1. technology and computing

Auto Body
Finishinp;
a
Three top paint suppliers rewieW the
industry’s p m p s s toward higher
performume and lower emissions.
Tim Triplett, Senior Editor
T
oday’s cars look better and last longer
as a result of continuing research and
development by automotive coatings
suppliers. Recent R&D efforts have yielded
new powder primer-surfacers, improvements
in waterborne basecoats and more etchresistant clearcoats, according to three of the
industry’s largest coatings companies.
“The automotive coating of the future will
be an electrocoat, plus a primer-surfacer,
waterborne basecoat and powder clearcoat.
That is clearly the direction,”saysJames Meier,
director of technology for automotive products at PPG (Cleveland).
Waterborne technology has made major
inroads in the automotive industry in the past
seven years, Meier says. In the 198Os, efforts
to remove solvent and increase the solids
content of coatings reached a level where
the finish quality was in danger of being
compromised.
“Environmental regulations required us to
reduce VOC emissions. The conversion to
waterbornes gave us a way to do that without
sacrificing any appearance,” he says. Waterborne technology is maturing and can no
longer be considered “new,”he adds, though
its chemistry and application are continually
being refined.
According to industry statistics for North
America, the first plant to apply a waterborne
W & POWDER-4/96
basecoat was commissioned in 1989. As new
plants have been built or upgraded since then,
most have added waterborne paint lines. Virtually all the major automakers now use
waterbornes to one degree or another. An
estimated 25% to 30% of all new cars now
sport waterborne basecoats.
Most industry experts agree that every auto
plant will eventually apply waterborne
basecoats because of their inherent environmental and quality benefits. “It won’t happen in the next five years, but as assembly
plants get older and are retrofitted, and as
new plants are built, they are all being designed to handle waterbornes,” Crawley says.
In addition to basecoats and E-coat,
waterborne chemistry recently made its first
appearance in the United States as a primersurfacer. BMW is now using waterborne
primer technology at its new plant in
Spartanburg, SC, where it applies 18 different primer colors to coordinate with the color
of each car. (See “Painting Bond’s BMW” in
this issue.)
“Waterborne primers have not really
caught on, primarily because of the added
investment required to convert from a
solventborne to a waterborne system,” says
Larry Crawley, director of automotive OEM
finishes technology for DuPont (Troy, MI).
“It’s been much easier to meet the environ-
mental regulations by increasing the solids variety of options. For the facilities where it
or adding abatement equipment, rather than has been introduced, given the conditions at
to convert to a new technology like water- that point in time, powder happened to be
the best option.”
borne primer-surfacer.”
Frank de Sostoa, director of planning and
Like with waterbornes, converting to powder coatings requires an expensive invest- market analysis for the OEM Coatings Div. at
ment in new finishing and curing equipment. BASF (Troy, MI) notes that powder is not a
Five to 10 years ago, some automakers began cheap solution to the chipping problem. It
applying powder to lower body panels as an also has limitations, such as the impracticalantichip coating. Today, powder primer- ity of color changes. Color-coordinating the
surfacer for antichip protection is being ap- primer and basecoat as BMW is doing would
plied to the entire car body at some plants. be impossible with powder today.
“Powder has its piece of the automotive
Crawley says powder primer-surfacer use
is probably the most significant change in coatings business, not necessarily for durabilautomotive coatings in recent years. Powder ity or enhanced appearance, but more for its
is being introduced in new plants by compa- tighter rein on emissions. For plants that have
nies that have traditionally put the basecoat run up against a permit limit on solvent emisdirectly over the E-coat, ,dnd not used a sions, powder may be a good solution, but it is
primer-surfacer at all. That means this tech- not a panacea for the industry,” de Sostoa says.
Powder clearcoats that offer better acidnology represents an entirely new layer of
protection on these vehicles, with no addi- etch resistance are under development by
the Low Emissions Paint Consortium, a joint
tional VOC emissions.
“The driving force is to address the envi- research venture sponsored by the Big Three
ronmental issues while improving chip resis- automakers.
“Powder clears are not really commercial
tance and quality,” Crawley says. “There are a
Robots and
automated
reciprocators apply
a powder primer to
truck bodies at the
GM Moraine
assembly plant. Use
of powder primersurfacers is on the
increase as
automakers strive
for better chip
resistance. (Photos
courtesy of DuPont)
4/96-INDUSTRL4L PAINT & POWDER 21
yet, but if we talk about where the market is
going in the future, powder clear is where we
want to be," Meier says. He estimates North
American automakers will begin to use powder clearcoats sometime between 2000 and
2003. "It is a matter of fitting the current
products with the process, which is what the
LEPC is working on now," he adds. BMW
recently began applying powder clearcoat at
its Dingolfing, Germany, plant.
