PS processing conditions

Generic Class

PS (Polystyrene)

Typical Applications

Packaging, housewares (tableware, trays, etc.), electrical (transparent housings, light diffusers, insulating film)

Injection Molding Processing Conditions


Not usually required unless stored improperly. If drying is needed, the recommended conditions are 2-3 hours at 80 C (176 F). 

Melt Temperature 

180 - 280 C (356 - 536 F); upper limit is 250 C for flame retardant grades (19 - 158 F)

Mold Temperature

Suggested: 20 - 70 C (68 - 158 F) 

Material Injection Pressure

20 - 60 MPa 

Injection Speed

Fast speeds are recommended 

Runners and Gates

All types of conventional gates may be used.

Chemical and Physical Properties

General-purpose PS is produced by the polymerization of styrene. Most commercial grades are clear, amorphous polymers. PS offers excellent dimensional and thermal stability, optical clarity, and very little tendency to absorb moisture. It has good dielectric properties. It is resistant to water and dilute inorganic acids, but is attacked by strong oxidizing acids such as concentrated sulfuric acid, and is swollen by some organic solvents.

Processing shrinkage is typically between 0.4 - 0.7%.