Definition - What does Polyurethane Coating mean?
A polyurethane coating is a layer of polyurethane (a type of polymer) that is applied to a material's surface in order to protect it. A polyurethane coating can protect the base material from corrosion, weathering, abrasion and other processes that would degrade the material over time. A polyurethane coating can be glossy or muted, and can be opaque or transparent.
Corrosionpedia explains Polyurethane Coating
Polyurethane coatings are considered polymers. They can be very hard and strong, providing exceptional wear resistance. They can also be more soft and ductile, so that the base material is allowed to stretch without destroying the coating. Polyurethane coatings are not flammable, so they can be used for some situations where combustion is occurring in the same environment. Care must be taken to limit the exposure of a polyurethane coating to ultraviolet light because it can cause the coating to degrade.
Polyurethane coatings are notable for their ability to adhere very well to a wide variety of base materials. Many polyurethane coatings require no additional processing to cure. They are simply applied and cure upon exposure to moisture in the air. Some polyurethane coatings also have very fast setting times, and can be applied and set in a broad range of temperatures. They can be sprayed or rolled onto a base material.
Polyurethane coatings are used for many different applications. Wood floors are often coated with polyurethane. Since polyurethane coatings can be waterproof and have high abrasion resistance, they are an excellent choice for this application. Polyurethane coatings are also used on metals and on top of other coatings.