What is polyurethane foam?
Polyurethane foam spray or spray is the most common type of foam insulation, manufactured in the United States by the US Army for use in aircraft, and used as a foam insulator in the early 1990s. One application of polyurethane foam is the insulation of objects. These chemicals are made up of two main ingredients: polyol and isocyanate, both of which have a liquid nature. After mixing, the two materials react with each other, expanding into foam and solidifying for a while. This rapid drying will produce a relatively permanent insulation that will neither crack nor deform. If the foam extends beyond the desired area, the extra foam can be cut to the desired size.

Benefits of polyurethane foam
The advantages of polyurethane foam include:

Low thermal conductivity lower than all other conventional insulation materials
light weight
High strength
Great ability to accept formulation changes to meet applicable expectations
Strong adhesion to many materials
Low vapor permeability
High thermal resistance