Blowing in the wind

That, says Andrew Wheeler, VP at blown-film extruder manufacturer Windmöller & Hölscher, is what would happen if someone were to separate the 1-µm layer of ethylene vinyl alcohol (EVOH) out of the nine-layer, 94.5-inch- (2400-mm) wide barrier film being extruded on this Varex blown-film line. The EVOH layer is so thin it would simply float away.Barrier films must do what the name implies?guarantee a barrier?so processors often must run the (generally costly) barrier material’s layer thicker than they would like to ensure proper performance. To prove this is unnecessary on its equipment, W&H extruded the nine-layer, 30-µm- thick barrier film for eight-hour stretches on all three days of its recent open house in Lengerich, Germany. The Varex unit was fitted with a 20-inch (500-mm) Maxicone die and extruded 1468 lb/hr (665 kg/hr). “sWhen your barrier material costs are over $3/lb, the ability to cut the amount required by 50% or more [down from 2 or 3 µm] results in huge savings,”s noted Wheeler. The EVOH layer that provides the barrier in this film was sandwiched between two 1.5-µm-thick nylon layers, followed by two layers of adhesive, two mLLDPE layers, one EVA layer, and a layer of LDPE. Windmöller & Hölscher KG, Lengerich, Germany; +49-5481-14-0; www.wuh-lengerich.de