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When you get your aluminium foil bags or rolls and you are told that your purchase will protect the contents of your package from the potentially destructive action of moisture, oxygen, vapours and odours, you will be happy and consider that it has been a job well done. You will be correct. The foil, or to be more precise, a thin layer of aluminium foil inside a plastic sandwich, will allow less than 0.03 grams of moisture per m2 to pass across it in 24 hrs. Of course, this protection can be extended considerably by adding desiccant (silica gel, activated clays, etc).

HOWEVER, what if you do not want moisture, gas, etc. getting to your product at all – even at very low levels?
Well, this is possible.

The rate of moisture transmission across thin layers of aluminium foil is governed by the number of small pin holes which will allow transmission of minute levels of moisture, etc. This number is controlled by the technological know-how involving the manufacture / rolling of thin metallic layers.
Thin foil, 7 microns (0.007 mm) contains many very small holes but it is relatively inexpensive and has good barrier properties. Thicker foils, upwards of 25 microns (0.025 mm), get around this problem. Granted, the foil is a little more expensive but it has the ultimate of barrier properties.
At this thickness, no gases, no vapours, no odours, are allowed through it.
It does not have any holes at all.

If this thought is appealing, phone Protective Packaging on 0161 976 2006.

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