Indian Journal of Fibre & Textile Research Vol. 34, March 2009, pp. 47-51 A novel approach to process cotton/long staple fibre blends on short staple ring frame D Saravanan a & S Sathis Kumar Department of Textile Technology, Bannari Amman Institute of Technology, Sathyamangalam 638 401, India Revised received 21 May 2008; accepted 4 July 2008 An attempt has been made to blend cotton fibres with long staple fibre strands made of silk and polyester-wool using siro spinning system and to evaluate the samples produced for some physical properties. Blending of these fibres using siro spinning appears to be possible at low spindle speeds. Yarns produced in the modified drafting system show better moisture content, evenness and hairiness, and these properties are influenced by the cotton fibre content in the blended yarn. Keywords: Hairiness, Index of irregularity, Moisture content, Poly-wool, Silk, Siro-spun yarn, Tenacity 1 Introduction In siro spinning, two similar or different roving strands are fed into the drafting zone and maintained separately throughout the drafting process till the nip of the front roller, using suitable guides in the middle zone and also prior to delivery rollers. At the nip of the delivery roller, both the strands are condensed, twisted together and wound by the spindle. Convergence of strands at the delivery roller is governed by spinning speed, strand twists and fineness of the yarn; optimal convergence angle of the two strands in equilibrium is 90° with resonance at 127° (refs 1,2) Many attempts have been made earlier to process worsted roving materials on the cotton ring spinning system with suitable modifications in the drafting system, though the longer wool fibres are stretch-broken. 3,4 Also, extensive works have been carried out in the siro spinning using short staple spinning system, nevertheless the literatures related to siro spinning of cotton and long staple fibres are not available. Effects of strand spacing, apron spacing, yarn twist, spindle speed and break draft on yarn tenacity, elongation, evenness, hairiness have been studied earlier using cotton 5-7 , viscose 8,9 , acrylic 10 , polyester-cotton 11 , polyester-viscose 11 , jute-cotton 12 blends in short staple spinning systems. Attempts have also been made to produce polyester-wool blends 13 with the optimized strand spacing in the drafting zones in the short staple fibre ring frame. In the present work, an attempt has been made to produce cotton/polyester-wool and cotton/silk blended yarns through short staple spinning process by modifying drafting zone of the short staple spinning system. 2 Materials and Methods 2.1 Materials Cotton fibres (MCU-5) with 1.46 dtex (3.7 g/inch) fineness, 29.4 mm span length (2.5%) and 13.9 mm span length (50%) were used to produce cotton roving with 0.369 ktex linear density through short staple spinning preparatory machines (M/s Ramakrishna Spinning Mills, Coimbatore). Silk roving was produced from mulberry silk with a linear density of 0.492 ktex (1.3 dtex per fibre, 94mm average length and CV% 23) through long staple spinning preparatory system (M/s Himatsinghka Filati, Bangalore). Long staple polyester-wool (75:25) blended roving with a linear density of 0.295 ktex was produced using the variable cut length polyester fibres (2.2 dtex) with a mean fibre length of 72 mm (CV% 4.2%) blended with merino wool of 22.5 micron diameter and Hauter average length of 75 mm (CV% 35%). The wool was procured from M/s Raymond India Limited, Vapi. Both silk and polyester-wool (here after poly-wool) blends were processed on NSC FM7N rubbing frame with 5 rubs/m. 2.2 Methods 2.2.1 Spinning Double rove spinning of cotton/silk and cotton/poly-wool roving materials was carried out in _________ a To whom all the correspondence should be addressed. E-mail: dhapathe2001@rediffmail.com