1.Essential difference
Physical foaming is to use physical principles for foaming, such as dissolving gas or liquid in plastic, and then making it expand or vaporize. Chemical foaming is a method to make the plastic melt full of bubbles by using the specially added chemical foaming agent to decompose by heat or chemical reaction between raw materials.
2.Different requirements for foaming agent
The requirements for physical foaming agent are non-toxic, odorless, non corrosive, non combustion, good thermal stability, no chemical reaction in the gas state, and the diffusion speed in the plastic melt in the gas state is lower than that in the air.
The requirement for the chemical foaming agent is that the stability is not required to be good, the gas released by its decomposition shall be non-toxic, non corrosive, non combustible, and have no impact on the molding, physical and chemical properties of the product, the speed of gas release shall be controllable, and the foaming agent shall have good dispersion in the plastic.
3.Different processes
In the technological process, the order of physical foaming is different from that of chemical foaming. The physical foaming process is first made of foam and then mixed, and chemical foaming is first mixed and then made into foam.
