Pigment dispersions preparations and printing on Textiles

1. 04th Februray
2010
Dr Sanjiv Kamat
Pigment PrintingPigment Printing
OfOf
TextilesTextiles
Dr. Sanjiv Kamat
Pidilite Industries Limited

2. 04th Februray
2010
Dr Sanjiv Kamat

3. 04th Februray
2010
Dr Sanjiv Kamat

4. 04th Februray
2010
Dr Sanjiv Kamat

5. 04th Februray
2010
Dr Sanjiv Kamat
Pigment Dispersions –Pigment Dispersions –
Historical DevelopmentsHistorical Developments
 As old as 3000 years with mineral pigments and naturalAs old as 3000 years with mineral pigments and natural
polymers as binder and thickeners(starch,glue)polymers as binder and thickeners(starch,glue)
 1920’s- Organic Pigment dispersions1920’s- Organic Pigment dispersions
 1930’s –Emulsion copolymerisation techniques.1930’s –Emulsion copolymerisation techniques.
 1937 –Pigment paste based on water in oil emulsion1937 –Pigment paste based on water in oil emulsion
 1950 – Oil in water systems.1950 – Oil in water systems.
 1960- Aqueous self crosslinking dispersions as binders1960- Aqueous self crosslinking dispersions as binders
 Early 60’s - Pidilite introduced pigmentEarly 60’s - Pidilite introduced pigment
dispersion in India.dispersion in India.
 1990s Ecological improvements(emmission)1990s Ecological improvements(emmission)
 Digital printingDigital printing

6. 04th Februray
2010
Dr Sanjiv Kamat
Why Pigment Printing ?Why Pigment Printing ?
 Versatile-Suitable for all substrates andVersatile-Suitable for all substrates and
machinesmachines
 Low impact on waste waterLow impact on waste water
 Low consumption of water, no washingLow consumption of water, no washing
after printingafter printing
 Short process cycle –faster output , Print,Short process cycle –faster output , Print,
dry,fixdry,fix
 Best light fastnessBest light fastness
 Very High ReliabilityVery High Reliability
 Zero printing defects possibleZero printing defects possible

7. 04th Februray
2010
Dr Sanjiv Kamat
Relative properties of PrintingRelative properties of Printing
stylesstyles
PropertiesProperties PigmentPigment SubstantiveSubstantive
LightLight
WashingWashing
RubbingRubbing
WeatheringWeathering
HandleHandle
ExcellentExcellent
AcceptableAcceptable
GoodGood
Very GoodVery Good
AcceptableAcceptable
GoodGood
Very GoodVery Good
Very GoodVery Good
PoorPoor
ExcellentExcellent

8. 04th Februray
2010
Dr Sanjiv Kamat
• Colour pigment
• Binding agent
• Fixer
• Thickener
• Auxiliaries
- emulsifiers
- softeners
Components of Pigment Printing System

9. 04th Februray
2010
Dr Sanjiv Kamat
• Pigment (25-45 %)
• Water
• Auxiliaries
- emulsifiers / dispersing agents
- Co solvent / glycols (few)
- preservative
Composition of the Pigment Dispersion

10. 04th Februray
2010
Dr Sanjiv Kamat
Factors influencing Selection of PigmentFactors influencing Selection of Pigment
Fastness toFastness to
WashingWashing
LightLight
SolventSolvent
PerspirationPerspiration
ChlorineChlorine
HeatHeat
SalivaSaliva
LegislationsLegislations

11. 04th Februray
2010
Dr Sanjiv Kamat
Influence of Particle Size of PigmentInfluence of Particle Size of Pigment
 FlocculationFlocculation
 Hue/Tint StrengthHue/Tint Strength
 Hiding/TransparencyHiding/Transparency
 Gloss/Flatting and Film appearanceGloss/Flatting and Film appearance
 ViscosityViscosity
 StabilityStability
 Weather ResistanceWeather Resistance

