Effect of combing on spinning performance of quality cottons

Transcription

1 C. T. R.. L. f'ubllcatio:is ~"jew.:.>c.o;.:to 10 Effect of combing on spinning performance of quality cottons By B. Srinathan, S. Ramanathan, V. Sundaram and M.S. Parthasarathy (Cotton Technological Research Laboratory).

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3 Research &_ Development Effect of combing on spinning performance of quality cottons By B. Srinathan, S. Ramanathan, V. Sundaram and M.S. Parthasarathy (Cotton Technological Research Laboratory). The results of studies carried out on combing of two superior varieties of indigenous cottons, viz., Sujata and Hybrid 4, to different levels of waste extraction are incorporated in this paper. The combed yarns have been compared with combed yarns from imported Giza 45 and Sudan XG2 VS at identical levels of comber waste extraction. The study reveals that though the indigenous cotton yarns were slightly illferior to the imported cotton yarn in lea strength and unevenness, they were better in temls ofnep COUllt, a factor important especially in finer counts. Optimum levels for waste extraction for these cottons in terms of yam quality are also discussed. Il,)TRODUCTlON UNTIL recently the maximum spinnable count of the Indian cottons was around 40s. However, due to the intensive breeding programmes undertaken by the agricultural scientists under the All India Coordinated Cotton Improvement Project, quite a number of new strains in the long staple range, some of which can be spun to as high as 120s count, have been released by the State Agricultural Dt"partments. Under the present spinning procedures of the Cotton Technological Research Laboratory for assessment of spinning quality, the cottons are spun only to carded counts, contrary to the practice in mills who spin the superior quality cottons to the combed counts. Hence, it is imperative that the superior quality cottons that are now produced in the country be combed, so that their performance can be compared with that of imported cottons and the possibilities of import substitution by use of Indian cottons be explored. The importance of combing as a method of upgrading indigenous cottons has been recognised at CTRL as early as 1935 by 'J \'l<.\he Indian Textile Journal, May 1976 ~~~ Richardson and Ahmad 1. Possibilities were brought out by them of spinning 50s and 60s from cottons normally considered suitable for 30s warp. Differences in yarn quality by light combing of 8% and heavy combing of 20-25% were discussed by Ahmad in a later publication 2. Gupte and Iyengar 3 compared the performance of combed yams of good quality Indian cottons with those of carded Kampala cotton. The qualities of combed yarns of Laxmi and RajapalayamUganda were compared with carded yams of East AfricanARBP 52 by Nanjundayya 4. Studies were also conducted at SITRA by, Srikantaiah et al 5 on upgrading of Indian cottons like MCU I Rajapalayam Uganda, Sea Island Andrews, C02 etc. The cottons were combed to different levels of waste percent and the suitability and economics for particular end-uses were discussed. The contribution of fibre parallelisation and short fibre removal during the combing process towards improvement in yam quality was discussed by Bhaduri and Wakankar 6. The above studies have indicated from time to time the suitability of some of the indigenous cottons for superior end-uses. 87

