SBC-based films adopted for stretch hoods

BASF (Ludwigshafen, Germany) says its Styroflex 2G66 styrene-butadiene copolymer (SBC) is going into serial production of films for stretch hoods.

BASF says companieslike Bischof + Klein (B+K) and PCI Augsburg have opted for Styroflex on the basis of its high stretchability and recovery capacity, which allow it to secure a wide array of palletized loads.

Compared to the polyethylene (PE)-based films it’s working to enhance, Styroflex-derived systems have shown in tests that film containing Styroflex wraps tightly around a load and holds it securely on a pallet, even after being stretched by as much as 220%. Ulrich Drögsler, head of sales at industrial packaging firm B+K, which is using Styroflex to produce the stretch hood films in its SmartFlex SE series, said that films made of pure PE can only be stretched between 20-50% in industrial uses without its recovery capabilities being adversely impacted.

In addition, BASF says Styroflex film’s high puncture resistance allows it to be thinner than pure PE films, which can range from 80- to 120-µm thick. The company says the greater stretchability and reduced thickness of the new product lower the film weight per pallet, and the overall improved pallet stability cuts insurance and logistics costs. BASF adds that Styroflex, even as an SBS, can be processed as a regular low-density polyethylene (LDPE) would be.

In terms of the layer structure, a Styroflex-based stretch-hood film is normally constructed in 1/3/1 ratio, so that a 100-µm stretch-hood film would have layer distribution of 20 µm/60 µm/20 µm. BASF says the two outer layers can basically be the same as standard stretch-hood recipes, and by varying the Styroflex layer thickness and the composition of the outer layer, a custom film can be designed. In addition, no tie layers are needed in combination with mLLDPE (metalocene linear low-density PE), which is normally used in outer layers.

In terms of pricing, BASF told MPW that Styroflex is priced at a premium compared to currently used TPO, but adds processors should compare the price per hood. Depending on the stretch-up ratio, film thickness, and exact recipe, an individual evaluation has to be made. BASF also believes Styroflex exhibits less pricing volatility than olefins.

PCI Augsburg (Augsburg, Germany), a manufacturer of building chemicals and BASF subsidiary, is using the film to pack items with sharp edges, including tile adhesives in buckets and footfall-insulation panels.

Even if a pallet is tilted by up to 35%, Styroflex’s inherent tear resistance and recovery capacity allow the film to continue to stabilize the load.

B+K is currently developing a UV-resistant SmartFlex SE film based Styroflex, to create a film that’s suitable for outdoor applications like roof tiles, garden furniture, and chemical products. The film is already undergoing testing and is expected to be commercially available in mid 2009. —[email protected]