Functions of Dispersing Additives in Ink: By: Adesh Katariya Manager-R&D, Tirupati Inks LTD
Functions of Dispersing Additives in Ink: By: Adesh Katariya Manager-R&D, Tirupati Inks LTD
Functions of Dispersing Additives in Ink: By: Adesh Katariya Manager-R&D, Tirupati Inks LTD
Additives in Ink
By :
Adesh Katariya
Manager- R&D, Tirupati Inks Ltd
plast.adesh@gmail.com
Pigment
A pigment is a coloring particle which is insoluble in the
application media.
Particle size and crystal structure of pigments determine
the application properties like gloss, tinting strength etc
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Pigment Properties
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Pigments in Comparison
Organic Inorganic
Property
Pigment Pigment
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Pigment Dispersion
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Improved Dispersion and Dispersing Additive
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De-flocculation -Flocculation
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Wetting and Dispersing Process
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Pigment wetting:
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Proper Wetting
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Wetting and Surface tension
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Stabilization of pigment suspension :
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Pigment Stabilization
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Pigment Stabilization Mechanism
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WHY Dispersant Required ?
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Dispersing Agent and Rheology
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Dispersants families
In term of chemical structure one can divide dispersing
agents into the two following classes:
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Electrostatic stabilization
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Sterical stabilization
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Mechanism of Steric Stabilization
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Mechanism of Steric Stabilization
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Mechanism of Steric Stabilization
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Mechanism of Steric Stabilization
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Mechanism of Steric Stabilization
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Polymeric dispersants
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Structure of Wetting and Dispersing
Additives
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Pigment affinic groups
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Dispersing Additives :Advantages
Higher gloss
Lower haze
Higher color strength
Improved hiding power
Better transparency
Low viscosity / Newtonian Flow
No flooding & floating
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Co-polymer/functional polymer
configurations
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Dispersing Additives : How to stabilize
the pigments
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Dispersing Additives : How to stabilize
the pigments
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Adsorption/Anchoring of Dispersing agent
on Pigment Surface
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Anchoring Mechanisms
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Anchoring Through Ionic or Acidic/Basic
Groups
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Anchoring Through Hydrogen-Bonding
Groups
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Anchoring Through Polarizing Groups
It is possible to anchor a
polymeric dispersant onto a
pigment particle surface
simply via van der Waals
interactions and without
recourse to ionic, hydrogen-
bonding, or polarizing effects.
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TiO2: Surface Treatments
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TiO2: Surface Treatments
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Groups on Carbon black Surfaces
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Interaction W/D Additives with other
Pigments
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Wetting and Dispersing Additives: Class
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Low molecular weight dispersants
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Oligomeric dispersants
Based upon fatty acid
chemistry, having polar
heads based on tertiary
amines.
Typically, these
molecules are oligo-
functional, meaning that
more than two amino
anchoring groups are
present.
The molecular weight
ranges from 1,000 to
3,000 g/mol.
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High molecular wt dispersants
High molecular weight dispersing agents can be linear or branched
molecules with molecular weights between 5,000 and 20,000
g/mol.
Excellent stabilization, due to a high number of anchoring groups
along the polymer backbone which bind to numerous sites on the
pigment surface.
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Polyurethanes
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Star-shaped dispersing polymers
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Block copolymers Dispersant
Based on Controlled free Radical Polymerization (CFRP) technology
, enables the precise design of polymer structures.
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CFRP Technology based Dispersant's
structure
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Polyacrylates
Polyacrylic dispersing agents have linear structures with a
C-C backbone that bears various functional side groups
and short side chains.
The main difference to polyurethane-based dispersants is
their higher molecular weight.
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Co-polymer dispersants :
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Comparison in Poly Acrylic and
Polycorboxylic co-polymer base D.A.
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Surfactants
Surfactant molecules are able to modify the
properties and, in particular, they lower the
interfacial tension between the pigment and
the resin solution.
This surface activity arises because the
surfactants' structure consists of two groups
of contrasting solubility or polarity.
In aqueous systems, the polar group is
known as a hydrophilic group and the non-
polar group as hydrophobic or lipophilic.
In non-aqueous systems, the polar group is
known as the oleophobic group and the non-
polar group as oleophilic.
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Surfactants
Surfactants are classified according to their chemical structure and, more
specifically, their polar group: anionic, cationic, electroneutral and non-ionic .
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Surfactants : Points
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Fatty Acid Derivatives
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Phosphate Esters
• .
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Polyacrylic acid/ Sodium polyacrylate
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Acetylene Diols
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