2 0 Weft Count, tex

38/62 55/45 70/30 Fig.2-Effect of count on pilling propensity at different test Blend composition(P/W) revolutions [Blend composition (P/W): -8- 38/62, -~- 55/45, and -x -70/30; Twist factor, 42.4] Fig. I-Effect of blend on pilling propensity at different test revolutions [Weft count, tex (TF): -0- 50/2 (42.4), -/.- 40/2 (42.4), -~- 33,3/2 (42.4), -0- 33.3/2 (45.6), and -x -33.3/2 ()8.7)] Table 4 shows that although the yam hairiness that as compared to coarser yam, finer yams of is less in case of finer yam of same twist factor T same blend (atio have greater proportion of pol- and blend ratio, but the pilling propensityis high- yester fibres on the surface of yam due to the er in case of fabric with thinner weft yam. This higher bending modulus of polyester fibres. As may be attributed to the fact that the properties the anchorageproperty of the pills formed mainly of. fibres predominate over the. effect of no. of by polyester fibre is more, the fabric with finer hairs. weft yanis exhibited relatively higher pills. The From Table 5, it is observed that in 'almost all above observation is in contradiction with the the casesas the count becomesfiner, bigger pills earlier findings where it was stated that due to gradually decrease and the medium and s~ greater number of crossoverpoints in case of fin- pills show an increasingtrend in all the blends at er yam, less pill formation will take place, but different revolutions. This may be attributed to / here the effect of fibre propeJriesis predommat- the fact that in ~e case of fabric with the finer ing over the effectof numberof crossoverpoints. yam, there is relatively lesser proportion of wool In case of 33.3/2 tex, finer fibers are used fibres on the surface of yam. With the increasein (usuaJcommercial pracnce) which aiso leads to revolutions, the bigger pills gradually decrease' greaterpill formation. whereasmedium and smallpills increase. ~ \' SHARMA eta/.: POLYESTERWORSTED FABRIC 125

Table 4- Yam hairiness ; )~- [Warpblend composition(P/W), 55/45; Warp count,40/2 tex) Weft Group blend No. of protruding fibres/in. lengthof yam Total no. of composition protruding (P/W) < 1.5mm 1.5 mm-J.O mm > 3.0 mm fibres/in. I 38/62 83 37 20 140 (50/2 tex weft, 55/45 79 36 17 132 42.4 T F) 70/30 61 36 15 112 II 38/62 78 37 20 135 (40/2texweft, 55/45 72 35 19 126 42.4 TF) 70/30 59 35 16 110 III 38/62 75 38 19 132 (33.3/2 tex weft, 55/45 68 37 19 124 ..42.4 T F) 70/30 61 35 17 113 rv 38/62 74 35 14 123 (33;3/2 tex weft, 55/45 67 33 14 114 45.6TF) 70/30 59 30 11 100 V 38/62 17 38 21 135 (33;3/2 tex weft, 55/45 69 38 20 127 38.7TF) 70/30 63 36 18 117

Table 5-Size analY.sisof pills [Warpblend composition(P/W), 55/45: Warpcount, 40/2 tex) Group Weft No. of pills/ 17in2 according to pill size at the {evolutionsof blend composi- tion 10,000 18,0()0 26,000 r (P/W) B M S B M S B M S I 38/62 3.0 1.6 4.4 2.0 3.6 11.4 1.2 2.8 36.0 (50/2 tex weft, 55/45 2.8 4.0 17.2 1.6 8.9 23.6 1.0 5.0 50.0 42.4TF) 70/30 1.0 7.4 21.6 1.0 8.8 29,2 0.6 9.0 57.4 II ~8/62 1.6 2.0 16.4 1.4 4.0 34.6 1.0 8.0 39.0 (40/2 texweft, 55/45 1.0 4.2 20.8 0.9 6.0 37.1 1.0 9.0 51.0 42.4TF) 70/30 0.7 4.3 27.0 0.4 7.4 ,$0.2 0.5 10.0 58.5 III 38/62 1.2 4.4 17.4 1.0 8.4 34.6 0.5 5.6 45.9 (33.3/2texweft, 55/45 1.0 5.0 25.0 0.8 10.6 37.6 0 5.8 60.2, 42.4TF) 70/30 0.5 8.6 29.9 0.4 12.6 67.0 0 7.2 74.8 r" IV 38/62 1.0 7.4 4.6 0.6 7.4 10.0 0 7.0 19.0: ~ (33.3/2 tex weft, 55/45 0.8 8.2 12.0 0.4 14.4 19.2 0 25.0 19.0 45.6TF) 70/30 0.4 9.0 15.6 0.2 21.2 49.6 0 13.6 56.4 V 38/62 2.0 7.8 19.2 1.8 5.8 40.4 1.2 6.4 48.4 (33.3/2 tex weft, 55/45 1.5 9.0 27.5 1.2 7.6 45.2 0.9 5.6 Q3.5 38.7TF) 70/30 1.0 11.0 37.0 1.0 10.8 76.2 0.4 9.8 85.8 Pills diameter:B-Big (3-4.5 mm~ M-Medium (1.5-3 mm),and S-Smali ( < 1.5mm)

