Novel Cooling System, Energy Efficient Extruders for Blown Film

Hosokawa Alpine American is highlighting some of its latest advancements in blown film extrusion. These include what’s believed to be the first U.S. showcase of the VarDAR Upper Cooling Air Ring.

The VarDAR is a variable-diameter, dual-directional-flow air ring which is tower mounted, providing cooling above the frost line to permit processors with a shorter-than-desirable nip height to improve productivity. The VarDAR air ring  is typically mounted above the main calibration basket and the oscillating thickness gauge, if so equipped. It generates an even curtain of cooling air that flows both in a downward and upward direction onto the film surface. The VarDAR ring uses multiple curved “blades” that ensure an even curtain of air surrounds the bubble around its total circumference.

Adding additional cooling above the frost line reduces effects such as blocking, which occurs when the inside surface of the bubble sticks to itself at the nip during collapsing, making it nearly impossible to open. This system also reduces tackiness of the bubble’s outer surface when still hot. 

Alpine will also be featuring its well-established X-Die, which continues to evolve and provide what the company says is the ultimate performance in layer-to-layer control, thickness control, job changeover and fastest purging time, as well as new developments in controls automation and film orientation.

It will also be featuring its Select extruder line, which is said to be flexible enough to run LLDPE, mLLDPE, PCR (postcustomer recycle) and bioplastics. A new screw and barrel design is said to permit energy savings up to 30% along with significantly lower melt temperatures and much higher throughput. This, in turn, results in increased bubble stability at lower cooling requirements, Alpine says. The series is available with screw diameters from 50 to and 120 mm.