Polyaspartic ester (PACM-based tetraethyl ester)
The secondary-amine resin that makes polyaspartic coatings possible: fast-curing and UV-stable, yet slow enough to roll on.
Aspartic esters are made by adding a diamine to a dialkyl maleate, producing a secondary diamine flanked by ester groups. The profiled grade here, based on 4,4′-diaminodicyclohexylmethane (PACM) and diethyl maleate, is sold as Desmophen® NH 1420 and equivalents, with an amine equivalent weight around 276 g/eq. Other grades use different diamines to change speed and hardness.
Aspartic esters form the B-side of polyaspartic coatings, reacting with aliphatic polyisocyanates such as HDI trimer. They are used for one-day garage and commercial floors, clear and pigmented topcoats over epoxy or polyurea, and corrosion-protective topcoats.
Each nitrogen carries one reactive hydrogen. Steric bulk and the electron-withdrawing ester groups slow the amine–isocyanate reaction from seconds to minutes, giving usable pot life while keeping fast cure. The choice of diamine backbone sets reactivity. Aspartic ureas can also slowly cyclize to hydantoin structures.
Aspartic esters can irritate skin and eyes. Mixed systems contain aliphatic isocyanate and require isocyanate precautions. Keep containers closed and dry.
The aspartic ester’s secondary amines are crowded by ester groups, which slows their reaction with isocyanate enough to allow roller or squeegee application.
Yes. Both the aspartic ester and the aliphatic isocyanate hardener are free of UV-absorbing aromatic groups, so polyaspartic films resist yellowing.