3.3 Eft'ectof Twist Factor observed that the percentage of polyester is lowerI '-' It is observed from Fig.3 that twist factor plays at higher tWist which may be due to lesser pro- an important role in pilling tendency of fabric. As portion of polyester fibre on the yarn surface as the tWist factor increases, the pilling tendency of twist factor of weft yarn increases due to tension fabrics decreases at all revolutions which is in developed in delta zone during ring . agreement with the findings of Baird et al.8. Apart from this, with increase in twist factor, From chemical analysis of pills ,Table 3) it is hairiness decreases (Table 4) which is also,respon-~ . 126 INDIAN J. FIBRE TEXT. RES.,JUNE 1996

60 10 000 I t.polyester content in all the counts and at all the .r~vo u Ions . 5 test revolutions. 4.2 The number of pills increases as the weft be- -~ 4 comes finer. No correlation has been found be- 30 tween the hairiness and the total numbeI of pills. 4.3 With increase in twist factor, the number of 2 pills decreases in all the cases. A significant corre- 1 lation has been observed between the hairiness and the total number of pills. 4.4 At the higher test revolutions, the polyester 10 content increases in the pill, specially. in the case N. 8 of polyester rich blend. ~ 4.5 The bigger pills which are initi~ly formed at ; 6 lower test revolutions (l~,OO.O) decrease ~radually, ~ = but medium and small Pills mcrease at higher test -40 ~ revolutions. 6 2 4.6 As the weft count becomes finer, the bigger Z pills gradually decrease and the medium and 0 small pills show an increasing trend with increas{ 100 26,000 revolutions in test revolutions for all the blends.

80 Acknowledgement 60 The authors wish to thank Prof. R C D Kaush. ik, Director, TITS, Bhiwani, for providing the fac. 40 ilities to carry out this work. They are also grate- ful to the management and staff of Jayashree 2 Mills, Calcutta, for preparing the samples. ---{

0 38.7 42." 45:6 Twist factor References 1 WoolScience Review, 42 (f971) 32. Fig. 3-Effect of twist factor on pilling p~opensityat different 2 VaidyaA A, Colourage24 (1977)35. test revolutions [Weft count, 33.3/2 tex; Blend composition 3 Doyle P J, J TextInst, 44 (1953)561. (P/W):-e- 38/62, -~- 55/45,'and -x -70/30] 4 Booth J E, Principles of textile testing (Newnes-Butter- worths,London); 1968,312. sible for less no. of pills with increase in twist fac- 5 Naik ~ .& Lo~z-Amo F, in Blended (The Textilf tor. Table 5 shows that as the twist factor in- AssocIatIon.IndIa), 19~1,181-202. all f ill h ed .6 RamgulamR B, Amirbayat J & Porat I, J Text Inst, 84 creases, types 0 p s ow r uction. (1993)221. 7 GintisAJ, TextRecorder, 1 (1961)58. y- 4 Conclusions 8 Baird M E, Hatfield P & Morris G J, J Text Inst, 4; 4.1 Pills generally increase with the increase in (1956)TI81.

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