Multi-wall Package

A method for the fabrication of a multi-wall package has been described (19). The package consists of biodegradable paper layers, and sheets of adherent films. The film sheet may consist of a corn derivative or PLA. Further, stripes are positioned in such a way that the package is more easily foldable in a lateral direction than in a longitudinal direction. 

The layers are fabricated by progressive and controlled extrusion of the adhesive via extruders which are laterally spaced apart. The sheet is travelling in longitudinal direction imder the extruders. Advantageous properties of the products include (19)  

The films have been further characterized as sufficiently leak proof to withstand, at least temporarily, any wetness associated with pet food (19). 

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The Chemistry of Bio-based Polymers 7.1.8 Multi-wall Package... 

D.F. Brulz, Multi-wall package, US Patent 8 387 797, assigned to Precision Color Graphics, Ltd. (Franklin, WI), March 5,2013. 

Class II (NFPA 231/231C)—Class II commodity is defined as Class I products in slatted wooden crates, solid wooden boxes, multi-wall corrugated cartons, or equivalent combustible packaging material on wood pallets. 

Other hot melts are based on low molecular weight polyethylene, combined with tackifying agents. These tend to be lower in cost and performance than the EVA-based hot melts, and they are used primarily with paper packaging, such as cartons and multi-wall bags. Atactic PP can also be used as the base for hot melt adhesives. Pressure-sensitive hot melt adhesives for tapes and labels often employ thermoplastic elastomers, consisting of block copolymers of styrene and butadiene or isoprene. 

Applications General purpose flexible packaging and laminating Sugar pouches, industrial and multi-wall bags... 

The standard package was a heat sealed, aluminum foil lined, multi-wall paper container holding 30 lbs. of product. The moisture proof container was used to reduce the effect of moisture pickup on melt flow. This made it easier to mold parts to the desired tight dimensional tolerances. 

The main fluids of interest with plastics are oxygen and water vapour (for packaging applications) and CO2 (for carbonated drinks applications). Fig. 1.13 and Fig. 1.14 illustrate the type of behaviour exhibited by a range of plastics. In some cases it is necessary to use multiple layers of plastics because no single plastic offers the combination of price, permeation resistance, printability, etc. required for the application. When multi-layers are used, an overall permeation constant for the composite wall may be obtained from... 

Demertzis P G, Johansson F, Lievens C and Franz R, 1997, Studies on the development of a quick inertness test procedure for multi-use PET containers - sorption behaviour of bottle wall strips. Packaging Technology and Science 10,45-58. 

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