These alternating hard block/soft block polymer units are linked by DETDA, which is commonly referred to as the "chain extender" of the system.
The "Polyurea advantage"
Polyurea elastomer coatings offer many advantages over their traditional counterparts (i.e. polyurethanes, polyurethane-urea hybrids).
The following list highlights a number of polyurea’s advantages.
- Fast cure. Polyurea can be sprayed on sloped (and even vertical) surfaces without drip or run formation. Foot traffic can resume on coatings applied to horizontal surfaces within 30 seconds.
- Water insensitivity. Relative moisture and temperature insensitivity during application. Little effect is encountered on adhesion or coating performance due to weather variations (i.e. high humidity, temperature and residual moisture).
- 100 % solids. Two-component, one-coat system can be sprayed and poured at 1:1 volume ratio. Eliminates the need for multi-coat applications. It is environmentally friendly.
- Excellent physical properties, including tensile strength, tear strength and elongation.
- Thermal stability. Stable up to 150 deg.C.
- Pigment compatible. Colorants can be added to change appearance and light-stability.
- Formulation flexibility. Can be formulated into products ranging from soft to hard elastomer.
- Reinforcible fibres and fillers can be incorporated during application.
The concept of instant, high-performance coatings has attracted the interest of many who possess an entrepreneurial spirit, as well as those with vivid imaginations.
In the infancy of this new polyurea technology, spray applications of structures and objects too numerous to fully list, were attempted. As already mentioned, the reaction of the isocyanate component with the amine blend is generally a very rapid, predictable reaction. The fast reactivity allows for rapid return to service for coating application work.
The current polyurea technology allows the preparation of both aromatic and aliphatic (light stable) elastomer systems. By selecting the appropriate isocyanate component and amine blend, a variety of system reactivities is possible. Slower systems can be utilised for a variety of sealant/caulk-type applications.
Given these attributes, polyurea elastomer systems are well-suited for a myriad of application areas including pipeline coatings, secondary containment, synthetic stucco coatings, concrete coatings, railcar coatings, foam and EPS coatings, tank linings, part production, truck bed liners, various waterproofing applications and floor joint/seam sealants.
In addition to these uses, polyurea continues to be evaluated for use in numerous niche applications that require high performance coatings with near-immediate return to service.
Recent European projects cover applications such as trading hall flooring, secondary containment in harbour areas, anti-abrasion coatings on sieves, pipeline coatings, road marking, truck bed lining.
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