Indian Journal of Fibre & Textile ResearchVol. 22, June 1997, pp. 84-88

Effect of different blending methods and blending stages on properties ofMilange yarn

B K Behera, P K Hari, Seema Bansal & Rahul Singh

Department of Textile Technology, Indian Institute of Technology, New Delhi 1\0 016, India

Received 19 July 1996; revised received 13 November 1996; accepted 12 December 1996

The effect of different blending methods and blending stages on milange yam characteristics has beenstudied. Both dyed and grey fibres with different degrees of opening and cleaning were mixed atblowroomldrawframe stage to improve the varieties of milange yarn. The extent of fibre damage and theuniformity of fibre distribution have also been evaluated. Separate processing of grey and dyed fibres atblowroom and card provides better yam quality with respect to evenness and imperfections. Minimumprocessing of major grey fibres with drawframe blending of dyed component has been suggested to achieveimproved yarn strength. However, blowroom blending has been found to be more beneficial from shadeuniformity point of view. Drawframe blending can be used in special cases for production of fancy milangeyam.

Keywords: Blowroom mixing, Drawframe mixing, Fibre damage, Milange yam, Relative unevennessindex

1 IntroductionAmong all the fibres used for apparel manu

facture, cotton is considered as one of the best fibresdue to its superior physical and mechanical proper-ties such as tensile properties, moisture absorbency,surface characteristics and its compatibility withmany other natural and synthetic fibres':", Thetechnological development has enabled the textileindustry to produce numerous types of yams andfabrics with special appearance by varying structureand product mix'. These special effects in yarns andfabrics can be introduced right from mixing stage inblowroom and more conveniently in subsequentprocesses such as drawframe, ringframe, doublers,sectional warping and final weaving stage. Thespecial effect in yam and fabric could be generatedby selecting the fibre mixture of various propor-tions. Milange refers to a hosiery yam produced -bymixing dyed and undyed cotton fibres (sometimesviscose also). The process for spinning milange yamis yet to be established because of the fact that theimpurity of cotton is not fully extracted at a singleprocess. In addition to this, repetition of mechanicalaction to the fibre may cause damage to fibre whichsubsequently influences yam and fabric properties 4

.

The present study is aimed at investigating the effect

of bending methods on properties of milange yamprepared by dyeing the cotton fibre after differentstages such as blowroom, card and combing andthen mixing dyed fibres with grey fibres atblowroom and drawframe. The extent of fibredamage and uniformity of fibre distribution has alsobeen evaluated.

2 Materials and Methods2.1 Materials

Cotton fibres (type, F414; effective length, 26mm; and tenacity, 0.289 N/tex were used as suchand after dyeing with Procian M dye at 80°C for 90min using HTHP method. 24% dyed and 76% greycotton fibres were used for both drawframe andblowroom mixing.

2.2 Methods2.2.1 Yam and Fabric Preparation

Six different yam samples were prepared usinggrey and dyed fibres. In each sample, either 3

different blending method or a different blendingstage was introduced. Table 1 shows the spinningsequences for all the yam samples prepared.

Two drawframe passages in case of blowroornmixing and three drawframe passages for drawframemixing were used.

CT-1

Tab

le1-

Se

quen

ceof

yarn

spin

ning

for

vario

usbl

ends

(T-2

RAW

COT'

l'ON

+BL

ENDE

R~

DYED +

PRE

OPEN

ERRA

WCO

TTON

\."

BLOW

ROOM •

CARD

ING

.+

D.RA

WFRA

ME~

SPEr

.VFR

AME

••RI

NGFR

AME

CT-

4 RAW

COTT

ON+

BLOW

ROOr

--l

••CA

RDIN

G

RAW

COTT

ON••

BLOH

ROOM

toCA

RDIN

G • DYEDIN

SLIV

ER•

PRE

OPEN

ER;,

BLOW

ROOM •

CARD

ING ---

--. DRAW

FRAM

E•••

SPEE

DFRA

ME••

RING

FRAM

E

RAH

COTT

ONBL

OJRO

OM+

CAHD

ING

DYED

I~JS

LIVE

RFO

RM

•PR

EOP

ENER

RAW

'-..~

BLOW

ROOM

CARD

'NG

~DH

AWFR

AME

SPEt

DFRA

MEt

RING

FRAM

EC

T-5

HAH

COTT

ONRA

WCO

TTON

••

BLOW

ROOM

BLOW

ROOM

CARJ

ING

CAR~

ING

COMl

ING

COMt

ING

DYED

!IN

SLIV

ER;'

