Tin, ferroalloy and tinplate are iron sheets with a layer of tin on the surface, which are not easy to rust. They are also called tinned iron. It is made by soaking iron sheet in molten liquid tin. Tin is a metal less active than iron. It is neither oxidized by air nor reacts with water, so it has quite strong corrosion resistance. A thin layer of tin plating on the iron sheet can play a good protective role. However, once the coating is destroyed and electrochemical corrosion occurs, because iron is more active than tin, iron will be oxidized and lost as the negative electrode of primary battery. The existence of tin will accelerate the corrosion rate of iron, so tinplate is different from white iron, and iron can only be protected if the coating is intact. Where Sn is the coating, also known as tinned iron.
(Pay attention to the distinction between white iron, zinc and iron, in which zinc is the coating, which is the common name of galvanized iron).
Tinplate is a common name of tinned steel plate, abbreviated as SPTE, which refers to cold-rolled low-carbon steel plate or steel strip with commercial pure tin on both sides. Tin mainly plays an anti-corrosion and anti-rust role. It combines the strength and formability of steel with the corrosion resistance, weldability and aesthetics of tin, and has the characteristics of corrosion resistance, non-toxicity, high strength and good ductility.
The origin of tinplate
Tinplate originated in Bohemia (now Czechoslovakia). This place has been rich in advanced metal technology since ancient times and knows how to use water power to make machines. Tinplate production began in14th century. For a long time, it has been the main producing area of tinplate in the world. At that time, tinplate was mainly used to make tableware and drinking utensils.
Development of tinplate industry
/kloc-in the 0/7th century, Britain, France and Sweden all wanted to establish their own tinplate industry, but they needed a lot of money. So it has never been developed. Until 18 1 1 year, Brian? Jintang and John? After Hall founded tinplate canned food, tinplate manufacturing industry developed on a large scale. Today, the world produces about 250,000 tons of tin every year, of which more than one third is used to make tinplates, and most of them are used in canned food industry.
A brief history of tinplate development
18 10: The world's first tinplate can was invented by the British and patented. At that time, a can-making expert could make 60 empty cans a day.
1900: invention of electric welding machine.
1847: American invented can-making machine to replace manual labor.
1965: the aluminum easy-to-open lid began to be used to make cans.
1973: iron easy-to-open lid was used to make cans.
1990: improve the canning process and produce more than 1 0,000 cans per minute.
The origin of tinplate name
Tinplate was called tinplate in the early days, and its official name should be tinned steel plate. Because the first batch of foreign iron in China was imported from Macau in the middle of Qing Dynasty, Macau was transliterated as "Ma Kou" at that time, so China people generally called it "Tinplate".
Characteristics and advantages of tinplate
1. opaque
Light can not only cause food deterioration, but also cause changes in protein and amino acids. However, after being exposed to light, vitamin C is more likely to interact with other food ingredients, causing a lot of losses. According to research and analysis, the loss of vitamin C in transparent glass bottled milk is 14 times higher than that in dark bottled milk. Light will also cause oxidation smell in milk, and the loss of nutritional value due to the cracking of nuclides and methionine. Opaque tin cans make the preservation rate of vitamin C the highest.
2. Good sealing performance
The barrier of packaging containers to air and other volatile gases is very important for preserving nutrition and sensory quality. Comparing various fruit juice packaging containers, it is proved that the oxygen permeability of containers directly affects the browning of fruit juice and the preservation of vitamin C. Metal cans, glass bottles, laminated aluminum foils and cartons with low oxygen permeability can better preserve vitamin C, among which iron cans are the best.
3. Reduction of tin
Tin in the inner wall of tinplate will react with the residual oxygen in the container during filling, reducing the chance of oxidation of food components. The reduction of tin has a good preservation effect on the flavor and color of light-colored fruits and juices. Therefore, canned fruit juice packed in unpainted tin cans has better nutrition preservation, slight browning, better flavor quality acceptability and longer shelf life than canned fruit juice packed in other packaging materials.
