Resource Efficient Innovations Database (REID)

Active microlayer technique extends the barrier properties of food packaging

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Active microlayer technique extends the barrier properties of food packaging
A new technique combines the concepts of active packaging and microlayer extrusion to deliver significantly longer shelf-life
In Development – EDI plans to produce samples for tests at its Technology Center and then have the results confirmed by an outside laboratory.

Benefits
Packaging Reduction, Product Waste Reduction, Shelf life extension

Product Categories
Drinks, Food

Relevant Materials
Plastic – Flexible, Plastic – rigid, Plastics - Other / mixed

Relevant Packaging Formats
Bottles and jars, Flexible & Films

Supply Chain Phase
Production

Details

An innovative technique adds a new dimension of oxygen and moisture control to food packaging, possibly extending barrier properties beyond the limits of standard test procedures.
Called "active microlayer" technology, the new technique combines the concepts of active packaging and microlayer extrusion, yielding film and sheet in which layer multiplication is applied not only to the barrier polymer but also to active components, such as oxygen absorbers or desiccants.

Previous research has demonstrated that by dividing and recombining the barrier layer to create many micro-barrier layers it is possible to increase significantly the shelf life of retort and hot-fill containers, stand-up pouches and vacuum skin packaging. Further work incorporated active components in layers outside the barrier core and then subjected those components to layer multiplication as well.

The layer multiplication technology (LMT) yields film or sheet that is no thicker and contains no more polymer than a conventional coextrusion yet can have dozens of, or even a hundred or more, microlayers instead of the usual 3 to 11 layers of standard thickness. In conventional coextrusion, a feedblock combines different polymers from two or more extruders into a multilayer sandwich. In LMT, a special tool takes the sandwich from a feedblock and divides and recombines the layers, creating multiples of the original multilayer structure.
The combined protection of food contents by multiple-even dozens-of barrier and active layers appears to be greater than standard tests for oxygen and moisture ingress are designed to measure, according to EDI, the company which is developing the technique. EDI plans to produce samples for a new battery of tests at its Technology Center and then have the results confirmed by an outside laboratory.
Here is an example of how a typical active microlayer structure could be produced in the form of polypropylene (PP) sheet of 1.25-mm thickness:
● Four extruders produce melt streams of, respectively, 1) the PP outer material or skin; 2) the same PP skin material, but incorporating an active component such as an oxygen scavenger; 3) an adhesive or "tie" layer material; and 4) a barrier polymer such as EVOH.
● Feedblock No. 1 receives the "active component containing" skin material, along with the tie and barrier materials, and forms a five-layer sandwich: active-component/tie/barrier/tie/active component. This sandwich will evolve into the inner core of the finished sheet.
● Layer multiplier, a special tool built by EDI, receives the five-layer sandwich from Feedblock No. 1 and divides and recombines it to form multiple repetitions of the structure-for example, four repetitions, resulting in a 20-layer structure consisting of micro-layers.
● Feedblock No. 2 receives the 20-microlayer structure and the melt stream of PP outer material, diverting the PP into two skin layers over the microlayer core.
● Extrusion die: In the manifold of the die, the sandwich from Feedblock No. 2 is transformed into sheet of target width.

The content in this entry has been obtained from publicly available information sources only (e.g. press releases, website and trade press articles) and is subject to completion of a validation process with the technology supplier.

Potential Benefits

The high barrier performance indicated by the trial work to date suggests this technology has the potential to deliver significantly extended shelf-life for food products (and therefore product waste reduction) whilst using less packaging material.

Intellectual Property

EDI has a patent pending on this technology.

Consultant View

The results communicated to date suggest that this technology has considerable promise in terms of improved shelf-life extension. However, there are also other technologies which can provide improved product shelf-life. Readers interested in finding other solutions should try searching the REID database using combinations of filters and search terms such as “Food”, “barriers”, and “active packaging”.

Contacts and Further Information

Extrusion Dies Industries, LLC
911 Kurth Road
Chippewa Falls, WI 54729
715-726-1201 fax: 715-726-2205
Email: sales@extrusiondies.com

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