Polyol is a macro molecules of poly hydric alcohols with molecular weights ranging from 200 – 20000 with functionalities ranging between 2 and 8. The polyol when reacted with isocyanate, which contains a NCO functional group, reacts with the OH functionality of the polyol in the presence of suitable catalysts to form urethane/urea linkages. The catalysts accelerate the reaction to the required level. The blowing agents blows the cells increasing its volumes to form the light weight polyurethane foam. The surfactants promote and stabilizes the polyurethane cells and helps to retain the shape into which it has been blown to. Blowing agents are produced in situ as well as externally added into the reaction mixture. Non-foaming applications normally do not contain blowing agents.