1. PRESENTATION
ON
DYEING PROBLEMS AND REMEDIES
PRESENTED BY,
FAHMIDA SULTANA; ID#073-23-653
SADDAM HOSSAIN BHUIYAN; ID#073-23-626
DIPAK KUMAR SARKER; ID#073-23-568
S.M.MOHIUDDIN; ID#073-23-657
SABBIR AHMED MAJUMDER; ID#073-23-592

2. Dyeing is the process of adding color to textile products like fibers,
yarns, and fabrics. Dyeing is normally done in a special solution
containing dyes and particular chemical material. After dyeing, dye
molecules have uncut Chemical bond with fiber molecules. The
temperature and time controlling are two key factors in dyeing.
The stages in the processing of textile dyeing:

3. Pretreatment problems : 21%
Dyeing & Printing problems : 23%
Finishing problems : 11%
Biological & machine problems : 24%
Diverse problems : 22%

4. Pretreatment that is known accurate composition. The chemicals are
used for pre-treatment of all fibers and are used for removing dirt, oil,
fatty and waxy impurities. Moreover, these chemicals also act as a mild
stain remover.
70% of the problems due to dyeing can be attributed to the
preparatory pretreatment, because it is the first stage in dyeing
processing. So, dyeing depends on its effectiveness and efficiency.
The dyeing process which follows pretreatment depends on a
number of parameters like:
1. Time
2. Temperature
3. Conc. of chemicals and auxiliaries selection
4. pH of the process etc.

5. Pretreatment problems
Poor absorbency.
Catalytic damage/poor fluidity.
Stains.
Moire effect.
Shade change from selvedge to selvedge.
Shrinkage/distortion.
Creasing/chafe marks.
Handling.
Inferior brightness/luster.
Cloudy dyeing.
Skitteriness.
Pale areas.
Dark spots.
Rope marks.

6. Pretreatment remedies
Use of specialty chemicals.
Select suitable heat setting temperatures.
Thorough relaxation of the material.
Controlled tension and uniformity of batching
during pretreatment.
Checking for rough patches in the machine.
Carry out lab tests.
Carry out preliminary tests with material.
Quality inspection before and after pretretment.

7. Dyeing problems
1. Unlevelness(due to dyeing conditions)
‡ Ending problems
‡ Cloudy dyeing
‡ Pale areas
2. Unlevelness(due to material)
‡ Barriness
3. Unlevelness(due to other reasons)
‡ Skitterness
‡ Listing
‡ Pale areas after dyeing
4. Reproducibility
‡ Deviation of shade
‡ Dyeing too pale
‡ Precipitates in the dye bath
‡ Change of shade
5. Fastness properties
‡ Unexpectedly poor light fastness
‡ Unexpectedly poor wet and rub fastness
6. Spots, marks
‡ Precipitates in the dye bath
‡ Singeing droplets
‡ Change of shade (e.g. blue spots in brilliant red shades)
‡ Dark spots
‡ Specks
‡ Dirt spots

8. Dyeing problems
7. Appearance of the goods
y Dimensional stability (shrinkage)
y Creasing
y Chafe marks
y Stitch distortion (knits)
y Moire effects (on beam)
y Luster
y Handle
y Pilling (staple fibers)
8. Other problems
y Difficulty with heavy shades on fine denier yarn
y Soiling of machine
y Frosting on goods
y Poor running of material in subsequent processing
9. Thermosol dyeing problems
y Listing
y Two-sidedness
y Dark or pale selvedges
y Barry dyeing
y Spots, specks
y Ending
y Pale points of intersection
y Foam formation
y Frosting

9. Major 10 causes of dyeing problem
1. Inadequate pretretment.
2. Wrong dyeing program.
3. Irregular tension.
4. Dye sensitivity.
5. Mechanical affect,Chemical affect & Material affect.
6. Stained adjacent fiber.
7. Migration due to chemicals, wrong dyeing program, drying.
8. Use of volatile carrier, silicon, dispersant.
9. Residue of alkali, boiling agent.
10. Fiber surface, fiber origin & physical change in fiber due to
local pressure, temparature.

