How Expanded Polystyrene is Made.
What is Expanded Polystyrene (EPS)?
Expanded Polystyrene (EPS) is a synthetic closed celled hydrocarbon polymer foam composed of carbon, hydrogen, and oxygen. There are no chlorofluorocarbons (CFCs) or blowing agents used during manufacturing. The product is lightweight with over 98% of it’s volume being composed of air. The most recognized expanded polystyrene brand name is Styrofoam™, however, most expanded polystyrene products are produced by local independent manufacturers such as Great White Foam.
How Expanded Polystyrene (EPS) is Made
Step 1 : Raw Bead
Great White Foam receives raw bead from our quality suppliers. The raw bead is quality control checked and the grade and batch numbers are record for traceability.
Step 2: Expanded Bead
The raw bead is fed into the pre-expander where raw bead is scaled to confirm the accuracy. Upon confirmation the raw bed proceeds into the expander. The expander circulates the bead as steam is injected causing the bead to increase in size by 9.5-40 times depending on grade. The expander scales three samples of 1 cubic ft of expanded bead which verifies that process was completed to specifications.
Step 3 : Expanded Bead Storage
The expanded bead is carried into hoppers where it can off-gas the remaining pentane. The process takes 1-3 days depending on the grade.
Step 4: Billet Moulding
Expanded bead is fed from the hoppers to the billet mold where it is compressed and injected with steam to fuse into oversized 3’ x 4’ by 14’, 16’, 17’, or 18’ long blocks.
Step 5 : Curing
Billets are stored in a curing room to allow water within the EPS to evaporate. The process of proper curing will ensure the dimensional stability of the billet.
Step 6: Finished Product
The cured billets are cut to manageable 7’, 8’, 9’, or 10’ long block lengths. EPS Molders then cuts products into sheets or produces custom shapes on our CNC.