Barrier Properties
Aluminium foil’s total barrier to light, atmosphere and liquids is the principle reason for its use in caps, capsules and lids.
Decorative Potential and Printability
Aluminium foil can be printed by most modern printing techniques and its bright or matt surface which can easily be embossed, provides designers with enormous scope to create image enhancing packs with special impact.
Dead Fold and Mechanical Properties
Aluminium foil is strong and can be laminated easily with other materials to give it additional properties. In coated or laminated form, it can be shaped to the provide protection and decoration as capsules for wine, champagne and other bottled drinks. When ‘unsupported’ by other materials it can be folded to follow the contours of complex bottle necks.
Hygiene and Product Security
Aluminium foil does not harbour or promote the growth of bacteria, is sterile following the thermal treatment during its production process. It is also an ideal protection against product tampering – whether as an extended bottle neck foil or as a secure closure diaphragm.
Sustainability
The high performance barrier of aluminium foil helps to save other materials, and cuts logistical costs. A high level of materials recovery can be achieved and, where separation is not possible the energy stored in thin foils can be utilised thermally.
Applications
Bottle Neck and Capsule Foils
Aluminium foil capsules or bottle neck labels add visual quality to any type of bottle. They are a valuable part of the product’s personality and a guarantee of authenticity. Imagine Champagne and traditional bottled beers without them!
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Figure 1. Aluminium foil bottle necks.
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But the foil is not just there for decoration. It also ensures security, provides tamper evidence in the case of ‘over the crown’ foil, and engenders consumer confidence in the quality of the contents. Aluminium foil’s physical properties of ‘deadfold’ and malleability enable it to cope with the contours of bottles and closures in an easy-to-apply and brand building way. Opening a twist-off cap or crown closure is easily done without disturbing the appearance of the neck foil thanks to tear off perforation. The art and technology of bottle neck foils is moving ahead continually, resulting in material savings whilst retaining elegant appearance and high product security. Champagne capsules are generally made from thicker gauge aluminium foil which is sometimes coated or laminated with a plastic layer. Aluminium foil has been adopted as the natural successor to lead as the material for spin-on capsules for wine bottles. Neck foils are frequently embossed which, apart from giving a distinctive appearance, also makes the labels easy to handle. Recent developments have also enabled smooth labels to be used. Labels with partial embossing adding an element of design appeal and individuality are a further option.
Hygiene Ensured for Drinks Cans
Printed and embossed aluminium foil diaphragms are now also being used as over-the-tab covers on beverage cans. Not only does this protect the top of the can from dirt, it allows the use of the can top area for further brand identity and provides a medium for special promotions and competitions without any change to the can body design. Both sides of the foil may be printed, so enabling ‘lucky can’ promotions or token collections. The ‘stackability’ of the can is not affected, temperature is no problem whether high or low, there is full tamper evidence because the foil cannot be removed and replaced without deformation, and the recyclability of aluminium capping material creates no separation problems when collected with the aluminium cans.
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Figure 2. Aluminium foil covers for beverage cans.
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Heat Sealed Closures
Although glass bottles for products such as milk have given way to plastic ones, more secure closures have had to be developed. Hence the aluminium foil membrane – peelable but secure. Although commonly used for dairy products heat sealed lids are also used on portion-sized drinks packs such as still water and juices in airline catering. These often involve aluminium foil coated with a variety of plastics and lacquers in order to achieve secure seals compatible with the wide variety of plastic containers – PS, PP, PE, PVC and PET.
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Figure 3. Heat seal aluminium foil closures for beverage packaging.
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Foil Labels
When it comes to creating a pack that reflects the luxury and quality of its contents aluminium foil labels can bring effects that really enable brands to create a distinctive identity with maximum shelf impact. Aluminium foil’s naturally decorative surface can often be enhanced by high quality printing, embossing or even using the ‘matte’ side of the foil to achieve an antique metal effect. As aluminium foil is compatible with a wide choice of printing and finishing processes – offset litho, gravure and flexo printing, punching, die cut shapes, laminating, lacquering, hot, cold and water-based adhesives and embossing – an aluminium foil laminated label offers an enormous range of options to designers.
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Figure 4. Aluminium foil labelling on beverage packaging.
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