Canadian Finishing & Coatings Manufacturing - May/June '24 - 33

PAINT AND COATINGS MANUFACTURING: MIXING & DISPERSION
Maximising Pigment Efficiency
The role of ultra high shear
mixers in premix dispersion
BY ERIN DILLON
n the world of paint and coatings manufacturing,
pigment and solids dispersions play a critical role in
product performance, finish, and longevity. Choosing
the right mixer is not only crucial for optimising
production efficiency but is imperative for product quality.
As regulatory requirements drive the industry towards more
environmentally friendly and sustainable formulations like
waterborne systems, high-solids coatings, and low-VOC
technologies, high-performance processing methods are
becoming the new industry standards.
I
Today's paints, inks, and coatings boast a variety of
innovative formulations and raw materials to produce
a wide array of finishes and value-added functionalities
such as thermochromic, fluorescent, colour-shifting, and
rust-inhibiting properties. However, the success of these
formulations hinge on proper mixing methods. The level of
mixing and dispersion directly impacts key factors of the endproduct
such as colour accuracy, glossiness, conductivity,
stability, adhesion properties, curing rates, weather
resistance, and overall performance. Even conventional
products and established processes can benefit significantly
from a strategic reassessment of the mixing operations. By
embracing modern technologies and refining their approach
to pigment and solids dispersion, manufacturers can achieve
heightened efficiency and enhanced product quality.
Exploring Improved Technologies
The traditional approach to pigment and solids dispersion
involves wetting out powders in a batching tank utilising
a high-speed disperser that turns at tip speeds up to
around 5,000 fpm. The saw-tooth blade of the disperser
produces a deep vortex on the liquid surface into which dry
powder ingredients are added. At this stage, large and loose
agglomerates generally wet-out to create a " pre-mix " that is
then subjected to multiple passes through a dispersion mill.
While effective, this method is plagued by inefficiencies and
high operating costs. Recognising the need for improvement,
manufacturers are exploring alternative techniques to
prepare premixes and disperse agglomerates more efficiently
or even eliminate the milling step altogether.
The ROSS PreMax Ultra-High Shear Mixer is a topentering
batch mixer with Delta ultra-high shear rotor/stator
technology and offers a new solution for premix dispersion.
The Delta rotor is specially contoured for high pumping
capacity and shear intensity. Product is drawn from above
May/June 2024
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Canadian Finishing & Coatings Manufacturing - May/June '24

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