Canadian Plastics

Film Enhancements Increase Stiffness

Although still in their infancy, Cargill Dow's NatureWorks polylactide (PLA) polymers are well suited to replace incumbent materials in some packaging applications. PLA is a new polymer derived from n...

September 1, 2000   Canadian Plastics



Although still in their infancy, Cargill Dow’s NatureWorks polylactide (PLA) polymers are well suited to replace incumbent materials in some packaging applications. PLA is a new polymer derived from natural plant sugars extracted from corn.

The resin is readily extruded, and gives enhanced properties when oriented. PLA films show good stiffness, twist retention and sealability.

A facility being built in Nebraska to manufacture the polymer should be on-line in 2002.

Another stiffness booster is Ticona’s Topas cyclic olefin copolymer (COC). When Topas is blended with linear low density polyethylene (LLDPE), a resulting 2-mil monolayer film has significantly greater stiffness than LLDPE alone. “The new blend runs like any LLDPE, but gives a more substantial-feeling film,” reports Mirek Planeta, owner of Macro Engineering & Technology Inc., which ran the blend on a blown film line during NPE. “The COC also improves film clarity and frictional properties like anti-block and slip, as well as sealing and moisture barrier.”

A technological development by Brampton Engineering Inc. has opened up the possibility of new high-barrier film structures. The ISO-therm SCD (streamlined coextrusion die) isolates the processing temperature of various layers in a multi-layer structure, permitting combinations such as nylon and PVDC. Brampton Engineering president Bill Wybenga says it is now “practical to use these materials in a coextrusion structure without the degradation seen in the past.”

The potential new film structures could be used for myriad applications, such as nylon/PVDC for processed meat packaging to PP/PVDC films for retort packaging, to polyolefin/PVDC for industrial packaging. As an alternative to foil-lined paper bags, thick barrier film will be able to run on form, fill and seal packaging machinery.


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