Indian Journal of Fibre & Texti le Research Vol. 30, December 2005, pp. 468-476

Review Article

Garmen t d yej ng ] N Chakraborty", R udraj i t Pal & P R Megha

National Inst i tute of Technology, lalandhar 1 44 0 I I , India

Received 7 January 2005; accepled 3 1 March 2005

Garments arc e i ther prepared directly from processed fabric or the grey fabric i s converted i nto garmcnt fol lowed by processing. Out of these two. the latter has gai ned undue importance to tack le present day scenario more effect i vely . Thi s paper reviews the reasons behind this new chal lenge a s well a s other technical aspects related t o dyeing of garments .

Keywords : Dyeing, Garment. Garment accessories

IPC Code: Int. C l 7 D06P I I I OO, D06P3/00

1 Introduction Garment dyeing procedure has seemingly

proliferated itself in dyeing and fin ishing in recent years. Necessities of quicker fashion changes, reduction in final cost of production and a better aesthetic of dyed garment have enhanced the need for garment dyeing. Benefits of processing articles by garment dyeing procedure revol ve around quick response and inventory control 1 .2 , Processing lead time has considerably been reduced by a lmost 33% through garment dyeing techn ique, since colour is added late in the apparel process chain. Augmentation of easy monitoring techniques, replenishment of stocks with newer trend and fashion, reduced level of stock holding, complete computerized control and bar coding have recently emerged out as additional features of garment dyeing technique3-5 . Major interest in garment dyeing has developed to service domestic market with exceptional speed of response as means of differentiating from tradi tional colouration provided by exhaust and continuous processing3. 6.

Endeavour of clothing industry is to have maximum flexibil ity in respect of colouration. Earnest of proper colouration, flexibi l i ty and other features conforming to the latest but short-lived fashion trends demand garment dyeing for production of quality garments, meeting the demands of customers exactl/ . Methods of garment dyeing have successfully been implemented towards dyeing of cotton and cotton

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mixture articles - knitted or woven, with some recent developments in processing of wool len garments. However, garment dyeing of acrylics, polyamides. polyesters and their blends has also evoked in the recent past'. Current resurgence in garment dyeing from the point of view of garment processing industry has been because of the ( i ) short pipel ine necessary for quick response, ( i i ) reduced losses from dyed fabric waste, ( i i i ) no subsequent shrinkage. ( iv) lower energy, water and labour costs , (v ) reduced inventory, (v i ) abi l i ty to produce smaller batches, and (v i i ) production of uniformly dyed garments with no variation in shade at different parts of garmentsR•

Structure of garment dyeing sector comprises conventional fin ishers, laundries/drycleaners and garment dyers. Garment dyeing activities can be divided into four groups, viz, ( i ) fully-fashioned garment dyeing by major commission dyers and fini shers, ( i i ) cut and sew operations of garments covering woven and knitted fabrics dyed to high fastness standards, ( i i i ) dyeing of pure cotton goods for 'boutique' trade with low colour fastness - only suitable for hand washing, and ( iv ) washing, desizing and bleaching denim goods, leading to stone washing, snow washing and over dyeing or highlighting effects3• 9 . Cotton garments are suppl ied either in greige or prepared for dyeing forms. If the garment is in greige form, a full scour/bleach procedure is r�commended while for PPD (prepared for /dyeing) garments small amount of chemicals used to enhance garment manufacturing processes. such as softeners, antic uris and lubricants, must be removed to ensure level dyeing. Proper preparation eliminates 60-70% of

C H A KRA BORTY el at. : GARM ENT DYEING 469

dyeing problems. Garment processing concerns fabric manufacturing in greige mi l l s with apposite knowledge, cooperation, coordination and feedback between the greige mi l l s, preparation and fini shing departments. cut and sews operators and garment dyers . Otherwise. umpteen processing problems in garment s ize control . appearance and texture may evoke due to immoderate shri nkage, variation in yarn size/twist, warp spacing in woven and courseslinch in knits . Moreover, the problems of shade non­uniformity. differences in fabric preparat ion, viz . desizing. scouring, bleaching, and shri nkage properties must also be considered lo Stabi l ity of sewing threads. zips, buttons and other accessories are cruc ial considerations for subsequent garment processing.

2 Garment Dyeing Routes Since late seventies and eighties, there has been a

tremendous change in garment dyeing process, replacing traditional dyeing techniques where dyeing was carried out in fabric state prior to garment manufacture to associate better appearance and rheology to the merchandise. This has, to a great extent, enhanced the fashion look, appeal and comfort rendered by the merchandi se and reduced lead t ime by leaps' I J . 1 2. In garment dyeing of woven fabrics, continuous preparation and drying of fabric is succeeded by its delivery to the garment manufacturer and then cutt ing and sewing of it to produce stock. The sale of the retai l subsequent to dyeing and finishing of garment completes the process. Pretreatment of kni tted fabrics is carried out in pre­relaxed condition followed by relaxed drying and the ir deli very to garment manufacturer. Definitely this has an advantage of short lead time of about 2 weeks, and the abi l i ty to respond to point of sale feedback for stock repleni shment with dynamic response service has stimulated the growth of cotton garment dyeing in both woven and knitted fabrics as well as in multicomponent designs, incorporating woven and kni tted panels' 1 3 . For fully-fashioned cotton garment, dyeing is sl ightly different from the case for mult icomponent cut and sew garment. For knitted garment hlanks. dyeing i s preceded by make up and stock preparation. Garment passage continues ti l l i ts sale through intermediate drying and fi n ishing' . Alternately. the process adopted has its path in which make-up of fine gauge kni twear is in latter stage. This cons iderably increases lead t ime to 5-6 weeks from 2-3 weeks in the prior route.

