Indian Jo urnal of Fibre & Textile Research Vol. 29, September 2004, pp. 278-282

Polyester textured yarn fabricated spun-like filament by rotor twister

J H Lin", C H Chang & H C Chen Laboratory of Fiber Appl ica tion and Manu fac turi ng,

Graduate Institute of Textile Engineering, Feng Chia University, Ta ichung 40724, Taiwan

and

CW Lou

Insti tute o f Biomed ical Engineering and Materi al Science/General Ed ucatio n Cen ter, C hungtai Institute of Health Sc iences and Technology, Taichung 406, Taiwan

Received 23 l illie 2003; accepted / 8 Septelllber 2003

A novel rotor twister has been used to fabricate a spun-li ke fi lament ya rn usi ng a d raw-tex tu red yarn (DTY) as core ya rn and a partially orie nted yarn (POY) as wrapping yarn. During twisting. the core yarn passes th rough a pa ir of grinding wheels to cause ha iriness. The e ffec ts o f rotor speed, tw is t multiplier, number of grind ing wheels and counts o f DTY on tenac ity, elongation and hairiness have been studied . It is observed th at the dec rease in the number of gri nd ing wheels increases the hairiness but dec reases the tenac ity and e longat ion. The twist multi p li er a ffec ts ne ither the tenaci ty nor the e longati on but the increase in twist multiplie r increases the hairiness. The increase in rotor speed increases the lenac ity and e lo nga ti on but dec reases the hairiness. W ith a twist multi plier o f 1.4, ro tor speed o f 8000 rpm and gri nd ing wheels of (60# + 120#), the fil ament yarn excellently imita tes spun yarn .

Keywords: Polyester ya rn , Rotor tw ister, Spun-li ke fi lament ya rn , Yarn hairiness

IPC Code: IntCI.? D02G 3/22, DOIH 7/00, DOID 5/00

1 Introduction Synthetic continuous fil ament yarns are normally

textured before being used in processes such as weav ing or knitting. Conventi onal texturing aims to impart texture to the regularly packed, flat filament yarn to increase the comfort and aes theti c appeal of the fini shed produd -5.

Three methods are currently adopted til the production of folded yarns conventi onal ring twi sting, two-fo r-one twi sting and stage twisting. Several studies on the development of twi sting machines have already been reported6

-s. Although the ring twi ster and

the two-fo r-one twi ster have been ava il able fo r many years, their producti vity is still limited owing to thei r construction and the twi sting tension that can be appli ed. The physical properties of the plied yarns produced by two-far-one twi ster are generally poorer than those of the yarns obtained using the ring twister.

aTo whom all the correspondence should be addressed. Phone: 245 18661 ; Fax: +886-4-2451 8672; E-mail: jhlin @fcu .edu .tw

False-twist textured yarns lack inter-fil ament cohesion and consequently a number of di fficul ties exi st during unwinding and fabric form ing processes. One modern technique for impart" ng such cohes ion is air interlacing of false-twist textured yarn s. Air interl ac ing depends on a nozzle to create a very turbul ent hi gh speed air fl ow.

Constructing a new rotor spinning device to enable high speed twisting and reducing twisti ng tension are the two basic considerati ons in developing thi s novel rotor twister. Many critical obstacles in using thi s novel technique have been overcome 9-11

Although textured yarn can be crimped and bul ky, it is quite dull and not very fl ex ible. The tex tured yarn is available in fewer varieties and is less llexible than staple spun yarn. The present work is aimed at producing spun-like continuous filament yarn that differs from normal textured yarn . The novel rotor twister has been used to fabricate the spun-like yarn using draw-textured yarn (DTY) as core yarn and partially oriented yarn (POY) as wrap yarn . During twisting, the core yarn passes through a pair of grinding wheel s to induce hairiness on the surface of the yarn.

LIN el at.: POLYESTER TEXTURED YARN FABRlCATED SPUN-LIKE FILAMENT BY ROTOR TWISTER 279

2 Materials and Methods

2.1 Materials The draw-textured yarns of 33.33 tex/ 96f, 66.67

tex / 160f and 100 tex / 256f polyester filament yarns were obtained commercially and used as the core yarns. The polyester (12.8 tex / 36f) partially oriented yarn was used as wrap yarn.

2.2 Mechanism of Rotor Twister The rotor twister used is shown in Fig. 1. The

tangent belt on the motor first drives the rotor spinning device of the twist wrap machine. The front side of the core yarn and the take-up roller drag the wrap yarn and the other end of the untied core yarn is held by the mechanism of tension control roller. W\:~n the wrap yarn is untied, the core yarn simultaneously passes through the middle of the rotor twister. The wrap yarn continues to wrap with the rotation of rotor twister and finally the core yarn twisting is completed. Besides, adjusting the speeds of rotor twister and take-up roller could change the amount of twist. When the rotor rotates at a constant speed steadily, a slower speed of take-up roller could lead to a greater amount of twist.

