Effect of mass of seed cotton and its lint quality on yarn properties
N M Imayathamizhana, K Raghunathan & M R Srikrishnan
Department of Textile Technology, A C College of Technology, Anna University, Chennai 600 025, India Revised received 6 February 2006; accepted 13 April 2006
Reduction in variation of fibre properties within particular fibre groups to get excellent fibre and yarn qualities from the available raw material and categorization of seed cotton prior to ginning with respect to their mass has been explored. For appropriate utilization of raw material to produce yarn of a particular quality, the manually picked seed cottons were grouped with respect to their mass measured with an accuracy of 0.001g. The grouped seed cottons were then ginned on roller gin with four different roller and beater speed combinations and fibres of each group were tested using AFIS and HVI as per the standard procedure. The yarn samples were produced as per the sequence of process used for carded cotton yarn.
The separation of the seed cottons with respect to their mass results in the categorization of fibres with respect to their physical properties. The higher mass of seed cotton results in superior fibre properties and vice versa. Similar to fibre properties, a significant enhancement in yarn quality is also observed, particularly in the samples ‘101-150mg’ and ‘151- 200mg’ for both 50s and 60s Ne count yarns.
Keywords: Cotton, Ginning, Lint quality, Yarn quality IPC Code: Int. Cl.8 D02G3/00
1 Introduction
To reduce the variation in fibre properties within a particular fibre group for better fibre, yarn, and fabric qualities from the available raw materials, the process of categorization of seed cotton on the basis of their mass before ginning must be incorporated in the existing sequence of processing cotton in yarn production. The carded yarn process is sufficient for achieving better process performance and yarn quality because the correlation between upper quartile length and mass of seed cotton is significant. This categorization process is not only helpful in categorizing fibres with respect to their physical properties but also helpful in the categorization of seeds with respect to their mass during ginning. This helps in getting better and heavier seeds for planting and thus in reducing deterioration of fibre properties during ginning. The mass of seed significantly affects the properties of fibres.1 Ginning rate in double roller gins is 8-10 times lower than that in saw gin.2 The neps in card sliver from saw ginned cottons are lower by 30 - 60 % as compared to that from roller-ginned cottons, even though the saw ginned lint samples have higher neps.3 Therefore, from a single cotton variety, it is possible to produce at least three different ranges of yarn counts with excellent quality and improved process performance when categorized fibre groups
(groups 1, 2 and 3) are processed separately with varying process parameters from ginning to spinning (carded process because fibres are categorized with respect to their length by categorization of seed cotton).
In the present work, the influence of mass of seed cotton and its fibre properties on the quality of yarns produced has been studied. The importance is given to the influence of mass of seed cotton, and its fibre properties on yarn quality because the nature of the mass distribution in kapas decides the range of variations in fibre properties within a particular fibre group. Therefore, the categorization of seed cotton with respect to its mass before ginning in the existing sequence of cotton yarn manufacturing (as a carded process) will help the textile industry in achieving an improvement in appropriate utilization of raw material for producing yarn and fabric of a particular quality without using the combing process.
2 Materials and Methods
2.1 Materials
MCU-5 cotton variety was grown and harvested at Irrulappatti village in the state of Tamil Nadu, South India. From the harvested seed cotton, five different samples were separated, namely ‘immature sample’
and ‘normal sample’ (usual practice followed for collection, preparation and ginning), and with respect to mass of seed cotton ‘below 100 mg’, ‘101-150 mg’
and ‘151-200 mg’. All these five samples were
______________
aTo whom all the correspondence should be addressed.
Formerly known as M Tamil Selvan.
E-mail: imayathamizhan@annauniv.edu
processed separately from ginning to ring spinning as per the existing known sequence of processing. The three different samples with respect to mass of seed cotton, namely ‘below 100 mg’, ‘101-150 mg’ and
‘151-200 mg’, obtained from ginning under four different combinations of speeds of beater knife and roller in roller ginning machine were processed separately (Table 1).