3 Garment Dyeing TechniqueslProcesses In solvent dyeing technique, dyeing is eventually

carried out us ing chlorinated hydrocarbons, e.g. per­and tri -chloroethylene in the form of emulsions or 1 1 4 I I d ' solvents" . So vent acts on y as a me IUm to carry small quantities of water wherein dyeing process 1 • actually occurs' .

'Sancowad ' i s a foam-dyeing method developed for dyeing at a liquor ratio as low as 2 : 1 using foam as . d ff I ' . 3 1 5 1 (, I h' the medIUm for yestu app Icatlon . . . n t i s method. highly foami ng detergents are used to provide dense foam from low quantities of water (wi thin the machine) and water soluble dyestuffs are appl ied at very low l iquor ratios. Temperature is then raised to impm1 a fixation treatment stimulat ing to some degree a pad/fix system. Detailed study on the dyeing processes for various types of garments has a lso been d i sc losed 1 7-25

4 Garment Dyeing Machineries The cotton garment dyeing can be affected through

either trad itional side-paddle machines or rotary-drum machines.

4.1 Paddle Dyeing Machine

In the side-paddle machines, there is slow circu lation of both l iquor and garments in a large vat by means of a rotating padd le. These machines have re latively low product ivity and are slow in fi ll ing, heating, cool ing and draining, giving rise to longer lead t ime and requirement of higher l iquor ratio to fac i l itate c i rculation and levelness2G. 7 . One of the main l imitations of paddle dye machine is lack of cooling faci l i ties of dye bath which overcame in twin-paddle dyeing machines fitted with heat exchangers below the false bottom lG. 27, 28 . Completely enclosed overhead paddle machines, recently developed. consist of horizontal cylindrical vessel wi th doors along the top sides and horizontal paddle extending the length of machine parallel to and along the axis of the vessel . Perforated and closed steam pipes are situated beneath a perforated fal se bottom. It i"s also featured with a circu lating pump which withdraws hot l iquor from below the fal se bottom and injects it through the jet positioned along the side of the machine, just below the l iquor level to assist

f d 1 (,. 29. 7 movement 0 goo s .

4.2 Rotary Machine

Rotary machines consist of a horizontal perforated cyl inder, radially partitioned into three or four

470 I N DIAN 1 . FI BRE TEXT. RES . , DECEM BER 2005

compartments. rotating with periodic reversal i nside a stai n less steel box holding dye l iq uor. Goods are loaded i nto the cage through s l id ing doors i n the c i rcumference. These mac h i nes are gentle in their action. Recent deve lopments in these machines incl ude addition of hydro extractors, re- inforced glass doors, variable cage speed and operat ion on a programmed automatic cyc le i n which l iquor volume, t i me and temperature are fu l l y contro l l ed 1 6. 7 . 4.3 Recent Developments

With the advancement of t i me, s l owly the primi t ive laundry machineries. paddle and rotary dyeing mach ines, modi fied washer extractors. be l ly washers have been supplemented with automated and microprocessor control led machines. Some of the attri butes of ideal garment dyeing machines are the t i l ti ng mechanism, high temperature dyeing capabi l i ty and centrifugal extraction. Further controls of i ndirect heating and coo l i ng, variable speed control , water vol ume control and l i nt fi l ters have also been implemented. Garment dyeing which was earl ier a stepch i ld of wet process ing industry has advanced in to a un ique art incorporating in it newer designs and features. Some of these are: ( i ) low l iquor ratio, ( i i ) microprocessors for i mproved contro l l i ng, ( i i i ) heat exchangers, ( i v ) l i n t fi l ters, (v) centrifugal hydro extraction, ( v i ) easy sampl i ng, ( v i i ) pocketed drums, ( v i i i ) t i l t ing mechan i s m - for easy loading and un loading, ( i x ) high temperature option, (x) l arge load s izes, (x i ) cushioned suspens ion, ( x i i ) variable drum speed, and ( x i i i ) automatic balancing of drum'o.

During 1 970s, deve lopments in garment dyeing equipments were too many, v iz. ( i ) side paddle machi nes with variable speed paddles and of variable length ; ( i i ) 'smith drums' consisting of a rotating perforated drum norma l l y with four compartments l 6; ( i i i ) modified dryc lean ing u n i ts for solvent dyeing; ( i v ) dyeing mac h i nes with toroidal action developed original ly from the Pegg K-type scouring and mi l l ing machines for wool len garments. Liquor i s pumped up i nto a vessel contai ning garment carrier or p late and the l iquid i s deflected to the vessel c irc umference and then down i nto chamber with no mechanical assistance, movement being completely dependent upon the pumped action of water' l . Latest h igh temperature toroid dyeing mach ines work at l iquor ratio as h igh as 40: 1 to process 1 00% polyester fibre garments at 1 40°C (ref. 32); (v) dyeing in foam-in mach inery specifical l y designed for 'sancowad low l iquor process' . Other devel op ments inc luded a

centrifuging and drying operation as an in tegral part of dyei n g machine3 . 1 5 . However. advent of aqueous low l iquor dyeing machi nery with compromis ing l iquor ratios of approxi mately 1 0: I and tlex ib i l i ty to dye garments from a l l fibres led to obsolescence of this type of machi nery, and ( v i ) centri fug ing machi nes for rotary dyeing with i n tegral centrifugi ng and short processing t imes lends i tse lf ideal l y to the qu ick turnaround objecti ves i n today ' s market place' .

