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Aluminium foil: its strength is its lightness
This year aluminium foil is celebrating its 100th anniversary. During its history it has driven forward technological developments, set trends and clad innumerable chocolate Father Christmases and Easter bunnies. And these are just a few examples from the long success story of this unique packing material.
The demand for aluminium is rising from year to year. Many applications and developments require a light yet stable material and both these requirements are met by aluminium. It is enormously versatile and is found in all sectors of the economy, from building materials and the transport industry through to mechanical engineering and plant construction up to packaging. Aluminium’s really big strength is its lightness - coupled with high stability, good thermal and electrical conductivity, particularly high corrosion resistance and outstanding recyclability. On top of this, aluminium comes with no health hazards or risks and is a naturally occurring resource found with various other elements. Traces of aluminium are also present in baking powder, processed cheese slices or toothpaste. As a result, it would be impossible to imagine the packaging industry without the material: it protects foodstuffs and chemical preparations against quality-degrading influences and enables space-saving transport. Be it an Easter bunny, yoghurt, ready meal, medication or canned drink: aluminium is a flexible, multi-functional and light packing material, which can also meet the highest product design standards and requirements.
Thinner than a human hair
Aluminium’s diversity of application areas and advantages are matched by its variety of processing possibilities. Stretch-forming process or drawn products, mould casting or innovative alloys – practically everything is possible. In cold and hot foil rolling mills the aluminium ingots are also rolled into plates, sheets, strips and foils, which in some cases are only 6/1,000 (6 microns) millimetres thick and thus much thinner than a human hair.
Aluminium foil is used to describe products, which are less than 0.2 millimetres thick. Today they are mostly cold-rolled from pure aluminium in several rolling cycles and thus classified as semi-finished products. The starting material is pre-rolling strips, 0.6 to 1.5 millimetres thick. In the manufacture of thinner foil of up to four thousandths of a millimetre two webs are placed on top of each other and simultaneously rolled. The exteriors are given a smooth, shiny surface by the work rollers, while the interiors rub together producing a rough, matt surface. After the marked deformation the aluminium stabilizes and strengthens, while the foils are hard and brittle. It is not until the subsequent soft annealing process is applied that they become soft and flexible - and thus an outstanding packaging material for foodstuffs and medication packaging, which is also gas tight and light proof. Depending on the application, hard or soft foils are required. 54 square metres of aluminium foil with a thickness of seven thousandths weigh just one kilogram. This lightness is its really big strength.
100 years of aluminium foil production
This year aluminium foil is celebrating its 100th anniversary. On 15th April 1905 the Swiss entrepreneur Heinrich Alfred Gautschi was granted the patent on the manufacture of aluminium foil according to the “pack-rolling or multi-sheet/paper-rolling process”. However, he did not see its main use as packaging, and only relatively small foils were produced. In cooperation with Erwin Lauber and Albert Gmür, Robert Victor Neher, also from Switzerland, developed a process for rolling out endless strips, which was patented on 27th October 1910, but was also still initially intended for other applications. In the same year "Dr. Lauber, Neher & Cie." was founded in Emmishofen, Switzerland.
In 1913 the first trials began aimed at manually finishing foil sheets in aluminium. They were used for example in the mechanical packaging of chocolate, boxed cheeses and cigarettes. They were quickly followed by other applications such as chocolate or stock cube wrapping. Also founded in 1910, the Aluminium GmbH in Teningen, and in 1912 a subsidiary of the Emmishofen company in Singen, Germany. In 1920 aluminium foil conquered the milk industry and increasingly displaced tin foil. From 1930 aluminium household foil was produced in Europe as a small package in roll format, as a tear-off block or loose sheets in cardboard pockets. In the USA aluminium foil was produced for the market from 1913 onwards, in around 1920 the first boxes lined with aluminium foil were used. The 50s and 60s saw a spectacular growth phase for the packaging material. In the companies at Singen and Teningen aluminium foil is produced and finished to this day. Up to 2010 both companies were part of the Canadian aluminium manufacturer Rio Tinto Alcan and in the meantime have been taken over by the Australian company Amcor Flexibles.
Responsibility for the future
Today aluminium foil is used in practically all market segments. The packaging applications extend to aseptic fluid cartons, the most diverse pouch forms, lids, wrappers, blister and strip packs, foil containers etc. With the new millennium the manufacturers are also faced with new challenges: sustainability is the major theme. Aluminium foil also fulfils the best prerequisites. The success in "Downgauging" aluminium foil has led to material savings of over 30 percent. On top of this aluminium is an almost endlessly recyclable material: according to Yale University, USA, approximately 75 percent of aluminium ever produced has been in the metal material cycle since 1888 and is constantly being reprocessed and recycled.
