Application of metal tin in food packaging
March 07, 2022
Tin is a kind of silvery white and soft metal. It is similar to lead and zinc, but it looks brighter. Its hardness is relatively low, and it can be cut with a knife. It has good ductility, especially when the temperature is 100°C, it can develop extremely thin tin foil, and its thickness can be as thin as 0.04 mm.
Tin is also a low-melting metal. Its melting point is only 232°C. Therefore, a candle flame can be used to melt it into a mercury-like liquid with good fluidity.
Pure tin has a peculiar property: when the tin rod and the tin plate are bent, it will give off a special kind of crackling sound that seems to be crying. This sound is caused by the friction between the crystals. When the crystal is deformed, such friction occurs. The strange thing is that if the tin alloy is changed, it will not make such cries when it is deformed. Therefore, it is often based on this characteristic of tin to identify whether a piece of metal is tin.
One of the main uses of tin metal is to make tinplate. Tinplate is often referred to as "tinplate", which is a tin plated tin. Do not look at the thin tin layer above, but it is a very useful "coat." The iron coat put on this coat is not only beautiful, but also obtains many excellent properties.
Then, what are the fine qualities of the “clothes” of tin? To put it simply, it is: It can resist both corrosion and poison.
Why tinplate has such a good quality? This is inseparable from the nature of Tin. It turned out that the chemical properties of tin are very stable. It does not react chemically with water. Even if it is exposed to humid air for a long time, it will only gradually form a dense oxide film on its surface. This layer of film can prevent the continued oxidation of tin. Tin coating resists corrosion.
In addition, the role of tin and inorganic acids is very slow, with little effect of organic acids, and tin salts are generally non-toxic, so tin plated tin is often used as food packaging materials, such as food cans , biscuit boxes and so on.