10. Major 10 remedies of dyeing problem
1. Optimizing a dyeing process.
2. Select dyes with better dispersion stability, use efficient
dispersants.
3. Adjust the machine more carefully
4. Use special chemicals, antifoamers.
5. Pay attention to perfect pretreatment.
6. Select special dyes (smallll-molecule) .
7. Use silicone-free defoamers & Select suitable carriers, use
overhead heating in the machine.
8. Pay attention to cleanness in the machine
9. Check temperature and air current in drying machine.
10. Avoid migration by using lowest possible pickup and a
suitable migration inhibitor.

11. Fabric defects due to dyeing problems
A.dyeing of cellulosics
Defect Cause Remedies
1.Specky/patchy dyeing Water drop on fabric & too
much foaming.
Avoid water drop & use
defoamer.
2.Dark colored spot Incompatibility & too much
high dyestuff concentration.
Select proper dyestuff& check
the solubility of dyestuff.
3.Dark or light selvedges Non uniform batching . Proper batching.
4.Center of selvedge variation Uneven wearing out of rolls
of padding mangle
&temparature variation.
Unifrom expression from
padding mangle & unifrom
temparature.
5.Face to back variation Migration during
intermediate drying.
Ensure working of all the fan
in dryer.
6.Oxidation patches in vat
dyeing
Improper or premature
oxidation
Take proper care during
oxidation.
7.Bronginess & white marks
in sulphur dyeing
Presence of free sulphur in
the dye bath
Use sodium sulphate.

12. Fabric defects due to dyeing problems
B.dyeing of polyester component of blended fabrics
Defect Causes Remedies
1.Perforetion mark Inadequate leader cloth on to
the beam
Use adequate leader cloth.
2.Moire effect Too high tension during
batching and inadequate heat
setting.
Proper tension during
bathing &poor heat setting of
fabric prior to dyeing.
3.Darker dyed selvedges Improper over lapping. Give proper overlapping.
4.Crush mark in jet dyeing Improper jet diameter. Depending upon fabric
quality.
5.Oily stains Use of wrong type of
defoamer.
Use proper defoamer
particularly when dyeing on
rapid jet dyeing m/c.
6.Poor light fastness Presense of carrier in dyed
fabric
Though removal of carrier.
7.Barre dyeing Basic difference in the
polyester component
particularly when using
textured filament weft.
Take appropriate preventive
measure to avoid mix up of
weft.

13. Yarn defects due to dyeing problems
Yarn defects are-
‡ Strength loss
‡ Harsh handle
‡ Channel building
‡ Unlevel dyeing
‡ Poor batch to batch reproducibility
‡ Package deformation & yarn abrasion
‡ Shade variation in Inner, Middle & Outer layer

14. Yarn defects due to dyeing problems
Remedies for defect in yarn-
1. Package density & size: A uniform package density and size has to be
ensured .
2. Angle of winding: Good winding produces a package of even densities with
good running off properties & minimum of end breakage. Package with cross
winding are preferable.
3. Perforation of spindle: Choking of perforation on spindle hinders smooth
& uniform flow of liquor leading to uneven results.
4. M:L Ratio: A proper MLR has to be maintained during dyeing for
consistency of batches.
5. Pump pressure: The change in pressure after reversal of cycle should not
be significantly high. Necessary action has to be taken for smooth reversal &
prevention of choking of pumps.
6. Entrapped air: Complete air removal has to be ensured prior to pressure
build up for uniform results.
7. pH, Temp. & Time: Optimum values of those parameters have to be
maintained during every stage of processing for best results.

15. 5 tips for remedies of dyeing problem
1. Right first time and all the time right.
2. Maintaining a competative edge is to lay emphasis on
³Quality´.
3. Fullest knowledge on basic facts.
4. Before find a solution of a problem find the cause.
5. Process control,which is one of the most effective
manegerial tool.

16. THANK YOU