ORM

PRE

OPEN

ER --. BLOW

ROOM

..,CA

RDIN

G••

DRAW

FHAM

E••

SPEE

DFRA

ME+

RING

FRAM

E

COTT

ON

(T-3

RAH

COTT

ONRA

H•

BLOH

HOOM

••CA

RDIN

G ••DY

EDIN

SLIV

EH

•PR

EOP

ENEH '-.

'BLO

WRO

OM ••CA

RDIN

G +DR

AWFR

AME

+SP

EEDF

RAME

.-RI

NGFR

AME

RAW

COTT

ON+

BLOW

ROOM •

CARD

ING •

COMB

ING •

DYED

INSL

IVER

FORM

+PR

EOP

ENER

*BL

OWRO

OM •CA

RDIN

G ---

COTT

ON•••

BLOW

ll.O

OM••

CARD

ING

FOR~

/txl m ::t: E ~ ;:, ,...

CT-

6 RAW

COTT

ONBL

OWRt

OOM

+CA

RDIN

G+

COMB

ING

-e i':l ~ ; o 'Tl ~ ? ~ C) m ~ ~

-.

DRAW

FRAM

F. •SP

EEDF

RAME

+RI

NGFR

AME

00 VI

86 INDIAN J. FffiRE TEXT. RES., JUNE 1997

Plain knitted fabrics were prepared on a circularknitting machine using the above six yam samples.

2.2.2 Tensile PropertyTensile properties of all the yam samples and the

fibres extracted from these yam samples weredetermined on Instron tensile tester according toAS1M procedures. Lea CSP of yam sample wasmeasured on a Good Brands lea strength testingmachine.2.2.3 Unevenness and Imperfections

Yam unevenness and imperfections wereevaluated on UT-3 using standard methods.

2.2.4 Computer Colour Matching

An ACS Spectrosensor 11 spectrophotometerinterphased with IBM personal computer was usedto measure colour value (KIS), reflectance value ancwhiteness index. Kubelka-Munk equation, widelyused in colour measurement, relates reflectance (R)to the absorption coefficients (K) and (S) for auniformly coloured sample illuminated withdiffused light.

KlS = (I-R)/R

Therefore, the KlS value of dyed sample minusthat of the undyed sample was taken to compare dyeuptake of different samples. This test showscomparative shade variation among differentsamples.

2.2.5 Relative Unevenness IndexRelative unevenness index (RUI) indicates

coefficient of colour variation within a sample.Reflectance value was measured at eight differentplaces at a definite wavelength interval of 100mthroughout the visible spectrum (400 om - 700 om)and then the coefficient of colour variation wascalculated.

3 Results and Discussion3.1 Effect of Blending Methods and Blending Stages3.1.1 Tensile Properties

Table 2 shows that the values of CSP for samplesCTt, CT2 and CT6 are higher than those for othersamples. The difference in case of CTl and C1:"6issignificant at 99% confidence level; however, thedifference between CTt and Cf4 is significantat 95% confidence level. Simultaneously, the CSPvalues of samples CT3 and CT5 are very low.As the samples Cfl and CT2 are prepared bymixing fibres at blowroom and the raw and dyed

fibres go through blowroom and card only once,CSP and tenacity of these samples are towards thehigher side. This is due to the fact that there is noexcessive carding action. The CSP values of CT3and CT4 are lower than those of CI'I and CT2because these samples (CT3 and CT4) are cardedtwice and this might have induced fibre damage atcard which is reflected by low CSP value. In case ofCT6, combed slivers of dyed and grey fibres aremixed at drawframe. So, due to combed fibres andsingle carding of combed fibres, CSP of this sampleis high. But in sample CT5, initially the combedsliver is prepared and then this sliver is mixed withdyed sliver at blowroom. Hence, these fibres gothrough the card twice and this might have causedexcessive fibre damage and hence poor yarn CSP. Itmay be inferred that wherever there is a doublecarding action on fibres, a decrease is observed inCSP of yarn presumably due to mechanical damageof fibres which is examined subsequently.

