Characteristics of Acrylic Polyurethane Topcoat

Acrylic polyurethane paint, formed by the reaction of hydroxyl-containing acrylic ester and aliphatic polyisocyanate such as HDI trimer, has a paint film with excellent hardness and flexibility, and good chemical resistance. Its outstanding weather resistance, high gloss, good drying properties, and fast surface drying without dust adhesion make it the preferred topcoat in heavy-duty anti-corrosion coating systems. Due to its high hardness and excellent surface gloss, it is also used as polyurethane enamel and acrylic polyurethane enamel.

Durability:

Acrylic polyurethane topcoats have very good durability, especially in terms0 of yellowing resistance. In a dry environment, they can withstand temperatures up to 120°C, but some aging and yellowing may occur. If long-term color retention is required, the maximum operating temperature for equipment and pipelines is recommended not to exceed 80°C. Applying too thick a coat can lead to blistering or poor film formation, affecting its performance.

Chemical Resistance:

Acrylic polyurethane topcoats have good resistance to chemicals, crude oil, gasoline, and general solvents, but their chemical resistance is not as good as polyester polyurethane topcoats.

Paint Film Hardness:

The hardness of acrylic polyurethane topcoats is not as good as epoxy topcoats, so epoxy topcoats can be used in areas such as ship decks or walkways. In the early stages of curing, acrylic topcoats are quite flexible and thermoplastic. Therefore, adhesion testing on newly applied topcoats may show relatively poor results. Adhesion will improve over the following weeks. This is mainly due to the product being applied at low temperatures or applied too thickly, or it could also be due to the primer being applied too thickly, allowing solvents to remain and react with isocyanates, such as certain epoxy primers containing butanol solvents

Temperature resistance:

Acrylic polyurethane paint loses its gloss quickly in high humidity and high-temperature environments. Low temperature and high humidity environments, as well as condensation or rainwater on the surface immediately after application, can lead to discoloration, loss of gloss, and blistering of the paint film.