Table 3. Typical Staining Agent Testing
Barbeque Sauce
Balsamic Oil
Spaghetti Sauce
Mustard
Balsamic Vinegar
Ammonia
Used Motor Oil
Transmission Fluid
WD- 40
Brake Fluid
Coke Cola
55% solids
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
45% solids
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
35% solids
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
Pass
25% solids
Marginal
Marginal
Pass
Fail
Marginal
Pass
Marginal
Fail
Marginal
Fail
Pass
Discussion
The testing revealed that the sealer pre-
vented discoloration or gloss change of
the concrete substrate when it was ex-
posed to a variety of staining or corrosive
substances commonly encountered in the
decorative flooring market. Many of these
staining agents would cause disbondment,
discoloration, or milking of traditional
acrylic sealers.
4 The percentage of resin
solids was investigated since there is such
a wide range of porosity in the different
types of decorative concrete surfaces –
polished, stained, densified, or a combina-
tion of these treatments. For projects
where the concrete has been polished to a
lower grit level, for example 500-800 grit,
the preference is to use a higher solids
level which will fill micro pores and be
more readily absorbed into the substrate.
This is often the preferred method for acid
stained concrete as well. For higher pol-
ished floors, 1500 grit or higher, or floors
that have been densified, the standard
guide formula can be modified to a lower
solids content in order to help with pene-
tration into the tighter concrete surface.
This is achieved either by:
- Thinning a commercially available
two-component waterborne polyurethane
system with distilled water to the needed
target solids content
- Purchasing a commercially prepared,
lower solids two-component waterborne
polyurethane system specifically formu-
lated for tighter concrete applications
The preference of this author is for the
second choice above for several reasons.
First, the correct dilution rate is done by the
manufacturer in a controlled environment
which ensures the accurate and desired
amount of resin is installed on the surface.
Second, field dilution could possibly be
done with water containing solids, iron, dissolved salts, or other contaminants that can
affect the final properties or cure time of the
system. Third and most important, a specifically formulated lower solids coating/sealer
system will still contain the proper amount
of the other necessary components such as
flow and leveling aids, bubble breaker additives, surfactants, and other additives that
are necessary to ensure an easy application,
good wet out, and the desired aesthetically
pleasing look, as well as the required final
physical properties.
Conclusions
Polyurethane-based sealers offer a step up
in stain resistance while protecting against
corrosive agents such as organic acids.
During application, this novel two-component waterborne polyurethane coating penetrates effectively, without objectionable
odor. The sealer technology offers contractors and owners a long-term solution for
protecting their decorative concrete investment while preserving the pleasing aesthetics of these ornate works of art. CW
Acknowledgements
The author extends his appreciation to the
colleagues who were involved in the testing, data creation, and general consulta-
tion during the research and summary of
these unique technologies: Kathy Allen,
Jeanette Eastman, and Chris Sullivan.
References
1. Reinstadtler, Steven, “Intelligent
Concrete Coating Solutions for Sustainable Construction”, CPI conference proceedings, 2009.
2. Wuehrer, Karl H.; Allen, Kathy,
“Chemical Resistant Waterborne
Polyurethane Topcoats for Flooring”,
Journal of Protective Coatings & Linings,
2007 24(2), pg. 58-66.
3. K. Allen and P. Schmitt, “Greener
Gambits in the Antigraffiti Game”, Journal of Architectural Coatings May 2009,
pg. 38-47.
4. Interviews with professional flooring contractors in the decorative flooring
industry, 2010-2011.
Steven Reinstadtler is the industrial marketing manager for Bayer MaterialScience’s
Coatings, Adhesives and Specialties Division in Pittsburgh, Pa. He holds a BS degree in Chemistry with a Polymer Science
option from the University of Pittsburgh.
Steven joined the Polyurethanes Division of
Bayer in 1987 as a chemist working on
high performance prepolymers and spray
elastomers. He transitioned into the Coatings Division in 2006, where he was responsible for the research activities of the
Construction Coatings group as well as
forward marketing activities. Steven is currently responsible for identifying new
polyurethane coatings
