Properties of man-made fibre yarns spun on DREF-3 spinning system

Transcription

1 Indian Journal of Fibre & Textile Research Vo. 16, December 1991, pp Properties of man-made fibre spun on DREF-3 spinning system A R Padmanabhan The South India Textile Research Association. Coimbatore India Received 16 April 1991: accepted 29 May 1991 To explore the potentialities of the DREF-3 friction spinning system for processing man-made fibres. 6s and 12s were produced from 100% polyester. 100% viscose. polyester/cotton and polyester/viscose blends. The properties of these were studied and compared with those of the equivalent rotor- and ringspun. The results indicate that the ring from 100% viscose and 100% polyester are stronger than the corresponding DREF and rotor by about 8% and 50% respectively. In polyester/viscose blended. as the polyester content increases from 52% to 70%. yarn breaking strength increases by about 65%. but unevenness and imperfections do not show any significant improvement. Keywords: Blended, DREF - 3 spinning, Yarn strength, yarn irregularity 1 Introduction DREF-3 friction spinning system is considered to be one of the versatile systems in short staple spinning for cotton, man-made fibres and their blends. A unique feature of the DREF-3 system is that it enables to predetermine the radial position of fibres in the yarn cross-section by changing the relative position of core and wrapper slivers. This facility is made use of in the production ofbicomponent. While a limited number of publications are available regarding the properties of all-cotton DREF, corresponding information relating to DREF from man-made fibres and their blends is not available. A recent study' at SA WTRI on DREF from man-made fibre revealed that the properties of DREF-3 are intermediate between those of rotor and ring and the overall quality of fine count DREF-3 is far superior to that of the coarser. Therefore, a detailed study was conducted to assess the processing performance and properties of 100% viscose, 100% polyester, polyester/cotton and polyester/viscose blended spun on the DREF-3 spinning machine and the properties of these were compared with those of equivalent ring and rotor. 2 Materials and Methods In the first phase, spinning trials relating to viscose fibres were completed. In the second phase, 100!Yo polyester fibres were spun to various counts and in the third phase, polyester/cotton and polyester/viscose blended were produced in different blend proportions. The process parameters employed in DREF-, rotor- and ring-spinning trials are given in Appendix I % Viscose Yarns Second passage drawframe slivers of 0.18 hank from 1.4 den x 44 mm viscose fibres oflndian origin were spun to 6s, 12s and 18s counts in DREF-3 spinning system without any additional core. Viscose slivers of 0.18 hank were processed on M 1/3 Lakshmi-Rieter rotor spinning machine to spin 6s, 12s and 18s rotor. For spinning eq uivalent ring, a laboratory model NMM ring frame with WST drafting system was used % Polyester Yarns 100% Polyester in 6s and 12s counts were spun from second passage drawframe sliver of 0.18 hank of indigenous polyester fibres in both DREF (without any additional core yarn)- and rotor-spinning systems. Due to the poor spinning stability, 18s count could not be produced in both DREF- and rotor-spinning systems. The equivalent ring were spun on a laboratory model ring frame. 2.3 Polyester/Cotton and Polyester/Viscose Blended Yarns Polyester/viscose blended were spun from 1.4 den x 44 mm polyester and viscose fibres. In the case of ring, drawframe blending was carried out to produce 48/52, 67/33 and 70/30 polyester/viscose. 241

