INNOVATIONS: PRESENT&FUTURE
Who Helps Marine Primers Sail Ahead of the Rest? We Do! Dr. Robert Gibbison Ashland Global Holdings Inc. - Covington, United States
rgibbison@ashland.com
Z
inc-rich primers are used to protect steel surfaces from corrosion.
With a long history of supplying multiple types of water-soluble polymers
Unlike typical paints and epoxide coatings which resist corrosion
for inorganic zinc- rich primers, Ashland’s Klucel™ hydroxypropyl cellulose
primarily by forming an impermeable barrier between the metal and
is widely used by marine and heavy-duty paint producers across the
corrosive atmospheric elements (e.g. water, oxygen), zinc-rich primers
globe. Our technicians and solvers have striven to help customers to
provide corrosion protection principally through cathodic galvanic
reduce process costs, by developing an HPC with a quicker dissolution
protection where the primer functions as a sacrificial layer preferentially
time, compared to conventional HPC’s. Furthermore, this innovative
oxidizing rather than the steel substrate.
approach has led to increased thickening efficiency which in turn
Of the two major types of zinc primers, inorganic and organic, inorganic
contributes to a reduced dosage.
zinc primers typically use a silicate binder to promote zinc adhesion to the Ashland has launched a new grade of cellulosic ether as a thickener and
such as epoxy resins.
anti-sagging agent for inorganic zinc-rich primers. It is suitable for use
Inorganic zinc-rich primers contain higher zinc levels (>65%) versus
in permanent as well as temporary ‘shop’ primers. This brand new HPC
organic zinc primers. The combination of higher zinc levels and reactive
technology (commercial name: Klucel™ MS hydroxypropyl cellulose)
silicate binder typically provides superior corrosion resistance compared
has enabled a major improvement to be made in dissolution speed in
to their organic counterparts with longer coating system life expectancy.
polar organic solvents including methanol, isopropyl alcohol (IPA) and
Surface preparation is critical to ensure good application and long-term
IPA / Xylene blend. Furthermore, the thickening efficiency is significantly
corrosion resistance.
improved when compared to conventional HPC’s.
10500 10000 9500 9000 8500 8000 7500 7000 6500 6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0
© Ashland
torque, µNm
surface of the base material, whereas organic zinc primers use binders
new Klucel™ MS
conven�onal Klucel™ M
0
10
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30
�me, minutes
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Figure 1: Klucel™ MS HPC for rapid viscosity build-up in polar organic solvents.
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N. 29 - 2019 APRIL - ipcm® Protective Coatings
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