Barrier Technology

  • PUBLISHED
Barrier Technology

Plastics are popular packaging materials because of their low cost, low density and the ease with which they can be processed into a large range of different products. Plastics suffer from some disadvantages compared to glass and metal. One major disadvantage of plastics is poor gas barrier properties. This is especially true of PP and the PE's. Of all the commodity plastics, PET has the best gas barrier properties, as can be seen in the following table:

Oxygen permeability of some commodity plastics
103.em3.Jlm.m-2.day.J.atm-1
LOPE 579
HOPE 93
pp 134
PET 4

For this very reason PET is used in applications like soft drink bottles to prevent the loss of carbonation. However, not even PET has sufficient barrier properties for many oxygen sensitive food and beverage applications. That is the reason why many fruit juices and beer are not currently packaged in plastics such as PET, but in glass, cans or cardboard/foil laminates. Many high barrier applications require multilayered packaging where PET is combined with high barrier plastics like ethylene vinyl­ alcohol, Nylon 6 or Nylon MXD6. However, often the capital equipment required for multilayers are expensive and recycling is a major obstacle. Also, the gas barrier properties are generally still not sufficient for demanding applications such as beer.


CCC ENVIROCLEAR BARRIER TECHNOLOGY SUMMARY


Container Corporation of Canada and its partners have developed and patented a novel barrier technology (hereafter referred to as the 'Technology') that yields excellent results wi th barrier properties 45 times better than PET when applied to PET and 25 times better than PET when applied to polypropylene.


The technology is based on a two layer outside coating using conventional spray-coating (or dip-coating) and drying equipment after surface activation. The inner coating is water-soluble and also the barrier, with the outer coating the protective coating. The coating enhances the physical appearance of the container by adding a gloss to the surface and can be applied to different thermoplastics such as PET and PP. The barrier bottles meet all the technical requirements for beverage packaging, including adhesion testing, scuffing, oxygen permeability and expansion testing.


COMPETITION

TECHNOLOGY DESCRIPTION APPLICATION COMMENTS
Amcor/Bairocade (developed by PPG) 2 material epoxy-amine thermoset (one coat) Solvent based spray applied system (outside) Containers packaging (Aust.) to supply 400ml monolayer bottles to Carlton & United Brewery (Carlton Cold and Foster's light)
Tetrapak Plasma coated extremely flexible SiOx coating (inside) Can be applied to applications beyond beer market Busy with initial equipment design and production
Sidel 's Actis I 000 angstrom thick yellow- brown amorphous carbon coating (i nside): microwave energy (acetylene gas) Sold between 20 - 30 Actis systems worldwide Need FDA approval (inside coating) Recycling issues Brown coating (cosmetic) Contin uous process?
Kirin's diamond like coating (DLC). Commercialize technology with Mitsubishi Plastic and Nissei ASB Plasma coating (i nside) Process and apparatus (si ngle cavity) difficult to expand to commercial scope. Potential patent conflict with Side!
SiOx Plasma Coating by Eastman and AirCo with a JV called Eastapak. SiOx coating (outside) Better coating than amorphous carbon but stiffer Batch-to-batch inconsistency Economics not acceptable
BESTPET from Coca- Cola. Krones and Leybolds Continuous SiOx coating systems (outside) Containers can be moved in and out of vacuum line while maintaining vacuum. Barrier only 2 - 3 t imes more barrier than PET ( not sufficient for beer)
Edge Technol ogies (DuPont) Two coat system Barrier coat is water releasable 30 times gas barrier of PET
ANC (Ameri can National Can), CPT (Continental PET Technologies), S-L (Schmalbach- Lubeca) and Kortec Co-injection multilayer (3 material. 5 layer) PET based bottles Recycling an issue