Rotary dye ing mac h i ne has evol ved out wi th considerable modifications every t i me in a more sophisticated and of modern version with the h ighl ighting features, viz. (i) optical bas ket configuration in which select ive pockets or bas kets are avai lab le whose configuration affects the degree and type of mechanical action appl ied to garment'. ( i i ) a n externa l c ircu lation which ensures maintenance of un iform temperature throughout the machine essential for cri t ical fibres, l i ke acry l ics. It invol ves c irculat ion of dye l iquor through a fi l ter to aid l iquor-goods i n terchange, thus compensat ing for reduced agitation when running the c y l inder at very low speeds. This protects the garment surface whi Ie a l l owing good penetration into seams and thick areas. An addit ional fi l ter unit is used for removing loose fibres and l i nts to prevent redeposit ion of the same on garment, (i i i ) h igh speed centrifuge system ensuring that the moisture content is reduced to minimum. prior to drying operation w i thout the need for add it ional hand l i ng and centrifuging in separate equi pments in dyeing stage3. Machi nes incorporated with centri fuge action have an added advantage of efficient rins ing in very short t ime, ( i v) sophist icated heat ing and cool ing w i th various means of accompl i s h i ng, e.g. d irect steam i njection i nto the dye l iquor and addi t ion of water direct l y to the machine su i table for s imple dyeing processes; indirect heati ng and coo l i ng by passing steam and water a l ternatel y through c losed coi l s at the base of machine ; i ndirect heat ing by means of a steam j acket around the body of the machine (coo l i ng is done ei ther directl y or indirect ly) ; and use of an external heat exchanger for indirect heat ing and coo l i ng. Heat exchangers may work with steam, o i l or h igh temperature hot water. Cool ing may be done by d irect addition of water or indirect ly through heat exchangers, (v) flex ib le control systems urge the use of automat ica l l y regulated functions. process paru:meters, microprocessor control on centrifug i ng machi nes ensuring use of VDUs flow measure ment. Technology requires advent of newer

CHAKRABORTY el al. : GARMENT DYEING 47 1

paraphernalias inc luding central control room with automatic addition of dyestuffs and chemicals from a central dispensing area, (v i ) special sampling port which results in complete inspection of garments during process without reducing l iquor level . Inspection of an entire garment from the batch lot at sampl ing stage ensures proper assessment of shade, seam penetration, degree of mil l ing and physical appearance, ( vi i ) easy loading/unloading is obtained through tilting mechanism in which the garment has to be loaded directly from overhead feed arrangements and unloaded without manual handl ing into a conveyor system, (v i i i ) variable cylinder speed during dye cycle ranging normal ly from 5 rpm to 35 rpIll . This al lows greater agitation at critical stages in dyeing process and less agitation to protect garment condition and max imize qual ity standards, ( ix ) high temperature processing of garments ensuring garment dyeing at temperatures up to 1 35°C, and (x ) dye l iquor recovery where spent dye liquor is transferred to a storage tank for reprocessing3 .

5 Selection of Dye for Cotton Garment Dyeing Depending upon end uses of garment, the direct,

fibre reactive. vat and sulphur dyes are used. Direct dyes, specifical ly classes A and B which have simi lar temperature of maximum exhaustion, are selected to ensure even application and higher reproducibility. At a dyeing temperature of 95°C, electrolyte is added to influence excess dye yield. Addition of calgon and a level ling agent is advisable for optimum results3 . Key application parameters for direct dyes involve dye b h h · . . d f 11 14 at ex austlon, f1 ns l llg an a ter-treatment" . . . . Special requirements of garment dyeing , viz. ( i ) good level dyeing properties, ( i i ) higher migration and diffusion properties to assist seam penetration, and ( i i i ) suitabi lity for short/automated process, have necessitated the use of reactive dyes26. This requirement is met particularly with less reactive, monochlorotriazinyl dyes with their high temperature application to optimize diffusion and migration, low reactivity to optimize level dyeing and ease of automation using linear addition profi les for both dye and al kali additions"

, 2(, . Further details of garment

dyeing with fibre reactive dyes have been discussed elsewhere3}. 35

'

Vat dyes have li mitations when severe chlorine fastness is required. Hot pigmentation technique is general ly employed in which the dye is dispersed as an insoluble pigment under alkaline conditions at 60-80°C. After a level ling period, dye is reduced to

leuco form and penetration into cotton fibre is affected. After flood rinsing at pH 10, reduced dye is oxidized back to insoluble form to achieve high wet fastness. Garment handling can be improved by cationic softener after-treatment} .

'.

Sulphur dyes represent a broad shade range, having good to excel lent wash and light fastness at relatively low cost as compared to other oyeing systems. B lack and medium to heavy shades of brown, blue and green are most commonly used ; the range does include some fairly bright colours as wel l . Nowadays. liquid sulphur dyes, cal led sodyesul liquids, are used which offer excellent performance and economy in exhaust dyeing. These are much advantageous than fibre reacti ve dyes as these have lower costs, shorter dye cycle, better cotton coverage, and much less salt with comparable fastness properties. ' Sandoz antioxidant B ' , a sugar based reduc ing agent, results equally high reduction as sulphides. This al lows an al l -in procedure without the controls needed for sodyesul liquids} '('. Presence of 20 ppm iron may al ter dye yield and shade ; presence of ea and Mg also poses same problem. Sequestering agents. such as Sandoz Sulfalox 100, can overcome problem of weak dyeings, poor crocking and streaks caused by the metal contamination36.

