Modified polymer coatings are used when enhanced durability is needed. They offer abrasion and chemical resistance but also have an additional benefit. Most are less sensitive to colder environments. Once they are activated they will cure even in cold temperatures. Sometimes the time to dry is extended but they will cure out.
An extended dry time can pose a problem when there is the risk of someone coming into contact with the painted surface like what we just had painting doors and frames and some structural steel at a transit station for the City of Omaha. The areas were enclosed to protect the painted surfaces from blowing debris and so we could pump some heat into those areas.
The coating we used was difficult to work with. It was a two component modified polymer urethane. High performance coatings like this are often two component. The tinted base is mixed with an activator. You can also add some solvent to try to extend the dry time and make it easier to work with.
This urethane did not brush well. Between the cold temperatures and a difficult product to work with, this was not a fun job to do. We managed to prep the frames, doors and structural steel and get the first coat applied one day and return two days later for the second coat. The dry time was extended because of the cold.
The end result was good. The finish is very durable and will look great for years to come.