3.1.2 Yam Evenness and ImperfectionsTable 3 shows that the yam imperfections (thick

places, thin places and neps) are substantially low incase of CT4 and CT6. In both cases, the respectiveslivers are mixed at drawframe. Opening andcarding of dyed and grey fibres are done separately.Due to dyeing, fibres get clustered and stick to eachother. Opening and carding of dyed fibres becomevery difficult if they are processed with grey fibres.If grey fibres are taken in sliver form (carded orcombed) then processing becomes even more

Table 2- Tensile properties of yams

Sample Count CSP Tenacity Strain TPI TMcode Ne N/tex %cn 30.56 1813 0.1120 4.13 22.13 4.09cn 29.32 1714 0.1102 4.60 22.01 4.06CT3 30.96 1563 0.0936 5.06 22.23 4.01CT4 29.30 1674 0.1021 4.76 22.13 4.09CT5 31.21 1526 0.0927 5.12 21.50 3.93CT6 32.54 1826 0.1140 4.13 21.21 3.84

Table J-Unevenness and imperfections of yams

Sample Count CV% ImperfectionsllOOO mcode Ne (-50%) Thin Thick Neps

places places

(+50"10) (+200"10)

cn 30.56 22.58 433 606 1889cn 29.32 21.94 316 562 1696CT3 30.96 23.09 481 648 1550CT4 29.30 21.09 262 446 1172CT5 3\.21 22.76 308 652 1956CT6 32.54 19.38 126 255 954

BEHERA et al.: PROPERTIES OF MILANGE YARN 87

difficult. This may be seen in case of CT3 and CT5.Due to poor opening of dyed fibres, cluster of dyedfibres forms imperfections. The same problem isobserved with samples CTI and CT2. Therefore, itcan be concluded that for less imperfections greyand dyed fibres should be processed separately onblowroom and card. Separate actions optimize fibreopening and then these slivers should be mixed atdrawframe, because after draw frame no openingaction takes place. Extensive care should be takenduring opening and carding of dyed fibres.Conditions should be optimized for this becausethese fibres are in sticky form. Therefore, it isadvisable to carry out proper preopening of dyedsliver in milange yam production.

3.1.3 Fibre DamageTable 4 shows that the fibres extracted form CT3

and CT5 yam samples have low tenacity comparedto those extracted from CI'I, CT2, CT4 and CT6samples. It is also observed that fibres from samplesCTl, CT2, CT4 and CT6 have more or less samestrength. In all these samples grey fibres go throughblowroom and carding machines only once. So,there is less chance of fibre damage in the greycomponent. In case of CT2 and CT4, dyed fibres arecarded twice and their bulk in yam is very low (only24%). Hence, no significant decrease in fibretenacity is observed. But in case of CT3· and CT5there is a drastic fall in fibre tenacity. In thesesamples, the grey as well as dyed fibres areprocessed in blowroom and card twice. They arefirst passed through blowroom and card to maketheir respective slivers which are then mixedtogether in blowroom and, hence, they got againblowroom and carding action. This extra blowroomand carding action probably causes damage to thefibres which is reflected in the form of a decrease infibre tenacity.

No perceptible change in fibre length is observedamong the six samples. This may be due to the factthat the fibres have been affected to the extent whichhas resulted in loss of tensile properties. They areinfact not separated to pieces which usually occurswhen the fibres are stretched being caught by twonips.

