Can be organic or inorganic substances, chemical or physical methods, to produce the foam (foamed plastic). A foaming agent, can reduce the amount of plastic needed to produce the component, so that the desired weight reduction, the cost will be reduced. Blowing agent may be in small quantities to improve the hardness, insulation, to prevent shrinkage and have the ability to produce the plastic thick walls. Amount of the blowing agent, will decide porous plastic (porosity); using a foaming agent products that can be imitated leather, vinyl floor mats, packaging materials, sponges, coffee mugs, and bedding. Blowing agents, chemical reaction can occur to form a gas, or may be physically expanded, to form a foam structure. Chemical blowing agent, will be at high temperatures, decomposition of gas, and then expand the plastic materials. Physical blowing agent, as the heat expansion, forming a porous structure forced.