6 Pigment Dyeing of Cotton Garment Though pigments are used in printing and pad

dyeing since a long ti me, exhaust dyeing is a recent development. Being non-substanti ve in nature, binders are used to fix pigment on fibre surface. It was believed that the exhaust dyeing with pigments might not be practically possible due to low exhaustion and poor levelness. Development of suitable auxiliaries has lead to the induction of necessary affinity to fibres for pigments by pretreating textile for exhaust dyeing with pigments. Exhaust dyeing can be carried out in the fol lowing sequence: ( i ) prewashing, ( i i ) pretreatment, ( i i i ) exhaustion, (v) stone washing (optional ), ( v ) fixation, and ( v i) thermo-treatment37. 38 .

Impurities and contaminants are to be removed from garment through pre-washing to ensure best d · I 38 39 A . . I f d .

yelllg resu ts ' . crltICa part 0 yel llg sequence is pretreatment, where cotton is pretreated with a cationic compound to develop affin ity for pigmem -adequate uptake, and uniform adsorption of the cationic agent is essential for this purpose. During pretreatment, an ionic attraction is developed between pretreated fibre and aggregated pigment particles.

472 INDIAN 1 . FIBRE TEXT. RES . . DECEM BER 2005

Exhaust dyeing is carried out in a pigment dispersion fol lowed by binder fixation to improve fastness properties of garment as pretreated fibres so prepared have poor fastness property due to surface adsorption on ly. Stone washing. if required, is carried out before bi nder fi xation. Duri ng thermo-treatment, bi nder polymerizes to form cross l inkages to develop requi red fastness3�. Pigment dyeing procedure and related problems have a lso been disclosed 111 detai l l ll . .!Il.

7 Anti-corrosion Techniques Casual wears such as jeans are most ly incorporated

with meta l l ic components, l i ke zips, buttons, rivets, and labe ls made up of brass/iron/copperial uminumizi nc or magnesium. These can cause difficulties during garment dyeing. Peroxide bleaching is avoided to such prepared fabrics. Certain problems are encountered, such as dye resist mark or physical breakdown of the fabric, particularly in the area of direct contact with the metal component . Ferrous based materials have the risk of rust stai ns . Use of sequestering agent, such as EDT A, helps to prevent shade al teration due to chromophore sensitivity. Sandocorin 8 1 60 protects the metal from reaction8 . Most satisfactory option is the use of nickel plated brass as metal component. Use of inh ibitors based on phosphate ester/triazole gives the protection against metal component corros ion, a lthough care should be taken to avoid the retardation of dye build­Up3. 8

8 Novel Effects i n Garment Dyeing Unti l the advent of stone washing, garment dyeing

remained a rel atively sma l l and stable business . Where a worn-out or washed-out effect is desirable, the dyed material can be washed with or without stone addition before fixation}8. Oxidizing agents are appl ied to garments via stone soaked in reagents,

I · · d'fi ' f h I f 4 1 4? resu t l llg I n mo I Icat lon 0 t e co our 0 garment ' -. Colour receptivity of garments can a lso be modified using cross- l inking agents in finishing4 1 . Stone­washed cotton den im gives a fancy effect and a sty l i sh look. which has changed the demand for garment dyeing in today' s market43. ' Tee washing' i s another technique for creating unusual colouring effects, where dyed garments are stone tumbled with chlorine or sodium permanganate-impregnated rock for a prec i se period of t ime and then treated in a sodium bi sulphite bath. Different dyes, e.g. direct and reactive dyes. are affected di fferently by chlorine and sodium

permanganate. Some dyes are discharged or tota l ly destroyed by these chemica l s.w·.l6. Various techniques of garment washing, opt imization of parameters, enzymatic washing and various effects obtained including those for den im have a l ready been reported47.55 .

Special exhaust type fabric softeners for dyed garment after-treatments have a lso been developed1. These softeners are norma l ly added to the last cyc le to improve hand le of fi ni shed garment and he lp to restore some physical properties which might have been reduced by certain dye processes 56. I t is qu ite possible to cause a drastic change in look of dyed garments with foam fi nishing57, 58, post cure

59 . k I . f' . I (,() fl pretreatment , wnn F e res i stant I Il I S les , ock coating 6 1 or high frequency fixation('".

9 Woollen Garment Dyeing Wool len garments in knitted form such as sweaters

or hosiery are garment dyed. Recent deve lopment of woven wool len garment dyeing, such as rotary drum dyeing machines as wel l as side- and overhead-paddle machines has been reported 16. Machine washable fabrics are used to make garments which are to be dyed. Polyamide accessories used are a lso dyed with the same tone as that of wool len garment for complete matching. Common problems encountered during wool len garment dyeing are : (i) seam penetration, especial l y on pre-chlorinated garments where ch lorination within the seams may be uneven, ( i i ) fibre damage during prolonged dyeing. ( i i i ) reaching to the required level of colour fastness. and ( i i i ) cock l ing effect on the garment. Metal complex. mi l l ing acid dyes, reactive dyes and chrome dyes, if properly used, can minimize these problems 1 0 .

Specific dyeing auxi l iaries used in wool len garment dyeing are: ( i ) acid-donor system, ( i i ) low temperature dyeing, ( i i i ) after-treatment, and ( iv) anti­felting agentsG} . Informati ve reports have a lso been publi shed on the criteria-based dye selection6-l. 65.

