Thermoplastic and Thermoset Foams

The foam industry can be divided into two major segments: thermoplastic foams and thermoset foams. Thermoplastic foams include polystyrene, polyethylene, and polypropylene. Polystyrene foams are commonly used in food service and food packaging as well as extruded insulation board. Polyethylene and polypropylene foams are used as pipe insulation and in many packaging applications.

Thermoset foams include polyurethane, polyisocyanurate, and phenolic. Typical applications for polyurethanes are appliance insulation, integral skin foams such as shoe soles, and insulated metal panels and doors. Polyisocyanurate and phenolic foams are used in applications where building codes require less combustible materials such as roofing insulation and exterior wall sheathing.

Blowing agent properties differ among the various foam applications. Blowing agents used to produce appliances and construction board are selected because they contribute to the insulation value (low vapor thermal conductivity) of the foam. Insulation value is not as important in packaging foams; blowing agent selection for these foams is based upon economics, safety, and environmental needs.