Styrotek produces expandable polystyrene produce containers. The Company was established in 1973 by local growers to develop a produce container which would protect, prolong storage time, and enhance the appearance of their fruit both in domestic and international markets. The majority of the containers are used for the packing of fresh market table grapes in the Coachella and San Joaquin Valleys. EXPANDABLE POLYSTYRENE GENERAL The material Styrotek uses to make its boxes is called expandable polystyrene (EPS). This material is a rigid cellular plastic, derived from petroleum products. We use it in our boxes for several reasons. The following paragraphs will detail those reasons along with giving you some of the other properties of EPS. STRENGTH When Styrotek receives its raw material, it is small beads weighing about 40 lbs per cubic foot. Styrotek expands these beads to a minimum of 2.5 lbs per cubic foot and then molds them into boxes. The strength of EPS is very dependent on the density to which the beads are expanded. The lower the density the less the strength. Styrotek uses 2.5 lb/ft3 material for stacking two pallets high as per our stacking instructions contained within this booklet. Styrotek also makes a high-density box, which is made from a minimum of 3 lb/ft3 for stacking three pallets high as per our stacking instructions contained within this booklet. Styrotek also continually tests random samples from the production on a test press in the laboratory. BOX WEIGHT Because of the strength properties of EPS, we are able to make a box that weighs approximately one pound, capable of being stacked in your cold storage. This is an advantage to you in several ways. The first advantage is in loading empties on the truck and unloading in the field. The boxes are so light that two men on a bob tail can load and unload a 1,000 boxes on a truck and be on their way in a very short time. Also, because the foam boxes have no slivers, nails or sharp edges, injuries to your employees are rare. THERMAL CONDUCTIVITY Expandable polystyrene is a good insulating material. Our box has ventilation holes to allow you to cool the grapes inside; but once the grapes are cold, the foam tends to insulate the grapes from the higher temperatures. The grapes stay cold longer. MOISTURE ABSORPTION EPS has excellent resistance to moisture absorption. Because of this property, the moisture in the grape stems and berries stays in the stems and berries. The box does not absorb moisture. This allows the fruit to be held in cold storage longer and still maintain quality. FLAMMABILITY Expanded polystyrene products are combustible and should not be exposed to open flame or other sources of ignition. When EPS is burned, the products of combustion are: Carbon monoxide Carbon dioxide Water Soot (carbon) The only potentially toxic products of combustion are carbon monoxide and carbon dioxide; but the amounts given off are far less than those given off by equal volumes of wood. Because of the black soot produced when EPS is burned, the air pollution board does not allow burning of broken foam boxes in the field. Broken boxes can be disked into the soil for soil amendment, taken to the dump, or returned to Styrotek, Inc. to be recycled. Styrotek will supply you with plastic bags that you can use to hold your broken boxes. As you accumulate a few bags have your bobtail bring them back to our yard when picking up additional boxes. If you have your boxes delivered to your field we can also arrange to pick up the bags of broken boxes. Styrotek will recycle these boxes that you bring back. OTHER PROPERTIES (1) EPS IS INERT. (2) Regular grades of EPS are safe for food contact. (3) EPS does not support bacterial growth. We hope this answers your questions about EPS. If you have other questions, please feel free to call the plant. Also, if you are interested in the manufacturing process, plant tours can be arranged on request.