2 INDIAN J. FIBRE TEXT. RES., DECEMBER 1991 For spinning DREF, the above polyester and viscose fibres were used as core and wrapper respectively to obtain P/V of different blend proportions. In a similar way, polyester/cotton blended were spun from the same polyester fibres with blend of Sankar-4 cotton slivers. 2.4 Tests The yarn samples were tested for single yarn tenacity and breaking elongation (%) on an Uster tensorapid tester (constant rate of elongation). Yarn unevenness and imperfections were determined on the Uster evenness tester (model II-B) using standard settings. Hairiness was measured on a Shirley yarn hairiness meter at the standard distance of 3 mm. All the tests were carried out at 65 ± 2% RH and 27 ± 2 C using standard test procedures. 3 Results and Discussion /. Viscose DREF Yams The properties of 100% viscose spun on DREF-3, ring- and rotor-spinning systems are given in Table 1. It is observed that the breaking strength varies between 1660 and 518 g, 1585 and 648 g, and 742 and 361 g for DREF, ring and rotor respectively. On an average, the ring are stronger than the corresponding DREF and rotor by about 0-25% and 45-75% respectively in 12s and 18s. But in 6s, D REF are stronger than both ring and rotor by about 5% and 130% respectively. However, the yarn strength decreases gradually as the count becomes finer in all types of yarn (Fig. I). The strength irregularity (CV %) is higher for DREF compared to ring and rotor for any given count. As expected, rotor, in general, exhibit the minimum strength CV %. The per cent elongation at break for ring is higher than those for rotor and DREF by about 12% and 21% respectively. However, the per cent elongation decreases as the count increases from 6s to 18s invariably in all the three. Yarn unevenness (U %) is low for ring and it ranges between 9.0 and to.8in DREF, 7.8and 9.9 in ring, 10.2and 12.5in rotor. The high U % noticed for rotor could be mainly due to the employment of a low draft of about 33 as against 60 recommended by the OE machinery manufacturer. As expected, the unevenness values of all types of yarn increase as the count becomes finer. Yarn imperfections are very low in ring but quite comparable in DEF and rot?r except in the case of 6s count. Generally, the imperfections do not show any particular trend withregard to yarn linear density. 2000r x - Ring.- OrE-I 1600 X, o- Rator, s:, c 0> 1200 ".. in x, 0> x <, ,l( ClI CD " " " Count,Nt' Fig. I-EffeCt of count on breaking strength of 100% viose Table I-Properties of viscose spun on DREF-3, ring- and rotor-spinning systems DREF Ring Rotor 6s I2s 18s 65 12s 18s 6s 12s 18s U% Thin places/krn _Thick places/krn N'eps/km ISO Breaking strength, g Strength CV % Mean elongation at break, % Hairs/m

3 PADMANABHAN: DREF-3 SPINNING By and large, DREF are more hairy than ring and rotor. The average number of hairs/m is around 8 in rotor, 22 in ring and 44 m DREF. The high hairiness in DREF could be attributed to the spinning process itself. Yarn hairiness decreases with increase in count in all the three spinning systems Polyester Yams Table 2 shows the properties of DREF, ring and rotor produced from 100% polyester fibres. It is observed that ring exhibit higher breaking strength than the corresponding DREF and rotor by about 32% and 50% respectively. The strength decreases as the count becomes finer in all the cases (Fig. 2). The higher breaking strength observed in ring may be explained as follows. In ring, the majority of the fibres are twisted along the longitudinal axis of the yarn and all these fibres contribute to the overall strength of the yarn, whereas in rotor and DREF, a considerable number of fibres are loosely wrapped around the yarn and these wrapped fibres do not contribute as much to yarn strength as the helically twisted fibres in the ring yarn. As far as the strength irregularity is concerned, no spinning system offers a consistent trend for both 6s and 12s counts. In general, the unevenness of ring yams is better than those of DREF and rotor and it increases steadily as the count becomes finer in both ring and DREF but in rotor, an opposite trend is observed (Fig. 3). The unevenness of 12.3 U% observed for 6s rotor yarn appears to be quite high and this is mainly due to the employment of a very low draft of 33 as against 60 recommended by the manufacturer. Yarn imperfections are comparatively low for DREF in 6s, but in 12s, both rotor and ring have less imperfections than DREF. In 6s rotor, the imperfections are very high. This may 3000 Ol 2600 Ol 2200 OIl o CD 1400 Ring x J--- o Count,Ne Fig. 2-Effect of count on breaking strength of 100% polyester 18r , s 10s D16s Dref yarn Ring yarn Rotor yarn Fig. 3--Effect of yarn count on U ster U % of 100% polyester Table 2-Properties of polyester spun on DREF-3, ring- and rotor-spinning systems DREF Ring Rotor 6s 12s 6s 12s 6s 12s U% Thin places(km Thick places(km Neps(km Breaking strength, g Strength CV % Mean elongation at break, % Hairs(m