2.2 Process up to Winding
All the fibre samples were processed uniformly from ginning to winding and carded yarns of 50s and 60s Ne were produced. The process parameters used for 50s and 60s Ne carded yarns from blowroom to spinning are as follows:
Blowroom Lap hank : 0.001609 Carding Sliver hank : 0.160 Doffer speed : 20 rpm Draw frame (two passage)
Sliver hank : 0.160 Number of doubling : 8 Delivery speed : 300 mpm Simplex
Roving hank : 1.50 (for 50s Ne) and 1.80 (for 60s Ne) TM : 1.08 (for 50s Ne) and 4.3 (for 60s Ne) Spindle speed : 900 rpm (for 50s Ne) and 19000 rpm
(for 60s Ne) Spinning
Spindle speed : 18500 rpm
TM : 4.10
2.3 Fibre and Yarn Testing
Fibre samples were tested using high volume instruments (HVI) and advance fibre information system (AFIS) as per the standard procedures.
Similarly, the yarn samples were tested using Cascade, Premier IQ and Premier Tensomaxx 7000 instruments and standard procedures.
3 Results and Discussion
3.1 Mass of Seed Cotton and its Fibre Properties
Five samples, separated from MCU-5 variety are shown in Table 2. Significant difference in fibre properties is observed between the samples. The
increase in mass of seed cotton results in increase in spinning consistency index (SCI), fibre micronaire value (MIC), strength in g/tex (STR), fibre length (LEN), uniformity (UNF), count strength product (CSP), reflectance value (Rd), upper quartile length (w) (UQL), fineness in millitex, maturity ratio (MR) and a corresponding reduction in short fibre index (SFI), yellowness value (+b), short fibre content (SFC), immature fibre content in % (IFC), nep in contents/g (NEP) and seed coat nep in um (SCN) values, thereby resulting in enhancement of fibre properties.
Therefore, without categorization of seed cotton with respect to their mass, the variation in fibre properties within the particular sample increases. This limits the improvement in the fibre properties because the normal sample in the study shows poor properties as compared to the samples ‘101-150 mg’ and
‘151-200 mg’ even though the normal sample does not include fibres from unopened cotton bolls but includes fibres of other samples. The fibres of immature samplea show significantly poor properties (Table 2) as compared to other samples but in the end it comes closer to the sample ‘below 100 mg’.
Variations in fibre properties are significantly higher within a single variety. Categorization of seed cotton with respect to the mass of kapas helps in reducing variation in fibre properties. Fibres with particular mass of kapas must be processed separately from ginning to spinning for a particular yarn count and for a particular application. This will ensure improvement in the quality of product and the process performance without using the combing process because among the fibre properties of comber lap, sliver and noil, the noil (removed fibres) consists of short and immature fibres of low mass per unit length and high neps. The comber fibre properties, collected from spinning industry, are shown in Appendix 1. It is therefore clear that the separation of short fibres can be easily achieved by categorization of seed cotton with respect to its mass.
3.2 Mass of Seed Cotton and its Ginned Lint Quality
The range of differences in SFC, SFI and NEP (content/g) within a particular mass of seed cotton (particularly of lower mass, below 100 mg) is
Table 1 — Ginning machine specifications Combination
speed
Speed of beater knife
opm Speed of roller rpm
1 600 73 2 800 97 3 900 110 4 980 120
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aThese cotton bolls were collected from one or two days prior to boll burst open. It is common that for every picking period, there are some numbers of unopened bolls due to improper picking.
These bolls are collected and processed separately.
significantly (at 95% level) higher with respect to combination speeds of beater knife and roller. The results are shown in Table 3. Therefore, grouping of seed cotton with respect to its mass and the change in ginning process are essential for getting corresponding improvement in yarn quality.
3.3 Effect of Fibre Properties on Yarn Quality
The properties of yarn have been discussed in terms of only two parameters, namely yarn tensile strength and appearance. The discussion of tensile properties of yarn includes Avg STR, CSP, tenacity (RKM), elongation (ELG), breaking force and breaking work.
