Indian JOurnJI of Textile Research

Vol. 10, December 1985, Pp. 166-170

Effect of Texturing Heater Temperature onYarn and Fabric Characteristics

.~

I C SHARMA, NARENDER GUPTA, S K RANJAN, SANJAY SUNEJA and SUNIL MEHTA

The Technological Institute of Textiles, Bhiwani 125022, India

Received 5 June 1984; revised and accepted 29 May 1985

The ieffect of texturing heater temperature in simultaneous draw-texturing of polyester on both yarn and fabriccharacteristics has been studied. Five yarn samples were prepared at five different heater temperatures, viz. 185, 195,205, 215and 225°C, and the fabric samples were produced by using these yarns in weft. With increase in heater temperature, the yarntenacity increased up to 205°C and then decreased. Heberlein crimp contraction had a direct relationship with temperature andso had the fabric width shrinkage. The flexural rigidity of the fabric decreased with increase in temperature up to 215°C andthen increased while the crease recovery angle decreased warp-wise and increased weft-wise with increase in temperature. The

dye upake of the fabric decreased with increase in heater temperature up to 205°C and then increa~

Keywords: Draw-texturing. Fabric characteristics, Polyester, Yarn characteristics

Although some workl -4 has been done on theproperties (i)fpolyester yarns produced by the draw­texturing process, not much of quantitativeinformation is available on the properties of the fabricproduced by using these yarns in weft. This paper isaimed at studying the effect of texturing heatertemperature on yarn properties and the physical andmechanical properties of fabrics produced from theseyarns, such as dimensional changes in processing, airpermeability, tensile strength, flexural rigidity, creaserecovery angle, and dye uptake.

Materials and MethodsFive yarh samples of 150 nominal denier were

prepared f~om the polyester multifilament partiallyoriented yarns (POY) with the titer denier of 230/33filaments supplied by Nirlon Synthetics and ChemicalsCo. Ltd, Goregaon, by draw-texturing the yarns at fivedifferent heater temperatures, viz. 185, 195,205,215and 225°C, on a LM-FTF 440 double-heater texturingmachine.

Using these five yarns in weft, five fabric sampleswere prepared keeping a warp count of 2/40s (PIV48: 52) and ends per inch constant at 104. The weaveused was 2(3 steep twill with a move number of 2upwards, the picks per inch being kept constant at 88.

Before tekting, all the samples were conditioned instandard atmosphere (RH 65%;27 ± 2°C)for 48 h. Thefollowing te.stmethods were used to determine the yarnand fabric characteristics.

Yarn Tests

Measurement ()lyarn denier-Samples of 9 m longyarn were t~ken under a constant tension of 0.5 g/texand weigher on a Mettler electronic balance.

166

Wt of 9 m long textured yarn under 0.5 g/tex tension = X mgWt of 9000 m long textured yarn under 0.5 g/tex tension

9000 x Xmg9

= 9000 x X/9 x 1000 g

Denier of yarn =X

Breaking load and breaking elongation- Thebreaking load of the yarn and elongation weremeasured on a· Goodbrand's single yarn strengthtester. The rate of traverse was 12 inch/min and thespecimen length used was 24 inch.

Heberlein crimp contraction test-Five skeins of 8 mlength were prepared under a pretension of0.1 g/denier and heated in water at 95°C with 0.27%owm. Wetting agent was added and retained for 30s,and the skeins were removed from water, cooled andhung on board. An appropriate load of 0.2 g/denierwas applied and the length (LI) of the skein wasmeasured after one minute of loading. After removingthe load, the skeins were kept in an oven at 50-60°C for30 min in slack condition. An appropriate load of0.002 g/denier was applied after the skeins wereconditioned for an hour. The length (Lz) was measuredafter one minute of loading.

HCC % = (LI -Lz) x 100o LI

Fabric Tests

Threads per inch-The ends and picks per inch weredetermined by a standard one-inch counting glass.

Fabric weight-This was determined (ounces persquare yard) with a quardant balance.

Percentage shrinkage-Before finishing the fabric,marks were put on it at a distance of 10inch in both

. ';;-

I~II 11II!I1R 1"-'1

SHARMA et al.: EFFECT OF TEXTURING HEATER TEMPERATURE ON YARN AND FABRIC

Table I-Breaking Strength,Tenacity,Elongationand HCC of Yarns Textured at DifferentHeater Temperatures

Yarn

TexturingTexBreakingTenacityElongationHCC

sample

heater strengthgftex%%No.

temp. g°C

1

18517.22768.5444.6425.0041.0

2

19517.33797.3445.9923.6542.5

3

20517.22822.1547.4321.6643.7

4

21517.11773.9045.2717.8344.8

5

22517.11722.9242.2117.1645.1

warp and weft directions with an unwashable ink.After finishing, the extraction of fabric was noted.