4 1()ltI', J. fibre TEXT. RES.. DECEMBER 1991 be due to the poor opening action of the combing roller owing to insufficient drafting in that particular region. Hairiness in DREF is significantly higher than in rotor and ring and it decreases as the count becomes finer. 3.3 Polyester/Viscose Blended Yarns The properties or polyester/viscose (P/V) and polyester/cotton (P/C) blended spun from DREF-3 and ring spinning systems are given in Table 3. The table clearly indicates that the per cent polyester content in P/V DREF has a striking influence on many yarn properties. As the polyester content increases from 52% to 70%, yarn breaking strength increases by about 65% (Fig. 4), strength irregularity decreases by about 50%, and breaking elongation increases by about 15% (Fig. 5). Yarn unevenness and imperfections do not show any significant improvement with increase in polyester content up to 67%, but as the polyester content reaches 70%, yarn unevenness decreases by about 1.2 U%. All DREF are hairy and the hairiness is not at all the influenced by the amount of polyester content. Since the corresponding P/V ring and DREF yams were not available, a comparison was made between 52/48 PjV DREF yam and 48/52 P/V ring yarn (Table 3). It is observed from Table 3 that the ring yam shows nearly 45% higher breaking strength and 72% lower strength CV % than the DREF yam. But DREF yam exhibits lower unevenness, lower imperfections and higher hairiness than ring yarn. A part of the ' c 01 c 1500.x 1000 o <lj ID, ", -," -, " "" -, -, Vi c.2 ' c o W, " < 500 lol--l-j---j-j----o Polyester,0'0 Fig. 4--Effect of polyester content on strength of polyester-viscose DREF yarn o a Polyester, "I. Fig. 5-Effect of polyester content on elongation of polyester-viscose DREF yarn Table 3-Properties of blended spun on DREF-3 and ring spinning systems DREF Ring PlY PIC P/Y PIC (70/30) (48/52) (67/33) 52/48 67/33 70/30 U% 8.8 lu IU; Thin places/krn Thick places/km Neps/krn Breaking strength. g Strength CY % Mean elongation at break. % I Elongation CY % Hairs/rn

5 PADMANABHAN: DREF-:I SPINNING differences observed in various yarn properties could be attributed to the locational difference of the individual fibres in the blended. 3.4 Polyester/Cotton Blended Yarns Table 3 shows that the 70/30 polyester/cotton DREF yarn exhibits 32% higher breaking strength than the corresponding ring yarn. This difference could be attributed to the higher polyester content in DREF yarn. Also, the DREF yarn is more uneven by about 4.6 U% than its ring counterpart. DREF are poorer in yarn imperfections, strength irregularity and hairiness than ring. 4 Conclusions 4.1 DREF-3 spinning system can be employed to produce 100% polyester, 100% viscose, polyester/ cotton and polyester/viscose up to a limiting count of 18s. In blended, the radial position of fibres in the yarn cross-section can be predetermi ned. 4.2 On an average, the ring from 100% viscose and 100 /" polyester fibres are stronger than the corresponding DREF and rotor by about 8% and 50% respectively. The yarn strength steadily decreases as the count becomes finer in DREF-3 spinning system also. 4_3 Unevenness and imperfections are generally low for both 100% viscose and 100% polyester produced on ring spinning system. The improvement, however, depends upon the type of fibre and the count to which it is spun. 4.4 By and large the DREF spun from 100% polyester and 100% viscose fibres are more hairy than ring and rotor and the hairiness decreases as the count becomes finer. 4.5 In polyester/viscose blended. as the polyester content increases from 52 to 70%, yarn breaking strength increases by about 65% and breaking elongation increases by about 15%, but unevenness and imperfections do not show any significant improvement. 4.6 Polyester/cotton DREF yarn is superior to ring yam in yarn strength by about 25% but it is inferior in unevenness, imperfections, strength irregularity and hairiness. Acknowledgement The author is thankful to the Ministry of Textiles, Government of India, for sponsoring this project. References I Thierron W & Hunter L. SA WTRI Technical Report No Appendix I-Details of process parameters employed in DREF-, rotor- and ring-spinning systems DREF-3 Spinning Drum speed Combing roller speed Production rate Input sliver hank No. of slivers in drafting system I No. of slivers in drafting system II Rotor Spinning, Rotor speed Combing roller speed Rotor diam. Input sliver hank Machine TPI Ring Spinning Spindle speed TPI Input roving hank range : 4000 rpm : rpm : 200 mjmin : 0.18 : 5 : I : 40,000 rpm : 6000 rpm : 54 mm : 0.18 : : 10,000 rpm : :