This past year brought a slew of innovations in the powder coating industry. In this Buyers Guide edition of Powder Coated Tough, we take a glimpse at recently commercialized advances and emerging technology in the powder coatings industry, specifically within the following segments: powder coating technology, powder formulation (raw materials and pigmentation), and instrumentation.
Powder Coating Technology
Corrosion resistance was a big topic this past year. Axalta
Coating Systems introduced two new high-temperature, corrosion-resistant
internal pipe coatings to its Nap-Gard® functional
coatings collection. The new Nap-Gard 7-0017HT and 7-0017VHT
Black Beauty FBE products are thermosetting epoxy powders
designed to provide excellent chemical resistance when operating
in temperatures up to 392°F (200°C). Corrosion caused by
carbon dioxide (CO2) and hydrogen sulfide (H2S), often found in
sour crude oil, is a major challenge for the oil and gas industry.
Axalta’s introduction of these high glass transition (Tg) temperature
internal pipe coatings are designed to combat this problem.
When properly applied with Nap-Gard 7-1808 primer, Nap-Gard
7-0017HT and 7-0017VHT exhibit extreme corrosion protection
against high levels of H2S and CO2, as well as methane (CH4) even
at high temperatures and pressures.
Evonik debuted coatings for extreme environments based on
innovative polyether ether ketone (PEEK) powders VESTAKEEP®.
These coatings reduce the wear and tear of components in
demanding industrial applications. The PEEK powders of Evonik’s
VESTAKEEP brand are particularly suitable for applications
that are subjected to extreme requirements, like mechanical,
thermal and chemical exposure. The coating material is able to
withstand permanent operating temperatures of up to 482°F
(250°C) and is characterized by its unique ability to resist abrasion
Due to the excellent tribological performance of coatings made
from these specially developed powders, the friction between
sliding surfaces is significantly reduced, which in turn increases
efficiency and economy of operation—for example: lower fuel
consumption and lower CO2 emissions in combustion engines,
extended service life of bearings, or higher turbine speeds.
These coatings also allow for employing more cost-efficient
substrate materials for components used in applications with
sliding friction. The various VESTAKEEP PEEK powders are
composed of particles with average particle sizes ranging from 5 to
110 µm. They can be applied by flame and electrostatic spraying
methods, or as aqueous dispersions. With electrostatic application,
layer thicknesses can range from 20 to 300 µm.
New coating technology for alternate substrates such as
medium density fiberboard (MDF) and natural wood was
introduced in 2017. IGP announced that
its IGP-RAPID powder coatings are based
on new raw materials combined with
IGP technology, enabling a revolution in
low-temperature powder coatings. The
range of baking temperatures from 266°F
(130°C) and curing times of 3 minutes
are a breakthrough compared to existing
powders on the market. IGP explains
that the coater benefits in several ways—
from an ecological coating, low curing
temperatures, and from powder coatings
that enhance product design and
provide long-term functional protection.
The seamless all-around coating enables
coverage of edges and areas in one work
step. Three-dimensional (3D) geometries
display a homogenous, aesthetic surface.
DVUV introduced its UVMax® line
of opaque semi-smooth finishes for MDF
claiming it provides a one-of-a-kind
finish on components. Powder-coated
MDF allows design freedom and durability, all with zero volatile
organic compounds (VOCs), the company adds. Ideal markets for
powder-coated components include retail store fixtures, healthcare,
education and office furniture.
Major advances in architectural coatings were delivered by fluoropolymer
companies in 2017. Arkema announced the addition of
new Kynar polyvinylidene difluoride (PVDF) powder coatings that
offer extreme resistance to chemicals, ultraviolet (UV) exposure,
acids and bases. Included in the new powder product line are Kynar
Flex 2850 PC and Kynar ADX Flex 281, targeting applications that
require varying levels of flexibility, adhesion and differing application
methods. Both spray and dip coating options are available as
well as primerless options using Arkema’s patented Kynar ADX technology.
Kynar Flex 2850PC can be spray applied in thicker layers
than most fluoropolymers, making it a “process friendly” powder
coating. The new Kynar PVDF powder coatings are designed for
the protection of small metal chemical storage tanks, high purity
manufacturing components, valves, pumps, ducts, and other chemical
handling or mining equipment subjected to acids, halogenated
chemicals, petrochemicals, continued abrasion and continuous
exposure temperatures of up to 203°F (95°C). Kynar Flex 2850 PC
powder coatings may be safely used on parts intended for repeated
contact with food per Title 21, Code of Federal Regulations, Chapter
1, part 177.2600, and is USP Class 6 compliant for applications in
the biotech industry.
