DYEING AND POLYESTER AND COTTON BLENDS

DYEING OF POLYESTER AND COTTON BLEND

ssSUBMITTED TO:

DR. M.L.GULRAJANI SUBMITTED BY:

ASHISH DUA(2012TTF2406) IIT DELHIashisdua@gmail.com1

Classification of the methods for dyeing of P/C blendExhaust dyeing method or batch dyeing method- This is again classified in the following three groups-a. Two bath dyeingb. One bath one step dyeingC. One bath two step dyeing method Thermosol Dyeing method -It is again classified in to two groups-a. Continuous dyeing-b. Pad batch process (semi-continuous)Note-In continuous dyeing process may be single bath or double bath.

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EXHAUST DYEING-Two bath dyeingThis is the process in which we have to dyed first polyester part in the HTHP beam dyeing machine or HTHP jet dyeing machine and the cotton part is dyed in the jigger machine.Batch processMachine used for dyeing of polyester part- i) HTHP Beam dyeing machine( First commercialized HTHP machine) ii) HTHP jet dyeing machineMachine used for dyeing of cotton part-Jigger dyeing machine

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PROCESS ROUTE P/C BLEND DYEING-

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MACHINE FOR POLYESTER DYEING-HTHP beam dyeing machine-No need to explain the whole process of dyeing in beam dyeing machine. Only some important points we will discuss about it-Advantages & features:Loading and unloading of the fabric is easy and time of dyeing is short.Dyeing in open width form.Most suitable for those fabrics that might crease, extend or abrade when dyed in machines where the fabric is in motion.Not appropriate for compact fabricsDe-aeration is essential to avoid paler dyed spots.A wetting agent helps to eliminate air bubbles within the fabric roll.6

Recipe used HTHP dyeing

Disperse dye- X%(depends upon the shade)Dispersing agent-1g/lSequestering agent-1-2g/l(If required)Defoamers -.5 to 1g/lLevelling agent-.5 to 1 g/lWetting agent- .5g/lAcetic acid-enough to get ph=5-6

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Flow of the liquor usually in the in-to-out direction, but it can be reversed. Out-to-in flow can compress the material causing flattening and glazing, particularly on the inner layers.

Material stationary and liquor is moving.

Batching is very important, during batching tension should be uniform and optimum.

M:Lratio is 1:10

Both cloth and yarn can be dyed on this machine8

HTHP BEAM DYEING MACHINE-

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Disadvantages of beam dyeing machine-Fabric of different width can not be dyed together on a single beam.The dyed fabric may be display moir effect if it is tightly due to shrinkage.Uneven dyeing may occur if the beam is fully loaded ,as the dye liquor has penetrate several layers of fabric.10

JET DYEING MACHINE-

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JET DYEING MACHINES-

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HTHP jet dyeing machineThe jet dyeing machine is an extension of the HPHT winch dyeing machine. Jet dyeing machine developed by BURLINGTON Industries and first machine developed in 1963 by Gaston country Machine co. of U.S.A Features:Both material and liquor is moving.Dyeing in rope form.Fabric speed usually 200-250mt/minThe jet dyeing can usually operated up to 1400c under high pressure and having capacity capable of dyeing 100 to 150 kg of fabric at a time

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Chemicals added AcidsBuffersSequestering agentAnticrease agent Defoamers Levelling agent

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DEVELOPMENT IN JET DYEING MACHINE-Soft flow jet- slow motion of fabric. Suitable for knitted fabricSuper jet dyeing machine- M:L is 1:1Aerodynamic jet dyeing machine Jet created by mixture of air + waterM:L is 1:1 , drain out at a 130cMulti-nozzle sot flow jet dyeing machine

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Advantages of jet dyeing machine:

Fabric of two different width can be dyed at a time so that two lots can be combined together for dyeing.No special batching device is required for winding the fabric as in beam dyeing.There is no flattening effect or uneven dyeing on the fabric as in beam dyeing16

Disadvantages:

There is possibility of entanglement of light-weight fabric during dyeing.Loose fibres removed from the fabric may get redeposited on the fabric surface as well as on the interior of the jet dyeing vessel, this problem does not arise in beam dyeing.Yarn can not be dyed in a jet dyeing machine whereas it can be dyed in a beam dyeing machine.PROBLEMS-1.Foaming problem2.Oligomers problem3.Rope marks17

Machine used for cotton dyeing-Jigger dyeing machineOpen jigger or closed jigger dyeing machine-Closed jigger specially for vat dyeing.Liquor is stationary and fabric is moving.500 t0 1000 meter of fabric is processed in one time.M:L ratio in jigger dyeing machine is about 1:5. Usually take 10 min. for each passage18

One bath two step dyeing-One-bath dyeing processes ,using both the dyes such as following in the same dye bath.1. Disperse and vat dyes.2. Disperse and reactive dyes.3. Disperse and direct dyes.

