Recent evolution of global tinplate and can lid technology

Zhang Wencan

1. Chrome-plated iron and laminating iron
Tin is the main strategic resource, but developed countries do not have this mineral. So after World War II, the Bethlehem Steel Plant in the United States, with the cooperation of Heintz, built the first chrome-plated iron in 1953 (abbreviated as TFS or ECCS). production line. After that, the US Steel Corporation, Yangston Steel Plant, etc. also quickly followed up. So the United States is still one of the two countries that produce the most chrome-plated iron (with 15 production lines) and the other is Japan.
Japan later in the United States, in 1961, the first chrome-plated iron production line was established by Toyo Steel Co., Ltd. The product was named Hi-Top and mass-produced, and the quality was very good. At that time Fuji (the later Nippon Steel) company. It was also built in 1962, and after that, the chrome-plated iron production line, soon, Toyo Steel Pipe NKK, Hachiman, and Kawasaki all worked hard. When the output was the highest, eight production lines were used throughout Japan. After 1998, the output of Japanese chrome-plated iron TFS has remained above 600,000 tons, more than 50% of his total use. Especially in recent years, on the one hand, the price of tin has increased by 60-70% (from 50,000 yuan to 80,000 yuan / ton), on the other hand, the manufacture of chrome-plated iron is simpler than tin plating because it No need to reflow, just plating in chromic acid solution. In general, the normal TFS product has a corrosion resistance comparable to that of a tinplate of 2.8/2.8 g/?, while the adhesion to the inner and outer prints is much better than that of the tinplate. So before the 1990s, it was widely used in the United States and Japan. This can be covered from the cans of the United States (such as tomato sauce, asparagus, sweet corn, etc.), most of which can be confirmed by chrome-plated iron.
However, TFS has a great disadvantage, that is, both sides must be coated with a protective coating film, and the printing process will cause serious benzene pollution to the environment and humans. And some of the inevitable trace residues of many paints have been considered harmful to human health in the past 10 years.
Therefore, from Japan in the late 1980s, the laminating iron was successfully produced. In 1991, the laminating iron in Europe was also put into production. The film covered (bonded) by the laminating iron is a multi-layer polyester composite film (thickness of about 20-25 microns), which blocks the penetration of corrosive media. , far superior to the printed film, and close to "complete repression." Therefore, it can directly cover the multi-layer polyester composite film on the steel substrate without the tinplate which protects the tin layer. This completely abolished the food science cans (especially in other tanks) for more than a hundred years. In theory, only a steel substrate can be used. However, in practice, chrome-plated iron TFS is still used as a substrate in various countries.

Production of iron and steel in Asia and Europe in early 2005
Production plant output (tons) Total production (tons)

Nippon Steel Nagoya 170,000

490,000

Fukuyama 120,000

Toyo cans Simomatsu 200,000

Korea

TCC Toyo 55,000

105,000

Donbu Dongbu 50,000

Colas Corus Group

British Trostre 30,000

135,000

Belgium Duffel 40,000

Germany Rasselstain 50,000

Lorraine Sollac, France 15,000

As shown in the table, since the laminating iron eliminates the high pollution problem of printing and printing, and Japan has a small number of people, it has forced it to become a big country for production and all laminating iron (the total domestic consumption is about 1.2 million tons). 40%).
The laminating iron of Japan's major groups is highly complex due to the use of high-temperature lamination and rapid recrystallization techniques, etc., so the composite fastness is extremely high (as is the case in Western European countries). China's laminating technology has already started, but because of the low-temperature bonding, the adhesion fastness is not as good as that of Japan, and improvement is still needed.
Second, the progress of DRD stamping tanks and secondary cold rolled sheets
The skyrocketing tin resources and harsh environmental requirements have forced the rapid development of laminar iron in recent years. Also, due to various lamellar irons (including laminated aluminum), laminating iron (coated aluminum) which is not suitable for leaving is mostly. As a result, a wide variety of stamping tank DRDs (and cupping DI) are becoming more popular. The three-piece cans have been gradually reduced in developed countries due to the complicated production, and instead, the stamping cans DRD and the cupping DI are used. Their largest applications are in the field of food cans and beverage cans.
I have pointed out many times that in the developed countries, most of the empty cans with a volume of less than 1000 ml have been used as secondary empty-rolled sheets with a thickness of 0.16 mm or less. Here, if a three-piece can empty can, the conventional secondary cold-rolled sheet is of course no problem and can be competent. However, if used for DRD stamping food cans, the mechanical properties of the secondary cold rolled sheet must also greatly improve its ductility.
From the quality of secondary cold-rolled laminar iron, Corus Group cooperated with Crown cans to study the doubling of the two-piece cans for food. The problem of adaptability between secondary cold rolled sheets and existing equipment. The concrete result is: with the French Lorraine sheet plant as the representative, it produces the secondary cold-rolled laminating iron with excellent elongation. It is most suitable for two-piece stamping cans and easy-opening caps (required when manufacturing easy-opening rivets) The elongation of the sheet is excellent). They named this material "Malai board." Its performance is as follows:
Ordinary tinplate

It can be seen from the table that the elongation of the mane plate is 10% at the hardness of DR-8, and that of the ordinary plate is 3%. According to reliable information, Japan also has products similar to the Manet board. The key to making such a thin and good stretchable sheet is vacuum smelting during steel making, which greatly reduces the non-metallic content of the steel, including carbon and certain metals. (To dozens of PPM levels), there is such performance.
Third, easy to tear cover
In the past two or three years, ESE has become more popular in China, with an annual output of about 2 billion. Of course, the quantity and quality must be further improved.
However, in foreign countries, in recent years, it has gradually become popular as an Easy Peeled End. The cover is actually a secondary cold-rolled aluminum sheet or a secondary cold-rolled steel sheet with a thickness of 70-130 μm (0.07-0.13 mm), which is cleverly sealed on an empty can by mechanical and heating techniques. Due to the tearing of the use, certain types of EPE can withstand high temperature sterilization. Now, in the global empty cans appraisal organized by the International Can Making Association in recent years, the awards related to EPE easy to tear cover are listed below: