Polyurethane is substantially made of two raw materials — isocyanate and polyol, which are derived from crude oil. After mixing those two process-ready liquid components of the system and various auxiliary materials, such as catalysts, foaming agents, and stabilizers, a chemical reaction starts. Polyurethane foam is the result of a chemical reaction when its two components are mixed. The basics of the reaction are the expansion and gel phase. During the initial reaction phase, a small amount of CO₂ gas is released and trapped in the liquid mixture. This creates small bubbles. As these bubbles multiply and expand, the mixture also expands or rises. The more the liquid foams in this initial reaction phase, the less dense the material. The resin then cures and hardens around the bubbles, creating a uniform matrix of cells. This cellular structure is strong. When the cells remain closed, the structure is watertight and airtight. They provide perfect adhesion to both vertical and horizontal surfaces, and it has porous structure. Porous materials have hollow cavities inside. Porosity is a property that tells us about the volume and quantity of pores with certain diameter. Polyurethane foam is also characterized by a short treatment time and, after curing, it retains its chemical neutrality. Polyurethanes demonstrates good thermal parameters — it is resistant to a wide range of temperatures (from –200°C to +135°C). Average thermal conductivity coefficient of polyurethane foam is 0.026 W/m2 The components of the polyurethane foam must be well mixed to initiate the reaction. This can be done mechanically with a mixer.