4 TABLE: I FIBRE: PROPERTIES OF COTTONS USED IN THE: STUDY Giza 45 Baer Sorter Mean length mm 32.0 Effective length mm 38.0 Short fibre % 9.9 Micronaire value 3.4 Stelometer Bundle strength g/tex (0 gauge) 53.6 (1/8 in gauge) 35.2 Instron Tensile Tester Single fibre strength g Tenacity g/tcx 9.6 Maturity Mature fibre % 68 Half-mature fibre % 3 Immature fibre % 29 Maturity coefficient 0.81 Neps per gram 159 Sujata Sudan XG2VS Hybrid l.l MATERIALS AND METHODS In the present study two improved Indian cottons, viz., Sujata and Hybrid 4, were selected along with two imported var ;eties, viz., Giza 45 (ISKAT) and Sudan XG2VS). Their fibre prope11ies are given in fable I. They were processed under identical conditions in the T & S blow room consisting of horizontal opener, dust trunk and scutcher with three bladed beater, M.M.C. card, drawing frame with conventional 4/4 graduated drafting system (three passages), sliver lap former and Nasmith comber. The comber was adjusted to extract 8%, 10%, 12%, 14% and 16% waste in the case of Sujata and Giza 45. For Hybrid 4 and Sudan, the comber was adjusted to extract 8%, 12%, 16%, 20% and 24% waste. The combed slivers of different levels of waste extraction were processed through two passages of drawing with 4/4 graduated drafting system, slubber, inter and ring frame. Three counts were spun for each level of extraction. In addition, the carded sliver was also spun to the same three counts as control. The fibre and yarn tests, mentioned below, were carried out as per the standard procedures of the Laboratory 7. (A) Fibre Tests Raw cottons, carded slivers, sliver lap, 88 comber sliver and also the noils were tested to get the length parameters namely, mean length, effective length and short fibre percentage from the Baer Sorter patterns. (B) Yarn Tests The yarns spun from the combed slivers at different levels ofnoil extraction were tested for lea count ana strength using lea tester, single thread tenacity and extension on the Uster Dynamometer and yarn evenness as well as imperfections using U ster Evenness Tester with Imperfection Indicator. 3. RESULTS AND DISCUSSION 3.1 Fibre length parameter Analysis of fibre length data for combed slivers from the different cottons (Fig. 1 and Fig. 2) indicated that in general the mean fibre length of the combed slivers showed an improvement over that of the raw cotton and comber lap. Between the various levels of comber waste extraction, Giza 45 showed no marked increase in length with increase in comber waste. Hybrid 4 showed maximum improvement at 24% noil extraction while for Sujata and Sudan XG2VS po trend is noticed. The short fibre percent in combed slivers of different cottons was, however, lower The Indian Textile Journal, May 1976

5 20 ~ a: '" 10 ;;:... a:!i 5 II) 0 " SliVER LAP e COMBER NOll f%) FIG I GIZA < than that of the corresponding raw cotton and sliver lap and there is a general trend to improve at higher levels of noil extraction. 3.2 Yarn properties (i) Giza 45: Table 2 gives the yam test results for this cotton. The lea CSP values increased steadily with increase in comber waste, the maximum lea strength being E E cr--<!l SUDAN HYBRID 4 X62VS -' ~3&~~ 34 I z :! _..a---_-e-_ e-----g :,',[ 30 Sir--, I I I I ~.., a: 'J, '" j;: I- a: 0 X VI I SLIVER LAP " 'ck S I COMBER NOlL (Yo) FIG.2 observed around 14 to 16% combed yam. While a marked improvement in yam evenness over that of carded yam took place even around 8%, the U% improved with increase in waste extraction, the optimum being reached at about 14% level. It may also be mentioned here that the greatest reduction in neps took place only after about 14% waste extraction. Single thread tenac- 24 TABLE 2 YARN PROPERTIES FOR GIZA 4S Comber waste % Carded HOs Lea CSP I Single thread tenacity g/tex : Breaking elongation Uster unevenness % ', Ncps/lOOm H s Lea CSP g Single thread tenacity gltex Breaking elongation % Uster unevenness % Neps pci' 100m s Lea CSP Single thread tenacity g/tex Breaking elongation % Uster unevenness % Neps per 100m The Indian Textile Journal, May

6 ,~~..." YARN PROPEItTlES FOR SUJATA Comber waste % 0 Can\ed 6~h Lea CSP 2773 Single thread tenacity g/tex 18.2 Breaking elongation ~/o 6.6 Uster unevenness % 17.2 Neps per 100m s Lea CSP 2495 Single thread tenacity gltex 17.1 Breaking elongation % 6.0 Uster unevenness % 19.0 Neps per 100m s Lea CSP 2217 Sjng.le Inn-ad lenac.ily giu,y i5.5 Breaking elongation % 5.5 Uster unevenness % 20.0 Neps per 100m 'S : C6.3 [6.3 l6,z l6.z [6.S , ity values also reached their maximum at this level. (ii) Sujata: The yam test data for 60s, 80s, and loos are given for different levels of comber waste in Table 3. It is seen that ill general the maximum level of increase ill strength is achieved at 8% itself for all the counts compared to carded yarn strength. There is a marked improvement in U% and neps over the carded yam at 8% itself while the highest improvement is noticed aroumi 14% waste extraction. The single threa(i tenacity values were rather erratic, though II marked improvement of combed yam over the carded yam was noticed at 8% comber waste extraction itself. (iii) Sudan XG2VS: The results for this cot~ ton are presented in Table 4. A significantly marked increase in lea CSP of about 10 to 12% over carded yarn CSP was observed even at 8% comber waste extraction but no significant improvement took place at: higher levels. This observation seemed valid for U% as well. From considerations of improvement in neps as well as single thread tenacity 12 to 16% waste extraction seemed optimum for this cotton. 90 (iv) Hybrid 4: Appreciable improvement in lea CSP for this yam over the carded counts was noticed only at high levels of comber waste exraction of about 24% (Table 5). Both U% and neps decreased with increase in comber waste extraction, marked improvement being observed after 16% waste level. The single thread tenacity did not show any significant difference between different levels. 3.3 Comparison between Indian and imported cottons A comparison was made of the quality of yarns_ spun from Sujata and Giza 45 and from Hybrid 4 and Sudan XG2VS. The lea strength and tenacity of the combed Sujata yams are considerably lower than those of even the carded Giza 45 yarns. However, a study of the evenness and neps in the yarns shows that, while the combed Sujata yams are only slightly more uneven than the Giza yams, the former are considerably less neppy than the latter. Yams of 60s counts produced from Sudan XG2VS are also seen to be superior to 60s from S ujata in strength, tenacity and evenness but are considerably more neppy than the Sujata yams. Out of the four cottons studied Hybrid 4 produced The Indian Textile Journal, May 1976