Similarly, the appearance properties of yarn include U%, thin places, thick places, NEP (total imperfections) and hairiness.
Excellent changes in yarn properties are observed with respect to fibre properties (Table 4) for both 50s and 60s Ne yarns. Significant improvement in yarn quality is also observed particularly in the samples
‘101-150mg’ and ‘151-200mg’ for both 50s and 60s
Ne yarns as compared to the normal sample. The incorporation of the categorization of seed cotton with respect to its mass prior to ginning produces excellent improvement in yarn quality as well as performance in processing.
Very significant correlation is noticed between fibre and yarn properties for both 50s and 60s Ne yarns (Table 5). Fibre properties which are enhanced due to an increase in mass of seed cotton, namely SCI, MIC, STR, LEN, UNF, CSP, Rd, +b, UQL, SFC, fineness, IFC, MR, NEP (contents/g) and SCN (um), significantly influence the yarn tenacity and appearance. The fibre properties, namely SCI, MIC, STR, LEN, UNF, CSP, Rd, UQL, fineness and MR, correlate positively with tensile properties and negatively with appearance. Similarly, the fibre properties, namely +b, SFC, IFC, NEP (contents/g) and SCN (um), correlate negatively with tensile properties and positively with appearance. The other groups of samples, namely ‘below 150 mg’ and
‘above 100 mg’, also show significant difference in
SCI – Spinning consistency index, MIC –Fibre micronaire value, STR –Strength in g/tex, LEN –Fibre length, SFI –Short fibre index, ELG –Elongation, CSP –Count strength product, CG –Colour grade, Rd–Reflectance value, +b –Yellowness value, UQL –Upper quartile length (w), SFC –Short fibre content (n), IFC –Immature fibre content, MR – Maturity, and SCN – Seed coat nep.
Table 3 — Mass of kapas and corresponding fibre properties with respect to combination speeds of beater knife and roller by AFIS and HVI Fibre properties by AFIS Fibre properties by HVI
Combination speed UQL
mm
SFC NEP um
NEP contents/g
SCN um
SCN contents/g
SCI MIC MR LEN mm
UNF SFI STR g/tex
ELG
% Below 100 mg
1 27.0 30.7 676 286 1340 17 138 2.66 0.76 25.93 48.0 8.5 19.9 5.2 2 26.8 33.8 692 226 1304 7 130 2.75 0.77 26.70 46.8 8.8 20.6 5.3 3 27.9 26.4 707 229 1320 13 129 2.74 0.77 26.81 47.2 6.0 20.6 5.4 4 28.8 27.6 675 228 1075 4 135 2.75 0.76 25.31 48.1 7.2 19.3 5.2
100 – 150 mg
1 27.9 22.1 740 101 1034 15 134 3.88 0.83 26.81 47.7 5.4 22.9 5.0 2 28.2 23.5 704 81 1663 4 134 3.92 0.83 26.19 47.9 6.1 22.4 5.2 3 27.3 23.6 758 68 1454 7 131 3.81 0.82 26.05 47.8 5.8 21.6 5.2 4 27.0 23.7 702 75 1575 2 135 3.86 0.83 26.52 47.9 6.7 22.4 5.1
151 – 200 mg