The centri fugal force produced by the fast rotation throws out the wrap yarn on the package to wrap the central filament. The rotor sleeve nut, bearing sleeve and high speed bearings are such that the wrap yarn is fixed on the packages and the weight between the wrap yarn and the motor is balanced to achieve high speed9

- 'I . An infrared device (Microtach 8400) was used to measure the rotory and take-up speeds of the machine. Additionally, the tensioning device (SHARP Limit 2000 gf) on the machine was set to control and adjust the tension of the system.

2.3 Test Method Owing to the difference in boiled water shrinkage

of both draw textured and partial oriented yarns, the hairiness appearance of grinded filaments can be set more intensely. The hairiness is caused by the friction of carborundum wheel combinations (GC 60# / 120# or GC 60# / 180#) with size of 100 mm in diameter and 50 mm in thickness. The number of emery wheels implies the surface roughness, for instance GC 60# has a rougher granular structure and GC 180#, a smoother granular structure. The DTY was passed through the grinding wheels and rubbed by them. It was then passed through the rotor twister and wrapped by the POY to form the spun-like filament yarn. During the experiment, the specification of DTY

I - Wrap yarn 2 - Rotor spinning device 3 - Tangent belt 4 - Take-up roller 5 - Tension-controlled roller 6 - Core yarn

1

3

Fig. I-Rotor twister for spun-like filament yarn

and the combination of grinding wheels were changed. The rotor twister method was used with different rotor speeds (4000, 6000, 8000, 10000 and 12000 rpm) and various twister multipliers (1.0, 1.2, 1.4, 1.6 and 1.8) respectively to spin three specifications of spun-like filament yarns (45, 80 and 115 tex). The strength of these spun-like filament yarns was tested using a tenacity instrument. The hairiness meter was used to measure hairiness numbers.

2.4 Measurement of Yarn Characteristics The tensile properties of spun-like filaments

produced by rotor twister were further measured by a tensile test instrument (TEXTECHNO) according to ASTM D 2256 standard. The hairiness (> 3 mm) of the hybrid yarn was measured by a Zweigle G565 hairiness tester I2

-14

. The appearance of yarn was observed both by an optical microscope (Olympus CH-2) and a scanning electronic microscope (JEOL JSM-5200).

3 Results and Discussion

3.1 Influence of Rotor Speed and Twist Multiplier on Strength Fig. 2 reveals that the tenacity of each spun-like

filament yarn increases with the rotor speed but does not exceed after the optimum rotors speed (8000 rpm). However, the tenacity of the spun-like filament yarn increases slightly. The tenacity of spun-like filament yarns of all the three specifications also increases with the yarn count, as the count increases the multi-filament ends.

Fig. 3 indicates that the tenacity of each spun-like filament yarn increases with the twist multiplier, but does not exceed after the optimum twist multiplier (1.4). However, the tenacity of the spun-like filament yarn increases slowly. The tenacity of all the three

280 INDIAN J. FrBRE TEXT. RES., SEPTEMBER 2004

30

25 ..- _ _ - --k - - -- - ..- - - - - - k- - - - - A.

x 1l 20

----. -- --- -. -- - -- - -.. - -_ . -_ .. --- ----. • • • • e

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..<:: 15

bb - e- 45 lex c <l) 10 b

V1 - . - 80 lex

5 -k- 11 5 lex

0 4000 6000 8000 10000 12000

Rotor speed, rpm

Fig. 2- lnfluence of rotor speed and spun-like filament yarn count on the stre ngth for twi st multiplier o f 1.4 and grinding wheels Ilumbers of 60# + 120#

30

25 -- --- --- -.. --- . -- . -- . -- . -- -.. -- - --- --. >< e e e e e <1J 20 ~ u

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r/5 10 --- Grinding wheels( 60# + 120#)

5 - . - Grinding wheels( 60# + 180#)

0 1.0 1.2 1.4 1.6 1.8

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Fig. 3-Influence of different grinding wheels and twi st multiplier on the strength for rotor speed of 8000 rpm and spun -like filament ya rn count of 80 tex.

specifications of the spun-like fil ament yarn also improves with the (60# + 180#) combination of grinding wheels. Grinding wheels with higher numbers have finer friction particles and therefore cause lighter damage and yield higher tenacity.

The tenacity of spun-like fil ament yarn is higher than that of normal textured yarn because the spun­like filament yarn is reinforced by the wrapped POY.

3_2 Influence of Rotor Speed and Twist Multiplier on the Elongation

Fig. 4 shows that the elongation of each spun-like filament yarn increases with the rotor speed. The POY provides more elongation than DTY, yielding a higher rotor speed and more POY wrapped on the DTY. However, the elongation also increases with the yarn count, because a higher yarn count indicates the presence of more filaments in a single yarn.