Fe lting tendency of wool poses some problem on garmeot dyeing as i t leads to surface fe lting. Anti­felting protective agents are used in 'over-dyeing' to minimize surface distortionr" . Uses of anti-fel ting agents, l i ke Meropan NF ( Chemische Fabrik Ttibingen) and Nofelt WA (Tanatex), in wool len garment dye bath temporari ly protects unchlorinated garments during dyeing and are removed during

• • '1 66 A ' + 1 ' I d nnsmg" . ntl-le t l l1g agents are a so use successfu l ly in dyeing ch lorinated lambs wool garments. S tudies confi rm that the inclusion of I g/L

C H A K R A BORTY et at. : G A R M EN T D Y E I NG

Nofelt WA in dye bath l iquor i mproves wet bursting strength of untreated and chlorinated garment by reducing extent of chemical damage63.

In latest deve lopments, ' Dylan GRB ' and ' Hercosett" shrink-resi stant fin ishes have been introduced to meet the demand for machine washable wool len knit wears. These are based on appl icat ion of resins to the surface of wool fi bre after the latter has been modified by chlori nation. Some reactive dyes have been introduced for wool to get adequate fastness and are restricted to reds. yellows, browns

d · d' I I 1 (, an 1I1terme late co ours on y .

1 0 Polyester Garment Dyeing Pol yester fabric stabi I i ty, aesthetic appeal and

resistance to wear demand increase in use of textured polyester yarns for outer garments. Problems assoc iated with dye ing polyester garments by carrier method recommend the use of HTHP dyei ng, encouraging introduction of high-energy di sperse dyes of i mproved fastness properties 1 6. Comprehens ive reviews g ive further information on the use of carrier and auxi l i ary chemicals in polyester d . (, 7 6R I I d ' f d ' f' d ye lng ' . as we as ye1l1g 0 unmo I Ie polypropylene garment wi th acid leuco vat dyes!>!).

1 1 Quality Control Boost in export of ready made garments essent ia l ly

depends upon exceptional performance of garments. This requires maintenance of t ime schedule for shipments and production of h igh qua l i ty garments i n order to improve piece real ization . Production and marketing of h igh qual i ty garments thus depend upon their conformation to rigid standards of export, compl iance with the latest fashion changes, appropriate qual i ty control and sale demand. 'Price vs qual i ty ' i s a major aspect i n th is concern. Price of fin i shed garment chiefly depends upon three factors, viz. history of the fabric turned i nto garment. technical i nputs and use of appropriate processing

h· . 70 7 1 Th ' I' . mac 1I1enes ' . e major areas or qua l I ty control of garments are as fol lows:

1 1 . 1 Seams, Elasticized Areas, Waist Bands and scurrs

These areas must be fai rly loose, and seams should not be prepared taut otherwise this may lead to poor penetration of dyestuff in heav i ly swe l l i ng fibres. Possible remedy to this problem i s the appl ication of high temperature which results in better d iffusion, penetration and runn ing of c loth, fac i l i tating l iquid flow. This guarantees frui t ion of migration potential

and is essent ia l for mult i - layered seams or elast icized waists. Normal ly , a temperature of 95°C i s mainta ined b f I · +' f'

. R 7' e ore coo 1I1g lor Ixatlon ' -.

1 1 .2 Shrink Behaviour

Excessive or uneven shri nkage of garment where kni tted and woven fabrics are mixed, leads to seam puckering. It is essential to prerelax kn itted fabric and at the same t ime preshrink woven part. Thi s is done by ensuring various shrink proof treatments for high qua l i ty garments8. n .

1 1.3 Chafe Marks/Creases

These are defects developed part icularly on del icate garments due to mechanical stress i n drulll dyeing machine, which degrade the fi nal product . As a remedial measure. garments prone to chafe marks or p i l l i ng effect should be turned ins ide out and dyed in presence of non-foaming lubricant. Additional preventive measures may a lso be adopted by avoiding overloading of dyeing drum8. 72.

1 1.4 Accessories

Prudent choice of zips and meta ls accessories. such as buttons and studs, must be done to prevent their con-os ion or breakage. General ly, ferrous metals are avoided and preference for n ickel and its al loy i s made unless bleaching or react ive dyeing i s be ing carried out with high concentration of electrolyte or a lkal i . Choice for cellulosic buttons may lead to its undue breakage while polyester buttons are non dyeable and are used as neutral colours in coordinat ion wi th umpteen shades . Nylon buttons can be coloured in subsequent dyeing process with excess effort. R ibs of garment are genera l ly made of natural rubber or polyurethane such as Iycra. These materials , on the other hand, have their own disadvantages. Natural rubber is affected adversely in the presence of certain meta ls l i ke copper. In contrast, polyurethane artic les are degraded by strong oxidizing agents l ike chlorine. A solution to these traumas is achieved by coating the metal accessories wi th corros ion protection agent. Sandcorin 8 1 60 l iquid, an anionic organ ic corrosion inh ibi tor, i s an obvious choice as corrosion retardant. It prevents non-ferrous and white metals from oxidation and tarnishing by hi ndering the action of sens i t ive dyes onto the metal ions8 . 72 .