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DISPERSE/REACTIVE DYEING SYSTEM-

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Disperse/vat dyeing system-

Typical dyeing recipe Disperse dye-X% Vat dye-Y% Dispersing agent-.5-1% wetting agent-.5-1% pH 4-5 with acetic acid (30%)Procedure-Prepare the bath with dispersing agent, wetting agent and acetic acid + treatment for 10-15min at 50-60c then + disperse and vat + dye for 10-15min + raise temp up to 130c in 60-90 min.

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Procedure continued-After PET part dyeing cool to 80c for proper levelling then add NaOH & Na2S2O 4 + dyeing 15min + cooling to 60c + dyeing for 30 min. for better exhaustion Rinse with cold water + oxidation with H2O2 for 15min at 50c + Rinsing with cold water + Soap at 95 C for 25 min using 2 g/l Lissapol D + Hot and cold rinse and then final wash off.Only vat dyes which are stable up to 130c can be used for this process.

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One bath two step dyeing method-All vat dyes may be used for the one bath high temperature process provided that the dyes are finely divided enough. The IK vat dyes are not preferred because the dye liquor requires to be cooled to about 300c in order to obtain full colour yield. Therefore when IK dyes are to be used it is preferable to dye by the two-bath process.Typical dyeing recipe- Disperse dye-X%Vat dye-Y%Dispersing agent-0.5-1%Wetting agent-0.5-1%Ph-4-5(attained with 1-2 ml/l of 30% acetic acid)

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Oxidation and soaping- Oxidation and soaping can be be achieved simultaneously using the following recipe:Hydrogen peroxide(35%) 1-2 mlAnionic detergent -.5-1g/lPh-9-10First treat the material for 10-15 min. at 500c with hydrogen peroxide. Then the anionic detergent and raise the temperature to 950c. Soap for 10-15 min.

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Disperse/Vat dyeing system

Method is used when selected vat dyes severely. It stain PET component during high temp dyeing.Vat dye is added at 80c after PET part dyeing rather than adding at the start with disperse dye.Except it the whole process is same as the dyeing in one bath one step.DISPERSE/REACTIVE SYSTEM- Same as one step dyeing except the addition of reactive dye at 80c.This process is used for the reactive dyes which are not stable up to 130c, due to which they can not be used in one step process

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Thermosol Dyeing method-A) continious dyeing. B) pad batch process. Advantages of Thermosol dyeing-Continuous process so it gives higher production.Dye utilization is excellent.Dye can be used afterward.No carrier is required.Fabric is processed in open width form so natural feel of fabric do not get disturbed.No crease formation.Lower energy is required than batch.No extra heat setting is required26

Disperse/vat dye system- PDPS method( continious method)

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ONE BATH ONE STEP THERMOSOL DYEING WITH DISPERSE AND REACTIVE DYES.

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CHEMICAL RECIPE & PROCEDURE.Chemical recipe-Disperse dye-x g/lReactive dye-y g/lSodium bicarbonate or soda ash-5-20g/lUrea-100-200g/lMigration inhibitor-10-20 g/lWetting agent- 1-2g/lPROCESS-pad-dry-thermosol-cool-wash.29

Padding- Padding Temp-20-300 cLiquor pick up-60-80%

ii) DRYING-First partial drying in infrared pre dryer and then fully drying.Partial drying is done to avoid migration of dyes.Drying is done at 120c.

iii) THERMOFIXATIONIt is done at 180-220c, 30-45secIt is the fixation step.iv) PADDING-Padding bath contain NaOH + Na2S2O4V) STEAMING- During this vat dye penetrated inside the cotton part. Then oxidation, soaping and finally washing.30

One bath one step dyeing process-Disperse/Reactive dyes.

Padding in the second step is done using NaCl + NaOH H- brand reactive dye is used.Fixation is done during steaming with saturated steam (102c) for 30-60 sec.Then washing ,soaping and again washing.Recipe-Disperse dye-x g/lReactive dye-yg/lSodium bicarbonate or soda ash-5-20g/lUrea-100-200g/lMigration inhibitor-10-20 g/lWetting agent- 1-2g/l.

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Dye conc(g/l)