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Direct to Substrate Trend --
One Paint That Does the Job of Two
Most professional painters have subscribed to the fact
that choosing the right paint and pursuing proper
surface preparation are critical steps in delivering a
quality finish and minimizing pre-mature paint failures. In many
cases, a suitable primer has to be used. Today’s primers are
uniquely optimized to deliver adhesion to various surfaces, or
to seal surfaces and block specific stains. Recently, we see
advances that allow both primer and topcoat attributes to
be wound into one package. This new trend is sometimes
referred to as Direct to Substrate (DTS). We will show that the
perfect finish, which resulted from a select primer plus 2-coats
of a quality topcoat, can now be replaced by 2-coats of a
quality DTS. The value proposition for professional painters
and consumers alike is straightforward – one less coat (labor
plus material) needs to be applied!
On using primers: Today’s primers are optimized to deliver
superior performance on selective surfaces. Consumers and
contractors alike are fairly familiar with some of the primers
on the market – e.g. drywall primers (for painting over fresh
drywall); stain blocking primers (for blocking tannin stains in
wood); and even metal primers (for inhibiting corrosion in
applications over bare metal).
Primers are designed to serve many purposes. They seal
the substrate to be painted allowing for more efficient and
uniform coverage with a topcoat. Primers also serve as a
tie layer – providing optimum adhesion to the substrate and
providing a compatible surface for the topcoat to stick. As
new substrates and building practices evolve, we see primers
evolving to enable a desired effect – for example, helping to
accentuate the smoothness or roughness of a surface. And
as we mentioned above, primers are also optimized to block
stains (particularly tannins in wood).
Not all primers are created equally: We illustrate this in the
two figures below. In Figure 1, we show durability performance
for two coats on yellow pine. The panel shows five segments
each representing 2 coats. The first two segments are primers
with no top coat. The next two panels show the primers topcoated
with a quality acrylic paint. The paint on the far right
is a crack (fail) control. We also show the impact of binder
chemistry – alkyds not only tend to yellow but continue to
crosslink, becoming rigid and cracking as the film ages. Figure
1 also shows that traditional primers are not optimized for
long term durability, hence, little surprise that a primer and
Figure 1: Primers – utility and type on yellow pine.
| pdca.org
Contributed by Rohm & Haas
topcoat outperforms 2
coats of primer.
Best Option – High
Quality Primer: A
more impressionable real
world application is captured
in the shutter images.
Performance over a
3-month weathered vinyl
shutter is shown -- this is a typical repaint opportunity. The image
on the left shows 2 coats of topcoat without primer while
that on the right has one coat of primer plus one topcoat. The
primerless finish is inferior and shows severe blistering. PQI
and most manufacturers recommend a primer plus 2 coats
of topcoat to ensure the best coverage and adhesion and to
maximize durability and appearance.
2-Coats Topcoat (No Primer)
Primer + 1-Coat Topcoat
Direct to Substrate
Trend: What
if a technology can be
developed that brings
the best properties of
the topcoat (e.g. durability
and appearance)
with that of the primer
(e.g. adhesion and
stain blocking)? This is
in fact the case today.
More manufacturers
are introducing these
direct to substrate
(DTS) paints that deliver excellent performance from a single
can. That is, as opposed to using a primer followed by 2 coats
of a topcoat, the same performance can now be delivered with
2 coats of a DTS paint. We highlight two examples below that
clearly demonstrate that both topcoat (durability) characteristics
and primer (stain blocking) characteristics can now be built
into the same binder. The figures below show that two coats
of a DTS outperform 2 coats of top quality acrylic paint or a
primer plus topcoat for
stain blocking. And at
the same time, the DTS
has equivalent exterior
durability. We anticipate
that the use of these DTS
paints will be a growing
trend in the market and
would bring real value to
contractors as they can
now deliver the perfect
finish with one fewer
coat of paint.