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W&H pushes polyolefin film extrusion to the limit with new die technology

A new die design tailored specifically for polyolefins is allowing Windmöller & Hölscher (W&H) to churn out tissue film at an output of more than 1000 kg/hr from its stand in Hall 17 Stand A59. The 5-layer 400-mm Maxicone P die is being fed from a Varex blown-film extrusion system at the base of a more than 15m-high tower.

October 27, 2010

3 Min Read
W&H pushes polyolefin film extrusion to the limit with new die technology

A new die design tailored specifically for polyolefins is allowing Windmöller & Hölscher (W&H) to churn out tissue film at an output of more than 1000 kg/hr from its stand in Hall 17 Stand A59. The 5-layer 400-mm Maxicone P die is being fed from a Varex blown-film extrusion system at the base of a more than 15m-high tower. At the top of the system, the bubble is split into two 47-inch roles, with no edge trim, thanks to better control of the internal bubble.

The “P” stands for polyolefins and W&H worked with ExxonMobil Chemical, a supplier of Exceed and Enable metallocene polyethylene (mPE), to create a new generation of 5-layer films using a polyolefin base. The tissue film would normally run with a 3-layer design, but the new 5-layer setup sandwiches a blend of high-density and low-density PE between layers of Enable mPE, with the two outer layers constructed from Exceed mPE blended with HDPE. The final structure improves the film’s properties while allowing the entire system to be downgauged. At K, the final film is 40-µm thick.

The typical design of polyolefin films inverts the structure seen in barrier systems, which W&H services with its Maxicone C system, by having the inner layer as the thickest. In a barrier film, inner layers are downgauged to minimize the use of expensive barrier resins like EVOH and nylon. A W&H representative told the KSD that in many 3-layer systems, processors want specific properties on the outer layer, optimizing films for printing or lamination, for instance. For this system, a different screw is utilized in the extruder, with W&H specifying one for high output of polyolefins at lower temperatures. Those lower temperatures help stabilize the bubble. Following the K, the line will go to Danafilms Inc. (Franklin, KY), where it will be outfitted to run as a 7-layer line, making it that company’s second W&H 7-layer system.

In addition to tissue overwrap, the new die can be used in a number of polyolefin-film based applications, including collation shrink films, tissue overwrap, laminations, and industrial bag applications.

The line also features W&H’s Opticool single air-ring, with one air ring increasing output over two-ring systems by 20% through a proprietary air-distribution design that avoids pressure drops. In addition to lowering costs, the single air-ring setup also makes for easier line startup, when processors must pull a bubble.

Also at its stand, the company is displaying a 52-inch Miraflex AM 8-color printer, with color-matching capabilities. Following the K, Bema Polytech (Elmhurst, IL) will take delivery of the printer.

Business wise, the North American unit of the German company is enjoying a record year, according to the W&H representative. Including global sales, the company says it has returned to levels last seen in 2008 and is “very optimistic for the future.” In a release, W&H published approximate sales at e500 million, across all its groups.

In addition to its stand at the show, W&H is running a concurrent open house at its headquarters in Lengerich, with four blown-film systems, including its new Aquarex water-quenching line, as well as a cast-film line, machine-direction orientation (MDO) system, and a Polyrex shopping bag machine. At this point, more than 700 people have signed up. Registration for the event, which takes place, which takes place on Thursday and Friday of this week and Monday and Tuesday of next, is available at W&H’s stand with complimentary shuttle service available. —Tony Deligio

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