storage period. “Their functions vary depending
on rheological profile. For low shear levels, they
prevent settling and expand pot-life. For mid
shear, they improve flow, leveling and applica-
bility, while providing sag resistance. For high
shear levels, they enhance paint performance and
minimize splashing at application.
Thickeners also vary in psedoplasticity. They can be
highly pseudoplastic, effectively contributing to the
KU viscosity construction; intermediates, such as
weak, medium-weak, medium and medium-strong
pseudoplastics, and Newtonian, which provide grea-
ter contribution for construction of the ICI viscosity.
“A KU viscosity value other than the ideal means
tendency for fillers and pigments to settle, short
pot-life, syneresis problems, and emergence of tears
and leveling problems. A non-ideal ICI viscosity value
means low paint yield and trouble applying or trans-
ferring paint to the substrate. The right rheology
agent depends on the application method,” explains
Carvalho.
Sílicas - Formulation benefits
An additive for wide variety of applications, silicas
constantly display improvements in new develop-
ments, especially as regards the evolution in environ-
ment-friendly materials.
Used in the most varied of applications, silicas stand
out in the paint industry for playing important roles
in paint formulation, such as changing rheology, fos-
tering better adhesion to primers, imparting a smooth
touch to the finish and enhancing its washability and
hiding power, opacizing and providing scratch resis-
tance, amongst others.
They are used in all sorts of formulations, including
decorative paints, protective coatings, automotive OEM
and refinish coatings, printing inks, as well as coatings
for furniture and ships. In powder coatings, they act as
flow promoters and stabilizers, extending their shelf-
life. Therefore, even though they represent a small
percentage of paint and coatings formulations, silicas
are responsible for some of their key properties.
Silicas are also used in several applications out of the
paint industry, such as foods, resins, adhesives and
sealants, rubber goods, ceramic flooring, agrochemi-
cals, plastics and animal feeds, to name a few.
Given the wide application spectrum covered by
silicas, there has been a lot of progress in the market
for these products, which also requires constant im-
provement and new developments based on the trend
towards environmentally friendly products.