12. 04th Februray
2010
Dr Sanjiv Kamat
PigmentsPigments
Primary Particles
0.01-5mu
Aggregates
0.05-50mu
Agglomerate
0.1-1000mu

13. 04th Februray
2010
Dr Sanjiv Kamat
Pigment dispersionPigment dispersion
 Large number ofLarge number of aggregatesaggregates andand agglomeratesagglomerates
formed during drying and pulverizing process offormed during drying and pulverizing process of
pigment press cakepigment press cake
 To obtain betterTo obtain better gloss, rheological propertiesgloss, rheological properties
and color strengthand color strength pigment applications needpigment applications need
pigment in disperse formpigment in disperse form
 Size of aggregates and agglomerates is reducedSize of aggregates and agglomerates is reduced
fromfrom 10-60 micron10-60 micron to belowto below 1 micron1 micron

14. 04th Februray
2010
Dr Sanjiv Kamat
Dispersion ProcessDispersion Process
 Size Reduction:Size Reduction: Breaking of larger aggregatesBreaking of larger aggregates
and agglomerates into smaller primary particlesand agglomerates into smaller primary particles
by impact and shear forceby impact and shear force
 Wetting Process:Wetting Process: Uniform spreading of liquidUniform spreading of liquid
medium on the pigment surface making amedium on the pigment surface making a
contact angle of zero degree. Proper wettingcontact angle of zero degree. Proper wetting
improves glossimproves gloss
 Stabilization:Stabilization: Dispersed particles areDispersed particles are
prevented to come togetherprevented to come together

15. 04th Februray
2010
Dr Sanjiv Kamat
Dispersion Properties Depend uponDispersion Properties Depend upon
 Suitability of pigmentSuitability of pigment
 Particle sizeParticle size
 Particle size distributionParticle size distribution
 Degree of dispersionDegree of dispersion
 Electrical chargeElectrical charge
 Specific gravitySpecific gravity
 Crystal structure & stabilityCrystal structure & stability

16. 04th Februray
2010
Dr Sanjiv Kamat
TextureTexture
 Feel and appearance of surface especially howFeel and appearance of surface especially how
rough or smooth it is .rough or smooth it is .
 Decided by theDecided by the degree of aggregationdegree of aggregation of theof the
primary particlesprimary particles
 Soft textureSoft texture havehave large agglomerateslarge agglomerates and fewand few
aggregatesaggregates
 Large number of aggregatesLarge number of aggregates givegive hard texturehard texture
 Various surface treatments used to improveVarious surface treatments used to improve
texturetexture

17. 04th Februray
2010
Dr Sanjiv Kamat
Texture is affected byTexture is affected by
 pH(fluctuation in the process)pH(fluctuation in the process)
 TemperatureTemperature
 Solvent in condensationSolvent in condensation
 Process slow or fast(Rate of addition)Process slow or fast(Rate of addition)
 Drying process(Convection,IR,Air suction)Drying process(Convection,IR,Air suction)

18. 04th Februray
2010
Dr Sanjiv Kamat
Texture and structureTexture and structure
SOFTSOFT
<<Bisazo < Phthalocyanine <Bisazo < Phthalocyanine <
monoazo < betanaphthol <monoazo < betanaphthol <
Benzimidazolone < QuinacridonesBenzimidazolone < Quinacridones
< DPP < Perylene < Carbazole< DPP < Perylene < Carbazole <<
HARDHARD

19. 04th Februray
2010
Dr Sanjiv Kamat
Dispersing EquipmentDispersing Equipment

20. 04th Februray
2010
Dr Sanjiv Kamat
Size ReductionSize Reduction
 Commonly used EquipmentsCommonly used Equipments
Type Of Action
Ball Mill Impact
Sand Mill Sheer+Impact
Impact+Sheer
Bead Mill Sheer+Impact
Three Roller MillSheer
Kneader Sheer
Extruder Sheer
Equiptment
Attritors