1 1 .5 Sewing Threads

Sewing threads must be endowed with des i rable properties, l i ke strength and fi neness to produce a neat seam and last for the whole l i fe of the produc{ 72

474 INDIAN J . F I B R E TEXT. R ES .. DECEM B E R 2005

Unmercerized cotton thread used in manufacturing of cotton garments produces a sol id dyed i nconspicuous seam. Polyester threads purposely enhance the effects in the seams due to their dye uptake resistance and mercerized cotton threads increase the dye uptake, resulti ng in darker appearance in shade. For cotton sewed garments meant for dyeing, it is not possible to switch-off directly from conventional ly spun polyester or core-spun threads to 1 00% cotton threads and retain the same seam characteristics. Equivalent seam strengths can be obtained using heavier cotton threads. S imi lar degrees of elastic i ty in seam can be obtained by increasing stitch density . Seam pucker resulting from thread shrinkage during garment dyeing can be avoided by slacker stitches on lock stitch and chain stitch operations'.

Selection of fibre for the preparation of thread depends on type of fabric to be sewed. Generally, a common selection is made for the thread used for fabric preparation and sewing. However, this is applicable mainly for cotton, as sewing threads made of other fibres do not possess affin ity for cotton dyes. This unarguably hikes the cost of garment manufactured and the production speed.

1 1 .6 Foreign Substances

Foremost object ive of efficient garment dyeing is i ts value addition. This objective caters need for adaptation of preventive measures to hinder value loss of the article. Protection of garments from stains due to oils, greases and other lubricating agents is thus critical . Other foreign substances, l ike s izes and resins containing additi ves such as elastomers and oil repelling agents could also denigrate the appearance

8 7" of garment . �.

1 1 .7 Interlinings

Purpose of interl in ings is to stabil ize and enhance the appeal of outer fabric. With post-dyed garments, celtain special properties has to be infl icted i nto the interl i nings to ensure better performance. Special properties i nherited by the interl in ings i nclude equivalent dye uptake by it as that of outer fabric. Moreover, the adhesive, bonding the outer fabric to the i nterl in ing, must remain i ntact during and after dyeing operation. Aftermath of dye sorption should not be adverse on colouration8. 72. 73. 1 1 .8 Care Labeling

Augmentation of fastness properties of dyed garments is essential for customers demand. Major attributes to be taken into consideration are: ( i )

d imensional stabi l i ty, ( i i ) wash fastness, and ( i i i ) rub fastness. To meet these parameters effecti vely, care labeling is achieved suitably which te lls the customers precautions to be adopted while cleaning the garment. These care labels are embel l ished with specific instructions with respect to method of washing. bleaching, dryi ng, ironing and suitabi l ity for dry cleaning. Various care label ing systems used are American, European, British and Canadians. 72.

Quality level in garment dyeing can be augmented through proper fabric and dyestuff selection to survi ve the rigors of processi ng, proper sizing, effective training of the staffs to ensure skil lful garment handling, good programming of dyeing equipments and i nnovations to increase production 74.

1 2 Recent Advancements in Garment Dyeing Sectors

Current resurgence in garment dyeing is probably because of the fidel ity of the article to recently evolved qual i ty control processes to adjudicate the 100pholes75. Certainly, the export of Indian ready made garment is becoming a more challenging job with the passage of time. This is reflected due to reversionary trend in A merican and European markets, restructuring of the world economy, disintegration of Soviet Union, emergence of China as a major world power, disturbances on internal and international front, increasing trade barriers, growing consumer awareness, rigid qual ity standards and recent ' multifibre agreement' fol lowed by the abdication of 'quota' system from January 2005 . ISO-9000 qual ity assurance certification and red l i sted chemicals are two new concepts required for enhancement of serviceabil ity and quality of product. Red li sted chemicals are hazardous pollutants which are accumulated on fibre during various processing phases76.

1 3 Advantages of Garment Dyeing There are several i nherent advantages in garment

dyeing, viz. ( i ) handling of smaller lots economical ly, ( i i ) unl imited selection of colour during dyeing, thus dyeing to order almost instantaneously, ( i i i ) a specific product can be dyed in any number of shades, thereby increasing productivity, ( iv) distress look with wrinkles, (v) ful l handle because of shrinkage duri ng dyeing, (v i ) quick turnaround at the retai ler' s counter, and (vi i ) abi l i ty to respond quickly to the changes in the colour taste of the fastidious and fickle customers 70.

CHAKRABORTY el al. : GARMENT DYEING 475

Cost justification of finished garment is an essential aspect of garment dyeing sector to add to its advantage. Major cost components in garment dy�ing are: (i) dye and chemical costs, varying considerably upon shades, fibre and dye chemistry ( i i ) uti l i ties primari ly based on the cost of natural gas to heat water and determine dye-liquor ratio, and (ii i ) d . , I b 77 78 eprec latlon or a our . .

1 4 Problems of Garment Dyers Most of the garments received by the garment

dyers are cut and sewn from previously prepared c loth which aggravates certain problems, l ike (i) garment is cut from more than one piece of c loth and these different pieces have been prepared differently, ( i i ) garment has woven and knit pieces sewn together, ( i i i ) garment has greige, prepared, bleached with optical whitener added. pieces all sewn together, and ( iv) a finish. e.g. softener, resin, etc . has been added 7CJ to the garment .

Preparation must be thorough, consistent and reproducible. This is extremely important since the cut and sew operation wi l l need to be oversized keeping in mind subsequent shrinkage. Variation in preparation wi l l result in inconsistency of final garment size after dyeing and drying.

