Aluminium Foil: Characteristics and Properties

Thinner films using less material are always being developed, addressing the strong demands for sustainable production – particularly in the packaging arena. Life Cycle Assessments (LCAs) indicate that alufoil packaging and household foil contribute less than 10% of the environmental impact in a product‘s lifecycle.

Alufoil’s total barrier to light, gases and moisture is the principal reason for its use in flexible laminates for food, drink and technical applications. Even when very thin, it provides perfect protection and preservation of aroma and product characteristics. It can help to extend the viable life of sensitive products for many months, even years, fully retaining valuable aromas. By enabling products to be preserved for long periods without the need for refrigeration, alufoil packaging helps to prevent spoilage and can provide large energy savings.

Even thin foil gauges can have excellent tensile strength making them easy to work with and robust material for many different environments. Shape, thickness, alloy and temper can be selected to create the exact performance characteristics required.

Because of its dead-fold properties alufoil can be used to wrap all kinds of intricate shapes and almost any size of product or component or be applied to complex constructions such as ducts or pipes. When pressed into a particular shape the aluminium foil memorises this, particularly where folds and rims occur.

Because it is so light the material is easy to transport in bulk and can be stored on large reels or even as preformed flat packs. Containers made from more rigid thicker foils can be ‘nested’ – so one inside the other - which not only saves space, but is ideal for the magazines of automated fill and seal machines. All along the supply chain this enables significant energy savings in a number of areas – helping to reduce the Carbon Footprint.

Particularly in the construction, automotive and aeronautics sectors using alufoil in honeycomb structures endows rigidity and strength whilst offering great weight savings. For rigid trays used in packaging designers are producing formats which offer easier handling in hazardous environments such as the oven, while better strength over larger surfaces for buffet service or other catering applications.

Aluminium s completely recyclable, potentially from whatever format it is made. Only the means of collection prevent some alufoil being recycled. All around the globe better recycling habits and systems mean every year, more and more of the material is recovered for re-use. The good news is that recycling aluminium uses only a fraction (5%) of the energy used in primary production – with correspondingly huge environmental impact savings. As better separation techniques become more widespread, more and more household waste finds itself in the recycling stream. For any foil which ends up uncollected this can be incinerated – which releases energy for re-use. Even the aluminium, which is not oxidised by incineration, can be collected from the bottom ash and recycled.

If aluminium foil is not collected for recycling but processed in incinerators the thin, laminated foil material is oxidised and releases energy, which can be recovered. In addition, the remaining non-oxidised aluminium can be extracted from the bottom ashes of the incinerator and subsequently used for recycling purposes.

As well as being a great insulator against cold it is an excellent conductor of heat and power when required. So it can enhance cooking performance or dissipate unwanted heat quickly – whichever is required. This heat dissipation can also help to reduce or minimise sealing times, which can save energy and reduce the chances of ‘hotspots’, which could damage the product. It can also stand up very well to extremes of heat and cold without any loss of performance – no distorting, melting, or splintering.

There are many examples of alufoil’s effectiveness as an insulator. Finned heat exchangers made with foil provide both cooling and heating in every modern vehicle.. Additionally it reflects up to 98% of light and infrared heat. The bright surface has low heat emissivity, helping to save energy. Another insulation role is fire protection -  ‘fire walls’ for vehicles and ships, fire-resistant doors and building panels, etc. Aluminium foil dissipates heat and stops access to the oxygen required to support flames.

Alufoil is completely sterile due to the high temperature annealing process. It is safe for use in contact with foodstuffs and it does not sustain or promote the growth of bacteria. Uncoated material will not react with the vast majority of foods.

Alufoil is safe for use in contact with foodstuffs. Uncoated aluminium foil will not react with the vast majority of foods. In many applications alufoil is not in contact with the product as it is used in association with other materials within a laminate. In addition it is an ideal protection against product tampering and can support anti-counterfeiting features.

Printing on foil can add lustre and quality to a package to enhance the product inside and even offer anti-counterfeiting or tamper evidence features such as holograms. Other decorative techniques such as embossing or etching are now becoming much more widely used.

Aluminium foil reflects up to 98% of light and infrared heat. The bright surface also has low heat emissivity. This helps to save energy in insulation. Its insulation role extends into fire protection. In ‘fire walls’ for vehicles and ships, for fire-resistant doors and building panels, aluminium foil dissipates heat and stops access to the oxygen required to support flames.

Aluminium foil is a totally effective buffer to magnetic and radio frequency emissions. In fibre-optic cables, alufoil acts as a ‘tracer’ to enable testing of the integrity of cable links. In cable wrap, electrical conductivity enables the integrity of the cable circuit to be verified.