1 28.3 18.9 632 38 1100 2 123 4.83 0.88 28.09 46.8 6.5 24.1 5.0 2 28.7 16.6 759 48 1708 5 133 4.45 0.85 26.48 48.3 5.9 22.6 5.1 3 28.3 20.8 735 53 1556 9 131 4.79 0.87 27.14 48.0 6.3 23.5 5.1 4 28.5 17.1 654 46 900 3 124 4.79 0.87 26.80 47.5 6.6 22.8 5.1
Table 2 — Mass of kapas and corresponding fibre properties
Table 5 — Correlation between fibre and yarn properties Property Average
strength
CSP RKM ELG
%
Breaking force, gf
Breaking work, kgfm 50s Ne yarn count
U% Thin Thick Nep Total imperfections
Hairiness
SCI 0.99 0.98 0.91 −0.17 0.91 0.82 −0.97 −0.98 −0.93 −0.92 −0.93 −0.72 MIC 0.80 0.84 0.70 −0.60 0.70 0.46 −0.79 −0.74 −0.81 −0.84 −0.83 −0.70 STR 0.95 0.93 0.84 −0.11 0.84 0.80 −0.88 −0.94 −0.82 −0.77 −0.80 −0.75 LEN 0.95 0.97 0.88 −0.45 0.88 0.70 −0.94 −0.93 −0.94 −0.92 −0.94 −0.82 UNF 0.91 0.93 0.84 −0.32 0.84 0.68 −0.93 −0.88 −0.92 −0.96 −0.95 −0.65 ELG −0.23 −0.27 −0.47 0.21 −0.47 −0.35 0.47 0.32 0.55 0.61 0.58 0.14 CSP 0.98 0.96 0.88 −0.14 0.88 0.82 −0.92 −0.97 −0.88 −0.83 −0.86 −0.76 Rd 0.98 0.96 0.91 −0.16 0.91 0.84 −0.94 −0.98 −0.90 −0.85 −0.88 −0.78 +b −0.88 −0.89 −0.59 0.54 −0.59 −0.43 0.69 0.76 0.64 0.57 0.61 0.87 UQL 0.83 0.86 0.82 −0.43 0.82 0.63 −0.89 −0.82 −0.91 −0.93 −0.93 −0.66 SFC −0.56 −0.57 −0.78 0.17 −0.78 −0.67 0.77 0.66 0.83 0.85 0.84 0.40 Fineness 0.78 0.74 0.74 0.34 0.74 0.77 −0.79 −0.78 −0.72 −0.78 −0.77 −0.27 IFC −0.85 −0.83 −0.76 −0.18 −0.76 −0.75 0.83 0.83 0.77 0.83 0.81 0.38 MR 0.88 0.86 0.90 0.13 0.90 0.87 −0.94 −0.91 −0.91 −0.94 −0.94 −0.45 NEP, um 0.11 0.05 0.52 0.48 0.52 0.71 −0.35 −0.35 −0.38 −0.29 −0.32 −0.08 NEP, content/g −0.99 −0.97 −0.94 0.21 −0.94 −0.85 0.97 0.99 0.94 0.89 0.92 0.80 SCN, um −0.89 −0.92 −0.66 0.56 0.66 −0.43 0.79 0.78 0.76 0.78 0.78 0.74 SCN, content/g −0.48 −0.48 −0.35 −0.21 −0.35 −0.29 0.48 0.39 0.43 0.61 0.54 −0.09
60s Ne yarn count
SCI 0.94 0.89 0.86 −0.33 0.88 0.54 −0.96 −0.91 −0.96 −0.96 −0.97 −0.83 MIC 0.80 0.79 0.52 −0.73 0.49 0.03 −0.90 −0.71 −0.90 −0.91 −0.90 −0.77 STR 0.90 0.87 0.94 −0.04 0.94 0.75 −0.88 −0.94 −0.88 −0.83 −0.87 −0.84 LEN 0.96 0.94 0.78 −0.50 0.77 0.37 −0.99 −0.89 −0.99 −0.99 −0.99 −0.88 UNF 0.88 0.82 0.65 −0.65 0.67 0.20 −0.95 −0.78 −0.96 −0.99 −0.97 −0.76 ELG −0.37 −0.30 0.03 0.76 −0.06 0.40 0.37 0.07 0.38 0.51 0.42 0.10 CSP 0.93 0.90 0.93 −0.13 0.94 0.69 −0.92 −0.95 −0.92 −0.89 −0.92 −0.85 Rd 0.95 0.92 0.93 −0.16 0.94 0.68 −0.93 −0.95 −0.93 −0.91 −0.94 −0.85 b+ −0.80 −0.85 −0.84 0.10 −0.74 −0.60 0.87 0.94 0.85 0.74 0.82 0.96 UQL 0.86 0.81 0.57 −0.71 0.59 0.10 −0.91 −0.72 −0.92 −0.93 −0.93 −0.73 SFC −0.68 −0.60 −0.35 0.66 −0.44 0.04 0.65 0.41 0.66 0.77 0.70 0.38 Fineness 0.65 0.54 0.61 −0.25 0.71 0.41 −0.67 −0.61 −0.69 −0.73 −0.71 −0.44 IFC −0.72 −0.62 −0.65 0.34 −0.72 −0.39 0.77 0.70 0.79 0.81 0.80 0.56 MR 0.82 0.72 0.68 −0.42 0.78 0.38 −0.83 −0.72 −0.85 −0.90 −0.87 −0.58 NEP, um 0.29 0.24 0.34 0.36 0.49 0.49 −0.04 −0.13 −0.04 −0.13 −0.10 0.08 NEP, contents/g −0.98 −0.94 −0.92 0.22 −0.94 −0.63 0.95 0.95 0.96 0.94 0.96 0.86 SCN, um −0.81 −0.81 −0.64 0.58 −0.58 −0.20 0.94 0.82 0.94 0.90 0.92 0.87 SCN, contents/g −0.29 −0.16 −0.06 0.72 −0.14 0.26 0.46 0.21 0.49 0.55 0.50 0.16
