Materials
No cans currently in wide use are composed primarily or wholly of tin; that term rather reflects the nearly exclusive use in cans, until the second half of the 20th century, of tinplate steel, which combined the physical strength and relatively low price of steel with the corrosion resistance of tin.
Use of aluminium in cans began in 1957. Aluminium is less costly than tin-plated steel but offers the same resistance to corrosion in addition to greater malleability, resulting in ease of manufacture; this gave rise to the two-piece can, where all but the top of the can is simply stamped out of a single piece of aluminium, rather than laboriously constructed from two pieces of steel. Often the top is tin-plated steel and the rest of the can aluminium.
A can usually has a printed paper or plastic label glued to the outside of the curved surface, indicating its contents. Some labels contain additional information, such as recipes, on the reverse side. A label can also be printed directly onto the metal.
In modern times, the majority of food cans in the UK have been lined with a plastic coating containing bisphenol A (BPA). The leaching of BPA into the can's contents is currently (as of early 2010) being investigated as a potential health hazard.
Read more about this topic: Tin Can
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