Blowing agent is defined as the polymer-based or decomposition due to heat generated gases, thereby resulting polymer foam material of a class of auxiliary holes.
 

    Classification of blowing agents: physical blowing agents and foaming agent can be divided into two major categories of chemical blowing agent. Chemical foaming agents are divided into inorganic and organic foam blowing agents. Hence the name. Physical blowing agent is mainly chlorinated hydrocarbons, or chlorofluorocarbons on behalf of the hydrocarbons, such as the three chlorofluorocarbons methane, trichloro-trifluoro ethane and so on. Mainly used to produce polyurethane foam. The main varieties of chemical blowing agent is Azodicarbonamide (blowing agent AC) and N, N'-2-nitroso-5-methylene tetramine (blowing agent H), the former used for plastics, the latter commonly on the rubber.