4. Provide an effective source of iron
Tinplate canned food, except for a few light-colored fruit and juice cans, mostly uses empty cans painted inside to improve the corrosion resistance of containers; Due to the electrochemical action of metals, a small amount of iron will be dissolved from painted cans during storage, and it exists in sealed cans in the form of bivalent iron, which is easily absorbed by human body, and the content is about 1 ~ 10 ppm. As far as fruit and vegetable products are concerned, the iron content of raw materials is not much. Iron can products can provide 1.75mg of iron, which is about one tenth of the daily intake 18mg based on the iron content of each 350 ml beverage can. If canned fruit and vegetable juice drinks are rich in vitamin C, iron is more easily absorbed, so canned food and drinks are good sources of iron, which has far-reaching significance for providing nutrition for canned food.
Because of these characteristics, tinplate can provides a closed system, which is completely isolated from environmental factors except heat. Color-avoiding food will deteriorate due to light, oxygen and humidity, will not fade due to fragrance penetration, and will not change its taste due to environmental odor pollution. The storage stability of food is better than other packaging materials, with the highest preservation rate of vitamin C and the best preservation of nutrients.
The use of tinplate
Tinplate is widely used, from food and beverage packaging materials to oil drums, chemical tanks and other miscellaneous cans. The advantages and characteristics of tinplate provide good protection for the physical and chemical properties of the contents.
1. canned food
Tinplate can ensure food hygiene, minimize the possibility of corruption, effectively block health risks, and meet the needs of modern people in convenient and fast diet.
2. Beverage cans
Tinplate cans can be used to fill fruit juice, coffee, tea and sports drinks, as well as coke, soda and beer. However, the high processability of tinplate can makes the shape of tinplate can change greatly, no matter how tall, short, large, small, square and round, it can meet the diversified needs of beverage packaging and consumer preferences.
3. Grease tank
Light will trigger and accelerate the oxidation reaction of oil, reduce the nutritional value, and may also produce harmful substances, more seriously destroying oily vitamins, especially vitamin D and vitamin A.
However, the oxygen in the air will promote the oxidation of edible oil, reduce the biomass in protein and destroy vitamins. The opacity of tinplate and the isolation effect of sealed air are the best choice for packaging oily foods.
4. Chemical storage tanks
Tinplate is strong, protective, non-deformable, impact-resistant and fire-resistant, and it is the best packaging material for chemicals.
5. Spray and other cans
Tinplate cans that can withstand high temperature and high pressure are especially suitable for spray cans filled with high pressure. Biscuit barrels, pencil boxes and milk powder cans with varied shapes and exquisite printing are all tinplate products.
Tinplate packaging material meeting environmental protection requirements
Existing containers include tin cans, aluminum cans, paper and plastic containers. The recycling characteristics of these containers are different, but the recycling of tin cans is better than other packaging materials.
Based on the international environmental management standard ISO- 14000, tinplate cans with the characteristics of low pollution, recycling and resource saving will have a broader development space in the future packaging and use;
1. Low pollution:
Tinplate, the main raw material of tin cans, is actually harmless to the environment and can be naturally decomposed. Because tin cans exist in the environment and can be naturally oxidized back to the original iron oxide state and return to nature, the stacking of scrap iron cans can be time-distorted and will not cause environmental pollution. At the same time, it is not necessary to cut down trees to make tin cans, so as not to destroy the ecological balance.
2. Recyclable:
The tin can itself has a characteristic that other packaging materials do not have-it can be adsorbed by magnets, so that the tin can can be separated from the garbage by magnetic force with a magnetic separator, and the effect of recycling 80% of the tin cans in the garbage can be easily achieved by using this characteristic. The invention of the environmental protection cover not only makes the use of tin cans safer and healthier, but also effectively reduces the amount of garbage, which has direct and obvious benefits for recycling operations.
3. Provincial resources:
In the aspect of removing other pollution residues from tin cans, chopper equipment has been developed, which can effectively remove more than 98% pollutants and provide scrap iron with good quality. In addition, the United States also pointed out that the existence of aluminum easy-to-open cover is beneficial to scrap iron recovery, because it can reduce the amount of molten iron used in steelmaking and reduce the overall cost of steel manufacturing. In addition, in terms of energy saving, the report pointed out that compared with iron ore production, using tinplate scrap to produce steel can save about 230m3 of natural gas per ton, so the tin can recycling process can reduce the impact on the global environment and energy, which is in line with the future product trend.
There are many companies that produce tinplate in China.
For example:
Zhongshan Zhongyue tinplate industry co., ltd
Jinzhou Hualong tinplate products co., ltd, etc. ...