Indian Journal of Fibre & Textile Research Vol 29, December 2004, pp. 436-439 Characteristics of dref-3 yams with jute in core S Mukherjeea & P K Majumdarb College of Textile Technology, Serampore 712 201, India Received 30 June 2003; revised received and accepted 3 December 2003 J The tensile properties of jute-acrylic and jute-cotton dref-3 yams with jute in core have been studied. The tenacity of dref-3 yams was found to be lower but the strength translation efficiencyof jute fibres was higher when used in the core of jute-acrylic dref-3 yam as compared to that when used in the flyer yarn structure. Stick-slip pattern of failure was observed in case of dref-3 yams, whereas catastrophic failure was observed in case of jute flyer yarn. Breaking elongation and specific work of rupture ofthe dref-3 yarns were higher than those of the jute flyer yam. Keywords : Dref-3 yarn, Jute-acrylic yarn, Jute-cotton yarn, Modulus ratio, Packing coefficient, Stick-slip pattern, Tensile properties 7 IPC Code: Int. C1 • DOlH 13/26, D020 3/00, D06H 3/00, OO IN 33/36 1 Introduction Stronger and longer fibres in the core produce Dref-3 friction spinning technology has established stronger yarns; higher core/sheath ratio gives better its commercial success in the coarse and medium strength, whereas lower core/sheath ratio gives better count range. The yam consists of a core made of cover. Jute blended dref-3 yam is being used as weft bundle of staple parallel fibres and a sheath where the on various looms to produce denim and Oxford staple fibres are regularly twisted in a helical fashion fabrics. Dusting of jute blended dref-3 yam on around the core. The strength of such a structure is shuttleless looms is appreciably lower as compared to largely dependent on the magnitude of radial pressure similar yam spun through the other spinning systems exerted by the sheath fibres on the core fibres. due to the presence of lesser jute fibres on the surface Although considerable research work has been even when the jute content is around 53%. Oxford carried out to study the viability of spinning different fabric with specialty finish is found to be quite fibres into yarn by this systeml-7 of spinning, very comfortable and almost free from any pricking little published work 8-10 is available on the use of jute sensation. fibres and no published work is available on the use As reported in the work carried out at Arvind Mills, of jute fibres in the core. Due to some inherent nature the payback period I I is 4.5 years for a cotton/polyester of jute fibre, blending of jute with finer and flexible mill which has to procure jute slivers from jute mills. fibres helps to improve the processing and The payback period is 6.6 years for a new dref-3 characteristics8 of dref-2 yarns. Jute fibre has been spinning plant which has to procure all the slivers used as sheath fibre in blends with other fibres in from cotton/polyester/jute mills. dref-3 system so as to cover it with high value fibre9• In the present work, the yarns have been spun by O There is a good effectl of stronger and longer jute dref-3 spinning system using jute fibres in the core fibres in higher percentage, either in the core or in the and acrylic as well as cotton as sheath fibres and the sheath, on the tensile properties of dref-3 yarn. tensile characteristics of these yarns have been Dref-3 yarn with jute in the intermediate layer is compared with those of conventional jute flyeryarns. quite strong and has significantly lower shedding tendency during subsequent high speed weavingll. 2 Materials and Methods 2.1 Materials apresent address : MPMMC Division, Indian Jute Industries' Jute fibres of Tossa-Daisee grade(TD-3), acrylic Research Association, 17 Taratola Road, Kolkata 700 088, India � staple fibres of 3 denier and 51 mm length and cotton o whom all the correspondence should IX: addressed. Phone : 2662 1058 ; Fax : + 91- 33 -2662 1058; fibres of Digvijay grade were used. Some of the E-mail : [email protected] physical properties of these fibres are given in Table!. MUKHERJEE & MAJUMDAR: DREF-3 YARNS WITH JUTE IN CORE 437 2.2 Methods and f2 , Specific volumes of jute, acrylic and cotton 2.2.1 Preparation of Yarn Samples fibres were taken as 0.7, 0.85 and 0.65 cc/g A twenty-spindle Mackie apron-draft spinning respectively. frame was used to spin the conventional jute yams of nominal linear density (175 tex) with four different 3 Results and Discussion