AGC Chemicals presented interesting findings with fluoroethylene
vinyl ether (FEVE)-based powder coatings. Coatings based
on this copolymer offer excellent UV durability, typically enduring
20 or more years in a South Florida environment without exhibiting
significant chalking or coating degradation. The fluoroethylene
monomer in the resin backbone protects the vinyl ether
groups from degradation, whereas the vinyl ether moieties allow
the polymer to be functionalized. In this case, it provides a site to
attach a hydroxyl group, which can be crosslinked with diisocyanate
curing agents. Powder coatings based on AGC’s FEVE resins
cured with blocked aliphatic isocyanates have withstood more
than 10 years exposure in both Okinawa and South Florida with
greater than 50 percent gloss retention. The same formulations
pass 10,000 hours exposure to QUV-B (ASTM D4587) and 3,000
MJ/m2 EMMAQUA accelerated testing (ASTM D4364).
Additionally, superdurable polyester resin can be blended
with FEVE polymer to provide advantages in metallic-containing
formulations. Their studies show that the polyester component
stratifies below the fluoropolymer, leaving the metallic at
the interface between the FEVE and
polyester. This phenomenon protects
aluminum flake from degradation from
hydrolysis commonly seen with exposure
to outdoor environments. AGC
presented energy dispersive x-ray spectroscopy
(EDX) cross sectional analysis
to verify this stratification. Not only does
this formulation system exhibit exceptional
UV durability, but also excellent
corrosion resistance as evidenced by
AGC’s 4,000-hours salt fog test results.
AGC also proffers formulation tips
on achieving matte finishes with FEVE
based powder coatings. The incorporation
of 8 percent by weight of silicone
microparticles (Tospearl from
Momentive) produced a 60° gloss of
30 gloss units (GU). Impact resistance,
adhesion and UV durability were not
compromised by this matting technique.
The most common powder application technique involves electrostatically
charging the powder to facilitate attraction to a conductive
(e.g., metal) surface. It is, therefore, rare to encounter an application
to a non-conductive surface such as glass. A dynamic custom
coater in California has thought outside of the box to develop a
technique to powder coat glass bottles for high-end consumer goods
such as fragrances, nail polish and spirits. The company, Bottle
Coatings, Inc., is the brainchild of Shivie Dhillon and is a spin-off
of his primary business, SunDial Coatings. The success of Bottle
Coatings relies mainly on a patented two-coat process that allows
the powder to be applied evenly to the vitreous substrate. Glass
bottles are preferred to ceramic packaging as glass provides more
precise closure tolerances.
This innovative process blocks the entire spectrum of UV light,
including UVA, UVB and UVC wavelengths. Keeping UV light
out of a packaged product is critical to the shelf life of nail polish,
especially the higher end polishes that use UV energy to cure or
harden the finish. Initial attempts were made to filter the UV light
with inhibitors or absorbers; however, these materials eventually
lose their functionality and the contents of the bottle suffer. Dhillon
designed a technique to block UV light and therefore protect the
contents indefinitely. In addition to application consistency and UV
blocking, this process delivers chemical resistance to the aggressive
solvents, plasticizers and additives commonly found in nail polish.
A surprising number of this year’s innovations were introduced
by the raw material world. Many of the advancements are from
newcomer chemical suppliers focused on entering the powder
One of the most interesting developments is self-healing coating
technology by Autonomic Materials Inc. (AMI), whose products are
autonomic—which means that they repair themselves automatically
upon incurring damage. These products are microcapsules based
on core-shell morphology. The microcapsules are dispersed evenly
into the powder coating as a post-blend additive. The coatings are
applied conventionally and cured at conditions appropriate for the
thermoset binder. The initial work is based on epoxy binders.
Upon damage to the coating film, AMI’s microcapsules rupture
and fill the damage with a healing polymeric material. From a
functional perspective, this healing mechanism reseals the film
and thereby provides protection to the substrate from environmental
attack, specifically corrosion. Dr. Gerald O. Wilson, AMI’s
vice president of technology, has demonstrated excellent examples
of performance of damaged vs. “healed” films in ASTM B-117
salt fog corrosion testing. Coatings were applied to cold rolled
steel and scribed with a 500 micron-wide tool. Epoxy powder
coating films containing AMI microcapsules repaired the breach
in the coating and significantly outperformed the control powder
coating, which did not contain the microcapsules. The control
powder began to exhibit significant creep from the scribe after
about 750-hours salt fog exposure, whereas the formula modified
with the microcapsules resisted scribe creep until 4,000 hours in
the salt fog environment.
