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Developments in multilayer films
A high-octane session of development on multilayer films was moderated by Jayesh Rambhia, president, The All India Plastic Manufacturers’ Association. This session discussed developments in extrusion technology and production of high barrier films.

Raymond van Hoorn, technical sales manager - extrusion, Windmöller & Hölscher, Germany, explained important high barrier film applications in India, which can be classified as oil films, milk films, and tube laminate film. He highlighted the features of Varex blown film lines. Hoorn said, “Cost savings can be achieved by reduction in edge-trimming using Varex lines.” Later he presented some of the products from Windmöller & Hölscher such as Procontrol TS; purge assist module; and easy change module.

Kurt Freye, director, Sales Worldwide, Reifenhauser Kiefel, Extrusion GmbH, Germany, said, “The growth in polyethylene demand in Indian subcontinent is about 9% as compared to 5% worldwide in 2012.” Freye highlighted Reifenhauser Kiefel’s Evolution blown film lines: Dual lip; ECP (heavy-duty shipping sacks); Evolution Ultra Cool and related products such as extruders, die-heads, cooling systems, take-off systems, winders etc.

The third presentation of the session was delivered by Carl Johnson, president, Gloucester Engineering USA (GEC) that discussed the roll conformity issues in high barrier film extrusion. Johnson said, “Many times poor film quality or roll geometry is blamed on the winder or the collapsing process. Many of these issues are caused further upstream all the way back to the quality of the extruder melt temperature.” The melt temperature variation primarily leads to excessive variation in film thickness causing variable mechanical properties, additive performance, and web tension during printing and lamination.

After discussing the effects and causes of melt temperature variation, Johnson displayed GEC’s solution, light-grooved feed (LGF) Technology, to add value to the extrusion process. He said, “Efficient polymer feeding in combination with efficient heating can result in lower energy cost. This can be achieved with LGF.”

Explaining Modified Atmospheric Packaging (MAP) and Equilibrium MAP, Frank Bernotat, sales and project management head in plastic, Hosokawa Alpine, discussed the extrusion line requirements; standard five- and seven-layer barrier films; and the advantage of nine-layer films. Bernotat said, “The step from seven-to-nine layer leads to an increased complexity, however on the other side this leads to a higher flexibility in layer design and increased economic efficiency.”

Mike Horsfield, vice president-business development, Brampton Engineering delivered the final presentation of the session titled, "comparison of water-quenched versus air-cooled blown film in high barrier applications". The barrier properties of air-cooled blown barrier film are lower as a result of lower crystallinity as compared to water quenched blown barrier film and thus film clarity is superior.

Describing the process of water quenched blown film, Horsfield said, “A downward extruded bubble is blown up to its desired diameter, rapidly cooled upon contact with the chilled water in the water ring. The extremely rapid heat removal minimises the time the melt spends in the crystal-growth temperature range, producing a film of unique properties. The bubble is subsequently collapsed, randomized with an oscillating haul-off, drawn by a secondary nip, and wound into rolls.”

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Consumer packaged goods – industry overview and developments in materials