twist multipliers (24.35, 25.56, 26.83 and 28.3) at a 3.1 Tensile Characteristics of Jute Flyer Yarns flyer speed of 3200 rpm. The twist-tenacity relationship is shown in Dref-3 machine was used to spin jute-acrylic and Fig.1 .The optimum tenacity value is observed at a jute-cotton yams of same nominal linear density at a twist multiplier of 25.56. The increase in strength at delivery speed of 75 m/min. The speeds of spinning low twist level is due to the increase in cohesive force and carding drums were maintained at 3750 and and fall in strength after optimum twist multiplier is 12000 rpm respectively. While jute sliver of 3.1 ktex due to the obliquity effect. was fed to the drafting unit 1, five slivers each of 3.2 ktex were fed to the drafting unit II in preparing both 3.2 Tensile Characteristics of Jute Blended Dref-3 Yarns jute-acrylic and jute-cotton yarns. Core-sheath ratio of 3.2.1 Tenacity 70:30 was maintained to achieve stable spinning The characteristics of jute, acrylic and cotton fibres condition. are shown in Table 1. Much lower value for elongation is observed in case of cotton fibres when 2.2.2 Evaluation of Tensile Properties compared with the normal values. This may be due to Tensile characteristics of all the fibres were tested the short and coarser variety as lower elongation on Zwick tensile tester (Model 1445) with a gauge \2 values are generally observed in shorter and coarser length of 10 mm. Average values of tenacity, varieties. breaking elongation and initial modulus were taken The tensile characteristics of jute-acrylic and jute­ for each type of fibres. Tests were carried out with cotton dref-3 yams are given in Table 2 along with cross - head speeds of 1, 5 and 10 mm/min for jute, the tensile characteristics of jute flyer yam at the cotton and acrylic fibres respectively. optimum twist multiplier of 25.56. Tenacity values of Tensile characteristics of the yam samples were both jute-acrylic and jute-cotton dref-3 yarns are tested on Instron tensile strength tester (Model 1195) found to be lower as compared to that of jute flyer­ with the gauge length of 500 mm and cross-head spun yarn. Jute flyer yam shows the highest and jute­ speed of 50 mm/min in all the cases. The average cotton dref-3 yam shows the lowest tenacity values values of fifty tests were taken for each yarn sample to evaluate tenacity, elongation, specific work of 11.4 rupture and initial modulus. 11.2 2.2.3 Evaluation of Packing CoefflCient The packing coefficient of each type of yam was computed from the ratio of bulk densities of yarn and 11 � fibre. The diameter of yam samples was measured on Q) ' a projectina microscope with the magnification of � 10.8 <oj X 20 . A pre-tension level of 0.025 cN/tex was used '" � for each yam sample. An average of thirty readings J.. 10.6 ... was taken for each yarn sample. Specific volume of m fibre in case of dref-3 yams was calculated by � 10.4 (Vr) .y <I.l taking the weighted average of specific volumes of 0- the two component fibres using the following m 10.2 relationship : 10 Specific volume of fibre ( Vr ) = ------ 9.8 4-.....JL-_.....L__ --L�-�--� XVt2+ YVfJ 24 29 Twist multiplier, turns/em x {tex where Vr \ and Vf are the specific volumes of fibres f\ Fig. 1 Effect of twist multiplier on tenacity of twisted jute yam 2 - and f2; and X and Y, the fractional presence of fibres f\ 438 INDIANJ. FIBRE TEXT. RES., DECEMBER 2004 while jute-acrylic dref-3 yarn occupies the fibres in the core, the initial modulus is found to be intermediate position. However, the tenacity of jute­ higher for both jute-acrylic and jute-cotton dref-3 acrylic dref-3 yarn is found to have higher value than yams. Table 2 also shows the ratio of yarn modulus that of jute flyer yarn when the tenacity is calculated and fibre Uute) modulus. The ratio is lower in case of on the basis of linear density of jute fibres at the core. dref-3 yarns than that in case of jute flyer yarn when This indicates higher strength translation efficiency of the count of the whole yam is considered. But when jute fibres at the core. Tenacity of jute-cotton dref-3 linear density of jute fibres in the core is considered, yarn is found to be still lower than that of jute flyer both jute-acrylic and jute-cotton dref-3 yarns show yam even when calculated on the same basis. It is higher values of modulus ratio than that of jute flyer evident from these results that the transverse pressure yam.