Dr. Wilson did his homework when characterizing the performance
of these microcapsules in powder coatings. He realized
that the additive had to maintain integrity during incorporation
into the powder coating. Concerns with rupturing the additive in
the extrusion process led him to add them via dry-blending after
the powder was made. In this process, the particles had to resist
agglomeration and sintering. Furthermore, the microcapsules had
to remain evenly dispersed throughout packaging and the elec-trostatic
application process. They designed the shell material to
carry a charge of polarity compatible to common powder coating
materials. Finally, the core-shell particles had to resist rupture at
high-temperature curing conditions typical for powder coatings.
The significance of this new technology is providing an
exceptional improvement in corrosion resistance without the
use of heavy metals, hexavalent chromium or other hazardous
compounds. These coatings not only exhibit acceptable initial
performance, but provide excellent barrier properties even after
sustaining significant damage down to the substrate.
Another recent approach to improved corrosion resistance
involves powder coating based on epoxy/clay nanocomposite.
Epoxy/clay (Closite 30B) nanocomposite samples were prepared
by using solution and melt dispersion methods. The quality of
clay dispersion in epoxy matrix was evaluated by using X-ray
diffraction (XRD) and transmission electron microscopy (TEM)
techniques. The prepared nanocomposite samples were used
in epoxy powder coating formulations (named as nano powder
coatings). DSC analysis was used to study the curing behavior
of samples. The physical, mechanical and thermal properties of
by using tensile,
analysis (TGA) and
loss on ignition
(LOI) tests. Finally,
the corrosion resistance of prepared epoxy nano powder coatings
was determined using the salt spray test. The results illustrated
that Closite 30B nanoparticles could be dispersed properly
in epoxy resin by melt dispersion methods. It was found that
Closite 30B could accelerate the epoxy curing reaction. The
results showed that the mechanical properties of nano powder
coatings improved when various concentrations of clay nanoparticle
(in the range of 1-5 phr) were used in formulation. It was
observed that sample with 3 phr clay nanoparticles presented
the best thermal- and fire-resistance properties. The salt spray
measurements confirmed the superiority of corrosion resistance
of epoxy nano powder coatings in comparison to that for neat
epoxy powder coating formulations.
Researchers also found that cerium tartrate can be used as
an inhibitor pigment for corrosion protection in epoxy coatings.
The efficiency of corrosion inhibition of a new pigment, cerium
tartrate, on aluminum alloy was studied. The results of release
measurements of Ce ions from epoxy coating in 0.05 mol/L NaCl
indicate that cerium ions are able to transport through the epoxy
coating, which is a key characteristic of inhibitor pigment. The
electrochemical impedance spectroscopy (EIS) shows that cerium
tartrate is an effective pigment for improving the barrier effect
of epoxy coatings on 2024-T3 grade aluminum. The self-healing
ability of cerium tartrate in artificial defects was verified by
scanning vibrating electrode technique (SVET). Cerium tartrate
played a self-healing effect at the defects in epoxy coatings.
Recent studies show that polyaniline grafted basalt plates
can improve the corrosion resistance of epoxy coatings.
Polyaniline-graft-basalt plates (PANI-g-BP) were prepared based
on ϒ-aminopropyltriethoxysiliane-modified basalt plates via
in-situ chemical-oxidation polymerization method. Three PANIg-BP
samples were prepared by varying the ratio of aniline to BP
(1:2, 1:4, 1:6). The results of Fourier transform infrared spectroscopy
(FTIR), scanning electron microscope (SEM) and TGA confirmed that
PANI was successfully grafted on the surface of basalt plates.
Different coatings were prepared by adding
the synthesized PANI-g-BPs or PANI, and were coated on the
mild steel subsequently. The water-uptake property, the adhesion
strength and the passive properties of the coatings were investigated.
In addition, the protective performance of the
coatings was tested by EIS (electrochemical impedance spectroscopy)
in 12 percent NaCl solution at 203°F (95°C). The results
indicated that the coatings with 10 percent PANI-g-BP (1:4) exhibited
the best protective performance and its impedance at 0.01 Hz
is higher than 1,010 after 80 days immersing.
A modified graphene oxide (GO) coating was found to reinforce
the corrosion protection properties of epoxy coatings. This
coating was prepared by anchoring a prepolymer of urea-formaldehyde
resin onto graphene oxide sheets through in situ polycondensation.
