In Polyurea (PUA) the cross-linking reaction takes place solely between the isocyanate and the amine-terminated compounds.
Hydroxyl groups added through additives or pigment pastes should not have a significant influence on the cross-linking reaction.
Humidity cross-linking and humidity activated polyurea based reactive polymers are not PUAs within this dention.
This distinguishes polyurea from polyurethanes and polyurethane-polyurea hybrids where the crosslinking takes place between the isocyanate and hydroxyl-terminated compounds.
The significantly faster reaction between isocyanates and amino groups over hydroxyl groups and the higher thermal and hydrolytic stability of the urea over the urethane bond leads to the unique properties of polyurea.
Polyurea-based products are characterised by their high performance and are therefore used in various application areas worldwide.
Formulation and the resulting performance characteristics of polyurea products are adjusted for the respective application areas.
They typically have the following advantages in spray applications:
Polyurea hybrid relative humidity source: Huntsman temperature 0°C 0% PU price/quality compromise, boundaries to be dened extreme properties reactivity,
cold cure react, set and cure quickly – treated surfaces can return to service fast or be further processed in just a few hours;
can be used in a wide temperature and humidity range (larger application window);
have high thermal resistance and good low temperature flexibility;
have outstanding mechanical and chemical resistance;
are hydrolysis stable and insensitive to water;
color stability is possible (aliphatic systems);
do not contain solvents (100 % solids);
form flexible, seamless and elastic lms;
because of the fast reaction speed, even vertical surfaces can be coated in any desired layer thickness in one pass (seamless, three-dimensional waterproofing);
adhere well to all substrates;
do not need catalysts which results in a further improvement of the hydrolysis stability.
Hand-applied polyurea systems have most of the properties listed above and are complementary to spray systems.
They are used as top coats and/or repair coats. Essential differences are their slower reaction time,
the possibility to be applied by hand, and the occasional use of solvents.
TYPICAL PHYSICAL PROPERTIES
MPa 10 – 30
A 30 to D 65
% up to 1000
Tear Strength, N/mm
20 to 125
100% Modulus, MPa
3.5 to 15
150 – 500
(-26°C/-15°F) >3 mm
Aromatic Based Spray Formulations
Standard systems with good overall performance
Limited color stability in outdoor applications
Aliphatic Based Spray Formulations
Excellent color stability in outdoor applications
More costly than aromatic based systems
Slow Cure Joint Sealants Brush Grade Systems for Top Coats and Repair Industrial Adhesives Systems with CE labelling are available