Lightweight and sturdy europallets with EPS, HIPS and SBC-Polymer

imageHirsch (Glanegg, Austria) launched a new europallet made of EPS (core) and HIPS (surface film), modified with Styroflex® 2G66, a highly elastic styrene butadiene copolymer from BASF. The new pallet weights much less than wood europallets and it is also easy to clean (washable) and resistant enough for the common logistic use. The lightest model weights 5 kg and can handle 1 ton!

In order to minimize the weight of their new plastic pallet, engineers at Hirsch have developed a rigid and strong core made of expanded polystyrene (EPS) for this standard transport structure. To withstand damage during the rough-and-tumble daily routine of logistical operations this structure has to be protected by a very robust skin. This is why the developers turned to a two-layer film made of BASF’s impact-resistant polystyrene (HIPS) whose layers have Styroflex added to them. The one to two millimetres thick film wraps the pallet tightly.

While the special styrene butadiene copolymer serves in other applications in the form of films, in this case it is used as a toughness modifier for impact resistant polystyrene. Even in small amounts, it can considerably boost the basic toughness of HIPS, cost-effectively turning it into a material that can withstand severe mechanical stress. The Charpy notched impact strength of the basic polymer and the energy needed to puncture the product are markedly increased. As a result, the new pallets can withstand all of the jolts, impacts and shear loads normally encountered in routine logistics operations without suffering any appreciable damage.

According to BASF experience, Styroflex 2G66 also makes the material less prone to stress cracking as characterized by the so-called environmental stress cracking resistance, abbreviated ESCR. Furthermore, the addition of Styroflex 2G66 also enhances the compatibility among the materials and creates a non-slip surface. Packaged goods are much less prone to slipping on the HIPS-Styroflex film than on smooth polyethylene.

The pallets do not absorb water. This is not only advantageous for the transportation of frozen products, where absorbed moisture unnecessarily consumes cooling capacity, but it also means that the plastic pallets do not have to be extensively treated against mold and rot. The modified HIPS surface can be easily cleaned with regular power washers, which makes it the ideal transportation material for food products. Together with the requisite food contact approvals, the new pallets are also suited for the safe transportation of food. Since all of the materials involved come from the polystyrene family, it is, moreover, much easier to recycle the pallets once they have finally reached the end of their useful life.

Last but not least, from a designer’s standpoint, the plastic version is much more flexible with regard to design parameters than the obdurate wooden variants. For instance, pallets sporting the colours of the customers, and even with moulded indentations or printed with company logos, are all conceivable. RFID tags can easily be inserted under the protective film, so that the route travelled by pallets identified in this manner can be continuously tracked all over the world.

BASF’s styrene butadiene copolymer has already proven itself in other respects of product logistics: In multilayered shrink-wrap or stretch hood films the material helps to effectively secure goods during loading and unloading as well as during handling at the warehouse. For this application films made from pure Styroflex are combined with polyethylene in multiple layers. Here, the product can come up with additional particular properties. Due to its remarkable recovery capacity – even after being stretched by 220 percent – the film once again clings tightly to the items. Pure polyethylene films for industrial use can only be stretched between 20 and 50 percent without loosing their stabilizing function. In the case of stretch hood films made of Styroflex the high puncture resistance together with the high crack resistance of the elastic polymer represents an additional advantage, especially when packaging sharp items.