The modified graphene oxide sheets were characterized
by scanning electron microscopy, transmission electron microscopy,
X-ray diffraction experiment, Fourier transform infrared
spectroscopy, sedimentation test, and electrochemical impedance
spectroscopy. One major finding was that the superior compatibility
of UF resin with the epoxy resin retained the high dispersion
of modified GO sheets in polymer matrix. Results further revealed
that the modified GO sheets significantly reinforced the corrosion
protection properties of epoxy coatings on carbon steel substrate.
The Lubrizol Corporation announced the availability of new
additive technology for powder coating applications with the
development of a matting additive. PowderAdd 9553 is a novel
matting agent that provides consistently reproducible and uniform
matting. It is an easy-to-use additive that is highly efficient and
quickly turns glossy powders into matte powders. It can reduce
production costs and inventory requirements for small batch
manufacture. It works with all standard powder chemistries,
allowing for improved manufacturing flexibility.
Researchers found that the roughness and gloss of powder coatings
can be tuned with thin Al2O3 films. In this work a method was
found to change the surface finish of a standard polyester-based
powder coating from gloss to matte by depositing
ultrathin films of Al2O3 on the powder coating particles. The coating
experiments were performed in a fluidized bed reactor at 1 bar
and 81°F (27°C), using a gas-phase coating process of alternating
exposure of the particles to the two precursors (trimethylaluminum
and water), similar to atomic layer deposition (ALD). The number
of coating cycles were varied (1, 2, 3, 5, 7 and 9 cycles) to obtain
film thicknesses of the alumina shell ranging from 1 to 30 nm.
The average growth per cycle of the process is 3.5 nm, significantly
larger than the one for pure self-limiting ALD. When the
average alumina shell was thicker than 6 nm, the shell prevented
the flow of the core particles, even though the powder particles did
soften above its glass transition temperature. With the particles’
morphology intact, this resulted in a rough and matte surface finish
of the coating after curing. The surface roughness, with a value
around 9 μm determined by surface profilometry, is associated to
the alumina coated particles as observed with SEM and EDX analysis.
In addition, the matte finish coating showed mechanical resistance
similar to that of uncoated powder particles.
Powder coatings provide excellent film performance in a range
of harsh environments; however, the presence of polymers in their
composition increases the risk of combustion in adverse situations.
In this context, a study was made to develop and characterize
acrylic-based powder paints with the addition of 2 wt % and
4 wt % montmorillonite clays (MMT) as Cloisite 30B (MMT-30B)
and Cloisite 15A (MTT-15A), employed as flame retardants. The
characterization of the coatings was carried out by TGA, X-ray
diffraction, and scanning electron microscopy. After application
of the coatings on carbon steel substrates, flammability tests were
performed. The coatings with 2 wt % MMT-30B showed overall
better results, especially in the flammability tests. Flames spread
less on these coatings than on the other systems. However, when
the surface and bottom temperatures were analyzed by the cone
calorimeter test, the samples prepared with 4 wt % MMT-15A
were considered safer to be applied in fire scenarios.
Nouvex, a new antimicrobial polymer additive that was developed
by Purdue School of Materials Engineering and commercialized
by Poly Group LLC, has been approved by the U.S.
Environmental Protection Agency, Office of Pesticide Programs,
Antimicrobial Division as a material preservative. The technology
is used to prevent microbial contamination of textiles, thermoplastics,
water- and solvent-based coatings and powder coatings.
Poly Group intends to keep developing the technology aiming for
another approval from FDA and EPA.
The first new shade of blue in more than 200 years—discovered
via happenstance by a team of college scientists—soon will
be introduced to the coatings market. Shepherd Color Company
has reached a license agreement to market the first amount of
YInMn Blue pigment and is seeking business partners to explore
its commercial applications. According to Shepherd’s website,
YInMn pigment—named as such because it’s based on an oxide
made of yttrium, indium and manganese—can be used for artist
color materials; building products with high solar reflectance for
regulatory approval and reduced energy for cooling; or applications
where this particular shade of blue can be useful (high heat
and UV stability, infrared [IR] properties, and unique chemical
structure and composition).
In 2009, scientists at Oregon State University, led by Material
Science Department Chair Mas Subramanian, were exploring the
electronic properties of manganese when mixed with different
chemicals. When graduate student Andrew Smith heated black
manganese oxide, yttrium and indium to 2,000°F (1,093°C), a
compound with a striking blue hue was pulled from the furnace.