Air permeability-This was tested on a METEFEMtype AIL-2/FF-121 (Budapest) air permeability tester.In this tester, air is drawn by a ventilator through the&pecimenin the apparatus and the pressure differencebetween the two sides of the specimen is indicated bythe monometer. The volume of air passing through theclamped surface of specimen at the pressure differenceof the monometer is measured in litres per hour by therotometer.

q x m3 min -1 m -2Then, cp x mm of water column - 6 x

where cp is the volume of air in m3min -1 m -2; q, the airvolume flowing through the cross-section of thespecimen in litres!h; andf, the test cross-section in m2•

Tensile strength-This was measured on a Germantensile strength tester in which revelled strips, each of11 x 2.5 in. were taken and the strength was tested on 7in. gauge length by gripping 2 in. length in each jaw.Threads of 0.25 in. were revelled from both the sidesand hence the remaining width was 2 in.

Bending stiffness andflexural rigidity-This test wascarried out on a Shirley stiffness tester. A rectangularstrip of fabric, which is supported on a horizontalplatform, is traversed in the direction of its length sothat the increasing part overhangs and bends downunder its own weight. When the tip of the ~pecimen hasreached a plane, which is inclined at an angle of 41.sowith the horizontal, the overhanging length is equal totwice the bending length of the specimen.

The flexural rigidity was obtained from the bendinglength and the mass per unit area of the fabric.

Flexural rigidity of the fabric (g-cm)=(bending length, cm)3 x (fabric weight, mg/cm)

Crease reeovery-This was tested on a Shirley creaserecovery tester. A rectangular specimen of2 x 1in. wasfolded and subjected to loading of 2 kg for 3 min; it wasthen allowed to recover for the same period and thecrease recovery angle was measured.

Dye uptake-The fabric samples were disperse-dyedin HT HP dyeing machines using Chemelene Scartlet-

55

>('"

01 5,0>f-t:i4t5 L•. 5f-za:4>

185 195 205 21'i 225HEATER TEMPERATURE, C

Fig. I-Effect of heater temperature on yarn tenacity

28

0: 24zQf­<l:

l') 20zo--'w

16~ I I I I185 195 205 215 225

HEATER TEMPERATURE~C

Fig. 2-Effect of heater temperature on yarn elongation

RR disperse dye and a dispersing ngcnt-Cetamol WS(1 gjlitre). For testing dye uptake, first a standard curveof optical density versus dye concentration was plottedby measuring optical clarity on a photocolorimeter(Toshniwal). Then, the optical density of exhaustliquor for different samples was observed on thephotocolorimeter after diluting all the exhaust liquorsto the same extent. From the standard curve, dyeconcentration in exhaust liquor was interpolatedcorresponding to its optical density and this was takenas a relative index of dye uptake.

Results and Discussion

Strength and elongation of yarn-Data on thestrength and elongation of yarn (Table 1;Figs 1and 2)

167

INDIAN 1. TEXT. RES., VOL. 10, DECEMBER 1985

indicate that the yarn tenacity increases with increasein heater temperature up to 20SoC and then decreases,whereas the elongation of the yarn decreases.

These results may be explained as follows. As theyarn enters.the first heater zone, it is acted upon by twomechanical forces, namely tensile forces due to ap­plication of draw and torsional forces due to twisting,which will cause a change in crystallite orientation.The tensile forces will tend to align the crystallites inthe direction of the fibre axis, while the torsional forceswill result in disorientation of crystallites.

The effect of these forces on crystallite orientationdepends oJ the texturing heater temperature, becausethe mobility of the molecules in the filament will varywith the temperature. The higher the temperature, themore mobile are the molecules and the more quickly dothey move to take up new positions.

So up to 20SoC, tensile forces may dominate over thetorsional forces, resulting in better crystalliteorientation and increased te'nacity of the filaments.Above this temperature the torsional forces causedisorientattion. This is because the molecules are

helically oriented and also the polymer chainbreakages may occur due to the application of hightensile forces at such a high temperature, resulting in areduction in tenacity.

The elongation decreases because of highermolecular- orientation and at higher temperature itdrops significantly, probably due to elongation ofhelices. Further, the study reveals that under therunning conditions giving contact times of about0.66 s, texturing at temperatures lower than 20SOCmaytake place but not to the extent of permanent setting.If setting to the permanent stage had taken place thereshould have been no higher elongation as in samples 3and 4. At I8SoC, the elongation is high, implying thatthe texturing has nQt become permanent.