21. 04th Februray
2010
Dr Sanjiv Kamat
Influence of pigment dispersion particle sizeInfluence of pigment dispersion particle size
on printingon printing
 Small particle size may cause a low colour yield besides clogging ofSmall particle size may cause a low colour yield besides clogging of
screens and may also entail thixotropic propensity of print pastes.screens and may also entail thixotropic propensity of print pastes.
Wash fastness may be inferior since the pigment particles may notWash fastness may be inferior since the pigment particles may not
be held properly in the layer of binder film.be held properly in the layer of binder film.
 For instance, 40g/kg shade using a pigment dispersion having aFor instance, 40g/kg shade using a pigment dispersion having a
particle size of 0.1 micron and binder of 0.3 micron, since theseparticle size of 0.1 micron and binder of 0.3 micron, since these
particles are not held appropriately in the binder film, the washparticles are not held appropriately in the binder film, the wash
fastness may be affected. , since with very fine particle size; thefastness may be affected. , since with very fine particle size; the
pigments are liable to bleed on washing e.g. Pigment Red 2 with apigments are liable to bleed on washing e.g. Pigment Red 2 with a
lower particle size. Red and Bordeaux pigments have a tendency tolower particle size. Red and Bordeaux pigments have a tendency to
bleed on washing .bleed on washing .
 Large particle size may entail dull prints.Large particle size may entail dull prints.
 High viscosity of pigment dispersions may not only lead to thickerHigh viscosity of pigment dispersions may not only lead to thicker
print pastes but also cause inadequate penetration during printingprint pastes but also cause inadequate penetration during printing
on the substrate.on the substrate.

22. 04th Februray
2010
Dr Sanjiv Kamat
Recent Development in Emulsifiers
No clear technical trend visible
- combination products
- emulsifier/rheolog. additive
- emulsifier/rheolog. additive/fixing agent
- pure emulsifier
• APEO-free
• Non-ionic

23. 04th Februray
2010
Dr Sanjiv Kamat
Pigment Printing BindersPigment Printing Binders shouldshould
 Have good adhesion but no tackHave good adhesion but no tack
 Be resistant to chemical and mechanicalBe resistant to chemical and mechanical
stressstress
 Be flexibleBe flexible
 Be non yellowingBe non yellowing
 Be removable from screensBe removable from screens
 Be shear stableBe shear stable
 Resistance to agingResistance to aging

24. 04th Februray
2010
Dr Sanjiv Kamat
Binder Properties Influenced byBinder Properties Influenced by
N
E
G
A
T
I
V
E
P
O
S
I
T
I
V
E
AN
NBA
Soft Tacky
Softer More Tacky
Softest Most Tacky
Hardest
Harder
Hard
Lowest
Fastness
Best
Fastness
NBA
EA
B
Styrene
MA

25. 04th Februray
2010
Dr Sanjiv Kamat
BindersBinders
MonomerMonomer Tg (°C)Tg (°C)
EthyleneEthylene -125-125
ButadieneButadiene -78-78
Butyl AcrylateButyl Acrylate -52-52
Ethyl AcrylateEthyl Acrylate -22-22
Vinyl AcetateVinyl Acetate +30+30
Vinyl ChlorideVinyl Chloride +80+80
Methyl MethacrylateMethyl Methacrylate +105+105
Styrene/AcrylonitrileStyrene/Acrylonitrile +105/130+105/130

26. 04th Februray
2010
Dr Sanjiv Kamat
1. not self-cross linking
2. self-cross linking (reactive side groups)
Parameters influencing crosslinking
• Type and number of reactive groups
• Temperature
• Duration
• pH value
Crosslinking results in improved
1. Fastnesses
2. Stability to temperature
3. Permanency of effects
Type of Binders