Table 4 — Mass of kapas and corresponding yarn properties
Table 6 — Mass of seed cotton and corresponding yarn properties
both 50s and 60s Ne yarn quality (Table 6). No relationship is observed between fibre and yarn elongation. Similarly, there is no relation found between fibre properties [NEP (um) and SCN (contents/g)] and yarn properties.
4 Conclusions
4.1 It is suggested to consider the mass of seed cotton during ginning, so as to avoid the deterioration in fibre quality with modified ginning parameters.
4.2 The mass of kapas significantly affects both the fibre and yarn properties. The immature sample shows poor results and samples ‘101-150 mg’ and
‘151-200 mg’ show improved properties when compared with the normal sample. Therefore, only a limited range in mass of kapas must be allowed for the production of a particular yarn.
4.3 Consideration should be given for the incorporation of process. For example, categorization of kapas with respect to its mass prior to ginning within the existing sequence of cotton yarn manufacturing process need to be incorporated to minimize deterioration in fibre and yarn quality.
4.4 Fibres from lower mass of kapas may be kept separately and used for producing either yarns of coarser counts or for any other applications, such as preparation of microcrystalline cellulose, and for making paper.
4.5 The process ‘categorisation of kapas’ prior to ginning will help to achieve correct and effective utilization of raw material for producing particular quality of yarn and fabric.
Acknowledgement
The authors are thankful to the Joint Managing Director and other officials of M/s Sambandam Spinning Mills Limited, Salem, Tamil Nadu, India, for their help in producing and testing the requisite samples.
References
1 Tamil Selvan M & Raghunathan K, Indian J Fibre Text Res, 31 (2006) 346.
2 Jadhav S B, Vancheswaran S, Vizia N C & Iyer K R K, Indian J Fibre Text Res, 28 (2003) 377.
3 Cellamani K P, Parthasarathy N & Arindan Basu, Asian Text J, (July 2003) 75.
Appendix 1 — Comber fibre properties (MCU-5) Fibre properties by AFIS Comber
material UQL mm
SFC Fineness m.tex
IFC
%
MR NEP um
NEP contents/g
SCN um
SCN contents/g
Lap 34.5 28.4 155 5.7 0.90 641 96 1093 5
Sliver 35.5 11.2 168 4.9 0.96 617 32 0 0
Noils 16.9 79.9 127 9.4 0.73 663 604 1016 26
UQL – Uper quartile length (w), SFC – Sort fibre content (n), IFC – Immature fibre content, MR – Maturity, SCN – Seed coat nep.