Heberlein crimp contraction-Data on HCC%(Table 1; Fig. 3) show that with increase in heatertemperature there is increase in HCC%. This finding isin agreement with that of Weindorfer and Egbers1,who found that with increase in heater temperature,molecules are in a mobile state and so deformations arepermanently set, which give rise to better crimpstability. Thus, because of better crimp stability andhigher crimp frequency, H CC% increases with increasein heater temperature.

Crimp and dimensional change-Data on weft crimpand weft-wise fabric shrinkage (Table 2; Fig. 4) showthat with increase in heater temperature, the yarncrimp in weft direction increases and so the fabricwidth shrinkage.

Table 2- Threads/em, Crimp, Dimensional Change and Weight of Fabrics. >-

zQf­U« 44a:f-zoUQ.

~ 42exuzwci 40w(!)WI

o;;

Fabric TexturingFinished% Crimpsample

heaterthreads/cmNo.

temp. WarpWeftCc

WarpWeft

1

18544.036.211.117.052

19544.536.611.507.253

20545.336.211.257.504

21545.736.211.258.335

22546.935.011.008.75

46

\ 185 195 205 215 225

HEATER TEMPERATURE ,oC

Dimensional change Fabric

weightWarp

Weftg/m2

shrinkageshrinkage

%%

6.15

8.24226.306.25

8.50230.516.20

8.66232.576.15

8.83234.286.20

8.90234.97

;;Il~Wl::>

~ g·OzexI 8,8<Il

;: 8'6Cl

3: 84<,,!a:00 8'2<l:LL

41 42 43 44 45

HEBERLEIN CRIMP CONTRACTION,"Io

Fig. 4-Relationship between Heberlein crimp contraction andFig. ,-Effect of heater temperature on Heberlein crimp contraction fabric width shrinkage

168

SHARMA et al.: EFFECT OF TEXTURING HEATER TEMPERATURE ON YARN AND FABRIC

The increase in yam crimp can be explained on thebasis of increase in HCC% with increase in heatertemperature since the yarn with higher HCC% willhave higher bulk and less bending rigidity, allowing itto bend easily over the warp threads which have beenwoven into different fabrics at the same warp tension.

The relationship between HCC% and fabric widthshrinkage (Fig. 4) is linear. This is in conformity withthe findings of Chaudhary and Sengupta5 that withincrease in HCC% the fabric width shrinkageincreases. Fig. 4 shows a direct relationship betweenthe fabric width shrinkage and HCC%, from which thefollowing regression equation has been derived:F.W. =0.1557 HCC+ 1.856

This relationship depends upon a number of factorslike the type of material, denier of filaments, totalnumber of filaments, yarn cross-section, and the typeof finish applied. Further, the trend of the relationshipis similar to that observed by Chaudhary and Sengupta5but the differencein the regressionequation may be dueto the difference in the inherent properties of the yarnsused.

Air permeability-While studying the effect ofdifferent heater temperatures, it was observed thatwith increase in heater temperature for weft, the airpermeability decreases. This is due to a less porousarea available to the air because of the increased fabricshrinkage, which, in turn, is due to increase in HCC%with increase in temperature.

Tensile strength-The results of tensile strength(Table 3) show that there is no significant difference inthe warp-wise tensile strength but the weft-wise tensilestrength shows the same pattern as that of the wetyarn. This is due to the difference in the tenacity of theconstituent yarns, since the fabric tensile strength inany direction is directly dependent upon the strengthof the constituent yarns in that direction.

Flexural rigidity-Data on the flexural rigidity ofthe fabric (Table 3) show that with increase in heatertemperature for weft, the flexural rigidity of the fabric

along weft-way decreases up to 215°C and thenIncreases. As explained earlier, with increase in HCC%the bulk will increase and the bending rigidity of theyarns will be less and so the flexural rigidity of thefabric along weft-way will also be less. But in the caseof sample No.4, flexural rigidity increases, which maybe associated with the change in frictional propertiesof the textured filament yarn at higher temperatureowing to slight disorderliness of macromolecularchains. But at an temperature of 225°C, because ofmuch deterioration of molecular chains it againdecreases.

With increase in ends/in. (warp-way direction) theflexural rigidity offabric decreases because ofloweringof bending length, which is in agreement with thefinding of Morton and Hearle 7. This is probably due toincrease in fabric weight with increase in end/in. of thefinished fabric. In sample No.5, flexural rigidity againincreases, which is probably due to higher weft crimp,assisting warp yarns and restricting the degree offreedom in the fabric.

