| EPS foam starts at very small beads - similar to sand | | | | large feed screw in order to transport the already |
| in texture called polystyrene - the raw material is called | | | | expanded material to be steamed again. All pre- |
| Styrene. Styrene can be found nearly everywhere, in | | | | expanders have in common that the completely |
| your local food store and the local electronics stores. | | | | expanded beads trickle into a so- called fluid bed dryer |
| The plastic utensils are made of - Styrene, CD cases | | | | where they are dried and stabilized before they are |
| and cloth hangers - all made of Styrene.EPS which | | | | transported into the storage silos. |
| means Expanded Polystyrene, starts as the small | | | | The two most common blowing agents used are |
| beads. | | | | pentane and carbon dioxide - neither contains CFCs. |
| The next step in the process is to "blow" these small | | | | This process - polymerization - fills the polystyrene |
| beads into larger beads about 50 times its original size. | | | | with millions of air pockets, which helps it to expand |
| Depending on the density required, the beads are | | | | and also gives it a low thermal conductivity. |
| blown using steam in a machine called "expander" | | | | During expansion, the product can be molded into a |
| The expander can be a simple machine that a worker | | | | variety of shapes and sizes. The final product is 90% |
| places the raw material, and then turns on the steam, | | | | air, but amazingly, EPS can have a compressed |
| or an automatic machine where the material is | | | | strength up to 40 psi. |
| weighed automatically Steam, then is enables | | | | The last step in the process is the mold machine. Mold |
| (automatically) and then stopped.At this stage, the | | | | machine are divided into two main categories Block |
| beads are up to 50 times their original size. | | | | molds and shape mold machines. |
| Continuous pre- expanders are operated without | | | | Block mold machines create a block of foam - from 3' |
| pressure and are equipped with an open- top agitator | | | | x 2' x 8' up to 5' x 5' x 24'Block Mold can be done |
| tank in which raw material is continuously fed from the | | | | manually or automatically. If manually, once the molding |
| bottom by an adjustable screw conveyor.. Steam is | | | | process is done |
| "also fed continuously into the pre- expanding room | | | | The workers need to open the doors of the mold in |
| through openings that are positioned shortly above the | | | | order to remove the block from the mold. |
| tank bottom. An agitator and fixed breaker rods make | | | | On the machine above, this process is done manually. |
| it more difficult for bead clusters to develop; they keep | | | | Molding can also be done with an automatic EPS block |
| the beads in motion and make sure that al ready | | | | mold machine |
| pre-expanded beads of lower density move to the top | | | | Shape mold machines create different shapes - |
| of the bead bulk and fall into a shaft through a height- | | | | bicycle helmets, surfboards, RC planes, packing foam |
| adjustable discharge opening.Pre- expanders for the | | | | food packing and any shape imaginable that is not a |
| so- called "second pass expansion" of already | | | | block. |
| expanded materials are equipped with an especially | | | | |