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H Don McBride of Heucotech says that
companies can offer a wide-ranging
product palette that still complies with
regulations and offers the same high
performance quality.
In your view, what are the most useful
organic and inorganic high perfor-
mance pigments, or HPPs, and why?
Don McBride: The investment in our own
Indanthrone crude plant to supply the
vital ingredient for this popular automotive transparent red shade, PB 60, will
enable us to control both the quality and
the consistency for the crude that is key
to our latest polycyclic technology. The
H A new ASTM standard for xenon
arc weathering of coatings has been
published. As Sean Fowler, technical
marketing specialist at Q-Lab explains,
development of useful accelerated test
methods relies on data produced in
outdoor tests.
What are the latest trends in acceler-
ated weathering testing of coatings?
Sean Fowler: Just this year, a new ASTM
standard for xenon arc weathering of
coatings, D7869, was published. This
“The Move to No-VOC Universal
Colorant Systems”
HIGH-PERFORMANCE PIGMENTS ARE PROMISING
“Outdoor Testing is the Backbone of
Weathering Testing”
DEVELOPMENT OF USEFUL ACCELERATED TEST METHODS RELIES ON DATA PRODUCED IN OUTDOOR TESTS
various grades of Diketopyrrolopyrrole
(DPP) reds provide formulating latitude
for both coating and ink manufacturers to
use these PR 254’s in increasing applications due to performance and efficiency
in use. Recent inroads made by the DPP
technology can be found in colorant systems for architectural paint, and in metal
deco and silk screen inks.
Where do you see the greatest growing
market areas for HPPs?
Don McBride: Bismuth Vanadate, P Y 184,
is well known as a clean and brilliant yellow used in automotive and industrial
coatings. The encapsulation of this yellow enhances several resistance properties of this very durable pigment: thermal, acid, alkali and SO2. This special
treatment lets us use PY 184 in coil and
powder applications. We are pleased with
new products in the R&D pipeline that
will provide higher tinting strength for
conventional and encapsulated grades of
bismuth vanadate in the near future. Cobalt blues (PB 28 & PB 36) offer an array
from red shades to green shades to hues
of blue, and along with Cobalt Greens (PG
new standard is based on 10 years of research by a coalition of automotive and
aerospace OEMs (Ford, Honda, and Boeing), coatings suppliers (BASF and Bayer),
and weathering chamber manufacturers
(Q-Lab and Atlas). For the first time, a single laboratory weathering cycle was able
to correlate to outdoor Florida results for
several degradation mechanisms. One of
the key new features of ASTM D7869 is a
method to measure the amount of water
spray delivered to test specimens, along
with a minimum requirement.
Can accelerated testing exist without
outdoor testing or can they be corre-
lated?
Sean Fowler: Outdoor testing is the back-
bone of weathering testing. Development
of useful accelerated test methods relies
on data produced in outdoor tests, as in
the example of ASTM D7869. The only
way to know if an accelerated test is giv-
ing meaningful results is to compare it to
outdoor weathering data to determine if Spray sponge chamber
Don McBride,
Heucotech
Sean Fowler,
Q-Lab
Corporation
50), they offer excellent lightfastness
and chemical resistance. The rutile yellows (PY 53) and rutile browns (PBrn 24)
offer tremendous opacity and resistance
properties for industrial finishes. The spinel blacks and browns, PBrn 35 and PBlk
28, offer high temperature alternatives
and IR-reflecting properties with excellent resistance characteristics.
The ecotoxicology of some of these pig-
ments is particularly crucial. How does
that factor in with these pigments in re-
gards to substitution and other issues?
Don McBride: The aforementioned HPPs
are offered in liquid preparations for the
coatings industry in environmentally
a correlation exists. A useful accelerated
test requires a compromise between
speed and realism, and you need outdoor
data to figure out which parameters you
can turn up in the lab without spoiling the
results.
What challenges remain in accelerated
weathering testing?
Sean Fowler: Weathering chambers are
essentially designed to break things. The
challenge is to break them quickly in a
repeatable and reliable manner such that
the pieces look the same as they would
after months, years, or decades out-
doors. The “things” we’re talking about
are typically complex material formula-
tions involving many interacting mole-
cules. It’s useful to think of a weathering
chamber as a series of control levers for
light, heat, moisture, and transitions be-
tween various conditions of these three.
It takes a concerted effort to determine
how best to adjust these levers to create
a good accelerated test for a particular
friendly colorant systems. Of late, the
more interesting development in North
America has been the move to no-VOC
universal colorant systems. This includes
being able to utilize most of the pigments
discussed here as additional high-per-
formance options as the canister count
moves to 16 and beyond. While this
trend has existed in Europe for years, it
is also becoming more common in North
America as paint companies seek a way
to stand out from the competition.
class of materials. Unfortunately, these
levers usually must be adjusted differ-
ently for each class of material.
