This type of adhesive includes thermoset epoxies, urethanes, and polyimides. This reaction causes polymers to cross-link into acrylics, urethanes, and epoxies - See thermosetting polymers. Thermosets are subdivided into several resin systems including epoxies, phenolics, polyurethanes, and polyimides. Epoxies and neoprene adhesives can be used for bonding ASA with woods and metals. These include epoxies, polyurethanes, and cyanoacrylates. Acrylated epoxies are useful as coatings on metallic substrates, and result in glossy hard coatings. They are stronger than polyesters and more resistant to impact than epoxies. Examples of thermosets include epoxies, silicone, vulcanized rubber, polyester, and polyurethane. Classic two-package epoxies or polyurethanes would fall into this category. Polyester epoxies are used as powder coatings for washers, driers and other "white goods". Polyester resin and epoxies are toxic and noxious. Some epoxies are cured by exposure to ultraviolet light. These are filled epoxies that have moderate, mixed viscosity and a long gel time. Epoxies are also used as a structural glue. Both water-borne and solvent-based epoxies are used.