[~r:_~~>x -,_. _ 0_1 S_'O_IC_' X ___ l!lI_1 _I ~_"_'x_ 1(,

13. <) ){ 1~ .2 (' 1·1.71, 1·1')·1

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II

-lOOO (,()OO ~ (I()() 1(11111) 1201 111

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Fig. 4-lnfluence of rotor speed on the elo ngatio n for twist multip lier of 1.4 and grinding wheels numbers of 60# + 120#

16

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Fig. 5-lnfluence of grinding wheel s numbers and twi st mu ltipliers on the elo ngation for roto r speed o f 8000 rpm and spu n·like fi lament yarn count of 80 tex.

Fig. 5 indicates that the elongation increases gradually with the twist multiplier at a constant rotor speed and yarn count. However, the elongation values of these spun-like filament yarns are close to each other. A higher grinding wheel number (180#) indicates a smaller grinding particle. Therefore, the effect of friction decreases as grinding wheels number increases, i.e. filament ends rubbing decreases the hairi ness. The spun-like filament yarn contains more filament ends in a yarn . Thus, the elongation with grinding wheel number (180#) exceeds than that with grinding wheel number (120#).

The elongation of spun-l ike fi lament yarn is higher than that of normal textured yarn because the spun­like fi lament yarn is reinforced by the wrapped POY.

LIN el al.: POLYESTER TEXTURED YARN FABRICATED SPUN-LIKE FILAMENT BY ROTOR TWISTER 281

D Grinding wheels( 60# + 120#) 300

[ill Grinding wheels( 60# + 180#) 275

250 233

200 E ~

150 ." :r:

100

50

0 45 80 115

Spun-like filament yam count, tex

Fig. 6--Innuence of different grinding wheels numbers and various spun-like filament yarn count on the hairiness for twi st multiplier of 1.4 and rotor twi ster speed of 8000 rpm.

~-c ..!< 1 , ~ D:--:n I" D 11 5 te .\ I

2 ~ t I "51) 2·Ll 2·10 235 1"

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Fig. 7-lnnuence of spun-like fi lament yarn count and rotor speed on the hairiness for twist multiplier of 1.4 and grinding wheels numbers of 60# + 180#

3.3 Influence of Rotor Speed and Grinding Wheels Number on Hairiness

Fig. 6 reveals that the spun-like filament yarn with higher count shows a higher hairiness than the yarn with lower count, because a yarn with higher count contains more multifilament ends. Grinding wheels also affect the hairiness for all the counts. A higher grinding wheel number (180#) implies smaller grinding particles, so the friction effect declines as the grinding wheel number increases (120#). Thus, the hairiness rubbed by the grinding wheels with the higher number (180#) is less than that rubbed by the grinding wheels with lower number (120#).

Fig. 7 reveals that a spun-like filament yarn with higher count yields higher hairiness than a yarn with a lower count at each rotor speed, because a yarn with higher count has more multifilament ends than a yarn with lower count. The hairiness, however, decreases

Fig. &--(a) OM photograph (xiS) of spun-like filament yarn (4S tex) and (b) SEM photograph (x3S) of fabric made by the spun­like filament yarn

as rotor speed increases. Tt1e hairs are wrapped by the POY, corresponding to lower hairiness, because the POY is wrapped more closely around the DTY at higher rotor speeds.

3.4 Appearance of Spun-like Filament Yarn and Fabric

Fig 8 clearly shows the surface appearance of the yarn and the fabric weaved by the spun-like filament yarn . The single spun-like filament obviously possesses a hairy structure successfully owing its wrapped yarn. However, the woven fabric possesses less hairiness on the yarn surface. It can be attributed to the effect of reed strike at the yarn surface. For the purpose to enhance the hairy structure of fabric , the boiled water setting process can be used.

4 Conclusions The hairiness is an important characteristic for the

filaments to simulate the hand feeling of ordinary

282 INDIAN 1. FIBRE TEXT. RES., SEPTEMBER 2004

staple yarn. A novel rotor twister can produce the spun­like filament yam successfully by using common polymer fibre with a high wrapping speed. This spun­like filament yam can be used to make a woven or knitted fabric wiper or mop for cleaning, to make clothing, or to serve other industrial purposes. The spun­like filament yam fabricated by the rotor twister method can be used industrially because of its greater strength and elongation than regular spun-like yam. With the twist multiplier of 1.4, rotor speed of 8000 rpm and grinding wheels of (60# + 120#), the spun-like filament yam shows better imitated hairiness compared to other processing conditions. With the twist multiplier of 1.8, rotor speed of 12000 rpm, count of 115 tex, and grinding wheels of (60# + 180#), the spun-like fil ament yam has better mechanical propelties with the strength of 27.10 cN/ tex and elongation of 15.89 %.

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