The most common mistakes occur in garment dyeing are: ( i ) longer drying of goods resulting in wastage of energy and t ime, over drying and subsequent pi l l ing, ( i i ) excessive heating, creating wrinkles and at very worst resulting in melting of goods, ( i i i ) inadequate cool ing down, ( iv) insufficient loading to dryer, (v) not running dryer at constant production rate,(vi) unnecessari ly long load or unload times, (vi i) unclean filters, (vi i i ) non-maintenance of seal of dryer. and (ix) inaccurate production and cost f· 80 19ures .

1 5 Limitations In the backdrop of the advantages, there are certain

l imitations of garment dyeing. Even though the merits tota l ly outweigh the l imitations of garment dyeing, in the recent times i t has plunged out to be a sensation. It is required to discuss the demerits too. The l imi tations of garment dyeing can be summarized as ( i ) complicated dyeing, ( i i ) high percentage of seconds and (i i i) high dyeing cost70 .

1 6 Conclusions Commercial ly , garment dyeing is a rel atively

newer field of texti le processing. Ti l l the recent past,

there were no l arge scale ready made garment dyers in India and now it is time that large scale readymade garment manufacturers gradual ly switching over to garment dyeing after carefu l ly studying the pros and cons. The advantage of garment dyeing lies in its flexibi l i ty towards the fast changing market. quick and beneficial response and rapid turnaround. flexibi l ity towards dye shades, finish and lot sizes. Moreover, garment dyeing results in comparatively l esser rejections, requirements of lesser: inventory, smal ler capital investments and the chances of producing fancy and pri stine effects. Thus, with the widening of the prospects of garment dyeing with further developments from the technological point of view, the fashion trends have become more dynamic and pristine. The end of quota regime after 2004 wil l open u p new vistas for Indian Texti le Companies a s a repercussion already the stock markets are sniffing profits in the air. In 2004, the texti le shares have defin itely outperformed the indices by a safe margin. Certain ly, newer versions of garments have evolved with exaggerated qual ities and dynamic response. Thus, there would be an export bonanza for India in this quota free world.

References I Houser N E, Am Dyest Rep, 80 (5) ( 1 99 1 ) 1 8 . 2 Kramer F, Melliand Tex!ilber, 70 (7) ( 1 989) 225. 3 Bone J A, Col l ishaw P S & Kelly T D. Rev Prog Color. 1 8

( 1 988) 37 . 4 Natusch K & Comtesa Y P, Alii Dyes! Rep. 76 (5) ( 1 987) 3 1 . 5 Teichner A & Hol lywood N. Am Dyes! Rep, 76 (7 ) ( 1 987 )

38. 6 Gordon S, Proceedings. Conference all Carment Dyeing

(North Carol ina State Univ, Raleigh. USA). 1 987. 7 H i lden J. lilt Text Bull. Dyeing / Printing / Finishing, 34 (4)

( 1 988) 30. 8 Kamat S Y & Menezes E W, Colollrage. I I ( 1 993) 4 1 . 9 Scott K, Dyer. 1 7 1 ( 1 1 ) ( 1 986) 3 1 .

1 0 Gore D C. Tex! Chell! Color. 2 7 ( 3 ) ( 1 995) 37 . 1 1 Schrel l R, Proceedings. Conference on Canllen! Dyeing

(North Carol ina State Univ . Raleigh, USA). 1 987. 1 2 Col l i shaw P S & Glover B , Proceedings. Symposillm (Texti le

Federation of Canada. Sherbrooke), 1 986. 1 3 Coll i shaw P S & Cox K P, 1 Soc Dyers Color, 1 02 ( 1 0)

( 1 986) 298. 1 4 Brooks A G , Hosiery Trade 1, 8 ( 1 97 1 ) I 1 9 . 1 5 Lister G H, 1 Soc Dyers Color, 8 8 ( 1 972) 9. 1 6 Partridge H W. Rev Prog Color, 6 ( 1 975) 56. 1 7 Yob E. Melliand Textilber. 74 (6) ( 1 993) 564. 1 8 Harper R J & Lambert A H . Am Dyes! Rep. 77 ( 2 ) ( 1 988) 1 3 .

1 9 Reinhardt R M & Blanchard E J, Am Dyes! Rep. 77 ( I ) ( 1 988) 29.

20 Brissie R L & McAulay T. Am Dyes! Rep, 77 (7 ) ( 1 988) 28. 2 1 Riley S W & Jones C, Am Dyest Rep, 77 ( 1 0) ( 1 988), 23. 22 Dixon M W, Am Dyes! Rep. 7 8 (5) ( 1 989) 24.

476 I N DIAN J. F I B R E TEXT. RES. , DECEM B ER 2005

23 Harper R J & Lambert A H . Am Dyesl Rep. 78 ( 5 ) ( 1 989) 1 5 . 24 Hargraves R & Eissele E. AIIl Dyesl Rep. 80 (5) ( 1 99 1 ) 28.

25 Gurc D C & Settle J H . Am Dyesl Rep. 83 (5) ( 1 994) 24.

26 Col l i shaw P T. Col l inson S P & Parkes D T. Texl Prog. 1 9

( 2 ) ( 1 988) 1 8 .

2 7 Tcehnical repurt. AIIl Dyesl Rep. 6 7 ( 5 ) ( 1 987) 1 5 .

28 Mosinski E. Me/liolld Texlilber. 9 (3) ( 1 980) 252.

29 Kezarashi S K K. HI' Pal 1 ,248.366 ( to Japan Exlan Co), 1 969.

30 Bcsnoy R. AIIl Dyes/ Nep. 77 (5) ( 1 98 8 ) 56.

3 1 Swindall J L . Br Pm 1 .203 . 494 (to Samuel Pegg & Son Ltd ). 1 968.

