Textile dyeing & Process

Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular chemical material. … In dyeing, it is applied to the entire textile.

1. 1
Textile Dyeing& its Process.

2. 2
Basic Textile Terms and Definitions
Dyestuffisorganicorinorganicsubstances
whichcanabsorblightandreflectsomelightsto
showcolor.Actually,thedyestuffiswater
solublesubstances.
Pigmentisasubstancethatcanabsorblightand
reflectsomelightstoshowcolorbutitiswater
insolublesubstances.Normallyitisusedfor
printing(withthepresenceofbinder)ormass-
colorationofthesyntheticfibers.

3. 3
Stainingisanunpleasantofdyeinginthearea
thatwedonotwant.Exhaustionofthedyestuffto
thefibersisasfollows:
1.Movingofdyestufffromdyebathtosurfaceof
thefiber
2.Adsorptionofthedyestuffintothesurfaceof
thefiber
3.Diffusionofthedyestuffintothecenterofthe
fiber

4. 4
Classification of Dyestuffs
Dyestuffscanbeclassifiedbymanymethodsas
follows:
1.Theirionic(e.g.cationic,anionicandnon-ionic)
2.Theirfiberdyeabilities(e.g.oncellulosic,
protein,polyester,polyamideetc.)
3.Theirnames(e.g.acid,direct,disperse,reactive,
basicetc.)
4.Theirchemicalstructures(e.g.azo,
anthraquinone,stilbeneetc.)
5.Theirorigins(e.g.natural,synthetic)
6.Theircolors(e.g.red,green,blacketc.)

5. 5
DyeingProcessescanbeappliedinmanystages
suchas
1.Mass-colorationofthemoltenfibers
Thismethodisfordyeingthemoltenfibersor
plasticchipsortextilepolymerswithpigment
dyes.Afterthat,themoltenorpolymerswill
extrudefromaspinnerettoformfibers.
Normally,thesyntheticfibersareaddedwith
whitepigmentinordertogiveahidingpower
(non-seethroughfabrics).
Advantage:giveexcellentfastness
Disadvantage:verydifficulttoclean

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2.FiberDyeingisthemethodofdyeingfibers
beforeblendingwithothercolorstogivefancy
yarnsorfabrics.
Note:Thisisusedforspecialpurposesonly.
3.YarnDyeingisthemethodofdyeingyarnsin
formsofhanksorpackagesdyeing.Thiswill
giveScottish’sstylefabrics,carpetwithmany
colorsandstyles.
Note:Thisisusedinhandloomweavinginthe
NorthernandNorth-easternpartsofThailand.

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4.FabricDyeingisthemethodafterweaving,
knitting,ornon-woventomakefabrics.Thisis
verypopularmethodofdyeingasthedyed
fabricswillbeprocessedfurthertogarment
industriesveryeasily.
Dyeingformsofthefabricdyeingcanbeused
in2ways:
1.Openwidthformusingthefabricstospread
withoutanycreasesanddyethem.
2.Ropeformusingthefabricswiththeformlike
arope(manycreasesandlooklike“arope”)

8. 8
Somepeopleclassifyinto:
1.ExhaustionProcess
Thismethodisusinglotofwaterasshownin
“LiquorRatio(ratiobetweenwaterandgoods)”
Thisshouldimmergethegoodsintodyesolution
foralongtimeinordertoletthedyepenetrate
intothegoods.Thiswillleadtoproducemore
wastewaterthanthecontinuousprocess.
Advantage:inexpensive,noneedtotrainthe
workertolookafterandrunthemproperly.
Disadvantage:lotsofwaterneeded,veryslow
process(60-120min/batch.)

9. 9
2.ContinuousProcess
Thismethodisdesignedbyputtingdifferent
machineryintoasequencesothatitcanproduce
thedyedfabricinonepass.
Advantage:veryfastprocess(10-100m/min),
smallamountofwaterintheprocess.
Disadvantage:veryexpensive,needtotrainthe
workertolookafterandrunthemproperly.

10. 10
6.GarmentDyeing
Thismethodisthelastprocessofthedyeingof
goods.However,thepenetrationofthedye
solutionmaynotbecompletelypassedtothe
fiberssuchasbetweentheseams,buttons,
zippersetc.Normally,itisusedforlingerie,
socks,sweaterdyeingetc.