7 TABLE 4 YARN PROPERTIES FOR SUDAN XG2VS Comber waste % Carded 50s Lea CSP Single thread tenacity gitex Breaking elongation ' Uster unevenness % Neps per 100mm s Lea CSP Single thread tenacity g/tex Breaking elongation % Uster unevenness % Neps per 100m S s Lea CSP Single thread tenacity g/tex ) Breaking elongation % Uster unevenness % Neps per 100m TABLE 5 YARN PROPERTIES FOR HYBRID 4 Comber waste % Carded 50s Lea CSP Single thread tenacity g!tex Breaking elongation % Uster unevenness % Neps per 100m s Lea CSP Single thread tenacity g/tex Breaking elongation % Uster unevenness % Neps per 100m s Lea CSP Single thread tenao.:ity g/tex Breaking elongation % Uster unevenness % ] ] Neps per 100m yams which are weaker than those of the other cottons but the least neppy yams. The poorer strength of the yams from the Indian cottons can be explained from their lower fibre length and strength as well as higher Micronaire value compared to the imported The Indian Textile Journal, May 1976 cottons. However, the neps in raw cotton were less for the two Indian cottons studied compared to the two imported varieties. 4. CONCLUSIONS Analysis of fibre length data for combed Fr '

8 slivers from the different cottons indicated that in general the mean fibre length of the combed slivers showed an improvement over that of the comber lap; between various levels of comber waste extraction, Giza 45 showed no marked increase in length with increase in comber waste. Hybrid 4 showed maximum improvement at 24% while for Sujata and Sudan XG2VS no trend was noticed. From the point of view of yarn strength and evenness, the optimum waste removal for the various cottons at the comber were found to be about 12 to 14% for Giza 45,8 to 12% for Sujata and Sudan XG2VS and 16 to 20% for Hybrid 4. While the yarn quality in terms of strength and evenness for the combed cotton yarns from Sujata and Hybrid 4 was poorer than that of the yarns from the imported cottons, the Indian cottons showed significantly lower neps, which would be a great asset in improving yarn appearance especially in fine counts. Acknowledgements The authors are thankful to their col- leagues in the Mechanical Processing and Quality Evaluation Divisions for their help in the spinning and testing of various samples. References 1. Richardson, R. P. and Ahmad, N., Technolo Bull. A-27 (1935). 2. Ahmad, N., Technol. Bull. A-44 (1938). 3. Gupte, V. V. and Iyengar, R. L. N., Technol. Bull. A-103 (1960). 4. Nanjundayya, C., Technol. Leaflet, No.41(1956). 5. Srikantaiah, G., Parthasarathy, M. S., and Ramchandran, M., 21st All India Textile Conf. Souvenir, p.83 (1964). 6. Bhaduri, S. N. and Wakankar, V. A., Proceedings of the 4th Technological Conference, ATIRA, BTRA & SITRA, p. 47 (1962). 7. Sundaram, V. and Iyengar, R. L. N., Hand Book of Methods of Tests for Cotton Fibres, Yarns and Fabrics,CTRL Pub. (1968) 92 The Indian Textile Journal, May 1976