Side by side
They share a parent and a lot of strengths. The differences show up in how fast they cure, what conditions they tolerate and what it takes to apply them.
Isocyanate + amine resin
Fast, tough and tolerant of cold and damp.
Strengths
Watch for
Isocyanate + polyol resin
Versatile, workable and easy to finish well.
Strengths
Watch for
Isocyanate + amine and polyol blend
A blend that sits between the two.
Strengths
Watch for
General tendencies. Individual products vary, so the data sheet has the final say.
| What matters | Polyurea | Polyurethane |
|---|---|---|
| Reacts with | Amine resin | Polyol resin |
| Cure speed | Seconds to gel | Minutes to hours or longer |
| Working time | Almost none | Enough to roll and level |
| Moisture and cold during cure | Tolerant | More sensitive |
| Film per coat | Thick builds in one visit | Usually thinner coats |
| Flexibility | High elongation grades common | From flexible to hard |
| Sunlight | Aromatic darkens, aliphatic holds color | Aromatic yellows, aliphatic holds color |
| Typical equipment | Heated plural component rig | Roller, brush, airless or plural component |
| Common uses | Liners, roofs, tanks, containment, floors | Foam, floors, topcoats, cast parts |
In short
Polyurea reacts in seconds, builds thick films in one visit and copes with cold and damp, but it needs a heated plural component rig and a trained crew. Polyurethane gives you time to roll and level, works with simpler tools and comes in foams, elastomers and topcoats, but it is more sensitive to moisture while it cures.
Many systems use both: a polyurea base for build and protection with an aliphatic polyurethane topcoat for color. See the chemistry, or answer five questions in the coating selector.