27. 04th Februray
2010
Dr Sanjiv Kamat
Binders Functional GroupsBinders Functional Groups
 Carboxyl functionality –Binders contain acrylicCarboxyl functionality –Binders contain acrylic
acid or methacrylic acid as co-polymers.acid or methacrylic acid as co-polymers.
Provides sites for cross-linking reactionsProvides sites for cross-linking reactions
 Amide Functionality – Acrylamide as a part ofAmide Functionality – Acrylamide as a part of
the functional group .Binders havingthe functional group .Binders having
substituted acrylamide groups have self crosssubstituted acrylamide groups have self cross
linking propertieslinking properties
 SBR Binders-Butadiene monomer providesSBR Binders-Butadiene monomer provides
elasticity ,while styrene and acrylonitrile giveelasticity ,while styrene and acrylonitrile give
oil and solvent resistance Disadvantages areoil and solvent resistance Disadvantages are
oxidation and discoloration due to residualoxidation and discoloration due to residual
double bondsdouble bonds

28. 04th Februray
2010
Dr Sanjiv Kamat
Binder Particle SizeBinder Particle Size
 Smaller the particle size of the binderSmaller the particle size of the binder
results in brighter prints as totalresults in brighter prints as total
internal reflection increases.internal reflection increases.
 Bigger particle size binder may increaseBigger particle size binder may increase
coverage but prints may look dullercoverage but prints may look duller
 Very small particle size will lead ofVery small particle size will lead of
clogging of screens because ofclogging of screens because of
agglomerationagglomeration

29. 04th Februray
2010
Dr Sanjiv Kamat
Recent Development in Binders
• Increasingly softer handle
• Fastnesses improved
• Running properties were improved
• Reduction in residual free monomer content

30. 04th Februray
2010
Dr Sanjiv Kamat
Normal
CH2=CH-CO-NH-CH2-OH N - methylol acrylamide
detaching formaldehyde
reaction partners: - sec. amino groups
- N-methylol groups / N-methylol ether groups
- amide groups
- melamine groups
- dicyan diamide groups
- related groups
Alternative
CH2 - CH- epoxy components (e.g. epichlorhydrin
O formaldehyde-free
reaction partners: - hydroxylic / carboxylic groups
- amino groups, react. methylene groups
Binders Components for self cross
linking

31. 04th Februray
2010
Dr Sanjiv Kamat
••
Synthetic Thickeners
-CH2 -CH - CH2 - CH CH2 -CH - CH2 - CH -
COOH COOH
COO - COO - n
first synth. thickeners in 1969
• mechanism:
n - addition of alkali (NH4OH) causes an electrostatic repellency
- formation of a three-dimensional network = increase in viscosity
• molecular weights in the range of 1000000
• partially crosslinked
n
OH-

32. 04th Februray
2010
Dr Sanjiv Kamat
Thickener propertiesThickener properties
MolecularMolecular
WeightWeight
High / LowHigh / Low ViscosityViscosity High/LowHigh/Low
PolymerPolymer
ContentContent
High /LowHigh /Low ViscosityViscosity High/LowHigh/Low
SameSame
PolymerPolymer
contentcontent
HighHigh
MolecularMolecular
WeightWeight
LowLow
MolecularMolecular
WeightWeight
Low DosageLow Dosage
Low CoverageLow Coverage
Low FastnessLow Fastness
High DosageHigh Dosage
HighHigh
CoverageCoverage
High FastnessHigh Fastness

33. 04th Februray
2010
Dr Sanjiv Kamat
Pidicryl SHRP - RheologyPidicryl SHRP - Rheology
modifiermodifier
0
20
40
60
80
100
AQA +SHRP
Time
Sec
Viscosity
Rheology change under Shear ( Squeegee Pressure)
Shear force
Shear force released

34. 04th Februray
2010
Dr Sanjiv Kamat
Rheology Modifier - Pidicryl SHRPRheology Modifier - Pidicryl SHRP
 Reduces Flushing tendency on differentReduces Flushing tendency on different
fabricsfabrics
 Improves colour yieldImproves colour yield
 Improves brightnessImproves brightness
 Improves leveling highly recommendedImproves leveling highly recommended
in full blotch printingin full blotch printing
 Lower penetrationLower penetration
 Higher coverage Mts/Kg of print pasteHigher coverage Mts/Kg of print paste
 Best results at pH > 8Best results at pH > 8

