Chemistry in brief
Conventional polyurea forms when an isocyanate reacts with primary amines. The reaction is so fast that it requires plural-component spray equipment. Polyaspartic esters are hindered secondary amines that react more slowly with the isocyanate, which gives a usable working time while keeping a fast overall cure. Because both components are aliphatic, the film does not yellow or chalk the way aromatic epoxies do in sunlight.
How it compares
| Property | Polyaspartic | Epoxy | Aliphatic polyurethane |
|---|---|---|---|
| UV and colour stability | Good | Poor, chalks and yellows | Good |
| Cure speed | Fast | Moderate to slow | Moderate |
| Application | Roller, squeegee or spray | Roller, squeegee, trowel or spray | Roller or spray |
| Typical role on floors | Topcoat or full system | Primer, body coat, topcoat | Topcoat |
| Typical role on steel | Topcoat, some direct-to-metal products | Primer and intermediate | Topcoat |
These are general trends. Abrasion, chemical resistance and film build vary widely between formulations, so comparisons are made on data sheet values measured by the same methods, for example ASTM D4060 for abrasion.
Where it fits
- floor topcoats over epoxy where quick return to service or UV stability is needed;
- loading docks, entrances and areas exposed to daylight;
- topcoats on structural steel and equipment in atmospheric exposure, within systems compatible with ISO 12944 requirements;
- maintenance work with short shutdown windows.
Limits and precautions
- Short pot life. Fast cure means small batches and an organized crew.
- Humidity and temperature. Moisture and heat change the reaction rate and can cause bubbles or surface defects; the data sheet sets the limits.
- Substrate preparation. Concrete needs the specified concrete surface profile and acceptable moisture, as for any resin floor. On steel, the primer and preparation grade come from the system specification.
- Not a universal replacement. For immersion or severe chemical service, other chemistries may be required.
Because the product cures quickly, a test area is useful to confirm workability, appearance and adhesion under actual site conditions before full production.
Adhesion on concrete is checked per ASTM D7234 and on steel per ASTM D4541 when specified. See our industrial epoxy flooring and polyurea coatings services.