Energy companies have expressed interest in using YInMn
Blue because of its pigment structure. Oregon State says its IR
reflectivity is about 40 percent, and when used in roofing materials
could help keep a property cool and improve energy efficiency by
reducing the need for air conditioning.
As part of its “Cool Roofs” initiative, Shepherd Color
Company tested YInMn Blue’s IR reflective properties at its
Laboratory for Advanced Innovative Research, near Denver.
Using two house models, researchers used a standard dark
blue—made with high durability pigments—for one small,
metal-paneled roof, and a coating of YInMn Blue on another.
Both models were placed outside on a sunny, warm day. Using
an infrared imager to test each roof, it was revealed that the
standard roof was much hotter than the YInMn Blue model. The
imager’s temperature sensing function showed the
standard blue roof was 191°F (88°C); the YInMn Blue roof
was 168°F (76°C).
Cornelius Group has collaborated to deliver two extender
product solutions to market in the wake of the titanium
dioxide (TiO2) shortage. The company has partnered with VB
Technochemicals SA to offer VB White, which is suitable for
the masterbatch market, and with Huber Engineered Materials
to provide Zeolex 330 to the paint and coatings market. Huber
Engineered Materials’ Zeolex 330 is an amorphous sodium
aluminosilicate powder for paint and coatings applications. It
acts as a gloss sheen control agent and provides high levels of
opacity, whiteness and brightness as well as outstanding flatting
and scrub-resistance for interior architectural formulations.
Recently, the European Chemicals Agency (ECHA) proposed
labeling titanium dioxide as a potential carcinogen. Their position
is based on laboratory studies that demonstrate that rats can
develop malignant tumors when exposed to high doses of TiO2.
The International Agency for Research on Cancer (IARC) has
listed TiO2 as a potential carcinogen since 2006. Please note that
the terminology is a “potential” or “suspected” carcinogen and
not a “presumed” or “known” carcinogen. “Presumed” classification
is largely based on animal studies whereas “known” is based
on human evidence. The exposure route and mechanism are said
to be respiratory and due to oxidative stress and inflammation.
Where this proposal leads will have far-reaching effects on
the industrial coatings industry as well as decorative paints,
plastics, paper, cosmetics and even the toothpaste industry.
Titanium dioxide has been used as the primary white opacifier
in these end uses for more than 50 years. With this history,
it is interesting to note that not a single case of cancer has
been connected to exposure to TiO2. The Titanium Dioxide
Manufacturers Association (TDMA) contends that more than
24,000 workers in their industry have been exposed to TiO2
with nary an epidemiological link to cancer. They, obviously,
vehemently oppose such a regulation.
From a powder chemist’s point of view, this would turn
our formulations upside down. I would conservatively estimate
that over half of all powder coating formulas have at least
some titanium dioxide. Alternate white opacifying pigments
all fall woefully short of TiO2’s efficiency in making things
white. Rutile TiO2 has the highest refractive index of any white
mineral, which, in turn, provides the most efficient hiding.
Hopefully the EU will carefully solicit industry experts and
business stakeholders for their input on which direction to
choose whilst maintaining the safety of workers and the general
When the internal epoxy powder coating of land surface oil
pipeline (LSP) in Kuwait was completely detached, curling from
the substrate, and the production flow line was plugged with
the deposit of paint debris after one year of operation in service,
the failure was identified by differential scanning calorimetry
(DSC) and other surface analytical techniques as curling caused
by the improper curing process of the powder coating materials.
But, the question of why there was this failure was not
In a recent study by the Construction and Building Materials
Program, Energy and Building Research Center, Kuwait Institute
for Scientific Research, an experimental investigation was
carried out using electrochemical impedance spectroscopy (EIS)
by employing a new test cell to find out the reason behind the
failure of the internal coating. The EIS was used to analyze the
causes of failure of two different batches of the same coated
piping—as-received epoxy coating and the failed one—by simulating
the necessary environment and operation temperature.
The EIS results with the new test cell indicated the compliance
of the technique in confirming the hypothesis about the poor
quality of the powder coating process and adhesion loss failure,
obtained by the DSC, using FTIR, and X-ray photoelectron
spectroscopy (XPS) techniques. The study confirmed that the
quality of coating could be identified through the impedance
value of the intact and failed coatings
The year 2017 offered a host of advancements for the
powder coating industry—from commercialized trends
to emerging technology in raw materials, pigments and
instrumentation. Most interesting is that the source of many
of these innovations emanates from new entries to the powder
coating industry. We are finding eager researchers who recognize
the potential to improve powder coating technology and at
the same time envision a path to eventual commercialization.
These new developments bode well for our industry.