Indian Journal o f Fibre & Tex tile Research Vo l. 29, March 2004, pp. 25-29

Application of rotor wrapping twister for luaking ply yarn from nonwoven selvedges

Ching Wen Lou

Chungtai In stilUte of Health Scie nces and Techno logy, Taichung 406, Tai wan

and

Jia Horng Lin"

Laboratory o f Fiber Manufacturing and Appli cati o n, G raduate InstilUte o f Textil e Eng ineering, Feng Chia Uni versity, Taichung 407, Tai wan

ReceiFed II February 2002: revised receil'ed 21 April 2003; accepted 14 May 2003

A novel ro tor wrapping twister has becn used for preparing pl y yarn consisting o f po lypropyle ne nonwoven se lvedges, copper wires and po lyes ter filaments. It is observed that the ply yarn produced with thi s roto r twi ster possesses superior e lec trical and mechani cal properties due to the nalUral characte ri stics of the fil aments. The ply yarn has been produced on the rotor wrapping twister under different conditions o f twi ster count and rotor speed and then wo ven on a rapi er loom. By varying manufac turing parameters, the he li x angle and lightness of the twist-wrapped yarn can also be changed to enhance its mechanical properti es and e lec tromagnetic shi elding e ffecti veness . The optimal conditions for producing the ply yarn wrapped with metallic filam ents are 8000 rpm ro tor speed and 2.5 turns/c m warping count , and that for wrapped with po lyester filame nts are 6000 rpm and 1.0 turn/cm.

Keywords: Me tallic fibre, Nonwoven selvedge, Pl y yarn, Po lyester, Po lypropylene, Rotor wrapping twi ster IPC Code: Int. CI.7 D02G 3/00, DOIH 7/00

1 Introduction A survey conducted by the Taiwan Environmental

Protection Administration in ] 998 revealed that approximately 18 million metric tons (-500 tons/km2

)

of industrial waste is produced in Taiwan each year which is 650 tons/km2 in Japan I . According to the Waste Disposal Act 2, the generators of industrial waste need to manage the waste themselves or may have contract for industrial treatments with qualified companies to dispose of their industrial waste. However, 96% of the enterprises in Taiwan are small or medium sized. Many of them still need skills , manpower, economic scales, technology, equipment and ploneenng vI sion for industrial waste management. Therefore, in order to reduce environmental loading and to effectively use resources, promotion of recycling and reuse of industrial waste are very important3

.

In a previous research , Aspiras and Manal04 tried to mix textile waste cuttings and cement as binder to produce a unique composite material that looked like

"To whom all the corresp(,n J cnce shou ld be addressed . Phone: 245 1866 1; Fax: 886-4-2451 0~71 ;

E-mail: jhlin @fcu.edu.tw

concrete but could be cut or nailed like wood . The composite exhibited certain physical and mechanical properties, indicating its potential of low cost and light weight.

Recently, Lin et al. s.6 innovated rotor twister to make the ply yarn . The rotor wrapping twister can wrap the selvedges with other filaments using different rotor speeds and wrapping counts to make the ply yarn7

.8

. In the present work, this novel rotor wrapping twi ster has been used for preparing ply yarns from polypropylene nonwoven selvedges, copper wires and polyester filaments. The core materials and wrapping materials were changed to investigate the maximum breaking strength and elongation of the fabrics .

A promising way to add the economic value of the plied yarn is to combine the nonwoven selvedges and rei nforcement materials which are manufactured using the twi st-wrapping techniques. After combi ning with s el vec1ge ~ , polyester and copper can offer several advantages for their high tenacity , high modulus and high electrical conductivity. As for the nonwoven selvedge, it is hard to weave without any fini shing because of its fl at appearance and unevenness. However, the aforementioned innovated rotor twister

26 INDI AN J. FIBRE TEXT. RES. , MARCH 2004

Tab le I- Properties 01 materials used

Material

Polypropylene nonwoven selvedge

Po lyes ter filament

Copper wi re

Spec i ficati on

Weigh t. 30 g/m~ ; Width , 3 cm

1200 den/9(i fi lament s

Di ameter, 0.08 mm

can combine the selvedges and other filaments directly. The highest speed of the rotor twister can exceed 30,000 rpm , which can assist in reducing the waste polluti on. In addition, the influence of process ing parameters on mechanical properti es and electromagnetic shi elding e ffectiveness o f the fabrics has also been studi ed.

