Protection and Finish
Acrylic urethane cracks more easily than polyurethane. Acrylic urethane also offers a much lower degree of protection from ultraviolet rays than polyurethane.
For this reason, polyurethane often is added to acrylic urethane. The combination creates a shinier finish.
The solvents contained in certain polyurethane compounds also help protect finishes from ultraviolet light radiation. This property makes polyurethane paints ideal to use in house painting.
Acrylic urethane is easier to spray, wet sand and buff than polyurethane. Acrylic urethane is commonly used for car paint restorations.
Polyurethanes, comprised of multiple urethane into compounds called polymers, are harder and more rigid than urethanes. They bond well with metals and plastics.
High concentrations of polyurethanes are mixed into paints to make finishes scratch and chip resistant. Polyurethanes also can be used in high- or low-heat applications.
Durability and Toxicity
Acrylic urethane does not provide as much protection from the elements as polyurethane. Polyurethane paints also offer a higher degree of chip and scratch resistance than acrylic urethane.
Urethane is toxic to small animals and pets. Polyurethanes, because of their compounds, pose a lower risk.