tin can
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A tin can (also: can for short ) is a generic term for beverage cans and food cans . Both are thin-walled storage containers made of metal, sometimes combined with other materials. Tin cans are characterized by tightness, light protection, low mass, often stackability, as well as a certain stability and resistance to impact and corrosion.
Tin cans are typically cylindrical or prismatic in shape and made from 2 to 4 sheet metal parts. The bottom and shell can consist of 1 or 2 parts, as can the top surface.
Tin cans can be hermetically sealed, i.e. gas-tight, or just dust-tight. Only one cover lid can be opened by hand. To open hermetically sealed tin cans, extra cutting or levering tools or a tear-open device are required on the can.
Tin cans with round, pressed-in lids or with screw lids and gaskets can again be closed fairly hermetically. For cylindrical cans, extra elastic plastic lids are offered for a certain reclosing.
Tin cans are typically manufactured industrially. Tin cans are widely used for liquid, pourable or semi-solid foods, as well as paints and varnishes, solvents and oils.
Aerosol cans and metal containers with a tear-off foil attached can also be viewed as tin cans. If the volume of a sheet metal container exceeds a limit of 10–50 liters, it is referred to as a sheet metal barrel.
description
Until the introduction of plastic packaging, sheet metal in many forms was one of the basic packaging materials alongside glass , paper and cardboard until 1950. These include B. cans for paints, varnishes, solvents and especially toxins. Aluminum is often used as a material here.
Food cans are predominantly made of either aluminum or tinplate . On the purpose of a distinction between beverage cans and food cans , which were soldered before, but today at the ends of the can barrel with flange are sealed. The cans are glued or welded to the side . The grooves (also called beads ) rolled into the can jacket serve to stiffen the can body.
Tear-open boxes are provided with a half-stamped circular groove in the top surface and a finger ring. This ring is lever-like pulled away from the can lid, so that the shorter side of the lever as a load arm the can lid in an as predetermined breaking point depresses designed rolled-circular groove in the direction of the can bottom, and released from the can body. By pulling it up further, the lid can be removed from the can with relatively little effort.
In the GDR , the term “ can ” was also used for a tin can filled and sealed with food .
history
The tin canning process was supposedly invented by Frenchman Philippe de Girard and the idea was passed on to British trader Peter Durand , who was used to patent Girard's idea in 1810. A year ago before the French inventor Nicholas Appert , the canning concept was based on experimental conservation work in glass containers. Durand did not operate canned food, but in 1812 he sold his patent to two Englishmen, Bryan Donkin and John Hall, who refined the process and product and set up the world's first commercial canning factory on Southwark Park Road in London . Around 1813 they produced their first canned food for the Royal Navy . By 1820, tin canisters or cans were used for gunpowder, seeds, and turpentine .
Earlier tin cans were sealed with a tin- lead alloy by soldering , which could lead to lead poisoning . Unfortunately, on Sir John Franklin's Arctic expedition in 1845 , the crew suffered severe lead poisoning, believed to have been caused by canned food. Recent research suggests that the lead poisoning was more likely caused by the aqueduct system on the two ships.
In 1901 the American Can Company was founded in the United States , which at the time manufactured 90% of American tin cans.
materials
No cans in use today are made primarily or entirely of tin ; Rather, this term reflects the almost exclusive use of tinplate steel, which combined the physical strength and relatively low price of steel with the corrosion resistance of tin, in cans, which was used until the second half of the 20th century. Depending on the contents and the coatings available, some canned goods still use untinned steel.
In some local dialects, any metal, even aluminum , can be referred to as a “tin can”. The use of aluminum in cans began in 1957. Aluminum is cheaper than tinned steel, but in addition to being more malleable, it also offers the same corrosion resistance, which makes it easy to manufacture; This led to the two-part box, in which the casing and base are stamped and deep-drawn from a single piece of aluminum sheet.
A can traditionally has a printed paper or plastic label to identify and depict the contents. Often there is the shape of a band running between the folds around the can jacket, which is only glued to and together on one edge strip. Banderoles can therefore be easily torn off with the fingernail for the purpose of more precise waste separation, they even have a loosely protruding tear-off edge, they can easily be torn off starting there to remove any information on the back of the label, for example. B. to expose a prescription. More recently, labels have been printed directly onto the metal before or after the sheet metal is formed into individual cans. Cans can be marked with embossed fonts and graphics in the course of production. Stamping, printing with inkjet and laser engraving are also processes for the closed can.
Today the majority of food cans in the UK have been lined with a plastic coating containing bisphenol A (BPA). The coating prevents acids and other substances from corroding the tin or aluminum of the can, but the leaching of BPA into the contents of the can is currently (as of 2013) investigated as a potential health hazard.
Web links
- Life cycle of a tin can, teaching aids from swisseduc.ch
- More detailed historical information on the tin can
Individual evidence
- ↑ Fritz Jörn, FAZ from March 1, 2014, history of the can opener, had tin
- ↑ Income and purchase, consumption and supply situation - GDR - Myth and Reality Konrad-Adenauer-Stiftung eV Accessed on August 27, 2019 .
- ↑ Tina Schwarz: Filinchen, Brause, Nudossi: You paid for that in the department store in GDR times. February 9, 2019, accessed on August 27, 2019 (German).
- ↑ Tom Geoghegan: The story of how the tin can nearly wasn't . In: BBC News . April 21, 2013 ( bbc.co.uk [accessed April 25, 2018]).
- ↑ OilCans.net - American Can Company. Retrieved April 28, 2018 .
- ↑ Hertzberg, Ruth; Vaughan, Beatrice .: Putting food by . 5th ed. Plume, London 2010, ISBN 978-1-101-53980-4 .
- ^ Petroleum Week . 1959 ( google.de [accessed April 28, 2018]).