The processing methods can be divided into mode method and extrusion method according to different foaming methods. This uniform closed cavity structure makes EPS have the characteristics of small water absorption, good heat preservation, light weight and high mechanical strength.

Expanded foam (EPS) is a kind of light polymer. It uses polystyrene resin to add foaming agent, and at the same time, it is heated to soften to produce gas, forming a rigid closed cell structure of foam plastic.