Foaming plastic products are a kind of polymer materials with plenty of gas micropores filled in solid plastics. They have performances of light weight, heat, sound and corrosion resistance and shock absorption, etc.
Compared with non-foaming plastic products, foaming plastics have advantages of low density, light weight and high strength. They also have performances of shock absorption, sound resistance, low heat conductivity and excellent performances of electric insulation, corrosion and mucedine resistance. Soft foaming plastics have excellent flexibility.
Classification of Foaming Plastics
Foaming plastics can be divided into 3 main types as per their hardness: rigid foaming plastics, semi-rigid foaming plastics and soft foaming plastics. The elasticity modulus of soft foaming plastics should be less than 70MPa under 23 oC and relative humidity of 50%.
Foaming plastics can be classified into 3 main types as per their density: low foaming plastics, medium foaming plastics and high foaming plastics.
Whatever foaming method is used for foaming products making, the final result is to get foaming plastics. The general foaming process is turning plastic raw materials into liquid or melt form and then filling in gas into plastic raw materials. The gas will make micropore ( bubble) inside the material and then these bubbles shall be fixed after they increase to some certain size. Otherwise, there will be no foaming plastic products.
There are three general ways to mix gas into polymer materials: mechanical method, physical method and chemical method.