An Efficient Approach to Dispersing Pigments
April 2017 www.coatingsworld.com Coatings World | 45
would the pigment not be utilized for tint
strength, it would also change color when
applied. Sample B and Sample C had the
highest color strength and a ΔE less than
one. These would be the most stable and
most attractive formulations in this case.
For this formulation, overall Sample
B and Sample C had the best performance. More research will be done to optimize these formulations. Additionally,
all dispersion samples will undergo elevated temperature testing for 1 week
at 50°C. Viscosity, particle size, color
acceptance, and color strength will then
again be tested for confirmation of each
additive’s performance.
Conclusion
The results for yellow iron oxide convey
that Sample D was the best dispersant
for that formulation. The higher mo-
lecular structure in combination with
the hyper-branched polymeric chains
was found to be especially useful with
the viscosity of the formulation. This
allows for a higher pigment loading to
be achieved at a fraction of the grind-
ing time. Less machine time, less energy
consumption, and fewer labor costs
drastically reduce the complexity of
processing, simply by utilizing the most
suitable additive. This contributes to
a more cost-efficient way to formulate
pigment concentrates and coatings.
On the other hand, Sample D did not
perform well in the violet-titanium diox-
ide formulation. Most likely, the molecu-
lar weight was too high and the polymeric
side chains were not soluble and caused
incompatibilities with this system. Here,
Sample B and Sample C performed well
in regard to color strength and color ac-
ceptance, and they produced the most
economic grinds by getting the most out
of the pigment. These two additives kept
the violet and titanium dioxide stable
using a “controlled flocculation” matrix
(Figure 12). This allowed for the two pig-
ments to be bound together to prevent
further flocculation by using the disper-
sant as the bridge between the two.
Pigment and additive interactions can
be difficult to determine because there are
so many variables at play. However, the
ability to understand the dispersant and
pigment structure and the forces acting on
them leads to a better understanding of
how to harmonize the two when developing paints and pigment concentrates. CW
References
1. Evonik Corporation, TEGO Chemie
Service GmbH. TEGO Journal, 4th ed.;
2012.
pp 79-89.
2. Mueller,Bodo. Understanding
Additives. European Coatings Literature,
Vincentz
Network GmbH & Co.: Hannover,
Germany 2010
3. Heilen, Wernfried. Additives for
Waterborne Coatings. European
Coatings Literature,
Vincentz Network GmbH & Co.:
Hannover, Germany, 2009.
4. Winkler, Jochen. Dispersing Pigments
and Fillers. European Coatings
Literature, Vincentz Network GmbH &
Co.: Hannover, Germany, 2012.
Figure 12. Controlled flocculation matrix between organic and inorganic pigment.
Figure 11. Color acceptance values for violet-titanium dioxide formulations.
Coatings World is now accepting technical papers
for publication. Email kpianoforte@rodmanmedia.com
on the process for submitting a paper for consideration.