2 Matel"ials and Methods Polypropyl ene nonwoven selvedges, polyester

filaments and copper wires with basic properties as shown in Table I were selected for study. All the three components were commi ngled simultaneously. Polypropylene nonwoven selvedges were used as the core yarn ~lIld polyester filaments and copper wires as the core or wrap yarn respecti ve ly. The combinations of th e core and wrappi ng material s are shown in Table 2. The roto r wrapping twi ster was used to wrap the core material s with the wrapping material s. The roto r speed and take-up speed o f the machine were measured and detec ted by the infrared device (M icrotech 8400). In addition, the tensioning device (SHARP Limit 2000 gf) was set on the machine to control and adjust the tension of the system.

The twi st-wrapping process of the rotor wrapping twister is described as fo ll ows. A tangent belt of the moto r dri ves the rotor spinning device of the rotor wrapping twi ster. The front side of selvedges and wrap yarn are dragged by a take-up ro ller. The tension-controlled ro ll er ho lds the other end of the selvedges. When the wrap yarn is untied , the waste passes through the middle of the rotor spinning device at the same time. T he wrap yarn gets twisted and wraps the waste along with the rotation of the rotor spi nning devi ce and then finishes the nonwoven selvedges twi st-wrapping process. The twi st-wrapping mechanism of the rotor wrapping twister is shown in Fig. I .

To spin pl y yarn successfully and efficientl y, the rotor speed had to correspond wi th the materials5

.8

.

The experiment was carried out using different rotor speeds (6000, 7000 and 8000 rpm) and wrapping counts ( I, 1.5, 2 and 2.5 turns/cm). The maximum

Count Tenac ity Strength Elonga ti on lex cN/tex N %

900.00 5.76 54.90 28.36

125.00 46.96 58.70 32.60

46.40 3.01 1.40 13.70

Table 2-Combinati ons of the core and wrappi ng materi als

Combinat ion Wrapping filament

Type A Polyester

Type 13 Copper

Core filam en t

Copper and polypropy lene

Po lyes ter and polypropylene -----------------------

Fig. I- Rotor wrapping twister [I - Wrap yarn. 2- Rotor spinning device, 3- Tangent be lt, 4-Take- up ro ller. 5- Tension contro lled roller, and 6- Selvedge)

production speed was 80 m/mi n under these conditions. The rotor speeds and wrapping counts on the max imum breaking strength and elongati on of ply yarn are shown in Table 3. The ply yarns were then woven into fabrics on a Rapier loom (Italy So met AC2/S) using 111 plain weave, 35.4 ends/lO em warp density and 19.6 ends/lO cm weft densi ty. The warp was polypropylene tape and the weft was ply yarn as shown in Fig. 2. Thermally bonded polypropylene nonwoven selvedges (Fig. 3) were used as the core material to produce ply yarn (Fig. 4) .

Tensile properties of the experimental yarns and fabrics were determined by using a computer servo control materi al testing system (Hung Ta Instrument Co. Ltd HT -910 1). The fab rics were tested accordi ng to ASTM D 5035 (strip method) standards. The settings were used on the testing system for the ply yarn according to ASTM D 2256. A coaxi al transmission line method was used to test the EMSE (electromagnetic shielding effecti veness) of conductive woven fabrics. The measurement was

LOU & LIN: PLY YARN FROM NONWOVEN SELVEDGES 27

Table 3---Maxilllull1 breaking strength and elongati on of Type A and Type B ply yarns

Yarn Wrapping count Max. breaking strength, N Max. breaking elongation ,% turn s/cll1 6000" 7000" 8000" 6000" 7000" 8000"

1.0 75.90 79.08 82. 15 34.83 37.94 39.08 Type A 1.5 70.4 1 72.58 78.68 3 1.86 35.84 40.73

2.0 66.03 68.54 75.72 29.87 32. 10 39.43 2.5 60.55 67.4 1 73.8 1 27.86 29.06 37.43

1.0 7 1.36 74.20 76.m 13.75 17.25 19.44 Type B 1.5 75.38 77.37 8 1.1 8 15.66 20. 12 2 1.97

2.0 78.3 1 79.52 83.66 19.78 22.23 24. 14 2.5 80.0 1 8 1.88 85.0 1 22.58 23.95 26.46

"Rotor speed in rpm

Copper filament (Wrap yarn )

(a) (b) Fig. 2-(a) Fabric structure (fa bric coun t, 9 cnds/in. x 5 picks/in. ), and (b) Pl y yarn structure

(BY - -

Fig. 3-WaSlcd nonwoven selvedge (A) and its ply yarn (8 )

carried out with the spectrum analyzer and the EM-2 107 A shielding effectiveness test fixture (electro metrics) to fix the testing sample, The fixture is an enlarged sect ion of coax ial transmission line and compl ies fully with [he req uirements of ASTM D 4935-99.