11. 11
Name of DyestuffsFibers that can be dyed
Acid Silk, wool, polyamide,
leather
Basic Acrylic
Direct Cellulosic, viscose
Disperse Acetate, triacetate,
polyamide, polyester, acrylic
Reactive Cellulosic, viscose,
protein
Vat Cellulosic
Sulphur Cellulosic

12. 12
Factorsthatgivesomechoicesofthedyestuffs
1.Cheap
2.Non-toxic
3.Compatibletootherdyesandchemicals
4.Highcolorstrength
5.Betterbrightness
6.Betterfastness
7.Goodlevelnessonthematerials

13. 13
DyesforCellulosicFibers
DirectDyes(Anionic)
Theycanbedyeddirectlyoncellulosicfibers.
Withoutthepresenceofsalt,whenthefibersare
immergedinwater,itwillshowanioniccharge
whichrepelsthedyes.Addingsaltintothedye
bath,itwillreduceanioniconthefiberssothe
dyescangetcloserandadsorbintothefibers.
Advantage:cheap,easilydyedonfibers
Disadvantage:poorwetfastnessandsomedyes
havepoorlightfastness.

14. 14
TextileAuxiliaries
1.Salt-reducenegativechargesonthefibers
2.Water-dyeingmedia
3.FixingAgent-enhancewetfastnessbutusually
reducelightfastness
DyeingConditions(Exhaustion)
dyeing100oCx30-90min
fixing60oCx20min
(Continuous)
pad-->dry-->steam-->wash-->soap-->dry

15. 15
Reactive Dyes (Anionic)
Theycanbedyedoncellulosicfibers.The
mechanismisnearlythesameasdescribedin
Directdyes.
Advantage:highwetfastnessduetocovalent
bonding(ChemicalBonding)betweenfibersand
dyes,easilydyedonfibers
Disadvantage:Expensive

16. 16
Dyeing Conditions
1.ContinuousProcess
1.1Pad-dry-bake
Thisisveryeasymethodforcottonorcotton
blendsfibers.
1.2Pad-dry-Pad(Chemical)-Steam
Thiswillgivebrighterandmoreintensecolorthan
method1.1.
1.3Pad-batch
Thiswillputthegoodsintothedyesolutionand
squeezewith2rubberrollerstogetridofexcess
waterandthenbatchatroomtemperaturefor1-2
days.

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2.ExhaustionProcess
Thismethodwillbeusedinsmallfactory.Dyeing
conditionswillbe40-80oCfor30-90min
dependingtothetypesandstructuresofthedyes.
TextileAuxilaries
1.Salt-reducenegativechargesonthefibers
2.Water-dyeingmedia
3.SodaAsh-excitethedyetolinkwiththefibers
withcovalentbonding.Therefore,itenhanceswet
fastness
4.FixingAgent-enhancewetfastnessforheavy
shadebutusuallyreducelightfastness.

18. 18
VatDye(Anionicwhensoluble)
Thedyeisnamedfromthecontainer(Vat)that
usedforrottingthedyewithalkalisolution.This
crucialprocesswillreducethedyefrominsoluble
tosolubledye(suitableforexhaustioninthe
cellulosicfibers).Nowthemanufacturercan
synthesizeman-madevatdye.

19. 19
DyeingProcess
1.Dissolvedyeintowater(insolubledye)
2.Vattingprocessbyreducingtheinsolubledyein
alkalicondition.(solubledye)
3.Absorbintofibers(solubledye)
4.Afterdyeing,oxidizethedyewithoxidizing
agent(insolubledye)
5.Washandsoapthegoods

20. 20
DyeingConditions
1.ContinuousProcess
1.1Pad-dry-Pad(Chemical)
Thesolutionofthedyeispreparedwithout
addingreducingagenttoensurelevelingdyeing.
Afterthat,thegoodsarepassedtochemicalbath
toreducethedyeintosolubledyeandfixwithin
thegoods.Oxidizingagentisaddedtothegoods
andconvertedtoinsolubledyes.

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1.2 Pad-oxidize-pad-oxidize (many times)
This will put the goods into the dye solution and
squeeze with 2 rubber rollers to get rid of excess
water, oxidize with the air and then immerse into
the dye solution again and again to allow the dye
penetrate into the goods.

