Bayer MaterialScience LLC has developed new, fast-setting polyurea sealants, which feature qualities such as improved UV stability and superior physical properties demanded in high productivity joint filling applications. Such qualities are particularly important for settings such as “big box” stores where hard-wheeled vehicles repeatedly pound across the edge of concrete joints, often breaking the seams and damaging the concrete floor.
Dr. Jay Johnston, Senior Associate Scientist, Bayer MaterialScience LLC,
presented a paper on current state-of-the-art polyurea sealants and discussed
new optimized formulations using commercially available amines during the
Thermoset Resin Formulators Association’s (TRFA) annual meeting September,
2009, in Pittsburgh.
Johnston, who was also the conference chair, shared his findings in a
presentation based upon a technical paper he co-authored with Sandy Zielinski,
retired technician, Bayer MaterialScience LLC, titled Aliphatic 2-Component
Polyurea and Hybrid-Polyurea-Polyurethane Sealants..
Polyurea sealants are increasingly specified in the marketplace because of
their improved performance characteristics relative to competitive products.
They increase productivity because they are a faster curing system and they
have the ability to cure in cold conditions. These factors increase the
productivity of the final applicator in terms of time to complete the job and
extension of the working season. These sealants can also be used in industrial
refrigerators and non-conditioned settings.
The objective of the research was to develop an aliphatic polyurea sealant that
had physical properties and performance characteristics similar to aromatic
polyurea sealants. Samples of aromatic polyurea sealants, aliphatic polyurea
sealants and aliphatic hybrid sealants were prepared, and their physical
properties were tested and evaluated. Johnston also compared the various
sealants’ ultraviolet (UV) resistance, solvent resistance and low-temperature
Previously, first-generation polyurea sealants had one shortcoming – they would
discolor when exposed to UV light. This can be partially addressed through the
use of aliphatic aspartic esters in place of aromatic amines in sealant
formulations. Combining aspartic ester amines with a low-monomer-content
aliphatic prepolymer results in sealants with dramatically improved UV
stability, as well as superior physical properties and long gel times,
according to the Bayer MaterialScience researchers.
Development of an aliphatic prepolymer that can be used to prepare polyurea
sealants has taken the technology one step further. Johnston explores the use
of low monomer content aliphatic prepolymers to prepare sealants that exhibit
minimal color change when exposed to UV light. This solution is also a
considerable improvement over the use of rigid epoxy resins to protect concrete
joints; the lack of flexibility in the epoxy can lead to internal stress and
eventual failure of the concrete slab.
“The improved UV stability is achieved without sacrificing the sealant’s other
physical properties. The use of an all aliphatic sealant is especially ideal
for applications where aesthetic qualities of the sealant are important,” said
Johnston, noting that overall, the polyurea sealants demonstrated superior
technological performance over competitive products, making them the material of
choice for applications requiring high productivity joint
Bayer MaterialScience LLC is one of the leading producers of polymers and
high-performance plastics in North America and is part of the global Bayer
MaterialScience business with nearly 15,100 employees at 30 sites around the
world and 2008 sales of 9.7 billion euros. Business activities are focused on
the manufacture of high-tech polymer materials and the development of
innovative solutions for products used in many areas of daily life. The main
segments served are the automotive, electrical and electronics, construction,
medical, and sports and leisure industries.
For more information about Bayer MaterialScience’s coatings and sealants
technologies, call 412/777.3983, e-mail email@example.com or visit