The two main materials which are used for a spray foam are the polyol resin and the isocyanate. These two reacts when mixed together and will enlarge 30 to 60 times the volume of its liquid when being sprayed. One advantage of its expansion is that it is useful for packing a certain material and forms its shape, thus, producing a thermal insulation of high value. So this means that the higher the value of product, the more potent its insulation properties.