32 Parr c' TexI Prog . 1 9 (2) ( 1 988) 47.

33 Kclley J J . Alii /)ycsl Rep. 76 ( I I ) ( 1 987 ) 44.

34 Houser N. Alii Dyesl Nep. 76 ( 1 0) ( 1 987) 25.

35 Bel l S J . Alii Dvcsl Rep. 77 (5) ( 1 988) 36.

36 Dixon M . Alii Dyesl Rep. 7 7 (5) ( 1 98 8 ) 52 .

37 Kass, .1 Soc Dvers Color, 74 ( I ) ( 1 958) 1 6.

38 Chong C L. Li S Q & Yeung K W, Alii Dyest Rep, 8 1 (5)

( 1 992 ) 1 7 .

39 Bender D J. Alii Dyesl Rep. 80 ( 5 ) ( 1 99 1 ) 24.

40 Walker B. Alii Dyesl Rep. 80 (9) ( 1 99 1 ) 56.

4 1 H arper R J & Lambert A H . Texl OCIII Color. 24 ( 2) ( 1 992)

1 3 .

42 Rudy K. Alii Tex! fill. 1 6 ( 1 0 ) ( 1 987) 36.

43 Etters J N , Alii Dyes I Rep. 83 (5) ( 1 994) 1 5 .

44 Mackie G M. Alii Dyesl Rep. 7 7 ( 8 ) ( 1 988) 40.

45 Tyndal R M. Alii Dyes/ Rep. 79 (5) ( 1 990) 22.

46 Etters J N. Alii Dyesl Rep, 84 ( 5 ) ( 1 99 5 ) 20.

47 Tech nical report. Tex! World, 2 ( 1 989) 6 1 . 48 Dey P, Mall Made Tex/ lndia. 3 ( 1 998) 1 29.

49 Shah D L, C/othsline. 6 ( 1 996) 53. 50 Chong C L & M a C W. Alii Dyest Rep. 85 ( I I ) ( 1 996) 1 5 .

5 1 Tyndal l R M . Tex! Chelll Color. 24 (6) ( 1 992) 23 .

5 2 Lantoo R , Oinonen A H & Shominen P. Alii f)vesl Rep. 8 5 ( 8 ) ( 1 996) 64.

53 Rucker J W. Freeman H S & HSO WhC1-I1Cen. Tex! Chelll

Color. 24 ( 1 0) ( 1 992 ) 2 1 . 54 H arper R J & Lambert A 1-1 . Alii Dyes! Nep. 82 ( 5 ) ( 1 993 ) 1 7 .

55 Kochavi D, Videback T & Ccdroni D. Ali i Dvesl /(ep. 79 ( 9 )

( 1 990) 24.

56 "Doc" Cheek, Alii Dyesl Rep, 76 ( 8 ) ( 1 98 7 ) 74. 5 7 Harper R J & Lambert A H , Am Dyesl /(ep. 80 ( 5 ) ( 1 99 1 ) 43.

58 Metzler R B. Am Dyesl Rep, 84 ( 8 ) ( 1 995) 8 5 .

59 Karnes S G. Am Dyesl Rep. 82 ( 9) ( 1 993) 74.

60 Brown R 0 & Fi l atex B . Alii D vesl Rep. 83 (9) ( 1 994) 1 06.

6 1 Technical report. Mellialld Texlilber. 9 ( 7 ) ( 1 980) 609.

62 Jola M. Melliand Tex/ilber, 9 ( I I ) ( 1 98 0 ) 93 1 .

63 Holt R R D . M arriott F W & Rush forth M A. Tex/. Prog. 1 9 (2) ( 1 988) I .

64 Lewis D M & Scltzer I, .I Soc Dyers Color. 88 ( 3 ) ( 1 972 ) 93.

65 Bel lhouse E, . I Soc Dyers Color. 9 1 (2) ( 1 975) 33.

66 I nternational Wool Secretariat. Texl f-foriz-oll . 6 (6) ( 1 986) 32.

67 M urray A & Mortimer K, .I Soc Dyers Color. 87 (6) ( 1 97 1 ) 1 73 .

6 8 Derbyshire A N . . I Soc Dyers Color. 88 ( I I ) ( 1 972) 389.

69 Etters J N. Alii Dyesl Rep. 86 (3) ( 1 997 ) 1 5 .

70 Rehani T R . Colourage. 7 ( 1 993) 3 1 .

7 1 Etters J N. Am Dyes! Rep. 85 ( 5 ) ( 1 99 6 ) 28 .

72 Kamal S Y & Menezes E W. Cololtrage . 6 ( 1 993 ) 2 5 .

73 Judd P J . TeXI Prog, 19 (2) ( 1 988) 52.

74 Stewart C W. Alii Dyesl Rep. 78 (5) ( 1 9 89 ) 22. 75 Etters J N , TexI Chem Color, 27 (2) ( 1 995) 1 7 .

76 Lal R A. Cololtrage, 8 ( 1 993) 27.

77 Reed W. Am Dyesl Rep. 76 ( I I ) ( 1 9 8 7 ) 3 5 .

78 Besnoy R . Am Dyesl Rep. 7 8 ( 5 ) ( 1 989) 30. 79 M u rphy J M, Am Dyest Rep. 76 ( I I ) ( 1 987) 4 1 .

80 Diedl ing M. AII1 Dyesl Rep, 7 8 (9) ( 1 989) 86.