digital ink formulation to get rid of problem associated with the digital ink manufacturing. dyes and ink of different color and chemical constituents and their affinity with substrate

1. Presentations
@IIT-D
BY
VIVEK YADAV
9457631264

2. Digital ink formulation
Submitted to
Dr. B.S. Butola
Submitted by
Vivek Yadav

3. Basics about Digital inkjet printings

4. INK & IT’S USES

5. BRIEF COMPARISON BETWEEN PRINTPASTE &INKJET INKS

6. • High Purity
• High Solubility
• Optimum rheology properties of solution
•Optimum Particle size and distribution
• Conductivity
• Surface charge and polarity
• Foaming properties
• pH
WHAT WE EXPECT FROM COLORANTS ?

7. Ink Development
Accelerated
shelf life
tests
Drop
analysis
Formulation
development
Dye
purification
Print head
analysis –
Materials
compatibility
Degassing
(cartridges)
High
precision
filtering
Ink mixing –
different
batch
volumes
Purified
powder dye
mixing in
glove box
Raw
materials -
high
precision
weight scale
Dye
synthesis
and
purification
INK PRODUCTION
BASIC OPERATIONS FOR INK FORMULATIONS

8. DYE INK Vs PIGMENTS INK

9. General Pigment Ink
Formulation
( simple and versatile)
o A pigment dispersion
o A polymeric binder
o Water, for aqueous inkjet inks
o Aco-solvent, for wetting and adhesion to
the substrates and jetting properties
(pyrolidone, propane diol, etc)
o Surfactants
o Humectants
o An antifoamagent
o Aviscosity control agent( 20 cps high
molecular weight water soluble polymers )
o Abiocide

10. Pigment color dispersion
 Selectionof pigments based
on thecolor gamut , and light
fastness
 Pigments should be dispersed
 Dispersionstability
 Self dispersing.
 Polymeric dispersantassisted.
Particle size; 0.05 -0.15 micron
Big particles ?
1. Settling
2. Clogging
3. Startup and jetting problem

11. Image quality( small vs big particle size)
Big vs smallparticles
 Big ; higher colour density
 Small ?
 Effective use ofcolour
 Better for glossy substrate
SOLID CONTENT
 10-40 %; higher thebetter (Typical is 20 %)
VISCOSITY AND SURFACE TENSION
 Low viscosity
Low viscosity in pigment dispersion means leaving more room for other ingredients such as
polymeric binders and greater ease in maintaining overall viscosity of the final inks
 Higher surfacetension
High S.T can be controlled by surfactant but low S.T cant be balanced well

12. Other essential
ingredientsBINDERS
 Incorporating polymeric binder in general
difficult; these are film forming substances.
 Low T.g ?
To keep ink soft and prevent clogging at relatively low
temperature
 Reliable jetting(To maintain the low viscosity and formulation
space for jetting reliability)
 Random or blockco-polymers
 Wateras the carrier ; 50-80%
 Co-solvent( rheology modifiers) ,
Propanediols (1,2;1,3, 2,2), 2-
pyrrolidone,PEG, PPG, glycerol,etc.
Surfactants
 High HLB for colloidalstability
 Low HLB for low surfacetension
 ink can wet the nozzle capillary
 Maintain the meniscus at the nozzletip
 reliable jetting
 Short-chain ethylene glycol based nonionic surfactants

13. Typical ink Formulation
• 3-6% dye
• 70-80% water
• 20-25% Humectant(DEG/2-Pyrrolidone)
• Surfactant (perflouro based)
• Penetrating agent (Hexane-1,6 diol)
• Preservative (methyl-isothiazolones)
• Corrosion Inhibitors (Benzothiazoles)
• Electrically conducting Lithium salts
Viscosity ~1-3 centipoise
Surface Tension ~ 35 dynes per cm

14. Pigment inks; pros & cons

15. Types of pigment inks and their process route

16. Disperse ink
Expectations
 Dye should have good dispersibility (physio-chemical property)
 Reduction clearingability
 Of course good all round fastness

17. Desperse Ink preparation
 Removalof saltsand otherorganic impurities
 High pressure milling for good dispersion
and controlling particlesize
 Purification
 Ultracentrifugation
 Ultrafiltration
 Reverseosmosis
Desperse dye formulation
 Aqueousdispersions
 Solids ~ 20%
 Particle size ~ 0.1-0.25micron
 Viscosity ~ 10-50 mPa.s

18. Selection of dispersing agents

19. Disperse ink Process flow
Specific
Pretreatment
 Sodium alginate = 100-200 gm/kg
 Citricacid = 0-2 gm/kg
 Pad and dry
Fixation
 Could be
Thermosol process
HT steam ~ 1800 C
Washing
 Cold wash
• Soap neutral (1-2 gpl) ~ 400 C
• Reductionclearing ~ 800 C
1-2 gpl sodium hydrosulphite
2 gpl NaOH
1 gplsurfactant
• Hot water wash ~400
• Cold wash
• Dry

20. Disperse direct pros & cons

21. Disperse sublimation ; pros & cons

22. Reactive Dye Ink
Substrate ; cotton viscose silk;
Ink chemistry;
• MCT
• Vinyl sulphone
• Di- chloro trizine dyes ?
Factors affecting stability of ink
Ionic nature;
i. Amine and hydroxyl group moiety can react with reactive
dye.
ii. water-soluble organic solvents may possibly react with
reactive dyes.
Hydrolysis
I. The role of sodium carbonate is as a catalyst to promote
hydrolysis by increasing pH.

23. Water based
inks……START
UP PROBLEM ?
Near nozzleevaporationof watermeans increased solidsat the
surface creating an obstruction flow and thus formationof drop
and dropsize, leading tostart up failure, and poor imagequality
SOLUTION …….rheology modifiers …?
 Lessvolatileorganicsolvents inoptimum concentration are
added, this reduces rateof evaporation, such as, EG, DEG, 2-
butanol, urea, etc.

24. Pretreatment for inks formulation
beyond conventional pre-treatment

26. Specific pretreatment along with Post treatments- REACTIVE DYES

27. WHAT IF NOT PRETREATMENT AND AFTER PRETREATMENT

28. POST TREATMENTS FOR DIFFERENT INKS

29. Some commercial digital inks

30. References
1. Yoshiki Akatani technical brochure, Fixing of Dye on Various Textile and Inkjet
Printing, Nippon Kayaku Co. (2005).
2. Nagase Sangyo Co., in the text Textile Printing Seminar (1999).
3. Akira Asai et al., `Impact of an ink drop on paper', IS&T NIP7 Proceedings
(1991).
4. Burkinshaw, D.K., Dyes and Pigments, 33, 11, 1887.
5. Piriya Putthimai et al., `Comparison of textile print quality between inkjet and
screen printing', Surface Coating International Part B, B1, 88, 1-82, March 2005.
6. Yasuhiko Kawashima et al., `The development of new disperse dye inks for inkjet
textile printing', IS&T NIP19 Proceedings (2003).