The first use of aluminium for packaging was for sealing on glass bottles, dating back as far as the early 1900s. This was a successful application, mainly because the closure could be securely fastened to the somewhat irregular glass threads. Aluminium foil was used in packaging shortly after it was first produced in 1913.
Chewing gum wrappers took advantage of many of the desirable properties of aluminium foil. Impact extruded collapsible aluminium tubes were introduced in the USA in 1921. In the late 1950s, there was a trend towards using aluminium for a variety of rigid containers. The manufacturing properties of aluminium allowed such containers to be produced by the impact, stretching and bonding as well as the spiral winding of foil laminates.
Aluminium for packaging is mainly in sheet or foil form. Commercially pure aluminium is mainly used, although non-heat-treatable alloys of the aluminium-magnesium and aluminium-manganese types are also used to achieve higher strength. With commercially pure aluminium and alloys, a wide range of mechanical properties can be obtained through varying degrees of work hardening.
Flexible packaging materials and laminates with aluminium foil
Rigid containers made from sheets, foil laminates or drawn heavy foil, or extruded from blocks
Bottles and wide-mouth caps made from sheet or aluminium foil
Collapsible tubes, made from poppers by impact extrusion
In the glossary of packaging terms, flexible packaging is defined as involving the use of flexible materials such as foil, films, paper, and sheet, to form the container. Aluminum foil has become firmly established as one of the major flexible packaging materials. About 85% of all aluminum foil produced is used in some form of packaging. The three major packaging applications are household foil, 35%; laminated foil, 30%; and formed containers, 28.5%.
Aluminum foil is a sheet less than 0.0060 in. (0.15 mm) thick. It can be rolled commercially as thin as about 0.00017 in. (0.005 mm). An important characteristic of aluminum foil is its high covering area per unit of weight.
Aluminum foil is outstanding in its low permeability to water vapour and gases. Extremely small pinholes are unavoidable in thickness less than 0.001 in. (0.025 mm). Foil is tasteless, odourless, non-toxic, and hygienic. A special advantage of annealed foil is that it is substantially sterile because of the temperature (over 340°C or 650°F) of annealing. Foil is greaseproof and nonabsorptive to liquids and hence is especially suited for packaging medicinal oils, ointments, grease-base cosmetics, and similar products. Foil remains dimensionally stable during exposure to oils and greases.
Foil is an effective barrier to light and is used extensively to package photographic materials and other light-sensitive products. Ultraviolet radiation accelerates the development of rancidity in certain foods; foil is a good barrier to this radiation, retarding loss in flavour and appearance, and inhibiting the development of rancidity and staleness.
Because it is an efficient reflector and low emitter of radiant heat, aluminum foil is employed for packaging where the thermal insulating properties imparted by these characteristics are advantageous. Despite these insulating effects, the good thermal conductivity makes it possible to chill or heat aluminum packages more rapidly than those with nonmetallic covering.
The above information is provided by the aluminium foil manufacturer.