35. 04th Februray
2010
Dr Sanjiv Kamat

36. 04th Februray
2010
Dr Sanjiv Kamat
Two trends:
a) higher efficiency / price optimization
b) improved technology / multifunctional
• pasty
• lower hydrocarbon content
• non-fuming
• high purity / good and quick swelling behaviour
• good storage stability / little settling
Recent Development in Thickeners

37. 04th Februray
2010
Dr Sanjiv Kamat
Two trends:
a) higher efficiency / price optimization
b) improved technology / multifunctional
• pasty
• lower hydrocarbon content
• non-fuming
• high purity / good and quick swelling behaviour
• good storage stability / little settling
Recent Development in Thickeners

38. 04th Februray
2010
Dr Sanjiv Kamat
38
Developments in Fixing AgentsDevelopments in Fixing Agents
• Melamine resin fixing agent / contains HCHO
higher etherification, thus:
- reduced HCHO content
- less HCHO emission during drying and fixation
- reduced HCHO content on the fabric
- less reactivity
• Isocyanate fixing agent / HCHO-free
-cold fixing / not blocked / shelf life /
high reactivity
- hot fixing / blocked

39. 04th Februray
2010
Dr Sanjiv Kamat
Ecological IssuesEcological Issues
Air
• hydrocarbons (white spirit/thickener/antifoam)
• HCHO (fixing agent/binders/preservative)
• monomers (binding agent/fixing agent/thickener)
• fume (thickener/softener/urea/glycols)
Water
• hydrocarbons (white spirit/thickener/softener/antifoam)
• heavy metals (Pigments)
• APEO (emulsifiers/binders/softener)
Fabric
• HCHO (fixing agent/binders/preservative)
• fastnesses (binding agent/fixing agent/pigments)
• MAK amines (colour pigments (some in the red range))
• APEO (colour pigments,binders),

40. 04th Februray
2010
Dr Sanjiv Kamat
Influencing Factors – Pigment PrintingInfluencing Factors – Pigment Printing
 Viscosity: Design, machineViscosity: Design, machine
 Water HardnessWater Hardness
 Screen MeshScreen Mesh
 Drying TemperatureDrying Temperature
 Fabric typeFabric type
 pH of printing pastepH of printing paste
 Particle size of Pigment dispersion and BinderParticle size of Pigment dispersion and Binder

41. 04th Februray
2010
Dr Sanjiv Kamat
Fastness not achieved !Fastness not achieved !
LightLight Depth of ShadeDepth of Shade
PerchPerch Pigment selectionPigment selection
High TempHigh Temp Pigment SelectionPigment Selection
CrockingCrocking Depth of ShadeDepth of Shade
Binder TypeBinder Type
Binder ConcentrationBinder Concentration
Curing conditionsCuring conditions
Fabric Type and GeometryFabric Type and Geometry

42. 04th Februray
2010
Dr Sanjiv Kamat
Colour Textile interactions in Ink Jet PrintingColour Textile interactions in Ink Jet Printing
Print Head Technologies
Performance
Drop performance
Ink/Material compatibility
Nozzle clogging
Nozzle crusting
Biological growth
Contamination
Long-term operability
Textile/Ink Interaction
Drying time Colour value/yield
Chroma (colour quality) Spreading/wicking
Rub fastness Water fastness Light fastness
Colour /Ink Formulation
Property
Surface tension Viscosity
Specific gravity pH
Conductivity Dye purity
Dye purity/solubility
Toxicological properties
Particle size Stability
Accoustic properties Shelf life
Textile

43. 04th Februray
2010
Dr Sanjiv Kamat
Printhead TechnologyPrinthead Technology
•Thermal Drop on Demand(DOD)
•Piezo Drop on Demand
•Binary Continuous inkjet heads
•Multi-deflection continuous heads
•Air jet deflection
• Valve Jet

44. 04th Februray
2010
Dr Sanjiv Kamat

45. 04th Februray
2010
Dr Sanjiv Kamat
March 2007
GAP Delhi
Dr Sanjiv Kamat 45
Thank you