22. 22
TextileAuxilaries
1.Salt-reducethenegativechargesonthefibers
2.Sodiumhydroxide-adjustpHtothedyeing
bathandmakethesuitableconditionsforreducing
agent.
3.Sodiumhydrosulfite-reducingagentforthevat
dyes.
4.Water-dyeingmedia
5.Oxidizingagents-(Hydrogenperoxideor
AceticacidorAir)oxidizethesolubletoinsoluble
dye

23. 23
SulfurDye(Anionicwhensoluble)
Thedyeingprocesshasthesameprocessas
describedinthevatdyeexceptthatusingSodium
sulfideinsteadofSodiumhydrosulfide.

24. 24
DyesforSyntheticFiber
DisperseDye(polyester,nylon,andacetate)
(non-ionic)
Thedyeisnamedfromlesswatersolubleand
normallyappearedindispersioninwater.The
dyeshowsnochargeduetothegroupspresented
inthedyemolecules.
DyeingConditions
Insoluble
dye in
water
Less water
soluble
Water insoluble
in polyester
fibers

25. 25
1.ExhaustionProcess
1.1Atboilwithcarrier
Thisprocessissuitableforacetatefiberandpale
shadepolyesterfiberdyeing.Carrierisan
auxiliaryforswollenfiberinordertoallowmore
dyesabsorbingin.Nowtheuseofcarrieris
reducedbecauseitmaybeacarcinogen.
1.2At130oCwithoutcarrier
Withthehightemperature,thedyeswillbe
dissolvedintosmallermoleculesandthevoidin
fiberstructurewillbeopened.Thiswillgive
heavyshade.

26. 26
Textile Auxilaries
1.DispersingAgent-makethedyesolution
stableanddisperseinthedyebath.
2.Acid-adjustpHtothesuitableconditionfor
thedyebath.
3.Carrier-swellthefiberanddissolvethedyeto
makethedyegettingintofiber.
4.Levelingagent-makemorelevelingdyeing
(somewillhaveadverseeffectonslowerdyeing)
5.Water-dyeingmedia

27. 27
ReductionClearing(R.C.)
Afterdyeingprocess,thedyedgoodsshouldbe
removedexcessdyesonthefibersurface.R.C.
willgivehigherwashingandrubbingfastnessof
thedyedgoods.
Usingalkalisolution,sodiumhydrosulfideand
dispersingagent,theR.C.willbedoneat60oCx
20min.
Note:Donotusemorethantherecommended
temperaturebecausesodiumhydrosulfidecanbe
decomposed.

28. 28
AcidDye(Anionic)
Thedyeiscalledacidbecauseitneedsacidic
dyeingcondition.Itcanbedyedonprotein
fibers(silk,wool,otheranimalfibers)andon
polyamidefibers.
Acidicconditionwillgivethefibersshowing
positivecharge.Asthenegativechargewill
attachdirectlytopositivecharge,andpenetrate
intothefibers.
Dyeingconditions
100oCx30-60min

29. 29
TextileAuxiliaries
1.Levelingagent-forlevelnessdyeing
2.Retardingagent-forinhibitingthedyenot
attachtofiberstoofast
3.Acid-adjustthedyeingconditionandmakethe
fiberstoshowpositivecharges
4.Water-dyeingmedia

30. 30
BasicDye(Cationic)
Thedyeshowspositivecharge.Normally,the
dyecanbeappliedonwool,silkand
polyacrylonitrile(acrylic).
DyeingConditions
100oCx30-60min

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Textile Auxiliaries
1.Levellingagent-forlevelnessdyeing
2.Retardingagent-forinhibitingthedyenot
attachtofibrestoofast
3.Acid-adjustthedyeingconditionandmakethe
fibrestoshownegativecharges
4.Water-dyeingmedia

32. 32
Dyes Dyeing Condition (pH)
Acid (Wool)2-4, 4-6, 6-8 (depends
on types of dyes)
Acid (Nylon)4.5-5.5, 6-7 (depends
on types of dyes)
Basic 3.5-4
Direct 7.0
Disperse (Polyester)5-6
Disperse (Acetate)6.5-7.0
Disperse (Triacetate)4.5-6.5
Reactive 7.0 (Exhaustion)
11.0 (Fixing)

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Thank you
AnilKumar,Lecturer
DepartmentofTextileDesign,FOD,
PanditLakhmichandraStateuniversityof
Performing&VisualArts,Rohtak
[email protected]
Mob.No.-9729138649