3.2 Computer Colour MatcbingThe degree of fibre mixing by different blending

methods is evaluated by estimating colour value andcoefficient of colour variation with the help of

computer controlled colour matching system. Theresults for comparative colour values are given inTable 5 and level of shade variation within a sampleis shown in Table 6. In Table 5 the values representthe colour mismatch. Hence a pair of colours, whichare colorimetrically matched, has a calculated valueof zero for the total colour difference (DE). Thevalue of DE increases as the degree of colourmismatch increases. The results clearly show that notwo samples are perfectly colorimetrically matchedbut their level of mismatch is varying. SamplesCU, CT3 and CT5 have more or less same level ofmismatch compared to sample cn which is takenas standard. But sample CT4 and CT6 have a greaterlevel of mismatch than other samples. This meansthat their colour value is different than those of othersamples. Reason for these is that samples CU, CT3and CTS are prepared by mixing at blowroom. Butsamples CT4 and CT6 are mixed at draw frame andin this mixing dyed and grey fibres could not mix

Table 4- Tensile strength of fibres

Sample Tenacity Effectivecode N/tex length

mmCTI 0.2856 26CT2 0.2680 25CT3 0.2098 24CT4 0.2815 26CT5 0.1764 25CT6 0.2950 26

Table 5-Comparative shade of each sample

Sample DE KlScode

CTI 1.668CT2 0.90 1.664CT3 \.32 1.667CT4 2.28 1.734CT5 1.11 \.641CT6 \.88 \,712

DE: Colour differenceKJS: Colour value

Table 6-Level of shade variation within a sample

Sample code

CTICT2CT3CT4CT5CT6

RUI value

0.16550.14460.13450.26560.09240.3595

RUI: Relative Unevenness Index

88 INDIAN J. FmRE TEXT. RES., JUNE 1997

properly. Dyed sliver produces a special type ofcolour line effect depending upon its position. ondrawframe. The higher KlS value for Cf4 and Cf6samples shows that these samples have compara-tively darker shade. This can be due to theappearance of dyed fibre cluster in yam which givesa feel of darker shade. This proves that while mixingof grey and dyed slivers at drawfame, we cannot gethomogenous mixing of fibres. Moreover, drawframemixing produces cluster of dyed fibres in the yarn.RUI values indicate coefficient of colour

variation in a given sample (Table 6). Less is thevalue, better the colour distribution. If RUI value ismore, the intensity of colour varies in that sample.Results show that coefficient of colour variation isless in samples en, Cf2, Cf3 and CfS and veryhigh in samples Cf4 and Cf6. Hence, in samplesCl'l , Cf2, Cf3 and CfS the distribution of dyedfibres is very uniform and both grey and dyed fibresgot mixed properly as a result of blowroom mixing.However, high values for Cf4 and Cf6 samplesindicate that at some points the intensity of colour ismore than that at other points. This is due topresence of coloured fibres in cluster form in theyarn, thereby increasing the colour intensity at thatpoint. This shows that in drawframe mixing, bothgrey and dyed fibres are not mixed properly andhence, colour variation in a sample is high in case ofdrawframe mixing.

4 ConclusionsBlending methods and blending stages

significantly influence milange yam properties.Highest CSP has been achieved by mixing grey anddyed slivers at drawframe by giving only onecarding passage. Excessive mechanical action byrepetitive blowroom and carding causes fibredamage and loss in fibre tenacity, resulting in loss ofyarn tensile properties. Better evenness and lessimperfections are achieved by separate processingof grey and dyed fibres at blowroom and cardbecause fibres are more sticky and are in the form ofcluster. Better shade uniformity is produced byblowroom mixing as both grey and dyed fibres getbetter chance to mix homogeneously than thatindicated by drawframe mixing. Hence, blendingmethods and blending stages should be decidedtaking into account the end-use of the yam. Pre-opening of dyed component should be carried outproperly to improve blend homogeneity and betteryam quality.

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2 Balls W L, Studies of quality in cotton (Macmillan,London),1928,80.

3 Pednekar A, Maharnbare S, Decker B V & Chandan Saha,Man-Made TextIndia, 31 (1988) I.

4 SaIhotra K R, Spinning of man-made and blends in cottonsystem (Textile Association of India), 1989.