Meanwhile, paint makers continue to find
ways to decrease the solvent and increase the
solids levels of solventborne coatings. DuPont,
to cite one example, is working on a superhigh-solids coating designed with a proprietav
polymer. The coating will be at least 70% solids, compared to the 50% to 55% solids levels
of today's conventional high-solids.
DuPont is planning to position the product, which should be commercial around the
New Special Effects Almost 'Mystical'
the viewer sees a new color.
Although Mystic onlyrecentlybecame commercially
available,BASFbelievessuch coatingswill eventually command a substantial share of the color
market. "In just a few years, many vehicles will
be covered with prismatic coatings," says Frank
McKulka, WF's group vice president for
automotive OEM coatings. "We are antici-
product of a'cooperative effort between
Ford Motor Co., BASF and pigment
hind these interference pigments involves a combination of constnictive and destructive light interference.
"Color-shifting interference pigments are creating very
exciting, potentially revolutionary, new color possibilities for automotive color," says John Hall,chief color
designer at BASF's Automotive Coatings Research Center in Southfield, MI.
Conventional automotive paint pigments exhibit
color by selective absorption, diffuse reflection and
scattering of light. A transparent blue pigment, for
example, reflects blue wavelengths of light in the visible
spectrum and absorbs wavelengths in the other areas of
the spectrum. With ChromaFlair pigments, color is
22 INDUSTRIAL PAINT & POWDER-4/96
rence pigments are made of
alternating layers that reflect or refract incoming light
rays. The outermost layers consist of transparent metal,
while the inner layers are made up of dielectric materials and a metal reflector.
To generate or "construct" Merent reflective color
combinations, Flex Productscontrolsthe materials that
make up each layer, the layer thickness and the
refractive index or reflective property of each
layer. The high degree of production control is
accomplishedin high-vacuum deposition chambers in a process called vacuum roll coating.
This type of light interference technology
offers the potential for consumers to choose
the exact color combination that pleases
them-a car that changes from emerald
green to gold, or a minivan that changes
from cobalt blue to fireballred, Hall says.
BASF is not the only paint supplier
that is working on new specialeffect
technology. "We are looking at putting all kinds of daerent coatings on
aluminum or mica flakes, or other
types of flakes," says James Meier, director of technology for automotive products at PPG.
For example, his company has experimented with
photochromic materials that changc color depending
on the lighting conditions, much like some eyeglass
lenses. Temperaturesensitive materials have been tested
'aswell, offering the prospect of ve
appearance with the seasons.
"Youwill continue to see specialeflkctcolors used in
niche markets," agrees Larry Crawley, director pf automotive OEM finishes technology at DuPont, "There is a
tremendous amount of work going on in the particle
industry to provide these new and unique color^."
Automotive coatings year 2000, as an alternative to powder, Crawley
suppliers are
says. “Our thinking is that if we can offer a
working to improve
product
with lower VOCs that can be used
the etch resistance
with
the
capture
and incineration equipment
of clearcoats, such
as the one being
already installed in most assembly plants, the
at a
auto cbmpanies would be very interested.”
GM plant, so they
Besides developing new coatings chemisstand up better to
tries,
paint makers must continually keep
environmental
hazards such as
abreast of new application technology. This
bird
and
creates a chicken-egg dynamic in the maracid rain.
,
I
ketplace; in other words, which comes first,
the paint or the spray gun?
“What the automakers are buying is not so
much paint, but the painted vehicle,” observes
Meier. “If a new piece of equipment comes
along, we have to reformulate to fit it.”
The auto industry’s transition from airatomized spray, to air-atomized electrostatic,
to bell electrostatic application is a classic
example, he adds. “The principle in all cases
was to improve transfer efficiency and get
more paint on the vehicle. But the requirements for the paint are substantially different
in terms of the way it atomizes, its conductivity,
the speed of solvent evaporation, etc.”
In the final analysis, paint suppliers agree,
it is not environmental regulations or new
technology that drive innovation in the auto
industry. It’s the consumer.
“If I look at a car’s engine, I can’t tell how
well it will run. But if I look at the hood and
see a flaw in the paint, I might not buy that
car,“ Crawley notes. “The value of the finish
on a car is a relatively minor portion of the
cost of the vehicle, but it has an abnormally
high impact on the ultimate consumer.” 0
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