3 Results and Discussion Table 3 shows the maximum breaki ng strength of

the two types of ply yarn . The maximum breaking strength of the ply yarn wrapped with polyester f ilaments (Type A) increases with the increase in rotor speed . This is because that the centri fuga l force from wrapping rotor makes the structure tight. However, the polyeste r filaments are the main source suppl ying the trength to the whole ply yarn. A greater twi st-wrapping angle of the ply yarn wrapped with polyester filaments would results in a decrease in fo rce in ax ial di rectio n. Therefore, the maximum breaking strength o f the ply yarn dec reases with the increase in twi st-w rapping counts.

When the polyester wrapping filaments are substituted with copper wires to produce ply yarn , a diff ;1 CI,t mechan ical tendency is observed . The m:l.X .1." ~ l' ,lking strength of ply yarn wrapped with copper Wl re~ (Type 8) increases owing to the tightness of the: yarn because o f the increased rotor speed and twist-wrapping counts.

T he maximum breaking strength of th~ Type A fabrics decreases with the increase in wrapping cou nts

28 DIAN J. FIBRE TEXT. RES. , MARCH 2004

Fi g . 4-Ply yarn s Irotor speed. 8000 rpm ancl wrnpping count. 1.0-2 .5 (in 0.5 s tep) in unit length]

Table 4-Maximulll breaking strength and elongation of Type A and Type B fabri cs [Width o f fabri c. 2 .54 cm]

Fabric Wrapping count Max. break ing strength , N Max. breaking e longati on.'ro turn s/em 6000" 7000"

1.0 296. 71 320.50 Type A 1.5 272.66 289.50

2.0 243.62 265.62 2.5 21 8.57 25 1.1 5

1.0 230.9 1 252.05 Type B 1.5 253.37 272.32

2 .0 268.43 286.71 2.5 289.80 305.44

" Rotor speed in rpm

at the sa me rotor speed (Table 4). Because the wrapping angle between the core and wrapping materials increases with the wrappi ng counts, the ax ial component of the wrapping fi laments dimini shes and the max imum breaking strength of the ply yarn decreases. Therefore. the max imum breaking strength of the fabrics made of the ply ya rn also decreases . However, the maxi mum break ing strength of the fab ric increases while increasing the rotor speed, though the wrapping counts are the same. With the increase in rotor speed, the wrapping filaments are subjected to higher centri fugal force. Consequently , the ply yarn is wrapped more ti ghtly and its structure becomes even.

Si mil arl y, the maximum breaking strength of Type B fab rics increases with the rotor speed (Table 4). When the ro to r speed is increased, the ply yarn is subjected to higher centrifugal force , resulting in an increase in its modu lus. At the same time, the maximum breaking elongati on of the fabrics also increases.

The maximum breaking elo ngat ion of ply yarn wrapped with polyester f il aments and copper wires is shown in Table 3 . T he core part of the ply yarn was composed of polypropylene nonwoven selvedges and copper wire. The maxi mum breaking elongation of

8000" 6000" ·'000" 8000"

346.79 29.66 32.98 36 .99 32 1. 81 27. 19 30. 15 33.2 1 299. 1 I 24. 19 27.4 1 30.76 280 .77 2 1.37 23.82 2 7.20

268.20 9. 76 12.27 14.22 294.57 10.90 13.38 15.01 308.03 12.88 14.32 15.97 329.35 13.37 15.29 17.03

ply yarn dec reases while the twi st-wrapping count increases . It could be attributed to the entrali zed yarn wrapped by polyester filaments with a promoting twist-wrapping level. Thus, the extended ability of the core part of pl y yarn is li mited. Tabl e 3 also shows that the max imum breaki ng elongati on of ply yarn with a core composed of polypropylene nonwoven selvedges and polyester fil aments increases wi th the increase in twist-wrapping counts. It could be attributed to the smooth surface of copper wires with a low interfac ial friction between po lypropylene nonwoven selvedges and po lyester filaments . Low frictional force would lead to increase in the ex tended ab ility of the core part of ply yarn.

A higher rotor speed g ives a greater max imum breaking elongation of the core part in ply yarn (Table 3) . It shows the excellent stability performance o f ply yarn wrapped with copper wires . The ply yarn also exhibits higher maximum breaking elongation than the fabrics since the polyester filaments with superior mechanical properties are wrapped in the ce nter of the ply yarn.

The maximum breaking elongation of the fab ri cs woven with ply yarn wrapped by po lyes ter filaments or copper w ires is shown in Table 4. The maximum breaking elongation of the fabr ics is approx imately

LOU & LI : PLY YARN FROM NON WOVEN SELVEDGES 29

the same as that of the original ply yarn . The maximum breaking elongat ion of the Type A fabrics decreases with the increase in twi st-wrapping counts . When the rotor speed increases, the ply yarn is subjected to higher centrifuga l force resulting from the wrapping moti on. Therefore, the compact structure of pl y ya rn was created and the axial stress of the core material s (polypropylene nonwoven selvedges and copper wires) was increased , resulting in the increase in maximum breaking elongation.