Crease recovery-Table 3 shows that with increasein heater temperature for weft the crease recoveryangle decreases warp-way and increases weft-way.Owing to increase in temperature, more and moremolecules in the filament get oriented and. it becomesstiffer, resulting in an increase of crease recovery anglewhen measured along the weft direction. Warp-waycrease recovery angle decreases owing to a slightvariation (in.crease) in ends/in. of finished fabric.Fabric weight also increases, assisting in lowering theangle of crease recovery in warp-way direction.

Dye uptake-The concentration of dye in exhaustliquor was taken as an index of dye uptake of thefabric, i.e. the greater the dye concentration in exhaustliquor the lesser is the dye uptake. Thus it is observedfrom Table 3 and Fig. 5 that the dye concentration inexhaust liquor increases from sample No.1 to 3 andthen decreases; the dye uptake decreases with increasein temperature up to 205°C and then increases, which

Table 3- Tensile Strength, Air Permeability, Flexural Rigidity, Crease Recovery Angle and Dye Uptake of Fabrics

Fabric

sampleNo.

1

2

3

4

5

Texturing Tensile strengthAirFlexural rigidityCrease reco veryDye uptakeheater

(in kg)permeability(mg-cm)angle, deg(% dye cone.

temp.

m3/min/m2 in exhaustliquor)°C

Warp-Weft- Warp-Weft-Warp-Weft-

wise

wise waywaywayway

185

127.594.554.16103.5120.1123.5122.10.042

195

129.395.252.66103.5111.1123.0128.20.052

205

129.096.051.5098.2105.2119.7138.60.058

215

126.891.350.6697.8107.4114.8143.60.054

225

126.987.550.33101.2103.5109.9144.60.044

]69

INDIAN J. TEXT. RES., VOL. 10, DECEMBER 1985

Cl:o::> o·bso..J

l­ll)::><l:Itj )'05zUzou~ 0'04o

185 195 205 215 225

HEATER TEMPERATURE 1°C

Fig. 5-Effect of heater temperature on dye concentration inexhaust liquor

has been found to be in agreement with the findings ofGupta and Gulrajani4•

The initial decrease in dye uptake with increase inheater temperature can be explained as follows. Theamorp'hou~ volume decreases owing to the formationof small c)\stals and orientation, whereas at the highertemperature the main structural changes occurbecause of melting of paracrystallites and theirrecrystallization as large and more perfect crystallites.Hence the1space for dye molecules in the amorphousregion will increase, leading to greater dye uptake.

Conclusions

(1) The yarn tenacity increases with increase in

heater temrerature from 185 to 205°C and then dropssignificantly on further increase in temperature.

(2) The elongation of the yarn decreases withincrease i~ heater temperature.

(3) Heberlein crimp contraction increases withheater temperature.

170

(4) The weft-wise fabric shrinkage increases with theuse of weft yarns textured at higher heatertemperatures and so the weight per square yard andweft crimp .

(5) The air permeability of the fabric decreases byusing the weft yarns textured at higher temperatures.

(6) The weft-wise tensile strength of the fabricsfollows a similar pattern as the tenacity of the weftyarn.

(7) With increase in heater temperature, weft-wayflexural rigidity decreases up to 215°C and thenincreases, while flexural rigidity decreases because ofincreased ends/in. of fabric during finishing.

(8) With increase in texuring heater temperature,the crease-recovery angle of fabric decreases warp-wiseand increases weft-wise.

(9) The dye uptake of the fabric decreases withincrease in texturing heater temperature up to 205°Cand then increases with increase in heater temperature.

AcknowledgementThe authors are thankful to Prof. R.C.D. Kaushik,

Director, Technological Institute of Textiles, Bhiwani,for his cooperation and help.

References

I Weindorfer Hand Egbers G, Text Res J, 45 (1975) 654.

2 Parikh B H and Nigam J K, Man-Made Text India, 22 (1979).

3 Wilson D, Text Prog, 10(3) (1978) 35.

4 Gupta V Band Gulrajani M L, Text Res J, 45 (1975) 463.

5 Chaudhary C K and Sengupta P, Man-Made Text India, 26(1983)103.

6 Textured yarn technology, Vol. I (Monsanto Publications) 1967.272-73.

7 Morton W E and HearleJ W S, Physical propertiesoftexti/efihres,(Textile Institute, London) 1975,399.

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