Sponges are made of wood fibers or foamed plastic polymers. Sponge is a porous material with good water absorption, which can be widely used to make sofas, mattresses, boss chairs and sports equipment, such as sponge gymnastics mats, sponge fitness mats, sponge wrestling mats, sponge car cushions and other products. In addition to lignocellulosic fibers, there are three kinds of synthetic sponges made of other materials, namely low-density polyether, polyvinyl alcohol and polyester. Sponge is a kind of foamed polymer. Sponge has the characteristics of fine structure, smooth surface, soft and elastic feel, good cushioning, earthquake resistance, heat insulation, moisture resistance, chemical corrosion resistance, non-toxic, tasteless, water absorption, etc., which can effectively prevent products from being impacted during transportation, and does not contain polluting chemicals and denatured plastics.