Table 4 shows that for the Type I3 fabric s (copper filament as wrapping yarn), the innuence of material s, by varying the twi st-wrapping counts of the hybrid fabrics, on the maximum breaking elongation is so obvious that the maximum breaking elongation of ply yarn increases with the increase in twi st-wrapping counts. It could be attributed to the low frictional coefficient of copper wires that causes tight structure of the core part of ply yarn. Therefore, the ply yarn could endure more stress. Owing to the excellent mechanical performance of the ply yarn, the variation in maximum breaking elongation of hybrid fabrics is small.

Table 5 shows the strength utilization factors of Type A and Type I3 fabrics. When the rotor speed increases, the utilization factors also increase relatively . The ply yarn would possess an even structure when it is wrapped at a high rotor speed and, therefore, the whole fabric made of the ply yarn shows an even and nat structure due to the excellent strength utilization factors. Moreover, the variations in strength utilization factors of Type A and Type B fabrics with different wrapping levels show similar trends and reasons as to those of the ply yarn.

The electromagnetic shielding effectiveness (EMSE) of the ply yarn fabric was measured in the range of 30-3000 MHz. As shown in Fig. 5, the wrapping material of the ply yarn fabric is a copper wire with the wrapping count of 2.0 turns/cm and rotor speed of 8000 rpm. The copper wire (4.45 wt%) is used for the fabric weight of 305.65 g/m2 and a shielding level of 10-20 dB can be achieved.

4 Conclusion Rotor wrapping twister has been used successfully

without the restrictions of yarn count and number of folds. Multifunctional ply yarn has been prepared by combining selected materials (copper wires, polyester filaments and nonwoven selvedges) at over 6000 rpm speed. The reinforced filaments show different physical properties, irrespecti ve of whether they are

Table 5- Maximum break ing strength utili zation factors of Type A and Type I3 fabri cs

Fabric Rotor Maximulll break ing strcngt h utili zati on spced factor.% rpm 1.0" 1.5 " 2.0 " 2.5 "

6000 78. 18 77.4.f 73.79 72.20 Type A 7000 8 1.05 79.78 77.5 I 74.5:2

8000 84.43 8 1.81 79.00 76.08

6000 64.72 67.22 68.56 72.4.f Typc I3 7000 67 .94 70.40 72. 11 7.f.60

8000 70.55 72.57 73.64 77.49

"Wrapping coun ts, llIrns/clll

~ 100

l \

~ 80

B ~60 ::s ~ 40 I ;:!J ~20 .= --~~----.,.....-... ~ 0 ' , , ,~~::=:==J .~ 0 600 1200 1800 2400 3000 Vl frequcncy (M ll z)

Fig. 5- Electrolllagnctic shielding effect ivencss of the fabric with 2.0 turns/c lll of the wrapping coppcr wire

inner or outer of the ply yarn. It also shows that the physical properties of the functional ply yarn and fabrics are innuenced by the materials and the producing process . The electromagnetic shielding effectiveness of the fabrics is found to be 10-20 dB for copper filament (4.45% by weight). The optimum conditions of the ply yarn wrapped with the metallic filaments are 8000 rpm rotor speed and 2.5 turns/cm wrapping count, and of that wrapped with polyester filaments are 6000 rpm and 1.0 turn/cm.

References I £//I 'irolllllell/{li Reporl (Japan Environlllcnt Agency), 1999. 2 Wasle Disposal Au (Environmcntal Protcction Admini strat ion.

Taiwan), January 2000. 3 Wei M S & Huang K H, W'({sle Mallagelllelll, 2 1 (200 I) 93. 4 Aspiras F F & Manalo J R I, Utilization of tex tile waste

cUllings as building matcrial , J Mater Process Tec/Ill o/. 48 ( 1995) 379.

5 Lin J H. The SIIIt/v{or Ihe rolOr IlI'isl lIl({chille, M S thesi s The Graduate In stitute of Textile Engineering, Feng Chia Uni versity. Taiwan, ROC, 1992.

6 Lin J I I. Tsai I S & Ii sing W II , Introduction to an innovative rotor twi ster, J Texl IIISI , 89 ( 1998) 266.

7 Lin J H, Tsai I S. Hsing W H & Yang Z Z. The innuence or the twi st dircction on the physical properties of a pli ed yarn in a rotor twi ster, J Texl 111.1'/ , 89 ( 1998) 480.

8 Lin J H, Tsai I S. Lou C W & Hsing W H, The possibility of the producti on of double or plied yarn using the selvedge waste fro m the Shulliciess 100111. J HlVa Gang Te. l"/. 4 (1997) I.