Expanded Polystyrene foam is manufactured from the by-products, or left overs, from the oil refining process. FPM is a “Block Molder” of EPS which means we mold EPS into large blocks 36” x 48” x 120” in size. These blocks are then cut into smaller usable sizes that vary with the application. The description below explains how manufactures the EPS foam pieces and sheets you are familiar.
Buys raw material in the form of resin or beads of styrene. Each bead has a microscopic dot of Pentane formed into its center. This material is furnished in air tight bags. These bags keep the beads “fresh” by assuring that the Pentane within each bead can not escape into the atmosphere and render the material.
These beads of Styrene are about the size of a grain of salt and have a similar consistency. It is crucial that the beads are stored in a tightly controlled environment where the amount of Pentane within their plastic shell remains consistent. Each step of EPS production requires strict adherence very tightly controlled quality standards.
These beads of resin are loaded into a machine called a “pre-expander”. It does exactly what the name implies. Steam is injected into the beads at 212 degrees F. The heat accomplishes two things. The wall of each bead is softened and becomes flexible and the increased temperature also causes the Pentane to expand within the softened beads. The beads puff up like popcorn to 30 times their original size.
The next step is the molding process. It is at this point that the individual expanded beads are molded into a single, homogeneous block. This is the most crucial stage in the production process and it is essential that very strict quality control standards are adhered.